ASTM A381/A381M-23

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: A381/A381M − 18 A381/A381M − 23
Standard Specification for
Metal-Arc-Welded Carbon or High-Strength Low-Alloy Steel
Pipe for Use With High-Pressure Transmission Systems
This standard is issued under the fixed designation A381/A381M; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers straight seam, double-submerged-arc-welded carbon or high-strength low-alloy steel pipe (Note 1)
5 1
suitable for high-pressure service, 16 in. [400 mm] and larger in outside diameter, with wall thicknesses from ⁄16 to 1 ⁄2 in. [8 to
40 mm]. The pipe is intended for fabrication of fittings and accessories for compressor or pump-station piping. Pipe ordered to this
specification shall be suitable for bending, flanging, corrugating, and similar operations.
NOTE 1—A comprehensive listing of standardized pipe dimensions is contained in ANSI B36.10.
NOTE 2—The term “double welded” is commonly used in the gas and oil transmission industry, for which this pipe is primarily intended, to indicate
welding with at least two weld passes, of which one is on the outside of the pipe and one on the inside. For some sizes of the pipe covered by this
specification, it becomes expedient to use manual welding, in which case the provisions of Note 3 shall be followed.
1.2 This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract
specifies the applicable M specification designation (SI units), the applicable inch-pound units shall apply. 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 may not be exact equivalents; therefore, each system shall be used independently of the other.
Combining values from the two systems may result in nonconformance with the standard.
1.3 Eleven classes of pipe, based on minimum yield point requirements, are covered as indicated in Table 1.
1.4 This specification identifies various thermal treatments (3.1.94.1.9, 5.56.5, and 5.66.6).
1.5 The following caveat applies to the test methods portion, Sections 910, 1011, and 1112, only. This standard does not purport
to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish
appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.09
on Carbon Steel Tubular Products.
Current edition approved Nov. 1, 2018Nov. 1, 2023. Published December 2018November 2023. Originally approved in 1954. Last previous edition approved in 20122018
as A381 – 96A381/A381M – 18. (2012). DOI: 10.1520/A0381_A0381M-18.10.1520/A0381_A0381M-23.
*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
A381/A381M − 23
TABLE 1 Tensile Requirements
Class Yield Strength, Tensile Strength, Elongation in 2 in.
min, psi [MPa] min, psi [MPa] [50 mm],
min, %
Y 35 35 000 [240] 60 000 [415] 26
Y 42 42 000 [290] 60 000 [415] 25
Y 46 46 000 [316] 63 000 [435] 23
Y 48 48 000 [330] 62 000 [430] 21
Y 50 50 000 [345] 64 000 [440] 21
Y 52 52 000 [360] 66 000 [455] 20
Y 56 56 000 [385] 71 000 [490] 20
Y 60 60 000 [415] 75 000 [515] 20
Y 65 65 000 [450] 77 000 [535] 20
Y 70 70 000 [485] 82 000 [565] 18
Y 80 80 000 [550] 90 000 [620] 16
2. Referenced Documents
2.1 ASTM Standards:
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A530/A530M Specification for General Requirements for Specialized Carbon and Alloy Steel Pipe
A751 Test Methods and Practices for Chemical Analysis of Steel Products
A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
A1058 Test Methods for Mechanical Testing of Steel Products—Metric
2.2 ASME Boiler and Pressure Vessel Code:
Section VIII
Section IX
2.3 ASME Standard:
ASME B36.10 Welded and Seamless Wrought Steel Pipe
3. Terminology
3.1 Definitions of Terms—For definitions of terms used in this standard, refer to:
3.1.1 Terminology A941 for general steel terminology,
3.1.2 Test Methods and Definitions A370 or Test Methods A1058 for mechanical testing of steel products terminology, and
3.1.3 Test Methods and Practices A751 for chemical analysis of steel products terminology.
4. Ordering Information
4.1 Orders for metal-arc-welded steel pipe to this specification should include the following, as required, to describe the desired
material adequately:
4.1.1 Quantity (feet, centimetres, or number of lengths),
4.1.2 Name of material (metal-arc welded pipe),
4.1.3 Class (Table 1),
4.1.4 Material (carbon or high-strength low-alloy steel, Section 56),
4.1.5 Size (outside diameter and wall thickness),
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.
