Abstract
Full investigation has never been performed with the effect of alloying elements on the hardenability and mechanical properties in a quench-and-tempered condition with commercial low-alloy steels, which are now widely utilized, and a more detailed study is desired which can be able to make clear such relationship in the case when the heat-treated article have a rather larger mass.
A comprehensive study was conducted to describe the effect of an increase of Ni, Cr, Mo and V contents, and a decrease of C content on hardenability and mechanical properties of Ni-Cr-Mo steel (SNCM 8: SAE 4340), and 11 melts were prepared to satisfy the test requirements. Special emphasis was laid on to examine the effects in the case of a larger mass.
Hardenability test was performed by examining microstructure and hardeness of the test specimens cooled at 4 different cooling rates (Fig. 1) using a specially designed control-cooling quenching apparatus.
