Optimization of Welding Parameters in Double‐Pulse Metal Inert Gas Welding of 15CDV6 High‐Strength Low‐Alloy Steel for Fabrication of Critical Rocket Components

In this work, an attempt is made to find out the optimized weld parameters in double‐pulse metal inert gas‐welded 15CDV6 high‐strength low‐alloy steel. Three parameters namely wire feed speed, pulse frequency, and amplitude were varied and the weld quality was assessed based on bead width, depth of penetration, and tensile strength. Best and worst weld parameter combinations were identified using Technique for Order of Preference by similarity to ideal solution optimisation technique. Weld obtained through optimised parameter combination had a tensile strength of 867.28 MPa and the weld obtained through worst weld parameter combination had a tensile strength of 212.21 MPa. Compared to the base metal, the best weld had 21% higher tensile strength, and the worst weld had 65% lower tensile strength. A higher percentage of martensite in the microstructure of the best weld played a major role in achieving a high value of tensile strength. The best weld also had lower percentage of ferrite in both the heat‐affected zone and the weld zone compared to the worst weld. Best weld also had a lower percentage of high strain regions than the worst weld as indicated by electron backscatter diffraction results.