1、Designation:B93915Standard Test Method forRadial Crushing Strength,K,of Powder Metallurgy(PM)Bearings and Structural Materials1This standard is issued under the fixed designation B939;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,t
2、he 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 equipment and laboratoryprocedure for the determination of the radial crushing stre
3、ngthof materials using either a plain powder metallurgy(PM)bearing or a thin-walled hollow cylindrical test specimen.Thisis a destructive test that produces quantitative results.1.2 Limitations:1.2.1 The principle of this procedure is based on thematerial being tested having minimal ductility.The pe
4、rmanentdeflection of the cylinder during the test should not exceed10%of the outside diameter.1.2.2 The radial crushing strength test results should be usedonly as a guide if the test specimen has a wall thickness that isgreater than one-third of the outside diameter.These test resultsshould then on
5、ly be used for comparison with data from the testspecimens of like materials and similar dimensions.1.3 With the exception of the values for density and themass used to determine density,for which the use of the gramper cubic centimetre(g/cm3)and gram(g)units are theindustry standard,the values stat
6、ed in inch-pound units are tobe regarded as standard.The values given in parentheses aremathematical conversions to SI units that are provided forinformation only and are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It
7、 is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B243 Terminology of Powder MetallurgyB438 Specification for Bronze-Base Powder Me
8、tallurgy(PM)Bearings(Oil-Impregnated)B439 Specification for Iron-Base Powder Metallurgy(PM)Bearings(Oil-Impregnated)B925 Practices for Production and Preparation of PowderMetallurgy(PM)Test SpecimensE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory St
9、udy toDetermine the Precision of a Test Method2.2 MPIF Standard:3MPIF Standard 55 Determination of Radial Crush Strength(K)of Powder Metallurgy(PM)Test Specimens3.Terminology3.1 DefinitionsDefinitions of powder metallurgy(PM)terms can be found in Terminology B243.Additional descrip-tive information
10、is available in the related material section ofVol 02.05 of the Annual Book of ASTM Standards.4.Summary of Test Method4.1 Radial crushing strength is determined by subjecting aplain sleeve bearing or a thin-walled cylindrical test specimento a controlled compressive force applied perpendicular to it
11、scentral axis under uniformly increasing load until fractureoccurs.4.2 The term“radial crushing strength,”as used in this testmethod is the stress at fracture calculated from the breakingload and the dimensions of the test specimen.5.Significance and Use5.1 The radial crushing strength test is a des
12、tructive proce-dure used to determine a material strength characteristic of PMbearings and hollow cylindrical test specimens.These data canbe used to grade,classify,and evaluate the materials.5.2 The PM bearing Specifications B438 and B439 requirethe use of this test method as an acceptance test for
13、 the strengthof oil-impregnated sintered bearings.1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.04 on Bearings.Current edition approved April 1,2015.Published April 2015.Originallyappr
14、oved in 2005.Last previous edition approved in 2009 as B939 09.DOI:10.1520/B0939-15.2For 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 o
15、nthe ASTM website.3Available from Metal Powder Industries Federation(MPIF),105 College Rd.East,Princeton,NJ 08540,http:/www.mpif.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
16、States1 5.3 This test method may be used by powder producers andparts manufacturers as a lot acceptance test for metal powdersand lubricated powder mixtures intended for the production ofporous parts.5.4 Companies in the PM industry use this test as amanufacturing control test because it is appropriate for pro-duction practices.5.5 Radial crushing strength is a property of the PMmaterial but is not a design value.However,experience hasshown that the radial crushing strength of a material isappro