10.6.2003 Pressing & Sintering

Sinter-Hardening and Heat Treatment of Materials based on Astaloy CrM

PM²TEC 2003, in Las Vegas, USA. Authors: Barbara Maroli, Sigurd Berg, Peter Thorne, Ulf Engström. Increased mechanical property of sintered steels is the major factor for the introduction of PM components as substitute for wrought steels. Materials based on the newly developed grades prealloyed with chromium, Astaloy CrM and Astaloy CrL, reach, depending on processing conditions, static and dynamic properties comparable to those of conventional fully dense steels.  In this paper the influence of the sintering temperature combined with increased post-sintering cooling rate or heat treatments such as low pressure carburizing, on the static and dynamic properties of materials based on Astaloy CrM is presented. If high temperature is followed by rapid cooling a tensile strength of 1400 MPa (200 ksi) is achieved, while by combining high temperature sintering with low pressure carburizing a fatigue limit over 500 MPa (72 ksi) can be obtained. A study of the dimensional stability of Astaloy CrM gears manufactured under production condition is also discussed.