Investigation of failure mechanism of dissimilar resistance spot welding of steels

Austenitic and Duplex Stainless steel was majorly preferred for the heat exchangers and the chemical containers. This research work proposed to investigate the failure mechanism of dissimilar welded joints of AISI 347 and DSS 2205. The welded specimens were investigated under tensile shear test, cross tension test, coach peel test, and micro-hardness test. 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 coach peel test, the sample absorbed a maximum load of 4 kN and ductile fracture was witnessed at the vicinity of the nugget. The failure mode in coach peel test was 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 the specimen arrangement and loading conditions.