Microstructural Evolution in 304 Austenitic Stainless Steel during Friction Stir Welding

Hiroyuki Kokawa; Seung Hwan C. Park; Yutaka S. Sato; Kazutaka Okamoto; Satoshi Hirano; Masahisa Inagaki

doi:10.4028/www.scientific.net/MSF.580-582.9

Paper Titles

Mechanical Approach for Prediction of Microcracking in Multipass Weld Metal of Ni-Base Alloy 690
p.1

Effect of Hydrogen Concentration at Overlay / Base Metal Interface on Repair Weldability of Petroleum Pressure Vessel
p.5

Microstructural Evolution in 304 Austenitic Stainless Steel during Friction Stir Welding
p.9

Effect of Weld Metal Microstructure on Cold Crack Susceptibility of High Strength Weld
p.13

Influence of Heat Input on Mechanical Properties of Multipass Low-Alloy Steel Weld Metal
p.17

Grain Refinement of Titanium Weld by Heterogeneous Nucleation
p.21

Comprehensive Analysis for Microstructure Evolution in Welding
p.25

HomeMaterials Science ForumMaterials Science Forum Vols. 580-582Microstructural Evolution in 304 Austenitic...

Microstructural Evolution in 304 Austenitic Stainless Steel during Friction Stir Welding

Abstract:

The characteristics of microstructures in friction stir (FS) weld of 304 austenitic stainless steel were examined. The stir zone (SZ) and thermomechanically affected zone (TMAZ) showed dynamically recrystallized and recovered microstructures, respectively. The hardness of the SZ was higher than that of the base material and the maximum hardness was located in the TMAZ. The higher hardness in TMAZ was attributed to high density of dislocations and sub-boundaries. Electron microscopic observations revealed that ferrite and sigma phases were formed in austenite matrix in the SZ during friction stir welding (FSW).