Rapid austenitisation as a method of martensitic steels toughening

摘要

On the selected industrial low alloyed steels the influence of heterogeneous martensitic microstructures produced by rapid austenitising of the initial ferritic-carbidic mixture with following quenching and low temperature tempering on strengthand fracture properties was investigated.In comparison to homogeneous martensite, the low carbon martensite containing the remainders of un-dissolved cementite particles exhibits a substantial increase in fracture toughness and a slight decrease of strength properties. The martensite containingmicro-regions with increased content of carbide forming elements shows the increase of fracture toughness without greater loss of strength. Phenomena observed are quantitatively on level comparable with alloying steel by 1.4% Ni.