Abstract: Aiming to solve some process pain points encountered during the heat treatment process of Cr12MoV steel molds with different shapes, differences in laser quenching processes were investigated for the large area smooth surface and small area convex dots on such molds by using the Cr12MoV steel tested blocks and fiber laser equipment. The results show that the two processes have similarities and differences. The common point is that the depth and hardness of the hardened layer are directly proportional to the laser heating temperature and inversely proportional to the scanning speed, while it is possible to cause overheating or even micro melting of the surface layer if the temperature is too high or the scanning speed is too slow. The difference is that, caused by the differences in heated areas and shape, their process parameters may vary significantly. The most suitable process parameters for the small area convex dots are laser heating temperature of 960 ℃ and scanning speed of 250 mm/min, while for the large area smooth surface are 1180 ℃ and 250 mm/min, and the occurrence of soft band phenomenon is inevitable for the latter case. Such research results are helpful for process personnel to choose appropriate process parameters according to actual needs when laser surface quenching is applied to molds with different shapes.

Key words: Cr12MoV steel, small area convex dots, large area smooth surface, laser quenching, microstructure, microhardness