Forging limit of a novel high-speed-steel cold work roll based on ductile fracture criteria by finite element model

In this study, the temperature field, stress field and strain field of a novel high-speed-steel (HSS) cold work roll during forging process were simulated by Deform-3D software on the basis of rigid–viscoplastic finite element (FE) model. The effects of forging temperature, speed and position on the maximum effective stress (MES) of the billet, maximum reduction (MR) and maximum Z load (MZL) of the anvil before cracking were analyzed based on Normalized C&L ductile fracture criterion. Finally, the forging limit diagram was drawn. The results show that seven passes are carried out during the forging process. The temperature field, stress field and strain field of the forging zone distribute un-uniformly, but the billet has been penetrated before cracking. The MES and MR are insensitive to the forging speed, and the MZL is in the safe range consistently at 1000–1140 °C. When the surface temperature of the billet is below 1000 °C, some parameters have exceeded the measured limit, which indicates that it is not suitable to go on forging.