Optimization of process parameters in friction welding of super duplex stainless steel

Super duplex stainless steel (SDSS) of grade UNS 32750 is a material with high corrosive resistance and strength. Due to these properties SDSS finds application in chemical, and oil industries. Welding plays a crucial role in the above industries for fabricating crucial components. Among the various welding processes, friction welding is least explored in joining SDSS. In this work, Friction welding was used to join SD SS in order to get properties required for oil industries. Welding trials were done based on L9 Taguchi array carried out with friction load (kg), friction time (s), forge load (kg) and forge time (s) as input parameters. The weld quality was assessed by measuring tensile strength and hardness. Grey Relational Analysis was used to identify the optimised parameter combinations. From GRA, it is understood that the optimised parameter combination lies outside L9 welding trials. Confirmation test was done based on the GRA predicted optimised parameters and the experimental results were found to be in good agreement with the predicted values. The metallurgical aspects of the weld are also discussed with the help of microstructures taken through optical microscope.