Development of a Direct Correlation of Bead Geometry, Grain Size and HAZ Width with the GMAW Process Parameters on Bead-on-plate Welds of Mild Steel

In this study, an experimental work was conducted to correlate the effect of gas metal arc welding (GMAW) process parameters such as wire feed speed, voltage, and contact tip to work piece distance along with interactive variables on bead-on-plate weld characteristics using multiple linear regression analysis and ANOVA (analysis of variance). The different responses such as convexity index, depth of penetration, reinforcement area, deposition rate, width of heat affected zone (HAZ), weld metal grain size and HAZ grain size were studied. The aim of the present investigation is to develop multiple linear regression equations to predict different responses (outputs) as a function of multiple input variables for 'bead-on-plate' type GMAW process. Multiple linear regression equations were first developed for weld bead geometry as a function of several individual and interactive variables. Then an effort was made to effectively predict the grain structure of the weldments as a function of multiple variables. Predicted responses are very close and sometime superimposed on the actual responses which clearly indicate the adequacy of the regression equations.