Effects of types of GTAW including superior GTAW-PC with superimposed HF current on mechanical and metallurgical properties of super duplex stainless steel weld joints

Abstract

The manufacturing of a product with super duplex stainless steel generally involve joining using fusion welding techniques. The industries are continuously striving to produce better quality product through use of advanced techniques of welding. Investigation has been done to study the effects of types of GTAW including superior advanced GTAW-PC with superimposed HF current on mechanical and metallurgical properties of super duplex stainless steel weld joints. The weld joints of super-duplex stainless steel (UNS S32750) are prepared using continuous current gas tungsten arc welding (CCGTAW), CCGTAW with superimposed high frequency current, pulse current gas tungsten arc welding (GTAW-PC) and superior advanced GTAW-PC with superimposed high frequency current utilizing super duplex grade electrode over alloyed with 2%–3% nickel (ER2594). The association of high frequency either to CCGTAW or GTAW-PC is a novel technique being utilized in present research. The super imposed high frequency current restricts the arc with almost equal root and projected diameter. The weld joints are characterized with respect to quality of mechanical and metallurgical properties. Both these properties are found superior in case GTAW-PC with superimposed high frequency current as compared to all other types of CCGTAW. The association of high frequency with GTAW and GTAW-PC leads to reduction of weak section of weld joint of width of HAZ along with significantly improvement of associated properties. The superiority of properties due to involvement of high frequency current is explained and justified with the associated science involved.