ASTM E92-2017 red 7500 Standard Test Methods for Vickers Hardness and Knoop Hardness of Metallic Materials《金属材料维氏硬度和努氏硬度的标准试验方法》.pdf

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1、Designation: E92 16E92 17Standard Test Methods forVickers Hardness and Knoop Hardness of MetallicMaterials1This standard is issued under the fixed designation E92; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last re

2、vision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope Scope*1.1 These test methods cover the determi

3、nation of the Vickers hardness and Knoop hardness of metallic materials by the Vickersand Knoop indentation hardness principles. This standard provides the requirements for Vickers and Knoop hardness machines andthe procedures for performing Vickers and Knoop hardness tests.1.2 This standard include

4、s additional requirements in annexes:Verification of Vickers and Knoop Hardness Testing Machines Annex A1Vickers and Knoop Hardness Standardizing Machines Annex A2Standardization of Vickers and Knoop Indenters Annex A3Standardization of Vickers and Knoop Hardness Test Blocks Annex A4Correction Facto

5、rs for Vickers Hardness Tests Made onSpherical and Cylindrical SurfacesAnnex A51.3 This standard includes nonmandatory information in an appendix which relates to the Vickers and Knoop hardness tests:Examples of Procedures for Determining Vickers andKnoop Hardness UncertaintyAppendix X11.4 This test

6、 method covers Vickers hardness tests made utilizing test forces ranging from 9.807 10-3 N to 1176.80 N (1 gfto 120 kgf), and Knoop hardness tests made utilizing test forces from 9.807 10-3 N to 19.613 N (1 gf to 2 kgf).1.5 Additional information on the procedures and guidance when testing in the mi

7、croindentation force range (forces 1 kgf)may be found in Test Method E384, Test Method for Microindentation Hardness of Materials.1.6 UnitsWhen the Vickers and Knoop hardness tests were developed, the force levels were specified in units of grams-force(gf) and kilograms-force (kgf). This standard sp

8、ecifies the units of force and length in the International System of Units (SI); thatis, force in Newtons (N) and length in mm or m. However, because of the historical precedent and continued common usage, forcevalues in gf and kgf units are provided for information and much of the discussion in thi

9、s standard as well as the method ofreporting the test results refers to these units.NOTE 1The Vickers and Knoop hardness numbers were originally defined in terms of the test force in kilogram-force (kgf) and the surface area orprojected area in millimetres squared (mm2). Today, the hardness numbers

10、are internationally defined in terms of SI units, that is, the test force in Newtons(N). However, in practice, the most commonly used force units are kilogram-force (kgf) and gram-force (gf). When Newton units of force are used, theforce must be divided by the conversion factor 9.80665 N/kgf.1.7 The

11、 test principles, testing procedures, and verification procedures are essentially identical for both the Vickers and Knoophardness tests. The significant differences between the two tests are the geometries of the respective indenters, the method ofcalculation of the hardness numbers, and that Vicke

12、rs hardness may be used at higher force levels than Knoop hardness.NOTE 2While Committee E28 is primarily concerned with metallic materials, the test procedures described are applicable to other materials. Othermaterials may require special considerations, for example see C1326 and C1327 for ceramic

13、 testing.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.1.9 This

14、 international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT

15、) Committee.1 These test methods are under the jurisdiction of ASTM Committee E28 on Mechanical Testing and is the direct responsibility of Subcommittee E28.06 on IndentationHardness Testing.Current edition approved Feb. 1, 2016April 1, 2017. Published April 2016May 2017. Originally approved in 1952

16、. Last previous edition approved in 20032016 asE9282(2003)E922 which was withdrawn July 2010 and reinstated in February 2016. DOI: 10.1520/E0092-16.16. DOI: 10.1520/E0092-17.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what chang

17、es have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the offici

18、al document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:2C1326 Test Method for Knoop Indentation Hardness of Advanced Ceram

