Application of ultrafast heating and tempering to plate steel

Abstract

The microstructure and tensile properties were studied in a low-alloy steel plate treated under ultra-fast heating, quenching, and tempering. The microstructure after heat-treatments was predominantly martensite, with low fraction of bainite and ferrite. The tensile tests showed a 100 MPa improvement in strength and a doubling of the total elongation with the increase in heating rate. The tempering process considerably enhanced the ductility from 1–4% to up to 14% in the samples treated at fast heating rates..Furthermore, the work hardening capacity of ultra-fast heated steel was superior compared to steel treated under conventional quenching and tempering. The results suggest that the tempering stage after ultra-fast heat-treatments and quenching further improves the properties compared to the standard quenched and tempered condition.