APPLICATION OF RSM IN ANALYZING WELD METAL VISCOSITY IN MILD STEEL WELDS

Weld metal viscosity is an integral part of welding process as it plays a crucial role in the weld quality thereby affecting various parameters such as penetration, bead shape and the potential for possible defects since the viscosity influences how molten metal flows and spreads to fill the welded joints. A number of factors such as temperature, composition can affect the weld viscosity leading to porosity, lack of fusion, incomplete penetration. This study applies response surface methodology (RSM) in analyzing weld metal viscosity in mild steel welds. Twenty (20) experimental runs were carried out using TIG welding process while focusing on four key input parameters – Current (A), Voltage (V), Gas flow rate (L/min) and Material Temperature (0C). The weld viscosity at maximum and minimum level was observed to be 0.00898kg/(m-s) and 0.00635kg/(m-s) respectively where the input parameters (voltage, current and temperatures) were 24V and 21V, 220A, 380C and 280C accordingly. This study explicitly shows that RSM can be applied to analyze and predict optimal value for weld metal viscosity.