Its superior economic benefits and the possibility of complete automation make resistance spot welding a well suited welding process for mass production parts made from thin sheets. For this reason, it is and remains the dominant joining method in car body production. The numerous advantages of the method are opposed by the disadvantage of the required two-sided accessibility to the joint, resulting in significant limitations in design and construction freedom and the possible production sequences. To facilitate a light-weight and resource-saving automobile body, it is one aim of the designers to reduce the width of joining flanges or to find a flangeless design. This is, for example, achieved by the use of internal high-pressure formed (hydro formed) components. As there is no accessibility to both sides of the joint, it is not possible to use conventional resistance spot welding for constructions made with such components. The indirect resistance spot welding without a backing behind the joint meets the requirement of a one-sided accessibility and also holds many advantages of conventional resistance spot welding. As there is no direct current and force dissipation, this generates some process-specific peculiarities. These include restriction of electrode forces to avoid deformation in the component to be welded, as well as limitations of the sheet thickness and sheet thickness ratios. Moreover, changes in the contacting conditions due to local deformation occurring at the joint lead to atypical spot geometry and position. As an example, the formation of a toroidal spot weld can be observed. The ISF examines the process-specific details of the procedure and potential applications in modern cost- and weight-saving lightweight bodies made of steel hollow sections. The range of possible applications of indirect spot welding and the properties of the resulting joints are shown in this paper by way of several examples.
Indirect resistance spot welding without backing
Indirektes Widerstandspunktschweißen ohne Gegenlage
2014
8 Seiten, 6 Bilder, 1 Tabelle
Aufsatz (Konferenz)
Englisch
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