GB/T 2975-2018 (English Version)

Standard No.: GB/T 2975-2018
Language: Chinese, Available in English version
Release Date: 2018
Published By: General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest: GB/T 2975-2018
Replace: GB/T 2975-1998

Scope: This standard specifies the requirements for identification, sampling location and preparation of test specimens for mechanical property tests of shaped steel, bars, wire rods, steel plates and pipes defined in GB/T 15574. This standard applies to the sampling and preparation of mechanical properties of steel and steel products. This standard also applies to other metal products, if specified in the contract. These samples and samples may be tested in accordance with relevant product standards, material standards or test standards.

Introduction

Analysis of the core content of the standard

Major technical changes

Change dimensions	1998 version	2018 version
Terminology specification	Leg/waist	Flange/web
Steel plate sampling	25mm≤t<50mm separate regulations	Uniform t≥25mm requirement
Machining allowance	Minimum 20mm	Reduced to 12.5mm
New Content	-	TMCP Steel Plate/Laser Cutting Requirements

Key Technical Points

1. Principle of Sampling Representativeness

According to the requirements of Chapter 4 of the standard, the sample selection should ensure that it can reflect the overall performance characteristics of products such as steel sections and steel plates, with special attention to:

Avoidance of heat-affected zone (≥12.5mm allowance must be retained for the burning cutting method)
Rolling direction identification (L/T directions must be clearly marked)
Thickness gradient sampling (for plates with t≥40mm)

Typical Application Case: TMCP Steel Plate Sampling

For Thermomechanically rolled steel plate, standard A.6.2.2 specifically stipulates:

The specimen thickness should be full thickness or 1/2 thickness
When 1/2 thickness specimen is used, the original 30mm lower limit requirement becomes invalid
The center line of the specimen must be strictly aligned with the thickness center line

Implementation Recommendations

1. Transition Plan between the Old and New Standards

Project	Implementation Points
Terminology update	The expression "flange/web" is updated synchronously in the technical documents
Allowance control	Laser cutting shall be carried out in accordance with Table B.2 (1-3mm)
Specimen identification	Add digital traceability methods such as QR code

2. Handling of special situations

When encountering special-shaped steel sampling, please note:

Steel with inclined flanges shall be sampled on the web first (A.2.1.2)
Unequal-leg angle steel may select any flange (A.2.1.4)
The sampling position of T-shaped steel needs to be reconfirmed (revise Figure A.1c)

Analysis of Standard Evolution

This standard adopts ISO 377:2017 through modification. The main technical differences are:

Added surface requirements for bending test specimens (the original surface must be retained)
Refined the sampling provisions for longitudinally rolled steel plates (A.6.1.3)
Adjusted the diagram for T-section steel sampling (Figure A.1c)

These adjustments are more in line with the actual production and testing needs of domestic steel companies, reflecting the optimization of technical adaptability in the process of standard localization.

GB/T 2975-2018 Referenced Document

GB/T 15574 Steel products classification
GB/T 20832 Metallic materials Designation of test specimen axes in relation to product texture

GB/T 2975-2018 history

2018 GB/T 2975-2018 Steel and steel products - Location and preparation of samples and test pieces for mechanical testing
1998 GB/T 2975-1998 Steel and steel products--Location and preparation of test pieces for mechanical testing
0000年 GB 2975-1982