High Temperature Alloys for Power
Plant Applications
ARIPPA Meeting
April 26th, 2005
Jason Wilson
Rolled Alloys
Nominal Chemistries
Alloy
UNS
Ni
304 SS
S30400 9
Cr
Fe Si
18.3 70 70
RA253MA S30908 11
21
65 1.7
309 SS
S30815 13
23
62 0.8
310 SS
S31008 20
25
52 0.5
RA330®
N08330 35
19
43 1.25
RA353MA S35315 35
25
36 1.2
Alloy 601
22.5 14 0.2
N06601 61.5
Other
Ce, N
Ce, N
Al
High Temperature Concerns

Distortion


Creep Deformation
Thermal Expansion

Corrosion

Oxidation




Temperature
Limitations
Erosion
Sulfidation
Molten Salts
Stress

Do not subject alloys
to undue stress



Uneven Heating
Thermal Expansion
Thermal Shock
Uneven Heating

HOT
Uneven Thermal
Expansion



COOL
Typical Causes



RA 253 MA Burner Can
Buckling/Warping
Cracking
Flame Impingement
Large variation in
cross section
Sharp temperature
gradients
Thermal Expansion


At 1800F, a 20 foot
RA330 pipe expands
over 4 inches
Keys

Major


Allow for expansion in
the design
Minor


Higher strength alloy
Lower coefficient of
thermal expansion

Railroad on a hot day
Alloy 600 (3.75 in)
Coefficient of Thermal Expansion
(in/in°F x 10-6)
Alloy
1600oF
% Nickel
304 SS
8
11.0
309 SS
13
10.1
RA253MA
11
10.6
310 SS
20
10.15
800HT
32
10.2
RA330
35
9.8
RA353MA
35
9.86
Alloy 601
61
9.5
Strength


Ensure adequate
alloy strength at
temperature
Review CreepRupture data

Short Term Data is not
representative of how
the alloy will act in long
term service.
Strength

Raising Creep Strength

Carbon

Use H grades


Nitrogen



Min 0.4% Carbon & Coarse Grains
RA 253 MA and RA 353 MA
Nickel
Others

Co, Mo, W
Strength





Creep Demonstration
RA 253 MA, 601, 310,
321
0.040” thick rings
Temperature: 1832F
Time: 35 hours
Strength


Creep occurs above
roughly 1000oF
Permanent
Deformation or Flow


Time Dependent
Lower Stress than Y.S.
10,000 Hr Average Stress to Rupture
Alloy
UNS
Number
1600oF
1800oF
304 SS
S30400
1,400
309 SS
S30908
1,600
560
RA253MA
S30815
2,500
1,150
310 SS
S31008
1,500
660
800HT
N08811
3,500
RA330
N08330
RA353MA
Alloy 601
1900oF
2000oF
860
680
1,300
890
480
1,700
630
400
280
S35315
2,600
1,300
930
680
N06601
2,600
1,200
620
Strength

Incinerator bed


1920oF (Average)
Replaced RA330


6 months life
RA 353 MA lasting 8-9
months
Strength
Horizontal Radiant U-tubes.
6 inch OD and 11ga wall.
Condition after 10 months.
Batch Annealing at 1800°F.
Exothermic Atmosphere.
Operation 5 days/week 3 shifts
253MA Circulating Fluidized Bed
- 8-1/2 foot diameter x 23 foot long dip tubes.
- Two per boiler, eight boilers on site
- 1600-1650°F Temperatures
- Fuel – 70% Illinois Coal, 30% Powder River Basin, Tire Chips
- Dip tubes installed in 1999, Others in since 1998,
- 310 Stainless lasted 2 years prior to removal due to distortion
Strength
- RA253MA pans for the production of foam glass insulation
- Previous alloy used type 309 stainless
- Process temperature 1600°F
Strength
RA 353 MA pack coating retort.
36 in. diameter
48 in. high
3/8 inch thick
1675-2000°F – Argon on inside
Photo after 24 months in service
RA330 typically distorted 8 months
Tube Supports

Fired Boilers


RA353MA heavy plate
used as a header
support.
Replaced RA330
High Temperature Corrosion
Temperature Limitations


