EFFECT OF PROCESS PARAMETERS ON MECHANICAL PROPERTIES IN GMAW

Abstract

ABSTRACT This experimental study was carried out to analyse the effects of process parameters on mechanical properties in Gas metal arc welded mild steel. GMAW process is one of the most efficient process for welding metals like Aluminum, low carbon steels, stainless steels etc which find great use in industries. Due to its versatility it has always been the centre of focus for researchers and industrialists. There are many process parameters which affect mechanical properties and bead geometry such as welding current(wire feed rate), polarity, arc voltage ,travel speed electrode extension shielding gas etc. Out of these wire feed rate arc voltage and speed were chosen for studying their effect on mechanical properties such as ultimate tensile strength, yield strength, percent elongation ,notch tensile strength and impact strength. It was found that with increase in arc voltage and wire feed rate tensile and impact properties decreases while when speed increases the tensile and impact properties also increases. It was also observed that ultimate notch tensile strength of welded metal was found greater than their corresponding ultimate tensile strength clearly stating that the specimens belong to notch ductile category. It was also found that the notch strength ratio of the base metal was more than all the welded specimen. Full factorial technique was used to formulate the experimental layout and to analyse the effects of process parameters on the mechanical properties of mild steel. Regression technique was used to formulate mathematical model .The models developed have been checked for their adequacy and significance by using ANOVA technique and t-test. Main and interaction effects of the process variables on responses are presented in graphical form. Keywords:- Gas Metal Arc Welding (GMAW), mild steel, Full factorial technique.