Investigation of the failure mechanism of dissimilar resistance spot welding of steels

Abstract

Austenitic and duplex stainless steels are majorly preferred for heat exchangers and chemical containers. This research work investigated the failure mechanism of dissimilar welded joints of AISI 347 and DSS 2205. The welded specimens were investigated using tensile shear tests, cross-tension tests, coach peel tests and microhardness tests. The specimen absorbed a maximum tensile shear load of 18 kN during the tensile shear test, and the failure mode was button pull-out with brittle fracture. The test sample absorbed a load of 15.1 kN during the cross-tension test, and the failure mode was button pull-out with brittle fracture. During the coach peel test, the sample absorbed a maximum load of 4 kN and ductile fracture was observed at the vicinity of the nugget. The failure mode in the coach peel test was of button pull-out type. The microhardness test recorded a maximum hardness of 312.8 HV, which is 78.74 and 7.1% higher than the base metal hardness values of AISI 347 and AISI 2205, respectively. The specimen failed under pull-out failure mode in all the tests, and hence, the weld zone was intact in all specimen arrangements and loading conditions.