VALVE ROD BANKED WITH MATERIAL HAVING HIGH HARDNESS

摘要

PURPOSE:To prevent generation of crack in a seat portion surface by providing a valve rod banked with a material having a high hardness, the surface layer of which is more than 1.5mm. in thickness, the intermediate layer thereof being more than 3mm.. CONSTITUTION:A valve rod includes the surface layer 10 of a two-layer valve seat having a thickness of more than 1.5mm. to increase rigidity of the surface layer itself and an intermediate layer 9 having a thickness of more than 3mm. to back up the surface layer.