Recrystallization in type 304L stainless steel during friction stirring

Abstract

The recrystallization phenomenon during friction stirring (FS) of type 304L stainless steel was examined by orientation imaging microscopy. In the stir zone, a 〈100〉 fiber texture component containing a dominant orientation was observed from the center to the advancing side. Most grains having this dominant 〈100〉 fiber texture component contained a high density of dislocations in the as-processed condition. Post-processed heat treatment (HT) resulted in grain growth, twinning and a change in texture component in most grains having this 〈100〉 fiber component. Grains having a different orientation than the 〈100〉 fiber component, experienced grain growth and twinning without rotation of orientation during HT. From these results, it was deduced that friction stir processed 304L stainless steel partially underwent static recrystallization following dynamic recrystallization during FS.