Designation: A 234/A 234M – 05a Used in USDOE-NE Standards
Standard Specification for
Piping Fittings of Wrought Carbon Steel and Alloy Steel for
Moderate and High Temperature Service1
This standard is issued under the fixed designation A 234/A 234M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope*
1.1 This specification2 covers wrought carbon steel and
alloy steel fittings of seamless and welded construction covered
by the latest revision of ASME B16.9, B16.11, MSS SP-79,
and MSS SP-95. These fittings are for use in pressure piping
and in pressure vessel fabrication for service at moderate and
elevated temperatures. Fittings differing from these ASME and
MSS standards shall be furnished in accordance with Supple-
mentary Requirement S58 of Specification A 960/A 960M.
1.2 Optional supplementary requirements are provided for
fittings where a greater degree of examination is desired. When
desired, one or more of these supplementary requirements may
be specified in the order.
1.3 This specification does not cover cast welding fittings or
fittings machined from castings. Cast steel welding fittings are
governed by Specifications A 216/A 216M and A 217/
A 217M.
1.4 This specification is expressed in both inch-pound units
and in SI units. However, unless the order specifies the
applicable “M” specification designation (SI units), the mate-
rial shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or SI units
are to be regarded separately as standard. Within the text, the
SI units are shown in brackets. The values stated in each
system are not exact equivalents; therefore, each system must
be used independently of the other. Combining values from the
two systems may result in nonconformance with the specifi-
cation.
2. Referenced Documents
2.1 In addition to those reference documents listed in
Specification A 960/A 960M, the following list of standards
apply to this specification.
2.2 ASTM Standards: 3
A 216/A 216M Specification for Steel Castings, Carbon,
Suitable for Fusion Welding, for High-Temperature Ser-
vice
A 217/A 217M Specification for Steel Castings, Martensi-
tic Stainless and Alloy, for Pressure-Containing Parts
Suitable for High-Temperature Service
A 960/A 960M Specification for Common Requirements
for Wrought Steel Piping Fittings
2.3 ASME Standards:4
B16.9 Steel Butt-Welding Fittings
B16.11 Forged Steel Fittings, Socket Welding and Threaded
2.4 ASME Boiler and Pressure Vessel Code:4
Section V Nondestructive Examination
Section VIII, Division 1, Pressure Vessels
Section IX Welding Qualifications
2.5 MSS Standards:5
MSS SP-25 Standard Marking System for Valves, Fittings,
Flanges, and Unions
MSS SP-79 Socket Welding Reducer Inserts
MSS SP-95 Swage(d) Nipples and Bull Plugs
2.6 ASNT Standard:
SNT-TC-1A(1984) Recommended Practice for Nondestruc-
tive Testing Personnel Qualification and Certification6
3. Ordering Information
3.1 See Specification A 960/A 960M.
4. General Requirements
4.1 Product furnished to this specification shall conform to
the requirements of Specification A 960/A 960M, including
any supplementary requirements that are indicated in the
1 This specification is under the jurisdiction of ASTM Committee A01 on Steel,
Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee
A01.22 on Steel Forgings and Wrought Fittings for Piping Applications and Bolting
Materials for Piping and Special Purpose Applications.
Current edition approved June 1, 2005. Published June 2005. Originally
approved in 1940. Last previous edition approved in 2005 as A 234/A 234M – 05.
2 For ASME Boiler and Pressure Vessel Code applications see related Specifi-
cation SA-234 in Section II of that Code.
3 For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
4 Available from ASME International, Three Park Avenue, New York, NY
10016–5990.
5 Available from Manufacturers Standardization Society of the Valve and Fittings
Industry, 1815 N. Fort Myer Drive, Arlington, VA 22209.
6 Available from American Society for Nondestructive Testing, 4153 Arlingate
Plaza, Columbus, OH 43228-0518.
1
*A Summary of Changes section appears at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
purchase order. Failure to comply with the requirements of
Specification A 960/A 960M constitutes non-conformance
with this specification. In case of a conflict between the
requirements of this specification and Specification A 960/
A 960M, this specification shall prevail.
