Laser welding is increasingly used to realize new manufacturing and design concepts.
Specific material problems result from rapid quenching subsequent to welding which causes hard and brittle martensitic microstructures in structural steels. In many cases the gap between the parts is not completely fused and a crack-like defect still remains in the finished structure and causes stress concentrations on loading. Fracture mechanical methods can be applied to predict the behaviour of these defects in case of static and fatigue loading successfully.
Most of the materials used actually are structural steels which can be easily recycled, but there are some trends towards fabrication of complex structures consisting of numerous basic parts made of various materials. Material selection should take recycling aspects into account.
