Significance and Use
4.1 The Differential Indentation Depth hardness test is an empirical indentation hardness test that can provide useful information about metallic materials. This information can correlate to tensile strength, wear resistance, ductility, and other physical characteristics of metallic materials, and can be useful in quality control and selection of materials.
4.2 Differential Indentation Depth hardness tests are considered satisfactory for acceptance testing of commercial shipments, and have been used in industry for this purpose.
4.3 Differential Indentation Depth hardness testing at a specific location on a part might not represent the physical characteristics of the whole part or end product. Machines that comply with this Standard are used when machines that comply with the regular hardness standards such as Test Methods E10, E18, E92, and E384 cannot be used. Test results obtained with these machines are comparable BUT NOT EQUIVALENT to those obtained with machines that comply with the above mentioned standards.
4.4 Differential Indentation Depth hardness testing machines covered by this standard do not comply with Test Methods E10, E18, E92, or E110.
Scope
1.1 This test method covers the determination of the Differential Indentation Depth hardness of metallic materials by the Differential Indentation Depth hardness principle. This standard provides the requirements for Differential Indentation Depth hardness testing machines and the procedures for performing Differential Indentation Depth hardness tests.
1.2 This standard includes additional requirements in annexes:
| Verification of Differential Indentation Depth Hardness Testing Machines | Annex A1 |
| Guidelines for Determining the Minimum Thickness of a Test Piece | Annex A2 |
1.3 This standard includes non-mandatory information in appendixes which relates to the Differential Indentation Depth hardness test.
| List of ASTM Standards Giving Hardness Numbers Corresponding to Tensile Strength | Appendix X1 |
| Examples of Procedures for Determining Differential Indentation Depth Hardness Uncertainty | Appendix X2 |
| Examples of Indenters Used in Differential Indentation Depth Machines | Appendix X3 |
1.4 Units—This standard specifies the units of force and length in the International System of Units (SI); that is, force in Newtons (N) and length in micrometers (µm). However, because of continued common usage, values are provided in other units of measure for information.
1.5 The test principles, testing procedures, and verification procedures are essentially identical for all the Differential Indentation Depth hardness testing instruments. The testing instruments may use different test forces and indenter shapes. The type and size of the indenters are matched to the design of the instrument by the manufacturer. Accordingly, the indenters, probes and other instrument components are generally not interchangeable among manufacturers.
1.6 The hardness number reported by these instruments are based on direct correlations to existing hardness scales as determined by each manufacturer for each instrument and hardness scale. Unless otherwise noted on the instrument or in the operating manual for the instrument, the hardness numbers reported by the instrument are only applicable to non-austenitic steels. See 5.6.1 for additional information.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
