The Welding Research Council, Inc.
EVALUATION OF MATERIAL STRENGTH DATA FOR
USE IN CONJUNCTION WITH API 530
January 2011
M. Prager1, D.A. Osage2
1
2
Materials Property Council, PO Box 1942, New York, NY 10156
The Equity Engineering Group, Inc., 20600 Chagrin Blvd., Shaker Heights, OH 44122
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
1
The Welding Research Council, Inc.
ISBN No. 1-58145-548-8
Library of Congress
Catalog Card Number: 85-647116
Copyright © 2011 by
Welding Research Council, Inc.
All Rights Reserved
Printed in U. S. A
2
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
FOREWORD
This WRC Bulletin entitled Evaluation of Material Strength Data for Use in Conjunction with API 530 is
one of a series of Welding Research Council (WRC) Bulletins intended to capture in detail the
technical information that supports important and widely used international codes and standards such
as those of ASME and API. WRC and its Materials Properties Council (MPC) and Pressure Vessel
Research Council (PVRC) have for over 50 years played instrumental roles in advancing the
technology needed to assure reliability and safety of pressure vessels and structures.
The data for this project were gathered and analyzed by MPC under API contract. It was logical that
MPC was selected for this study of properties applicable to high-temperature tubular materials
produced by modern steel making practices for petroleum refinery heaters designed to API 530. More
than 50 years ago Dr. George V. Smith acting under the auspices of MPC and its forerunner, the
ASTM-ASME Joint Committee on the Effects of Temperature on the Properties of Materials, collected
and evaluated much of the data that was used by API to support the design curves that would appear
in API 530. The Joint Committee and MPC later pioneered in development of statistically rigorous
computerized techniques for analyzing and extrapolating elevated time-dependent mechanical
property data. The methods developed were applied to optimize Larson-Miller Parameter (LMP)
stress-rupture constants for each material as desired by API for use in API 530. Optimization of the
LMP constant enhances the accuracy of property extrapolation for the purpose of life assessment as
well as design.
The polynomial expressions provided for the LMP parameters and all other mechanical properties in
this Bulletin are intended to support computerized design and life assessment activities. For further
details about tools for life assessment the reader is referred to API/ASME FFS-1. Detailed
presentations of solutions to the examples in this Bulletin facilitate implementation of the methods
used.
The assistance of Mary Buchheim and Tom Dirham of the Equity Engineering Group in carefully
documenting and checking the document is gratefully acknowledged.
Martin Prager
Executive Director
Welding Research Council
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
3
The Welding Research Council, Inc.
TABLE OF CONTENTS
1
2
3
4
5
6
7
8
9
10
11
Introduction ....................................................................................................................................7
Yield Strength .................................................................................................................................7
Ultimate Tensile Strength..............................................................................................................7
time-independent Allowable Stress .............................................................................................8
Larson-Miller Parameter ................................................................................................................8
time-dependent Allowable Stress ................................................................................................9
Rupture Exponent ..........................................................................................................................9
Applicable ASTM Specifications ................................................................................................10
Material Physical Properties .......................................................................................................10
Nomenclature ...............................................................................................................................10
Example Problems .......................................................................................................................11
11.1 Problem 1 – Calculate the minimum yield and the tensile strength at 400°F, for
2.25Cr-1Mo. .....................................................................................................................................11
11.2 Problem 2 – Determine the elastic design stress for 2.25 Cr-1Mo at 500°F. .................13
11.3 Problem 3 – Develop a plot of stress versus Larson-Miller Parameter (LMP) for
2.25Cr-1Mo. .....................................................................................................................................14
11.4 Problem 4 – Calculate the service life for 2.25Cr-1Mo at 975°F and 10 ksi stress using
the minimum and average Larson-Miller Parameters. ................................................................15
11.5 Problem 5 – Determine the service life for 2.25Cr-1Mo at 515°C and 100 MPa using the
minimum and average Larson-Miller Parameters. ......................................................................16
11.6 Problem 6 – Determine the Rupture Exponent, n , for 2.25 Cr-1Mo as a function of
temperature. ....................................................................................................................................17
11.7 Problem 7 – Develop a plot of stress verse service life for 2.25 Cr-1Mo at
temperatures of 1000°F and 1025°F based on the minimum Larson-Miller constant. ............19
11.8 Problem 8 – Determine the allowable design stress for 2.25 Cr-1Mo at 875°F for a
design life of 100,000 hours based on minimum properties. .....................................................21
11.9 Problem 9 – Determine the allowable design stress for 304L SS at 1050°F for a design
life of 100,000 hours based on minimum properties. .................................................................25
11.10 Problem 10 – Determine the allowable design stress for 347H SS at 1250°F for a
design life of 100,000 hours based on minimum properties. .....................................................27
11.11 Problem 11 – Develop a plot of service life as a function of stress and temperature for
2.25Cr-1Mo based on the minimum Larson-Miller Parameter. ..................................................29
11.12 Problem 12 – Develop a plot of rupture strength versus temperature for 2.25 Cr-1Mo
at a service life of 100,000 hours using both the average and minimum Larson-Miller
parameters. .....................................................................................................................................31
12 Tables ............................................................................................................................................33
13 Technical Basis ............................................................................................................................53
13.1 Overview ...............................................................................................................................53
13.2 Low Carbon Steel ................................................................................................................54
13.3 Medium Carbon Steel ..........................................................................................................58
13.4 C-0.5Mo .................................................................................................................................62
13.5 1.25Cr-0.5Mo ........................................................................................................................66
13.6 2.25Cr-1Mo ...........................................................................................................................70
13.7 3Cr-1Mo ................................................................................................................................74
13.8 5Cr-0.5Mo .............................................................................................................................78
13.9 5Cr-0.5Mo-Si.........................................................................................................................82
13.10 7Cr-0.5Mo .............................................................................................................................86
13.11 9Cr-1Mo ................................................................................................................................90
13.12 9Cr-1Mo-0.25V......................................................................................................................94
4
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.13
13.14
13.15
13.16
13.17
13.18
13.19
13.20
13.21
13.22
13.23
13.24
13.25
Type 304L Stainless Steel ..................................................................................................98
Type 304 & 304H Stainless Steel .....................................................................................102
Type 316L Stainless Steel ................................................................................................106
Type 316 & 316H Stainless Steel .....................................................................................110
Type 317L Stainless Steel ................................................................................................114
Type 321 Stainless Steel ...................................................................................................119
Type 321H Stainless Steel ................................................................................................123
Type 347 Stainless Steel ...................................................................................................127
Type 347H Stainless Steel ................................................................................................131
Alloy 800 .............................................................................................................................135
Alloy 800H ..........................................................................................................................139
Alloy 800HT ........................................................................................................................143
HK-40 ..................................................................................................................................147
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
5
The Welding Research Council, Inc.
ABSTRACT
Mechanical property data for alloys currently produced and used for petroleum refinery heater
applications have been gathered and analyzed using systematic computerized statistical data fitting
methods. Properties reported for each material are elevated temperature yield and tensile strength,
minimum and average stress-rupture strength and stress-rupture exponent at temperature. Data
gathered were representative of materials produced by modern production methods. The results of
the analyses were presented using polynomial equations for stress and temperature dependence of
the properties. Stress-rupture test results were used to develop Larson-Miller parameter relations
based on optimized constants for each alloy. Parameter plots for each alloy compare the properties
shown in API 530 with those obtained from the current analyses. Materials included are low and
medium carbon steels, carbon- 0.5mo steel, 1 ¼ Cr-1/2 Mo steel, 2 ¼ Cr-1 Mo, 3Cr-1 Mo steel and 5,
7 and 9 Cr-Mo steels , 9 Cr-1Mo-V steel, 304, 316, 317, 321 and 347 stainless steels (ordinary and H
grades where applicable), alloys 800, 800H and 800HT and HK-40. Examples are provided
demonstrating application of the polynomial equations to common problems such as determining
design life at temperature and design allowable stress.
6
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
1
INTRODUCTION
The materials data presented in this publication were obtained from materials produced more recently
than those used in preparing prior editions of API RP530 for the design of fired heater tubes. The
data for this project were gathered by the Materials Properties Council (MPC) under API contract from
test results for materials produced and tested at facilities not in the United States (US). The data
collections for prior editions of API RP 530 were limited to US sources. The new data for each alloy
were evaluated using modern computerized statistical regression methods and the results compared
graphically to the previously published properties. The coefficients for the polynomials resulting from
the regression analysis of the newer materials are presented in tabular form in this document to
facilitate computer implementation for design and life assessment.
The material data required for a design calculation in accordance with RP530/ISO 13704 are yield
strength, ultimate tensile strength, stress-rupture exponent, and minimum and average stress rupture
properties as described using Larson-Miller Parameter equations. This information is used to obtain
the time-independent or elastic allowable stress and the time-dependent or rupture allowable stresses
used in determining the required wall thickness of a fired heater tube or bend for a specified service
life and temperature.
The sections that follow immediately below describe each of the properties presented for each of the
materials. A series of examples in subsequent sections illustrate application of the analytical
equations used to represent the properties. The final sections of this report provide in tabular and
graphical form the yield strength, ultimate tensile strength, and the minimum and average stress
rupture properties. Comparisons of the properties determined under this project with those in the
prior edition of API RP530/ISO 13704 are shown.
2
YIELD STRENGTH
Equation (1) is used to represent the yield strength as a function of temperature. The coefficients for
use in this equation for each of the materials in API RP530/ISO 13704 are provided in Table 1.
(
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅ 10⎣
)
( ksi, F )
o
(1)
The yield strength at temperatures above room temperature may be calculated using this equation by
multiplying the yield strength value at room temperature by a temperature dependent ratio term. If
σ ysrt chosen for this equation is the specified minimum room temperature value of yield strength, then
the resulting value at a higher temperature can be taken as an estimate of the minimum value at that
temperature. If the average room temperature value of yield strength for a data set is used in
Equation(1), then the resulting value at the higher temperature can be taken as the best estimate of
the average value at that temperature. The ratios are deemed to be applicable over the range of
commonly provided and heat treatments and compositions for the respective materials.
3
ULTIMATE TENSILE STRENGTH
Equation (2) is in the same form as Equation (1) and is used to represent the ultimate tensile strength
as a function of temperature. The coefficients also are provided in Table 1.
(
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
rt
σ uts = σ uts
⋅ 10 ⎣
)
( ksi, F )
o
(2)
The ultimate tensile strength at temperatures above room temperature may be calculated using this
equation by multiplying the ultimate tensile strength value at room temperature by a temperature
dependent ratio term presented in the parenthesis. If the specified minimum room temperature value
of ultimate tensile strength is used in Equation (2), then the resulting value at temperature is an
estimate of the minimum value at a higher temperature. If the average room temperature value of
ultimate tensile strength of a data set is used in Equation (2), then at a higher temperature one
obtains an estimate of the corresponding average value.
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
7
The Welding Research Council, Inc.
4
TIME-INDEPENDENT ALLOWABLE STRESS
As shown in Table 2 and Equation (3), the time-independent or elastic allowable stress for each alloy
is proportional to the yield strength over a specific range of temperatures.
S e = Fed ⋅ σ ys
5
(3)
LARSON-MILLER PARAMETER
The Larson Miller Parameter (LMP) provides a relationship between stress, time to failure (taken here
to mean test, service or design life, Ld ,) and temperature. The basic expression for the Larson-Miller
Parameter is given by Equation (4) and Equation (7).
( hours, ksi, F )
LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])
o
(4)
Equations (5) and (6) are alternate forms of the same equation. In Equation (5) the test time, service
or designlife is shown as a function of applied stress and temperature. In Equation (6), the
temperature is a function of the applied stress and service life.
Ld = 10
T=
⎡ LMP (σ )
⎤
−C ⎥
⎢
⎢⎣ (T + 460 )
⎥⎦
( hours , ksi, F )
(5)
( hours, ksi, F )
(6)
o
LMP(σ )
− 460
( C + log10 [ Ld ])
o
The C coefficient in Equations (4), (5), and (6) is the Larson-Miller Constant. The Larson-Miller
constant has been optimized for each material in this study by statistical regression of the repective
test results using log time as the dependent variable and log stress and the reciprocal of the absolute
temperature as the independent variables. In MPC’s software a value of C is obtained for each lot
of material in the data set and then minimum and averages are computed. In Table 3 the somewhat
larger values shown the minimum constant entries are appropriate to represent the variance expected
at a 95% confidence interval.
