TWI

Conventional friction stir welding (FSW), hybrid FSW and thermal stir welding were evaluated and compared for the joining of a nickel-based superalloy Haynes 230. Welds were made in Haynes 230 NiCrW alloy (20-24%Cr, 13-15%W, 6.4 mm thickness), an industrial-grade heat-resistant alloy. Each of the processes is outlined. Various induction temperatures were evaluated for provision of heat to soften the material without degradation and whilst ensuring survivability of the rod. Stir rod tool materials used were La-W, swagged 25%Re-W, extruded 25%Re-W and 25%Re-W with Hf-C. The microstructure, yield strength, hardness and grain distribution were investigated. The three solid-state welding processes are discussed together with the metallographic results from the trials.

8th International Symposium, 18-20 May 2010, Session 8B: Nickel and Stainless Steel, Paper 01