1、Designation: B925 08B925 15Standard Practices forProduction and Preparation of Powder Metallurgy (PM) TestSpecimens1This standard is issued under the fixed designation B925; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year
2、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 These standard practices cover the specifications for those uniaxially compacted test specimens that are used in A
3、STMstandards, the procedures for producing and preparing these test specimens, and reference the applicable standards.1.2 Basic tool design and engineering information regarding the tooling that is required to compact the test specimens andmachining blanks are contained in the annexes.1.3 This stand
4、ard is intended to be a comprehensive one-source document that can be referenced by ASTM test methods thatutilize PM test specimens and in ASTM PM material specifications that contain the engineering data obtained from these testspecimens.1.4 These practices are not applicable to metal powder test s
5、pecimens that are produced by other processes such as cold isostaticpressing (CIP), hot isostatic pressing (HIP), powder forging (PF) or metal injection molding (MIM). They do not pertain tocemented carbide materials.1.5 Detailed information on PM presses, compacting tooling and sintering furnaces,
6、their design, manufacture and use are notwithin the scope of these practices.1.6 Test specimen and die cavity dimensions shown The values stated in inch-pound units are to be regarded as standard andare applicable to the referenced ASTM test methods and material specifications. Values in SI units ar
7、e shown in parentheses andresult from conversion in accordance with IEEE/ASTM Standard SI 10. They may be approximate and are only forinformation.standard. The values given in parentheses are mathematical conversions to SI units that are provided for informationonly and are not considered standard.1
8、.7 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address allof the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriatesafety and health practices and determine t
9、he applicability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A34/A34M Practice for Sampling and Procurement Testing of Magnetic MaterialsA341/A341M Test Method for Direct Current Magnetic Properties of Materials Using D-C Permeameters and the Ballistic TestMetho
10、dsA596/A596M Test Method for Direct-Current Magnetic Properties of Materials Using the Ballistic Method and Ring SpecimensA773/A773M Test Method for Direct Current Magnetic Properties of Low Coercivity Magnetic Materials Using Hysteresig-raphsA811 Specification for Soft Magnetic Iron Parts Fabricate
11、d by Powder Metallurgy TechniquesA839 Specification for Iron-Phosphorus Powder Metallurgy Parts for Soft Magnetic ApplicationsA904 Specification for 50 Nickel-50 Iron Powder Metallurgy Soft Magnetic PartsA927/A927M Test Method for Alternating-Current Magnetic Properties of Toroidal Core Specimens Us
12、ing the Voltmeter-Ammeter-Wattmeter Method1 This practice is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.02on Base Metal Powders.Current edition approved July 15, 2008April 15, 2015. Published August 200
13、8May 2015. Originally approved in 2003. Last previous edition approved in 20032008 asB925 03.B925 08. DOI: 10.1520/B0925-08.10.1520/B0925-15.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolum
14、e information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequa
15、tely depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appears at the end of this standardCopyright ASTM In
16、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyB312 Test Method for Green Strength of Specimens Compacted from Metal PowdersB328 Test Method for Density, Oil Content, and I
17、nterconnected Porosity of Sintered Metal Structural Parts and Oil-ImpregnatedBearings (Withdrawn 2009)3B331 Test Method for Compressibility of Metal Powders in Uniaxial CompactionB438 Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)B439 Specification for Iron-Base Powd
18、er Metallurgy (PM) Bearings (Oil-Impregnated)B528 Test Method for Transverse Rupture Strength of Powder Metallurgy (PM) SpecimensB595 Specification for Sintered Aluminum Structural PartsB610 Test Method for Measuring Dimensional Changes Associated with Processing Metal PowdersB715 Specification for
19、Sintered Copper Structural Parts for Electrical Conductivity Applications (Withdrawn 2010)3B783 Specification for Materials for Ferrous Powder Metallurgy (PM) Structural PartsB817 Specification for Powder Metallurgy (PM) Titanium Alloy Structural Components (Withdrawn 2013)3B823 Specification for Ma
20、terials for Copper Base Powder Metallurgy (PM) Structural PartsB853 Specification for Powder Metallurgy (PM) Boron Stainless Steel Structural ComponentsB939 Test Method for Radial Crushing Strength, K, of Powder Metallurgy (PM) Bearings and Structural MaterialsB962 Test Methods for Density of Compac
21、ted or Sintered Powder Metallurgy (PM) Products Using Archimedes PrincipleB963 Test Methods for Oil Content, Oil-Impregnation Efficiency, and Surface-Connected Porosity of Sintered PowderMetallurgy (PM) Products Using Archimedes PrincipleE8 Test Methods for Tension Testing of Metallic MaterialsE9 Te
