| 摘要 |
<p>The problems to be solved by the present invention are to restrain the heat input when forming a build-up part to a movable member as well as the adhesive wear generated on a sliding contact surface, thereby improving wear resistance and elongating the durable years. As a means for solving the problems, a valve device includes a build-up part integrally provided to the sliding contact surface of a valve rod or a valve body serving as a movable member. The build-up part is formed by generating pulse discharge between an electrode composed of green compact made from metal as a main component and a portion to be treated in the valve rod or the valve body such that the material of the electrode is welded and deposited on the surface of the portion to be treated. A surface layer is integrally provided to the sliding contact surface of a bush or a sleeve serving as a stopper member. The surface layer is provided by forming a first coating film by the surface hardening heat treatment by metallic cementation. The sliding contact surface of the valve rod or the valve body and the sliding contact surface of the bush or the sleeve come into sliding contact with each other, following the opening and closing operation of a valve.</p> |
