Fraunhofer IPK

Institute for Production Systems and Design Technology

Resistance Spot Welding

Spot by spot, resistance spot welding uses electric power to melt metal parts. The experts at Fraunhofer IPK have given an old technique a leading high-tech edge.

Even today car bodies are assembled from sheet metal using a technique developed over one hundred years ago. Resistance spot welding is the grandfather of all joining techniques. Yet the advent of high-performance materials and novel material compounds means that the technique has to face ever greater challenges – such as when the various parts of the material to be welded react so differently to heat that welding threatens to rob the workpiece of its special properties.

Furthermore, special materials make it difficult to reach the ­requisite tensile strength in the welded joint. While typical automobile steels have a tensile strength of around 500 megapascals – i. e. lower than the welding spot – the tensile strength of super-high-strength steel can be as high as 1600 megapascals, which turns the traditional welding spot into the weakest link in the construction chain.

Along with investigating issues of tensile strength and material properties, the experts at Fraunhofer IPK are mainly engaged in finding solutions to the specific problems faced by their industry partners – from rectifying unforeseen production errors to developing novel welding systems.