Dissolution of different graphite grades during sintering of PM steels

• Published in: Materials chemistry and physics Vol. 67; no. 1; pp. 72 - 77
• Main Authors: Danninger, Herbert, Frauendienst, Gerald, Streb, Klaus-Dieter, Ratzi, Raimund
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01-01-2001; Elsevier
• Subjects: Applied sciences; Carbon dissolution; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Graphite; Materials science; Materials synthesis; materials processing; Metals. Metallurgy; Physics; Powder processing: powder metallurgy, compaction, sintering, mechanical alloying, and granulation; Graphite; Carbon dissolution; DTA; Plastic fatigue; Metal powder; Sintering; Carbon steels; Sintered steel; Steels; Experimental study; Powder metallurgy; Dissolution; TGA
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/S0254-0584(00)00422-3

The dissolution behaviour of graphite during sintering of Fe–0.8%C and the resulting properties were studied using standard high quality natural graphite and an artificial graphite grade recently developed for ferrous powder metallurgy. Sintering was done in high purity N
2 atmosphere for 60
min, the temperature being varied. It showed that dissolution of carbon takes place mainly in the isothermal temperature range 750–950°C, for the artificial graphite the maximum dissolution rate being observed at a temperature about 50° lower than for the natural graphite. This also affects the properties, especially the hardness, of the specimens sintered in this temperature range while at standard sintering temperatures of about 1120°C both graphite grades yield well comparable results. Therefore, selection of the graphite grade seems to be important especially for pre-sintering of specimens prior to further treatment, dissolution of the graphite increasing the hardness but also improving the inter-particle strength.