High-Pressure Main Steam Valve Disc in Steam Turbine
The high-pressure main steam valve disc is the core control elementof the turbine's high-pressure steam inlet system, responsible for precisely regulating the flow and pressure of high-temperature, high-pressure steam entering the turbine's high-pressure cylinder. During normal operation, it adjusts its opening in real time according to grid load demands—maintaining steam parameters within the optimal range for turbine efficiency, ensuring the unit operates at the highest thermal efficiency and reducing fuel consumption. During startup, it opens gradually to control the steam flow rate, avoiding sudden thermal shock to the high-pressure cylinder and protecting the cylinder's inner wall and blades from premature fatigue damage.
It responds quickly to control system commands, with an opening/closing response time of less than 0.4 seconds to adapt to rapid load changes. In emergency scenarios—including turbine overspeed or system failures—it can fully close within 0.2 seconds to cut off the steam supply immediately. This prevents the turbine from continuing to accelerate due to excessive steam input, avoids blade damage caused by overspeed, and provides a critical safety barrier for the entire turbine unit and power plant operation.
Structural Design of Valve Disc
Our turbine high-pressure automatic main steam valve disc adopts a streamlined "dome-shaped" structure, optimized through computational fluid dynamics simulation. This design minimizes steam flow resistance when the valve is open, reducing the pressure drop across the valve disc to less than 0.03 MPa —effectively lowering energy loss in the steam pipeline and improving the turbine's overall energy conversion efficiency.
The sealing surface of the valve disc undergoes precision lapping and plasma spraying of a nickel-based alloy coating. The coating thickness is controlled at 0.1–0.2 mm, achieving a surface hardness of HRC 55–60 and a flatness tolerance of less than 3 μm. Combined with a multi-step "labyrinth" sealing structure, it ensures zero steam leakage when the valve is fully closed (leakage rate < 0.01% of rated flow), avoiding energy waste and corrosion of the valve seat caused by long-term micro-leakage.
The overall structure of the valve disc is optimized via finite element analysis, focusing on stress distribution at key areas such as the connection with the valve stem and the sealing edge. The disc is fabricated from high-strength heat-resistant alloy steel (2Cr12NiMo1W1V or 20Cr3MoWVA), which can withstand thermal stress up to 600 MPa under high-temperature conditions (up to 600°C) and high-pressure environments (exceeding 18 MPa). This optimization eliminates stress concentration points, enhances the disc's fatigue resistance, and ensures stable operation for more than 12 years under cyclic opening/closing conditions (up to 10,000 cycles).
The center of the valve disc is designed with a precision taper hole or keyway structure to connect rigidly with the valve stem. This connection method ensures no relative movement between the disc and stem during motion, avoiding deviation of the sealing surface and ensuring consistent control accuracy over long-term use.
Custom Fabrication per Drawings
We provide precision manufacturing of turbine high-pressure main steam valve discs strictly in accordance with your technical drawings and industry standards. Our production process adheres to strict dimensional tolerances—with the sealing surface's flatness controlled within ±2 μm and the outer diameter within ±0.01 mm.
Guard Turbine Safety & Efficiency—Choose Our Valve Disc!
Our high-performance valve discs ensure precise steam control and reliable emergency protection for your turbine. Contact us now for free technical debugging guidance, customized quotations. We commit to on-time delivery and lifelong after-sales support to meet your turbine unit's maintenance, upgrade, or new-build schedules.
