Material Strength Optimization of Dissimilar MIG Welding between Carbon and Stainless Steels

Abstract

This study examines the effects of stick-out, welding current, welding speed, and voltage on the mechanical characteristics and microstructure of MIG welding on SUS 304 stainless steel and S20C steel. The Taguchi method was used to maximize the experiment’s outcomes. Fine columnar dendrites formed at fusion sites, and δ-ferrite phases with dark lines and shapes accumulated between the fusion line and the austenite phases. A welding current of 110 A, voltage of 15 V, welding speed of 500 mm/min, and stick-out of 12 mm were the optimal settings for the ultimate tensile strength (UTS). The UTS value confirmation was 469.4 MPa, which agrees with the estimated value determined using the Taguchi technique. The tensile test revealed that welding current had a far greater impact on mechanical qualities than welding voltage, speed, and stick-out distance. The ideal welding parameters for flexural strength were as follows: stick-out of 12 mm, arc voltage of 15 V, welding speed of 450 mm/min, and welding current of 110 amp. The Taguchi method is useful, as evidenced by the validation of the flexure strength of 1937.45 MPa, which is much greater than the other samples. The impact of the thermal annealing process on the mechanical characteristics of the dissimilar weld joints could be the subject of future research. The investigation results may offer more insightful information about the dissimilar welding field.

Keywords

• microstructure
• Taguchi method
• heat-affected zone
• δ-ferrite
• austenite