Abstract: Taking the forging module of 3Cr2NiMo die steel as the research object, the thermal physical parameters of which were calculated by JMatPro software. And the heat treatment after forging was studied by means of numerical simulation using Deform-3D software, the test verification was made at last. The results show that, the cooling rate of the outer surface of the module is higher than that of the core during quenching. The martensite transformation from the core to the surface does not simultaneously occur and the microstructure distribution from the surface to the core after quenching is martensite, bainite and ferrite in turn. The equivalent stress distribution along thickness direction is more uniform, but there is stress concentration at the edge position. The distribution of hardness values is positively correlated with the martensite distribution, and the average hardness value of the surface is 34.86 HRC. Meanwhile, the average thickness of martensite layer is 45 mm and the average hardness of surface is 36.23 HRC by the test verification. The error results between simulation and test are less than 10%, which has good accuracy.

Key words: 3Cr2NiMo die steel, heat treatment after forging, numerical simulation, microstructure, hardness testing