Effect of current and electrode diameter of gas metal arc welding (GMAW) on mechanical properties and microstructures of JIS G3101 SS400

Heavy equipment manufacturing industry keeps growing along with the increasing market demand. One of the production line used in the manufacturing process was welding. In order to produce high-quality welding consistently, optimal selection of welding parameters was needed. Therefore, this study was conducted to analyze the influence of current and electrode diameter ER70S-G KC26 of gas metal arc welding (GMAW) on the mechanical properties and microstructure of JIS G3101 SS400 welded joint. The variables of electric current were 320, 420 and 520 amperes while the electrode diameters were 1.2 and 1.4 mm. The results showed the highest hardness was 209.8 HB while the lowest was 171.6 HB, the highest UTS value was 569.3 MPa while the lowest was 531.4 MPa, the highest elongation percentage was 56% while the lowest was 38%. The results of microstructure showed that HAZ was dominated by lath martensite, bainite and polygonal ferrite while in the weld region it was dominated by acicular ferrite, widmanstätten ferrite, and polygonal ferrite. Both current and electrode diameter ER70S-G KC26 affects mechanical properties and microstructures of welded joint JIS G3101.