Production of Manual Metal Arc Welding Electrodes with Local Raw Materials
Manual arc welding using flux coated electrodes is carried out by producing an electric arc between the base metal and a flux covered metal electrode with electric current that depends on the type of electrode, material, welding position and the desired strength. The composition of flux coated electrodes is complex and a variety of coatings were used to cater for different types of welding applications. However, in all cases, the coating is formulated to satisfy three major objectives: to form fusible slags, to stabilize the arc and to produce an inert gas shielding during welding. In the research carried out, several flux samples of various local raw materials were collected, their chemical compositions were determined and the results utilized in producing manual metal arc electrodes. The electrodes produced were used to carry out welds on mild steel sections. The basic characteristic test criteria for determining the performance of any electrode were carried out. The samples of the weld metals were analyzed to determine the homogeneity of the chemical composition as a result of the flux coating, welding rod, and base plate materials. It was observed that manganese based flux covered electrode (a local electrode) with tensile strength of 585.8 N/mm2 was able to compete effectively with titanium dioxide based electrode (a foreign electrode) with tensile strength of 606.7N/mm2. This research work therefore, highlights the need to maximize the use of local raw materials aimed at reducing the cost of importation and thereby help in conserving scarce foreign exchange.