Method of forming a spherical recess on the front surface of an engine valve by means of co-extrusion and hot forging

Abstract

A method of forming a spherical recess on the front surface of an engine valve in the process of its co-extrusion and hot forging, intended for use in combustion engines in passenger cars and trucks, in the co-extrusion process of which a preform is formed using a co-extrusion punch, which preform is then forged in the hot forging process using a hot forging punch, wherein in the hot forging process a hot forging punch is used which has a spherical projection on its front surface, by means of which a spherical recess is formed on the front surface of the engine valve being manufactured centrally in its longitudinal axis, characterized in that the spherical recess on the front surface of the engine valve being manufactured is initially formed in the co-extrusion process of the preform,and to create it in this process, a co-rotating pre-extrusion punch (1) is used, which, like the hot forging punch, has a spherical projection on its front surface.