GB/T 232-2024
Metallic materials - Bend test methods (English Version)

Standard No.

GB/T 232-2024

Language

Chinese, Available in English version

Release Date

2024

Published By

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China  CN  /  GB

Latest

GB/T 232-2024

Replace

GB/T 232-2010

Introduction

1. Background of the standard and necessity of its formulation

GB/T 232-2024 "Method of bending test for metallic materials" is a revised version of the original standard GB/T 232-2010. It mainly combines the technical requirements of ISO 7438:2020 and makes adaptive adjustments based on China's national conditions. This revision focuses on solving the following problems:

• Improve the specimen preparation specifications
• Add the bending test method under plane strain conditions
• Optimize the stress triaxiality calculation formula
• Clarify the requirements for the indenter diameter and displacement measurement

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2. Comparative analysis of standard frameworks

Standard content	GB/T 232-2010	GB/T 232-2024（New）
Test equipment requirements	The calculation formula for the support roller spacing is not clarified	Add formula (1) to determine the support roller spacing, the maximum shall not exceed d+2a
Specimen preparation requirements	Specimen width under plane strain conditions is not specified	Add clause 7.3 to clarify the requirement of p/a≥10
Test result evaluation	The influence of stress triaxiality is not considered	Add clause A.2 to specify the calculation method of Lode angle parameters

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3. Interpretation of core technical points

3.1 Bending test equipment configuration requirements

GB/T 232-2024 specifies four main bending devices:

• Roller bending device: The length of the roller and the width of the bending pressure head must be greater than the specimen size
• V-type die bending device: the angle should be 180°±θ, and the fillet radius should be reasonably controlled
• Vise-type bending device: the left end surface should not exceed the vertical line of the center of the pressure head
• Other devices that conform to the principle: such as the plate type, etc., must meet the basic technical requirements

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4. Implementation suggestions and precautions

4.1 Precautions for specimen preparation

Pay special attention to the following points:

• The fillet radius shall not exceed 5% of the specimen thickness
• The tolerance of the machined surface shall be ≤25mm
• The specimen width under plane strain conditions shall be ≥10 times the thickness

4.2 Test process control suggestions

It is recommended that in actual operation:

• Calculate the roller spacing strictly according to formula (1)
• Record all sample parameters for easy traceability analysis
• Use finite element simulation to verify the bending stress distribution