TIANYU Trunnion Mounted Flanged Carbon Steel Ball Valve – DN350 Class 150-600 API 6D/608 Compliant High-Pressure Valve for Oil & Gas Pipelines, Natural Gas Transmission & Industrial Production

I. Product Overview

II. Key Attribute Specifications

A. Dimensional & Pressure-Temperature Parameters

• Port Size: DN350 (14”) as the flagship size, with a full-port configuration as standard. The full-port design ensures the valve’s internal bore matches the pipeline diameter (350mm), minimizing pressure drop (Cv value up to 1200 for DN350) and enabling pipeline pigging/cleaning—critical for oil & gas transmission lines. The valve is also available in a size range of DN100 to DN600 (4” to 24”) to accommodate diverse pipeline requirements.
• Pressure Rating: Class 150 to Class 600 (PN25 to PN100), aligning with ASME B16.34 pressure-temperature ratings for carbon steel. Hydrostatic testing follows API 598: 1.5× rated pressure for the valve shell (body/bonnet) and 1.1× rated pressure for seats—ensuring no leakage, sweating, or structural deformation under operating conditions.
  • Class 150/PN25: Suitable for low-to-medium pressure natural gas distribution and industrial fluid systems.
  • Class 300/PN40: Ideal for refinery process lines, oil gathering pipelines, and natural gas transmission.
  • Class 600/PN100: Engineered for ultra-high-pressure applications such as offshore oil wellheads, high-pressure gas pipelines, and industrial reactor feed lines.
• Temperature Range: -29℃ to 425℃, optimized for carbon steel’s thermal stability and hard-seal compatibility. This range covers ambient natural gas, heated crude oil, and high-temperature industrial media (e.g., process steam), outperforming soft-sealed valves that degrade above 200℃.

B. Material Composition

• Valve Body & Bonnet:
  • A105 Forged Carbon Steel (ASTM A105): For Class 300-600 high-pressure applications, offering superior tensile strength (485–655MPa), yield strength (≥240MPa), and impact resistance. Undergoes normalizing heat treatment (900–950℃, air-cooled) to relieve internal stresses from forging.
  • WCB Cast Carbon Steel (ASTM A216): For Class 150-300 medium-pressure applications, providing cost-effectiveness and reliable performance in non-corrosive media.
• Ball & Trunnions: Solid carbon steel (A105/WCB) ball with precision-ground surface finish (Ra ≤0.2μm) for uniform sealing contact. Trunnions (upper/lower) are integral to the ball, made from the same carbon steel material and surface-hardened (HRC 30–35) to reduce wear. For abrasive media (e.g., natural gas with sand particles), the ball’s sealing surface is hard-faced with Stellite 6 (cobalt-chromium alloy, HRC ≥58) to extend service life by 3–5 times.
• Seal Materials:
  • Hard Seal: Metal-to-metal sealing with Stellite 6 overlay on valve seats, delivering ANSI/FCI Class IV leakage performance—ideal for high-temperature, high-pressure, and abrasive media (e.g., crude oil, natural gas).
  • Optional Soft Seal: PTFE/RPTFE for low-temperature, non-abrasive media (e.g., purified natural gas), providing ANSI/FCI Class VI bubble-tight sealing (near-zero leakage).
• Valve Stem: A105 carbon steel or 17-4PH precipitation-hardened stainless steel, featuring an anti-blowout design to prevent ejection under pressure. Sealed with graphite-impregnated PTFE packing to minimize fugitive emissions (compliant with ISO 15848-1 Class BH).
• Flanges & Fasteners: Integral flanges machined to ASME B16.5 standards with Raised Face (RF) or Ring Type Joint (RTJ) finishes. Fasteners are ASTM A193 B7 alloy steel bolts and ASTM A194 2H nuts—offering high tensile strength (≥827MPa) and resistance to vibration-induced loosening.
• Gaskets: Spiral-wound gaskets (carbon steel with graphite filler) complying with ASME B16.20, ensuring leak-tight flange sealing under pressure and temperature fluctuations.

