Microstructure and fatigue performance of single and multiple linear fiber laser welded DP980 dual-phase steel

The aim of this study was to identify the effect of fiber laser welding (FLW) on the microstructure, hardness, tensile properties and fatigue performance of high-strength (UTS≥980MPa) DP980 dual-phase steel with single linear and multiple linear joint geometry. While FLWed joints showed tempered martensite at the outer heat-affected zone (HAZ) which caused softening in the welds, a lower extent of martensite tempering and higher hardness value …