ASTM E384-2010e1 8750 Standard Test Method for Knoop and Vickers Hardness of Materials.pdf

1、Designation: E384 101Standard Test Method forKnoop and Vickers Hardness of Materials1This standard is issued under the fixed designation E384; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in p

2、arentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEThe title was editorially revised in March 2010.1. Scope*1.1 This test m

3、ethod covers determination of the Knoop andVickers hardness of materials, the verification of Knoop andVickers hardness testing machines, and the calibration ofstandardized Knoop and Vickers test blocks.1.2 This test method covers Knoop and Vickers hardnesstests made utilizing test forces in micro (

4、9.807 3 10-3to 9.807N)(1to1000 gf ) and macro (9.807 to 1176.68 N) ( 1kgto 120 kgf ) ranges.NOTE 1Previous versions of this standard limited test forces to 9.807N (1 kg).1.3 This test method includes all of the requirements toperform macro Vickers hardness tests as previously defined inTest Method E

5、92, Standard Test Method for Vickers HardnessTesting.1.4 This test method includes an analysis of the possiblesources of errors that can occur during Knoop and Vickerstesting and how these factors affect the accuracy, repeatability,and reproducibility of test results.NOTE 2While Committee E04 is pri

6、marily concerned with metals, thetest procedures described are applicable to other materials.1.5 UnitsWhen Knoop and Vickers hardness tests weredeveloped, the force levels were specified in units of grams (gf)and kilograms-force (kgf). This standard specifies the units offorce and length in the Inte

7、rnational System of Units (SI); thatis, force in Newtons (N) and length in mm or m. However,because of the historical precedent and continued commonusage, force values in gf and kgf units are provided forinformation and much of the discussion in this standard as wellas the method of reporting the te

8、st results refers to these units.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitat

9、ions prior to use.2. Referenced Documents2.1 ASTM Standards:2C1326 Test Method for Knoop Indentation Hardness ofAdvanced CeramicsC1327 Test Method for Vickers Indentation Hardness ofAdvanced CeramicsE3 Guide for Preparation of Metallographic SpecimensE7 Terminology Relating to MetallographyE29 Pract

10、ice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE74 Practice of Calibration of Force-Measuring Instru-ments for Verifying the Force Indication of Testing Ma-chinesE92 Test Method for Vickers Hardness of Metallic Materi-alsE122 Practice for Calculating Sample

11、Size to Estimate,With Specified Precision, the Average for a Characteristicof a Lot or ProcessE140 Hardness Conversion Tables for Metals RelationshipAmong Brinell Hardness, Vickers Hardness, RockwellHardness, Superficial Hardness, Knoop Hardness, andScleroscope HardnessE175 Terminology of Microscopy

12、E177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE766 Practice for Calibrating the Magnification of a Scan-ning Electron Microscope1This test method is under the jurisdiction of AS

13、TM Committee E04 onMetallography and is the direct responsibility of Subcommittee E04.05 on Micro-indentation Hardness Testing.With this revision the test method was expanded toinclude the requirements previously defined in E28.92, Standard Test Method forVickers Hardness Testing of Metallic Materia

14、l that was under the jurisdiction ofE28.06Current edition approved Feb. 1, 2010. Published February 2010. Originallyapproved in 1969. Last previous edition approved in 2009 as E384 09. DOI:10.1520/E0384-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer

15、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA

16、19428-2959, United States.2.2 ISO Standards:3ISO 6507-1 Metallic MaterialsVickers hardness TestPart 1: Test MethodISO/IEC 17011 Conformity AssessmentGeneral Require-ments for Accreditation Bodies Accrediting ConformityAssessment Bodies.ISO/IEC 17025 General Requirements for the Competenceof Testing

17、and Calibration Laboratories3. Terminology3.1 DefinitionsFor the standard definitions of terms usedin this test method, see Terminology E7.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibrating, vdetermining the values of the signifi-cant parameters by comparison with values indicated

18、by areference instrument or by a set of reference standards.3.2.2 Knoop hardness number, HK, nan expression ofhardness obtained by dividing the force applied to the Knoopindenter by the projected area of the permanent impressionmade by the indenter.3.2.3 Knoop indenter, na rhombic-based pyramidal-sh

19、aped diamond indenter with edge angles of /A = 172 308and / B = 130 08 (see Fig. 2).3.2.4 microindentation hardness test, na hardness testusing a calibrated machine to force a diamond indenter ofspecific geometry into the surface of the material beingevaluated, in which the test forces are 9.807 3 1

