Dissimilar Welding of AISI 309 Stainless Steel to AISI 1020 Carbon Steel Using Arc Stud Welding

In present work, AISI 309 stainless steel studs were joined to AISI 1020 carbon steel sheets by arc stud welding technique. A range of welding currents and times were applied to investigate the effect of welding parameters on microstructure and mechanical properties of the weldments. The microstructure observation revealed that increasing of welding current and time encourages martensitic transformation in heat affected zone of carbon steel and gives a high possibility to the formation of sigma phase in fusion zone of stainless steel. Microhardness test showed highest hardness of 575HV in fusion zone at 800A welding current and 0.35s welding time because of hard and brittle sigma phase. The strength of the joints was evaluated using torque test. Maximum torque strength of 60N.m was registered with 400A and 0.35s that also showed the best weld integrity. A crack was detected in the fusion zone at 800A welding current due to the difference in thermal expansion coefficient between stainless steel and carbon steel.