Hardenability testing of steels when gas quenching is applied

Abstract

AbstractThe common test for assessing hardenability is the standardised Jominy end-quench test according to ASTM-A255 or DIN-EN 50191. This test is applied essentially for non-alloyed and low alloyed structural steels, when quenched in liquid quenchants, but it is not applicable for high alloyed (air hardening) steels, because the cooling rate at the opposite end of the Jominy specimen is higher than the critical cooling rate of those steels. Today there is no a standardised method to test and evaluate the hardenability of high alloyed steels. Nowadays, not only high alloyed steels, but also some low alloyed structural steels are quenched by high pressure gas quenching (HPGQ) in vacuum furnaces. Obviously there is need from one side to develop a standardised method for testing and evaluation of hardenability for high alloyed steels when they are gas quenched, and from the other side to establish a database for hardenability of low-alloyed structural steels when they are quenched in vacuum furnaces by HPGQ...