ABSTRACT

The tungsten inert gas welding (TIG) is generally for fusion welding of stainless steel, magnesium alloys nickel base alloy carbon steel and low alloy steels. The project deals with the welding of mild steel bar of 10mm thickness and length of 100mm. The tungsten inert gas welding input parameters include voltage, current and gas combination and were used to obtain the required optimized output response, which are the Ultimate Tensile strength, impact strength and Depth penetration. The combined mixture design approach was employed with the help of the design expert software. Twenty eight (28) runs were generated and the obtained output response was feed back into the software for optimization.

The model produced numerical optimal solution of current of 178.382amp, voltage of 24volts, volume of Argon 54.98% and volume of carbon dioxide 45.02% will produce a weldment with the following properties; ultimate tensile Strength 480.002Mpa, Depth penetration 3.241mm and Impact strength 146.768Mpa. This solution was selected by design expert as the optimal solution with a desirability value of 98.7%.