Research on gradient additive remanufacturing of ultra-large hot forging die based on automatic wire arc additive manufacturing technology

In this paper, an automatic WAAM technology is proposed to realize the gradient additive remanufacturing of ultra-large hot forging dies. Firstly, a vertical additive manufacturing strategy and a normal additive manufacturing strategy are proposed to meet different additive manufacturing demands. Secondly, the basic principle of layering design of ultra-large hot forging dies is developed, and the wear resistance of Ni-based, Co-based, and Fe-based alloys at room temperature and high temperature is analyzed. The Co-based alloy has the best high-temperature wear resistance, which can be used on the surface of the hot forging die to strengthen the die. In order to control the forming quality of additive manufacturing, the relationship between welding parameters and weld shape was discussed, and the reverse system of welding process parameters was built. Finally, a typical aviation ultra-large hot forging die is selected as the research object. According to different stress and temperature distribution in different regions of the ultra-large hot forging die in service, materials with different properties are used in corresponding regions to improve the service life of the die, reduce the remanufacturing costs, and improve the remanufacturing efficiency. The experimental results show that the service life of the hot forging dies repaired by the automatic gradient function WAAM technology is significantly increased, the material is reduced by more than 50%, and the production efficiency is increased by more than 50%.