C. Connection & Operational Features

• Connection Type: Flanged (ANSI B16.5/ASME B16.47) as standard:
  • RF Flange: Suitable for Class 150-300 applications, providing a secure seal with spiral-wound gaskets—ideal for general industrial and natural gas distribution use.
  • RTJ Flange: Optional for Class 400-600 ultra-high-pressure systems (e.g., offshore oil platforms), using metal ring gaskets to withstand extreme pressure and prevent fugitive emissions.
• Drive Options:
  • Manual: Worm gear operation as standard for DN350, reducing torque requirements by 5–10 times and enabling single-person operation. A lever option is available for smaller sizes (DN100-DN200).
  • Pneumatic: Double-acting (compressed air for both opening and closing) or spring-return (auto-close/open on air supply loss) actuators. Cycle times for DN350 range from 20–40 seconds, making spring-return models ideal for emergency shutdowns in oil & gas pipelines.
  • Electric: Quarter-turn electric actuators with 4–20mA control signals, integrating with SCADA/DCS systems for remote monitoring and automation. IP67-rated enclosures ensure protection against dust and water, suitable for outdoor pipeline installations.
  • Hydraulic/Electro-Hydraulic: For ultra-high-torque applications (DN400+ or Class 600), providing precise control in heavy-industry settings (e.g., large-scale refineries).
• Functional Features:
  • Trunnion Mounted Design: Trunnion support distributes fluid pressure forces to bearings, eliminating seat deformation and reducing operational torque—critical for high-pressure Class 600 applications.
  • Bidirectional Sealing: Dual seats (upstream/downstream) enable reliable shut-off in both flow directions, simplifying pipeline design and eliminating installation direction constraints.
  • Anti-Static Device: A conductive spring connecting the ball, stem, and body dissipates static charges (resistance ≤10Ω)—essential for natural gas and oil applications to prevent spark-induced explosions.
  • Fire-Safe Design: Compliant with API 607, ensuring metal-to-metal sealing if non-metallic components (e.g., packing) degrade in a fire—preventing catastrophic media release.

D. Certifications & Compliance

• Design & Manufacturing Standards: API 6D (pipeline valves), API 608 (trunnion-mounted ball valves), ASME B16.34 (valve pressure-temperature ratings), ASME B16.5 (flange dimensions), API 598 (valve testing and inspection).
• Quality & Safety Certifications: ISO 9001 (quality management), CE (EU safety compliance), ATEX (optional for explosive gas atmospheres), IECEx (global hazardous area compliance).
• Performance Certifications: NACE MR0175 (optional for sour gas service with H₂S), ISO 15848-1 (fugitive emissions), ANSI/FCI Class IV (leakage).

III. Feature Description

A. Trunnion Mounted Design: Stability in High Pressure

• Pressure Force Distribution: Fluid pressure acts on the ball, but trunnions transfer these forces to robust bearings—preventing the ball from shifting into the valve seats. This eliminates seat deformation, a common issue in floating ball valves that increases operational torque and shortens seal life. In a DN350 Class 600 natural gas pipeline, this design maintains consistent sealing for 8–12 years, compared to 3–5 years for floating ball alternatives.
• Low Operational Torque: Trunnion support reduces friction between the ball and seats, lowering torque requirements by 40–50% compared to floating ball valves. A DN350 worm gear-operated model requires only 120 N·m of torque to operate—enabling manual control without specialized tools, even in high-pressure Class 600 systems.
• High-Pressure Resilience: The trunnion structure withstands Class 150-600 pressures without structural failure. In an offshore oil wellhead (Class 600), the valve handles 15MPa pressure spikes without leakage, outperforming floating ball valves that risk seat damage under such extreme conditions.

