Heat flow into friction stir welding tools

Abstract

Using experimental welding data and thermal modelling the transient heat losses into FSW tools were calculated. Heat loss into the tool enabled the welding efficiency to be determined. The body of this work covered the welding of two light alloys using solid steel tools. Finally the use of grooves in the tool to impede heat flow was investigated as a way of increasing welding efficiency. The work concludes that using solid tools the steady state heat loss into the tool is about 10% of the total heat generated; for short welds that start with a cold tool this can be higher. Grooves in the tool shank increase the thermal efficiency and stability of the welding process.