Prediction of Heat Input in Automatic MIG Welding

Heat input is a controlling quantity in penetration, base metal dilution and the final metallurgical changes. Heat input also appears in the theoretical equations for peak temperature distribution and cooling rates. Fractional factorial design technique offers a simple means for formulating the heat input equation for the 5 variables of heat input, by finding their main and two factor interaction effects.

The heat input predicting equation war found out as

H = 60/S (-5378.25+97.5 V_oc-30.5 S_D+4.9F+3168.75 D-48.5x) Joules/cm.

The heat input equation was found to be adequate for the variables within the original range. Base metal did not have a great effect on the equation, while the extended range of variables does have an effect on heat input.