B. Carbon Steel Construction: Durability & Cost-Effectiveness

• High-Pressure Strength: Forged A105 and cast WCB carbon steel offer superior tensile and yield strength compared to low-grade materials, making them suitable for Class 150-600 high-pressure applications. In hydrostatic testing, the A105 body withstands 1.5× Class 600 pressure (22.5MPa) without deformation—ensuring safety in over-pressure scenarios (e.g., pump surges, pipeline blockages).
• Cost-Effectiveness: Carbon steel is more affordable than stainless steel (e.g., 304/316) while delivering comparable strength in non-corrosive oil & gas media. For large-scale oil pipeline projects with 100+ DN350 valves, this translates to 30–40% cost savings without compromising performance.
• Thermal Stability: Carbon steel retains its mechanical properties up to 425℃, making it suitable for heated media applications (e.g., crude oil heating systems, process steam lines) where lower-grade materials would soften or deform.
• Machinability & Weldability: A105/WCB’s excellent machinability enables precision CNC machining of critical surfaces (flanges, trunnion seats), ensuring dimensional accuracy. Its weldability allows for on-site modifications or repairs—critical for remote pipeline installations where valve replacement is time-consuming and costly.

C. Hard-Seal Performance: Reliability in Harsh Media

• High-Temperature Compatibility: Stellite 6 hard-facing retains its hardness (≥58 HRC) up to 425℃, making the valve suitable for high-temperature media (e.g., heated crude oil, natural gas, industrial steam) where soft seals (PTFE) would degrade rapidly. In a refinery’s hot oil line (380℃), the hard-seal valve operated reliably for 10 years, while a soft-sealed valve required quarterly seat replacements.
• Abrasive Media Resistance: The hard-sealed surface resists wear from particulate-laden media (e.g., natural gas with sand, crude oil with sediment). In a rural natural gas pipeline with fine dust particles, the valve withstood abrasive wear for 8 years, outperforming soft-sealed valves that failed within 2 years.
• Leak-Tight Sealing: The precision-ground metal-to-metal seal achieves ANSI/FCI Class IV leakage performance (≤0.1×DN mm³/min for gas), preventing fugitive emissions of oil and natural gas. This compliance with environmental regulations (e.g., EPA Methane Rules, EU Industrial Emissions Directive) avoids costly fines and reduces safety risks in residential or industrial areas.

D. Flanged Connection: Secure Installation & Maintenance Ease

• Leak-Tight Sealing: Bolted flanges distribute clamping force evenly across the gasket, ensuring a secure seal even under vibration or pressure fluctuations. In a DN350 oil pipeline, this design prevented fugitive emissions of crude oil, meeting strict safety standards for pipeline operations.
• Easy Installation & Retrofit: Flanges align with standard pipeline components, reducing installation time by 30% compared to welded valves. When upgrading an existing natural gas line, the valve can be installed without cutting the pipeline—minimizing downtime for utilities or oil & gas operators.
• Simplified Maintenance: Flanged valves can be disassembled for seat replacement or stem packing adjustment without removing the valve from the pipeline. In a refinery, this reduced maintenance time for DN350 valves from 8 hours (welded valves) to 2 hours—critical for continuous-process operations where unplanned downtime costs thousands of dollars per hour.

E. Multi-Drive Adaptability: Flexibility for Diverse Operations

• Manual Operation: Worm gear operators enable easy manual control of DN350 valves, ideal for remote pipeline sections or low-frequency use (e.g., emergency isolation in natural gas storage facilities). The ergonomic handwheel and 90-degree rotation reduce operator fatigue.
• Pneumatic Actuation: Spring-return pneumatic actuators provide critical fail-safe operation—auto-closing the valve if air supply fails, a non-negotiable feature for oil & gas pipelines where uncontrolled media release poses severe safety and environmental risks. Double-acting pneumatic actuators offer rapid cycle times for high-frequency applications (e.g., refinery process lines).
• Electric Actuation: Electric actuators with remote control capabilities integrate seamlessly with SCADA/DCS systems, enabling centralized monitoring and control. For cross-country oil pipelines or large refineries, this eliminates the need for on-site operators, reducing labor costs and safety risks associated with manual intervention.