20、0-3to 9.807 N(1 to 1000 gf) and the indentation diagonal, or diagonals aremeasured with a light microscope after load removal; for anytest, it is assumed that the indentation does not undergo elasticrecovery after force removal. The test results are normally inthe Knoop or Vickers scales.3.2.5 macro

21、indention hardness test, na hardness test us-ing a calibrated machine to force an indenter of specificgeometry into the surface of the material being evaluated, inwhich the test forces are normally higher than 9.807 N (1 kgf).Macroindentation test scales include Vickers, Rockwell andBrinell.NOTE 3Us

22、e of the term microhardness should be avoided because itimplies that the hardness, rather than the force or the indentation size, isvery low.3.2.6 verifying, vchecking or testing the instrument toassure conformance with the specification.3.2.7 Vickers hardness number, HV, nan expression ofhardness o

23、btained by dividing the force applied to a Vickersindenter by the surface area of the permanent impression madeby the indenter.3.2.8 Vickers indenter, na square-based pyramidal-shapeddiamond indenter with face angles of 136 (see Fig. 1).3.2.9 scale, na specific combination of indenter (Knoopor Vicke

24、rs) and the test force. For example, HV10 is a scaledefined as using a Vickers indenter and a 10kg test force andHK0.1 is a scale defined as using a Knoop indenter and a 100gftest force. See 5.8 for the proper reporting of the hardness leveland scale.3.3 FormulaeThe formulae presented in 5.5 and 5.6

25、 forcalculating Knoop and Vickers hardness are based upon anideal tester. The measured value of the Knoop and Vickershardness of a material is subjected to several sources of errors.Based on Eq 1-9, variations in the applied force, geometricalvariations between diamond indenters, and human errors in

26、measuring indentation lengths can affect the calculated mate-rial hardness. The amount influence each of these parameters3Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.org.FIG. 1 Vickers I

27、ndenterE384 1012has on the calculated value of a Knoop or Vickers measurementis discussed in Section 10.4. Significance and Use4.1 Hardness tests have been found to be very useful formaterials evaluation, quality control of manufacturing pro-cesses and research and development efforts. Hardness, al-

28、though empirical in nature, can be correlated to tensile strengthfor many metals, and is an indicator of wear resistance andductility.4.2 Microindentation hardness tests extend testing to mate-rials that are too thin or too small for macroindentationhardness tests. Microindentation hardness tests al

29、so allowspecific phases or constituents and regions or gradients toosmall for macroindentation hardness testing to be evaluated.4.3 Because the Knoop and Vickers hardness will revealhardness variations that may exist within a material, a singletest value may not be representative of the bulk hardnes

30、s.4.4 The Vickers indenter usually produces a geometricallysimilar indentation at all test forces. Except for tests at verylow forces that produce indentations with diagonals smallerthan about 25 m, the hardness number will be essentially thesame as produced by Vickers machines with test forces grea

31、terthan 1 kgf, as long as the material being tested is reasonablyhomogeneous. For isotropic materials, the two diagonals of aVickers indentation are equal in size. Recommendations forlow force microindentation testing can be found in AppendixX5.4.5 The Knoop indenter does not produce a geometrically

32、similar indentation as a function of test force. Consequently,the Knoop hardness will vary with test force. Due to itsrhombic shape, the indentation depth is shallower for a Knoopindentation compared to a Vickers indentation under identicaltest conditions. The two diagonals of a Knoop indentation ar

33、emarkedly different. Ideally, the long diagonal is 7.114 timeslonger than the short diagonal, but this ratio is influenced byelastic recovery. Thus, the Knoop indenter is very useful forevaluating hardness gradients or thin coatings of sectionedsamples.5. Principle of Test5.1 In this test method, a

34、Knoop or Vickers hardness numberis determined based on the formation of a relatively smallindentation made in the test surface of samples being evalu-ated.5.2 A Knoop or Vickers indenter, made from diamond ofspecific geometry, is pressed into the test specimen surface byan accurately controlled appl

35、ied force using test machinesspecifically designed for such work.5.3 Knoop and Vickers hardness testing is divided intomicro and macro-test force ranges as defined:Range Test ForceMicro Micro 9.807 3 10-3 to # 9.807N(1to# 1000 gf)Macro Macro 9.807 to # 1176.68 N ( 1 to # 120 kgf)5.3.1 Knoop scale te

36、sting is normally performed usingmicro-range test forces (1kg and less) while the Vickers scaleis used over both the micro and macro-ranges.NOTE 4The user should consult with the manufacturer before apply-ing test forces in the macro-ranges (over 1 kg) with diamond indenterspreviously used for micro

