Abstract
Magnesium, which is the lightest among the metals used as structural materials, has several advantages such as high strength-to-weight ratio and high recyclability. Recently, the demands of dissimilar metal joint of magnesium alloy to steel have arisen for weight reduction in transportation vehicle industry. However, it is well known that joining of magnesium alloy to steel is difficult because of differences in melting point and thermal conductivity between both metals. Therefore, new welding processes with high reliability and productivity for these dissimilar materials are demanded. Laser roll welding is one of the candidates, which is effective for joining of dissimilar metals. In the present work, laser roll welding of magnesium alloy to steel was tried to investigate the effects of the process parameters on the microstructure of the joint and the mechanical properties. As a result, existence of the interface layer consisting mainly of Fe and Al was confirmed, and increase in welding speed led to decrease in the layer thickness. In addition, increase of bonding area at the joint interface led to increase of the joint strength.
