Optimization of welding parameters for improving welded joints used in rolling stock structures using experimental and Taguchi technique

Manufacturing involves cutting, machining, and joining processes for making all the mechanical structures in the world. Welding is a joining process where a lot of input variables are involved to achieve good mechanical properties and able to withstand load and stresses during its service. This study presents the effect of welding current, welding speed, and shielding gas flow rate on hardness and ultimate tensile strength in gas metal arc welding which is commonly used in car body structures in railway industries. The response of these process parameters has been analyzed and optimized using the Taguchi method. This study helps to understand root cause analysis of welding defects or to control the process parameters to improve welding joints used in rolling stock structures. From the experimental study it is observed that the optimum process parameters for ultimate tensile strength are 300 amp for welding current, 3 mm/min for welding speed and 10 L/min for gas flow rate for tensile strength and optimum value for hardness is 200 amp for welding current, 4 mm/min for welding speed and 20 L/min for gas flow rate.