1、Designation: B 610 00e1Standard Test Method forMeasuring Dimensional Changes of Metal PowderSpecimens1This standard is issued under the fixed designation B 610; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.e1NOTEEditorial corrections were made in Sections 5, 8.6, 9, and 10.4 and Fig. 2.1. Scope1.1 This test method primarily covers a procedure
3、fordetermining the change in dimensions that occurs as a result ofpressing and sintering a metal powder specimen. The sizechange referred to is the difference between the die size and thesize of the sintered specimen after it has cooled to roomtemperature, expressed as a percentage. This size change
4、 is abasic characteristic of the metal powder.1.2 The general procedure of measuring a test specimen anddie, then calculating the dimensional change, as described inthis test method, also may be used to determine green expan-sion, heat treat changes, or other dimensional changes of testspecimens tha
5、t result from processing steps.1.3 The values stated in inch-pound units are to be regardedas the standard. The SI equivalents are in parentheses and maybe approximate.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of
6、 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:B 215 Practices for Sampling Finished Lots of Metal Pow-ders2B 243 Terminology of Powder Metallurgy2B 312
7、 Test Method for Green Strength for CompactedMetal Powder Specimens23. Terminology3.1 DefinitionsFor definitions of terms used in this testmethod, see Terminology B 243.4. Summary of Test Method4.1 Test specimens are made from the metal powder lotunder consideration by pressing and sintering or othe
8、r process-ing (see 1.2). The absolute dimensional change as a result ofpressing and sintering is calculated from measurements takenon the sintered test specimens and from the die cavity.4.2 When this method is used to compare metal powder lots,specimens from a reference metal powder lot agreed upon
9、bythe parties concerned are made and processed at the same time.The dimensional change of the test specimen is calculated andmathematically compared with the dimensional change of thereference specimen.5. Significance and Use5.1 The dimensional change obtained under specified con-ditions of pressing
10、 and sintering is a material characteristicinherent in the powder. It is useful to the production, testing,and use of metal powders.5.2 The absolute dimensional change may be used toclassify powders or differentiate one type or grade fromanother, to evaluate additions to the powder mix or measurepro
11、cess changes, and to guide in the design of tooling.5.3 The comparative dimensional change is mainly used asa quality control test to measure variations between lots ofmetal powders of the same material composition.5.4 Factors known to affect size change are the test speci-men process conditions of
12、green density, sinter time, sintertemperature, sinter atmosphere, level of additions to the basemetal powder, lubricant type, powder grade, powder type, andpowder lot.6. Apparatus6.1 Balance, suitable for weighing accurately to 0.01 g.6.2 Mixer, capable of thorough and controlled mixing ofmetal powd
13、ers and lubricants.6.3 Compression-Testing Machine or Powder Press, ca-pable of applying the required pressure to produce the testspecimen.6.4 Punches and Die, for producing a test specimen, areshown in Fig. 1.6.5 Micrometers, capable of measuring the necessary di-mensions to 0.0001 in. (0.0025 mm).
