ASTM B610-2008 Standard Test Method for Measuring Dimensional Changes Associated with Processing Metal Powders《与处理金属粉末相关测定尺寸变化的标准试验方法》.pdf

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1、Designation: B 610 08Standard Test Method forMeasuring Dimensional Changes Associated withProcessing Metal Powders1This 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

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 This standard covers a test method that may be used tomeasure the sum of the changes in dimensions that occur when

3、a metal powder is first compacted into a test specimen and thensintered.1.2 The dimensional change is determined by a quantitativelaboratory procedure in which the arithmetic difference be-tween the dimensions of a die cavity and the dimensions of asintered test specimen produced from that die is ca

4、lculated andexpressed as a percent growth or shrinkage.1.3 With the exception of density values, for which theg/cm3unit is the industry standard, the values stated ininch-pound units are to be regarded as the standard. The SIequivalents shown in parentheses, have been converted inaccordance with IEE

5、E/ASTM Standard SI 10, may be approxi-mate, and are only for information.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine

6、the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2B 215 Practices for Sampling Metal PowdersB 243 Terminology of Powder MetallurgyB 328 Test Method for Density, Oil Content, and Intercon-nected Porosity of Sintered Metal Structural Parts andOil-Impr

7、egnated BearingsB 925 Practices for Production and Preparation of PowderMetallurgy (PM) Test SpecimensSI 10 American National Standard for Use of the Interna-tional System of Units (SI): The Modern Metric System3. Terminology3.1 DefinitionsThe definitions of the Powder Metallurgy(PM) terms that are

8、used in this test method are found inTerminology B 243. Additional descriptive information isavailable in the Related Material section of Vol.02.05 of theAnnual Book of ASTM Standards.4. Summary of Test Method4.1 Rectangular test specimens are compacted to a targetgreen density from a metal powder o

9、r metal powder mixtureand sintered under controlled conditions.4.2 The absolute dimensional change, expressed as a growthor shrinkage percentage is calculated from the differencebetween the long dimension of the die cavity and the longdimension of the sintered test specimen.4.3 The comparative dimen

10、sional change requires speci-mens from a reference metal powder lot agreed upon by theparties concerned to be produced and processed at the sametime. The dimensional change of the specimens from the testpowder is calculated and mathematically compared with thedimensional change of the specimens from

11、 the referencepowder.5. Significance and Use5.1 Dimensional Change When Compacting and SinteringMetal Powders:5.1.1 The dimensional change value obtained under speci-fied conditions of compacting and sintering is a materialcharacteristic inherent in the powder.5.1.2 The test is useful for quality co

12、ntrol of the dimensionalchange of a metal powder mixture, to measure compositionaland processing changes and to guide in the production of PMparts.5.1.3 The absolute dimensional change may be used toclassify powders or differentiate one type or grade fromanother, to evaluate additions to a powder mi

13、xture or tomeasure process changes, and to guide in the design of tooling.1This 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.Current edition approved Aug. 1, 2008.

14、Published September 2008. Originallyapproved in 1976. Last previous edition approved in 2000 as B 610 - 001.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the stan

15、dards 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.5.1.4 The comparative dimensional change is mainly usedas a quality cont

16、rol test to measure variations between a lot orshipment of metal powder and a reference powder of the samematerial composition.5.1.5 Factors known to affect size change are the base metalpowder grade, type and lot, particle size distribution, level andtypes of additions to the base metal powder, amo

17、unt and typeof lubricant, green density, as well as processing conditions ofthe test specimen; 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 testcompact b

18、efore and after a PM processing step, and calculatinga percent dimensional change is also adapted for use as aninternal process evaluation test to quantify green expansion,repressing size change, heat treatment changes or otherchanges in dimensions that result from a manufacturing opera-tion.6. Appa

19、ratus6.1 Balance, having the capacity to determine the mass ofthe test portion of powder and the mass of the test specimen toan accuracy of 0.001 g.6.2 Compacting Tool Set, a PM die and punches designed toproduce the rectangular test specimen, an example of which isshown in Practices, B 925, as Typi

