【国外标准】 Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle

5.1 The volume of a complex shaped PM part cannot be measured accurately using micrometers or calipers. Since density is mass per unit volume, a precise method for measuring the volume is needed. Archimedes’ principle may be used to calculate the volume of water displaced by an immersed object. For this to be applicable to PM materials that contain surface connected porosity, the surface pores are sealed by oil impregnation or some other means.5.2 The green density of compacted parts or test pieces is normally determined to assist during press set-up, or for quality control purposes. It is also used for determining the compressibility of base powders, mixed powders, and premixes.5.3 The sintered density of sintered PM parts and sintered PM test specimens is used as a quality control measure.5.4 The impregnated density of sintered bearings is normally measured for quality control purposes as bearings are generally supplied and used oil-impregnated.1.1 This standard describes a method for measuring the density of powder metallurgy products that usually have surface-connected porosity.1.2 The density of impermeable PM materials, those materials that do not gain mass when immersed in water, may be determined using Test Method B311.1.3 The current method is applicable to green compacts, sintered parts, and green and sintered test specimens.1.4 With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic centimetre (g/cm3) and gram (g) units is the long-standing industry practice, the values in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.