Structural relationships of metallurgical and mechanical properties influenced by Ni-based fillers on Gas Tungsten Arc Welded Ferritic /Austenitic SS dissimilar joints

Abstract

Coupling and shaft assemblies in paper and pulp industries make use of dissimilar joints of austenitic/ferritic stainless steels AISI 316L and AISI 430. The joining of these 4mm thick Ni-Cr based AISI 316L and Cr based AISI 430 alloys were carried out by adopting current continuous (CCGTAW) and pulsing current (PCGTAW) in Gas Tungsten Arc Welding has been addressed. Ni-Cr based ERNiCr-3 and Ni-Cu based Nb-free ERNiCu-7 filler rods were employed to join these types of dissimilar combinations. The weldments were systematically characterized using optical microscopy (OM) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). It is recommended from the studies that the welds obtained from ERNiCu-7 fillers were free from deleterious Laves phase formation. Irrespective of fillers, the tensile failures were experienced at the base metal side of AISI 430. In ambient temperature condition Charpy V-notch impact trials highlighted that the weld joints employing ERNiCu-7 observed better tensile and impact toughness than current continuous GTAW weldments. This study is highly demanded in paper and pulp industries and effectively addressed the choice of fillers in conquering the Laves phase.