III. Product Features

• Corrosion Resistance: SS304 stainless steel (CF8) resists pitting, crevice corrosion, and oxidation in humid, acidic, or saline environments. This makes the valve ideal for coastal water treatment plants, marine applications, and chemical processing lines where corrosion is a primary concern.
• Energy-Saving Design: The full-bore flow path and streamlined internal geometry minimize pressure loss (≤5% at rated flow), reducing pump energy consumption by up to 15%. In large-scale water distribution systems, this translates to significant operational cost savings.
• Rapid Closure and Water Hammer Prevention: The valve’s disc responds instantly to reverse flow, closing within 0.5 seconds to prevent water hammer—a phenomenon that can damage pipelines and equipment. This feature is critical in high-velocity systems such as fire protection networks.
• Dual-Seal Versatility: Metal-to-metal sealing (SS304) ensures durability and high-temperature tolerance (up to 425℃), while PTFE soft seals provide API 598 Class VI bubble-tight shutoff for clean media like drinking water or pharmaceutical liquids.
• Easy Maintenance and Interchangeability: Flanged connections allow quick removal for inspection or repair. The valve’s compliance with GB/T 12235 and ASME B16.34 ensures it can replace older valves without modifying pipelines, reducing downtime during upgrades.
• Anti-Static and Fire-Safe Options: Optional anti-static devices (≤10Ω resistance between disc and body) dissipate electrostatic charges, preventing ignition in flammable gas applications. Fire-safe designs (per API 607) maintain sealing integrity during combustion, enhancing safety in petrochemical facilities.

IV. Manufacturing Process

• 1. Raw Material Sourcing and Inspection: SS304 (CF8) stainless steel ingots are sourced from certified suppliers and tested via optical emission spectrometry to verify chemical composition (Cr ≥18%, Ni ≥8%). Mechanical testing (tensile, hardness) confirms compliance with ASTM A351 standards.
• 2. Valve Body Casting: The body is produced via investment casting (lost wax process) to achieve a smooth surface (Ra ≤1.6μm) and dimensional accuracy (±0.05mm). This process eliminates porosity, ensuring structural integrity under PN40 pressure.
• 3. Heat Treatment: Cast components undergo solution annealing (1050–1100℃, water quenching) to restore corrosion resistance and soften the material for machining.
• 4. Precision Machining: Critical surfaces (flange faces, seat grooves, disc guides) are machined using 5-axis CNC centers to achieve tight tolerances (±0.02mm). The seat is lapped to a mirror finish (Ra ≤0.8μm) to ensure uniform contact with the disc.
• 5. Seal and Disc Assembly: PTFE soft seals are compression-molded to fit seat grooves and bonded with high-temperature adhesive. Metal seats (SS304) are press-fitted and laser-welded for permanent attachment. The disc is balanced to ensure smooth movement and prevent sticking.
• 6. Spring and Guide Installation: 316 stainless steel springs are calibrated to provide the correct opening pressure (0.1–0.3 bar). Guide pins ensure the disc moves vertically without lateral displacement.
• 7. Flange and Gasket Integration: Flanges are bolted to the body using ASTM A320 L7 alloy steel bolts, torqued to ASME B16.34 specifications. Spiral-wound gaskets are installed to ensure leak-tight flanged connections.
• 8. Pressure Testing (API 598):
  • Shell Test: The valve body is filled with water and pressurized to 1.5× nominal pressure (e.g., 24 bar for PN16) for 10 minutes. No leakage or deformation is allowed, verified via ultrasonic leak detectors.
  • Seat Test: Air (0.6 MPa) is applied to the inlet, with leakage measured using a bubble counter. Metal-seated valves must meet API 598 Class IV (≤0.15 mL/min for DN40), while PTFE-seated models comply with Class VI.
• 9. Surface Treatment: The valve undergoes passivation in nitric acid (20% concentration) to enhance corrosion resistance. Flanges are shot-blasted to Sa2.5 standard for optimal gasket adhesion.
• 10. Final Inspection and Documentation: Each valve is inspected for dimensional compliance via CMM. Laser marking indicates DN, PN, material, serial number, and certification marks. A complete quality dossier—including material certificates and test reports—is provided.