Joining of ultra-high-strength steels using resistance element welding on conventional resistance spot welding guns

Abstract

Single-step joining of dissimilar material combinations between ultra-high-strength steels and high-strength aluminium alloys with sufficient mechanical joint properties by using conventional resistance spot welding equipment has not been reported yet. In this research paper, a novel single-step joining technology, so-called self-penetrating resistance element welding, is introduced. First, the motivation for this novel joining technology, the state of the art in joining, and the process characteristics are presented. In the results section, the welding rivet geometry is first determined using forming simulations and validated by head tensile tests. Followed by the description of the welding process and its characteristics, the mechanical joint properties are reported. The results show that a numerically optimised welding rivet geometry can guarantee sufficient joint strength. By this welding rivet geometry, a thermally assisted penetration of aluminium and therefore welding to steel is possible with and without adhesive. Furthermore, it is shown that the welding process can be designed by means of simulations. Finally, the shear tensile tests prove that an overall sufficient joint strength is ensured.

An Overview of Resistance Element Welding with Focus on Mechanical and Microstructure Joint and Optimization in Automotive Metal Joints

“…REW has been studied both experimentally and numerically to improve the quality of the produced welds. Experimental studies on welding quality provide valuable information about the influence of different welding parameters on the weld properties 54) . Despite providing practical information, experimental studies on REW process are very costly.…”

“…The 2D axis symmetric forming simulation model for welding rivet design was developed by Günter and Meschut 54) . The developed model has been employed for analysing the its characteristics and the chemical composition of dissimilar joint for overcoming the metallurgical incompatibility of dissimilar material compounds using a Self-Penetrating Resistance Element Welding(SPREW).…”

“…Therefore, the calculated results are consistent with the experiment by comparing the calculated nugget dimensions and shifting phenomena 62) . Günter and Meschut 54) developed the 2D axis symmetric forming simulation models for welding rivet design as well as 3D welding simulation models for determining the temperature fields and the dynamic resistances during REW process. In this case, only the welding process is simulated since hot penetration cannot be simulated within 3D model due to missing damage criteria in the computational model.…”

“…The experimental results showed that DP steel and CFRP could be joined by REW with the maximum fail-Welding simulation model for two-sheet combination Welding simulation model for three-sheet combination Fig. 5 The developed model for two-sheet combination (upper left) and three-sheet combination (upper right) 54) ure load of 2411.5N and the failure energy of 1.2J, but the joint failed through the weld in the interfacial(IF) mode. It could be indicated that formation of the asymmetrical nugget can be attributed to the differences in electrical resistivity and thermal conductivity.…”

Resistance element welding of aluminium alloy and steel using an element of aluminium

“…Meanwhile, Qiu et al [17] studied REW of AA/MS using a headless rivet as an element; Fei et al [18] processed the prefabricated hole into a conical shape and welded AA and steel using countersunk head rivet as an element. Gunter and Meschut [19] took conical rivet as the element and carried out self-penetrating REW between AA and steel without prefabricated holes. Recently, REW has been used to weld different combinations of AA and steel, such as A6061/22MnMoB [20], A6061/HS1300T [21], A6061/DP600 [22], A6061/Q235 [23], A5052/SPFC980 [24].…”