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GB/T 31940-2025Bi-metal composite steel pipes for fluid transportation (English PDF)

输送流体用双金属复合钢管

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Issued by

SAMR; SAC

Level / Type

National · Recommended

Issue date

August 1, 2025

Implementation date

February 1, 2026

Scope

GB/T 31940-2025 is the English-translated version of 输送流体用双金属复合钢管.

GB/T 31940-2025 is the Chinese standard "Bi-metal composite steel pipes for fluid transportation". Its scope clause reads: This document specifies the classification and code, ordering content, manufacturing process, and specifications of bimetallic composite steel pipes for conveying fluids (hereinafter referred to as composite steel pipes).

Process, technical requirements, test methods, inspection rules, marking, packaging, storage and quality certificate. This document is applicable to composite steel pipes used to transport domestic water, fire water, air conditioning water, recycled water, sewage and waste water, as well as water conservancy projects.

Composite steel pipes for pipeline engineering, transportation of steam, gas, air, etc. and composite steel pipes for onshore oil and gas transportation, oil well gathering and transportation, and chemical pipelines.

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Document preview — GB/T 31940-2025

National Standard of the People's Republic of China

ICS: 77.140.75
Classification: H 48
Replacing: GB/T 31940-2015

Issued by: State Administration for Market Regulation; Standardization Administration of the PRC

Preface
1 Scope
2 Normative references
3 Terms and Definitions
4 Symbols and abbreviations
5 Classification and Code
6 Order Content
7 Manufacturing Process
8 Technical Requirements
9 Test Methods
10 Inspection Rules
11 Labeling, packaging, storage and quality certificate
Appendix B (Informative) Calculation of the specified values of tensile properties of composite steel pipes
Appendix C (Normative) Bimetallic Composite Pipe Fittings
Appendix D (Informative) Outer diameter and wall thickness of threaded and grooved composite steel pipes
Appendix E (Normative) Test Method for Interface Shear Bond Strength of Lined Composite Steel Pipe
Appendix F (Normative) Residual Compressive Stress Test Method
Appendix G (Normative) Test method for corrosion resistance of interfaces
Appendix H (Normative) Hot and cold cycle performance test method

1 Scope

This document specifies the classification and code, ordering content, manufacturing process, and specifications of bimetallic composite steel pipes for conveying fluids (hereinafter referred to as composite steel pipes).

Process, technical requirements, test methods, inspection rules, marking, packaging, storage and quality certificate.

This document is applicable to composite steel pipes used to transport domestic water, fire water, air conditioning water, recycled water, sewage and waste water, as well as water conservancy projects.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to

This document.

GB/T 222 Permissible deviations of chemical composition of finished steel products

GB/T 228.1 Tensile tests on metallic materials - Part 1.Room temperature test methods

GB/T 229 Charpy pendulum impact test method for metallic materials

GB/T 241 Hydraulic test method for metallic pipes

GB/T 246 Flattening test method for metallic tubes

GB/T 700 Carbon Structural Steel

GB/T 983 Stainless steel welding rods

GB/T 1591 Low alloy high strength structural steel

GB/T 2102 Acceptance, packaging, marking and quality certificate of steel pipes

GB/T 2651 Destructive tests on welds of metallic materials - Transverse tensile tests

GB/T 2653 Bend test method for welded joints

GB/T 2828.1 Sampling procedures for inspection by attributes Part 1.Sampling plans for batch inspection based on acceptance quality limit (AQL)

GB/T 2975 Sampling location and specimen preparation for mechanical property tests on steel and steel products

GB/T 3091 Welded steel pipes for low-pressure fluid transportation

GB/T 3287 Malleable cast iron pipe fittings

GB/T 4334 Corrosion of metals and alloys - Test method for intergranular corrosion of austenitic and ferritic-austenitic (duplex) stainless steels

GB/T 4336 Carbon steel and medium and low alloy steel - Determination of multi-element content - Spark discharge atomic emission spectrometry (conventional method)

GB/T 4340.1 Metallic materials Vickers hardness test Part 1.Test method

GB/T 5117 Welding rods for non-alloy steel and fine grain steel

GB/T 5118 Heat-resistant steel welding rods

GB 5135.11 Automatic sprinkler systems Part 11.Grooved pipe fittings

GB/T 5293 Classification requirements for solid welding wires, flux-cored welding wires and wire-flux combinations for non-alloy steel and fine-grained steel for submerged arc welding

GB/T 5310 Seamless steel tubes for high-pressure boilers

GB/T 5777 Full circumferential automatic ultrasonic testing of seamless and welded (except submerged arc welded) steel for longitudinal and/or transverse imperfections

GB/T 6396 Test methods for mechanical and process properties of composite steel plates

GB/T 7306.2 55° sealing pipe threads Part 2.Conical internal threads and conical external threads

GB/T 32970 | GB/T 32957 | GB/T 32569 | GB/T 31941 | GB/T 31937 | […]

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 40 pages — is available in the English PDF.

Referenced standards

Normative references

Cited by

Editions of GB/T 31940

Edition	Title	Revision	Status
GB/T 31940-2025	Bi-metal composite steel pipes for fluid transportation	current edition	Current
GB/T 31940-2015	Bi-metal composite corrosion resistance steel pipe for fluid transportation	previous edition	In force

This page sells the current edition, GB/T 31940-2025. Earlier editions are listed for reference only.

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