Analysis of heat treatment parameters on the properties of selected tool steels M390 and M398 produced with powder metallurgy

This paper deals with the comparison of two tool steels M390 and M398 produced by powder metallurgy MICROCLEAN type. The primary use steel is in plastics industry to produce screws for injection moulding machines. main purpose analyze hardness after different stages heat treatment. first part article evaluates hardening, which was performed using a hardening dilatometer DIL805A. A total 8 controlled cooling measurements were performed, both types powdered steels, from maximum rate 100 °C/s minimum 0.01 ° C/s. Based on results set samples dilatometer, optimal time evaluated achieve highest materials. used treat second that had undergone quenching process selected group quenched -78 °C. Freezing reduce amount residual austenite. Before measuring hardness, tempered at temperatures 200, 400, 600 °C 2x2h. measured values then compared data manufacturer BÖHLER.