ASTM A839-15(2023) PDF

ABSTRACT This specification covers parts produced from pressing and sintering of iron-phosphorus powders. The specification does not cover parts produced by metal injection molding. These parts are used in magnetic applications requiring higher permeability and electrical resistivity and lower coercive field strength than routinely attainable in parts produced from unalloyed iron powder. Two powder types are covered: Type I containing nominally 0.45% phosphorus, and Type II containing nominally 0.8% phosphorus. Apart from chemistry, parts produced to this specification shall have a minimum sintered density and maximum allowable coercive field strength. The minimum sintered density shall be 6.8 g/cm3 (6800 kg/m3) in the magnetically critical section of the part. Three grades with increasing maximum allowable coercive field strength are defined for each powder type. Detailed appendices showing the effect of sintering conditions on the magnetic and mechanical properties of parts made from both powders are included in this specification. SCOPE 1.1 This specification covers parts produced from iron-phosphorus powder metallurgy materials. These parts are used in magnetic applications requiring higher permeability and electrical resistivity and lower coercive field strength than attainable routinely from parts produced from iron powder. 1.2 Two powder types are covered; Type I containing nominally 0.45 wt.% phosphorus, and Type II containing nominally 0.8 wt.% phosphorus. 1.3 This specification deals with powder metallurgy parts in the sintered or annealed condition. Should the sintered parts be subjected to any secondary operation that causes mechanical strain, such as machining or sizing, they should be resintered or annealed. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to customary (cgs-emu and inch-pound) units, which 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.