SUNASURARIIYUSOYOPISUTONHONPUNOBOORUBARUBU

摘要

PURPOSE:To obtain a ball valve with large abrasion resistance by forming a spherical valve with ceramic, making the tensile strength of a valve seat higher than that of the spherical valve, and setting its hardness to the preset value or above and lower than that of the spherical valve. CONSTITUTION:A spherical valve 21 is made of ceramic, and a valve seat 23 is made of nickel chromium molybdenum steel or the like so that its tensile strength is made higher than that of the spherical valve 21 and its hardness is made lower but at Hs 75 or above. The abrasion resistance of the spherical valve and the valve seat is improved by constituting them with these materials, and the life of a ball valve can be sharply improved.