5. Materials
5.1 The material for fittings shall consist of killed steel,
forgings, bars, plates, seamless or fusion-welded tubular prod-
ucts with filler metal added and shall conform to the chemical
requirements of Table 1. Unless otherwise specified for carbon
steel plates, the steel may be made to either coarse grain or fine
grain practice. Grade WP9 shall be made to fine grain practice.
5.2 A starting material specification that specifically re-
quires the addition of any element beyond those listed for the
materials in Table 1 for the applicable grade of material is not
permitted. This does not preclude the use of deoxidizers or the
judicious use of elements for grain size control.
6. Manufacture
6.1 Forging or shaping operations may be performed by
hammering, pressing, piercing, extruding, upsetting, rolling,
bending, fusion welding, machining, or by a combination of
two or more of these operations. The forming procedure shall
be so applied that it will not produce injurious imperfections in
the fittings.
NOTE 1—Fittings NPS-4 and under may be machined from hot-forged
or rolled, cold-sized, and straightened bar stock having the chemical
composition of the Grade in Table 1 and the mechanical properties of the
Grade in Table 2. Heat treatment shall be in accordance with Section 7. All
caps machined from bar stock shall be examined by liquid penetrant or
magnetic particle in accordance with S52 or S53 in Specification
A 960/A 960M.
6.2 All welds including welds in tubular products from
which fittings are made shall be (1) made by welders, welding
operators, and welding procedures qualified under the provi-
sions of ASME Section IX, (2) heat treated in accordance with
Section 7 of this specification, and (3) radiographically exam-
ined throughout the entire length of each weld in accordance
with Article 2, ASME Section V with acceptance limits in
accordance with Paragraph UW-51 of ASME Section VIII,
Division 1 of the ASME Boiler & Pressure Vessel Code. In
place of radiographic examination, welds may be ultrasonically
examined in accordance with Appendix 12 of Section VIII. The
NDE of welds in Grades WPB, WPC, WP1, WP11 Class 1,
WP11 Class 2, WP11 Class 3, WP12 Class 1, WP12 Class 2,
and WPR may be performed either prior to or after forming.
NDE of welds in Grades WP5, WP9, WP91, WP911, WP22
Class 1, and WP22 Class 3 shall be done after forming.
6.3 Personnel performing NDE examinations shall be quali-
fied in accordance with SNT-TC-1A.
TABLE 1 Chemical Requirements
NOTE 1—All requirements are maximum unless otherwise indicated.
NOTE 2—Where an ellipsis (...) appears in this table, there is no requirement.
Grade and
Marking
SymbolA
Composition, %
Carbon Manganese Phospho-
rus, max
Sulfur,
max
Silicon Chromium Molybdenum Nickel Copper Others
WPBB,C,D,E,F 0.30 max 0.29–1.06 0.050 0.058 0.10 min 0.40 max 0.15 max 0.40 max 0.40 max Vanadium 0.08 max
WPCC,D,E,F 0.35 max 0.29–1.06 0.050 0.058 0.10 min 0.40 max 0.15 max 0.40 max 0.40 max Vanadium 0.08 max
WP1 0.28 max 0.30–0.90 0.045 0.045 0.10–0.50 . . . 0.44–0.65 . . . . . . . . .
WP12 CL1, 0.05–0.20 0.30–0.80 0.045 0.045 0.60 max 0.80–1.25 0.44–0.65 . . . . . . . . .
WP12 CL2 . . .
WP11 CL1 0.05–0.15 0.30–0.60 0.030 0.030 0.50–1.00 1.00–1.50 0.44–0.65 . . . . . . . . .
WP11 CL2, 0.05–0.20 0.30–0.80 0.040 0.040 0.50–1.00 1.00–1.50 0.44–0.65 . . . . . . . . .
WP11 CL3 . . .
WP22 CL1, 0.05–0.15 0.30–0.60 0.040 0.040 0.50 max 1.90–2.60 0.87–1.13 . . . . . . . . .
WP22 CL3 . . .
WP5 CL1, 0.15 max 0.30–0.60 0.040 0.030 0.50 max 4.0–6.0 0.44–0.65 . . . . . . . . .
WP5 CL3 . . .
WP9 CL1,
WP9 CL3
0.15 max 0.30–0.60 0.030 0.030 1.00 max 8.0–10.0 0.90–1.10 . . . . . . . . .
