1、Designation: B 925 03Standard Practices forProduction and Preparation of Powder Metallurgy (P/M) 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 l
2、ast 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 These standard practices cover the specifications forthose uniaxially compacted test specimens that are used inASTM st
3、andards, 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
4、intended to be a comprehensive one-source document that can be referenced by ASTM test methodsthat utilize P/M test specimens and in ASTM P/M materialspecifications that contain the engineering data obtained fromthese test specimens.1.4 These practices are not applicable to metal powder testspecimen
5、s that are produced by other processes such as coldisostatic pressing (CIP), hot isostatic pressing (HIP), powderforging (P/F) or metal injection molding (MIM). They do notpertain to cemented carbide materials.1.5 Detailed information on P/M presses, compacting tool-ing and sintering furnaces, their
6、 design, 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 an
7、dresult 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
8、. It is 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:A 34/A 34M Practice for Sampling and Procurement Test-ing of Magnetic Material
9、s2A 341/A 341M Test Method for Direct-Current MagneticProperties of Materials Using D-C Permeameters and theBallistic Test Methods2A 596/A 596M Test Method for Direct-Current MagneticProperties of Materials Using the Ballistic Method andRing Specimens2A 773/A 773M Test Method for dc Magnetic Propert
10、ies ofMaterials Using Ring and Permeameter Procedures withElectronic Hysteresigraphs2A 811 Specification for Soft Magnetic Iron Parts Fabricatedby Powder Metallurgy (P/M) Techniques2A 839/A 839M Specification for Iron Phosphorus PowderMetallurgy (P/M) Parts for Soft Magnetic Applications2A 904 Speci
11、fication for 50 Nickel-50 Iron Powder Metal-lurgy (P/M) Soft Magnetic Alloys2A 927/A 927M Test Method for Alternating-Current Mag-netic Properties of Torroidal Core Specimens Using theVoltmeter-Ammeter-Wattmeter Method2B 215 Practices for Sampling Finished Lots of Metal Pow-der3B 243 Terminology of
12、Powder Metallurgy3B 312 Test Method for Green Strength for CompactedMetal Powder Specimens3B 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impregnated Bearings3B 331 Test Method for Compressibility of Metal Powders inUniaxial Compact
13、ion3B 438/B 438M Specification for Sintered Bronze Bearings(Oil-Impregnated)3B 439 Specification for Iron-Base Sintered Bearings (Oil-Impregnated)3B 528 Test Method for Transverse Rupture Strength ofMetal Powder Specimens3B 595 Specification for Sintered Aluminum StructuralParts3B 610 Test Method fo
14、r Measuring Dimensional Changes of1This 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 Metal Powders.Current edition approved April 10, 2003. Published June 2003.2Annual Book of ASTM
15、Standards, Vol 03.04.3Annual Book of ASTM Standards, Vol 02.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Metal Powder Specimens3B 612 Specification for Iron Bronze Sintered Bearings (Oil-Impregnated)3B 715 Specification for Sin
16、tered Copper Structural Parts forElectrical Conductivity Applications3B 782 Specification for Iron Graphite Sintered Bearings(Oil-Impregnated)3B 783 Specification for Materials for Ferrous Powder Met-allurgy (P/M) Structural Parts3B 817 Specification for Powder Metallurgy (P/M) TitaniumAlloy Structu
17、ral Components3B 823 Specification for Materials for Nonferrous PowderMetallurgy (P/M) Structural Parts3B 853 Specification for Powder Metallurgy (P/M) BoronStainless Steel Structural Components3E 8 Test Methods for Tension Testing of Metallic Materials4E 9 Test Methods of Compression Testing of Met
18、allic Ma-terials at Room Temperature4E 18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic Materials4E 23 Test Methods for Notched Bar Impact Testing ofMetallic Materials4E 228 Test Method for Linear Thermal Expansion of SolidMaterials with a Vitreous Silica Dilatomete
19、r2E 1876 Test Method for Dynamic Youngs Modulus, ShearModulus and Poissons Ratio by Impulse Excitation ofVibration42.2 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 BeamF
20、atigue Endurance Limit in Powder Metallurgy Materials53. Terminology3.1 DefinitionsDefinitions of powder metallurgy 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 P
21、ractice4.1 These practices describe the production, by pressing andsintering metal powders, and the preparation, 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 engine
22、eringproperties of P/M materials, for example, tensile strength,ductility, impact energy, etc.; property data that are essential tothe successful use of P/M material standards. Processing P/Mtest specimens under production conditions is the most efficientmethod by which to obtain reliable P/M materi
23、al property datasince in most cases it is impractical or impossible to cut testbars from sintered parts.5.2 The performance characteristics of metal powders, forexample, compressibility, green strength and dimensionalchanges associated with processing are evaluated using P/Mtest specimens under cont
24、rolled conditions. The data obtainedare important to both metal powder producers and P/M partsmanufacturers.5.3 P/M 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 acceptanc
25、e test and are used in the part manufacturingprocess to establish and adjust production variables.5.4 In those instances where it is required to presentequivalent property data for a production lot of P/M parts,standard test specimens compacted from the production pow-der mix to the same green densi
