Microstructures of Hardfaced Overlay on Low Carbon Steel by Gas Tungsten Arc Melt Injection of Diamond Grits

Abstract

Ni-coated diamond grits were injected into hardfaced Ni-based alloy overlay on a low carbon steel substrate as reinforcing particles with a gas tungsten arc melt injection method. Microstructures of the hardfaced overlay were investigated with scanning electron microscope, energy dispersion spectroscopy and X-ray diffraction analyzer. The results showed that the Ni coating on the injected diamond grits was sound and the diamond grits were not damaged thermally. A very thin layer of TiC formed on the interface between the diamond and the Ni layer. In the overlapped region of the multi-passes specimen, the diamond grits injected in the previous pass were damaged thermally, while the ones injected in the successive pass were not.