ASTM_B_294_-_17.pdf

Designation:B29417Standard Test Method forHardness Testing of Cemented Carbides1This standard is issued under the fixed designation B294;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 parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers the hardness testing of ce-mented carbides by use of a Rockwell hardness tester perform-ing tests in the Rockwell HRA scale(regular scale,diamondindenter,10 kgf(98.07 N)preliminary test force,and 60 kgf(588.4 N)total test force in the range of Rockwell 80 HRAandabove.Also covered are the procedures for the testing andselection of diamond indenters,the management and traceabil-ity of the four levels of standardized test blocks,and themaking and calibration of Primary,Secondary,and Workingstandardized test blocks.1.2 The Rockwell hardness tester is a convenient andreliable means of measuring the hardness of cemented car-bides.A hardness value is obtained easily,but it is subject toconsiderable error unless certain precautions are observed.1.3 The latest version of Test Methods E18 shall be fol-lowed except where otherwise indicated in this test method.1.4 The values stated in SI units are to be regarded asstandard except that force and length values associated with theRockwell hardness testers will comply with E18 with forcevalues specified as N(kgf)and indenter length values specifiedas mm.1.5 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2E18 Test Methods for Rockwell Hardness of Metallic Ma-terialsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with Specifications2.2 ISO Standards:3ISO/IEC 17011 Conformity AssessmentGeneral Require-ments for Accreditation Bodies Accrediting ConformityAssessment BodiesISO/IEC 17025 General Requirements for the Competenceof Testing and Calibration Laboratories3.Significance and Use3.1 Rockwell hardness testing is one of the more importantmethods used to evaluate cemented carbides.For composi-tional groups of cemented carbides,hardness is an indication ofwear resistance and toughness.Lower hardness grades usuallyindicate less wear resistance but greater toughness.For aspecific grade of cemented carbide,hardness is an indication ofthe metallurgical quality of the material.In no case is Rockwellhardness testing the only test method to be considered inevaluating cemented carbides.4.Principles of Test Apparatus4.1 TesterAll hardness tests shall be performed using aRockwell hardness tester that meets the requirements definedin the latest version of Test Method E18 except whereotherwise indicated in this test method.Testers shall complywith the requirements of Annex A3 of this test method.4.2 ScaleAll tests shall be performed using the carbideRockwell HRA scale(a carbide diamond indenter,10 kgf(98.07 N)preliminary force,and 60 kgf(588.4 N)total testforce.4.3 Effect of VibrationThe Rockwell hardness testershould be located in a vibration-free area in order to avoid1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.06 on Cemented Carbides.Current edition approved Nov.1,2017.Published February 2018.Originallyapproved in 1954.Last previous edition approved in 2010 as B294 10.DOI:10.1520/B0294-17.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*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 StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 erroneous results.If this is not possible,the tester shall bemounted so