Materials
ASME Section VIII
Materials Section VIII
General Requirements
User Responsibilities
 The user or his designated agent must
establish the design requirements for the
vessel
 Design requirements may include selection of
materials.
 It is recommended that the User assure
himself that the materials selected for the
vessel are suitable for its intended purpose.
Materials Section VIII
Manufacturers Requirements

The manufacturers must select materials based on Code
requirements and the design parameters the User has
specified.

In addition to safety requirements, the manufacturer should
consider the suitability of a material for a specific application.

Choice of the specific material is up to the Manufacturer, so
long as Code and design requirements are met
Materials Section VIII
Authorized Inspector Requirements
 The materials must be checked to verify that
they are within the tolerances specified in the
material specification.
 The Material Test Report must be compared to
material and markings to ensure proper
identification.
 The AI must verify that material imperfections
repaired by welding were properly repaired.
 All materials must be inspected for proper
identification.
Materials Section VIII
Material Selection and Suitability
1.
Material selection should be based on the suitability of the
material taking in to account the following considerations:
Retention of satisfactory mechanical properties.
Resistance to corrosion, erosion, and Oxidation.
2.
Even though the material may meet Code requirements, it
may not be suitable for the particular application.
3.
Even if a material is not suitable for a particular application, if
all design, inspection and test requirements are met, the
vessel meets the Code.
The Code is concerned with the safety, not operability
4.
The Code is not intended to replace design competency
Materials Section VIII
REQUIREMENTS GOVERNING PERMITTED MATERIALS
Section VIII, Division I requirements regarding
materials are found in the following areas:

Subsection A provides general requirements which
apply to all materials in all cases.

Subsection B provides special material requirements
based on method of fabrication and type of services.

Subsection C provides supplemental requirements
for particular types or classes of materials.
Materials Section VIII

Mandatory Appendices discuss special application
requirements.

Code cases may apply as permitted by contract or
Jurisdictional Authority.

Since Subsection C addresses specific materials, its
requirements take precedence over Subsection A
requirements.
Materials Section VIII


The use of Section II material is acceptable if the
material is permitted by Subsection C.
Requirements regarding types of materials
permitted fall into the following five categories.
•
General Requirements
UG-4
•
Material Requirements
UG-4/8
•
Parts Requirements
UG-11
•
Welding Material Requirements
UG - 9
•
Req. for Unidentified Material UG-10
Materials Section VIII
General Requirements UG-4
Material Subject to stress must conform to the specifications of
Section II and must be acceptable under Subsection VIII as listed
on the stress tables or as permitted by a code case.
 Exceptions are listed in UG-9 (see Requirements for
Welding Materials), UG-10 (see Requirements for
Unidentified Materials), UG-11 (see Requirements for
Parts) and UG –15.
 UG-15 provides for use of an item when the specific
product form is not referenced by Subsection C but is listed
in Section II as another product form of a specification
listed in Subsection C.
Material for nonpressure parts need not conform to the above
requirements, but must be of weld able quality in conformance
with UW-5 (a).
Materials Section VIII
Defined weldable quality:
In design, the allowable stress values for non pressure part
material not identified in accordance with UG-93 cannot
exceed 80 % of the stress value allowed for similar material
in Subsection C.
Material not listed on the stress tables of Section II part D
for Section VIII may not be used unless it has been
submitted to and approved by the Boiler and Pressure
Vessel Committee in accordance with Appendix B.
Materials Section VIII
Information required by the Boiler and Pressure Vessel
Committee includes the following:





Mechanical Properties
Weldability
Physical properties when formed or treated
Patents
Code Cases
Materials Section VIII
Material Outside the limits of the specifications of
Section II in terms of Size and/or thickness may
be used provided:



It complies with other specifications, and
No size or thickness limitations are listed in the
stress tables.
If the chemical or mechanical properties of the
material vary with thickness or size, the material
must be shown to conform to the requirements
listed for the closest thickness or size.
Materials Section VIII
Requirements for Material
The rule of thumb is that is no welding is involved, the
item is considered a material.
Welded pipes and tubes without filler material are also
considered material. Commonly referred to as ERW
“Electric Resistance Welded”.
Materials Section VIII
In determining permissible material, pay
special attention to :

Use of the proper stress value at the correct
temperature

Use of the footnotes for each stress table

The requirements of each Subsection
Materials Section VIII
General requirements for materials are found in specific sections. Note
in the special requirements listed below.







Plate (UG-5)
Forgings (UG-6)
Castings (UG-7)
Allowable stress values given in Subsection C for
castings must be multiplied by a casting quality
factor per UG-24.
Cast iron is an exception to this
requirement.
Pipes and Tubes (UG-8)
UG-8 also covers special requirements for finned tubes.
Bolts and Studs (UG-12)
Nuts and Washers (UG-13)
Rods and Bars (UG-14)
Materials Section VIII
Specific requirements for each class of material are listed in Subsection C.
Generally, these requirements are found in
UXX-5 through 15.
For example, specific requirements for
various forms of carbon steel are found in the
following paragraphs.
 Plates (UCS-6)
 Forgings (UCS-7)
 Castings (UCS-8)
 Pipes and Tubes (UCS-9)
 Bolts (UCS-10)
 Nuts and Washers (UCS-11)
 Bars and Shapes (UCS-12)
Materials Section VIII
Note the following requirements for various classes of material.

