Effect of Heat Input on Emissions during Shielded Metal Arc Welding of Mild Steel

This paper reports the effect of welding heat input on welding emissions and its compositions during shielded metal arc welding (SMAW) of mildsteel plates. Five levels of heat input were used to fabricate the joints. Fume generation rate (FGR) and percent fume were determined by AWS methods. Composition of welding fume (particulate emission and gaseous emission) was evaluated. Mechanical properties (strength, hardness and toughness) and microstructural analysis of the weld deposits were evaluated. It is found that lower level of welding heat input is beneficial to weld mild steel by SMAW process due to lower level of welding emissions and superior mechanical properties of the joints.