采气闸阀密封面喷焊工艺及性能

Spray welding techology for sealing surface of gate valve on gas production wellhead

采气井口闸阀在含硫天然气介质中工作，密封面失重腐蚀、应力腐蚀及磨损是其主要失效形式。采用2Cr13钢为基体，用氧－乙炔火焰喷焊工艺在阀板、阀座密封面上喷焊镍基自熔性合金粉末，可获得性能优良的表面防护层。喷焊层抗摩擦磨损及磨粒磨损性能与镀硬铬件相同；在5％和10％H2SO4恒温溶液中的腐蚀速率分别是镀铬件的1／14和1／16，具有优良的抗蚀性；喷焊层抗拉强度为218～294MPa，与基体的结合强度相当，完全满足采气闸阀密封面的使用要求。

The main failure pattems of the sealing surface of the gate valve of a gas production wellhead working in sulphurous gas include weight loss corrosion, stress corrosion and wear. By taking 2Cr13 steel as base material, and spraying nickel base self-fluxing alloy powder on the sealing surface between the valve plate and seat with oxy-acetylene flame spray welding technology, good protection layer can be obtained. The welded layer has the same friction wear resistance and abrasion resistance as the chronium plating elements, and higher cormsion resistance. The tensile strength of the welded layer is 218 ~ 294MPa, therefore can satisfy the operation requirements of the sealing suffoce of the gate valve on gas production wellhead.