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

Abstract

In this work the through hardenability and the influence of the heat treatment parameters (austenitizing
temperature, cooling parameter ? and tempering temperature) on the microstructure and the achievable
toughness level of Böhler M333 ISOPLAST are investigated. The results are compared to the standardized
tool steel grade DIN 1.2083. The investigations showed that the cooling parameter ? 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.