1、Designation: B 925 08Standard Practices forProduction and Preparation of Powder Metallurgy (PM) TestSpecimens1This standard is issued under the fixed designation B 925; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of la
2、st 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 These standard practices cover the specifications forthose uniaxially compacted test specimens that are used inASTM sta
3、ndards, the procedures for producing and preparingthese test specimens, and reference the applicable standards.1.2 Basic tool design and engineering information regardingthe tooling that is required to compact the test specimens andmachining blanks are contained in the annexes.1.3 This standard is i
4、ntended to be a comprehensive one-source document that can be referenced byASTM test methodsthat utilize PM test specimens and in ASTM PM materialspecifications that contain the engineering data obtained fromthese test specimens.1.4 These practices are not applicable to metal powder testspecimens th
5、at are produced by other processes such as coldisostatic pressing (CIP), hot isostatic pressing (HIP), powderforging (PF) or metal injection molding (MIM). They do notpertain to cemented carbide materials.1.5 Detailed information on PM presses, compacting tool-ing and sintering furnaces, their desig
6、n, manufacture and useare not within the scope of these practices.1.6 Test specimen and die cavity dimensions shown ininch-pound units are to be regarded as standard and areapplicable to the referenced ASTM test methods and materialspecifications. Values in SI units are shown in parentheses andresul
7、t from conversion in accordance with IEEE/ASTM Stan-dard SI 10. They may be approximate and are only forinformation.1.7 This standard may involve hazardous materials, opera-tions, and equipment. This standard does not purport toaddress all of the safety concerns, if any, associated with itsuse. It i
8、s the responsibility of the user of this standard toestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 34/A 34M Practice for Sampling and Procurement Test-ing of Magnetic MaterialsA 34
9、1/A 341M Test Method for Direct Current MagneticProperties of Materials Using D-C Permeameters and theBallistic Test MethodsA 596/A 596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing SpecimensA 773/A 773M Test Method for dc Magnetic Properties ofMa
10、terials Using Ring and Permeameter Procedures withdc Electronic HysteresigraphsA811 Specification for Soft Magnetic Iron Parts Fabricatedby Powder Metallurgy (P/M) TechniquesA 839 Specification for Iron-Phosphorus Powder Metal-lurgy (P/M) Parts for Soft Magnetic ApplicationsA 904 Specification for 5
11、0 Nickel-50 Iron Powder Metal-lurgy (P/M) Soft Magnetic PartsA 927/A 927M Test Method for Alternating-Current Mag-netic Properties of Toroidal Core Specimens Using theVoltmeter-Ammeter-Wattmeter MethodB 215 Practices for Sampling Metal PowdersB 243 Terminology of Powder MetallurgyB 312 Test Method f
12、or Green Strength for CompactedMetal Powder SpecimensB 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated BearingsB 331 Test Method for Compressibility of Metal Powders inUniaxial CompactionB 438 Specification for Bronze-Base
13、Powder Metallurgy(PM) Bearings (Oil-Impregnated)B 439 Specification for Iron-Base Powder Metallurgy (PM)Bearings (Oil-Impregnated)1This practice is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base
14、Metal Powders.Current edition approved July 15, 2008. Published August 2008. Originallyapproved in 2003. Last previous edition approved in 2003 as B 92503.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
15、Standards 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 19428-2959, United States.B 528 Test Method for Tra
16、nsverse Rupture Strength ofMetal Powder SpecimensB 595 Specification for Sintered Aluminum Structural PartsB 610 Test Method for Measuring Dimensional Changes ofMetal Powder SpecimensB 715 Specification for Sintered Copper Structural Parts forElectrical Conductivity ApplicationsB 783 Specification f
17、or Materials for Ferrous Powder Met-allurgy (P/M) Structural PartsB 817 Specification for Powder Metallurgy (P/M) TitaniumAlloy Structural ComponentsB 823 Specification for Materials for Nonferrous PowderMetallurgy (P/M) Structural PartsB 853 Specification for Powder Metallurgy (PM) BoronStainless S
18、teel Structural ComponentsB 939 Test Method for Radial Crushing Strength, K,ofPowder Metallurgy (P/M) Bearings and Structural Materi-alsE8 Test Methods for Tension Testing of Metallic MaterialsE9 Test Methods of Compression Testing of Metallic Ma-terials at Room TemperatureE18 Test Methods for Rockw
