Effect of Tempering Treatment on the Post-Weld Properties and Chemical Compositions of Arc-Welded Alloy Steels

The effect of heat treatment on welded joints using the shielded metal arc welding (SMAW) on three different types of steel with different carbon ratios under constant conditions such as the welding current 120A, voltage 80V, Diameter 10 mm and angle 60 degree. Hardness tests chemical composition analysis were carried out and it was observed that, high carbon steel has the highest hardness of about 459 on maximum HV value, followed by the low carbon steel with the hardness of 316HV maximum and medium carbon experience the least value of 208HV. Hardness increases with low carbon content as shown in the experimental results which deduced that the low carbon steel used was confirmed to be the high-strength-low-alloy steel of grade 8620-HSLA-Nickel-Chromium-Molybdenum steel. The microstructure of the base metal was analysed before heating to support the results of chemical analysis. Nickel percentage of up to 0.147% and Chromium 0.083%. Molybdenum was just 0.030% which contributed in affecting the mechanical properties of the steel.