SURFACE TREATING METHOD OF ENGINE VALVE

摘要

PURPOSE: A surface processing method of an engine valve is provided to increase the bend strength of a cotter groove by removing a nitride layer of a cotter groove. CONSTITUTION: A surface processing method of an engine valve comprises: a step of cutting a electrical field of a shaft part(S110); a step of grinding the external diameter of a shaft body using a grinder(S120); a step of positioning the shaft body between whetstones which are rotating(S130); a step of forming a nitride layer through a chemical reaction by dipping an engine valve into softening solution for 30~45 minuets(S140); a step of cooling the end of the shaft body with air(S150); a step of processing the end of the shaft body in 180~250°C(S160); a step of removing a foreign materials and protruding parts from a cotter groove(S170); a step of removing a harmfulness layer by performing a shaft buffing process(S180); a step of grinding a valve face which is formed on a head part with whetstone(S190); and a step of removing foreign materials by washing the engine valve(S200).