Computer aided design of PM high speed steels for vacuum and nitrogen atmospheres

Abstract

Computer aided alloy design has been used to develop new highly sinterable alloys in order to fulfil the requirements for robust processing of powder metallurgy high speed steels. Three alloys (M35IG, AR-K2 and M42HVIG) have been designed and subsequently analysed in terms of the expected sintering behaviour, atmosphere interaction and microstructural features. Predicted optimum sintering temperatures are 1200°C for the vacuum sintered M35IG alloy and 1150°C for the AR-K2 and M42HVIG alloys sintered under a 90N₂+9H₂+ 1CH₄ atmosphere. On the other hand, the expected sintering windows exceed 10°C for all the alloys and the sensitivity to small compositional changes has been minimised guaranteeing the robust processing requirements. Additionally, sintering temperatures of 1150°C allow processing in continuous belt furnaces with the inherent interest for the industrial environment. Thermo-Calc software and the TC-Fe2000 database have been used to obtain the different calculations on the multicomponent systems.