WIDERSTANDSPUNKTSCHWEIßEN VON SCHWARZ-WEIß-MISCHVERBINDUNGEN

Abstract

In vehicle construction and in appliance industry joints between  thin plates of high-strength and ultrahigh-strength ferritic steels  with high alloyed austenitic CrNi steels can be necessary. In both fields of industry the resistance spot welding is an established welding  process because of its high automation and efficiency. The specifics of dissimilar welds between autenitic and ferritic steels are, on the one 
hand, the different thermophysical properties, which can generate a displacement of the welding spot in the austenitic material. On the other  hand there is the possibility of the occurrence of a undesirable increase or decrease of hardness in the welding spot or at the fusion line to  the ferritic steel. This is caused by the combination of materials used and the associated diffusion processes. Further specifics can be an  increasing hardness or the occurrence of cold cracks in the heat affected zone of ultrahigh-strength ferritic steels. The article presents  selected results to the mentioned problems and provides information about achievable welding ranges, possible mode fractures and hardness  values as well as changes of the material characteristics depending on different welding programs.