Microstructure and Wear Resistance of Single- and Multi-Layered Low-Carbon Fe-Cr-C-Mo-Mn Clads Deposited by Shielded Metal Arc Welding

Different layers of a low-carbon Fe-Cr-C-Mo-Mn electrode were deposited on a plain low-carbon steel using shielded metal arc welding (SMAW). The microstructure, hardness, and wear resistance of the clads were investigated by optical microscope, scanning electron microscope (SEM), hardness test, and sand-rubber wheel wear test. Microstructure of the single-layered clad consisted of lath martensite and a small amount of retained austenite. Three different microstructural regions including plate martensite surrounded by delta ferrite, tempered martensite surrounded by delta ferrite, and tempered martensite were observed at the top, middle and bottom regions of the multilayered clads, respectively. The hardness of single-, double- and triple-layered clads was, respectively, 3.2, 4.1 and 4.3 times more than that of the substrate. The hardness of multilayered clads increased gradually from bottom to the top of the clads. A direct relation was observed between wear resistance and hardness of the clads. In comparison with the single-layered clad, the wear rates of the double- and triple-layered clads were reduced by 33 and 67%, respectively. Wear mechanism changed from severe delamination and abrasion to insignificant abrasion by increasing the number of layers.