1、Designation: B610 08B610 13Standard Test Method forMeasuring Dimensional Changes Associated withProcessing Metal Powders1This standard is issued under the fixed designation B610; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year 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 This standard covers a test method that may be used to measure the sum of the changes in dimensions that occu
3、r when ametal powder is first compacted into a test specimen and then sintered.1.2 The dimensional change is determined by a quantitative laboratory procedure in which the arithmetic difference betweenthe dimensions of a die cavity and the dimensions of a sintered test specimen produced from that di
4、e is calculated and expressedas a percent growth or shrinkage.1.3 With the exception of density values, the values for density and the mass used to determine density, for which the g/cmuseof the gram per cubic centimetre (g/cm3 unit ) and gram (g) units is the long-standing industry standard,practic
5、e, the values statedin inch-pound units are to be regarded as the standard. The SI equivalents shown in parentheses, have been converted in accordancewith IEEE/ASTM Standard SI 10, may be approximate, and are only for information.values given in parentheses are mathematicalconversions to SI units th
6、at are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the
7、applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B215 Practices for Sampling Metal PowdersB243 Terminology of Powder MetallurgyB328 Test Method for Density, Oil Content, and Interconnected Porosity of Sintered Metal Structural Parts and Oil-ImpregnatedBe
8、arings (Withdrawn 2009)3B925 Practices for Production and Preparation of Powder Metallurgy (PM) Test SpecimensIEEE/ASTM SI 10B962 American National Standard for Metric PracticeTest Methods for Density of Compacted or SinteredPowder Metallurgy (PM) Products Using Archimedes Principle3. Terminology3.1
9、 DefinitionsThe definitions of the Powder Metallurgy (PM) terms that are used in this test method are found inTerminology B243. Additional descriptive information is available in the Related Material section of Vol.02.05 Vol. 02.05 of theAnnual Book of ASTM Standards.4. Summary of Test Method4.1 Rec
10、tangular test specimens are compacted to a target green density from a metal powder or metal powder mixture andsintered under controlled conditions.4.2 The absolute dimensional change, expressed as a growth or shrinkage percentage is calculated from the difference betweenthe long dimension of the di
11、e cavity and the long dimension of the sintered test specimen.1 This test method is under the jurisdiction ofASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.02on Base Metal Powders.Current edition approved Aug. 1, 2008May 1, 2013. Pu
12、blished September 2008June 2013. Originally approved in 1976. Last previous edition approved in 20002008 asB610 - 00B610 08. 1. DOI: 10.1520/B0610-08.10.1520/B0610-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual B
13、ook of ASTM Standardsvolume 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 tech
14、nically possible to adequately 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
15、 standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.3 The comparative dimensional change requires specimens from a reference metal powder lot agreed upon by the partiesconcerned to be produced and processed at the same time. Th
16、e dimensional change of the specimens from the test powder iscalculated and mathematically compared with the dimensional change of the specimens from the reference powder.5. Significance and Use5.1 Dimensional Change When Compacting and Sintering Metal Powders:5.1.1 The dimensional change value obta
17、ined under specified conditions of compacting and sintering is a material characteristicinherent in the powder.5.1.2 The test is useful for quality control of the dimensional change of a metal powder mixture, to measure compositional andprocessing changes and to guide in the production of PM parts.5
18、.1.3 The absolute dimensional change may be used to classify powders or differentiate one type or grade from another, toevaluate additions to a powder mixture or to measure process changes, and to guide in the design of tooling.5.1.4 The comparative dimensional change is mainly used as a quality con
19、trol test to measure variations between a lot orshipment of metal powder and a reference powder of the same material composition.5.1.5 Factors known to affect size change are the base metal powder grade, type and lot, particle size distribution, level and typesof additions to the base metal powder,
20、amount and type of lubricant, green density, as well as processing conditions of the testspecimen; heating rate, sintering time and temperature, sintering atmosphere, and cooling rate.5.2 Dimensional Change of Various PM Processing Steps:5.2.1 The general procedure of measuring the die or a test com
21、pact before and after a PM processing step, and calculating apercent dimensional change is also adapted for use as an internal process evaluation test to quantify green expansion, repressingsize change, heat treatment changes or other changes in dimensions that result from a manufacturing operation.