WPR 0.20 max 0.40–1.06 0.045 0.050 . . . . . . . . . 1.60–2.24 0.75–1.25 . . .
WP91 0.08–0.12 0.30–0.60 0.020 0.010 0.20–0.50 8.0–9.5 0.85–1.05 0.40 max . . . Vanadium 0.18–0.25
Columbium 0.06–0.10
Nitrogen 0.03–0.07
Aluminum 0.04 max
WP911 0.09–0.13 0.30–0.60 0.020 0.010 0.10–0.50 8.5–9.5 0.90–1.10 0.40 max . . . Vanadium 0.18–0.25
Columbium 0.060–0.10
Nitrogen 0.04–0.09
Aluminum 0.04 max
Boron 0.0003–0.006
Tungsten 0.90–1.10
A When fittings are of welded construction, the grade and marking symbol shown above shall be supplemented by letter “W”.
B Fittings made from bar or plate may have 0.35 max carbon.
C Fittings made from forgings may have 0.35 max carbon and 0.35 max silicon with no minimum.
D For each reduction of 0.01 % below the specified carbon maximum, an increase of 0.06 % manganese above the specified maximum will be permitted, up to a
maximum of 1.35 %.
E The sum of Copper, Nickel, Chromium, and Molybdenum shall not exceed 1.00 %.
F The sum of Chromium and Molybdenum shall not exceed 0.32 %.
A 234/A 234M – 05a
2
6.4 The welded joints of the fittings shall be finished in
accordance with the requirements of Paragraph UW-35 ( a) of
ASME Section VIII, Division 1.
6.5 All butt-weld tees manufactured by cold-forming meth-
od(s) shall be liquid penetrant or magnetic particle examined
by one of the methods specified in Supplementary Requirement
S52 or S53 in Specification A 960/A 960M. This examination
shall be performed after final heat treat. Only the side wall area
of the tees need be examined. This area is defined by a circle
that covers the area from the weld bevel of the branch outlet to
the center line of the body or run. Internal and external surfaces
shall be examined when size permits accessibility. No cracks
shall be permitted. Other imperfections shall be treated in
accordance with Section 13 on Surface Quality. After the
removal of any crack, the tee(s) shall be re-examined by the
original method. Acceptable tees shall be marked with the
symbol PT or MT, as applicable, to indicate compliance.
6.6 Stubends may be produced with the entire lap added by
the welding of a ring, made from plate or bar of the same alloy
grade and composition, to the outside of a straight section of
pipe, provided the weld is double welded, is a full penetration
TABLE 2 Tensile Requirements
NOTE 1—Where an ellipsis (...) appears in this table, there is no requirement.
Grade and Marking Symbol WPB
WPC,
WP11 CL2,
WP12 CL2 WP1
WP11 CL1,
WP22 CL1,
WP5 CL1
WP9 CL1
WPR
WP11 CL3,
WP22 CL3
WP5 CL3
WP9 CL3
WP91 WP911 WP12 CL1
Tensile strength, range ksi [MPa] 60–95
[415–655]
70–95
[485–655]
55–80
[380–550]
60–85
[415–585]
63–88
[435–605]
75–100
[520–690]
85–110
[585–760]
90–120
[620–840]
60–85
[415–585]
Yield strength, min, ksi [MPa]
(0.2 % offset or 0.5 %
extension-
under-load)
35 [240] 40 [275] 30 [205] 30 [205] 46 [315] 45 [310] 60 [415] 64 [440] 32 [220]
Elongation Requirements
Grades
All Grades except WPR,
WP91, and WP911 WPR
WP91
WP911
Longi-
tudinal
Trans-
verse
Longi-
tudinal
Trans-
verse
Longi-
tudinal
Trans-
verse
Elongation:
Standard round specimen, or small proportional specimen, min % in 4 D 22 14 20 . . . 20 . . .
Rectangular specimen for wall thickness 5⁄16 in. [7.94 mm] and over,
and for all small sizes tested in full section; min % in 2 in. [50 mm]
30 20A 28 . . . . . . . . .
