An experiment study on a novel constructive hot ring rolling process

Abstract

The traditional rolling process for large ring part is to forge a large ring blank from a large cast ingot firstly and then ring rolling it to a large ring. However, large ingots are more likely to produce casting defects such as voids and composition segregation. The casting defects will bring hereditation to the final ring product, especially for super-large ring whose dimeter is more than ten meters. In this paper, a novel constructive hot ring rolling method to manufacture the high performance large ring is proposed. In this process, ring blank units are forged by high-quality small ingots firstly. Then the ring blank units are assembled together to a large ring blank and surface welded along the unit interface. Finally, the large assembled ring blank is heated and ring rolled to a large seamless ring. To verify the feasibility of the constructive hot ring rolling process, an experiment of constructive hot ring rolling process was carried out in the laboratory condition. Two separated rings are machined firstly. Then cleaning the surface of the two rings and assembling them together. Follow on, the upper and lower interfaces of the assembled ring are welded in the surface areas. Finally, the ring blank is heated to high temperature and deformed by radial ring rolling. The microstructure status and mechanical properties of the forming ring are tested. It is found that the interface is healed after high temperature rolling. The tensile strength of the constructive rolling ring is close to the ring rolled from a seamless ring blank. The research work can provide a new idea for the manufacturing technology of high performance large ring.