| 摘要 |
PURPOSE:To improve the durability by forming a build up layer made of Mo or W on the seat surface of a valve body. CONSTITUTION:Build up material such as wire rod or powder Mo or W is build-up welded on the seat surface 2 of a titanium alloy valve body 1 by means such as laser welding, a TIG method, PTA method or the like to form a build-up layer 3. As the build up layer 3 has small coefficient of thermal conductivity, heat generated by impact of the seat material on the cylinder head side with the seat surface 2 of the valve body is intercepted. In this arrangement, micro deformation is not caused in the valve body so as to improve durability. |
