| 摘要 |
PURPOSE:To aim at improving the reliablity and durability of a guide bushing by forming a surface layer of heat resisting and wear resisting hard alloy consisting of, as a main component, cobalt or nickel, on the inner surface of the bushing to which a valve stem is slidably contacted, so that the generation of scale is prevented. CONSTITUTION:A surface layer of heat resisting and wear resisting alloy consisting of, as a main component, cobalt or nickel, is formed on the inner surface of a guide bushing 13 in a steam valve. With this arrangement, the generation of scale in the guide bushing 13 is prevented and as well the sticking of a valve stem 2 is prevented beforehand. Further, the wear of the guide bushing 13 is reduced. Thereby the reliability and durability of the guide part of the steam valve is improved. |
