Effects of Welding Speed on the Microstructure and Corrosion Behavior of Dissimilar Gas Metal Arc Weld Joints of AISI 304 Stainless Steel and Low Carbon Steel

The weld joint is always the failure point in the arc welding of dissimilar metals due to microstructural heterogeneity. In this work, the microstructure and corrosion performance of gas metal arc weld (GMAW) joints between AISI 304 stainless steel (SS) and low carbon steel (LCS) were investigated under varying welding speed. ER309L wire electrode was used. The corrosion of the weld joints was investigated in de-aerated 3.5 wt.% NaCl solution. The microstructure of the weld joints which exhibited better grain refinement than the HAZ comprises of ferrite, retained austenite and delta-ferrite phases. The welding electrode compensated for Cr and Ni loss (due to dilution) in the weld joints. Cr and Ni composition in the weld joints are higher than the base metals and increased as the welding speed reduced. The corrosion performance of the weld joints was influenced positively as the welding speed decreased. The effects of the welding speed on the microstructure and corrosion performance of AISI 304 SS and LCS dissimilar GMAW has been determined.