Interface and microstructural characteristics of titanium and 304 stainless steel dissimilar joints by upset butt welding using a gleeble thermo mechanical simulator

This work discusses joining dissimilar material combinations of commercial pure titanium and 304 stainless steel utilizing an upset butt welding process. The process involves rapid heating to a temperature of 1150 °C at a heating rate of 200 °C/s with simultaneous application of pressure at a level of 1.5 MPa to achieve fusion. Then, the joints are post-heated to 850 °C during the soaking period for 90 min to relieve the welding residual stresses and achieve good bond strength. The upset welding experiments are conducted with the help of a Gleeble thermomechanical simulator. This process does not require the conventional severe metallographic preparation generally used for the typical diffusion bonding process. The weld joint achieves an ultimate tensile strength of 274 MPa, approximately 60% of the strength of commercial pure titanium. Moreover, intermetallic compounds occurred at the interfaces, which were attributed to significant changes in the microhardness of the Ti/SS alloy