Study on Direct Quenching and Tempering Process of 1000MPa Grade Low Alloy High Strength Steel

The direct quenching and tempering process of 1000MPa low alloy high strength steel had been studied in this paper. When the tempering temperatures were between 550°C and 610°C after direct quenching, carbides began to precipitate in the test steel, and the main microstructure were tempered martensite. When tempering temperatures were between 640°C and 670°C, the recovery stage of martensite lath basically ended and recrystallization began. The precipitated carbides grew up and the microstructure were mainly tempered sorbite. The results showed that the optimum tempering temperature range of the test steel was 610°C~640 °C. The yield strength and tensile strength of the test steel were greater than 1000MPa, and the comprehensive properties of the test steel were better. It provided guidance for the production of 1000MPa high strength steel by direct quenching and tempering process in industry.