Abstract
Hot work die steels have been lately used for structural materials of airplanes and reported that they showed superior results for high temperature services. DAC and DBC which contains 5% Cr are produced in Hitachi Metal Industries Ltd. as die steels for die casting. And therewith the writers studied on quenched and tempered hardness due to different heat treatment, mechanical properties at high temperature strength and oxidation resistance of these steels, for the purpose of inspecting their adaptability for heat resisting uses. It was concluded that both DAC and DBC showed good properties as heat-resisting steel at available temperature below about 600°C.
