| 摘要 |
Provided is an engine valve which, in order to respond to the increasing severity of the usage environment without requiring a complicated structure, can ensure the required durability by means of a generic cobalt base build-up metal and a simple treatment step. This engine valve is formed from an engine valve valve base comprising a shaft part and a cap part that is at one end of the shaft part. A ring-shaped cladding section (13) is provided, by means of build-up welding, on the cap part, and a face (F) is provided which forms a surface hardening layer on the cladding section (13). The build-up metal of the cladding section (13) is formed from a Co base abrasion proof alloy, and the surface hardening layer is an oxide film having a dispersed nitride layer that is nitride formed in accordance with the distribution of iron scattered on a finished surface, by means of a nitriding treatment of the entire valve base after forming the finished surface on the cladding section (13). |
