Influence of pulse frequency on weld bead formation and mechanical performance of 316L stainless steel by double-wire DP-GMAW process

Double-wire double-pulse gas shielded metal arc welding (DP-GMAW) process has more advantages of high cladding rate of DP-GMAW process and high welding quality of GMAW process, so it has been commonly employed in many stainless steel welding occasions. The double-wire DP frequency can affect arc pressure and heat delivery, so further affect many weld bead formation and mechanical performances. This work used the double-wire DP-GMAW process with 316L stainless steel as the parent metal to design five arrays of experiments, so as to explore the influence mechanism of double-wire DP frequency on the weld bead formation and corresponding mechanical performance. Experimental results showed that the stability of welding process can achieve the best when the frequency was 3 Hz; also, an optimal weld bead formation can be obtained. The influence of frequency on the width of reinforcement was so low, but the penetration and weld toe angle were so large. Increasing frequency can obtain obvious fish-scale ripples and small grain size, also, the hardness and tensile strength were also increasing. It can be seen that the double-wire DP frequency can significantly affect the weld bead formation and mechanical performances during the double-wire DP-GMAW process in this work.