1、Designation: B311 08B311 13Standard Test Method forDensity of Powder Metallurgy (PM) Materials ContainingLess Than Two Percent Porosity1This standard is issued under the fixed designation B311; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test met
3、hod covers the determination of density for powder metallurgy (PM) materials containing less than two percentporosity and for cemented carbides. This test method is based on the water displacement method.NOTE 1A test specimen that gains mass when immersed in water indicates the specimen contains sur
4、face-connected porosity. Unsealed surfaceporosity will absorb water and cause density values higher than the true value. This test method is not applicable if this problem occurs.1.2 With the exception of density values, the values for density and the mass used to determine density, for which the g/
5、cmuseof the gram per cubic centimeter (g/cm3 unit ) and gram (g) units is the long-standing industry standard,practice, the values statedin SI units are to be regarded as the standard. Values in inch-pound units are shown in parentheses and result from conversion inaccordance with IEEE/ASTM Standard
6、 SI 10.standard.1.3 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 applicability of regulatorylimitations prior to use.2
7、. Referenced Documents2.1 ASTM Standards:2B243 Terminology of Powder MetallurgyE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test MethodE456 Terminology Relating to Quality and Statistics2.2 IEEE/ASTM Standard:SI 10 American National Standard for Use of the In
8、ternational System of Units (SI): The Modern Metric System2.3 ISO Standard:3369 Impermeable Sintered Metal Materials and HardmetalsDetermination of Density3NOTE 2The water density table in ISO 3369 differs from the table contained in this test method.3. Terminology3.1 Definitions of powder metallurg
9、y (PM) terms can be found in Terminology B243. Additional descriptive material isavailable in the Related Material section of Vol. 02.05 of the Annual Book of ASTM Standards.4. Summary of Test Method4.1 Using an analytical balance, the test specimen is first weighed in air and then in water. The den
10、sity is determined bycalculation using Archimedes principle.5. Significance and Use5.1 For PM materials containing less than two percent porosity, a density measurement may be used to determine if the part hasbeen densified, either overall or in a critical region, to the degree required for the inte
11、nded application. Density alone cannot beused for evaluating the degree of densification because chemical composition and heat treatment affect the pore-free density.1 This test method is under the jurisdiction ofASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct respons
12、ibility of Subcommittee B09.11on Near Full Density Powder Metallurgy Materials.Current edition approved Dec. 1, 2008April 1, 2013. Published January 2009June 2013. Originally approved in 1956 . 1956. Last previous edition approved in 20022008as B311 93B311 08.(2002)1 . DOI: 10.1520/B0311-08.10.1520/
13、B0311-13.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intende
14、d 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 adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current
15、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 International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 For cemented carbides, a densit
16、y measurement is normally used to determine if there is any significant deviation incomposition of the carbide grade. For straight tungsten carbide-cobalt grades, the relationship is straightforward. For complexcarbide grades (for example, grades containing tantalum carbide or titanium carbide, or b
17、oth, in addition to tungstencarbide-cobalt), the situation is more complicated. If the measured density is beyond the specified limits, the composition is outsideof the specified limits. A measured density within the specified limits does not ensure correct composition; compensation betweentwo or mo
18、re constituents could result in the expected density with the wrong composition. Density alone cannot be used forevaluating a cemented carbide grade.6. Apparatus6.1 Analytical Balanceprecision single-pan analytical balance that will permit readings within 0.01 %0.01% of the testspecimen mass. The an
19、alytical balance shall be supported in a manner to eliminate mechanical vibrations and be shielded fromair drafts. See Table 1.6.2 Weighing LiquidDistilled or deionized water to which 0.05 to 0.1 volume percent of a wetting agent has been added toreduce the effects of surface tension.NOTE 2Degassing
