INFLUENCE OF HEAT TREATMENT ON THE MICROSTRUCTURE AND TOUGHNESS OF BOHLER M333 ISOPLAST STEEL

摘要

In this work the through hardenability and the influence of the heat treatment parameters (austenitizing temperature, cooling parameter lambda and tempering temperature) on the microstructure and the achievable toughness level of Bohler M333 ISOPLAST are investigated. The results are compared to the standardized tool steel grade DIN 1.2083. The investigations showed that the cooling parameter lambda has a strong influence on the impact toughness of M333 ISOPLAST plastic mould steel. The toughness is reduced by pro-eutectoid precipitates and not by a lack of through hardenability. Furthermore, it was found out that depending on the cross section of the moulds appropriate heat treatments lead to a good combination of hardness and toughness.