Microstructural evolution in 42CrMo steel during compression at elevated temperatures

In order to study the workability and to optimize the processing parameters for 42CrMo steel hot forming, the hot compressive tests of 42CrMo steel were performed in the temperature range of (850–1150) °C at strain rates of (0.01–50) s− 1 and deformation degrees of (10–60)% on Gleeble-1500 thermo-simulation machine. The effects of processing parameters, including the strain rate, forming temperature and deformation degree, on the microstructures of 42CrMo steel were investigated by metallurgical analysis. The results show that the average grain size of the deformed 42CrMo steel increases with the forming temperature and decreases with the deformation degree and strain rate. In a word, the grain size of hot compressive 42CrMo steel is dependent on the forming temperature, strain and strain rate, also on Zener–Hollomon parameter.