AISI 1020 steel is widely used in construction, where its assembly requires Shielded Metal Arc Welding (SMAW). The welding process leads to a decrease in its corrosion resistance properties. To overcome this issue, the Post Weld Heat Treatment (PWHT) method has been developed to improve its corrosion resistance. The welding process utilizes the Shielded Metal Arc Welding (SMAW) method with process parameters such as a but joint connection type, a current strength of 60, voltage ranging from 20-26 V, and RD460 welding electrode. The conducted tests include microstructure testing, hardness testing, and wear resistance testing in seawater. Post Weld Heat Treatment (PWHT) is carried out at temperatures of 400, 500, and 600 °C, with holding times of 1, 2, and 3 hours. The test results indicate that higher temperatures and holding times result in a more homogeneous microstructure, decreased hardness, and lower corrosion rates. The reduction in corrosion rates is attributed to the increasing homogeneity of the microstructure and the decrease in residual stress.