A Study on Grade 1000MPa High Performance Steel Plate Processing by Direct Quenching

A 1000MPa grade steel plate for coal mining machinery equipment was studied in this paper. The ultra-high strength steel plate is processed by direct quenching after hot rolling plus tempering (DQ-T) to obtain high toughness and ductility. It has found that the tempering temperature has an important influence on the steel microstructure, precipitation behavior and the plate mechanical properties. At the lower tempering temperatures from 400 °C to 450 °C, the steel plate has a low toughness. When the tempering temperature is higher than 450 °C, the higher mechanical properties can be obtained due to the carbides precipitation, dislocation dissolution and carbide decomposition from residual austenite after quenching. The steel microstructure is comprised of tempered sorbite and bainite, in which sorbite plays an important role in obtaining premium microstructure.