Dissolution of carbon in Cr-prealloyed PM steels: effect of carbon source
Journal article, 2015

Modern water-atomised steel powder grades are characterised by the presence of two types of surface oxides: a thin iron oxide layer, covering more than 90% of the powder surface, and more thermodynamically stable particulate oxides. The development of inter-particle necks and carbon dissolution in the iron matrix both require efficient removal of the iron oxide layer. Hence, carbon reactivity strongly affects the surface oxide reduction that determines inter-particle neck development and carbon dissolution, and so microstructure development. An analysis is presented of the effect of three carbon sources – synthetic graphite, natural graphite and carbon black – on microstructure and inter-particle neck development in Cralloyed PM steels. Metallographic and fractographic studies indicate that the most significant property of the carbon sources affecting reactivity is the carbon powder size. Carbon black shows the highest reactivity at elevated temperatures but is fully inert at temperatures below 900uC.

graphite dissolution

powder metallurgy

chromium alloyed PM steels

graphite

carbothermal reduction

Author

Eduard Hryha

Chalmers, Materials and Manufacturing Technology, Surface and Microstructure Engineering

Lars Nyborg

Chalmers, Materials and Manufacturing Technology, Surface and Microstructure Engineering

Luigi Alzati

TIMCAL Ltd.

Powder Metallurgy

0032-5899 (ISSN)

Vol. 58 1 7-11

Driving Forces

Sustainable development

Areas of Advance

Production

Materials Science

Subject Categories

Materials Chemistry

Metallurgy and Metallic Materials

DOI

10.1179/0032589914Z.000000000191

More information

Created

10/7/2017