150 ton austenitic stainless steel ring manufactured using additive forging technology

Author: XU Bin , SUN Mingyue , LIU Hongwei , LI Dianzhong

On March 12, 2019, the austenitic stainless steel supporting ring with the world's largest diameter (15.6 meters) and the largest weight (150 tons) was successfully rolled in Jinan using the Additive Forging technology proposed by SYNL. This huge rolled ring is manufactured without welding, so it has good microstructural uniformity. It will be used in China's fourth-generation nuclear power plants. Its successful development will effectively protect China's nuclear industry equipment implementation. As the core component of a nuclear power plant, the support ring not only serves as the boundary and safety barrier of the pressure vessel, but also serves as the "backbone" of the entire vessels, thus bearing 7,000 tons of weight. In the past, the supporting rings were manufactured by multi-piece billet welding, which not only has a long manufacturing processing and high cost, but also has weak structural properties at the welding position, thereby laying a hidden safety hazard for the operation of nuclear power plant. After more than ten years of research, the research teams of IMR first proposed the idea of additive forging in the world. This technology uses multiple small-sized homogenized slabs as the basis material. By means of surface activation, vacuum sealing, and high-temperature deformation, the bonding interfaces are completely healed and its mechanical properties have no difference than that of the basis material. As homogenized slabs are used, the homogeneous large forging is obtained. Additive forging technology has been evaluated by many experts as a transformative and innovative technology in the field of large forging manufacturing. It has been widely used in hydropower, wind power, nuclear power and other fields. Additive forging technology has played an important role in promoting the rapid development of high-end equipment in China and ensuring the independence and controlling of the manufacturing of the core equipment. The research results were widely reported by CCTV News, People's Daily, and Science and Technology Daily.

Austenitic stainless steel supporting ring with a diameter of 15.6 meters