Ti alloy poppet valve and surface treatment thereof

摘要

A poppet valve in an internal combustion engine of a vehicle consists of a valve body which comprises a valve stem and a valve head at one end of the valve stem. An oxidized layer is formed on portions of the valve body which contacts another valve-operating member. On the oxidized layer, a carburized layer is formed to cover the whole surface to increase wear resistance and fatigue strength of the valve.