In this document, the Larson-Miller Parameter for each material is presented as a polynomial in log10
of stress in the form given by Equation (7). The coefficients of Equation (7) for each material are
provided in Table 3. The Larson-Miller constant, C , applicable to the average and minimum
properties for each material is also shown in Table 3.
LMP = A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
3
(7)
The equations for the Larson-Miller Parameter should not be used for temperatures outside the
limiting metal temperature ranges shown for each material in Table 3.
Note that this treatment of the Larson-Miller Parameter is different from that in API RP530/ISO 13704
6th Edition. In that document, non-optimized Larson-Miller Constants are used for broad material
groups, C = 20 for ferrous materials and C = 15 for high alloy and nonferrous (high-nickel)
materials. Here alloy specific, optimized Larson-Miller Parameter constants are provided so that the
equations represent minimum and average behavior more precisely. Also, extrapolation of behavior
with temperature is sensitive to the constant used and the optimized constant should be used .
8
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
6
TIME-DEPENDENT ALLOWABLE STRESS
The time-dependent allowable stress, σ , may be determined from the Larson-Miller Parameter given
by Equation (7). The solution is given by Equation (8).
σ = 10− X
(8)
The exponent X in Equation (8) is computed exactly as follows based on the values of the
coefficients in Equation (7) as shown below for the cases where first, second and third order
polynomials were obtained for the stress dependence of the LMP..
a)
Case 1 – First order.
X =
b)
A1 is not equal to zero and A2 and A3 are equal to zero:
A0 − LMP
A1
(9)
Case 2 – second order (quadradic) polynomial.
A2 is not equal to zero, A3 is equal to zero, and
A1 can be any value including zero:
X=
c)
A1 + A12 − 4 A2 ( A0 − LMP )
2 A2
Case 3 – third order polynomial
(10)
A3 is not equal to zero, and A1 and A2 can be any values
including zero:
X =
A2
Q
−S−
3 A3
S
(11)
where,
2
⎛ A ⎞⎤
1 ⎡⎛ A2 ⎞
Q = ⎢⎜ ⎟ − 3 ⎜ 1 ⎟ ⎥
9 ⎢⎝ A3 ⎠
⎝ A3 ⎠⎥⎦
⎣
(12)
3
⎛A ⎞
⎛AA ⎞
⎛ A − LMP ⎞
2 ⎜ 2 ⎟ − 9 ⎜ 2 2 1 ⎟ + 27 ⎜ 0
⎟
A3 ⎠
A3 ⎠
A3
⎝
⎝
⎝
⎠
R=
54
(
⎛ R⎞
S = − ⎜⎜ ⎟⎟ R + R 2 − Q3
⎝ R⎠
7
)
1
3
(13)
(14)
RUPTURE EXPONENT
The rupture exponent can be obtained from the first derivative of log time with respect to stress at any
temperature. For the design calculation procedure in API RP530/ISO 13704 the rupture exponents
were determined between the 60,000-hour and 100,000-hour times for the minimum rupture
strengths determined from the Larson-Miller parameter curves. The following equation was used to
calculate for the rupture exponent, n , at various temperatures.
n=
log10 [100,000] − log [ 60,000]
log ⎡⎣ S100,000 ⎤⎦ − log ⎡⎣ S60,000 ⎤⎦
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
(15)
9
The Welding Research Council, Inc.
the values of the rupture exponents so obtained were fitted with up to a a fifth order polynomial as
shown in Equation (16). The resulting coefficients are presented in Table 4. It should be noted that
the r2 value for each fit was always very close to 1.
n = C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5
8
(16)
APPLICABLE ASTM SPECIFICATIONS
The applicable ASTM specifications for the generic material types that data are provided for are
shown in Table 5.
9
MATERIAL PHYSICAL PROPERTIES
Physical properties for materials that may be required in heat transfer and stress calculations (i.e.,
modulus of elasticity, thermal expansion coefficient, thermal conductivity, and thermal diffusivity) may
be obtained from WRC 503 for the materials covered in this document.
10 NOMENCLATURE
A0 → A5
coefficients used to determine the minimum and average Larson-Miller parameter as a
function of stress, as applicable.
C
Larson-Miller Constant, average or minimum value as applicable.
Cavg
Larson-Miller Constant, average properties.
Cmin
Larson-Miller Constant, minimum properties.
C0 → C5
coefficients used to determine the yield strength, ultimate tensile strength, and rupture
exponent as a function of temperature, as applicable.
Fed
elastic allowable stress design factor.
Ld
service or design life in hours.
LMP
n
Larson-Miller Parameter.
rupture exponent.
T
Temperature in degrees Fahrenheit.
S 60,000
stress to cause rupture in 60,000 hours.
S100,000
stress to cause rupture in 100,000 hours.
X
Q
time-independent allowable stress parameter.
R
time-independent allowable stress parameter.
S
σ
time-independent allowable stress parameter.
time-independent allowable stress parameter.
applied stress in ksi.
σ ys
yield stress in ksi.
σ uts
ultimate tensile strength in ksi.
σ ysrt
minimum specified yield strength in ksi at room temperature.
rt
σ uts
minimum specified ultimate tensile strength in ksi at room temperature.
10
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
11 EXAMPLE PROBLEMS
11.1 Problem 1 – Calculate the minimum yield and the tensile strength at 400°F, for 2.25Cr1Mo.
a)
STEP 1 – Obtain he minimum specified yield strength at room temperature from Table 1. Note
that this procedure is applicable to other room temperature strength values.
σ ysrt = 30 ksi
b)
(17)
STEP 2 – Determine the minimum yield strength at 400°F using Equations (1) and(18).
Equation (18) is also shown in the notes section of Table 1.
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅10 ⎣
The coefficients,
(18)
C0 through C5 for 2.25Cr-1Mo are determined from Table 1.
C0 = 2.1540371E-02
C1 = -3.2503600E-04
C2 = 2.2155200E-07
(19)
C3 = 4.1358400E-10
C4 = -6.4839900E-13
C5 = 1.5027000E-16
Substituting these values into Equation (18) results in:
σ ys = 26.032 ksi
(20)
or for a value in SI units:
⎛
MPa ⎞
σ ys = 26.032 ksi ⎜ 6.894757
⎟ = 179.5 MPa
ksi ⎠
⎝
c)
STEP 3 – Determine the minimum specified ultimate tensile strength at room temperature from
Table 1.
rt
σ muts
= 60 ksi
d)
(21)
(22)
STEP 4 – Determine the tensile strength at 400°F using Equations (2) and (23). Equation (23) is
also shown in the notes section of Table 1.
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
rt
σ uts = σ uts
⋅10⎣
The coefficients,
(23)
C0 through C5 for 2.25Cr-1Mo are determined from Table 1.
C0 = 1.4704266E-02
C1 = -1.9874800E-04
C2 = -2.9115300E-07
C3 = 2.0040500E-09
(24)
C4 = -2.2341400E-12
C5 = 5.9263200E-16
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
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The Welding Research Council, Inc.
Substituting these values into Equation (23) results in:
σ uts = 55.451 ksi
(25)
or for a value in SI units:
⎛
⎝
σ uts = 55.451 ksi ⎜ 6.894757
12
MPa ⎞
⎟ = 382.3 MPa
ksi ⎠
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
(26)
The Welding Research Council, Inc.
11.2 Problem 2 – Determine the elastic design stress for 2.25 Cr-1Mo at 500°F.
a)
STEP 1 – Determine the minimum specified yield strength at room temperature from Table 1.
σ ysrt = 30 ksi
b)
(27)
STEP 2 – Determine the yield strength at 500°F using Equation (28). This equation is also
shown in the notes section of Table 1.
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅10 ⎣
The coefficients,
(28)changed
C0 through C5 for 2.25Cr-1Mo are determined from Table 1.
C0 = 2.1540371E-02
C1 = -3.2503600E-04
C2 = 2.2155200E-07
C3 = 4.1358400E-10
(29)
C4 = -6.4839900E-13
C5 = 1.5027000E-16
Substituting these values into Equation (28) results in:
σ ys = 25.551 ksi
c)
STEP 3 – Determine the elastic allowable stress factor from Table 2.
Fed =
d)
(30)
2
3
(31)
STEP 4 – Determine the elastic allowable design stress.
⎛2⎞
S e = Fed ⋅ σ ys = ⎜ ⎟ ⋅ 25.551 ksi = 17.034 ksi
⎝3⎠
(32)
or in SI units:
⎛ 6.894757 MPa ⎞
S e = 17.034 ksi ⋅ ⎜
⎟ = 117.4 MPa
ksi
⎝
⎠
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
(33)
13
The Welding Research Council, Inc.
11.3 Problem 3 – Develop a plot of stress versus Larson-Miller Parameter (LMP) for 2.25Cr1Mo.
a)
STEP 1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equations (7) and (34). This equation is also shown in the notes section of Table 3, and can be
used for both average and minimum properties.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
The coefficients,
3
(34)
A0 through A3 for 2.25Cr-1Mo are determined from Table 3.
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(35)
A2 = 0.0
A3 = 0.0
b)
STEP 2 – Develop a table of stress versus the Larson-Miller Parameter, see Table 11.3E. Then
plot the Larson-Miller parameter on the x-axis and the stress on the y-axis, see Figure 11.3E.
Table 11.3E – Larson-Miller Parameter as a Function of Stress
Stress,
σ (ksi)
Larson Miller Parameter, LMP (x10-3)
1
5
10
15
20
25
30
35
40
43.946
38.082
35.556
34.079
33.031
32.218
31.553
30.992
30.505
Stress (ksi)
100
10
2.25Cr-1Mo
1
30
32
34
36
38
40
42
-3
LMP (x10 )
Figure 11.3E – Stress verse Larson-Miller Parameter
14
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
44
The Welding Research Council, Inc.
11.4 Problem 4 – Calculate the service life for 2.25Cr-1Mo at 975°F and 10 ksi stress using the
minimum and average Larson-Miller Parameters.
a)
STEP 1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equations (7) and (36). This equation is also shown in the notes section of Table 3, and can be
used for both average and minimum properties.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
(36)
The Larson-Miller constant, C , for minimum properties, and the coefficients
A0 through A3 for
2.25Cr-1Mo are determined from Table 3.
C = 1.9565607 E + 01
A0 = 4.3946400 E + 04
A1 = -8.3900000 E + 03
(37)
A2 = 0.0
A3 = 0.0
The Larson-Miller constant, C , for average properties, and the coefficients
A0 through A3 for
2.25Cr-1Mo are determined from Table 3. In this case, the parameter C is the only value that
differs between the minimum and average material properties. The Larson-Miller constant, C ,
for average properties is given by Equation (38).
C = 1.8918100E+01
b)
STEP 2 – The service life,
(38)
Ld , can be determined with the information in STEP 1 and Equation
(39), which is shown below.
Ld = 10
⎡ LMP (σ ) ⎤
−C ⎥
⎢
⎣⎢ (T + 460 )
⎦⎥
(39)
For a temperature and stress of 975°F and 10 ksi, the Larson-Miller Parameter and the
associated service life, Ld , based on minimum properties are:
LMP = 35556.4
(40)
Ld = 16069.3 hours
(41)
For a temperature and stress of 975°F and 10 ksi, the service life,
Ld , based on average
properties is:
Ld = 724234.3 hours
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
(42)
15
The Welding Research Council, Inc.
11.5 Problem 5 – Determine the service life for 2.25Cr-1Mo at 515°C and 100 MPa using the
minimum and average Larson-Miller Parameters.
a)
STEP 1 – Convert the temperature and stress to US Customary units.
T = 1.8 ( 515 o F ) + 32 = 959 o F
(43)
⎛
⎞
1 ksi
⎟ = 14.504 ksi
⎝ 6.894757 MPa ⎠
σ = 100 MPa ⋅ ⎜
b)
(44)
STEP 2 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equations (7) and (45). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
The Larson-Miller constant, C , for minimum properties, and the coefficients
(45)
A0 through A3 for
2.25Cr-1Mo are determined from Table 3.
C = 1.9565607E+01
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(46)
A2 = 0.0
A3 = 0.0
The Larson-Miller constant, C , for average properties, and the coefficients
A0 through A3 for
2.25Cr-1Mo are determined from Table 3. In this case, the parameter C is the only value that
differs between the minimum and average material properties. The Larson-Miller constant for
average properties, C , is given by Equation (38).
