Analysis of weldability of dual-phase steel used in automotive industry

This paper deals with the problems of weldability of high strength dual-phase steel sheets used in the car body production. The properties of the joints made by resistance spot welding (RSW) and laser welding were analysed. The two grades of dual-phase steels such as DP 600 and DP 800 were used. The joints were made by overlapping of two sheets in the method 21 according to EN ISO 4063 (RSW), and as butt weld without a gap by laser welding (method 52 in EN ISO 4063). The parameters of RSW and laser welding were chosen according to the recommendations of IIW. The quality of welded joints was evaluated by visual control, static tension test, and a microstructural analysis of the joints on the light microscopy.

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