GB/T 14975-2025 Seamless stainless steel tubes for structure
1 Scope
This document specifies the classification and designation, order content, manufacturing process, technical requirements, test methods, inspection rules, packaging, marking, and quality certificate for seamless stainless steel tubes for structure.
This document is applicable to seamless stainless steel tubes (hereinafter referred to as the steel tubes) for general structures or mechanical structures.
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 222 Steel and alloy - Permissible tolerances for chemical composition of products
GB/T 223.4 Steel, iron and alloy - Determination of manganese content - Potentiometric or visual titration method
GB/T 223.9 Iron steel and alloy - Determination of aluminium content - Chrom azurol S photometric method
GB/T 223.11 Steel, iron and alloy - Determination of chromium content - Visual titration or potentiometric titration method
GB/T 223.18 Methods for chemical analysis of steel, iron and alloy - The sodium thiosulfate separation iodimetric method for the determination of copper content
GB/T 223.19 Methods for chemical analysis of steel, iron and alloy - The neocuproine-chloroform extraction photometric method for the determination of copper content
GB/T 223.23 Steel, iron and alloy - Determination of nickel content - The dimethylglyoxime spectrophotometric method
GB/T 223.25 Methods for chemical analysis of iron, steel and alloy - The dimethylglyoxime gravimetric method for the determination of nickel content
GB/T 223.26 Steel, iron and alloy - Determination of molybdenum content - The thiocyanate spectrophotometric method
GB/T 223.28 Methods for chemical analysis of steel, iron and alloy - The D-denzoinoxime gravimetric method for the determination of molybdenum content
GB/T 223.36 Methods for chemical analysis of iron, steel and alloy - The neutral titration method for the determination of nitrogen content after distillation separation
GB/T 223.37 Steel, iron and alloy - Determination of nitrogen content - Indophenol blue spectrophotometric method after distillation separation
GB/T 223.40 Steel, iron and alloy - Determination of niobium content by the sulphochlorophenol S spectrophotometric method
GB/T 223.59 Steel, iron and alloy - Determination of phosphorus content - Bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method
GB/T 223.60 Steel, iron and alloy - Determination of silicon content - Gravimetric method
GB/T 223.63 Steel, iron and alloy - Determination of manganese content - Sodium(potassium) periodate spectrophotometric method
GB/T 223.84 Steel, iron and alloy - Determination of titanium content - Diantipyrylmethane spectrophotometric method
GB/T 223.85 Steel, iron and alloy - Determination of sulfur content - Infrared absorption method after combustion in an induction furnace
GB/T 223.86 Steel, iron and alloy - Determination of total carbon content - Infrared absorption method after combustion in an induction furnace
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
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 241 Metallic materials - Tube - Hydrostatic pressure test
GB/T 242 Metal materials - Tube - Drift-expending test
GB/T 246 Metallic materials - Tube - Flattening test
GB/T 2102 Acceptance, packaging, marking and quality certification for steel tubular products
GB/T 2975 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing
GB/T 4334-2020 Corrosion of metals and alloys - Test methods for intergranular corrosion of austenitic and ferritic-austenitic (duplex) stainless steels
GB/T 4340.1 Metallic materials - Vickers hardness test - Part 1: Test method
GB/T 5777 Automated full peripheral ultrasonic testing of seamless and welded(except submerged arc-welded) steel tubes for the detection of longitudinal and/or transverse imperfections
GB/T 7735 Automated eddy current testing of seamless and welded (except submerged arc-welded) steel tubes for detection of imperfections
GB/T 11170 Stainless steel - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (routine method)
GB/T 17395 Dimensions, shapes, masses and tolerances of steel tubes
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition
GB/T 20123 Steel and iron - Determination of total carbon and sulfur content - Infrared absorption method after combustion in an induction furnace (routine method)
GB/T 20124 Steel and iron - Determination of nitrogen content - Thermal conductimetric method after fusion in a current of inert gas
GB/T 30062 Terminology of steel pipes and tubes
YB/T 4395 Steel - Determination of molybdenum, niobium and tungsten contents- Inductively coupled plasma atomic emission spectrometric method
YB/T 4396 Stainless steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometric method
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 30062 apply.
4 Classification and codification
4.1 Steel tubes are classified into two categories based on their manufacturing processes, with the following categories and codes:
a) Cold-rolled (drawn) steel pipes, designated as W-C;
b) Hot-rolled (extruded, forged, expanded) steel pipes, designated as W-H.
4.2 Steel pipes are classified into two grades based on dimensional accuracy, with their grades and codes as follows:
a) Standard grade, designated as PA;
b) High grade, designated as PC.
4.3 For the purposes of this document, the following symbols apply.
D Outer diameter (unless otherwise specified, including nominal outer diameter and/or calculated outer diameter, mm)
Dc Calculated outer diameter (the value of the outer diameter calculated by adding the nominal inner diameter and the nominal wall thickness, mm)
d Nominal inner diameter (mm)
S Wall thickness (unless otherwise specified, including nominal wall thickness and/or average wall thickness, mm)
Sc Average wall thickness (the mean value of the maximum and minimum wall thicknesses calculated based on the minimum wall thickness and its permissible deviation, mm)
Smin Minimum wall thickness (mm)
5 Order information
The contract or order for ordering steel tubes according to this document shall include the following contents:
a) No. of this document;
b) product name;
c) steel designation or unified numerical code;
d) dimension and specification;
e) quantity ordered (total weight or total length);
f) delivery status;
g) special requirements.
6 Manufacturing process
6.1 Steelmaking processes
Steel shall be smelted using the processes of electric arc furnace and external refining, converter and external refining, or electric slag remelting. After negotiation between the supplier and the purchaser and being specified in the contract, other methods of steelmaking may be adopted.
6.2 Manufacturing method of steel tubes
Steel tubes shall be manufactured using seamless methods such as cold rolling (drawing) or hot rolling (extrusion, forging, expansion). When the purchaser specifies a certain manufacturing method, it shall be specified in the contract.
6.3 Delivery condition
6.3.1 Steel tubes shall be delivered in a heat-treated and acid washed state. Steel tubes that have undergone overall grinding, boring, or protective atmosphere heat treatment may be delivered without acid washing. The recommended heat treatment system for steel tubes is shown in Table 1.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Classification and codification
5 Order information
6 Manufacturing process
6.1 Steelmaking processes
6.2 Manufacturing method of steel tubes
6.3 Delivery condition
7 Technical requirements
7.1 Steel designations and chemical composition
7.2 Mechanical properties
7.3 Technological properties
7.4 Hydraulic pressure
7.5 Intergranular corrosion
7.6 Surface quality
7.7 Dimension, shape and weight
8 Test methods
9 Inspection rules
9.1 Inspection and acceptance
9.2 Batching rules
9.3 Sampling quantity
9.4 Re-inspection and judgment rules
10 Packaging, marking and quality certificate
