Effect of double quenching process on Microstructure and Properties of 20CrMoH Alloy Steel

Abstract

This article investigates the influence of dual quenching process quenching temperature on the microstructure, hardness, and mechanical properties of 20CrMoH alloy steel through optical metallographic microscopy, Rockwell hardness tester, and universal mechanical testing machine. The results indicate that during the second quenching in the temperature range of 780-880 °C, with the increase of quenching temperature, the tensile strength of 20CrMoH steel shows a rapid increase trend, from 1250MPa to 1550MPa. At this time, the matrix structure gradually evolves from ferrite + bainite structure to bainite + martensite, which is also the main factor for its rapid increase in tensile strength; When the quenching temperature rises to above 850 °C, the influence of quenching temperature on the tensile strength decreases, and the tensile strength remains around 1550MPa. The secondary quenching temperature has little effect on the plasticity of the material. The overall reduction and elongation of the section under different quenching temperature conditions are at a similar level, with a reduction rate of 9% -12% and a stable reduction rate of 50% -60%, indicating good mechanical properties.