The impact toughness of novel keyhole TIG welded duplex stainless steel joints

Keyhole tungsten inert gas (K-TIG) welding is a novel, high-efficiency welding method. In this study, 10.8-mm-thick duplex stainless steel (DSS) plates were welded via K-TIG welding, without groove preparation or filler metals. The microstructure, grain size and grain boundary misorientation angle distribution (GBMAD) of the weld metal (WM) were analyzed to characterize its impact toughness. Charpy impact tests were carried out, and the results proved that the impact absorbed energy (IAE) of the WM increases with the increase in heat input. This finding indicates that the austenite volume fraction and the GBMAD have an influence on the impact property of the WM.