The Influence of Electrode Parameters on the Size of Heat Affected Zone (HAZ) of Mild Steel Welded Joint Using Taguchi Technique in Automated Shielded Metal Arc Welding

Abstract

The mild steel AISI1080 has good characteristics of mechanical properties and weldability and commonly used in different types of industrial applications. In this research, the high heat temperature transfers to the welding area and formed the heat-affected zone (HAZ). The reducing size of HAZ is a key issue due to the welding because the properties of the materials such as grains structures were changed by the high heat input energy in HAZ so this zone properties weaken than base metal also the mild steel AISI1080 is used to weld by the automated based shielded metal arc welding for increasing welding accuracy and efficiency. The size of HAZ is observed in this research. The welding parameters are set by the Taguchi orthogonal arrays (OAs), that included welding speed (range from 3.19 to 4.6 mm/s), welding angle (range from 45° to 60°) and electrode diameter (range from 2.6 to 4.0 mm). The welding samples were clamped in the butt joint of closed square configuration to weld by ABSMAW and these samples were ground with Silicon Carbide paper (\(\mathrm{S}\mathrm{i}\mathrm{C}\)) and etched with Ferric Chloride (\({\mathrm{F}\mathrm{e}\mathrm{C}\mathrm{l}}_{3})\) solution. The Heat Affected Zones (HAZ) were measured and calculated by the digital microscopy (DM). According to the Taguchi analysis, the experiment found the inverse relationship between the welding speed and size of HAZ, means the welding speed increases, then the size of HAZ decreases as the low heat input and slow cooling rate. In contrast, the research found the direct relationship between the welding angle and the size of HAZ that means when size of HAZ increased, the welding angle increases.