Experimental and Numerical Studies on Laser Quenching of 7CrSiMnMoV Steel

Laser quenching process tests of 7CrSiMnMoV steel at different laser power and scanning speeds were carried out. The effects of laser quenching on the microstructure of the hardened layer and heat affected zone were investigated, and the influence of laser process parameters on the distribution of martensite, residual austenite, and grain size were obtained. The results indicated that a large amount of martensite was formed in the hardened layer after laser quenching, and surface strengthening was realized under the combined action of grain refinement, phase transformation strengthening and aging strengthening. The effect of laser process parameters on the hardness of heat-treated specimens was investigated and the relationship equation between the hardened layer depth and laser energy density was obtained. A finite element analysis model of laser quenching process of 7CrSiMnMoV steel was established based on ABAQUS software to realize the simulation of the temperature field during the laser quenching process. The process optimization based on the response surface method was carried out, when the laser power, scanning speed and spot size are 1493.9 W, 2 mm/s and 20 mm × 3.9 mm respectively, the hardened layer depth of 0.829 mm can be obtained.