Effect of electrode composition over performance of dissimilar stainless-steel welds

Abstract

In this study, the effect of composition of the electrodes ER347 and ER310 is investigated on the microstructure, mechanical and corrosion properties of dissimilar weld between AISI 430 and AISI 304L; made using gas metal arc welding. The mechanical properties were investigated by uniaxial tensile tests whereas corrosion properties were analyzed via polarization tests in H2SO4 (acidic) and NaOH (alkaline) solutions with varying concentrations − 0.1 M, 0.3 M and 0.5 M. It has been found that electrode composition does not change the hardness of the weldments; however it has affected the hardness of heat affected zones (HAZ). Hardness of HAZ near AISI 304L was higher, when the weldment was made using ER 347 due to presence of finer grains in HAZ. In contrast to this, hardness of HAZ near AISI 430 was higher, when the weldment was made using ER 310 due to carbide formation at grain boundaries. Unlike hardness, strength of welded specimens was approximately 54% and 14% lower than AISI 304L and AISI 430 respectively due to the presence of HAZ zones. Width of HAZ zones has also decided the extent of decrease in elongation values, showing the lowest elongation for the welded specimen made using ER347. The higher carbon content can lead to wider HAZ zone, thus not only results in degradation of mechanical properties but also decreases the passivation ability of the welds. At very low pH level (0.44), passive layer can get ruptured and Ni wt. % plays a detrimental role over corrosion resistance of the welds.