Abstract: To develop heavy equipment, optimize the hot working process of high alloy steel forging, and control the microstructure and properties of it, the surface cracking behaviors of flanged and cylindrical specimens of a high alloy steel are investigated by numerical simulation, and the simulation results are verified in combination of physical simulation and microstructure observation. The cracking tendency of flanged and cylindrical specimen is analyzed. The dependence of surface cracking tendency during the hot deformation on the shape dimensions of the flanged specimen is discussed. The results show that, under the same hot deformation parameter condition, the surface crack is more susceptible to appear at the half height of the flanged specimen than cylindrical specimen; the surface cracking behavior of the high alloy steel during hot forging can be well predicted by using the combination of fracture criterion, suitable for cold deformation, and dynamic microstructure change; adoption of the size-optimized flanged specimen can conveniently obtain the surface cracking behavior of high alloy steel during hot forging.

Key words: Cracking, Dynamic recrystallization, Forging, Microstructure, Simulation