Advanced forming technologies for integrated metal components with extreme size and structure: State-of-the-art and perspectives

In aerospace, nuclear power, and new energy vehicles industries, utilizing integrated metal components with extreme sizes and/or structures is crucial for achieving significant weight-saving, performance-improvement, and excellent reliability. These components, made from metal sheets, rings, or tubes, exhibit characteristics like ultra-thin, ultra-thick, ultra-large, ultra-long, ultra-high ribs, and large variable diameters. During plastic deformation in metal forming processes, defects such as ruptures, wrinkles, excessive strain differences, and unexpected weak performance areas are likely to occur due to the intersection of multiple effects in different research disciplines, including materials science, processes, and mechanics of materials. Consequently, the smooth forming of integrated parts is difficult. It is the first time to review, summarize, and analyze the advancement of forming methods for producing integrated parts with extreme sizes and structures. The general academic ideas to change the process conditions and sequences to optimize stress state and improve plastic deformation ability for forming the components with extreme sizes/structures are introduced. Practical examples, discussed in detail in the paper, include the forming of (i) integrated ultra-thin and ultra-thick sheet components; (ii) integrated ultra-large size ring components with thin wall and high ribs; and (iii) integrated ultra-long tube components with large perimeter difference. Various plasticity technologies and process sequences have been developed. The key processes and applications of the technologies are discussed in detail, which achieve successful plastic forming of integrated components. This paper provides state-of-the-art and perspectives for the rapidly advancing material forming fields of key metal components for the next generation of equipment.