22、st Methods of Compression Testing of Metallic Materials at Room TemperatureE18 Test Methods for Rockwell Hardness of Metallic MaterialsE23 Test Methods for Notched Bar Impact Testing of Metallic MaterialsE228 Test Method for Linear Thermal Expansion of Solid Materials With a Push-Rod DilatometerE187
23、6 Test Method for Dynamic Youngs Modulus, Shear Modulus, and Poissons Ratio by Impulse Excitation of Vibration2.2 IEEE/ASTM Standard:SI 10 Standard for Use of the International System of Units (SI): The Modern Metric System22.2 MPIF Standard:Standard 56 Method for Determination of Rotating Beam Fati
24、gue Endurance Limit in Powder Metallurgy Materials43. Terminology3.1 DefinitionsDefinitions of powder metallurgy terms can be found in Terminology B243.Additional descriptive informationis available in the Related Materials section of Vol 02.05 of the Annual Book of ASTM Standards.4. Summary of Prac
25、tice4.1 These practices describe the production, by pressing and sintering metal powders, and the preparation, by machiningsintered blanks, of test specimens used to measure properties of metal powders and sintered materials.5. Significance and Use5.1 Test specimens are used to determine the enginee
26、ring properties of PM materials, for example, tensile strength, ductility,impact energy, etc.; property data that are essential to the successful use of PM material standards. Processing PM test specimensunder production conditions is the most efficient method by which to obtain reliable PM material
27、 property data since in most casesit is impractical or impossible to cut test bars from sintered parts.5.2 The performance characteristics of metal powders, for example, compressibility, green strength and dimensional changesassociated with processing are evaluated using PM test specimens under cont
28、rolled conditions. The data obtained are importantto both metal powder producers and PM parts manufacturers.5.3 PM test specimens play a significant role in industrial quality assurance programs. They are used to compare properties ofa new lot of metal powder with an established lot in an acceptance
29、 test and are used in the part manufacturing process to establishand adjust production variables.5.4 In those instances where it is required to present equivalent property data for a production lot of PM parts, standard testspecimens compacted from the production powder mix to the same green density
30、 can be processed with the production PM partsand then tested to obtain this information.3 The last approved version of this historical standard is referenced on www.astm.org.4 Available from MPIF, 105 College Road East, Princeton, NJ 08540.B925 1525.5 Material property testing performed for industr
31、ial or academic research and development projects uses standard PM testspecimens so the test results obtained can be compared with previous work or published data.5.6 Powder metallurgy test specimens may have multiple uses.The dimensions and tolerances given in this standard are nominalin many cases
32、. The user is cautioned to make certain that the dimensions of the test specimen are in agreement with therequirements of the specific test method to be used.6. Powder Metallurgy Test SpecimensPOWDER COMPRESSIBILITY TESTING6.1 Cylindrical Powder Compressibility Test Specimen:6.1.1 Description and Us
33、eThis solid cylindrical test specimen, see Fig. 1, is produced by compacting a test portion of powdermix in laboratory powder metallurgy tooling similar to that shown in Fig. A1.1 in the Annex. An alternative test specimen formeasuring powder compressibility is the transverse rupture test specimen.
34、These test specimens are not sintered. Thecompressibility of the metal powder mix or a compressibility curve showing the green density as a function of compacting pressureis determined according to the procedures in Test Method B331.6.1.2 Applicable ASTM Standards:6.1.2.1 See Test Method B331.TRANSV
35、ERSE RUPTURE, DIMENSIONAL CHANGE AND GREEN STRENGTH TESTING6.2 Transverse Rupture Strength Test Specimen:6.2.1 Description and UseThe pressed-to-size transverse rupture 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
36、test specimen has multiple uses in PM. Primarily, it is designed to determine the transverse rupturestrength of sintered or heat treated compacts by breaking the test specimen as a simple beam in three-point loading following TestMethod B528. But, it is also used to measure the dimensional changes o
37、f metal powder mixes due to pressing and sintering or otherprocessing steps according to Test Method B610, and it is used in both a 0.250 and 0.500 in. (6.35 and 12.70 mm) thick versionto determine green strength using the procedure in Test Method B312.6.2.1.2 It is an acceptable alternative test sp
38、ecimen to the cylindrical compact to determine powder compressibility accordingto Test Method B331. The sintered or heat treated specimen may be used to generate data for the elastic constants. YoungsModulus is determined by impulse excitation of vibration and Poissons ratio may then be calculated.
