Mechanical properties of repair welded joints for automobile body structures

The purpose of this study is to evaluate the mechanical properties of repair spot welding and plug welding for automobile body structures. The lifecycle of a modern car includes different phases. From research and development to production and assembly and finally to the use of the car by the customers. These are the most examined phases, whereas the after-sales sector is a nonetheless important part of the lifecycle. After sales includes the repair of damaged automobile structures after road accidents. Increasing demands for safety and comfort lead to the request for feasible repair methods which create equal mechanical characteristics of the body structures such as the original set up. The joining technologies for modern press-hardened high-strength steels are essential in this context. Testing of lap shear and cross-tensile specimens is used to show mechanical properties of two repair welding technologies. The results show a major loss of strength in the tested joints when using plug welding instead of state of the art repair spot welding. Various analytical methods are moreover used to get a detailed understanding of the influence of both repair welding technologies on the material structure.