20、 the water by evacuation, boiling, or ultrasonic agitation helps to prevent air bubbles from collecting on the test specimen andspecimen support when immersed in water.6.3 Water ContainerA glass beaker or other suitable transparent container should be used to contain the water.NOTE 3A transparent co
21、ntainer makes it easier to see air bubbles adhering to the test specimen and specimen support when immersed in water.NOTE 4For the most precise density determination, the water container should be of a size that the level of the water does not rise more than 2.5mm (0.10 in.) when the test specimen i
22、s lowered into the water.6.4 Test Specimen Support for Weighing in WaterTwo typical arrangements are shown in Fig. 1. The suspension wire may betwisted around the test specimen or the test specimen may be supported in a wire basket that is attached to the suspension wire.For either arrangement, a si
23、ngle corrosion resistant wirefor example, austenitic stainless steel, copper, nichromeshall be usedfor the basket and suspension wire. For the maximum recommended diameter of suspension wire to be used for various massranges see Table 2.NOTE 5For the most precise density determinations, it is import
24、ant that the mass and volume of all supporting wires immersed in water be minimized.6.5 ThermometerA thermometer with an accuracy of0.2 C to measure the temperature of the water.7. Preparation of Test Specimens7.1 A complete part or a section of a part may be used for the test specimen. For the high
25、est precision, the test specimen shallhave a minimum mass of 5.0 g. If less precision can be tolerated, several test specimens may be used to reach the minimum mass,provided each test specimen has a mass of not less than 1.0 g.7.2 All test specimen surfaces shall be thoroughly cleaned of all adherin
26、g foreign materials, such as, dirt, grease, oil, oxide scale,metal powders or assembly materials. For cut specimens, care must be used to avoid rough surfaces to which an air bubble canadhere. A100-grit A 100-grit sanding or abrasive grinding is recommended to remove all rough surfaces.8. Procedure8
27、.1 Weigh the test specimen in air using an analytical balance. This is mass A. This and all subsequent weighings shall be to0.01% of the test specimen mass.It is important that the test specimen, analytical balance and surrounding air be at a uniform temperature when the weighing isperformed.NOTE 6F
28、or improved reproducibility, the analytical balance should be periodically calibrated with a standard mass that is approximately equal to thetest specimen mass.8.2 Support the container of water over the pan of the balance using a suitable bridge as shown in Fig. 2. The container of watermay also be
29、 supported below the balance for weighing larger specimens if the balance has a lower beam hook for this purpose.See Fig. 2b. If this arrangement is used, it is important to shield the suspension wire between the container of water and the bottomof the balance from air drafts.TABLE 1 Balance Sensiti
30、vityMass, g Balance Sensitivity, gless than 10 0.000110 to less than 100 0.001100 to less than 1000 0.011000 to less than 10 000 0.1B311 1328.3 Suspend the test specimen support with the test specimen from the beam hook of the balance. The water should cover anywire twists and the specimen support b
31、asket by at least 6 mm (14 in.) to minimize the effect of surface tension forces on theweighing. Care should be taken to ensure that the test specimen and specimen support hang freely from the balance beam hook,are free of air bubbles where immersed in the water and are at the same temperature as th
32、e water and balance. Care should alsobe taken to ensure the surface of the water is free of dust particles.8.4 Weigh the test specimen and specimen support immersed in water. This is mass B.8.5 Remove the test specimen. Weigh the test specimen support immersed in water at the same depth as before. T
33、his is massC. Care should be taken to ensure that the suspension support is free of air bubbles and that the suspension wire is not immersedbelow its normal hanging depth as a change in depth will change the measured mass.NOTE 7Some balances are capable of being tared. This automatically removes the
34、 necessity of reweighing the specimen support every time. In thiscase, tare the specimen support alone, immersed in water to the same depth as with the specimen, before weighing the specimen support and specimenimmersed in water. The mass of the specimen support and specimen immersed in water is mas