Available from American Society of Mechanical Engineers, 345 E. 47th St., New York, NY 10017.
Available from American Society of Mechanical Engineers (ASME), ASME International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
www.asme.org.
A381/A381M − 23
4.1.6 Length (specific or random) (Section 1314),
4.1.7 Ends (Section 1415),
4.1.8 Heat treatment (stress-relieved, normalized, or quenched and tempered) (see 5.56.5 and 5.66.6),
4.1.9 Optional requirements:
4.1.9.1 Manual welding (5.26.2, Note 3),
4.1.9.2 Hydrostatic test omission (9.310.3),
4.1.9.3 Radiography (11.212.2).
4.1.10 ASTM Specification designation A381 or A381M and year date.
4.1.11 Special requirements or exceptions to this specification.
5. General Requirements
5.1 Material furnished to this specification shall conform to the applicable requirements of the current edition of Specification
A530/A530M, unless otherwise provided herein.
6. Materials and Manufacture
6.1 The steel plate used in the manufacture of the pipe shall be of suitable welding quality carbon steel, or of suitable welding
quality high-strength, low-alloy steel, as agreed upon between the manufacturer and purchaser.
6.2 The longitudinal edges of the plate shall be shaped to give the most satisfactory results by the particular welding process
employed. The plate shall be properly formed and may be tacked preparatory to welding. The weld (except tack welds) shall be
made preferably by the automatic submerged-arc-welding process (Note 3) and shall be of reasonably uniform width and height
for the entire length of the pipe.
NOTE 3—By agreement between the manufacturer and the purchaser, manual welding by qualified welders using a qualified procedure may be used as
an equal alternate to this specification.
6.3 Both longitudinal and circumferential (if any) joints shall be double welded, full penetration welds being made in accordance
with procedures and by welders or welding operators qualified in accordance with the ASME Boiler and Pressure Vessel Code,
Section IX.
6.4 The contour of the reinforcement shall be smooth, with no valley or groove along the edge or in the center of the weld, and
the deposited metal shall be fused smoothly and uniformly into the plate surface. The finish of the welded joint shall be reasonably
smooth and free from irregularities, grooves, or depressions.
6.5 All pipe, after welding, shall be heat treated at a temperature of 1100°F [595°C] or higher.
6.6 When specified in the purchase order, all pipe after welding shall be heated at 1650 to 1750°F [900 to 955°C] and air cooled
or water quenched and tempered. Tempering temperature shall not exceed the lower transformation temperature.
7. Chemical Composition
7.1 The carbon steels shall conform to the requirements as to chemical composition specified in Table 2.
7.2 The high-strength low-alloy steels shall be of specified chemical composition in order to ensure weldability and specified
minimum tensile properties including elongation.
A381/A381M − 23
TABLE 2 Chemical Requirements for Carbon Steels on Product
Analysis
Element Composition, %, max
Ladle Check
Carbon 0.26 0.30
Manganese 1.40 1.50
Phosphorus 0.025 0.030
Sulfur 0.025 0.025
7.3 Mill test reports, as provided by the manufacturer of the plate, shall be furnished representing the chemical analysis of each
heat of steel from which the plates are rolled. This chemical analysis shall conform to the requirements of 5.16.1, 6.17.1, or 6.27.2.
7.4 For product analyses, Test Methods and Practices A751 shall be used.
8. Tensile Requirements
8.1 The tensile properties of transverse body-test specimens shall conform to the requirements prescribed in Table 1. The tensile
strength of the weld-test specimens shall conform to that specified in Table 1.
8.2 Transverse body-test specimens shall be taken approximately opposite the weld; transverse weld-test specimens shall be taken
with the weld at the center of the specimen. For pipe wall thicknesses up to ⁄4 in. [19 mm], incl, all test specimens shall be in
accordance with Test Methods and Definitions A370 using full-size specimens or the largest obtainable sub-s
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