TWI

Friction stir welding (FSW) experiments were undertaken on type 304 austenitic stainless steel (18-20%Cr, 8-10.5%Ni) under various process conditions by changing the heat input, and the microstructure and mechanical properties of joints obtained at a welding speed of 1000 mm/min were investigated. I-groove butt welding was performed using a load control type FSW machine with Ar shielding gas for oxidation prevention. Welding speed was varied in the range 60-1000 mm/min and heat input was monitored by a K-type thermocouple. FSW joint characteristics were evaluated by visual inspection, cross-section macrostructure and microstructure observations, tensile tests and Vickers hardness profile measurements. The grain size and hardness of the stir zone are discussed.

6th International Symposium, 10-13 Oct 2006, Session 2A: FSW of High Temperature Alloys, Paper 04