Morphology and distribution of M7C3 and TiC in situ synthesized in plasma surfacing

In order to systematically study the morphology and distribution of M7C3 and TiC which in situ synthesized by plasma arc in the surfacing layer, plasma arc was used to clad the Fe-Cr-Ti-C wear-resistant alloy on low-carbon steel. And high corrosion experiment was applied to the surfacing layer. The hardness, microstructure and phase constitution of the surfacing layer were investigated through the tests of hardness, OM, EDS, SEM and XRD analysis. The results shows that irregular hexagonal (Cross-section) and strip (Side) M7C3 and petal-like, granular TiC were in situ synthesized in the surfacing layer. The M7C3 and TiC was combined closely. The M7C3 grains which closed to the fusion line of the base metal and surfacing layer are fine, but the ones that away from the fusion line are larger caused by the large temperature gradient. Smooth metallurgical bonding layer was formed between the surfacing layer and the base metal, it has a good metallurgical bonding. The phenomenon that carbon diffusion into the base material was clearly, the hardness near the fusion zone was improved effectively.