III. Product Features

• Trunnion Support System: The ball is stabilized by upper and lower trunnions (forged alloy steel, nitrided for hardness ≥HV900), reducing operating torque by 30–50% compared to floating ball valves. This design ensures uniform seat contact and prevents ball sagging under high pressure, critical for Class 600LB applications .
• Hard Seal Technology: Metal-to-metal seats use HVOF (high-velocity oxygen fuel) Spray coating of Stellite or Tungsten carbide – cobalt, achieving a hardness of HRC70+ for abrasion resistance. The seats are precision-ground to a Ra ≤0.4μm finish, ensuring bubble-tight sealing even after 50,000 cycles .
• Pneumatic Actuation: Double-acting actuators provide fast 90° rotation (1–2 seconds), while spring-return models offer fail-safe closure during air loss. Optional smart positioners enable proportional control (±1% accuracy) for process optimization .
• Three-Piece Construction: Bolted body segments allow easy disassembly for maintenance without removing the valve from the pipeline. This modular design reduces downtime by 40% compared to welded valves .
• Safety and Compliance: Fire-safe design (API 607) activates metal-to-metal sealing if soft seals degrade during combustion. Anti-static springs (≤10Ω resistance) dissipate electrostatic charges, preventing ignition in flammable environments .
• Cavity Pressure Relief: Automatic pressure relief valves vent trapped media, preventing catastrophic failure during thermal expansion—critical for gas and volatile liquid service .

IV. Manufacturing Process

• 1. Raw Material Forging: ASTM A105 ingots are forged at 1150–1200℃, then normalized (880℃, air-cooled) to relieve stress and enhance impact resistance. Forged blanks undergo UT and PT to detect internal defects .
• 2. CNC Machining: The body, bonnet, and trunnions are machined using 5-axis CNC centers to achieve tolerances of ±0.02mm. Trunnion bores are honed to ensure smooth ball rotation .
• 3. Hard Seal Application: Seats and balls are coated via HVOF with Stellite 6 or Tungsten carbide – cobalt (thickness 0.3–0.5mm), then ground to a mirror finish (Ra ≤0.8μm) using computer-controlled Spherical grinding machine .
• 4. Assembly: The ball is mounted on trunnions, with the stem connected via a keyway. Graphite packing is layered and torqued to ASME B16.34 specifications. Pneumatic actuators are mounted via ISO 5211 brackets, with torque calibration to match valve requirements .
• 5. Testing:
  • Hydrostatic Test: Shell pressure at 15 MPa (1.5×PN100) for 10 minutes; seat pressure at 11 MPa (1.1×PN100) with leakage ≤0.15 mL/min .
  • Fire Test: Exposed to 750–800℃ flame for 30 minutes, then cooled and tested for leakage per API 607 .
  • Anti-Static Test: Resistance between ball and body ≤10Ω .
• 6. Surface Treatment: A105 components are painted with two coats of epoxy (dry film thickness ≥120μm) for corrosion resistance. Stainless steel parts are passivated in nitric acid .