Heat-treated steels with optimized toughness

摘要

Compositions and methods of processing have been developed to optimize the impact toughness of heat-treated, low-alloy steels. The disclosed ranges of steel composition provide a lightly-tempered martensitic microstructure in which grain-refining precipitate forming elements such as titanium and aluminum are essentially absent and the content of iron/alloy carbides retained through the hardening operation is minimized through the application of an appropriate heat treatment wherein austenitizing takes place at temperatures of about 900 DEG C or above followed by quenching and moderate tempering at about 180 DEG C.