Toughness and toughening of the high speed steel

This paper deals with the effect of heat treatment regimes on K1c and K1d of 6-5-4-2 (M 2) high speed steel. A toughening mechanism has been developed on the basis of the assumption that cracks in high speed steels are likely to propagate in a ductile manner. The toughness of high speed steels with a certain amount of carbides can be improved by increasing the distance between carbides, avoiding the formation of coarse or aggregated carbides and preventing carbides from precipitating at grain boundaries. This paper indicates that it is reasonable to evaluate the toughness of high speed steels by comparing their K1d values.