Optimised sintering route for cold work tool steels

Two different powder metallurgy cold work tool steels, D7 and a nickel alloyed D7 modification, were compacted to full density by utilisation of super solidus liquid phase sintering in vacuum and nitrogen atmospheres. The experiments were carried out with respect to the fabrication of wear resistant metal matrix composites. These materials exhibit a higher durability than cast materials and are increasingly used in the mineral and mining industry. In the present paper, sintering exhibits a more cost effective processing of these materials compared with hot isostatic pressing. The experiments were supported by thermodynamic calculations with Thermo-Calc. Significant differences of the sintering behaviour in vacuum and nitrogen atmospheres were detected. Full density could be obtained at a sintering temperature as low as 1210°C.