Friction Stir Welding of Ultrafine Grained Interstitial Free Steels

Abstract

Friction stir welding (FSW) was applied to ultra low-carbon interstitial free steels with mean grain sizes ranging from 0.7 μm, prepared by accumulative roll-bonding, to 27 μm. The steel with the intermediate grain size (1.8 μm) is most preferable for obtaining the highest hardness in the stir zone with the smallest grain size.