DN600 Manual Full-Bore WCB Cast Steel Flange Type Wedge Gate Valve

III. Core Features: Optimized Design for Large-Diameter Pipelines

1. Full-Bore Flow Path Design
   The flow path diameter matches the pipeline inner diameter (DN600 flow path ≥600mm), with a flow coefficient Cv 40% higher than reduced-bore valves, reducing pressure loss by 35%. Field tests in crude oil long-distance pipelines show that the pressure drop of the DN600 valve at 10m/s flow velocity is only 0.2bar, significantly improving pipeline transportation efficiency and reducing pump power loss.
2. Wedge Elastic Gate Technology
   The gate adopts a single-lobe elastic structure, compensating for temperature deformation (thermal expansion coefficient 1.2×10⁻⁵/℃) through a central groove, ensuring tight fit with the seat under -29℃~425℃ temperature fluctuations and avoiding jamming. The sealing surface is overlaid with hard alloy on the body material, with surface hardness reaching HRC45~50, doubling the erosion and wear resistance, suitable for crude oil media with minor solid particles.
3. Multi-Sealing Structure Design

• Main Seal: Metal hard seal between seat and gate, meeting API 598 bubble-tight standard (leakage rate ≤0.15×DN mm³/s);
• Auxiliary Seal: Stem uses double seals of V-type packing + O-ring to ensure external sealing reliability under high pressure. The packing gland is designed for online replacement without valve disassembly.

4. Operation Mechanism Optimization
   The manual type is equipped with a large-diameter handwheel (DN600 handwheel diameter ≥600mm), with operation torque ≤400N·m, supporting single-person operation; the electric type can be equipped with an intelligent actuator (protection class IP68), integrating opening feedback and fault diagnosis functions, adapting to the automation control needs of petroleum platforms.

IV. Manufacturing Processes: Precision Control for Large-Diameter Valves

1. Casting and Pretreatment Processes

• The valve body uses resin sand precision casting, with gating positions optimized by flow simulation to reduce shrinkage and slag inclusions; the blank is annealed at 900℃ to eliminate casting stress, with hardness controlled at HB170~200;
• WCB material strictly controls sulfur and phosphorus content (S≤0.05%, P≤0.04%), verified by spectral analysis and tensile testing to ensure mechanical properties comply with ASTM A216 standards.

2. Machining and Surface Treatment

• CNC vertical lathes machine the valve body flange surface with flatness error ≤0.05mm/m and roughness Ra≤12.5μm; sealing surfaces are ground by special grinders with flatness ≤0.01mm and roughness Ra≤0.8μm;
• The stem is quenched and tempered (hardness HB220~250) and chrome-plated (coating thickness ≥20μm), tripling corrosion resistance, suitable for humid offshore platform environments.

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), with soap water for external leakage detection and bubble method for internal leakage;
• Nondestructive Testing: 100% magnetic particle inspection (MT) for valve body surfaces, 100% radiography (RT, Grade II qualified) for welds, ensuring no defects like cracks or pores;
• Life Testing: Sampling for 3,000 on-off cycle tests, with sealing surface wear ≤0.1mm and operation torque change ≤15%, meeting the petroleum industry’s 10-year design life requirement.