Analysis of service condition of large hot forging die and refabrication of die by bimetal-layer weld surfacing technology with a cobalt-based superalloy and a ferrous alloy

Large forming load at high temperature causes the occurrences of plastic deformation, wear, mechanical fatigue, and thermal fatigue in the large hot forging dies and resulted in their short service lives. In this study, temperature field, stress field, and wear condition of large hot forging die were predicted and evaluated by finite element modelling (FEM) analysis. Corroborated by the experimental results, analysis results demonstrated that failures mainly occurred in bridge, boss, and groove regions of the large hot forging dies. According to the analysis and experimental results, the failed large hot forging dies were refabricated by bimetal-layer weld surfacing technology with a cobalt-based superalloy (Co03) and a ferrous alloy (JXHC15). No failure was observed on these refabricated dies, after production of 25 pieces. In comparison with the conventional fabrication or prefabrication methods, this bimetal-layer weld surfacing technology reduced the fabrication cost, shortened the fabrication cycle, and elongated the service lives of large hot forging die effectively.