The Effects of Welding Current and Electrode Specifications on the Hardness Properties of Mild Steel Welded Joints

Abstract: The paper discussed the effect of welding parameters on the hardness properties of welded mild steel rod (∅10) using Shielded Metal Arc Welding (SMAW) method. Welding current and electrode specifications were the investigated welding parameters. The mild steel rod was cut into various samples ∅10 by 50mm each with the aid of hacksaw. The samples were machined to some configurations such as single-v edge, chamfered and plain face. Each similar pair of those configurations was welded by arc welding at various welding current with electrode gauge 10 and 12 respectively to produce the needed joints for hardness test. The result showed that increased in the arc welding current resulted in increased hardness of the welded joints for all the selected welding geometries. With respect to electrode specification, electrode gauge 12 gives better/higher hardness value of the welded joints than gauge 10 at the various selected welding currents 120, 160, 200 and 240A. The study therefore recommends that welding at higher current with electrode gauge 12 should be encouraged if higher hardness value of the mild steel welded joint is required.

Keywords: Welding current, Electrode gauge, Shielded Metal Arc Welding, Hardness, Welded joints.