26、ty can be processed with theproduction P/M parts and then tested to obtain this information.5.5 Material property testing performed for industrial oracademic research and development projects uses standardP/M test specimens so the test results obtained can be com-pared with previous work or publishe
27、d data.5.6 Powder metallurgy test specimens may have multipleuses. The dimensions and tolerances given in this standard arenominal 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
28、.6. Powder Metallurgy Test SpecimensPOWDER COMPRESSIBILITY TESTING6.1 Cylindrical Powder Compressibility Test Specimen:6.1.1 Description and UseThis solid cylindrical testspecimen, see Fig. 1, is produced by compacting a test portionof powder mix in laboratory powder metallurgy tooling similarto tha
29、t shown in Fig. A1.1 in the Annex. An alternative testspecimen for measuring powder compressibility is the trans-verse rupture test specimen. These test specimens are not4Annual Book of ASTM Standards, Vol 03.01.5Available from MPIF, 105 College Road East, Princeton, NJ 08540.Dimensionsin. mmDDiamet
30、er 1.00 25.4TCompact thickness 0.280 6 0.010 7.11 6 0.25FIG. 1 P/M Cylindrical Powder Compressibility Test SpecimenB925032sintered. The compressibility of the metal powder mix or acompressibility curve showing the green density as a functionof compacting pressure is determined according to the proce
31、-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 Transverse Rupture Strength Test Specimen:6.2.1 Description and UseThe pressed-to-size transverserupture test specimen, Fig. 2, is produced by
32、 compacting metalpowder in tooling similar to that shown in Fig A1.2.6.2.1.1 This rectangular test specimen has multiple uses inP/M. Primarily, it is designed to determine the transverserupture strength of sintered or heat treated compacts bybreaking the test specimen as a simple beam in three-point
33、loading 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 steps 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 str
34、engthusing 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-cording to Test Method B 331. The sintered or heat treatedspecimen may be used to generate data for the elastic con-stants. Youngs Modu
35、lus is determined by impulse excitationof vibration and Poissons ratio may then be calculated. Thistest specimen is also a convenient compact on which tomeasure macroindentation hardness after various processingsteps.6.2.2 Applicable ASTM Standards:6.2.2.1 See the following Test Methods: B 312, B 33
36、1,B 528, B 610, E 18, and E 1876.6.2.2.2 See the following P/M Material Specifications:A 811, A 839/A 839M, A 904, B 783, and B 823.RADIAL CRUSHING TESTING6.3 Radial Crushing Strength Test Specimen:6.3.1 Description and UseThe radial crushing strengthtest specimen shown in Fig. 3 is compacted to siz
37、e in tooling(Fig. A2.3) suitable for the production of a thin-walled hollowcylinder within the range of the dimensions listed. The testingprocedure involves the application of a compressive forceperpendicular to the central axis of the test cylinder andcalculating the radial crushing strength from t
38、he breaking loadand test specimen dimensions. Radial crushing strength is thematerial property that is used to quantify the mechanicalstrength of sintered metal bearings, (oil impregnated).6.3.1.1 This test specimen is widely used in a quality controltest to determine the sintered material strength
39、of powdermixes that are to be used for the production of any 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 bydi
40、ametrical loading will give a green strength value that isrelevant in production.6.3.2 Applicable ASTM Standards:6.3.2.1 See the following P/M Bearing Specifications:B 438/B 438M, B 439, B 612, and B 782.Dimensionsin. mmWWidth 0.50 12.7LLength 1.25 31.8RCorner radius 0.01 0.3TThickness (thin) 0.250
41、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 P/M Transverse Rupture 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 25N
42、OTEWall thickness (D-d) shall be less than D/3.FIG. 3 P/M Radial Crushing Strength Test SpecimenB925033TENSION 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.” I
43、t is compacted directly to size andshape using tooling 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 ducti
44、lity of P/M materials that have not been heat treated(not quenched and tempered nor sinter-hardened). The testingprocedures for this unmachined P/M test specimen can befound in Test Method E 8.6.4.1.2 The flat tension test specimen is not normally usedwith heat treated P/M materials because it may p
45、roduceunreliable test results and it has a tendency to slip 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 speci
46、men, Fig. 5, is recom-mended for use with heat treated P/M materials.6.4.2 Applicable ASTM Standards:6.4.2.1 See Test Methods E 8.6.4.2.2 See the following P/M Material Specifications:A 811, 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 Descrip
47、tion and UseThe 190-Round tension testspecimen may be prepared 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
48、 is primarily used to measure the tensileproperties and ductility of heat treated (quenched and temperedor sinter-hardened) P/M materials because it gives moreconsistent test data than those obtained with the flat unma-chined tension test specimen, Fig. 4. These tension propertiesare determined foll
49、owing the testing procedures detailed inTest Method E 8.6.5.2 Applicable ASTM Standards:6.5.2.1 See Test Methods E 8.6.5.2.2 See the following P/M 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 by machining a sintered Izod testspecimen blank. It can also be prepared from large, 1.005 in.(26.7 mm) thick sintered blanks which are sawed verticallyinto smaller pieces for turning into test specimens that are to betested in the compa