14、6.6 Sintering Furnace, capable of maintaining a specifiedwork temperature and having controlled atmosphere and a1This test method is under the jurisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.02 on Base Metal Powders.C
15、urrent edition approved April 10, 2000. Published June 2000. Originallypublished as B 610 - 76. Last previous edition B 610 - 93.2Annual Book of ASTM Standards, Vol 02.05.1Copyright ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.water-jacketed cooling zone. A vacuum fur
16、nace also is permit-ted.6.7 When the dimensional change test is run to approvemetal powders for production, it is preferable to use sinteringconditions that approximate or simulate production conditions.7. Test Specimen7.1 The green test specimen, having nominal dimensions of0.500 in. (12.70 mm) wid
17、e by 1.250 in. (31.75 mm) long by0.250 in. (6.35 mm) thick, as shown in Fig. 2, is therecommended test specimen.8. Procedure8.1 Measure the long dimension of the die cavity to 0.0001in. (0.0025 mm). Note this dimension, LD, for future reference.8.2 Obtain a test sample of the test metal powder (andr
18、eference metal powder, if used) in accordance with PracticeB 215.8.3 Compact three test specimens (and three referencespecimens, if used) in accordance with Test Method B 312.8.4 Sinter the test specimens (with three reference speci-mens, if used) using a heating rate, sintering time and tempera-tur
19、e, and cooling rate suitable for the material being tested.8.5 When the dimensional change method is used to ap-prove a metal powder lot, all powder and processing conditionsshall be agreed upon by the parties concerned.8.6 Measure the long dimension of the sintered specimensto 0.0001 in. (0.0025 mm
20、). Note this dimension, LTand LRforreference specimens, if used, , for later calculation use.9. Calculation9.1 Absolute Dimensional Change:9.1.1 Calculate the percent dimensional change (DT) for thespecimens from the test powder as follows:DT,%5 LT LD!/LD3 100 (1)where:LT= long dimension of sintered
21、 test specimen (see 8.6)andLD= long dimension of the die cavity (see 8.1).9.1.2 Calculate the percent dimensional change (DR) for thespecimens from the reference powder as follows:DR,%5 LR LD!/LD3 100 (2)where:LR= long dimension of sintered reference specimen (see8.6).9.2 Comparative Dimensional Cha
22、ngeCalculate the com-parative dimensional change (D) as follows:D,%5 DT DR(3)10. Report10.1 Report the absolute dimensional change from die sizefor the specimens made from the test powder (DT), and thosefrom the reference powder (DR), as the average of the threespecimens, calculated to the nearest 0
23、.01 %, including the signof + for growth and for shrinkage.10.2 Report the comparative dimensional change (D), as themathematical difference between the average absolute dimen-sional change from die size for the specimens made from thetest powder and those from the reference powder as a percentto th
24、e nearest 0.01 %, including the sign of + or to indicatedirection of the difference.NOTE 1If the % dimensional change is divided by 100, the resultsthen will be expressed in in./in. (mm/mm).10.3 The following supplementary information should bereported for clarification:10.3.1 Identification of powd
25、er, brand, grade, and lot num-ber.10.3.2 Chemistry of powder mix used if other than elemen-tal powders are being tested.10.3.3 Type, brand and percent of lubricant or the additives,10.3.4 Compacting pressure,10.3.5 Green density,10.3.6 Sintering temperature,10.3.7 Sintering time, as defined as the e
26、lapsed time for theheated specimen to be within 615F (68C) of the statedsintering temperature for iron and 610F (65C) for copperbase, andNOTE 1The dimensions for the cavity shall be 0.500 6 0.004 in. wide(12.70 6 0.10 mm) by 1.250 6 0.004 in. long (31.75 6 0.10 mm). Themating parts shall fit freely
27、and should be finished to 4 in. (N3) or betterto dimensions of 0.0005 in. (0.013 mm) to 0.0010 in. (0.025 mm) smallerthan the die cavity in each dimension. The dimensions given in thedrawing typify the die cavity and punch within the stated tolerance at thenormal width and length.FIG. 1 Example of T
28、ooling to Produce the Test SpecimenFIG. 2 Dimensional Change Test SpecimenB 610210.3.8 Furnace atmosphere.10.4 The absolute dimensional change (DR) of the speci-mens made from the reference metal powder shall be within thelimits agreed upon between the parties concerned in order tohave a valid test.
29、11. Precision and Bias11.1 The precision and bias of this test method is currentlyunder development in Subcommittee B09.02 on Base MetalPowders.12. Keywords12.1 die size; dimensional change; metal powders; sinteringThe American Society for Testing and Materials takes no position respecting the valid
30、ity of any patent rights asserted in connectionwith any item mentioned in this standard. Users of this standard are expressly advised that determination of the validity of any suchpatent rights, and the risk of infringement of such rights, are entirely their own responsibility.This standard is subje
31、ct to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Headquarters. Your comm
32、ents will receive careful consideration at a meeting of the responsibletechnical committee, which you may attend. If you feel that your comments have not received a fair hearing you should make yourviews known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighte
33、d by ASTM, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the above address or at610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website (www.astm.org).B 6103
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