C = 1.8918100E+01
c)
STEP 3 – The service life,
(47)
Ld , can be determined with the information in STEP 1 and Equation
(48), which is shown below.
Ld = 10
⎡ LMP (σ ) ⎤
−C ⎥
⎢
⎣⎢ (T + 460 )
⎦⎥
(48)
For a temperature and stress of 515°C (959°F) and 100 MPa (14.393 ksi), the Larson-Miller
Parameter and service life, Ld , based on minimum properties is:
LMP = 34202
(49)
Ld = 34434 hours
(50)
For a temperature and stress of 515°C (959°F) and 100 MPa (14.393 ksi), the service life,
Ld ,
based on average properties is:
Ld = 152929 hours
16
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11.6 Problem 6 – Determine the Rupture Exponent, n , for 2.25 Cr-1Mo as a function of
temperature.
a)
STEP 1 – The equation for the Rupture Exponent, n as a function of temperature, T , is given
by Equations (16) and (52). This equation is also shown in the notes section of Table 4.
n = C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5
b)
STEP 2 – The coefficients,
(52)
C0 through C5 for 2.25Cr-1Mo are determined from Table 4.
C0 = 1.6116223E+01
C1 = -2.2988479E-02
C2 = 2.1835770E-05
(53)
C3 = -1.2833734E-08
C4 = 4.2012778E-12
C5 = -5.8449546E-16
c)
STEP 3 – Develop a table of the Rupture Exponent, n , verse temperature, T , using Equations
(52) and (53), see Table 11.6E. Then plot the temperature on the x-axis and the rupture
exponent on the y-axis, see Figure 11.6E.
Table 11.6E – Rupture Exponent as a Function of Temperature
Temperature,
800
850
900
950
1000
1050
1100
1150
1200
T ( oF )
Rupture Exponent, n
6.659
6.405
6.169
5.950
5.747
5.556
5.378
5.211
5.054
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Rupture Exponenet, n
7.0
6.5
6.0
5.5
2.25Cr-1Mo
5.0
800
850
900
950
1000
1050
1100
1150
Temperature (oF)
Figure 11.6E – Rupture Exponent as a Function of Temperature
18
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The Welding Research Council, Inc.
11.7 Problem 7 – Develop a plot of stress verse service life for 2.25 Cr-1Mo at temperatures
of 1000°F and 1025°F based on the minimum Larson-Miller constant.
a)
STEP 1 – The equation for the Larson-Miller Parameter as a function of stress, σ is given by
Equations (7) and (54). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
(54)
The Larson-Miller constant, C , for minimum properties, and the coefficients
A0 through A3 for
2.25Cr-1Mo are determined from Table 3.
C = 1.9565607E+01
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(55)
A2 = 0.0
A3 = 0.0
b)
STEP 2 – The service life,
Ld , can be determined with the information in STEP 1 and Equation
(56).
Ld = 10
⎡ LMP (σ ) ⎤
−C ⎥
⎢
⎣⎢ (T + 460 )
⎦⎥
(56)
Using Equations (54), (55), and (56), the Larson-Miller parameter and service life,
Ld , can be
computed as a function of stress. Data points for 2.25Cr-1Mo at 1000°F and 1025°F, based on
the minimum Larson-Miller parameter are shown in Table 11.7E. These data are subsequently
used to create the plot shown in Figure 11.7E.
Table 11.7E – Sample of Tabulated Values Used to Plot Figure 9.7E
Stress,
σ ( ksi )
Design Life,
LMP
Ld ( hours )
1000 o F
1025 o F
2
4.142E+04
6.3793E+08
2.1240E+08
4
3.890E+04
1.1882E+07
4.2305E+06
6
3.742E+04
1.1560E+06
4.2806E+05
8
3.637E+04
2.2131E+05
8.4260E+04
10
3.556E+04
6.1389E+04
2.3883E+04
12
3.489E+04
2.1531E+04
8.5258E+03
14
3.433E+04
8.8788E+03
3.5686E+03
16
3.384E+04
4.1219E+03
1.6782E+03
18
3.341E+04
2.0948E+03
8.6268E+02
20
3.303E+04
1.1434E+03
4.7569E+02
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Figure 11.7E – Rupture Stress as a Function of Temperature, Using the Minimum LMP
20
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11.8 Problem 8 – Determine the allowable design stress for 2.25 Cr-1Mo at 875°F for a design
life of 100,000 hours based on minimum properties.
a)
STEP 1 – Determine the allowable stress based on time-independent or elastic properties.
1) STEP 1.1 – Determine the minimum specified yield strength at room temperature from
Table 1.
2)
σ ysrt = 30 ksi
(57)
STEP 1.2 – Determine the yield strength at 875°F using Equations(1) and (58).
equation also appears in the notes section of Table 1.
This
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅10 ⎣
The coefficients,
(58)
C0 through C5 for 2.25Cr-1Mo are determined from Table 1.
C0 = 2.1540371E-02
C1 = -3.2503600E-04
C2 = 2.2155200E-07
(59)
C3 = 4.1358400E-10
C4 = -6.4839900E-13
C5 = 1.5027000E-16
Substituting these values in Equation (58) results in:
σ ys = 22.8005 ksi
3)
STEP 1.3 – Determine the elastic design factor from Table 2.
Fed =
4)
(60)
2
3
STEP 1.4 – Determine the allowable stress based on time-independent properties using
Equation (3), the elastic design stress.
⎛2⎞
S e = Fed ⋅ σ ys = ⎜ ⎟ ⋅ 22.8005 ksi = 15.2 ksi
⎝3⎠
b)
(61)
STEP 2 – Determine the allowable stress based on time-dependent properties.
1) STEP 2.1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equation (7) and (62). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
The Larson-Miller constant, C , for minimum properties, and the coefficients
(62)
A0 through
A3 for 2.25Cr-1Mo are determined from Table 3.
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C = 1.9565607E+01
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(63)
A2 = 0.0
A3 = 0.0
2)
STEP 2.2 – The larson-Miller parameter may be computed using Equation (4).
LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])
(64)
or,
LMP = ( 875 + 460 ) (19.565607 + log10 [100, 000 ]) = 32795
(65)
Using Equations (8) and (9), Case 1 in paragraph 6, from the procedure outlined in
paragraph 6.0 we have
X =
A0 − LMP ( 4.39464 E 4 − 32795 )
=
= −1.32912
A1
−8.39 E 3
St = σ = 10
− ( −1.32912 )
= 21.34 ksi
(66)
(67)
Equation (62) can be solved iteratively for the design stress, σ , which is the independent
variable in the Larson-Miller Parameter given by Equation (62), or by using a graphical
solution by constructing a plot of stress versus the Larson-Miller Parameter.
Data points for 2.25Cr-1Mo at 875°F based on the minimum Larson-Miller parameter are
shown in Table 11.8E. These data are subsequently used to create the plot shown in
Figure 11.8E. The stress corresponding to the Larson-Miller parameter given by (65) is:
St = 21.34 ksi
22
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Table 11.8E – Sample of Tabulated Values Used to Plot Figure 11.8E
LMP
Stress,
σ ( ksi )
32853
21.00
32844
21.05
32836
21.10
32827
21.15
32818
21.20
32810
21.25
32801
21.30
32795
21.336
32793
21.35
32784
21.40
32776
21.45
32767
21.50
32759
21.55
32750
21.60
32742
21.65
32734
21.70
32725
21.75
32717
21.80
32708
21.85
32700
21.90
32692
21.95
32683
22.00
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Stress (ksi)
100
10
1
30000
32000
34000
36000
38000
40000
42000
44000
LMP
c)
Figure 11.8E – Graphical Solution to Problem 8
STEP 3 – The allowable design stress is determined by taking the minimum value of the time
dependent and time independent stress values obtained from STEPS 1 and 2, respectively.
S = min [ S e , St ] = min [15.2 ksi, 21.34 ksi ] = 15.2 ksi
24
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11.9 Problem 9 – Determine the allowable design stress for 304L SS at 1050°F for a design
life of 100,000 hours based on minimum properties.
a)
STEP 1 – Determine the allowable stress based on time-independent or elastic properties.
1) STEP 1.1 – Determine the minimum specified yield strength at room temperature from
Table 1.
σ ysrt = 25 ksi
2)
(70)
STEP 1.2 – Determine the yield strength at 1050°F using Equations(1) and (58). This
equation also appears in the notes section of Table 1.
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅10 ⎣
The coefficients,
(71)
C0 through C5 for 304L SS are determined from Table 1.
C0 = 4.5888791E-02
C1 = -6.9508400E-04
C2 = 5.7950900E-07
(72)
C3 = -2.1178000E-10
C4 = 6.5466400E-15
C5 = -1.2730800E-17
Substituting these values in Equation (58) results in:
σ ys = 12.5732 ksi
3)
(73)
STEP 1.3 – Determine the elastic design factor from Table 2.
Fed = 0.9
4)
STEP 1.4 – Determine the allowable stress based on time-independent properties using
Equation (3), the elastic design stress.
S e = Fed ⋅ σ ys = ( 0.9 ) ⋅12.5732 ksi = 11.32 ksi
b)
(74)
STEP 2 – Determine the allowable stress based on time-dependent properties.
1) STEP 2.1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equation (7) and (62). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
3
The Larson-Miller constant, C , for minimum properties, and the coefficients
(75)
A0 through
A3 for 304L SS are determined from Table 3.
C = 1.8287902E+01
A0 = 4.6172960E+04
A1 = -8.4187000E+03
(76)
A2 = -1.4620000E+03
A3 = 0.0
2)
STEP 2.2 – The larson-Miller parameter may be computed using Equation (4).
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LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])
(77)
or,
LMP = (1050 + 460 ) (18.288 + log10 [100, 000 ]) = 35165
(78)
Using Equations (8) and (10), Case 2 in paragraph 6, from the procedure outlined in
paragraph 6.0 we have
-8.42E3 + (-8.42E3)2 − 4(-1.462E3)(46170 − 35165)
X=
= −1.09791
2(-1.462E3)
St = σ = 10
c)
− ( −1.09791)
= 12.529 ksi
(80)
STEP 3 – The allowable design stress is determined by taking the minimum value of the time
dependent and time independent stress values obtained from STEPS 1 and 2, respectively.
S = min [ S e , St ] = min [11.32 ksi, 12.53 ksi ] = 11.32 ksi
26
(79)
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11.10 Problem 10 – Determine the allowable design stress for 347H SS at 1250°F for a design
life of 100,000 hours based on minimum properties.
a)
STEP 1 – Determine the allowable stress based on time-independent or elastic properties.
1) STEP 1.1 – Determine the minimum specified yield strength at room temperature from
Table 1.
σ ysrt = 30 ksi
2)
(82)
STEP 1.2 – Determine the yield strength at 1250°F using Equations(1) and (58). This
equation also appears in the notes section of Table 1.
⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤
⎦
σ ys = σ ysrt ⋅10 ⎣
The coefficients,
(83)
C0 through C5 for 347H SS are determined from Table 1.
C0 = 4.9734437E-02
C1 = -8.6863733E-04
C2 = 2.5602354E-06
(84)
C3 = -4.5554196E-09
C4 = 3.7224192E-12
C5 = -1.0967259E-15
Substituting these values in Equation (58) results in:
σ ys = 19.3 ksi
3)
(85)
STEP 1.3 – Determine the elastic design factor from Table 2.
Fed = 0.9
4)
STEP 1.4 – Determine the allowable stress based on time-independent properties using
Equation (3), the elastic design stress.
S e = Fed ⋅ σ ys = 0.9 ⋅19.3 ksi = 17.4 ksi
b)
(86)
STEP 2 – Determine the allowable stress based on time-dependent properties.
1) STEP 2.1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equation (7) and (62). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
The Larson-Miller constant, C , for minimum properties, and the coefficients
(87)
A0 through
A3 for 347H SS are determined from Table 3.
C = 1.417E+01
A0 = 3.9536020E+04
A1 = -1.2225330E+04
(88)
A2 = 6.7502400E+03
A3 = -2.8722460E+03
2)
STEP 2.2 – The Larson-Miller parameter may be computed using Equation (4).
