Modeling the Effect of Plate Thickness on Dilution and Bead Height in SAW Process

Objectives: Dilution and bead height model generation for submerged arc welding and variable plate thickness Methods/Statistical Analysis: Central composite design (rotatable) technique used with Design Expert® software. 32 beads on plate specimen welded with submerged arc welding process. Current, voltage, plate thickness, travel speed and nozzle to plate distance taken as variable to identify the direct and interaction effects of these parameters on dilution and bead height. All weld samples cut from the specimen, polished and etched with 2% Nital solution to observe bead profile on high resolution microscope with 10 X image enhancement for quality measurement of bead parameters. Findings: Plate thickness along with other welding parameters affects the bead profile due to change in heat flow conditions. Variable plate thickness model for bead parameters help us to understand that how the changed heat flow conditions affects bead profile when plate thickness changes. Bead height increase with current and reduce with travel speed. The maximum bead height has been observed with 14 mm plate where bead height is observed 2.94 mm at 325 amperes current and 21.25 m/hr of travel speed while minimum is 1.79 mm for 12 mm plate at 250 Ampere current and 22.50 m/hr travel speed. Higher bead height is observed with thicker plate due heat sinking effect in thickness direction. Percentage dilution is affected by plate thickness along with other parameters, especially when we work with faster travel speed. Application/Improvements: Variable plate thickness model for bead height and dilution for Submerged arc welding represented which can be helpful to identify bead characteristics over a wide range of thicknesses for SAW welded carbon steels.