BALL VALVE SHUT-OFF MEMBER AND METHOD OF ITS PRODUCTION Russian patent published in 2009 - IPC F16K5/06 

FIELD: machine building.

SUBSTANCE: set of invention relates to pipeline valves and accessories and is designed to be used in production of ball valves intended for transport of gas, oil , oil products, water, steam, chemical and oil chemical products and other liquids, primarily, viscous, corrosive, erosive and abrasive in the conditions of enhanced cavitation wear. The ball valve shut-off member incorporates a spherical plug with a through cylindrical bore and is made from aluminium alloy, cast iron or aluminium-coated steel. The shut-off member spherical surface in contact with the ball valve seat features a protective Al₂O₃ coat with phase composition varying over thickness. In the composition, the content of a-phase of Al₂O₃ increases from outer to inner coat layers. There is the method of producing such shut-off member for ball valve comprising producing the said protective Al₂O₃ coat with a-phase composition varying over thickness and the coat finish machining whereat the coat upper layers with lower content of Al₂O₃ a-phase are removed to keep intact the coat with the Al₂O₃ a-phase in the range of 40 to 100%.

EFFECT: higher antirust and wear resistance, tightness of shut-off member and ball valve seat.

4 cl, 2 dwg