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LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])
(89)
or,
LMP = (1250 + 460 ) (14.17 + log10 [100, 000 ]) = 32781
(90)
Using Equations (8) and (11), Case 3 in paragraph 6, through (14) from the procedure
outlined in paragraph 6.0 we have
2
⎛ A ⎞⎤
1 ⎡⎛ A2 ⎞
Q = ⎢⎜ ⎟ − 3 ⎜ 1 ⎟ ⎥
9 ⎢⎝ A3 ⎠
⎝ A3 ⎠ ⎥⎦
⎣
2
⎛ -1.223 ×104 ⎞ ⎤
1 ⎡⎛ 6.75 ×103 ⎞
Q = ⎢⎜
⎟ − 3⎜
⎟⎥ = -0.8051
9 ⎢⎝ -2.87 ×103 ⎠
-2.872 ×103 ⎠ ⎥
⎝
⎣
⎦
(91)
3
⎛A ⎞
⎛AA ⎞
⎛ A − LMP ⎞
2 ⎜ 2 ⎟ − 9 ⎜ 2 2 1 ⎟ + 27 ⎜ 0
⎟
A3 ⎠
A3 ⎠
A3
⎝
⎝
⎝
⎠
R=
54
3
⎛ ⎛ 6.75 ×103 ⎞
⎡ 6.75 ×103 × -1.22 × 104 ⎤ ⎞
⎜ 2⎜
9
−
⎢
⎥ +⎟
3 ⎟
(-2.87 ×103 ) 2
⎜ ⎝ -2.87 × 10 ⎠
⎣
⎦ ⎟
⎜
⎟
4
⎜ 27 ⎡ 3.95 ×10 - ( 32781) ⎤
⎟
⎥
3
⎜ ⎢
⎟
×
-2.872
10
⎣
⎦
⎝
⎠ = 0.010465
R=
54
(
⎛ R ⎞
S = − ⎜⎜ ⎟⎟ R + R 2 − Q 3
⎝ R ⎠
)
1
3
(
⎛ 0.010465 ⎞
S = − ⎜⎜
⎟⎟ 0.010465 +
0.010465
⎝
⎠
c)
( 0.010465 )
2
− ( −0.8051)
X =
A2
Q
−S −
3 A3
S
X =
6.750 × 10 3
−0.8051
− (-0.90162) −
= -0.77472
3
3 × (-2.872 × 10 )
-0.90162
St = σ = 10
− ( -0.77472 )
3
)
1
3
= -0.90162
= 5.953 ksi
(93)
(94)
(95)
STEP 3 – The allowable design stress is determined by taking the minimum value of the time
dependent and time independent stress values obtained from STEPS 1 and 2, respectively.
S = min [ S e , St ] = min [17.3 ksi, 5.95 ksi ] = 5.95 ksi
28
(92)
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11.11 Problem 11 – Develop a plot of service life as a function of stress and temperature for
2.25Cr-1Mo based on the minimum Larson-Miller Parameter.
a)
STEP 1 – The relation for the Larson-Miller Parameter as a function of stress is given by
Equations (7) and (97). This equation is also shown in the notes section of Table 3.
LMP = A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
3
The Larson-Miller constant, C , for minimum properties, and the coefficients
(97)
A0 through A3 for
2.25Cr-1Mo are determined from Table 3.
C = 1.9565607E+01
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(98)
A2 = 0.0
A3 = 0.0
An equation that provides the service life as a function of stress and temperature can be
obtained by combining Equation (5) and Equation (97).
⎡ A + A ⋅log [σ ]+ A ⋅( log [σ ])2 + A ⋅( log [σ ])3 ⎤
2
10
3
10
⎢ 0 1 10
−C ⎥
⎢
⎥
T +460)
(
⎣
⎦
Ld = 10
b)
(99)
STEP 2 – Develop a table of the service life, Ld , for 20,000, 40,000, 60,000, and 100,000 hours
versus stress using Equation (99), see Table 11.9E. A plot of the service lives versus stress is
shown in Figure 11.9E.
Table 11.11E – ServiceTemperatures for indicated Service Lives
Stress,
σ ( ksi )
Service life , hours
20, 000
40, 000
60,000
100,000
5
1136
1116
1104
1090
10
1030
1011
1001
987
15
968
950
940
927
20
924
907
897
885
25
890
873
863
851
30
862
846
836
824
35
839
822
813
802
40
818
802
793
782
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Stress (ksi)
100
10
20,000 Hours
40,000 Hours
60,000 Hours
100,000 Hours
1
800
850
900
950
1000
1050
1100
1150
Temperature (oF)
Figure 11.1E – Service Life as a Function of Stress and Temperature
30
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11.12 Problem 12 – Develop a plot of rupture strength versus temperature for 2.25 Cr-1Mo at a
service life of 100,000 hours using both the average and minimum Larson-Miller
parameters.
a)
STEP 1 – The equation for the Larson-Miller Parameter as a function of stress is given by
Equations (7) and (100). This equation is also shown in the notes section of Table 3, and can be
used for both average and minimum properties.
LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ])
2
3
(100)
A0 through A3 for
The Larson-Miller constant, C , for minimum properties, and the coefficients
2.25Cr-1Mo are determined from Table 3.
C = 1.9565607E+01
A0 = 4.3946400E+04
A1 = -8.3900000E+03
(101)
A2 = 0.0
A3 = 0.0
The Larson-Miller constant, C , for average properties, and the coefficients
A0 through A3 for
2.25Cr-1Mo are determined from Table 3. However, C is the only value that is unique between
minimum and average parameters. The Larson-Miller constant for average properties, C , is
given by Equation (102).
C = 1.8918100E+01
(102)
An equation that provides the temperature as a function of stress and design life can be obtained
by combining Equation (6) and Equation (100).
A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
T (σ , Ld ) =
3
( C + log [ L ])
10
− 460
(103)
− 460
(104)
d
For 100,000 hours, Equation (104) becomes:
A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
T (σ , Ld ) =
3
( C + log [100, 000])
10
b)
STEP 2 – Develop a table of temperature versus stress based on the minimum and average
properties using Equation (104), see Table 11.12E. The data in this table are plotted in Figure
11.12E. In Table 11.12E, the temperatures in the column labeled Minimum Properties are
determined using Equation (104) with the Larson-Miller constant for minimum properties in
Equation (104), and the temperatures in the column labeled Average Properties are determined
using the Larson-Miller constant for average properties, or from Eqaution (104):
A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
T (σ , Ld )
minimum
properties
=
(C
min
+ log10 [100, 000])
A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ])
2
T (σ , Ld )
average
properties
=
3
(C
avg + log10 [100,000] )
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
− 460
(105)
− 460
(106)
3
31
The Welding Research Council, Inc.
Table 11.12E – Rupture Stress vs. Temperature for a Service Life of 100,000 Hours
Temperature,
σ ( ksi )
Stress,
T
( F)
o
Minimum Properties
Average Properties
5
1090
1132
10
987
1027
15
927
965
20
885
921
25
851
887
30
824
859
35
802
836
40
782
815
Stress (ksi)
100
10
Average LMP
Minimum LMP
1
800
850
900
950
1000
1050
1100
1150
1200
Temperature (oF)
Figure 11.12E – Rupture Stress vs. Temperature for a Service Life of 100,000 Hours
32
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
12 TABLES
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
26
47
C0
1.4088389E-02
1.0807518E-01
C1
-1.9932341E-04
-2.3290664E-03
C2
-2.0694516E-08
1.2941407E-05
C3
-1.0013720E-10
-2.6166794E-08
C4
0
2.2225699E-11
C5
0
-7.0569264E-15
σ rt
35
60
C0
1.4088389E-02
1.0807518E-01
C1
-1.9932341E-04
-2.3290664E-03
C2
-2.0694516E-08
1.2941407E-05
C3
-1.0013720E-10
-2.6166794E-08
C4
0
2.2225699E-11
C5
0
-7.0569264E-15
σ rt
30
52
C0
1.3089229E-02
1.1433749E-01
C1
-1.9903245E-04
-2.4719083E-03
C2
1.8433603E-07
1.3823832E-05
C3
-1.7552202E-10
-2.7995759E-08
C4
0
2.3927060E-11
C5
0
-7.5170846E-15
σ rt
30
60
C0
2.1540371E-02
1.4704266E-02
C1
-3.2503600E-04
-1.9874800E-04
C2
2.2155200E-07
-2.9115300E-07
C3
4.1358400E-10
2.0040500E-09
C4
-6.4839900E-13
-2.2341400E-12
C5
1.5027000E-16
5.9263200E-16
σ
Low Carbon Steel
Medium Carbon Steel
C-0.5Mo
1.25Cr-0.5Mo
rt
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
33
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
2.25Cr-1Mo
3Cr-1Mo
5Cr-0.5Mo
5Cr-0.5Mo-Si
34
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
30
60
C0
2.1540371E-02
1.4704266E-02
C1
-3.2503600E-04
-1.9874800E-04
C2
2.2155200E-07
-2.9115300E-07
C3
4.1358400E-10
2.0040500E-09
C4
-6.4839900E-13
-2.2341400E-12
C5
1.5027000E-16
5.9263200E-16
σ rt
30
60
C0
4.4186141E-02
4.3741544E-02
C1
-7.1542041E-04
-7.3028160E-04
C2
1.2664132E-06
1.6372698E-06
C3
-9.3458131E-10
-1.9656642E-09
C4
3.6214293E-13
1.2727055E-12
C5
-1.6088326E-16
-4.6917217E-16
σ rt
30
60
C0
1.2855425E-02
-1.5076613E-03
C1
-1.9373113E-04
1.6602155E-04
C2
1.2449247E-07
-2.4425324E-06
C3
3.0404621E-10
5.7486446E-09
C4
-3.5555955E-13
-4.9777060E-12
C5
-5.7953915E-18
1.3635365E-15
σ rt
30
60
C0
1.2855425E-02
-1.5076613E-03
C1
-1.9373113E-04
1.6602155E-04
C2
1.2449247E-07
-2.4425324E-06
C3
3.0404621E-10
5.7486446E-09
C4
-3.5555955E-13
-4.9777060E-12
C5
-5.7953915E-18
1.3635365E-15
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
7Cr-0.5Mo
9Cr-1Mo
9Cr-1Mo-V
Type 304L SS
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
30
60
C0
1.3532100E-01
9.9054977E-03
C1
-2.5870657E-03
-1.7559652E-04
C2
1.0664886E-05
5.5881927E-07
C3
-2.0092622E-08
-1.0648485E-09
C4
1.7366385E-11
5.6685649E-13
C5
-5.6740415E-15
-1.9197713E-16
σ rt
30
60
C0
1.3571242E-02
2.1597188E-02
C1
-1.7082315E-04
-3.1031668E-04
C2
-4.3400952E-07
-6.1394577E-08
C3
1.6036654E-09
1.3545273E-09
C4
-1.5678560E-12
-1.6448546E-12
C5
3.6386453E-16
4.1818392E-16
σ rt
60
85
C0
3.3650472E-02
1.8096292E-02
C1
-5.5446746E-04
-2.5065398E-04
C2
1.0944031E-06
-1.9394875E-07
C3
-5.7019722E-10
1.2610086E-09
C4
-1.9770030E-13
-1.3855450E-12
C5
0
3.4264520E-16
σ rt
25
70
C0
4.5888791E-02
7.7361661E-02
C1
-6.9508400E-04
-1.2718700E-03
C2
5.7950900E-07
2.4999900E-06
C3
-2.1178000E-10
-1.7023100E-09
C4
6.5466400E-15
1.2739600E-13
C5
-1.2730800E-17
7.2563700E-17
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
35
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
Type 304/304H SS
Type 316L SS
Type 316/316H SS
Type 317L SS
36
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
30
75
C0
9.8188514E-03
6.7196226E-02
C1
-5.0551619E-05
-1.1080527E-03
C2
-1.4866719E-06
2.2413756E-06
C3
3.0912775E-09
-1.8350694E-09
C4
-2.3688742E-12
5.9804933E-13
C5
6.0840262E-16
-1.2196459E-16
σ rt
25
70
C0
4.947300E-02
2.825000E-02
C1
-7.820685E-04
-3.814120E-04
C2
9.205307E-07
-1.664940E-07
C3
-9.753774E-10
1.406040E-09
C4
7.836576E-13
-1.341640E-12
C5
-2.709835E-16
3.241850E-16
σ rt
30
75
C0
1.2001323E-02
3.2859229E-02
C1
-8.8000344E-05
-5.1714106E-04
C2
-1.5040192E-06
4.6118780E-07
C3
3.1425000E-09
6.1438157E-10
C4
-2.4201238E-12
-9.2054227E-13
C5
6.4067530E-16
2.2901104E-16
σ rt
25
70
C0
4.947300E-02
2.825000E-02
C1
-7.820685E-04
-3.814120E-04
C2
9.205307E-07
-1.664940E-07
C3
-9.753774E-10
1.406040E-09
C4
7.836576E-13
-1.341640E-12
C5
-2.709835E-16
3.241850E-16
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
Type 321 SS
Type 321H SS
Type 347 SS
Type 347H SS
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
30
75
C0
6.863218E-02
6.278852E-02
C1
-1.184702E-03
-1.080116E-03
C2
3.244156E-06
2.863153E-06
C3
-4.905795E-09
-3.697114E-09
C4
3.536365E-12
2.478506E-12
C5
-9.654898E-16
-7.256524E-16
σ rt
25
70
C0
1.0112716E-02
5.1423451E-02
C1
-1.4446737E-04
-8.3118863E-04
C2
0
1.4451218E-06
C3
0
-9.5441766E-10
C4
0
2.5659891E-13
C5
0
-8.2941763E-17
σ rt
30
75
C0
4.9734437E-02
6.9844688E-02
C1
-8.6863733E-04
-1.2173646E-03
C2
2.5602354E-06
3.4825694E-06
C3
-4.5554196E-09
-5.2044883E-09
C4
3.7224192E-12
3.8869832E-12
C5
-1.0967259E-15
-1.1567466E-15
σ rt
30
75
C0
4.9734437E-02
6.9844688E-02
C1
-8.6863733E-04
-1.2173646E-03
C2
2.5602354E-06
3.4825694E-06
C3
-4.5554196E-09
-5.2044883E-09
C4
3.7224192E-12
3.8869832E-12
C5
-1.0967259E-15
-1.1567466E-15
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
37
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
Alloy 800
Alloy 800H
Alloy 800HT
38
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
30
75
C0
3.4030711E-02
3.4512216E-02
C1
-5.9044935E-04
-6.1931709E-04
C2
1.6819983E-06
2.0239806E-06
C3
-2.9084079E-09
-3.3262726E-09
C4
2.4078033E-12
2.7021246E-12
C5
-7.5887806E-16
-8.8727065E-16
σ rt
25
65
C0
9.1352894E-03
8.4274949E-04
C1
-6.7153045E-05
8.2765885E-05
C2
-1.0330418E-06
-1.5893549E-06
C3
1.9114308E-09
3.5471048E-09
C4
-1.1936454E-12
-2.7606359E-12
C5
2.1862178E-16
6.5642052E-16
σ rt
25
65
C0
3.4727533E-02
9.1734120E-03
C1
-5.3949644E-04
-4.3023314E-05
C2
6.3686186E-07
-1.5560083E-06
C3
-2.3816323E-10
4.5571519E-09
C4
-7.1132721E-14
-4.2665496E-12
C5
-4.2576695E-18
1.1882810E-15
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F)
Material
HK-40
Parameter
Yield Strength (ksi)
Tensile Strength (ksi)
σ rt
35
62
C0
4.3689351E-03
4.7208139E-03
C1
4.5144996E-05
-1.3979452E-07
C2
-1.7279747E-06
-1.1239086E-06
C3
2.8459599E-09
2.4482148E-09
C4
-1.6093404E-12
-1.8461449E-12
C5
2.7808712E-16
4.2367166E-16
Notes:
1. In the parameter column, the term
yield strength,
σ rt
is used to represent the room temperature value of the
rt
.