IV. Manufacturing Processes

A. Material Inspection & Preparation

• Carbon Steel Verification: A105/WCB carbon steel billets are tested via spectral analysis to confirm chemical composition (C: 0.25–0.35% for A105, C: 0.25–0.35% for WCB) and ultrasonic testing (UT) to detect internal defects (porosity, cracks, inclusions). Mechanical testing (tensile strength, impact resistance, hardness) ensures compliance with ASTM standards, with results documented in Material Test Reports (MTRs) for full traceability.
• Heat Treatment: A105 billets undergo normalizing (900–950℃, air-cooled) to relieve forging stresses and improve machinability. WCB castings undergo annealing (850–900℃, slow-cooled) to reduce brittleness and enhance ductility.
• Hard-Seal Material Validation: Stellite 6 alloy is tested for hardness (≥58 HRC) via Rockwell testing and chemical composition (Co: 50–60%, Cr: 25–30%) to ensure wear resistance in abrasive oil & gas media.

B. Valve Body & Ball Fabrication

• Body Manufacturing: A105 valve bodies are produced via forging (for Class 300-600) to ensure material density and structural integrity—forging eliminates internal porosity, critical for ultra-high-pressure service. WCB bodies are produced via precision casting (for Class 150-300) to offer cost-effectiveness for medium-pressure applications. Forged/cast blanks are cleaned via shot blasting to remove scale and surface impurities.
• CNC Machining: Critical surfaces—flange faces, trunnion bearings, and seat pockets—are machined using 5-axis CNC centers. Flange faces are machined to ASME B16.5 flatness (≤0.05mm/m) and surface finish (Ra ≤3.2μm) for proper gasket seating. Trunnion seats are machined to a tolerance of ±0.02mm to ensure proper ball alignment. The valve’s internal flow path is polished to reduce friction and minimize pressure drop.
• Ball & Trunnion Fabrication: Solid carbon steel balls are precision-turned and ground using spherical grinders to achieve a surface finish of Ra ≤0.2μm—ensuring uniform contact with the hard seal. Trunnions (upper/lower) are integral to the ball, heat-treated for hardness (HRC 30–35) and machined to match the valve body’s bearing seats. For abrasive media, Stellite 6 is applied to the ball’s sealing surface via plasma transfer arc (PTA) welding, then ground to restore sphericity.

C. Seal & Actuator Integration

• Trunnion & Bearing Installation: Upper and lower trunnions are press-fitted into the valve body, with PTFE-impregnated bronze bearings to reduce friction. Bearings are lubricated with high-temperature grease (resistant to 200℃) to ensure smooth operation over thousands of cycles.
• Ball & Stem Assembly: The ground carbon steel ball is inserted into the body, and the stem is connected via a drive key—ensuring torque transfer during operation. The stem packing (graphite-PTFE) is installed in layers, with controlled compression (10–15% compression rate) to balance sealing performance and operational torque.
• Drive Mounting: Actuators (manual worm gear, pneumatic, electric) are mounted via an ISO 5211 adapter flange, with laser alignment to ensure coaxiality (stem runout ≤0.05mm)—preventing binding or premature wear. For pneumatic/electric actuators, limit switches are calibrated to trigger at fully open/closed positions, protecting seals from over-travel.

D. Quality Testing & Certification

• Hydrostatic Testing: Per API 598, the valve shell is tested at 1.5× rated pressure (e.g., 22.5MPa for Class 600) for 30 minutes—no leakage, sweating, or deformation is allowed. Seat testing is performed at 1.1× rated pressure (e.g., 16.5MPa for Class 600), with leakage measured via bubble counting (≤1 bubble per minute for Class IV).
• Pneumatic Testing: For natural gas service, the valve is tested with nitrogen at 0.6MPa to confirm airtight sealing—critical for preventing gas leaks in hazardous environments.
• Operational Testing: The valve is cycled 100 times (open/close) to verify smooth operation, consistent torque, and actuator response. Manual override (for pneumatic/electric models) is tested to ensure functionality during emergencies.
• Non-Destructive Testing (NDT): Welds (e.g., Stellite 6 seat welds) undergo liquid penetrant testing (PT) to detect surface cracks; the carbon steel body and trunnions are inspected via magnetic particle testing (MPI) to confirm structural integrity.
• Fugitive Emissions Testing: Per ISO 15848-1, the valve is tested for fugitive emissions at the stem and body-bonnet joint, meeting Class BH standards (≤100 ppmv for methane)—critical for natural gas applications.

