Precision Casting Valve Plug for Plug Valves

The Precision Casting Valve Plug for Plug Valves is a high-precision component designed for quick-acting flow control in industrial pipelines, particularly the handling of slurries, viscous fluids, and abrasive media. Manufactured from 316L (UNS S31603), 2205 duplex (UNS S32205), or hard-faced alloys like Stellite® 6 via investment casting, these plugs feature tapered or straight-sided geometries optimized for minimal torque and positive shutoff.

Engineered with tight clearance fits (0.02-0.05mm) and surface finishes (Ra ≤ 1.6μm), the plugs meet API 599 and BS 5153 standards, ensuring reliable operation in pressures up to 100 bar (1,450 PSI) and temperatures from -50°C (-58°F) to 600°C (1,112°F).

The valve plug rotates to change the opening and closing state of the fluid passage. Plug valves offer excellent sealing and fluid control capabilities, making them particularly suitable for applications requiring frequent switching or handling media containing impurities.

Wear-Resistant Construction: Stellite® 6 hardfacing on plug faces and edges provides superior abrasion resistance in slurries containing up to 15% solids (≤ 100μm diameter), extending service life by 50% compared to uncoated plugs.

Multi-Seal Compatibility: Designed for elastomeric (EPDM, NBR) or metal-to-metal seals, with optional O-ring grooves and lubrication ports for low-friction operation in high-viscosity fluids (up to 50,000 cP).

Precision Machining: CNC-machined tapers (1:12 or 1:8) ensure uniform seating pressure, with hardness testing (30-45 HRC) confirming resistance to galling and seizure in high-cycle applications.

Anti-Static Design: Conductive coatings on plug surfaces prevent electrostatic buildup in hydrocarbon services, compliant with API 607 anti-static requirements for flammable media.

The plug inside the plug valve is the key component of the valve, and there is usually an opening (or channel) in the middle of the plug. By rotating the plug, the opening can be aligned or staggered with the pipeline, thus realizing the opening or closing of the fluid. When the opening is aligned with the pipe, the fluid can pass through; when the plug is rotated 90 degrees and the opening is perpendicular to the pipe, the fluid is blocked.

Plug valves are most suitable for use as shut-off and flow diversion devices. Through special structural designs and modifications to the shape of the plug channel, they can also be adapted for throttling applications. These valves are primarily used in industries such as chemical, petrochemical, and power generation.

Mining & Minerals: Used in ore processing lines to control abrasive slurries, with Stellite®-faced plugs enduring erosion from silica and iron ore particles.

Pulp & Paper: Deployed in stock preparation systems for handling fibrous slurries, where the plug’s tapered design prevents fiber entanglement and ensures rapid shutoff.

Chemical Process Industry: Integral to batch processing systems for corrosive liquids and polymers, with duplex 2205 plugs resisting stress corrosion in chloride-rich environments.

Lubrication Systems: Forms the core of grease and oil control valves in heavy machinery, with 316L plugs offering corrosion resistance and easy maintenance via removable gland packing.

Q: What is the typical torque required to operate these plugs?

A: For a 2-inch plug, torque ranges from 10-30 Nm for elastomer seals; metal seats require 20-50 Nm, depending on pressure and media viscosity.

Q: Can the plug be repaired after surface wear?

A: Minor wear can be restored via grinding and re-hardfacing; major damage requires replacement, with interchangeable plugs available for quick turnaround.

Q: How does the plug design prevent fluid leakage during operation?

A: The tapered plug creates a wedging action against the seat as pressure increases, providing self-energizing sealing that tightens with higher differential pressure (up to 50 bar/725 PSI).