Effect of Welding Speed on Texture in Laser-Welded Dual-Phase Steel

The present study makes an attempt to understand the influence of welding speed on the formability of a welded microalloyed steel. An optimum heat input for laser welding was maintained in this study, under bead-on-plate and butt-welding conditions, with varying welding speed. Initially, the heat-affected zone (HAZ) had a moderate γ-fiber texture, which was later distorted with the increased speed of welding. There was an enhancement of rotated cube {001}〈110〉 and cube {001}〈010〉 orientations. The fusion zone (FZ) exhibited mainly random texture, without any presence of γ-fiber. However, faster speeds resulted in strengthening of intensities close to the rotated cube {001}〈110〉 and cube {001}〈010〉 orientations in the FZ. The increased welding speed resulted in enlargement of dimples of fracture surface for the HAZ, finally leading to a transition into a mixed mode of fracture. With increased welding speed, the FZ exhibited a drop in the equiaxiality of the austenite grains. The enhancement of the columnar nature of the austenite grains at the FZ could be correlated with the cube texture formation and deterioration in formability of the welded material.