E. Final Inspection & Documentation

• Visual Inspection: The valve is checked for surface defects (scratches, dents), proper marking (size, pressure rating, material, serial number), and compliance with ASME B16.34. Marking is permanent (laser-etched) for traceability in oil & gas pipeline systems.
• Documentation: Each valve includes an MTR for carbon steel, hydrostatic/pneumatic test reports, fugitive emissions test certificates, and compliance documents (API 6D, ISO 9001). For hazardous area applications, ATEX/IECEx certificates are provided to confirm compliance with global oil & gas safety standards.

V. Product Advantages

A. High-Pressure Reliability for Oil & Gas

B. Extended Service Life in Harsh Media

C. Cost-Effective Performance for Large-Scale Projects

D. Safety & Regulatory Compliance

E. Versatility Across Oil & Gas and Industrial Sectors

VI. Product Applications (Supplement)

A. Oil & Gas Industry (Supplement)

• Upstream Exploration: DN150~DN350 Class 400~600 valves control wellhead production fluid flow. Trunnion design resists high pressure from reservoir fluids, while anti-static features prevent sparks in explosive environments.
• Midstream Processing: DN200~DN400 Class 300~500 valves regulate oil-gas separation systems. Hard seal withstands corrosive well fluids, ensuring long-term leak tightness.

B. Power Generation

• Thermal Power Plants: DN250~DN350 Class 150~300 valves manage fuel oil/natural gas supply to boilers. Carbon steel’s high-temperature resistance adapts to boiler auxiliary systems, and full-port design reduces pressure loss.
• Waste-to-Energy Plants: DN100~DN200 Class 150~250 valves control syngas flow. Fire-safe design mitigates risks of syngas leakage and combustion.

C. Chemical & Petrochemical

• Basic Chemicals: DN100~DN300 Class 250~400 valves handle methanol, ethylene, and ammonia flow. Bidirectional seal simplifies pipeline layout, and NACE MR0175 compliance (optional) suits sour media.
• Coal Chemicals: DN200~DN400 Class 300~500 valves regulate coal gasification process fluids. Stellite 6 trim resists abrasive coal dust and high-temperature corrosion.

D. Municipal Energy

• City Gas Transmission: DN100~DN350 Class 150~300 valves adjust pressure in urban gas pipelines. Flanged connection enables quick maintenance, and anti-static design ensures safety in residential areas.
• Industrial Gas Supply: DN150~DN250 Class 250~300 valves control LPG/propane flow to factories. Soft seal (optional) achieves bubble-tight sealing, preventing gas leakage.

E. General Industrial Manufacturing

• Steel Mills: DN200~DN350 Class 150~300 valves manage blast furnace gas and cooling water flow. Carbon steel’s durability resists industrial dust and cyclic pressure.
• Paper & Pulp Mills: DN150~DN250 Class 150~250 valves regulate black liquor and steam flow. Hard seal withstands abrasive pulp residues and high-temperature media.

F. Marine & Offshore

• Offshore Platforms: DN200~DN350 Class 400~600 valves with RTJ flanges handle offshore oil/gas transfer. Corrosion-resistant carbon steel adapts to marine salt spray, and fail-safe actuators ensure emergency shutoff.

VII. Customization Solutions

• Material Upgrades: Opt for 316L stainless steel/2205 duplex steel for corrosive media (e.g., offshore saltwater, chemical acids); choose low-temperature carbon steel (LCB) for LNG vaporization systems (-46℃~425℃).
• Pressure & Seal Tuning: Upgrade to Class 900 (PN150) for ultra-high-pressure wellheads; switch to PTFE soft seals for bubble-tight Class VI leakage in purified natural gas pipelines.
• Drive & Control: Integrate smart electric actuators with Modbus TCP/IP for SCADA integration in cross-country pipelines; add hydraulic actuators for DN400+ valves in refinery high-torque scenarios.
• Industry-Specific Enhancements: Equip with NACE MR0175-compliant components for sour gas service (H₂S resistance); adopt RTJ flanges and anti-salt spray coating for offshore platforms; add low-temperature packing for cryogenic LNG applications.

  Share your media type, pressure/temp ranges, and automation demands—we’ll deliver a valve optimized for your workflow.