GB/T 24179-2023Metallic materials—Residual stress determination—Indentation strain-gage method (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document replaces GB/T 24179-2009 "Indentation strain method for determination of residual stress in metallic materials" and is consistent with GB/T 24179-2009 In comparison, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) Change the term "calibration coefficient" to "strain function" (see Chapter 3, Chapter 3 of the 2009 edition);

b) Some symbols and descriptions have been changed (see Chapter 4, Chapter 4 of the 2009 edition);

c) Changed the principle description (see Chapter 5, Chapter 5 of the 2009 edition);

d) Delete the description of the piecewise linear relationship formula (2) and delete the formula (3) (see Chapter 5 of the 2009 edition);

e) The 60ohm strain gauge resistance value has been deleted (see 6.2.1 of the 2009 edition);

f) Changed the requirements for film base thickness (see 6.2.1, 2009 version of 6.2.1);

g) The upper limit of the indenter diameter has been changed (see 6.2.3, 6.4.1 of the 2009 edition);

h) The normative reference to GB/T 230.2 has been deleted (see 6.4.1 of the 2009 edition);

i) Added specific provisions on the stress relief process of heat treatment of calibration test plates (see 8.2.1);

j) It is clear that at least 7 to 8 stress levels are used for calibration to obtain a more accurate strain function, and the maximum value during calibration is increased.

The applied stress should be less than the elastic limit of the material rather than the yield limit (see 8.3.3, 8.2.3 of the 2009 edition);

k) Changed the calibration procedure for non-principal stress directions (see 8.5, 8.4 of the 2009 edition);

l) "Models of strain gauges, strain gauges, and indentation generating equipment used" are added to the test report (see Chapter 9, Chapter 9 of the 2009 edition).

1 Scope

This document specifies the basic principles, measuring equipment and materials, and measuring procedures for measuring residual stress on the surface of metallic materials using the indentation strain method. Steps, determination of stress calculation function and test report.

This document is applicable to the determination of residual stress on the surface of various metal materials with a hardness not greater than 50HRC.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 231.2 Brinell hardness test of metallic materials Part 2: Inspection and calibration of hardness tester

JJG 623 Calibration Regulations for Resistance Strain Gauges

3 Terms and definitions

The following terms and definitions apply to this document.

4 Symbols and descriptions

The symbols and descriptions used in this document are shown in Table 1.