What materials are used for power station valves?
Power station valves require materials capable of withstanding high temperatures and pressures. TANGGONG uses WC6 (1.25% Cr-0.5% Mo) and WC9 (2.25% Cr-1% Mo) chrome-moly cast steel for superheated steam service up to 650C. C12A (9% Cr-1% Mo) is used for the highest temperature applications. For boiler feedwater, forged A105 carbon steel or F22/F91 alloy steel is standard. Stainless steel (CF8, CF8M) is used for corrosive or high-purity applications. Trim materials include Stellite, 13Cr, and 316 stainless steel.
What is the difference between WC6 and WC9 chrome-moly steel?
WC6 (ASTM A217 Grade C5 equivalent, 1.25% Cr-0.5% Mo) is suitable for service up to approximately 590C and is commonly used for main steam and hot reheat isolation valves. WC9 (ASTM A217 Grade C12, 2.25% Cr-1% Mo) offers higher creep strength and can serve up to 650C, making it the preferred material for supercritical boiler applications. C12A (9% Cr-1% Mo-V) extends service temperature further with excellent oxidation resistance for ultra-supercritical plants.
What certifications are required for power plant valves?
Power plant valves typically require ISO 9001:2015 quality management certification, CE marking (EU Pressure Equipment Directive 2014/68/EU), and TUV certification. For specific applications, ASME Section I (boiler external piping), ASME B31.1 (power piping), and PED compliance may be required. TANGGONG can provide full material certificates (EN 10204 3.1/3.2), NDT reports, and third-party inspection by TUV, SGS, Lloyd's, or BV.
Can TANGGONG supply nuclear-grade valves?
TANGGONG can supply valves for balance-of-plant (BOP) applications in nuclear power stations, including cooling water systems, fire protection, auxiliary steam, and service water. For nuclear safety-related (ASME Section III, Class 1/2/3) applications requiring N-stamp certification, please contact our engineering team to discuss specific project requirements and qualification scope.
What is a turbine bypass valve?
A turbine bypass valve is a critical control valve that directs main steam around the steam turbine to the condenser during turbine startup, shutdown, or load rejection events. It is typically an angle-pattern globe or control valve with electric or hydraulic actuation for fast response. The valve must handle full main steam pressure and temperature while reducing pressure and desuperheating steam for safe condenser entry. TANGGONG manufactures turbine bypass valves with WC9 or C12A body and Stellite-faced trim for severe service.