19、ell Hardness of MetallicMaterialsE23 Test Methods for Notched Bar Impact Testing ofMetallic MaterialsE 228 Test Method for Linear Thermal Expansion of SolidMaterials With a Push-Rod DilatometerE 1876 Test Method for Dynamic Youngs Modulus, ShearModulus, and Poissons Ratio by Impulse Excitation ofVib
20、ration2.2 IEEE/ASTM Standard:SI 10 Standard for Use of the International System of Units(SI): The Modern Metric System22.3 MPIF Standard:Standard 56 Method for Determination of Rotating BeamFatigue Endurance Limit in Powder Metallurgy Materials33. Terminology3.1 DefinitionsDefinitions of powder meta
21、llurgy termscan be found in Terminology B 243. Additional descriptiveinformation is available in the Related Materials section of Vol02.05 of the Annual Book of ASTM Standards.4. Summary of Practice4.1 These practices describe the production, by pressing andsintering metal powders, and the preparati
22、on, by machiningsintered blanks, of test specimens used to measure properties ofmetal powders and sintered materials.5. Significance and Use5.1 Test specimens are used to determine the engineeringproperties of PM materials, for example, tensile strength,ductility, impact energy, etc.; property data
23、that are essential tothe successful use of PM material standards. Processing PMtest specimens under production conditions is the most efficientmethod by which to obtain reliable PM material property datasince in most cases it is impractical or impossible to cut testbars from sintered parts.5.2 The p
24、erformance characteristics of metal powders, forexample, compressibility, green strength and dimensionalchanges associated with processing are evaluated using PM testspecimens under controlled conditions. The data obtained areimportant to both metal powder producers and PM partsmanufacturers.5.3 PM
25、test specimens play a significant role in industrialquality assurance programs. They are used to compare prop-erties of a new lot of metal powder with an established lot inan acceptance test and are used in the part manufacturingprocess to establish and adjust production variables.5.4 In those insta
26、nces where it is required to presentequivalent property data for a production lot of PM parts,standard test specimens compacted from the production pow-der mix to the same green density can be processed with theproduction PM parts and then tested to obtain this information.5.5 Material property test
27、ing performed for industrial oracademic research and development projects uses standard PMtest specimens so the test results obtained can be comparedwith previous work or published data.5.6 Powder metallurgy test specimens may have multipleuses. The dimensions and tolerances given in this standard a
28、renominal in many cases. The user is cautioned to make certainthat the dimensions of the test specimen are in agreement withthe requirements of the specific test method to be used.6. Powder Metallurgy Test SpecimensPOWDER COMPRESSIBILITY TESTING6.1 Cylindrical Powder Compressibility Test Specimen:6.
29、1.1 Description and UseThis solid cylindrical testspecimen, see Fig. 1, is produced by compacting a test portionof powder mix in laboratory powder metallurgy tooling similarto that shown in Fig. A1.1 in the Annex. An alternative test3Available from MPIF, 105 College Road East, Princeton, NJ 08540.Di
30、mensionsin. mmDDiameter 1.00 25.4TCompact thickness 0.280 6 0.010 7.11 6 0.25FIG. 1 PM Cylindrical Powder Compressibility Test SpecimenB925082specimen for measuring powder compressibility is the trans-verse rupture test specimen. These test specimens are notsintered. The compressibility of the metal
31、 powder mix or acompressibility curve showing the green density as a functionof compacting pressure is determined according to the proce-dures in Test Method B 331.6.1.2 Applicable ASTM Standards:6.1.2.1 See Test Method B 331.TRANSVERSE RUPTURE, DIMENSIONAL CHANGEAND GREEN STRENGTH TESTING6.2 Transv
32、erse Rupture Strength Test Specimen:6.2.1 Description and UseThe pressed-to-size transverserupture test specimen, Fig. 2, is produced by compacting metalpowder in tooling similar to that shown in Fig A1.2.6.2.1.1 This rectangular test specimen has multiple uses inPM. Primarily, it is designed to det
33、ermine the transverserupture strength of sintered or heat treated compacts bybreaking the test specimen as a simple beam in three-pointloading following Test Method B 528. But, it is also used tomeasure the dimensional changes of metal powder mixes dueto pressing and sintering or other processing st
34、eps according toTest Method B 610, and it is used in both a 0.250 and 0.500 in.(6.35 and 12.70 mm) thick version to determine green strengthusing the procedure in Test Method B 312.6.2.1.2 It is an acceptable alternative test specimen to thecylindrical compact to determine powder compressibility ac-
