The microstructure evaluation of dissimilar welds of UNS 32750 super duplex stainless steel to AISI 304L austenitic stainless steel

In this study, the microstructure of dissimilar welding of super duplex stainless steel UNS 32750 to austenitic stainless steel AISI 304L was investigated. For this purpose, gas tungsten arc welding process (DCEN) and two filler metals including ER25104L and ER309LMo were used. The microstructure of the different zone in each joint, including weld metals, heat affected zone, interface were evaluated using optical microscopy was investigated. The investigations showed that austenitic and ferritic structure such as dendrite, weld metal 25104L, with secondary Austenite, 309LMo weld metal was observed as the primary ferrite with austenitic matrix. In addition microstructure was seen as skeleton ferrite morphology. The interface of 304L austenitic stainless steel by two filler metals with epitaxial growth and interface of super duplex UNS 32750 Was seen high ferrite content.