GB/T 5312-2025 Seamless steel tubes and pipes for ship Seamless steel tubes and pipes for ship
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ICS 77.140.75 CCS H48
National Standard of the People's Republic of China
GB/T 5312-2025
Replacing GB/T 5312-2009, GB/T 31928-2015
Seamless Steel Tubes and Pipes for Ship
Issued: 2025-08-29
Implemented: 2026-03-01
Issued by:
State Administration for Market Regulation
Standardization Administration of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions, Symbols
4 Classification and Designation
5 Ordering Information
6 Manufacturing Process
7 Technical Requirements
8 Test Specimens
9 Test Methods
10 Inspection Rules
11 Packing, Marking and Quality Certificate
Appendix A (Informative) Optional Special Requirements for Orders
Appendix B (Informative) High Temperature Specified Plastic Extension Strength
References
Seamless Steel Tubes and Pipes for Ship
1 Scope
This document specifies the classification, designation, ordering information, manufacturing process, technical requirements, inspection rules, packing, marking and quality certificate for seamless steel tubes and pipes for ship, and describes the corresponding test methods.
This document is applicable to seamless steel tubes and pipes (hereinafter referred to as tubes) for ship pressure piping systems, boilers and superheaters made of carbon steel, carbon-manganese steel, alloy steel and stainless steel.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute essential provisions of this document. For dated references, only the editions cited apply; for undated references, the latest edition (including any amendments) applies.
GB/T 222 Steel and alloy - Permissible tolerances for chemical composition of finished products
GB/T 223.9 Steel and alloy - Determination of aluminum content - Chrome azurol S spectrophotometric method
GB/T 223.11 Steel and alloy - Determination of chromium content - Visual titration or potentiometric titration method
GB/T 223.12 Methods for chemical analysis of steel and alloy - Determination of chromium content - Separation by sodium carbonate and spectrophotometric measurement with diphenylcarbazide
GB/T 223.18 Steel and alloy - Determination of copper content - Separation with sodium thiosulfate and iodometric method
GB/T 223.23 Steel and alloy - Determination of nickel content - Dimethylglyoxime spectrophotometric method
GB/T 223.25 Methods for chemical analysis of steel and alloy - Determination of nickel content - Dimethylglyoxime gravimetric method
GB/T 223.26 Steel and alloy - Determination of molybdenum content - Thiocyanate spectrophotometric method
GB/T 223.28 Methods for chemical analysis of steel and alloy - Determination of molybdenum content - α-Benzoylphenyloxime gravimetric method
GB/T 223.36 Steel and alloy - Determination of nitrogen content - Distillation separation and neutralization titration method
GB/T 223.40 Steel and alloy - Determination of niobium content - Chlorosulfonazo S spectrophotometric method
GB/T 223.50 Methods for chemical analysis of steel and alloy - Determination of tin content - Direct photometric method with phenylfluorone and cetyltrimethylammonium bromide
GB/T 223.53 Steel and alloy - Determination of copper content - Flame atomic absorption spectrophotometric method
GB/T 223.59 Steel and alloy - Determination of phosphorus content - Bismuth phosphomolybdate blue and antimony phosphomolybdate blue spectrophotometric methods
GB/T 223.60 Steel and alloy - Determination of silicon content - Gravimetric method
GB/T 223.63 Steel and alloy - Determination of manganese content - Sodium periodate (potassium) spectrophotometric method
GB/T 223.84 Steel and alloy - Determination of titanium content - Diantipyrylmethane spectrophotometric method
GB/T 223.85 Steel and alloy - Determination of sulfur content - Infrared absorption method after combustion in induction furnace
GB/T 223.86 Steel and alloy - Determination of total carbon content - Infrared absorption method after combustion in induction furnace
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at ambient temperature
GB/T 229 Metallic materials - Charpy pendulum impact test
GB/T 230.1 Metallic materials - Rockwell hardness test - Part 1: Test method
GB/T 231.1 Metallic materials - Brinell hardness test - Part 1: Test method
GB/T 232 Metallic materials - Bend test
GB/T 241 Metallic tubes - Hydraulic test
GB/T 242 Metallic tubes - Flaring test
GB/T 246 Metallic tubes - Flattening test
GB/T 2102 Acceptance, packing, marking and quality certificate for steel tubes
GB/T 2975 Steel and steel products - Location and preparation of test pieces for mechanical testing
GB/T 4334-2020 Corrosion of metals and alloys - Intergranular corrosion test for austenitic and ferritic-austenitic (duplex) stainless steels
GB/T 4336 Carbon steel and medium-low alloy steel - Determination of multi-element contents - Spark discharge atomic emission spectrometry (routine method)
GB/T 5777 Automatic ultrasonic testing for full circumference discontinuities of seamless and welded (except submerged arc) steel tubes - Longitudinal and/or transverse
GB/T 7735 Automatic eddy current testing for discontinuities of seamless and welded (except submerged arc) steel tubes
GB/T 11170 Stainless steel - Determination of multi-element contents - Spark discharge atomic emission spectrometry (routine method)
GB/T 12606 Automatic magnetic flux leakage testing for full circumference discontinuities of seamless and welded (except submerged arc) ferromagnetic steel tubes - Longitudinal and/or transverse
GB/T 13305 Determination of α-phase content in stainless steel
GB/T 17395 Dimensions, shape, weight and tolerances for steel tubes
GB/T 20066 Steel and iron - Sampling and sample preparation for chemical analysis
GB/T 20123 Steel - Determination of total carbon and sulfur contents - Infrared absorption method after combustion in high frequency induction furnace (routine method)
GB/T 20124 Steel - Determination of nitrogen content - Inert gas fusion thermal conductivity method (routine method)
GB/T 20125 Low alloy steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometry
GB/T 30062 Steel tube terminology
GB/T 39077 Detection of harmful phases in austenitic-ferritic (duplex) stainless steel
YB/T 4395 Steel - Determination of molybdenum, niobium and tungsten contents - Inductively coupled plasma atomic emission spectrometry
YB/T 4396 Stainless steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometry
3 Terms and Definitions, Symbols
3.1 Terms and Definitions
The terms and definitions defined in GB/T 30062 apply to this document.
3.2 Symbols
The following symbols apply to this document.
D - Outside diameter or nominal outside diameter, in millimeters (mm)
S - Wall thickness or nominal wall thickness, in millimeters (mm)
Smin - Minimum wall thickness, in millimeters (mm)
d - Nominal inside diameter, in millimeters (mm)
4 Classification and Designation
4.1 Tubes are classified into two categories according to their use: pressure piping system tubes and boiler/superheater tubes. Pressure piping system tubes are divided into 3 grades according to design pressure and design temperature, as shown in Table 1. Their categories, grades and designations are:
a) Grade I pressure piping system tubes (hereinafter referred to as Grade I pressure tubes), designated as I;
b) Grade II pressure piping system tubes (hereinafter referred to as Grade II pressure tubes), designated as II;
c) Grade III pressure piping system tubes (hereinafter referred to as Grade III pressure tubes), designated as III;
d) Boiler/superheater tubes, designated as G.
