Effects of (Ti,W)C on the properties of Stellite12 overlays

The Stellite12 overlay and (Ti,W)C-reinforced overlay have been successfully manufactured on the Q235 steel by plasma arc powder surfacing and effects of (Ti,W)C on the properties of Stellite12 overlay have been studied. Microstructure has been investigated using optical microscope(OM), scanning electron microscope(SEM) with energy dispersive spectroscopy(EDS). Results show that the addition of (Ti,W)C changes the Stellite12 overlay characterized by the Co-rich solid solution and eutectic structure to the (Ti,W)C-reinforced overlay characterized by the dispersed (Ti,W)C particles, fishbone dendrites and blocky dendrites. Microhardness and macrohardness have been evaluated using Vickers hardness tester and Rockwell hardness tester. Results show that macrohardness has been improved when (Ti,W)C is added into the Stellite12 overlay. In addition, the results of electrochemical testing show that the corrosion resistance of the (Ti,W)C-reinforced overlay is better than the Stellite12 overlay.