Plasma Arc Welding of Modified 12%Cr Stainless Steel

Abstract

This article deals with the plasma arc welding properties of 6 mm thick modified X2CrNi12 stainless steel conforming to the grades EN 1.4003 and UNS S 41003 with carbon content below 0.015% to improve the weldability. The butt welds produced without filler metal and with AISI 316L austenitic type of consumable were subjected to tensile and bend tests as well as Charpy impact toughness testing. Examinations including fractography, metallography, chemical analysis of the weld metal, ferrite content, grain size, and hardness analyses were carried out. Sound plasma arc welded joints of modified 12 Cr revealed the microstructure-property relationship, such as high ferrite content (≥ 70%) resulting in ferrite grain coarsening mainly at the high temperature heat-affected zone (HTHAZ) has no adverse effect on tensile or bend properties, but has negative effects on low temperature toughness. Enhanced toughness was provided in case of the low temperature heat affected zone (LTHAZ) with finer grained microstructure. The increase at the weld metal hardness in Weld 2 is related to the austenitic type of filler used.