20、cal Laboratory Tooling Transverse Rupture Test Specimen.6.3 Inside and Outside Micrometer or Calipers, of the sizenecessary to measure the long dimensions of the die cavity andsintered test specimens to 0.0001 in. (0.0025 mm).6.4 Universal Testing Machine or PM Compacting Press,suitable for holding

21、the tooling and having sufficient force toapply the pressure necessary to compact the test specimen tothe target green density.6.5 Sintering Furnace, a laboratory or production furnacecapable of heating the specimens to a specified work tempera-ture, holding them at that temperature and cooling to r

22、oomtemperature in a controlled atmosphere or vacuum.7. Test Specimen7.1 A rectangular compact, having dimensions of 0.500 in.(12.70 mm) wide by 1.250 in. (31.75 mm) long by 0.250 in.(6.35 mm) thick, as shown in Fig. 2 in Practices B 925 as thePM Transverse Rupture Strength Test Specimen thin is ther

23、ecommended test specimen.7.2 The top and bottom faces of the green compact shall beparallel within 0.001 in. (0.03 mm).7.3 The green density shall be within 0.05 g/cm3of theagreed target density.7.4 Alternative test specimens that may be used to measurePM dimensional changes are the Cylindrical Powd

24、er Com-pressibility Test Specimen, the Radial Crushing Strength TestSpecimen or the Ring Test Specimen for Measuring MagneticProperties, all of which are shown in Practices B 925. Theseother test specimens are primarily used for in-house testing bybearing and structural parts manufacturers to determ

25、ine thechange in dimensions of powder and parts at every step of theirmanufacturing process.8. Procedure8.1 Preliminary8.1.1 When this dimensional change test method is used toapprove a shipment of metal powder, all testing conditionsincluding the value of the target green density and the selectiona

26、nd performance criterion of the reference lot shall be agreedupon by the manufacturer and purchaser.8.1.2 Using the nominal dimensions of the test specimen,calculate and note the mass of powder that will be needed toproduce one test specimen to the target green density. (Formula#1).8.1.3 Set up the

27、tooling in the PM compacting press oruniversal testing machine.8.1.4 Measure the long dimension of the die cavity, (LD), to0.0001 in. (0.0025 mm) and note for later use.8.2 Powder Preparation8.2.1 Metal powders containing a lubricant are normallytested in the as-received condition. When testing unlu

28、bricatedpowders, the method of lubrication, either die-wall or admix-ing, shall be a matter of agreement between the partiesconcerned.8.2.2 If an admixed lubricant is to be used to prepare thepowder for compacting, the type, grade, percentage and mixingprocedure shall be agreed upon between the conc

29、erned partiesor shall closely follow accepted PM practice.8.2.3 Following the procedure in Practices B 215, take agross sample from the lot of the lubricated or unlubricatedmetal powder that is to be tested (and reference metal powder,if used) of sufficient quantity to produce at least three testspe

30、cimens.8.2.4 Next, draw three test portions of powder from thegross sample, each of which has a mass within 0.02 g of themass calculated in 8.1.2.8.3 Compacting8.3.1 If die-wall-lubrication is chosen for compacting unlu-bricated powders, it shall be applied prior to the compacting ofeach test specim

31、en following the procedures in PracticesB 925.8.3.2 Pour the test portion of the powder that is to be testedevenly into the die cavity.8.3.3 Using the required pressure, compact the test speci-men (and the reference specimen, if used) to the target greendensity in accordance with the procedure conta

32、ined in PracticesB 925.8.3.4 Eject the test specimen from the die, determine themass to the nearest 0.001 g, measure the specimen dimensionsto the nearest 0.001 in. (0.03 mm), identify and number thespecimen.8.3.5 Repeat to obtain three specimens of the test powder(and three reference specimens, if

33、used).8.3.6 Determine the green density of each test specimen(and each reference specimen, if used) following the procedurein Test Method B 328,orB6100828.3.7 Calculate the green density from the measurementsand mass of each specimen as follows:DG5 0.061MWTL(1)DG= green density of the test (referenc

34、e) specimen,g/cm3,0.061 = conversion factor, in3to 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 Sintering8.4.1 When the d

