Abstract

Coal crushers are widely used in the industrial mining of coal. Considerable wear occurs due to the abrasive nature of coal, so regular maintenance is required, and currently hardfacing by using electric arc welding is widely used as a remedy. This study aimed to compare the hardfacing between welding methods, such as shielded metal arc welding, flux-cored arc welding, and submerged arc welding with and without added metal powders that will give optimum longevity. The hardfacing was martensitic material that is highly resistant to wear. The results of the study indicate that the welding process with a low-heat input caused less welding dilution than welding with high-heat input. The microstructures in all the hardfacings, when analyzed using scanning electron microscopy, showed martensite and austenite. It was found that a single hardfacing layer contained more alloying elements from the buffer layer than a three-layer hardfacing, resulting in a more austenite phase, lower hardness, and poorer wear resistance. The worn surfaces of hardfacing layers, after wear testing according to ASTM G65, showed mainly cutting and plowing types of wear. The results show that welding with flux-cored wires using the lowest heat input (0.72 kJ/mm) gave the lowest mass loss for both single-layered hardfacing (2343.75 mg) and three-layered hardfacing (1984.50 mg) and is therefore recommended for hardfacing with martensitic materials.