Historical Version s - view previous versions of standard. More E Hardness, although empirical in nature, can be correlated to tensile strength for many metals, and is an indicator of wear resistance and ductility. Microindentation hardness tests also allow specific phases or constituents and regions or gradients too small for macroindentation hardness testing to be evaluated. Recommendations for microindentation testing can be found in Test Method E For isotropic materials, the two diagonals of a Vickers indentation are equal in length.
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A number in parentheses indicates the year of last reapproval. This standard has been approved for use by agencies of the U. Department of Defense.
Scope continued common usage, force values in gf and kgf units are 1. This refers to these units. NOTE 1—The Vickers and Knoop hardness numbers were originally standard provides the requirements for Vickers and Knoop defined in terms of the test force in kilogram-force kgf and the surface hardness machines and the procedures for performing Vickers area or projected area in millimetres squared mm2. Today, the hardness and Knoop hardness tests.
However, in practice, the most commonly used 1. The significant differences between the Spherical and Cylindrical Surfaces two tests are the geometries of the respective indenters, the 1.
Other materials may require special considerations, for example see 1. It is the responsibility of the user of this standard to establish appro- 1. Referenced Documents 1. Published April DOI: Determine the Precision of a Test Method 3. Part 1: Test Method 3. Terminology and Equations 3. See 5. Knoop rhombic-based pyramidal diamond indenter having 3. The repeatability is estimated as the E Principle of Test and Apparatus measurements made on the standardized test block. The test force is held for a specified dwell time and then removed.
However, 4. Significance and Use for the purposes of calculating the hardness results from the 4. In facturing processes and research and development efforts. Knoop testing, it is assumed that the ratio of the long diagonal Hardness, although empirical in nature, can be correlated to to the short diagonal of the indentation is the same as for the tensile strength for many metals, and is an indicator of wear indenter. Microindentation hardness tests also allow optical microscope to select the desired test location and to specific phases or constituents and regions or gradients too measure the size of the indentation produced by the test.
The small for macroindentation hardness testing to be evaluated. For isotropic materials, the two A3. This rise in hardness diamond. The diamond mount may not be strong enough to support the higher test forces and the diamond may F in kgf divided by the surface area AS of the indentation in not be large enough to produce the larger indentation sizes.
HV 5 5 4 are measured see 7. Additional guidance on measuring devices may be found in Test Method E To obtain the highest quality image for measuring the indentation diagonal, Other units of force and length may be used; however, the the measuring microscope should have adjustable illumination reported Vickers hardness number shall be converted to the intensity, adjustable alignment, aperture, and field diaphragms.
The magnifying objectives. Annex A1 prior to performing hardness tests. The accordance with Annex A1. Vickers hardness number, in terms of kgf and mm, is calculated 5. Test Piece where: 6. The quality of the tan 2 required surface finish can vary with the forces and magnifi- cP 5 5 0.
The lower the test force and the smaller the 2tan 2 indentation size, the more critical is the surface preparation. Knoop hardness number shall be converted to the units of kgf 6. The Knoop hardness heating or cold work. Re- HK 5 3 Etched surfaces can obscure the edge of test forces in kgf and the indentation long diagonal measured in the indentation, making an accurate measurement of the size of mm, is calculated as follows: the indentation difficult. This can readily be accomplished by surface grinding or otherwise Non-parallel test specimens can be tested 5.
The hardness numbers shall be followed by the in microindentation testing, it is necessary to mount the symbol HV for Vickers hardness, or HK for Knoop hardness, specimen for convenience in preparation and to maintain a and be supplemented by a value representing the test force in sharp edge when surface gradient tests are to be performed on kgf.
When mounting is required, the specimen 5. The thickness of the material under test should be The Knoop in- desired location on the test surface. Before applying the force, dentation depth hK is approximately make a final focus using the measuring objective see 7. For where the radius of curvature is in the direction of the short macroindentation testing, the contact velocity should not ex- diagonal. Annex A5 provides correction factors that shall be ceed 0. Test Procedure 7. The periodic verification should be test force for longer times.
In these instances the tolerance for performed on a daily basis. The application time shall be defined in the report. Because variations within this temperature 7. To minimize vibrations, the operator should avoid contacting the machine in any manner during the entire test 7. Focus 7. Avoid creating static charges during cleaning. Do not touch the tion manual for the proper procedure to produce alignment. Make another indentation and recheck the indentation location. Checks of the indenter 7. The objective selected to weights are changed.
The minimum surface is perpendicular to the indenter axis. Adjust the light intensity and adjust the diaphragms for optimum resolution and contrast. Check the specimen alignment as given in 7. This additional magnification block surface is perpendicular to the indenter axis as described does not change the optical resolution robj or the recommended diagonal lengths. Make an indentation. If the indentation is not symmetrical, the indenter is misaligned, and the tester shall not be used until it meets the requirements of sections 7.
The NA is frequently marked on the side of each perfectly aligned. Tests on single crystals or on textured objective. For indentations less result of being indented. In all cases, smaller measurement increments may be reported if the equipment is capable of 7. It is necessary to ensure that the spacing between indentations is large enough so that 7.
Check the specimen alignment as described in illustrated in Fig. Conversion to Other Hardness Scales or Tensile 3 Vickers and Knoop tests, six test forces in the micro Strength Values range, twenty-five laboratories, manual measurements, six 8.
See Test Method E Vickers or Knoop hardness numbers using one test force to 4 Vickers tests, four test forces in the macro range, seven hardness numbers using a different test force, or to other types laboratories, manual measurements, three different hardness of hardness numbers, or to tensile strength values. Such level test specimens. See Materials, conducted in Seven laboratories tested three Refer to E for hardness conversion tables for metals.
Only four laboratories were also brass, copper alloys, alloyed white cast irons, and wrought aluminum able to provide results at 50 kgf test force.
Each laboratory was asked to report triplicate 9. Report test results in order to permit the estimation of intralaboratory 9. Practice E was followed for the design and 9. RR: E The materials were described as the 9. Precision and Bias Tables
Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials
Standard Test Method for Vickers Hardness of Metallic Materials