35、s F, which replaces mass B minusmass C.FIG. 1 Methods for Holding the Test Specimen When Weighing in WaterTABLE 2 Maximum Recommended Wire DiameterMass, g Wire Diameter, mm (in.)Mass, g Wire Diameter, mmless than 50 0.12 (0.005)less than 50 0.1250 to less than 200 0.25 (0.010)50 to less than 200 0.2
36、5200 to less than 600 0.40 (0.015)200 to less than 600 0.40600 and greater 0.50 (0.020)600 and greater 0.50B311 1338.6 Measure the temperature of the water to the nearest0.5 C and record its density E, at that temperature, fromTable 3.9. Calculation9.1 Calculate the density as follows:Density5D 5Mas
37、s/Volume (1)D 5A/A 2B 2C!#E (2)D 5A 3E!/A 2B1C! 5A 3E!/A 2F! (3)where:D = density of test specimen, g/cm3,A = mass of test specimen in air, g,B = apparent mass of test specimen and specimen support in water, g,C = mass of specimen support immersed in water, g,F = mass of test specimen in water with
38、mass of specimen support tared, g, andE = density of water in g/cm3.where:D = density of test specimen, g/cm3,A = mass of test specimen in air, g,B = apparent mass of test specimen and specimen support in water, g,C = mass of specimen support immersed in water, g,F = mass of test specimen in water w
39、ith mass of specimen support tared, g, andFIG. 2 Methods for Weighing in WaterB311 134E = density of water in g/cm3.10. Report10.1 Report the density rounded to the nearest 0.01 g/cm3.11. Precision and Bias11.1 Interlaboratory Test ProgramThe following precision data were developed using the procedu
40、res contained in Aninterlaboratory study of the Density Test Method B311 86. The results of the interlaboratory study that was conductedwas runin 1990. Eleven test laboratories tested eighteen different materials. The design of the study followed Practice E691 aresummarized in a and a within-between
41、 analysis of the data are given in Research Report RR:B09-10143. An interlaboratory studyis planned using the procedures in this revised test method.11.2 Test ResultsThe precision information presented herein has been calculated for the results from eleven laboratories andfor duplicate results for e
42、ach of eighteen materials tested.11.3 Precision:11.3.1 95% Repeatability Limit (within a laboratory)The within-laboratory repeatability limit, r, as defined by TerminologyE456, is estimated to be 0.025 g/cm3. At the 95% confidence level, duplicate density test results from the same laboratory should
43、not be considered different unless they differ by more than r.11.3.2 95% Reproducibility Limit (between laboratories)The between laboratories reproducibility limit, R, as defined byTerminology E456, is estimated to be 0.03 g/cm3 for test specimens with a mass of greater than 5 g. For test specimens
44、with amass of from 1 to 5 g it is estimated to be 0.05 g/cm3. At the 95% confidence level, duplicate density test results from differentlaboratories should not be considered different unless they differ by more than R.11.4 BiasThere is no estimate of bias No information can be presented on the bias
45、of the procedure in Test Method B311 formeasuring Density because no material having an accepted reference value is available.11.5 Measurement UncertaintyThe precision of Test Method B311 shall be considered by those performing the test whenreporting Density test results.12. Keywords12.1 cemented ca
46、rbides; density; hard metals; metal injection molded (MIM) parts; powder metallurgy (PM); powder forged(PF) parts; powder metallurgy3 Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:B09-1014. Contact ASTM CustomerService at serv
47、iceastm.org.TABLE 3 Density of Air-Free WaterATemperature (C) Density (g/cm3)18.0 0.998618.5 0.998519.0 0.998419.5 0.998320.0 0.998220.5 0.998121.0 0.998021.5 0.997922.0 0.997822.5 0.997623.0 0.997523.5 0.997424.0 0.997324.5 0.997225.0 0.997025.5 0.996926.0 0.996826.5 0.996627.0 0.996527.5 0.996428.
48、0 0.996228.5 0.996129.0 0.995929.5 0.995830.0 0.9956AMetrological Handbook 145,“ Quality “Quality Assurance for Measurements,”National Institute of Standards and Technology, 1990, p. 9.10.B311 135SUMMARY OF CHANGESCommittee B09 has identified the location of selected changes to this standard since t
49、he last issue(B311 93B311 08(2002) 1 ) that may impact the use of this standard. (Approved April 1, 2013.)(1) Terminology section added (Section 3) and reference made to Changed the wording of the statement on units B243in Section2.1.1.2.(2) Deleted reference to “thermistor” thermometer IEEE/ASTM SI 10 in Section 6.5.2.2.(3) Deleted NOTE 7 (duplicate weighings)reference to ISO 3369 in Section 2.3.(4) Included a reference to the Research Report on file atASTM Headquarters (RR B09-1014). Deleted the inch-pound units fromTable 2.(5) N