UCS-5 requires that no welding or oxygen cutting be performed
on material with a carbon content over 0.35%.

UCS-6 provides for the use of SA-36 and SA-283 Grades A, B, C
and D material for pressure parts providing the following
conditions are met:




Vessel is not for lethal services
Vessel is not an unfired steam boiler
Design temperature must be between -20ºF and 650ºF
Plate thickness may not exceed 5/8“ if strength welding is used
Materials Section VIII

ULT lists special restrictions for low
temperature applications.

UHT-82 lists special restrictions for
vessels which have had their tensile
strength enhanced by heat treatment.
Materials Section VIII
Requirements for Parts

Code parts are defined in UG-120(c)

Distinctions between parts and material are also discussed in
UG-8 footnote 3, UG-90 (b)(4), and UG-11 (i).

The distinctions between parts and material effects the
degree of documentation which must accompany the item.

Except as permitted in UG-11 (a)(b) and (c), pressure
vessel parts requiring inspection under Section VIII must
be accompanied by a Partial Data Report completed by a
Certificate Holder and certified by an Authorized
Inspector.
Materials Section VIII
Miscellaneous Pressure Parts
UG-11 covers requirements for use of miscellaneous pressure parts
such as fittings, couplings, flanges, weld necks and caps.
 UG-11 (a) covers cast, forged, rolled, or die formed standard
pressure parts.
 UG-11 (b) covers cast, forged, rolled, or die formed non standard
pressure parts.
 UG-11 (c) covers welded standard pressure parts for use other
than in the shell or heads of a vessel.
Materials Section VIII
These parts are covered separately from
plate, pipe, tubes, forgings and bar stock
because they are covered by ANSI
standards.

ASTM specifications cover basic
requirements for dimensional tolerances for
plate and pipe, whereas ANSI standards
include dimensional tolerances for more
complex fittings.
Materials Section VIII
Requirement for Welding Material :
Welding material to be used in Code Vessels must
comply with the following:



Section VIII requirements
Section IX requirements
Applicable welding procedure specifications
Materials Section VIII
Code requirements regarding selection of welding materials
are not stringent. Particular care should be exercised in
selecting the proper welding material.
 Section VIII and IX requirements address selection of
welding materials only on the basis of materials
properties.
 Even if the welding material meets requirements for
tensile strength, ductility and impact, service problems
may still occur.
 As with other materials, the service application should
be considered.
Materials Section VIII
Requirements for Unidentified Material UG-10

UG-10 provides for the use of material not fully identified
and for the use of material identified with or produced to
a specification not permitted by the Code.

Under UG-10 (a), material may be recertified to an
acceptable specification by another organization or by
the Manufacturer if heat or lot traceability and chemical
composition are available from the original material
manufacturer.
Comparison of this information allows the
manufacturer to
established that the material
specification is identical to an SA specification.
Materials Section VIII

Under UG-10 (b), if the chemical composition not
available from the original manufacturer, the vessel
Manufacturer may perform all requirements and
treatments specified in the SA specification.
If the results are acceptable, the manufacturer
may
recertify the material as meeting the SA
specification.

Under UG-10 (c), if the chemical composition not
available, the Manufacturer may perform all the
required tests and treatments required by the Code to
recertify the material to an SA specification.
SECTION II MATERIAL SPECIFICATIONS
Section II provides specifications for various applications of material,
parts, and welding materials.
For each application, several different specifications may apply.
Basic Material Specification
Basic Material Specifications typically contain the following information:
•
Scope
•
•
•
•
•
Applicable documents – references to other specifications
General requirements and basis of purchase
Chemical requirements
Mechanical requirements
Supplementary requirements
SECTION II MATERIAL SPECIFICATIONS
General Delivery Specification
General Delivery Specifications contain specific
information regarding various product forms.
They are as follows :





