Investigations of mechanical,microstructural,and corrosion properties of dissimilar welds between DSS 2205 and X70 using shielded metal arc welding

Abstract

The present study developed shielded metal arc welding (SMAW) electrodes for the dissimilar welding of API X70 and DSS 2205 steel alloys, vital for marine applications that require strong joints. Using a mixture design approach, laboratory-developed electrodes improved weld quality and structural integrity. The lab-made electrodes worked better than commercial ones. They had a maximum ultimate tensile strength of 684.367 N/mm², which was higher than that of API X70 and the same as that of DSS 2205 base metals. A yield strength ratio of 0.967, improved impact strength, and superior corrosion resistance were observed. Electrochemical tests revealed that the lab-made electrodes exhibited significantly higher E_Corr values compared to commercial electrodes. These values were −135 mV in the weld zones, −161.85 mV at the DSS interface, and −387.15 mV at the X70 interface. The refined microstructure, characterized by controlled silicon levels and reduced impurities, significantly improved weld strength, validating the lab-developed electrodes as a superior alternative for marine applications.