19、icsC1327 Test Method for Vickers Indentation Hardness of Advanced CeramicsE3 Guide for Preparation of Metallographic SpecimensE6 Terminology Relating to Methods of Mechanical TestingE7 Terminology Relating to MetallographyE29 Practice for Using Significant Digits in Test Data to Determine Conformanc

20、e with SpecificationsE74 Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing MachinesE140 Hardness Conversion Tables for Metals Relationship Among Brinell Hardness, Vickers Hardness, Rockwell Hardness,Superficial Hardness, Knoop Hardness, Scleroscope

21、Hardness, and Leeb HardnessE175 Terminology of MicroscopyE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE384 Test Method for Microindentation Hardness of MaterialsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method2.2 ISO Stand

22、ards:3ISO 6507-1 Metallic MaterialsVickers hardness TestPart 1: Test MethodISO/IEC 17011 Conformity AssessmentGeneral Requirements for Accreditation Bodies Accrediting Conformity AssessmentBodiesISO/IEC 17025 General Requirements for the Competence of Testing and Calibration Laboratories3. Terminolo

23、gy and Equations3.1 Definitions of TermsFor the standard definitions of terms used in this test method, see Terminology E6 and TerminologyE7.3.1.1 indentation hardness, nthe hardness as evaluated from measurements of area or depth of the indentation made by forcinga specified indenter into the surfa

24、ce of a material under specified static loading conditions.3.1.2 Knoop hardness number, HK,nthe calculated result from a Knoop hardness test, which is proportional to the test forceapplied to the Knoop indenter divided by the projected area of the permanent indentation made by the indenter after rem

25、oval ofthe test force.3.1.2.1 DiscussionThe projected area of the permanent indentation made by the Knoop indenter is calculated based partly on the measured lengthof the long diagonal of the projected area of the indentation.3.1.3 Knoop hardness test, nan indentation test in which a Knoop rhombic-b

26、ased pyramidal diamond indenter havingspecified edge angles, is forced under specified conditions into the surface of the test material, and, after removal of the test force,the length of the long diagonal of the projected area of the indentation is measured to calculate the Knoop hardness number.3.

27、1.4 Vickers hardness number, HV,nthe calculated result from a Vickers hardness test, which is proportional to the test forceapplied to the Vickers indenter divided by the surface area of the permanent indentation made by the indenter after removal of thetest force.3.1.4.1 DiscussionThe surface area

28、of the permanent indentation made by the Vickers indenter is calculated based partly on the measured mean lengthof the two diagonals of the projected area of the indentation.3.1.5 Vickers hardness test, nan indentation test in which a Vickers square-based pyramidal diamond indenter having specifiedf

29、ace angles is forced under specified conditions into the surface of the test material, and, after removal of the test force, the lengthsof the two diagonals of the projected area of the indentation are measured to calculate the Vickers hardness number.3.2 Definitions of Terms Specific to This Standa

30、rd:3.2.1 standardization, nto bring in conformance to a known standard through verification or calibration.3.2.2 microindentation hardness test, na hardness test, normally in the Vickers or Knoop scales, using test forces in the rangeof 9.807 10-3 to 9.807 N (1 to 1000 gf).2 For referencedASTM stand

31、ards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floo

32、r, New York, NY 10036, http:/www.ansi.org.E92 1723.2.3 macroindention hardness test, na hardness test using test forces normally higher than 9.807 N (1 kgf). Macroindentationtests include Vickers, Rockwell and Brinell.NOTE 3Use of the term microhardness should be avoided because it implies that the

33、hardness, rather than the force or the indentation size, is verylow.3.2.4 scale, na specific combination of indenter (Knoop or Vickers) and the test force (kgf).3.2.4.1 DiscussionFor example, HV 10 is a scale defined as using a Vickers indenter and a 10 kgf test force and HK 0.1 is a scale defined a

34、s usinga Knoop indenter and a 100 gf test force. See 5.10 for the proper reporting of the hardness level and scale.3.2.5 as-found condition, nthe state of the hardness machine as reflected by the initial verification measurements made priorto performing any cleaning, maintenance, adjustments or repa

