Research and application progress in ultra-high strength stainless steel for aircraft landing gear

Abstract

Based on the design concept of aircraft landing gear, the recent achievements in research and development on both ultra-high strength steels and ultra-high strength stainless steels (UHSSS) for the landing gear in aircraft were reviewed. The composition, microstructure and mechanical properties of typical commercial UHSSS grades that were produced and used were also summarized. It was then proposed that the future research on UHSSS with the improved combination of strength and toughness should focus on designing both composition and processes of new UHSSS grades by using the up-to-date material thermodynamic and kinetic calculations, particular attention should be paid to microstructural designing on either high density coherent or multi-type nanosized precipitation and the deliberate tailoring of retained austenite with enhanced mechanical stability for toughening; both of them could contribute to the strengthening and toughening of UHSSS. Finally, the updated hot working technology was put forward, the isothermal multi-direction forging, which could significantly improve the comprehensive mechanical properties of UHSSS.

Keywords

• ultra-high strength stainless steel
• precipitation
• strengthening mechanism
• retained aus-tenite
• manufacturing process