In situ production of Fe–TiC surface composite coatings by tungsten-inert gas heat source

In the present study, AISI 1045 steel surfaces were alloyed with pre-placed graphite, ferrotitanium and Fe–Cr–B–Si powders by using a tungsten-inert gas (TIG) heat source. The effects of welding parameters and thickness of the pre-placed powder layers on the microstructure and properties of the coatings were also investigated. The results indicated that TiC particles can be obtained by direct metallurgical reaction between ferrotitanium and graphite during the TIG welding process. Most of TiC particles were uniformly distributed in the surface coating. The microhardness showed a gradient variation from the molten boundary to the top surface of the coatings, and it was influenced by the thickness of the pre-placed powder layer and the welding parameters. The surface composite coating exhibited a higher hardness and lower wear rate than that of the substrate due to the formation of TiC carbides.