COMPARATIVE STUDY OF HEAT AND METAL TRANSFER IN GAS METAL ARC WELDING (GMAW)

Abstract

Gas metal arc welding is the one of major process of welding in which an electric arc forms between a consumable wire electrode and the metal work piece, which heat the metal work piece causing them to melt and join. In the recent years great development are being made in this area to optimize and improve the welding performance with high efficiencies and more production rate. The objective of this research is to find the optimized parameters in gas metal arc welding for the application of steel. The effect of force and velocity with which the droplet fall in the weld pool during the welding process are analyze and effect of different shielding gases used in the welding process are also analyze by varying the percentage of different shielding gases during the welding process. During the welding process different types of forces are effect on the droplet from which some forces act as an attaching forces and some behave like a detaching forces. These forces are calculated by modified force balance model (MFBM) method analytically. Arc covered angle during the welding process has also influence the metal transfer. In the range of 0o-30o angle force on the detaching droplet is lower and the droplet did not follow the path and welding process is not feasible. But in the range of 65o to 100o angle variation in the drop detachment is very low so 90o angle is very feasible for the metal transfer. To calculate the hitting velocity and force with which the droplet fall in the weld pool, equations of motion are used. To observe the effect of the shielding gas we use different inert gases and reactive gases. Effect of pure argon, different percentage of O2 mixed with the argon, and different percentage of CO2 mixed with the argon observed that was show that while increasing the percentage of CO2 for certain instant till 20% it will show the very good results, after that the heat transfer is increase to the base metal and weld pool has more fluidity then that of pure argon or other blend of shielding gas and calculated results are compared with the experimental data.