39、This test specimen is alsoa convenient compact on which to measure macroindentation hardness after various processing steps.Dimensionsin. mmDDiameter 1.00 25.4TCompact thickness 0.280 0.010 7.11 0.25Dimensionsin. mmDDiameter 1.00 (25.4)TCompact thickness 0.280 0.010 (7.11 0.25)FIG. 1 PM Cylindrical
40、Powder Compressibility Test SpecimenB925 1536.2.2 Applicable ASTM Standards:6.2.2.1 See the following Test Methods: B312, B331, B528, B610, E18, and E1876.6.2.2.2 See the following PM Material Specifications: A811, A839, A904, B783, and B823.RADIAL CRUSHING STRENGTH TESTING6.3 Radial Crushing Streng
41、th Test Specimen:6.3.1 Description and UseThe radial crushing strength test specimen shown in Fig. 3 is compacted to size in tooling (Fig.A2.3) suitable for the production of a thin-walled hollow cylinder within the range of the dimensions listed. The testing procedureinvolves the application of a c
42、ompressive force perpendicular to the central axis of the test cylinder and calculating the radialcrushing strength from the breaking load and test specimen dimensions. Radial crushing strength is the material property that isused to quantify the mechanical strength of sintered metal bearings, (oil-
43、impregnated).6.3.1.1 Radial Crushing Strength is determined following the procedure in Test Method B939.6.3.1.2 This test specimen is widely used in a quality control test to determine the sintered material strength of metal powdermixtures that are to be used for the production of any metal powder p
44、roduct because it is a quick, easy test and gives reliable andreproducible results. Laboratories testing powder mixes intended for the manufacture of porous bearings have recognized thatbreaking an unsintered test specimen by diametrical loading will give a green strength value that is relevant in p
45、roduction.6.3.1.3 Laboratories testing powder mixes intended for the manufacture of porous bearings have recognized that using a hollowcylindrical test specimen for dimensional change measurements and determination of green strength will give values that arerelevant in production.6.3.1.4 This specim
46、en finds use in determining oil content, impregnation efficiency and interconnected porosity of PM bearingmaterials following the procedures in Test Methods B963.6.3.2 Applicable ASTM Standards:6.3.2.1 See Test Method B939.6.3.2.2 See the following PM Bearing Specifications: B438 and B439.TENSION TE
47、STING6.4 Flat Unmachined Tension Test Specimen:6.4.1 Description and UseThe unmachined flat tension test specimen shown in Fig. 4 is commonly referred to in the industryas “the dogbone.” It is compacted directly to size and shape using tooling similar to that shown in Fig. A2.4 in the Annex. Thistes
48、t specimen has been designed to have a convenient 1.00 in.2 (645.2 mm2) pressing area to simplify compacting calculations.Dimensionsin. mmWWidth 0.50 12.7LLength 1.25 31.8RCorner radius 0.01 0.3TThickness (thin) 0.250 0.005 6.35 0.13TThickness (thick) 0.500 0.005 12.70 0.13Dimensionsin. mmWWidth 0.5
49、0 (12.7)LLength 1.25 (31.8)RCorner radius 0.01 (0.3)TThickness (thin) 0.250 0.005 (6.35 0.13)TThickness (thick) 0.500 0.005 (12.70 0.13)NOTE 1Thickness shall be parallel within 0.005 in. (0.13 mm).FIG. 2 PM Transverse Rupture Strength Test SpecimenB925 1546.4.1.1 It is intended for determining the tensile properties and ductility of PM materials that have not been heat treated (notquenched and tempered nor sinter-hardened). The testing procedures for this unmachined PM test specimen can be found in TestMethod E8.6.4.1.2 The f
