ASTM_B_782_-_00.pdf

Designation:B 782 00Standard Specification forIron Graphite Sintered Bearings(Oil-Impregnated)1This standard is issued under the fixed designation B 782;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(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification covers iron-base sintered metal pow-der,oil-impregnated bearings.There are two grades,dependingon the level of combined carbon(see Table 1):1.1.1 Grade 1,Iron Graphitelow combined carbon and1.1.2 Grade 2,Iron Graphitehigh combined carbon.1.2 The values stated in inch-pound units are the standard.The metric equivalents of inch-pound units may be approxi-mate.NOTE1Definitions of powder metallurgy terms can be found inDefinitions B 243.Additional useful information is available in theRelated Material section of Vol 02.05 of the Annual Book of ASTMStandards.NOTE2Information on design,permissible loads,dimensional toler-ances,and recommended press fits and running clearances are provided inAppendix X1.2.Referenced Documents2.1 ASTM Standards:B 243 Terminology of Powder Metallurgy2B 328 Test Method for Density,Oil Content,and Intercon-nected Porosity of Sintered Powder Metal Structural Partsand Oil-Impregnated Bearings2E 9 Test Methods of Compression Testing of Metallic Ma-terials at Room Temperature3E 1019 Test Methods for Determination of Carbon,Sulfur,Nitrogen,and Oxygen in Steel and in Iron,Nickel,andCobalt Alloys43.Ordering Information3.1 Orders for material under this specification shall includethe following information:3.1.1 Grade(Table 1),3.1.2 Dimensions,and3.1.3 Certification(see Section 13).4.Materials and Manufacture4.1 Bearings shall be made by cold compacting and sinter-ing metal powders,with or without sizing,to produce finishedparts conforming to the requirements of this specification.5.Chemical Composition5.1 The material shall conform to the requirements pre-scribed in Table 1.6.Physical Properties6.1 DensityThe density of bearings supplied fully impreg-nated with lubricant shall be within the limits prescribed inTable 2.Density determinations shall be made in accordancewith Test Method B 328.6.2 Oil ContentOil content of bearings shall not be lessthan 18%for each grade when determined in accordance withTest Method B 328.7.Mechanical Properties7.1 Radial Crushing Force:7.1.1 Radial crushing force shall be determined by com-pressing the test specimen between two flat steel surfaces at a“no load speed no greater than 0.2 in./min(5 mm/min),thedirection of the load being normal to the longitudinal axis ofthe specimen.The point at which the load drops as a result ofthe first crack shall be considered the crushing strength.Thistest shall be applied to plain cylindrical bearings.Flangedbearings shall be tested by cutting off the flange and compress-ing the two sections separately.Each section shall meet theminimum strength requirements prescribed in Table 3.7.1.2 Radial crushing force shall not be less than the valuecalculated as follows:P 5 KLT2/D 2 T!(1)1This specification is under the jurisdiction of ASTM Committee B-9 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcommit-tee B09.04 on Bearings.Current edition approved October 10,2000.Published December 2000.Origi-nally published as B 782 88.Last previous edition B 782 94(1999).2Annual Book of ASTM Standards,Vol 02.05.3Annual Book of ASTM Standards,Vol 03.01.4Annual Book of ASTM Standards,Vol 03.06.TABLE 1 Chemical RequirementsElementComposition,%Grade 1Grade 2Iron,min94.594.5Graphite2.0 to 3.01.5 to 2.5Total other elements by difference,max2.02.0Combined carbon0 to 0.50.5 to 1.01Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 19428-2959,United States.where:P=radial crushing force,lbf(N);D=outside diameter of bearing,in.(mm);T=wall thickness of bearing,in.(mm);K=strength constant as shown in Table 3 for the gradespecified,psi(MPa(N/mm2);andL=length of bearings,in.(mm).7.1.3 Concerning spherical bearings,sample parts from a lotwill be machined to a straight wall and radially crushed tocalculate the K value.Sample parts from the same lot will beradially crushed as is(whole part).By correlation,the mini-mum radial crush value will be established on the wholebearing and so specified as the minimum radial crush value forthe part.8.Workmanship,Finish,and Appearance8.1 Bearings shall be uniform in composition.When cut orfractured,the exposed surface shall be of uniform appearance.9.Sampling9.1 LotUnless otherwise specified,a lot shall consist ofparts of the same form and dimensions made from powders ofthe same composition,formed and sintered under the sameconditions,and submitted for inspection at one time.9.2 Sample for Chemical AnalysisIf required,at least onesample for chemical analysis shall be taken from each lot.Arepresentative sample of c