Star crack

Star cracks occur due to too much stress in the component, usually when the weld cools too quickly or the material is heavily restrained. The cracks then run star-shaped from one point, often from the weld end or a tack. You need to make sure that the component can settle a bit during welding and that cooling is not too rapid. If you see a star crack, the weld is not load-bearing – only grinding out and properly rewelding helps. You can prevent it by preparing the weld cleanly and not concentrating the heat on one point.