China National Machinery Industry Corporation (Sinomach) Heavy Equipment Develops 16.6-Ton Nickel-Based Cylinder Casting for 700°C Steam Turbine

en.Wedoany.com Reported - On October 10, the full-scale industrial trial piece of a 16.6-ton K317 nickel-based heat-resistant alloy cylinder casting for 700°C ultra-supercritical steam turbines, developed by Erzhong (Deyang) Heavy Equipment Co., Ltd. under Sinomach Heavy Equipment, passed on-site expert witness review. This casting is currently the largest industrial trial piece by mass among comparable 700°C ultra-supercritical steam turbine cylinder castings developed worldwide, and its routine performance testing has met the project's technical specifications. The Institute of Metal Research, Chinese Academy of Sciences, announced the related development progress on October 15.

This R&D task falls under the National Science and Technology Major Project "R&D and Application of Key New Materials" and is jointly undertaken by nine institutions, including the Institute of Metal Research, Chinese Academy of Sciences; Erzhong (Deyang) Heavy Equipment Co., Ltd.; and Dongfang Turbine Co., Ltd. of Dongfang Electric Corporation. The project focuses on the development of K317 nickel-based heat-resistant alloy and large castings for 700°C ultra-supercritical steam turbine cylinders, with Researcher Zhou Lanzhang from the High-Temperature Alloy Additive Manufacturing Research Group at the Institute of Metal Research, Chinese Academy of Sciences, serving as project leader.

After two years of joint efforts, the research team completed the compositional design of the K317 nickel-based heat-resistant alloy and its matching welding materials, and mastered the structural design and manufacturing processes for large cylinder castings. For large-tonnage alloy melting, the team achieved purification, homogenization, and precise compositional control of a 37-ton nickel-based alloy melt under non-vacuum conditions, forming a complete set of technologies for pouring, repair welding, and heat treatment of large castings.

The project also completed the development of manufacturing technology for HGH317 matching welding wire, incorporating the nickel-based heat-resistant alloy, casting forming process, and welding materials into a single R&D task. The full-scale cylinder casting prepared this time has completed routine performance testing and on-site expert review; subsequent engineering applications will target high-temperature pressure-bearing components of 700°C ultra-supercritical steam turbines.