Microstructure and wear resistance of low carbon steel surface strengthened by plasma melt injection of SiC particles

Low carbon steel Q235 sheets were processed with plasma melt injection (PMI) of SiC particles. The sheets were melted by a transferred plasma arc and injected with fine (178 to 250 mu m) and coarse (420 to 840 pm) SiC particles. Microstructure of the specimens was investigated with scanning electron microscope (SEM), energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD) analyzer. Micro-hardness of the specimens was tested. Dry sliding wear test was performed on the specimens with a W6Mo5Cr4 V2Co5 steel roller. The results show that microstructure of the specimen with fine SiC particles injected consists of iron-based matrix and pearlite. No SiC particles are found in the melted layer. Microstructure of the specimen with coarse SiC particles injected consists of iron-based matrix, pearlite and graphite. Some coarse SiC particles are found embedded on the top surface of the specimen. The wear resistance of low carbon steel can be improved with PMI of both fine and coarse SiC particles. Wear loss of the specimen with coarse SiC particles injected is lower than that of the one with fine SiC particles injected. The SiC particles protect the matrix from worn out by the counter part and increase the wear resistance of the specimen. (c) 2008 Elsevier B.V. All rights reserved.