Investigation of heat input effect on microstructure and corrosion properties in dissimilar welded joints of A283 GrC steel to 304L stainless steel via SMAW method

In this study, the corrosion behavior of the dissimilar welded joints of 304L austenitic stainless steel and A283 Grade C carbon steel is investigated. For this purpose, the shieldmetal arc welding (SMAW) process with three different heat inputs was conducted using manual electrodes and E309L electrodes with DCEP polarity. After the welding process, the microstructure of the base metals, weld metals and heat-affected zone (HAZ) were examined using optical microscope (OM) and scanning electron microscope (SEM). The results showed that the decrease in heat input led to the formation of the spherical delta ferrite. Also, clear interfaces were formed between the base metal A283 and the austenitic electrode sides. The width of interfaces were increased by increasing the heat input. The corrosion assessments were conducted using potentiodynamic tests in 3.5% NaCl solution. It was found that the welded specimen at heat input of 1225 j / mm exhibited has the best corrosion resistance, which was attributed to the lack of defects and uniformity of the weld structure. Moreover, it was realized that an improvement in corrosion resistance was observed by increasing the heat input. This was due to decreasing the amount of delta ferrite in the weld microstructure

Keywords:

Heat input , Microstructure , Corrosion behavior , Dissimilar welded joints , Stainless steel