22、6. Apparatus6.1 Balance, having the capacity to determine a balance readable to 0.0001 g with a minimum capacity of 200 g to be used fordetermining the mass of the test portion of powder and the mass of the test specimen to an accuracy of specimens to the nearest0.001 g.6.2 Compacting Tool Set, a PM
23、 die and punches designed to produce the rectangular test specimen, an example of which isshown in Practices, B925, as Typical Laboratory Tooling Transverse Rupture Test Specimen.6.3 Inside and Outside Micrometer or Calipers, or other suitable measuring apparatus of the size necessary to measure the
24、 longdimensions of the die cavity and sintered test specimens to 0.0001 in. (0.0025 mm).6.4 Universal Testing Machine or PM Compacting Press, suitable for holding the tooling and having sufficient force to applythe pressure necessary to compact the test specimen to the target green density.6.5 Sinte
25、ring Furnace, a laboratory or production furnace capable of heating the specimens to a specified work temperature,holding them at that temperature and cooling to room temperature in a controlled atmosphere or vacuum.7. Test Specimen7.1 A rectangular compact, having dimensions of 0.500 in. (12.70 mm)
26、 wide by 1.250 in. (31.75 mm) long by 0.250 in. (6.35mm) thick, as shown in Fig. 2 in Practices B925 as the PM Transverse Rupture Strength Test Specimen thin, is the recommendedtest specimen.7.2 The top and bottom faces of the green compact shall be parallel within 0.001 in. (0.03 mm).7.3 The green
27、density shall be within 0.05 g/cm3 of the agreed target density.7.4 Alternative test specimens that may be used to measure PM dimensional changes are the Cylindrical PowderCompressibility Test Specimen, the Radial Crushing Strength Test Specimen or the Ring Test Specimen for Measuring MagneticProper
28、ties, all of which are shown in Practices B925. These other test specimens are primarily used for in-house testing by bearingand structural parts manufacturers to determine the change in dimensions of powder and parts at every step of their manufacturingprocess.8. Procedure8.1 PreliminaryPreliminary
29、:8.1.1 When this dimensional change test method is used to approve a shipment of metal powder, all testing conditions includingthe value of the target green density and the selection and performance criterion of the reference lot shall be agreed upon by themanufacturer and purchaser.8.1.2 Using the
30、nominal dimensions of the test specimen, calculate and note the mass of powder that will be needed to produceone test specimen to the target green density. (Formula #1).8.1.3 Set up the tooling in the PM compacting press or universal testing machine.B610 1328.1.4 Measure the long dimension of the di
31、e cavity, (LD), to 0.0001 in. (0.0025 mm) and note for later use.8.2 Powder PreparationPowder Preparation:8.2.1 Metal powders containing a lubricant are normally tested in the as-received condition. When testing unlubricated powders,the method of lubrication, either die-wall or admixing, shall be a
32、matter of agreement between the parties concerned.8.2.2 If an admixed lubricant is to be used to prepare the powder for compacting, the type, grade, percentage and mixingprocedure shall be agreed upon between the concerned parties or shall closely follow accepted PM practice.8.2.3 Following the proc
33、edure in Practices B215, take a gross sample from the lot of the lubricated or unlubricated metal powderthat is to be tested (and reference metal powder, if used) of sufficient quantity to produce at least three test specimens.8.2.4 Next, drawtake three test portions of powder from the gross sample,
34、 each of which has a mass within 0.02 g of the masscalculated in 8.1.2.8.3 CompactingCompacting:8.3.1 If die-wall-lubrication is chosen for compacting unlubricated powders, it shall be applied prior to the compacting of eachtest specimen following the procedures in Practices B925.8.3.2 Pour the test
35、 portion of the powder that is to be tested evenly into the die cavity.8.3.3 Using the required pressure, compact the test specimen (and the reference specimen, if used) to the target green densityin accordance with the procedure contained in Practices B925.8.3.4 Eject the test specimen from the die