σ ysrt , and the room temperature value of the ultimate tensile strength, σ uts
2. The yield strength as a function of temperature is computed using Equation (1).
3. The tensile strength as a function of temperature is computed using Equation (2).
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
39
The Welding Research Council, Inc.
Table 2 – Elastic Allowable Stress Factor and Applicable Temperature Range
Elastic Allowable
Stress Design Factor
Material
Applicable Temperature Range (°F)
Fed
Minimum
Maximum
Low Carbon Steel
2/3
70
1000
Medium Carbon Steel
2/3
70
1000
C-0.5Mo
2/3
70
1050
1.25Cr-0.5Mo
2/3
70
1200
2.25Cr-1Mo
2/3
70
1200
3Cr-1Mo
2/3
70
1200
5Cr-0.5Mo
2/3
70
1200
5Cr-0.5Mo-Si
2/3
70
1200
7Cr-0.5Mo
2/3
70
1200
9Cr-1Mo
2/3
70
1300
9Cr-1Mo-V
2/3
70
1300
Type 304L SS
0.9
70
1500
Type 304/304H SS
0.9
70
1500
Type 316L SS
0.9
70
1500
Type 316/316H SS
0.9
70
1500
Type 317L SS
0.9
70
1500
Type 321 SS
0.9
70
1500
Type 321H SS
0.9
70
1500
Type 347 SS
0.9
70
1500
Type 347H SS
0.9
70
1500
Alloy 800
0.9
70
1500
Alloy 800H
0.9
70
1650
Alloy 800HT
0.9
70
1850
HK-40
0.9
70
1850
40
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress
Material
Parameter
Temperature Range (˚F)
C
Low Carbon Steel
700-1000
1.8150000E+01
3.5093240E+04
A1
-3.6037901E+03
A2
-1.9136590E+03
A3
-250
Temperature Range (˚F)
700-1000
1.5600000E+01
3.2068370E+04
A1
-3.3755550E+03
A2
-1.5933910E+03
A3
-3.0000000E+02
C
1.8725370E+01
3.8792100E+04
A1
-4.9502240E+03
A2
0
A3
0
Temperature Range (˚F)
800-1200
22.054
21.558
A0
4.6354380E+04
A1
-6.9466030E+03
A2
-3.4367510E+02
A3
0
Temperature Range (˚F)
800-1200
C
2.25Cr-1Mo
700-1050
1.9007756E+01
A0
C
1.25Cr-0.5Mo
1.5150000E+01
A0
Temperature Range (˚F)
C-0.5 Mo
1.7700000E+01
A0
C
Medium Carbon
Steel
Larson-Miller
Constant and
Parameter vs.
Stress: Average
Properties
Larson-Miller
Constant and
Parameter vs. Stress:
Minimum Properties
1.9565607E+01
1.8918100E+01
A0
4.3946400E+04
A1
-8.3900000E+03
A2
0
A3
0
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
41
The Welding Research Council, Inc.
Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress
Material
Parameter
Temperature Range (˚F)
3Cr-1Mo
5Cr-0.5Mo
C
900-1200
1.5785226E+01
1.5381060E+01
A0
3.7264510E+04
A1
-7.9439300E+03
A2
0
A3
0
Temperature Range (˚F)
C
900-1200
1.6025829E+01
1.5589280E+01
A0
3.7264510E+04
A1
-7.9439300E+03
A2
0
A3
0
Temperature Range (˚F)
C
5Cr-0.5Mo-Si
7Cr-0.5Mo
42
900-1200
1.6025829E+01
1.5589280E+01
A0
3.7264510E+04
A1
-7.9439300E+03
A2
0
A3
0
Temperature Range (˚F)
C
900-1200
2.0437460E+01
1.9620550E+01
A0
4.5219510E+04
A1
-1.0217000E+04
A2
5.2679960E+00
A3
-6.3855690E+00
Temperature Range (˚F)
900-1300
C
9Cr-1Mo
Larson-Miller
Constant and
Parameter vs.
Stress: Average
Properties
Larson-Miller
Constant and
Parameter vs. Stress:
Minimum Properties
2.6223587E+01
2.5859090E+01
A0
5.4758000E+04
A1
-6.1891000E+03
A2
-1.7309000E+03
A3
-6.7715000E+02
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress
Material
Parameter
Temperature Range (˚F)
9Cr-1Mo-V
Type 304L SS
C
900-1300
3.0886006E+01
3.0364230E+01
A0
6.3450000E+04
A1
-1.3800000E+03
A2
-5.1395320E+03
A3
0
Temperature Range (˚F)
C
900-1500
1.8287902E+01
1.7550000E+01
A0
4.6172960E+04
A1
-8.4187000E+03
A2
-1.4620000E+03
A3
0
Temperature Range (˚F)
C
Type 304/304H SS
Type 316L SS
1000-1500
1.6145903E+01
1.5521950E+01
A0
4.3539460E+04
A1
-9.7318000E+03
A2
0
A3
0
Temperature Range (˚F)
C
900-1500
1.5740107E+01
1.5200000E+01
A0
4.1483380E+04
A1
-6.0606000E+03
A2
-1.7620000E+03
A3
0
Temperature Range (˚F)
1000-1500
C
Type 316/316H SS
Larson-Miller
Constant and
Parameter vs.
Stress: Average
Properties
Larson-Miller
Constant and
Parameter vs. Stress:
Minimum Properties
1.6764145E+01
1.6309870E+01
A0
4.4933830E+04
A1
-9.4286740E+03
A2
0
A3
0
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
43
The Welding Research Council, Inc.
Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress
Material
Parameter
Temperature Range (˚F)
Type 317L SS
C
900-1500
1.5740107E+01
1.5200000E+01
A0
4.1483380E+04
A1
-6.0606000E+03
A2
-1.7620000E+03
A3
0
Temperature Range (˚F)
900-1500
C
Type 321 SS
1.332500E+01
3.571361E+04
A1
-5.655000E+03
A2
-7.640000E+02
A3
0
C
Type 347 SS
44
900-1500
1.5293986E+01
1.4759580E+01
A0
4.0541580E+04
A1
-6.5212870E+03
A2
-9.7543650E+02
A3
0
Temperature Range (˚F)
C
900-1500
1.4889042E+01
1.4250000E+01
A0
3.7960000E+04
A1
-7.1172160E+03
A2
3.1133520E+03
A3
-2.3000000E+03
Temperature Range (˚F)
900-1500
C
Type 347H SS
1.280000E+01
A0
Temperature Range (˚F)
Type 321H SS
Larson-Miller
Constant and
Parameter vs.
Stress: Average
Properties
Larson-Miller
Constant and
Parameter vs. Stress:
Minimum Properties
14.17
13.65
A0
3.9536020E+04
A1
-1.2225330E+04
A2
6.7502400E+03
A3
-2.8722460E+03
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress
Material
Parameter
Temperature Range (˚F)
Alloy 800
C
900-1500
1.7005384E+01
1.6508780E+01
A0
4.3171030E+04
A1
-8.1470000E+03
A2
0
A3
0
Temperature Range (˚F)
1000-1650
C
Alloy 800H
1.6042270E+01
4.5864990E+04
A1
-9.2709340E+03
A2
-1.9293220E+03
A3
7.0913170E+02
C
HK-40
1.6564046E+01
A0
Temperature Range (˚F)
Alloy 800HT
Larson-Miller
Constant and
Parameter vs.
Stress: Average
Properties
Larson-Miller
Constant and
Parameter vs. Stress:
Minimum Properties
900-1850
1.3606722E+01
1.3234100E+01
A0
4.0112700E+04
A1
-9.0816690E+03
A2
0
A3
0
Temperature Range (˚F)
C
1400-1850
1.0856489E+01
1.0489900E+01
A0
3.4132000E+04
A1
-7.7078820E+03
A2
-9.4500000E+02
A3
0
Note: The average and minimum Larson-Miller Parameter is computed using Equation (7) with the
appropriate coefficients from this table.
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
45
The Welding Research Council, Inc.
Table 4 – Rupture Exponents as a Function of Temperature
Material
Low Carbon Steel
Medium Carbon Steel
C-0.5 Mo
1.25Cr-0.5Mo
46
Parameter
Rupture Exponent – n
Temperature Range (˚F)
700-1000
C0
2.3405940E+01
C1
-2.4087544E-02
C2
4.4283728E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
700-1000
C0
2.9832967E+01
C1
-4.8908169E-02
C2
3.3126428E-05
C3
-1.0132081E-08
C4
0
C5
0
Temperature Range (˚F)
700-1050
C0
8.98300
C1
-1.1316171E-02
C2
9.0861459E-06
C3
-4.3999472E-09
C4
1.1678546E-12
C5
-1.3028530E-16
Temperature Range (˚F)
800-1200
C0
1.7939223E+01
C1
-2.6358008E-02
C2
2.2487501E-05
C3
-1.1762993E-08
C4
3.3765405E-12
C5
-4.1070388E-16
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 4 – Rupture Exponents as a Function of Temperature
Material
2.25Cr-1Mo
3Cr-1Mo
5Cr-0.5Mo
5Cr-0.5Mo-Si
Parameter
Rupture Exponent – n
Temperature Range (˚F)
800-1200
C0
1.6116223E+01
C1
-2.2988479E-02
C2
2.1835770E-05
C3
-1.2833734E-08
C4
4.2012778E-12
C5
-5.8449546E-16
Temperature Range (˚F)
800-1200
C0
1.1607134E+01
C1
-8.5353735E-03
C2
2.3722609E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
800-1200
C0
1.1770651E+01
C1
-8.8389784E-03
C2
2.5108933E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
800-1200
C0
1.1770651E+01
C1
-8.8389784E-03
C2
2.5108933E-06
C3
0
C4
0
C5
0
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The Welding Research Council, Inc.