35、cording to Test Method B 331. The sintered or heat treatedspecimen may be used to generate data for the elastic con-stants. Youngs Modulus is determined by impulse excitationof vibration and Poissons ratio may then be calculated. Thistest specimen is also a convenient compact on which tomeasure macr
36、oindentation hardness after various processingsteps.6.2.2 Applicable ASTM Standards:6.2.2.1 See the following Test Methods: B 312, B 331,B 528, B 610, E18, and E 1876.6.2.2.2 See the following PM Material Specifications:A811, A 839/A 839M, A 904, B 783, and B 823.RADIAL CRUSHING STRENGTH TESTING6.3
37、Radial Crushing Strength Test Specimen:6.3.1 Description and UseThe radial crushing strengthtest specimen shown in Fig. 3 is compacted to size in tooling(Fig. A2.3) suitable for the production of a thin-walled hollowcylinder within the range of the dimensions listed. The testingprocedure involves th
38、e application of a compressive forceperpendicular to the central axis of the test cylinder andcalculating the radial crushing strength from the breaking loadand test specimen dimensions. Radial crushing strength is thematerial property that is used to quantify the mechanicalstrength of sintered meta
39、l bearings, (oil-impregnated).6.3.1.1 Radial Crushing Strength is determined followingthe procedure in Test Method B 939.6.3.1.2 This test specimen is widely used in a quality controltest to determine the sintered material strength of metal powdermixtures that are to be used for the production of an
40、y metalpowder product because it is a quick, easy test and givesreliable and reproducible results. Laboratories testing powdermixes intended for the manufacture of porous bearings haverecognized that breaking an unsintered test specimen bydiametrical loading will give a green strength value that isr
41、elevant in production.6.3.2 Applicable ASTM Standards:Dimensionsin. mmWWidth 0.50 12.7LLength 1.25 31.8RCorner radius 0.01 0.3TThickness (thin) 0.250 6 0.005 6.35 6 0.13TThickness (thick) 0.500 6 0.005 12.70 6 0.13NOTEThickness shall be parallel within 0.005 in. (0.13 mm).FIG. 2 PM Transverse Ruptur
42、e Strength Test SpecimenDimensionsin. mmDOutside diameter 0.80 to 2.00 20 to 51dInside diameter 0.50 to 1.00 13 to 25TThickness 0.25 to 1.00 6 to 25NOTEWall thickness (D-d) shall be less than D/3.FIG. 3 PM Radial Crushing Strength Test SpecimenB9250836.3.2.1 See Test Method B 939.6.3.2.2 See the fol
43、lowing PM Bearing Specifications: B 438and B 439.TENSION TESTING6.4 Flat Unmachined Tension Test Specimen:6.4.1 Description and UseThe unmachined flat tensiontest specimen shown in Fig. 4 is commonly referred to in theindustry as “the dogbone.” It is compacted directly to size andshape using tooling
44、 similar to that shown in Fig. A2.4 in theAnnex. This test specimen has been designed to have aconvenient 1.00 in.2(645.2 mm2) pressing area to simplifycompacting calculations.6.4.1.1 It is intended for determining the tensile propertiesand ductility of PM materials that have not been heat treated(n
45、ot quenched and tempered nor sinter-hardened). The testingprocedures for this unmachined PM test specimen can be foundin Test Method E8.6.4.1.2 The flat tension test specimen is not normally usedwith heat treated PM materials because it may produceunreliable test results and it has a tendency to sli
46、p in the grips.Slippage can be prevented by the use of hydraulic grips, but thesquare corner design of the flat specimen will give rise to stressconcentrations that may result in scattered test values. Themachined 190-Round tension test specimen, Fig. 5, is recom-mended for use with heat treated PM
47、materials.6.4.2 Applicable ASTM Standards:6.4.2.1 See Test Methods E8.6.4.2.2 See the following PM Material Specifications:A811, A 839/A 839M, A 904, B 715, B 783, B 823, andB 853.6.5 Machined 190-Round Tension Test Specimen:6.5.1 Description and UseThe 190-Round tension testspecimen may be prepared
48、 by machining a sintered Izod testspecimen blank, to the shape and dimensions shown in Fig. 5.The gage section shall be free of nicks, scratches, tool marks orother conditions that can deleteriously affect the properties tobe measured. It is primarily used to measure the tensileproperties and ductil
49、ity of heat treated (quenched and temperedor sinter-hardened) PM materials because it gives more con-sistent test data than those obtained with the flat unmachinedtension test specimen, Fig. 4. These tension properties aredetermined following the testing procedures detailed in TestMethod E8.6.5.2 Applicable ASTM Standards:6.5.2.1 See Test Methods E8.6.5.2.2 See the following PM Material Specifications:B 595, B 783, and B 817.COMPRESSION TESTING6.6 Machined Compression Test Specimen:6.6.1 Description and UseThis test specimen, shown inFig. 6, is usually prepared
