18.10.2004 Pressing & Sintering

Processing Conditions for High Strength PM Steels Alloyed with Chromium

PM2004, in Vienna, Austria. Authors: Sigurd Berg, Barbara Maroli.  Increased mechanical properties of sintered steels are the major factor for the introduction of PM components as substitute for wrought steels. Materials based on grades pre-alloyed with chromium have proved to be an attractive choice for the production of high performance PM parts. Already in the as-sintered condition materials alloyed with 1.5% res. 3% chromium achieve high strength compared to PM steels alloyed with up to 4% Ni. Further improved mechanical performance is achieved utilizing increased cooling rate i.e. sinter-hardening has been the break-through.  In this paper the influence of process conditions on the static and dynamic properties of materials prealloyed with chromium is presented and explained through their microstructure. Alternative process routes such as for example high temperature sintering followed by rapid cooling are shown to give outstanding performance such as yield strength of 1250Mpa and bending fatigue strength of 445MPa.