Table 4 – Rupture Exponents as a Function of Temperature
Material
7Cr-0.5Mo
9Cr-1Mo
9Cr-1Mo-V
Type 304LS
48
Parameter
Rupture Exponent – n
Temperature Range (˚F)
900-1200
C0
1.4536269E+01
C1
-1.0232458E-02
C2
2.7034326E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
900-1300
C0
4.04893689E+01
C1
-4.58475585E-02
C2
1.52674903E-05
C3
-1.35165711E-09
C4
0
C5
0
Temperature Range (˚F)
900-1300
C0
3.1524887E+03
C1
-1.4781109E+01
C2
2.7852967E-02
C3
-2.6205892E-05
C4
1.2291955E-08
C5
-2.2995921E-12
Temperature Range (˚F)
900-1500
C0
3.8310366E+01
C1
- 7.6035759E-02
C2
8.5397605E-05
C3
- 5.5768707E-08
C4
1.9173301E-11
C5
-2.7104077E-15
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
Table 4 – Rupture Exponents as a Function of Temperature
Material
Type 304/304H SS
Type 316L SS
Type 316/316H SS
Type 317L SS
Parameter
Rupture Exponent – n
Temperature Range (˚F)
1000-1500
C0
1.3035950E+01
C1
-8.3130608E-03
C2
1.9505879E-06
C3
0
C4
0
C5
0
Temperature Range
900-1500
C0
3.1313017E+01
C1
-5.3186547E-02
C2
5.3079687E-05
C3
-3.3897226E-08
C4
1.2195544E-11
C5
-1.9272376E-15
Temperature Range (˚F)
1000-1500
C0
1.2629907E+01
C1
-8.0541256E-03
C2
1.8898310E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
900-1500
C0
3.1313017E+01
C1
-5.3186547E-02
C2
5.3079687E-05
C3
-3.3897226E-08
C4
1.2195544E-11
C5
-1.9272376E-15
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The Welding Research Council, Inc.
Table 4 – Rupture Exponents as a Function of Temperature
Material
Type 321 SS
Type 321H SS
Type 347 SS
Type 347H SS
50
Parameter
Rupture Exponent – n
Temperature Range (˚F)
900-1500
C0
1.645017E+01
C1
- 1.766063E-02
C2
8.225988E-06
C3
-1.612134E-09
C4
0
C5
0
Temperature Range (˚F)
1000-1500
C0
1.5128673E+01
C1
-1.0738718E-02
C2
2.0390552E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
900-1500
C0
1.105274E+01
C1
4.019553E-02
C2
-6.916989E-05
C3
2.599652E-08
C4
0
C5
0
Temperature Range (˚F)
900-1500
C0
2.6091589E+02
C1
- 1.0769332E+00
C2
1.9246050E-03
C3
- 1.7559313E-06
C4
7.9665773E-10
C5
-1.4196157E-13
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
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Table 4 – Rupture Exponents as a Function of Temperature
Material
Alloy 800
Alloy 800H
Alloy 800HT
HK-40
Parameter
Rupture Exponent – n
Temperature Range (˚F)
900-1500
C0
1.4784080E+01
C1
-1.8623974E-02
C2
1.4953835E-05
C3
-7.2413632E-09
C4
1.9220365E-12
C5
-2.1442147E-16
Temperature Range (˚F)
1100-1650
C0
6.9797821E+00
C1
2.5834678E-03
C2
-2.4115193E-06
C3
0
C4
0
C5
0
Temperature Range (˚F)
900-1850
C0
1.5182940E+01
C1
-1.5959900E-02
C2
9.6990330E-06
C3
-3.1060390E-09
C4
4.0509520E-13
C5
0
Temperature Range (˚F)
1400-1850
C0
1.4332073E+01
C1
-9.2105347E-03
C2
1.7274314E-06
C3
0
C4
0
C5
0
Note: The average and minimum Larson-Miller Parameter is computed using Equation (16) with
the appropriate coefficients from this table.
WRC Bulletin 541
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The Welding Research Council, Inc.
Table 5 – Material Designation and Applicable ASTM Specifications
Material
Applicable ASTM Specifications
Low Carbon Steel
A161, A192
Medium Carbon Steel
C-0.5Mo
A161 T1, A209 T1 A335 P1
1.25Cr-0.5Mo
A213 T11, A335 P11, A200 T11
2.25Cr-1Mo
A213 T22, A335 P22, A200 T22
3Cr-1Mo
A213 T21, A335 P21, A200 T21
5Cr-0.5Mo
A213 T5, A335 P5, A200 T5
5Cr-0.5Mo-Si
A213 T5b, A335 P5b
7Cr-0.5Mo
A213 T7, A335 P7, A200 T7
9Cr-1Mo
A213 T9, A335 P9, A200 T9
9Cr-1Mo-V
52
A53 Grade B (seamless), A106 Grade B, A210 Grade A-1
A213 T91, A335 P91, A200 T91
Type 304L SS
A213 Type 304L, A271 Type 304L, A312 Type 304L, A 376 Type
304L
Type 304/304H SS
A213 Type 304, A271 Type 304, A312 Type 304, A 376 Type 304
A213 Type 304H, A271 Type 304H, A312 Type 304H, A 376 Type
304H
Type 316L SS
A213 Type 316L, A271 Type 316L, A312 Type 316L, A 376 Type
316L
Type 316/316H SS
A213 Type 316, A271 Type 316, A312 Type 316, A 376 Type 316
A213 Type 316H, A271 Type 316H, A312 Type 316H, A 376 Type
316H
Type 317L SS
A213 Type 317L, A312 Type 317L
Type 321 SS
A213 Type 321, A271 Type 321, A312 Type 321, A 376 Type 321
Type 321H SS
A213 Type 321H, A271 Type 321H, A312 Type 321H, A 376 Type
321H
Type 347 SS
A213 Type 347, A271 Type 347, A312 Type 347, A 376 Type 347
Type 347H SS
A213 Type 347H, A271 Type 347H, A312 Type 347H, A 376 Type
347H
Alloy 800
B407 UNS N08800
Alloy 800H
B407 UNS N08810
Alloy 800HT
B407 UNS N08811
HK-40
A608 Grade HK-40
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13
TECHNICAL BASIS
13.1 Overview
For each of the materials included in this document, the following four graphs are provided.
a) Yield and ultimate tensile strength as a function of temperature. Values for the yield and ultimate
tensile strength as a function of temperature are based on new test results above room temperature
and are anchored to the specified minimum yield and ultimate tensile strength properties at room
temperature. The new values shown are compared to the elevated temperature values given for the
yield and ultimate tensile strength in RP530/ISO 13704, Revision 6. Note the elevated temperature
values in RP530/ISO 13704, Revision 6 are anchored at 300°F or 400°F depending on the material.
b) The average and minimum stress rupture strengths as functions of the Larson-Miller Parameter. The
proposed relationship between rupture stress for minimum and the average materials are presented
using optimized Larson-Miller Parameter constants based on recent analysis of material properties
for virgin materials. The new parameter curves are shown and compared to the curves given in
RP530/ISO 13704, Revision 6. Note that presentation using separate curves for average and
minimum properties follows the presentation of stress rupture design curves in RP530/ISO 13704,
Revision 6 where separate curves for average and minimum properties are provided for use with a
single Larson-Miller constant that depends on the class of material, usually 15 or 20. For the new
plots when using the average and minimum curves for computations, the optimized average LarsonMiller Constant from Table 3 is used to adjust all the lines so they may be compared. The test
results used to calculate the proposed curves are shown on these plots. Again they are calculated
using the optimized average constant in each case. Properties for service-exposed materials were
not included at the specific directive of the API committee which cited the historical use of only virgin
(unexposed) material in assembling the property data base. Thus, the Larson-Miller Parameter
equations and constants provided herein are not the identical to those for the same materials as
presented in API 579-1/ASME FFS-1 on fitness-for-service. Equations presented for use in
determining fitness-for-service of service-exposed materials were established by testing materials as
near as possible to design level stresses and temperatures with an emphasis on identifying creep
strain rates and a creep damage parameter referred to as Omega, see API 579-1/ASME FFS-1, for
the properties developed under service conditions. Changes in materials during service affect both
the time-dependent and time-independent properties, identified in item a) above, of these materials.
Additionally, the materials properties for the MPC Omega Method found in API 579-1/ASME FFS-1
were not intended to and do not represent material behavior at stresses and temperatures outside
the range of design conditions.
c) Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units.
A single curve is provided for the relationship between stress and Larson-Miller parameter. The
differentiation between minimum and average time-dependent properties is accounted for by using
the respective Larson-Miller Constants shown on each plot; Cmin to calculate the minimum properties
and Cavg to calculate average properties.
d) Rupture Exponent versus Temperature A plot of rupture exponent versus temperature is provided
for each material. The rupture exponent is the slope of the (log) time vs. (log) rupture stress relation
at a particular time specified by API. For most materials then, this plot is a shows a slope changing
with temperature and usually decreasing with increasing temperature (decreasing stress). This is
expected if a Larsen-Miller parameter is used for correlating data since absolute temperature
appears in the denominator of the terms in the slope defining equation.
However, the microstructures of some of the alloys vary with temperature and the ruptureexponent
may increase or decrease with increasing temperature. The same may be true of ductility. To
capture this variable relation between creep rate and ductility second or third order polynomials are
needed to describe the shape of the parameter plot. The rupture exponent then may be a second
order polynomial which may show inflections, minima (or even a maxima) in the range of interest.
The microstructure /temperature changes that lead to an inflection in the rupture exponent curves at
the time specified by API can be seen in the plots for Type 347 SS, Type 347H SS, Alloy 800H and
Alloy 800 HT. There is nothing in nature to preclude that possibility.
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
53
The Welding Research Council, Inc.
13.2 Low Carbon Steel
The data base compiled was limited to tubular components and the typical low tensile strengths
associated with normal heat treatments. For this study test results at very high stresses were eliminated
to avoid imposing unfounded curvature on predicted low stress behavior. The resulting database was
well fit by a linear expression, but the scatter is undeniable. The current use of a Larson Miller constant
of 20 in API 530, Revision 6 in comparison to the appropriate value in the range of 17-19 results in too
high design stresses when test results are extrapolated to typical carbon steel operating temperatures.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
TEMPERATURE, F
Figure 13.2-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Low Carbon Steel
54
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.2-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Low Carbon Steel
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100
Cavg = 17.70
Cmin= 18.15
S
T
R
E
S
S 10
,
K
s
i
1
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.2-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Low Carbon Steel
56
WRC Bulletin 541
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9.00
RUPTURE EXPONENT, n
8.00
7.00
6.00
5.00
4.00
3.00
700
750
800
850
900
950
1000
TEMPERATURE, F
Figure 13.2-4: Rupture Exponent as a Function of Temperature: Low Carbon Steel
WRC Bulletin 541
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The Welding Research Council, Inc.
13.3 Medium Carbon Steel
As with low carbon materials the Larson Miller constant is well below 20 and results in more conservative
stresses at expected operating temperatures as compared to the current document. The data used in the
analysis was mostly from overseas sources for tubular products. Within this data set a clear beneficial
effect of molybdenum on strength is seen at levels of only 0.005, 0.01 and 0.02% Mo. Data on heats with
higher Mo content was typically eliminated because of its strong biasing effect.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
TEMPERATURE, F
Figure 13.3-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Medium Carbon Steel
58
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
20
22
24
26
28
30
32
LARSON‐MILLER PARAMETER/1000
Figure 13.3-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Medium Carbon Steel
WRC Bulletin 541
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The Welding Research Council, Inc.
