Specification

API 6D Gear-Operated Fully Welded Trunnion-Mounted Ball Valve

I. Product Overview

TIANYU API 6D gear-operated fully welded trunnion-mounted ball valve is a high-reliability flow control solution engineered for critical industrial pipelines. Crafted with forged carbon steel (A105) and stainless steel (F316), it features a fully welded body and trunnion-mounted (fixed ball) structure to eliminate leakage risks. Operating at -46℃~200℃ and Class 150~2500 pressure, it leverages gear operation for smooth control and integrates safety features like fire resistance and anti-blowout stems. Compliant with API 6D and ISO 14313, it is ideal for petroleum, natural gas, and underground pipelines where long-term sealing integrity and low maintenance are critical.

II. Key Attribute Parameters

Size Range: 2″~60″ (DN50~DN1500), covering small to large-diameter pipelines for diverse flow control needs, from gas distribution to oil transmission.
Pressure Range: Class 150~2500 (PN10~PN420), adapting to low to ultra-high pressure systems such as high-pressure gas lines and industrial process pipelines.
Temperature Range: -46℃~200℃, with A105 carbon steel handling low-temperature and ambient media, F316 stainless steel resisting corrosion in humid or chemical environments.
Material Configuration:
- Body: Forged carbon steel (A105) or low-temperature carbon steel, fully welded to avoid bolted connections—eliminating leakage points.
- Ball & Stem: F316 stainless steel, ensuring corrosion resistance and structural strength under media contact.
- Seat: PTFE (for general media) with pre-loaded springs, ensuring tight sealing even with pressure fluctuations.
Connection Type: Welded (BW) or flanged (RF/RTJ), with fully welded ends ideal for underground or leakage-sensitive pipelines.
Actuation: Gear-operated (manual), reducing torque for easy operation of large-diameter valves; optional electric/pneumatic actuators for automation.
Design & Test Standards: Follows API 6D, ISO 14313; testing complies with API 598 (hydrostatic strength at 1.5×rated pressure, sealing at 1.1×rated pressure).

Product Overview

III. Features Description

Fully Welded Body Integrity: The body uses welded joints instead of bolts, eliminating potential leakage points common in flanged valves. Spherical or cylindrical welded designs (1~2 seams) ensure uniform stress distribution, critical for underground pipelines where leakage is hard to detect.
Trunnion-Mounted Stability: The ball is fixed by upper and lower trunnions, transferring fluid pressure to trunnion bearings instead of the seat. This avoids ball displacement under high pressure, preventing seat wear and ensuring consistent sealing—vital for gas transmission.
Forged Material Reliability: Forged bodies eliminate casting defects like shrinkage cavities or cracks, ensuring structural strength in high-pressure environments. The uniform material density resists fatigue, extending service life to 30 years.
Gear Operation Convenience: The gear drive reduces operating torque by 50% compared to direct manual operation, allowing one person to control large-diameter (up to DN1500) valves. Its self-locking design prevents accidental rotation from pipeline vibration.
Safety & Maintenance Features: Integrates cavity pressure self-relief (avoids overpressure damage), fire-safe design (API 607), and anti-blowout stem (prevents ejection under extreme pressure). Emergency sealant injection ports enable on-site leak repair, reducing downtime.

IV. Manufacturing Processes

Forging & Welding: A105/F316 materials are forged to form dense blanks, then welded into spherical or cylindrical bodies using TIG welding. Ultrasonic testing verifies weld integrity, ensuring no hidden cracks.
Precision Machining: Ball and seat surfaces are CNC-machined to Ra ≤0.8μm for tight sealing. Trunnions are press-fitted and welded to the body, with bearing surfaces ground for smooth rotation.
Seat Assembly: PTFE seats are pre-loaded with springs to compensate for wear, ensuring consistent contact with the ball. Gear components are calibrated to 0.1~0.2mm meshing clearance for smooth torque transmission.
Testing:
- Hydrostatic Test: Body tested at 1.5×rated pressure (e.g., 6.4MPa for PN40) for 30 minutes; seat tested at 1.1×rated pressure to confirm no leakage.
- Fire-Safe Test: Exposed to 750℃ fire, then tested for post-fire sealing to meet API 607.
- Operation Test: 100+ open/close cycles verify gear smoothness and trunnion stability under pressure.

Valve Details

V. Product Advantages

Zero Leakage Assurance: Fully welded body and trunnion design eliminate leakage risks, reducing media loss by 99% compared to bolted valves—critical for gas or oil pipelines where waste is costly and hazardous.
Long Service Life: Forged materials and welded structure resist corrosion and fatigue, extending service life to 30 years—lowering replacement costs in remote or underground installations.
Underground Adaptability: Welded joints and corrosion-resistant materials avoid damage from soil moisture or burial, making them ideal for petroleum and natural gas underground lines.
Operational Efficiency: Gear drive simplifies operation of large valves, reducing labor costs. Full-bore design minimizes flow resistance, cutting pump energy consumption by 10~15% in transmission systems.
Global Compliance: API 6D certification ensures compatibility with international projects, from European gas networks to Asian oil fields, avoiding regulatory barriers.

Application

VI. Application Fields

Natural Gas Transmission: Controls flow in underground gas pipelines, with welded joints preventing leakage and corrosion resistance adapting to soil environments.
Petroleum Pipelines: Manages oil flow in long-distance transmission lines, leveraging high-pressure resistance (Class 2500) and low maintenance needs for remote installations.
Industrial Process Systems: Regulates flow in chemical or power plant pipelines, with PTFE seats ensuring compatibility with water, oil, and mild chemicals.
Low-Temperature Environments: Suitable for cold-region pipelines (-46℃), with low-temperature carbon steel body avoiding brittleness and ensuring structural stability.

TIANYU API 6D ball valve: 2″~60″, Class 150~2500, -46~200℃. Fully welded, gear-operated, trunnion-mounted. A105/F316, PTFE seat. Ideal for gas, oil, underground lines. Customizable: connection (welded/flanged), actuator for specific pipeline needs.