35、imensional change test is conducted toapprove a metal powder lot for production use, it is desirable touse the production furnace or at least sintering equipment thatsimulates or approximates production conditions.8.4.2 Sinter the test specimens (with three reference speci-mens, if used) using the p

36、roduction conditions or a heating rate,sintering atmosphere, sintering time and temperature, andcooling rate suitable for the material being tested.8.4.3 After cooling to room temperature, measure the longdimension of each sintered specimen to 0.0001 in. (0.0025mm). Record this dimension, (LT), and

37、(LR) for the referencespecimens, if 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 asfollows:DCT,%5LT LD! 3 100LD(2)where:LD= long dimension of the die cavity

38、, in. (mm), (see8.1.4).LT= long dimension of the sintered specimen producedfrom the test powder, in. (mm), (see 8.4.3).COMPARATIVE DIMENSIONAL CHANGE9.2 Calculate the percent absolute dimensional change(DCR) for the specimens produced from the reference powderas follows:DCR,%5 LR LD! 3 100LD(3)where

39、:LD= long dimension of the die cavity, in. (mm), (see8.1.4), andLR= = long dimension of the sintered specimen producedfrom the reference powder, in. (mm), (see 8.4.3).9.3 The percent absolute dimensional change of the speci-mens produced from the reference powder shall be within thelimits agreed to

40、between the powder producer and the pur-chaser in order to have a valid test.9.4 Then, using the absolute dimensional change for the testpowder from 9.1 calculate the percent comparative dimen-sional change (DC) as the difference between the specimensfrom the test powder and the reference powder as

41、follows:DC,%5 DCT DCR(4)10. Report10.1 The general reporting format shall be: DimensionalChange at (specified) Green Density.10.1.1 Report the absolute dimensional change from diesize for the specimens made from the test powder (DCT), as themathematical average of the three specimens, calculated to

42、thenearest 0.01 %, including the sign of plus (+) for growth andminus () for shrinkage.10.1.2 Report the comparative dimensional change betweenthe test powder and the reference powder (DC), as themathematical difference between the average absolute dimen-sional change from die size for the three spe

43、cimens made fromthe test powder and those from the reference powder as apercent to the nearest 0.01 %, including the sign of (+) or ()to indicate direction of the deviation.NOTE 1If the % dimensional change is divided by 100, the resultsthen will be expressed in in/in (mm/mm) units.10.1.3 Report the

44、 green density to the nearest 0.01 g/cm3asthe average density of the three test specimens (and the threereference specimens, if used).10.2 An alternative reporting method may be to graph thedimensional change as a function of the green density using theresults obtained at a minimum of three data poi

45、nts.10.3 The following supplementary information should alsobe 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 mixture used, ifother than elemental powder was being tested,

46、10.3.3 Type, brand and percent of the admixed lubricant (ifused) and the mixing procedure or details of die-wall lubrica-tion method (if used),10.3.4 Compacting pressure,10.3.5 Sintering temperature,10.3.6 Sintering time, defined as the elapsed time that thetest specimen is within 6 15 F (6 8 C) of

47、the stated sinteringtemperature for iron-base and 6 10 F (6 5 C) for copper-base powders,10.3.7 Furnace atmosphere,10.3.8 Cooling rate, and10.3.9 The absolute dimensional change of the referencepowder (if used).11. Precision and Bias11.1 Precision An inter-laboratory study (ILS) to deter-mine the re

48、peatability and reproducibility of the procedure inthis test method is under consideration by subcommitteeB09.02 and will be available in or before 2013.11.2 BiasNo information can be presented on the bias ofthe procedure in Test Method B 610 for measuring Dimen-sional Change because no material hav

49、ing an accepted refer-ence value is available.B61008312. Keywords12.1 absolute; dimensional change; compacting; compara-tive dimensional change; due size; metal powders; sinteringSUMMARY OF CHANGESSubcommittee B09.02 has identified the location of selected changes to this standard since the last issue(B610-00), that may impact the use of this test method(1) The title has been changed to more closely specify the use.(2) The Scope has been rewritten to cover “Purpose” and“Technique” per Blue Book.(3) Figure 1, The Test Specimen drawing, has been replaced bya referen