Self Sealing Integral Free Forging Power Station Gate Valve High-Temperature and High-Pressure Large-Diameter Forged Gate Valve

Self-Sealing Integral Free Forging Power Station Gate Valve

I. Product Overview: Reliable Fluid Control for Extreme Conditions

II. Key Attribute Parameters: Comprehensive Technical Specifications

III. Core Features: Forging Process and Self-Sealing Technology Advantages

1. Advantages of Integral Free Forging Structure
   The valve body adopts integral free forging with a forging ratio ≥5:1, featuring dense and uniform grain structure without casting defects. Compared to castings, tensile strength increases by 30%, impact toughness by 50%, and fatigue resistance by 2x, suitable for frequent start-stop conditions. Ultrasonic testing (UT) shows internal defect rate <0.1%, far exceeding industry standards (≤1%).
2. Innovative Pressure Self-Sealing Design
   The bonnet-body wedge-type self-sealing structure increases sealing specific pressure with medium pressure. At Class 2500, sealing performance is 90% better than traditional flanges, eliminating regular bolt tightening and reducing maintenance. This structure also removes leakage risks from gasket aging, ideal for high-temperature steam and corrosive gases.
3. Wide-Condition Adaptability Design

• Temperature Adaptation: Materials like F91 alloy suit supercritical steam (540℃), while low-temperature steel (LCB) works for LNG terminals (-196℃);
• Pressure Fluctuation: The self-sealing structure automatically compensates for ±30% pressure changes, maintaining reliable sealing;
• Medium Compatibility: Stellite-alloy hardfaced seals enhance erosion resistance 4x, suitable for particle-laden media (e.g., coal powder, catalysts).

IV. Manufacturing Processes: Precision Control for Quality Assurance

1. Raw Material Selection and Pretreatment

• Forging billets use a dual-process of electric furnace and refining furnace, controlling S/P content below 0.015%, verified by 100% spectral analysis;
• Homogenizing annealing before forging eliminates casting stress and improves workability;
• Key materials (e.g., F91) undergo intergranular corrosion testing and high-temperature creep strength tests to meet design requirements.

2. Precision Machining and Surface Treatment

• Valve body sealing surfaces are processed by 5-axis  machining centers with flatness error ≤0.01mm and surface roughness Ra≤0.8μm;
• Sealing surfaces adopt plasma powder surfacing with alloy layer thickness ≥3mm, hardness uniformity within ±2HRC;
• Valve stems use rolling strengthening treatment, increasing surface hardness by 20% and significantly improving anti-galling performance.

3. Full-Process Quality Control

• Pressure Testing: Each valve undergoes 1.5x design pressure shell strength test (30-min hold) and 1.1x pressure sealing test (15-min hold);
• Nondestructive Testing: 100% radiography (RT) for welds, 100% magnetic particle (MT) for surface defects, 100% ultrasonic (UT) for internal quality;
• Life Verification: Sampling for 5,000 on-off cycles with sealing performance decay ≤5%, meeting 20-year design life for power stations.