Rectangular specimen for wall thickness less than 5⁄16 in. [7.94 mm];
min % in 2 in. [50 mm] (1⁄2-in. [12.7-mm] wide specimen)
B B B
. . . . . . . . .
A WPB and WPC fittings manufactured from plate shall have a minimum elongation of 17 %.
B For each 1⁄32 in. [0.79 mm] decrease in wall thickness below 5⁄16 in. [7.94 mm], a deduction of 1.5 % for longitudinal and 1.0 % for transverse from the values shown
above is permitted. The following table gives the minimum value for various wall thicknesses.
Wall Thickness
Grades
All Grades except WPR, WP91 and WP911 WPR WP91 and WP911
in. [mm] Longitudinal Transverse Longitudinal Longitudinal
5⁄16 (0.312) 7.94 30.0 20.0 28.0 20
9⁄32 (0.281) 7.14 28.5 19.0 26.5 19
1⁄4 (0.250) 6.35 27.0 18.0 25.0 18
7⁄32 (0.219) 5.56 25.5 . . . 23.5 17
3⁄16 (0.188) 4.76 24.0 . . . 22.0 16
5⁄32 (0.156) 3.97 22.5 . . . 20.5 15
1⁄8 (0.125) 3.17 21.0 . . . 19.0 14
3⁄32 (0.094) 2.38 19.5 . . . 17.5 13
1⁄16 (0.062) 1.59 18.0 . . . 16.0 12
Note—This table gives the computed minimum % elongation value for each 1⁄32 in. [0.79 mm] decrease in wall thickness. Where the wall thickness lies between two
values above, the minimum elongation value is determined by the following equations:
Direction of Test Equation
Longitudinal E= 48t + 15.00
Transverse E= 32t + 10.00
where:
E = elongation in 2 in. or [50 mm], %, and
t = actual thickness of specimen, in. [mm].
A 234/A 234M – 05a
3
joint, satisfies the requirements of 6.2 for qualifications and
7.3.3 for post weld heat treatment.
7. Heat Treatment
7.1 Heat Treatment Procedures—Fittings, after forming at
an elevated temperature, shall be cooled to a temperature
below the critical range under suitable conditions to prevent
injurious defects caused by too rapid cooling, but in no case
more rapidly than the cooling rate in still air. Heat treatment
temperatures specified are metal (part) temperatures. Heat-
treated fittings shall be treated according to paragraph 7 in
Specification A 960/A 960M.
7.2 WPB, WPC, and WPR Fittings:
7.2.1 Hot-formed WPB, WPC, and WPR fittings upon
which the final forming operation is completed at a temperature
above 1150 °F [620 °C] and below 1800 °F [980 °C] need not
be heat treated provided they are cooled in still air.
7.2.2 Hot-formed or forged WPB, WPC, and WPR fittings
finished at temperature in excess of 1800 °F [980 °C] shall
subsequently be annealed, normalized, or normalized and
tempered. Hot-forged fittings NPS 4 or smaller need not be
heat treated.
7.2.3 WPB, WPC, and WPR fittings over NPS 12, produced
by locally heating a portion of the fitting stock to any
temperature for forming, shall be subsequently annealed,
normalized, or normalized and tempered. Fittings such as
elbows, tees, header tees, reducers and lap joint stub ends with
a carbon content less than 0.26 %, NPS 12 and under, shall not
require heat treatment after forming a locally heated portion of
the fitting.
7.2.4 Cold-formed WPB, WPC, and WPR fittings, upon
which the final forming operation is completed at a temperature
below 1150 °F [620 °C], shall be normalized, or shall be stress
relieved at 1100 to 1275 °F [595 to 690 °C].
7.2.5 WPB, WPC, and WPR fittings produced by fusion
welding and having a nominal wall thickness at the welded
joint of 3⁄4 in. [19 mm] or greater shall be post-weld heat treated
at 1100 to 1250 °F [595 to 675 °C], or in accordance with 7.2.6.
7.2.6 At the option of the manufacturer, WPB and WPC
fittings produced by any of the methods in Section 6 may be
annealed, normalized, or normalized and tempered.