100
Cavg = 15.15
Cmin= 15.6
S
T
R
E
S
S 10
,
K
s
i
1
20
22
24
26
28
30
32
LARSON‐MILLER PARAMETER/1000
Figure 13.3-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Medium Carbon Steel
60
WRC Bulletin 541
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9.00
RUPTURE EXPONENT, n
8.00
7.00
6.00
5.00
4.00
3.00
700
750
800
850
900
950
1000
TEMPERATURE, F
Figure 13.3-4: Rupture Exponent as a Function of Temperature: Medium Carbon Steel
WRC Bulletin 541
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The Welding Research Council, Inc.
13.4 C-0.5Mo
Data for the very high stresses at which this strong alloy can be tested were eliminated because, absent
data at low, realistic design level stresses, the polynomial fit would tend to show an inflection and
nonconservative strength values at design levels. The resulting design lines from this analysis do not
differ much from the current API 530 values. However, there is very little foundation for the design
stresses at temperatures much above 950 F.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.4-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: C-0.5Mo
62
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.4-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: C-0.5Mo
WRC Bulletin 541
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The Welding Research Council, Inc.
100
Cavg = 18.72537
Cmin= 19.007756
S
T
R
E
S
S 10
,
K
s
i
1
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.4-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: C-0.5Mo
64
WRC Bulletin 541
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The Welding Research Council, Inc.
4.60
4.40
RUPTURE EXPONENT, n
4.20
4.00
3.80
3.60
3.40
3.20
3.00
700
750
800
850
900
950
1000
1050
TEMPERATURE, F
Figure 13.4-4: Rupture Exponent as a Function of Temperature: C-0.5Mo
WRC Bulletin 541
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The Welding Research Council, Inc.
13.5 1.25Cr-0.5Mo
Most prior curves in API 530 were taken from Smith's work for MPC in the 60's and 70's. For this material
new data were obtained primarily from Japan. The superior behavior predicted at low stresses is based
on MPC's Project Omega studies in which the material did not suffer from severe oxidation in tests at
temperatures used in the low stress range. The trends are demonstrated by the equations and
coefficients found in Annex F of API 579-1/ASME FFS-1. These validate the more linear curve shape for
these low alloy steels.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.5-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 1.25Cr-0.5Mo
66
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.5-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 1.25Cr-0.5Mo
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100
Cavg = 21.387
Cmin= 21.891803
S
T
R
E
S
S 10
,
K
s
i
1
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.5-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 1.25Cr-0.5Mo
68
WRC Bulletin 541
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7.00
RUPTURE EXPONENT, n
6.50
6.00
5.50
5.00
4.50
4.00
800
850
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.5-4: Rupture Exponent as a Function of Temperature: 1.25Cr-0.5Mo
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13.6 2.25Cr-1Mo
Most prior curves in API 530 were taken from Smith's work for MPC in the 60's and 70's. New data were
obtained primarily from Japan. The superior behavior predicted at low stresses is based on MPC's
Project Omega studies, in which the tested material did not suffer from severe oxidation in tests at
temperatures used in the low stress range. The trends are demonstrated by the equations and
coefficients found in Annex F of API 579-1/ASME FFS-1. These validate the more linear curve shape for
these low alloy steels.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.6-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 2.25Cr-1Mo
70
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.6-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 2.25Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
71
The Welding Research Council, Inc.
100
Cavg = 18.9181
Cmin= 19.565607
S
T
R
E
S
S 10
,
K
s
i
1
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.6-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 2.25Cr-1Mo
72
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
7.00
RUPTURE EXPONENT, n
6.50
6.00
5.50
5.00
4.50
800
850
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.6-4: Rupture Exponent as a Function of Temperature: 2.25Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
73
The Welding Research Council, Inc.
13.7 3Cr-1Mo
The 3 Cr-1Mo alloy is not widely used and very little test data of any type, new or old, is available. It is
believed that there is a continuum of behavior from annealed 2 ¼ Cr-1Mo to the 5 Cr alloys. The sparse
stress rupture data was inadequate, on its own for analysis. Combining the available data with new data
for the 5 Cr alloy tubes showed the lower Cr alloy be slightly stronger as expected because of richer Mo
and lower Cr. MPC software permits identifying the behavior of the 3Cr-1Mo in the general population.
The average and minimum values represent that unique subset. No new tensile data were available.
The current API trend was adopted but indexed to the specified minimum properties. This resulted in
slightly lower curves when the curve was ratioed to those specified values.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.7-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 3Cr-1Mo
74
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.7-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 3Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
75
The Welding Research Council, Inc.
100
Cavg = 15.38106
Cmin= 15.785226
S
T
R
E
S
S 10
,
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.7-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 3Cr-1Mo
76
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
6.50
6.30
RUPTURE EXPONENT, n
6.10
5.90
5.70
5.50
5.30
5.10
4.90
4.70
4.50
800
850
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.7-4: Rupture Exponent as a Function of Temperature: 3Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
77
The Welding Research Council, Inc.
13.8 5Cr-0.5Mo
A large amount of data on 5Cr-0.5Mo tubes was obtained from overseas sources. The stress rupture
database exceeded 500 test results, many lasting many years. Tensile data were also obtained but there
was significant scatter, especially at higher temperatures. Over 20 heats were evaluated with good
agreement with the current lines.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.8-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 5Cr-0.5Mo
78
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.8-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 5Cr-0.5Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
79
The Welding Research Council, Inc.
100
Cavg = 15.58928
Cmin= 16.025829
S
T
R
E
S
S 10
,
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.8-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 5Cr-0.5Mo
80
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
6.50
6.30
RUPTURE EXPONENT, n
6.10
5.90
5.70
5.50
5.30
5.10
4.90
4.70
4.50
800
850
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.8-4: Rupture Exponent as a Function of Temperature: 5Cr-0.5Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
81
The Welding Research Council, Inc.
13.9 5Cr-0.5Mo-Si
There are no new data sources for 5Cr-0.5Mo-Si. Therefore, the material parameters developed for 5Cr0.5Mo are used to develop the following plots.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.9-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 5Cr-0.5Mo-Si
82
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.9-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 5Cr-0.5Mo-Si
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
83
The Welding Research Council, Inc.
100
Cavg = 15.58928
Cmin= 16.025829
S
T
R
E
S
S 10
,
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.9-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 5Cr-0.5Mo-Si
84
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
6.50
6.30
RUPTURE EXPONENT, n
6.10
5.90
5.70
5.50
5.30
5.10
4.90
4.70
4.50
800
850
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.9-4: Rupture Exponent as a Function of Temperature: 5Cr-0.5Mo-1Si
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
85
The Welding Research Council, Inc.
13.10 7Cr-0.5Mo
This alloy is seldom specified and has been deleted from several current ASTM specifications. Little data
could be found in the literature and the data were not considered statistically meaningful or suitable for
generating new curves. The plots shown are based on the previous API 530 curves for the alloy
converted to the format used in this document. They are not intended to represent any change in the
properties anticipated.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
TEMPERATURE, F
Figure 13.10-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 7Cr-0.5Mo
86
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.10-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter Miller – Comparison of Existing RP530 Data and Proposed New Data in US
Customary Units Based on the Average Larson-Miller Constant: 7Cr-0.5Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
87
The Welding Research Council, Inc.
100
Cavg = 19.62055
Cmin= 20.43746
S
T
R
E
S
S 10
,
K
s
i
1
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.10-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 7Cr-0.5Mo
88
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
8.00
7.80
RUPTURE EXPONENT, n
7.60
7.40
7.20
7.00
6.80
6.60
6.40
6.20
6.00
900
950
1000
1050
1100
1150
1200
TEMPERATURE, F
Figure 13.10-4: Rupture Exponent as a Function of Temperature: 7Cr-0.5Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
89
The Welding Research Council, Inc.
13.11 9Cr-1Mo
The data base compiled was confined to tubes produced overseas for heat exchangers as opposed to the
original database of domestic products that produced an unusually wide scatter band. The relatively
good oxidation resistance of the alloy permitted tests to very low stresses and a normal scatter band was
obtained from this analysis. Most of the data tracked API’s mean line but the resulting minimum (design)
lines are higher than the current lines at most temperatures. A second order polynomial was selected to
provide conservatism for extrapolation beyond the range of available data.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
1400
TEMPERATURE, F
Figure 13.11-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 9Cr-1Mo
90
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
42
44
46
48
50
52
54
LARSON‐MILLER PARAMETER/1000
Figure 13.11-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 9Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
91
The Welding Research Council, Inc.
100
Cavg = 25.85909
Cmin= 26.223587
S
T
R
E
S
S 10
,
K
s
i
1
42
44
46
48
50
52
54
LARSON‐MILLER PARAMETER/1000
Figure 13.11-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 9Cr-1Mo
92
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
11.00
10.00
RUPTURE EXPONENT, n
9.00
8.00
7.00
6.00
5.00
4.00
3.00
900
950
1000
1050
1100
1150
1200
1250
1300
TEMPERATURE, F
Figure 13.6-4: Rupture Exponent as a Function of Temperature: 9Cr-1Mo
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
93
The Welding Research Council, Inc.
13.12 9Cr-1Mo-0.25V
For this material new data were obtained primarily from Japan.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
200
400
600
800
1000
1200
1400
TEMPERATURE, F
Figure 13.12-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: 9Cr-1Mo-0.25V
94
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
52
54
56
58
60
62
LARSON‐MILLER PARAMETER/1000
Figure 13.12-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: 9Cr-1Mo-0.25V
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
95
The Welding Research Council, Inc.
100
Cavg = 30.36423
Cmin= 30.886006
S
T
R
E
S
S 10
,
K
s
i
1
52
54
56
58
60
62
LARSON‐MILLER PARAMETER/1000
Figure 13.12-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: 9Cr-1Mo-0.25V
96
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
15.00
RUPTURE EXPONENT, n
13.00
11.00
9.00
7.00
5.00
3.00
900
950
1000
1050
1100
1150
1200
1250
1300
TEMPERATURE, F
Figure 13.12-4: Rupture Exponent as a Function of Temperature: 9Cr-1Mo-0.25V
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
97
The Welding Research Council, Inc.
13.13 Type 304L Stainless Steel
Type 304L Stainless Steel – Very little rupture testing of 304L is intentionally carried out. MPC studied
many heats and found 304 produced with carbon content in the range of 0.04%. These were used as the
basis for estimating performance at the L grade level.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.13-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 304L Stainless Steel
98
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
32
34
36
38
40
42
LARSON‐MILLER PARAMETER/1000
Figure 13.13-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 304L Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
99
The Welding Research Council, Inc.
100
Cavg = 17.55
Cmin= 18.287902
S
T
R
E
S
S 10
,
K
s
i
1
32
34
36
38
40
42
LARSON‐MILLER PARAMETER/1000
Figure 13.13-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 304L Stainless Steel
100
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
9.50
9.00
RUPTURE EXPONENT, n
8.50
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.13-4: Rupture Exponent as a Function of Temperature: Type 304L Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
101
The Welding Research Council, Inc.
13.14 Type 304 & 304H Stainless Steel
Data was obtained from overseas sources. Only data on tubes were utilized since the data were
adequate for analysis. A total of 28 heats where studied of different manufacturing process and
producers. More than 450 results were included in the final data base. Materials could not be separated
and so 304 and 304H were lumped together. The resulting scatter band was less than the current curves
but the minimum was about the same.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.14-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 304 & Type 304H
Stainless Steel
102
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.14-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 304 & Type 304H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
103
The Welding Research Council, Inc.
100
Cavg = 15.52195
Cmin= 16.145903
S
T
R
E
S
S 10
,
K
s
i
1
30
32
34
36
38
40
42
44
46
LARSON‐MILLER PARAMETER/1000
Figure 13.14-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 304 & Type 304H Stainless Steel
104
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
7.00
RUPTURE EXPONENT, n
6.50
6.00
5.50
5.00
4.50
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.14-4: Rupture Exponent as a Function of Temperature: Type 304 & Type 304H Stainless
Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
105
The Welding Research Council, Inc.
13.15 Type 316L Stainless Steel
Data analysis was performed on Type 316L to develop the Type 317L parameters, see paragraph 12.16.
In addition, the data indicates that the differences in the yield and ultimate tensile strength trend curves
are indistinguishable. Therefore, the material parameters developed for Type 317L are used for Type
316L.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.15-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 316L Stainless Steel
106
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.15-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 316L Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
107
The Welding Research Council, Inc.
