Influence of welding speed on microstructure formation in friction-stir-welded 304 austenitic stainless steels

Abstract

The influence of welding speed on the joint microstructures of an austenitic stainless steel (ASS) produced by friction stir welding (FSW) was investigated. The FSW process was conducted using a rotational speed of 400 r/min and welding speeds of 50 and 150 mm/min. The study was carried out using electron backscattered diffraction (EBSD) technique in different regions of the resultant stir zones (SZs). The results show that the texture of the advancing side (AS) was mainly composed of C {001} ❬110❭ and cube {001} ❬100❭ texture components along with partial ${\rm B}/\bar{{\rm B}}$ {112}❬110❭ component. Moving from the AS toward the center and the retreating side (RS), the cube texture component disappeared and the A*₁ /A*₂ {111} ❬112❭ component developed and predominated the other components. Higher welding speed greatly affected and decreased the intensity of the textures in the resultant SZs. Moreover, higher welding speed (lower heat input) resulted in lower frequency of cube texture in the AS.

Keywords

friction stir welding / stainless steels / welding speed / dynamic recovery / shear texture / continuous dynamic recrystallization

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