7.3 Fittings Other than WPB, WPC, and WPR:
7.3.1 Fittings of Grades WP1, WP11 Class 1, WP11 Class 2,
WP11 Class 3, WP12 Class 1, WP12 Class 2, WP22 Class 1,
WP22 Class 3, WP5, and WP9 shall be furnished in the
full-annealed, isothermal-annealed, or normalized and tem-
pered condition. If normalized and tempered, the tempering
temperature for WP11 Class 1, WP11 Class 2, WP11 Class 3,
WP12 Class 1, and WP12 Class 2 shall not be less than 1150
°F [620 °C]; for Grades WP5, WP9, WP22 Class 1, and WP22
Class 3 the tempering temperature shall not be less than 1250
°F [675 °C].
7.3.2 Fittings of Grades WP1, WP12 Class 1, or WP12
Class 2 either hot formed or cold formed may be given a final
heat treatment at 1200 °F [650 °C] instead of the heat treatment
specified in 7.3.1.
7.3.3 Fittings in all thicknesses produced by fusion welding
after the heat treatment specified in 7.3.1 shall be post-weld
heat treated at a temperature not less than prescribed above for
tempering except that Grade WP1 is required to be post-weld
heat treated only when the nominal wall thickness at the
welded joint is 1⁄2 in. [13 mm] or greater.
7.3.4 Except when Supplementary Requirement S1 is speci-
fied by the purchaser, Grade WP91 shall be normalized at 1900
°F [1040 °C] minimum, and 1975 °F [1080 °C] maximum, and
tempered in the temperature range of 1350 °F [730 °C] to 1470
°F [800 °C] as a final heat treatment.
7.3.5 Grade WP911 shall be normalized in the temperature
range of 1900 to 1975 °F [1040 to 1080 °C], and tempered in
the temperature range of 1365 to 1435 °F [740 to 780 °C] as a
final heat treatment.
7.4 WPB and WPC Fittings Made from Bar— Cold-finished
bars reduced in cross-sectional area more than 10 % by cold
drawing or cold rolling are not acceptable for use in the
manufacture of these fittings unless the bars have been either
stress relieved in the temperature range of 1100 to 1250 °F
[595 to 675 °C], normalized, normalized and tempered, or fully
annealed. Mechanical testing must be performed subsequent to
the final heat-treating operation.
7.5 Liquid quenching followed by tempering shall be per-
mitted for all grades when approved by the purchaser. Mini-
mum tempering temperature shall be 1100 °F [595 °C] for
WPB, WPC, and WPR, 1150 °F [620 °C] for Grades WP1,
WP11 Class 1, WP11 Class 2, WP11 Class 3, WP 12 Class 1,
and WP12 Class 2 and 1250 °F [675 °C] for Grades WP5,
WP9, WP22 Class 1, and WP22 Class 3, and 1350 °F [730 °C]
for Grade WP91 and WP911.
8. Chemical Composition
8.1 The chemical composition of each cast or heat used
shall be determined and shall conform to the requirements of
the chemical composition for the respective materials listed in
Table 1. The ranges as shown have been expanded to include
variations of the chemical analysis requirements that are listed
in the various specifications for the starting materials (pipe,
tube, plate, bar, and forgings) normally used in the manufac-
turing of fittings to this specification.
8.2 The steel shall not contain any unspecified elements for
the ordered grade to the extent that it conforms to the
requirements of another grade for which that element is a
specified element having a required minimum content.
8.3 Weld metal used in the construction of carbon-steel
fittings shall be mild steel analysis No. A1 of Table QW-442,
Section IX of the ASME Boiler and Pressure Vessel Code, No.
A2 may be used for Grade WPCW.
8.4 The molybdenum and chromium content of the depos-
ited weld metal of alloy steel fittings shall be within the same
percentage range as permitted for the base metal.
9. Tensile Requirements Tensile Requirements
9.1 The tensile properties of the fitting material shall con-
form to the requirements listed in Table 2.
9.1.1 Specimens cut either longitudinally or transversely
shall be acceptable for the tension test.
9.1.2 While Table 2 specifies elongation requirements for
both longitudinal and transverse specimens, it is not the intent
that both requirements apply simultaneously. Instead, it is
A 234/A 234M – 05a
4
intended that only the elongation requirement that is appropri-
ate for the specimen used be applicable.
9.2 One tension test shall be made on each heat of
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