35、irs associated with an indirect verification.3.2.6 hardness machine, na machine capable of performing a Vickers or Knoop hardness test.3.2.7 hardness testing machine, na Vickers or Knoop hardness machine used for general testing purposes.3.2.8 hardness standardizing machine, na Vickers or Knoop hard

36、ness machine used for the standardization of Vickers orKnoop hardness test blocks.3.2.8.1 DiscussionA hardness standardizing machine differs from a hardness testing machine by having tighter tolerances on certain parameters.3.3 Equations:3.3.1 The average d of a set of n diagonal length measurements

37、 d1, d2, , dn is calculated as:d 5d11d211dnn (1)where each of the individual diagonal measurements d1, d2, , dn is the mean of the two diagonal length measurements in thecase of a Vickers indentation, or is the long diagonal length measurement in the case of a Knoop indentation.3.3.2 The repeatabili

38、ty R in the performance of aVickers or Knoop hardness machine at each hardness level, under the particularverification conditions, is determined from n diagonal measurements made on a standardized test block as part of a performanceverification. The repeatability is estimated as the percent range of

39、 n diagonal measurements with respect to the measured averagehardness value as:R 51003Sdmax2dmind D(2)where:dmax = the longest diagonal length measurement made on the standardized test block,dmin = the shortest diagonal length measurement made on the standardized test block, andd = the average (see

40、3.3.1) of the n diagonal length measurements made on the standardized test block.3.3.3 The error E in the performance of a Vickers or Knoop hardness machine at each hardness level, relative to a standardizedreference value, is calculated as a percent error determined as:E 51003Sd 2drefdref D (3)E 51

41、003S?d 2dref?dref D (3)where:d = the average (see 3.3.1) of n diagonal length measurements made on a standardized test block as part of a performanceverification, anddref = the certified diagonal length reported for the standardized test block.|d2dref|= absolute value (non-negative value without reg

42、ard to its sign) of the difference between d and dref.4. Significance and Use4.1 Vickers and Knoop hardness tests have been found to be very useful for materials evaluation, quality control ofmanufacturing processes and research and development efforts. Hardness, although empirical in nature, can be

43、 correlated to tensilestrength for many metals, and is an indicator of wear resistance and ductility.E92 1734.2 Microindentation hardness tests extend testing to materials that are too thin or too small for macroindentation hardness tests.Microindentation hardness tests also allow specific phases or

44、 constituents and regions or gradients too small for macroindentationhardness testing to be evaluated. Recommendations for microindentation testing can be found in Test Method E384.4.3 Because the Vickers and Knoop hardness will reveal hardness variations that may exist within a material, a single t

45、est valuemay not be representative of the bulk hardness.4.4 The Vickers indenter usually produces essentially the same hardness number at all test forces when testing homogeneousmaterial, except for tests using very low forces (below 25 gf) or for indentations with diagonals smaller than about 25 m

46、(see TestMethod E384). For isotropic materials, the two diagonals of a Vickers indentation are equal in length.4.5 The Knoop indenter usually produces similar hardness numbers over a wide range of test forces, but the numbers tend torise as the test force is decreased. This rise in hardness number w

47、ith lower test forces is often more significant when testing higherhardness materials, and is increasingly more significant when using test forces below 50 gf (see Test Method E384).4.6 The elongated four-sided rhombohedral shape of the Knoop indenter, where the length of the long diagonal is 7.114

48、timesgreater than the short diagonal, produces narrower and shallower indentations than the square-based pyramid Vickers indenterunder identical test conditions. Hence, the Knoop hardness test is very useful for evaluating hardness gradients since Knoopindentations can be made closer together than V

49、ickers indentations by orienting the Knoop indentations with the short diagonalsin the direction of the hardness gradient.5. Principle of Test and Apparatus5.1 Vickers and Knoop Hardness Test PrincipleThe general principle of the Vickers and Knoop indentation hardness testconsists of two steps.5.1.1 Step 1The applicable specified indenter is brought into contact with the test specimen in a direction normal to thesurface, and the test force F is applied. The test force is held for a specified dwell time and then removed.5.1.2 Ste