37、-range testing. The diamond mount may not bestrong enough to support the higher test forces and the diamond may notbe large enough to produce the larger indent sizes.5.4 The size of the indentation is measured using a lightmicroscope equipped with a filar type eyepiece, or other typeof measuring dev

38、ice (see Terminology E175). Micro-rangeindents are typically measured in m (micrometers) andmacro-range indents are measured in mm. The formulas forboth units are given below.5.5 The Knoop hardness number is based upon the forcedivided by the projected area of the indentation5.5.1 For Knoop hardness

39、 testing, test loads are typically ingrams-force (gf) and indentation diagonals are in micrometersFIG. 2 Knoop IndenterE384 1013(m). The Knoop hardness number, in terms of gf and m, iscalculated using the following:HK 5 1.000 3 1033 P/Ap! 5 1.000 3 1033 P/cp3 d2! (1)orHK 5 14229 3 P/d2(2)Indenter co

40、nstant 5 cp5tan/B22 tan/A2(3)where:P = force, gf,d = length of long diagonal, m2,Ap= projected area of indentation,/A = included longitudinal edge angle, 172 30/B = included transverse edge angle, 130 0 (see Fig. 2and,cp= indenter constant relating projected area of the in-dentation to the square of

41、 the length of the longdiagonal, ideally 0.07028.NOTE 5HK values for a 1-gf (9.807 3 103N) test force arecontained inAppendix X6. To obtain HK values when other test forces areemployed, multiply the HK value from Table X6.1for the d value by theactual test force, g.5.5.2 The Knoop hardness, in terms

42、 of kgf and mm, isdetermined as follows:HK 5 14.229 3 P1/d12(4)where:P1= force, kgf, andd1= length of long diagonal, mm.5.5.3 The Knoop hardness reported with units of GPa isdetermined as follows:HK 5 0.014229 3 P2/d22(5)where:P2= force, N, andd2= length of the long diagonal of the indentation, mm.5

43、.6 The Vickers hardness number is based upon the forcedivided by the surface area of the indentation.5.6.1 For the micro-range Vickers hardness test loads aretypically in grams-force (gf) and indentation diagonals are inmicrometers (m). The Vickers hardness number, in terms of gfand m, is calculated

44、 as follows:HV 5 1.000 3 1033 P/As5 2.000 3 1033 P sin a/2!/d2(6)orHV 5 1854.4 3 P/d2(7)where:P = force, gf,As= surface area of the indentation, m2,d = mean diagonal length of the indentation, m, anda = face angle of the indenter, 136 0 (see Fig. 1).NOTE 6HV numbers for a 1-gf (9.807 3 103N) test lo

45、ad arecontained inAppendix X6. To obtain HV values when other test forces areemployed, multiply the HV value from Table X6.2 for the d value by theactual test force, g.5.6.2 Macro range Vickers hardness is typically determinedusing kgf and mm and is calculated as follows:HV 5 1.8544 3 P1/d12(8)where

46、:P1= force, kgf, andd1= mean diagonal length of the indentations, mm.5.6.3 The Vickers hardness reported with units of GPa isdetermined as follows:HV 5 0.0018544 3 P2/d22(9)where:P2= force, N, andd2= mean diagonal length of the indentations, mm.5.7 It is assumed that elastic recovery does not occur

47、whenthe indenter is removed after the loading cycle. That is, it isassumed that the indentation retains the shape of the indenterafter the force is removed. In Knoop testing, it is assumed thatthe ratio of the long diagonal to the short diagonal of theimpression is the same as for the indenter.5.8 T

48、he symbols HK for Knoop hardness, and HV forVickers hardness shall be used with the reported numericalvalues.5.8.1 For this standard, the hardness test results can bereported in several different ways. For example, if the Knoophardness was found to be 400, and the test force was 100 gf, thetest resu

49、lts may be reported as follows:5.8.1.1 In the kilogram force system: 400 HK 0.1.5.8.1.2 In the gram force system: 400 HK 100 gf.5.8.1.3 In the SI system: 3.92 GPa.5.8.1.4 For nonstandard dwell times, other than 10 to 15 s,the hardness would be reported as 400 HK 0.1 /22. In this case,22 would be the actual time of full load dwell time in seconds.5.9 The reported Knoop and Vickers hardness number shallbe reported rounded to three significant digits in accordancewith Practice E29 (for example, 725 HV 0.1, 99.2 HK 1).6. Apparatus6.1 T