STUDY OF SUBMERGED ARC WELDING OF MILD STEEL WITH IRON POWDER MIXED FLUX

Abstract

Submerged Arc Welding (SAW) is the most widely utilized for joining of thick segments welding like in thick sections. The submerged arc welding gives the high metal deposition rate, having capacity to weld thick areas with longer weld running with proficiently. The design of experiment (DOE) with 3 factors such as arc voltage, travel speed, and %age of iron powder and 5 levels with rotatable Central Composite Design have been used to develop the experimental plan. Response Surface Methodology (RSM) was utilized to build up the numerical models co-relating the process parameters with the reasponses such as bead geometry ( bead width, bead height, and depth of penetration) and residual stresses. The models once created were checked for sufficiency utilizing analysis of varience (ANOVA). From the adequate models the significant terms were chosen utilizing p test. Fundamental and communication impacts of the process parameters on weld bead geometry and residual stresses are displayed in graphical form. The created models can be utilized to forecast the imperative weld bead measurements and control of the weld bead quality by choosing appropriate process parameters values. After performing the experiments, various outcomes are analysed by using RSM. It has been observed that the bead width increases with the increase of voltage, while the change in other two parameters is less. The increase in %age iron powder increases all three bead geometry parameters but increase in penetration is more than the other two bead parameters. Travel speed is most sensitive parameter to all three bead parameter; but depth of penetration is more sensitive towards travel speed. It has also been observed that %age of iron powder, Arc voltage, and welding speed have a significant effect on the residual stress. The welding speed greatly increased the residual stresses over the whole selected input levels (42 – 46 cpm). Whereas, arc voltage has an adverse effect, and the residual stresses value decreased largely at high level (37 Volt). Key words: SAW, DOE, RSM, Bead Geometry, Residual stress and Weld Metallurgy.