100
Cavg = 15.2
Cmin= 15.740107
S
T
R
E
S
S 10
,
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.15-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 316L Stainless Steel
108
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
9.50
RUPTURE EXPONENT, n
8.50
7.50
6.50
5.50
4.50
3.50
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.15-4: Rupture Exponent as a Function of Temperature: Type 316L Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
109
The Welding Research Council, Inc.
13.16 Type 316 & 316H Stainless Steel
Over 700 data points were included in the final set, mainly on tubular products. Other product forms were
included to obtain results at over 1500F (low stresses). The data were all from foreign sources. The
tensile trends were remarkably similar to the current trends, when the different room temperature index
values were considered. Some heats showed poor stress rupture behavior. These aspects are being
studied further. However, the design values are very similar to those used now where the curves are
supported by data.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.16-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 316 & Type 316H
Stainless Steel
110
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
30
32
34
36
38
40
42
LARSON‐MILLER PARAMETER/1000
Figure 13.16-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 316 & Type 316H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
111
The Welding Research Council, Inc.
100
Cavg = 16.30987
Cmin= 16.764145
S
T
R
E
S
S 10
,
K
s
i
1
30
32
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.16-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 316 & Type 316H Stainless Steel
112
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
6.50
6.30
RUPTURE EXPONENTENT, n
6.10
5.90
5.70
5.50
5.30
5.10
4.90
4.70
4.50
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.16-4: Rupture Exponent as a Function of Temperature: Type 316 & Type 316H Stainless
Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
113
The Welding Research Council, Inc.
13.17 Type 317L Stainless Steel
There are very little data available on Type 317L. Thus far only a few test results were found, some were
incomplete and relatively short. However, a database of modern low carbon Type 316 was compiled from
Japan. This is far larger than anything Smith had to work with. MPC heat centered procedures enable
indexing on the limited 317L data and adjusting to provide a better estimate of low carbon material
performance. These heats should have increased nitrogen levels.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.17-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 317L Stainless Steel
114
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.17-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant (Using Type 316L Data): Type 317L Stainless
Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
115
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.17-3: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant (Showing Type 317L Data Points Relative to
Type 316L Parameter Equations): Type 317L Stainless Steel
116
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 15.2
Cmin= 15.740107
S
T
R
E
S
S 10
,
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.17-4: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 317L Stainless Steel (Using Type 316L Data)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
117
The Welding Research Council, Inc.
9.50
RUPTURE EXPONENT, n
8.50
7.50
6.50
5.50
4.50
3.50
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.17-5: Rupture Exponent as a Function of Temperature: Type 317L Stainless Steel (Using
Type 316L Date)
118
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.18 Type 321 Stainless Steel
Only 321 tube data conforming to modern specifications, but not classified as 321H by the foreign
suppliers was used. The average stress rupture strength found is in reasonable agreement with Smith's
original analyses for MPC that provided the values used by API 530 for this material. However, the
variance was much smaller in the current work. It is believed that Smith included products that did not
conform to today's specifications. Therefore the minimum strength is a more reasonable (higher) fraction
of the average. Failure to assure proper heat treatment and composition can lead to unsatisfactory
performance.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.18-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 321 Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
119
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
24
26
28
30
32
34
LARSON‐MILLER PARAMETER/1000
Figure 13.18-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 321 Stainless Steel
120
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 13.325
Cmin= 12.8
S
T
R
E
S
S 10
,
K
s
i
1
24
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.18-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 321 Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
121
The Welding Research Council, Inc.
6.25
RUPTURE EXPONENT, n
5.75
5.25
4.75
4.25
3.75
3.25
2.75
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.18-4: Rupture Exponent as a Function of Temperature: Type 321 Stainless Steel
122
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.19 Type 321H Stainless Steel
The data collection focused on tubular products. The yield strength data found were scattered, as is often
the case for products heat treated to high temperatures, rapidly cooled and then straightened. Statistical
analysis of yield strengths revealed a weak temperature correlation, best described by a straight line.
The stress rupture data displayed less scatter than the API 530 plot for this alloy probably because of
greater attention to conformance of the materials to the H grade requirements. The average behavior
was substantially unchanged, but the minimum was elevated. Most data were obtained for material
produced by modern processes in Japan.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.19-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 321H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
123
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
LARSON‐MILLER PARAMETER/1000
Figure 13.19-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 321H Stainless Steel
124
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 14.75958
Cmin= 15.293986
S
T
R
E
S
S 10
,
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.19-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 321H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
125
The Welding Research Council, Inc.
6.50
RUPTURE EXPONENT, n
6.00
5.50
5.00
4.50
4.00
3.50
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.19-4: Rupture Exponent as a Function of Temperature: Type 321H Stainless Steel
126
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.20 Type 347 Stainless Steel
For this material new data were obtained primarily from Japan. The trends are demonstrated by the
equations and coefficients found in Annex F of API 579-1/ASME FFS-1.
100
S
T
R
E
S
S 10
,
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
1250
1500
TEMPERATURE, F
Figure 13.20-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 347 Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
127
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
26
28
30
32
34
36
38
LARSON‐MILLER PARAMETER/1000
Figure 13.20-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 347 Stainless Steel
128
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 14.25
Cmin= 14.889042
S
T
R
E
S
S 10
,
K
s
i
1
26
28
30
32
34
36
38
LARSON‐MILLER PARAMETER/1000
Figure 13.20-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 347 Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
129
The Welding Research Council, Inc.
11.00
10.00
RUPTURE EXPONENT, n
9.00
8.00
7.00
6.00
5.00
4.00
3.00
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.20-4: Rupture Exponent as a Function of Temperature: Type 347 Stainless Steel
130
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.21 Type 347H Stainless Steel
For this material new data were obtained primarily from Japan. The trends are demonstrated by the
equations and coefficients found in Annex F of API 579-1/ASME FFS-1.
100
S
T
R
E
S
S
,
10
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
K
s
i
EXISTING RP 530 TENSILE
EXISTING RP 530 YIELD
1
0
250
500
750
1000
TEMPERATURE, F
1250
1500
Figure 13.21-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: Type 347H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
131
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.21-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: Type 347H Stainless Steel
132
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 13.79341
Cmin= 14.458025
S
T
R
E
S
S 10
,
K
s
i
1
26
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.21-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: Type 347H Stainless Steel
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
133
The Welding Research Council, Inc.
9.50
9.00
8.50
RUPTURE EXPONENT, n
8.00
7.50
7.00
6.50
6.00
5.50
5.00
4.50
4.00
3.50
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.21-4: Rupture Exponent as a Function of Temperature: Type 347H Stainless Steel
134
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.22 Alloy 800
The data chosen for this class of material excluded results from heats that do not take advantage of the
heat treating and compositional controls imposed to obtain the 800H and 800HT grades. These include
controls on aluminum, titanium, and carbon contents, grain size and annealing temperatures. Such
unrestricted material is not usually used for creep service and the data base is relatively small. The very
high temperatures permitted for 800H and 800HT cannot be recommended with confidence.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
1750
TEMPERATURE, F
Figure 13.22-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08800 (Alloy 800)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
135
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
EXISTING RP 530 AVERAGE
S
T
R
E
S
S 10
,
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
LARSON‐MILLER PARAMETER/1000
Figure 13.22-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: UNS N08800 (Alloy 800)
136
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 16.50878
Cmin= 17.005384
S
T
R
E
S
S 10
,
K
s
i
1
28
30
32
34
36
38
40
42
44
LARSON‐MILLER PARAMETER/1000
Figure 13.22-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: UNS N08800 (Alloy 800)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
137
The Welding Research Council, Inc.
6.00
5.80
RUPTURE EXPONENT, n
5.60
5.40
5.20
5.00
4.80
4.60
4.40
4.20
4.00
900
950
1000
1050
1100
1150
1200
1250
1300
1350
1400
1450
1500
TEMPERATURE, F
Figure 13.22-4: Rupture Exponent as a Function of Temperature: UNS N08800 (Alloy 800)
138
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.23 Alloy 800H
Yield and ultimate tensile strength data were obtained for tubular products of Alloy 800H. The stress
rupture data shown represent a broad international database generally in conformance with prior
estimates. Some of the test results captured here are from tests lasting in excess of 100,000 hours.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
1750
TEMPERATURE, F
Figure 13.23-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08810 (Alloy 800H)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
139
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
30
32
34
36
38
40
42
44
46
LARSON‐MILLER PARAMETER/1000
Figure 13.23-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: UNS N08810 (Alloy 800H)
140
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 16.04227
Cmin= 16.564046
S
T
R
E
S
S 10
,
K
s
i
1
30
32
34
36
38
40
42
44
46
LARSON‐MILLER PARAMETER/1000
Figure 13.23-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: UNS N08810 (Alloy 800H)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
141
The Welding Research Council, Inc.
7.00
RUPTURE EXPONENT, n
6.50
6.00
5.50
5.00
4.50
1100
1150
1200
1250
1300
1350
1400
1450
1500
1550
1600
1650
TEMPERATURE, F
Figure 13.23-4: Rupture Exponent as a Function of Temperature: UNS N08810 (Alloy 800H)
142
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.24 Alloy 800HT
MPC combined the original database used in setting the control limits that defined the 800HT class of
material with more recent data on tubular products from overseas sources. Some results on the newer
products were for tests that lasted beyond 30,000 hours at low stresses and very high temperatures. As
a result the parameter curve is well defined. It should be noted that the improvement for 800HT versus
800H is not expected to be very large at intermediate temperatures and disappears at very high
temperatures due to the redissolving of carbides and strengthening nickel-aluminum-titanium compounds.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
1750
TEMPERATURE, F
Figure 13.24-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08811 (Alloy 800HT)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
143
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.24-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: UNS N08811 (Alloy 800HT)
144
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 13.2341
Cmin= 13.606722
S
T
R
E
S
S 10
,
K
s
i
1
28
30
32
34
36
38
40
LARSON‐MILLER PARAMETER/1000
Figure 13.24-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: UNS N08811 (Alloy 800HT)
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
145
The Welding Research Council, Inc.
7.25
RUPTURE EXPONENT, n
6.75
6.25
5.75
5.25
4.75
4.25
3.75
900
995
1090
1185
1280
1375
1470
1565
1660
1755
1850
TEMPERATURE, F
Figure 13.24-4: Rupture Exponent as a Function of Temperature: UNS N08811 (Alloy 800HT)
146
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
13.25 HK-40
Elevated temperature yield and ultimate tensile strength values were obtained for the high carbon content
HK 40 castings. The strength properties found varied, but the trend shown was strongly indicative of an
increase in yield strength in the 1200-1300˚F range due to precipitation at those temperatures. The
extent of the increase in yield strength is not easily displayed by the smooth curve of the polynomial used
to display the properties. The large database collected shows lower minimums than the existing API 530
curves.
100
S
T
R
E
S
S 10
,
K
s
i
PROPOSED TENSILE
STRENGTH
PROPOSED YIELD STRENGTH
1
0
250
500
750
1000
1250
1500
1750
TEMPERATURE, F
Figure 13.25-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of
Existing RP530 Data and Proposed New Data in US Customary Units: HK-40
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
147
The Welding Research Council, Inc.
100
PROPOSED AVERAGE
PROPOSED MINIMUM
S
T
R
E
S
S 10
,
EXISTING RP 530 AVERAGE
EXISTING RP 530 MINIMUM
RUPTURE DATA
K
s
i
1
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.25-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary
Units Based on the Average Larson-Miller Constant: HK-40
148
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
The Welding Research Council, Inc.
100
Cavg = 10.4899
Cmin= 10.856489
S
T
R 10
E
S
S
,
K
s
i
1
0.1
22
24
26
28
30
32
34
36
LARSON‐MILLER PARAMETER/1000
Figure 13.25-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US
Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average
Time-Dependent Properties: HK-40
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
149
The Welding Research Council, Inc.
5.00
4.80
RUPTURE EXPONENT, n
4.60
4.40
4.20
4.00
3.80
3.60
3.40
3.20
3.00
1400
1450
1500
1550
1600
1650
1700
1750
1800
TEMPERATURE, F
Figure 13.25-4: Rupture Exponent as a Function of Temperature: HK-40
150
WRC Bulletin 541
Evaluation of Material Strength Data for Use in Conjunction with API 530
1850