Specification

API 6D Gear-Operated Trunnion-Mounted Ball Valve (Metal-to-Metal Seat)

I. Product Overview

TIANYU API 6D gear-operated trunnion-mounted ball valve is a high-performance flow control solution engineered for gas, oil, and industrial pipelines. Crafted with A105 carbon steel (body) and F316 stainless steel (ball, stem), it features a trunnion-mounted (fixed ball) structure and metal-to-metal seat design to handle high temperatures, high pressures, and abrasive media. Operating at -46℃~560℃ and Class 150~2500 pressure, it leverages gear operation for smooth control and integrates safety features like anti-blowout stems and fire resistance. Compliant with API 6D, ISO 14313, and ASME B16.5, it is ideal for gas transmission, oil refineries, and industrial process systems where zero leakage and long-term reliability 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 large oil lines.
Pressure Range: Class 150~2500 (PN10~PN420), adapting to low to ultra-high pressure systems such as high-pressure gas transmission and industrial process pipelines.
Temperature Range: -46℃~560℃, with F316 stainless steel resisting corrosion and high-temperature oxidation, A105 carbon steel suitable for general industrial environments.
Material Configuration:
- Body: A105 (cost-effective for gas/oil) or F316 (corrosion resistance for chemicals), forged to eliminate casting defects like cracks or pinholes.
- Ball & Stem: F316 stainless steel, ensuring strength and corrosion resistance under high pressure and media contact.
- Seat: Metal-to-metal (tungsten carbide coated via HVOF) with hardness up to HRC72, or PTFE for general media—both achieving tight sealing.
Connection Types: Flanged (RF/RTJ per ASME B16.5) or welded (BW), with flanged options enabling easy disassembly and welded for leakage-sensitive systems.
Actuation: Gear-operated (manual), reducing torque to allow smooth 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

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—critical for gas pipelines where leakage risks safety.
Metal-to-Metal Sealing: Seats and balls are coated with tungsten carbide via HVOF (High Velocity Oxy Fuel) spraying, achieving hardness up to HRC72 and bonding strength ≥10,000Psi. This resists wear from abrasive media (e.g., gas with particles), ensuring zero leakage even after 10,000+ cycles.
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 & Reliability: Integrates anti-blowout stem (prevents ejection under extreme pressure), cavity pressure self-relief (avoids overpressure damage), and fire-safe design (API 607) to maintain sealing if soft components fail in a fire. Emergency sealant injection ports enable on-site leak repair.
Forged Structure Integrity: Forged bodies (instead of cast) eliminate internal defects, enhancing structural strength in high-pressure environments. This avoids leakage points common in cast valves, making them ideal for critical gas/oil lines.

IV. Manufacturing Processes

Forging & Material Preparation: A105/F316 materials are forged to form dense, defect-free bodies. Ultrasonic testing detects hidden cracks, ensuring structural integrity for high-pressure use.
Precision Machining: Ball and seat sealing surfaces are CNC-machined to Ra ≤0.8μm. Metal-to-metal seals undergo “one-to-one” grinding to ensure perfect contact, while PTFE seats are pre-loaded with springs for consistent pressure.
HVOF Coating (Metal Seats): Tungsten carbide is sprayed onto seat and ball surfaces at high velocity, forming a 0.3~0.5mm thick coating with HRC68~72 hardness. This process ensures uniform coverage and strong bonding to resist wear.
Assembly & Testing:
- Gear components are calibrated to 0.1~0.2mm meshing clearance for smooth torque transmission; trunnions are press-fitted and welded to the body for stability.
- 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℃~1000℃ fire, then tested for post-fire sealing to meet API 607.

Valve Details

V. Product Advantages

Zero Leakage Assurance: Trunnion design and metal-to-metal sealing eliminate internal leakage; forged bodies avoid casting defects, reducing external leakage risks—critical for gas transmission where even minor leaks are hazardous.
Long Service Life: Tungsten carbide coatings resist wear, and F316 stainless steel resists corrosion, extending service life to 20~30 years—lowering replacement costs in remote or hard-to-maintain pipelines.
High-Pressure & Temperature Adaptability: Handles Class 2500 pressure and 560℃ temperatures, outperforming standard valves in high-temperature industrial processes like oil refining.
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 circulation systems.
Global Compliance: API 6D and ASME B16.5 certification ensures compatibility with international projects, from European gas networks to North American oil pipelines, avoiding regulatory barriers.

Application

VI. Application Fields

Gas Transmission: Controls natural gas flow in long-distance pipelines, with metal-to-metal seals resisting particle wear and forged bodies ensuring safety in high-pressure (Class 900+) environments.
Oil Refining: Manages high-temperature oil and process media, leveraging high-temperature resistance (up to 560℃) and corrosion resistance to handle hydrocarbons and additives.
Industrial Process Systems: Regulates flow in chemical plants or power plants, with F316 options resisting nitric acid, acetic acid, and other corrosive media.
Abrasive Media Handling: Suitable for gas or oil with small particles (e.g., coalbed methane), as tungsten carbide seats avoid seal damage from abrasion.

TIANYU API 6D ball valve: 2″~60″, Class 150~2500, -46~560℃. Gear-operated, trunnion-mounted. Metal-to-metal seal, forged A105/F316. Ideal for gas, oil, chemicals. Customizable: seat (PTFE/metal), connection (flanged/welded) for specific media.