Surface treatment of prefinished valve seat inserts

摘要

A prehardened valve seat insert and a process for forming a prehardened valve seat insert for insertion into a cylinder head or an engine block of an internal combustion engine. The process comprises the steps of (a) forming the valve seat insert; (b) precision machining the valve seat insert to precise tolerances so that the valve seat insert can be installed in one of the cylinder head and the engine block without the need for additional seat machining; and (c) treating the valve seat insert to form a wear resistant surface layer prior to inserting the valve seat insert into one of the cylinder head and the engine block.