36、, determine the mass to the nearest 0.001 g, measure the specimen dimensions to thenearest 0.001 in. (0.03 mm), identify and number the specimen.8.3.5 Repeat to obtain three specimens of the test powder (and three reference specimens, if used).8.3.6 Determine the green density of each test specimen
37、(and each reference specimen, if used) following the procedure in TestMethod B328B962, or8.3.7 Calculate the green density from the measurements and mass of each specimen as follows:DG 50.061 MW T L (1)where:DG = green density of the test (reference) specimen, g/cm3,0.061 = conversion factor, in3 to
38、 cm3,M = mass of the green test (reference) specimen, g,W = width of green test (reference) specimen, in.,T = thickness of the green test (reference) specimen, in., andL = length of the green test (reference) specimen, in.8.4 SinteringSintering:8.4.1 When the dimensional change test is conducted to
39、approve a metal powder lot for production use, it is desirable to usethe production furnace or at least sintering equipment that simulates or approximates production conditions.8.4.2 Sinter the test specimens (with three reference specimens, if used) using the production conditions or a heating rate
40、,sintering atmosphere, sintering time and temperature, and cooling rate suitable for the material being tested.8.4.3 After cooling to room temperature, measure the long dimension of each sintered specimen to 0.0001 in. (0.0025 mm).Record this dimension, (LT), and (LR) for the reference specimens, if
41、 used, for use later in the calculations.9. CalculationsABSOLUTE DIMENSIONAL CHANGE9.1 Calculate the percent absolute dimensional change (DCT) for the specimens produced from the test powder as follows:DCT,%5LT 2LD!3100LD(2)where:LD = long dimension of the die cavity, in. (mm), (see 8.1.4).LT = long
42、 dimension of the sintered specimen produced from the test powder, in. (mm), (see 8.4.3).where:LD = long dimension of the die cavity, in. (mm), (see 8.1.4).LT = long dimension of the sintered specimen produced from the test powder, in. (mm), (see 8.4.3).COMPARATIVE DIMENSIONAL CHANGE9.2 Calculate th
43、e percent absolute dimensional change (DCR) for the specimens produced from the reference powder as follows:DCR,%5LR 2LD!3100LD(3)B610 133where:LD = long dimension of the die cavity, in. (mm), (see 8.1.4), andLR = = long dimension of the sintered specimen produced from the reference powder, in. (mm)
44、, (see 8.4.3).where:LD = long dimension of the die cavity, in. (mm), (see 8.1.4), andLR = = long dimension of the sintered specimen produced from the reference powder, in. (mm), (see 8.4.3).9.3 The percent absolute dimensional change of the specimens produced from the reference powder shall be withi
45、n the limitsagreed to between the powder producer and the purchaser in order to have a valid test.9.4 Then, using the absolute dimensional change for the test powder from 9.1 calculate the percent comparative dimensionalchange (DC) as the difference between the specimens from the test powder and the
46、 reference powder as follows:DC,%5DCT 2DCR (4)10. Report10.1 The general reporting format shall be: Dimensional Change at (specified) Green Density.10.1.1 Report the absolute dimensional change from die size for the specimens made from the test powder (DCT), as themathematical average of the three s
47、pecimens, calculated to the nearest 0.01 %, including the sign of plus (+) for growth and minus() for shrinkage.10.1.2 Report the comparative dimensional change between the test powder and the reference powder (DC), as the mathematicaldifference between the average absolute dimensional change from d
48、ie size for the three specimens made from the test powder andthose from the reference powder as a percent to the nearest 0.01 %, including the sign of (+) or () to indicate direction of thedeviation.NOTE 1If the % dimensional change is divided by 100, the results then will be expressed in in/in (mm/
49、mm) units.10.1.3 Report the green density to the nearest 0.01 g/cm3 as the average density of the three test specimens (and the threereference specimens, if used).10.2 An alternative reporting method may be to graph the dimensional change as a function of the green density using the resultsobtained at a minimum of three data points.10.3 The following supplementary information should also be reported in order to clarify and understand the test results.10.3.1 Identification of the metal powder by brand, grade, and lot number,10.3.2 Chemical composition of the powder