All alloys have their
limits.
Limiting Factors

Oxidation


310SS at 2100F
Not melting point
Strength
Oxidation

Spallation of the
protective oxide scale



Thinning
Internal oxide
penetration
Enhancers




Chromium
Silicon
Aluminum
Cerium
Type 310 stainless thermocouple tube
oxidized from operation at 2100 deg F
Suggested Temperature Limits (Air)
2400
2200
2000
1800
1600
1400
1200
1000
Oxidation Resistance
Cyclical Testing 1600 Hrs
Weight Gain, mg/cm2
100
80
60
40
20
0
1600F
304
309
1800F
RA 253 MA
2000F
310
RA330
2100F
RA353MA
Weight Gain, mg/cm2
Oxidation Resistance
Cyclic Testing 3000 Hrs
160
140
120
100
80
60
40
20
0
2000F
RA 353 MA
2100F
RA330
RA601
2150F - 1500 Hrs
800HT
Tube Spacers
RA353MA hand cuff bars on a packaged boiler
firing with natural gas.
Cyclones
Western U.S. Coke Plant
RA353MA shown after 1 year service
during inspection. 2000°F typical
Sulfidation

Attack by sulfur
compounds




SO2, H2S
At 1200°F and above
Molten Ni-Ni-S eutectic
Higher nickel alloys
most susceptible
Sulfidation of cast heat resistant alloy
used for a tire drop chute (Cement)
Sulfur/Chlorine Attack
1470-1650oF
Slab Reheat Furnace
Recuperator
11 Months Exposure
RA353MA replaced 309
with high silicon
Increased life from 7
months to over 24
months
19Cr-11Ni-2Si
Sulfidation
Chloride Attack

Chloride Attack



Thick Porous Scale
Rapid Thinning
Intergranular Attack
310 stainless tubeshield from refuse
fired boiler.
Tube Supports – Escatron (Spain)


Replaced RA253MA
Pressurized Fluid Bed
Boiler


6.8% Sulfur Lignite
Earlier Units <3.6% Sulfur



TIDD, Vartan
RA253MA successful
Coupon Testing




11 months
1475-1650°F
RA353MA – 0.1 mm
RA253MA – 1.1 mm
Flap Gates



Cement Kilns
Feeding of Scrap
Tires
RA353MA in use in 3
cement plants to date
in North & South
America
Erosion @ 1292oF (700oC)
Wastage Rate (mm/1000hr)
Particle Velocity of 1.2 m/s
3.5
3
2.5
2
1.5
1
0.5
0
RA353MA
304
625
Fe9Cr1Mo
Coal Tips




253MA used extensively
for coal nozzles
309 or 310 SS commonly
used for the air nozzles
353MA used at some
plants for upper
elevations of the boiler
353MA used at a
Midwestern utility


Specified since 2000
Replaced 253MA
Tube Shields




RA353MA used in
supercritical boilers
Specified at one US
Utility for hottest area
of superheater
Replaced type 309
stainless
Service life of 6 years
Tube Shields – Paper Mill

Fuel




Propane – Start up
Waste Oils
Hog Fuel
Bunker C

S35315 used since 1998

1 year life expectancy
Tube Shields







S35315 used in CFB
boiler
Protect primary
superheater tubes
1616 deg F
High S, High Cl coal
Extensive Soot Blowing
due to fouling
Replaced 309 SS
Still in service after 28
months.
Erosion


63 inch diameter
353MA cyclone
Temperatures




1750 to 2192°F
Refuse fired
Initial unit in service
for 1 year
Redesigned cyclone
made of 353MA
Erosion
Pressurized Fluidized
Bed Combustor Cyclone
AEP TIDD Project
Erosion
RA253MA Witch’s Hat
Fluid Bed Boiler System
Municipal Utility - Wisconsin

Foster Wheeler CFB

Fuel


Replaced RA253MA





Petcoke/Paper Pellets
Transfer Line
Fuel feed chute
Ash Drains
Installed Early 2004
Selected for

Abrasion/Distortion
Areas
Relative Costs
Alloy
Relative Cost Alloy
Relative Cost
RA309
1.00
RA 353 MA
2.70
RA 253 MA
1.30
RA601
3.60
RA310
1.35
RA 330
2.20
Ratios based on plate pricing during Spring 2005
Summary

Distortion



Allow for Thermal
Expansion
Minimize uneven
heating
Investigate Higher
Strength Alloys



H grades
MA grades
Nickel alloys

Corrosion

Oxidation/Erosion



Sulfidation


High Chromium
Ce, Si, Al Additions
Lower Nickel
Chlorides


Higher Nickel
Moderate Chromium