Investigation on mechanical and corrosion properties of gas tungsten arc welded similar and dissimilar duplex stainless steel joints

Abstract

This exploration discusses the analysis on similar and dissimilar metal welding of Duplex Stainless Steels (DSS) using Gas Tungsten Arc Welding (GTAW) process. GTAW is the process which is most generally employed in numerous engineering applications such as building of railway coaches, manufacturing of automobile components and chemical industries. DSS complying with 2205 grade is the important material adopted in this research experimentation that ensures more strength and corrosive resistance. DSS is frequently needed to be joined with same grade/material and also with dissimilar materials in various fabrication industries. Joining of dissimilar materials is extensively quite complicated due to the deviations in metallurgical, mechanical and physical properties of the parent materials which are to be welded. The exploration concentrated on the influence of welding persuaded changes in metallurgy on the mechanical behavior and corrosive properties of Super Duplex Stainless Steels (SDSS) weldments. The weldments discussed in this experimental analysis have been fabricated with the use of filler material ER2594 by GTAW process. Microstructural analysis in the welded samples witnessed the evolvement of austenitic (gamma) phases in distinct morphologies such as grain boundary austenitic, needle like elongated austenitic (Widmanstatten structure) and intra-granular austenitic particles. The mechanical behavior of the welded samples attained and compared with the parent material behavior by Vicker smicro hardness evaluation, Charpy s impact toughness analysis, tensile strength and three point bend analysis. The cyclic polarization curves exposed high corrosive resistance for the welded samples than the parent material in NaCl corrosion medium.Nickel enhanced filler ER 2594 results in the nucleation of additional gamma stages in the fusion zone that are electrochemical resistive more than the delta ferritic phases. The segregation of alloying elements were analyzed using EPMA analysis.