GB/T 18449.1-2024Metallic materials - Knoop hardness test - Part 1: Test method (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting:

This document is part 1 of GB/T 18449 Knoop hardness test for metallic materials: GB/T 18449 has been published as follows part:

--- Part 1: Test methods;

--- Part 2: Verification and calibration of hardness testers;

--- Part 3: Calibration of standard hardness blocks;

--- Part 4: Hardness value table:

This document replaces GB/T 18449.1-2009 "Metallic materials Knoop hardness test Part 1: Test method" and partially replaces GB/T 9790-2021 "Vickers and Knoop microhardness test for metal and other inorganic coatings of metallic materials":

GB/T 18449.1-2009 is the main version, and part of GB/T 9790-2021 is integrated:

In addition to structural adjustments and editorial changes, the main technical changes are as follows:

--- Changed the scope, added that this document also applies to metals and other inorganic coatings, and extended the lower limit of the Knoop hardness test force to 0:009807N (see Chapter 1, Chapter 1 of GB/T 18449.1-2009);

--- Added the resolution requirements of the indentation measurement system corresponding to different diagonal length measurement ranges (see Table 2);

--- The increased specimen thickness or test layer thickness should be at least 1/3 of the diagonal length of the indentation (see 7.3);

--- Added the determination of Knoop hardness of metal and other inorganic coatings (see 7.5);

--- Added typical test forces HK0.001, HK0.002 and HK0.005 (see Table 3);

--- Increased period verification (see 8.3);

--- Changed the target values of force application time and holding time under maximum force (see 8.6, Chapter 7 of GB/T 18449.1-2009);

--- Added the minimum distance between adjacent indentations and the minimum distance between any indentation and the edge of the specimen (see Figure 3);

--- Added requirements for hardness conversion method (see Chapter 10);

--- Added the normative appendix "Determination of Knoop hardness of metals and other inorganic coatings" (see Appendix A);

--- Changed Appendix B to a normative appendix, added the period inspection content of the diagonal length measurement system and the pressure head, and added the table B:1HK maximum allowable deviation value and added pressure head inspection (see Appendix B, Appendix A of GB/T 18449.1-2009):

This document is modified to adopt ISO 4545-1:2023 "Knoop hardness test for metallic materials - Part 1: Test method":

The technical differences between this document and ISO 4545-1:2023 and their reasons are as follows:

--- Replaced ISO 4545-2:2017 (see Chapter 6, Appendix B) with the normative reference GB/T 18449.2 to adapt to my country's technical requirements:

Technical conditions and increase operability;

--- ISO 4545-3 (see Appendix B) has been replaced by the normative reference GB/T 18449.3 to adapt to my country's technical conditions and increase Operability;

--- Added normative reference to JJG1047 (see 6.1) to adapt to my country's technical conditions and increase operability:

The following editorial changes were made to this document:

--- Replaced ISO 14577-1 with the informative reference GB/T 21838.1 (see Chapter 1, 8:9);

--- Replaced ISO 14577-2 with the informative reference GB/T 21838.2 (see 8.9);

--- Replaced ISO 14577-3 with the informative reference GB/T 21838.3 (see 8.9);

--- Replaced ISO 4545-4 with the informative reference GB/T 18449.4 (see 8.10);

--- Added the informative reference to JJF1059.1 (see Chapter 9);

--- ISO 1463 is replaced by the informative reference GB/T 6462 (see Appendix A);

--- Replaced ISO 14577-4 with the informative reference GB/T 21838.4 (see Appendix A);

--- Corrected the reference errors of international standards (see Appendix D):

Introduction

GB/T 18449 "Knoop hardness test for metallic materials" is intended to standardize the Knoop hardness test method for metallic materials, the inspection and calibration of hardness testers:

The calibration and hardness value of standard hardness blocks, etc:

GB/T 18449 consists of 4 parts:

--- Part 1: Test methods;

--- Part 2: Verification and calibration of hardness testers;

--- Part 3: Calibration of standard hardness blocks;

--- Part 4: Hardness value table:

This document provides the test method for Knoop hardness:

Knoop hardness test for metal materials Part 1: Test methods

1 Scope

This document specifies the principle, hardness tester, specimen, test procedure, uncertainty of results and test report for the Knoop hardness test of metals:

This document specifies the Knoop hardness test with a test force range of 0:009807N~19:613N:

This document specifies the Knoop hardness test with an indentation diagonal length of not less than 0:020 mm:

Imperfections in the indenter geometry lead to large uncertainties and the use of this method to determine the Knoop hardness from smaller indentations is beyond the scope of this document:

The results will be within a certain range because of the great uncertainty:

This document also specifies the periodic inspection method for users to perform daily inspections on hardness testers:

The Knoop hardness test specified in this document is also applicable to metallic and other inorganic coatings, including electrophoretic coatings on aluminum substrates, self-catalyzed coatings, Chemical coating, spray coating and anodic coating:

This document applies to indentation measurements perpendicular to the surface of the coating and to cross-sectional measurements, provided that the characteristics of the coating (smoothness, thickness etc:) allows accurate reading of the diagonal of the indentation:

This document is not applicable to coatings with a thickness less than 0:007 mm when tested perpendicular to the surface of the covering layer and to coatings with a cross-section thickness less than 0:007 mm when tested perpendicular to the surface of the covering layer:

For coatings with a thickness of less than 0:020 mm, GB/T 21838.1 can be used to determine the hardness of smaller indentations:

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document:

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document:

GB/T 18449.2 Knoop hardness test for metallic materials Part 2: Verification and calibration of hardness testers (GB/T 18449.2-2012,ISO 4545-2:2005,MOD) GB/T 18449.3 Knoop hardness test for metallic materials Part 3: Calibration of standard hardness blocks (GB/T 18449.3-2012,ISO 4545-3:2005,MOD) JJG1047 Verification Procedure for Metal Knoop Hardness Tester

3 Terms and definitions

There are no terms or definitions that require definition in this document:

4 Symbols and instructions

4.1 Symbols and instructions used in this document Symbols and descriptions are shown in Table 1: