Evaluation of coating and wear characteristics of roll surface coated with TiC by electrical discharge coating

The surface texture of a steel sheet exerts a considerable effect on sheet press formability and image clarity after coating. Skin-pass rolling is one of the key processes for determining the surface texture, because the final procedure is transferring an appropriate work-roll surface texture. For stable control of the surface texture by skin-pass rolling, it is important to maintain the topography of the roll surface and increase the roll service life for industrial use. In this study, electrical discharge coating was applied as a means of improving the wear resistance of the roll surface. First, the characteristics of the coating layer made by electrical discharge coating using a TiC sintered electrode were investigated experimentally. Next, the influence of the electrical machining conditions on the layer thickness, hardness, and surface roughness was evaluated and discussed. Furthermore, a rolling experiment was conducted and a prominent wear resistance was evaluated by comparison with a layer fabricated by the conventional hard chromium plating method.