Effects of complex carbide fraction on high-temperature wear properties of hardfacing alloys reinforced with complex carbides

A correlation was made of microstructure, high-temperature wear resistance, and surface roughness in hardfacing alloys reinforced with complex carbides. The hardfacing alloys were deposited twice on a low-carbon steel substrate by a submerged arc welding method. In order to investigate the effect of complex carbides, different fractions of FeWTiC and WTiC carbide powders included inside hardfacing electrodes were employed. Hot-rolling simulation test was carried out using a high-temperature wear tester. Microstructural analysis indicated that cuboidal and rod-type complex carbides were homogeneously distributed in the bainitic matrix. As volume fraction of these complex carbides increased, hardness and wear resistance increased. The alloy reinforced with FeWTiC carbides contained more complex carbides in the harder matrix than those reinforced with WTiC carbides because of efficient melting and solidification during hardfacing, and thus showed the best wear resistance and excellent surface roughness. Hardness, wear resistance, and surface roughness of the hardfacing alloys reinforced with complex carbides were improved in comparison to high speed steel rolls because of the homogeneous distribution of hard, fine complex carbides in the bainitic matrix.