Pipe (SA-530)
Tube (SA-450)
Stainless Steel (SA-480)
Carbon and Low Alloy Steel Plate (SA-20)
Structural Plate and Shapes (SA-6)
SECTION II MATERIAL SPECIFICATIONS
Specifications Regarding Other Requirements
Other specifications covering areas such as
testing may be referenced by basic material
specifications or general delivery specifications.
SECTION II MATERIAL SPECIFICATIONS
REQUIREMENTS FOR MATERIAL TESTING AND
EXAMINATION
Material testing and examination is covered in basic material
specifications in Section II.
Under UG-15, material testing and examination may be
required for product forms not covered by the stress tables.
Results of material tests must only be reported in th Material
Test Report for Plates.
SECTION II MATERIAL SPECIFICATIONS
Types of Material Tests Required by Section II
1.
2.
Chemical analysis of all material
Mechanical Properties of all material
 Tensile, yield and elongation testing of all products
except some carbon steel tubes
 Hardness testing of forgings, tubes and bars
 Bend tests of bars and tubular products
 Flattening, flanges, flare and crush testing of tubular
products
 Guided bend tests of weld filler metal and welded
products
 Charpy Impact testing of mild steel and low alloy weld
filler metal
SECTION II MATERIAL SPECIFICATIONS
3.
4.
5.
6.
Hydrostatic testing of tubular products
Ultrasonic testing of quenched and tempered forgings
Eddy Current testing of tubular products and castings
Magnetic particle testing of quenched and tempered forgings
and some castings
SECTION II MATERIAL SPECIFICATIONS
Charpy Impact Testing UG-84
Charpy Impact Tests must be performed on all weldments
and all materials for shells, heads, nozzles, and other
vessel parts subject to stress unless exempted by
Subsection C.


Regardless of the material specification, impact
testing is required for any welded component
exceeding 4" in thickness.
Components exceeding 6" in thickness attached by
bolting must be impact tested if the minimum design
temperature is less than 120ºF.
SECTION II MATERIAL SPECIFICATIONS
Test Procedures
The test procedures and apparatus must conform to SA-370.
Except as listed in Table UG-84.4, impact test temperature must
not be higher than the minimum design metal temperature.
Test specimens must conform to Figure UG-84.

Reduction of test specimens may be permissible under UG84(c)(2)(a).
Rejection UG-84-(j)
If the vessel test plate fails the impact test, the welds represented by
the plate are unacceptable.

Reheat treatment and retesting are permitted.
SECTION II MATERIAL SPECIFICATIONS
Impact Test Exemptions
As a general rule, assume that all carbon and low alloy
steels must be impact tested, then check to see if there is
an exemption.
UG-20(f) exempts P-1 Grade 1 or 2 when:


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
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Nominal thickness is less than 1/2" for curve “A” materials.
Nominal thickness is less than or equal to 1 inch. For material
on curve B, C, or D of Figure UCS-66.
The completed vessel is tested per UG-99(b).
The design temperature is between -20ºF and 650ºF.
Thermal or mechanical shock loadings do not effect design.
Cyclical loading does not effect design
SECTION II MATERIAL SPECIFICATIONS




UCS-66(a) exempts material if the minimum design metal
temperature and thickness combination falls above the applicable
curve on Figure UCS-66.
UCS-66(b) permits reduction of the Figure UCS-66(a) minimum
design temperature if the thickness of the vessel exceeds the
thickness required.
UCS-66(c) exempts ANSI B16.5 ferritic steel flanges used at
design temperature greater than or equal to -20ºF.
UCS-66(d) exempts nuts and materials less than .098 " thick
when they are used at design metal temperatures greater than or
equal to -50 ºF.
SECTION II MATERIAL SPECIFICATIONS

UCS-68(c) allows a 30ºF reduction in an
impact testing exemption temperature greater
than or equal to -50 ºF if post weld heat
treatment is performed when it nit a Code
requirement.
 UNF-65 lists exemptions for nonferrous
materials such as wrought alumunium alloys,
copper and copper alloys, nickel and nickel
alloys, cast alumunium, titanium and
zirconium.
 UHA-51 lists exemptions for high alloy steel
materials.
SECTION II MATERIAL SPECIFICATIONS
Material Test Reports
The material manufacturer must report the results of all
tests performed on a material as required by:



The material specification
Other supplementary requirements, and
The Certificate Holder’s purchase order.
Material Test Reports must come from the material
manufacturer.
SECTION II MATERIAL SPECIFICATIONS
The Material Test Report gives information
regarding the following.
 Information on the material specification
Tests
 Examinations
 Repairs
 Heat Treatments

Supplementary and special requirements
 Identification of material
 Heat number if applicable

SECTION II MATERIAL SPECIFICATIONS
A Material Test Report must be provided:
1. For plate materials as provided in the
material specification
2. When material specification requirements
are completed by other than the material
manufacturer (except UG-4, UG-10, UG-11,
UG-15)
3. When requirements or provisions of
Selection VIII exceed or supplement the
requirements of the material specification.
SECTION II MATERIAL SPECIFICATIONS
Welding materials need not have a Material Test Report
or Certificate of Compliance provided:
1.
2.
The container is marked in accordance with Section II, Part
C, or
The container is marked and traceable to materials used in
the WPS
SECTION II MATERIAL SPECIFICATIONS
Certificates of Compliance
A certificate of compliance is a written statement from a
material manufacturer or supplier certifying that the
material supplied is in compliance with a material
specification.
Certificates of compliance may or may not be acceptable
for various materials.