Metal Seated Ball Valve

Metal seated ball valve is a type of ball valve where both the ball and the seat surfaces are made of metal (instead of soft materials like PTFE, nylon, or other polymers). These valves are specially designed to withstand high temperatures, abrasive media, and severe service conditions.

1. Structure Of Metal Seated Ball Valve

Body: Typically forged or cast steel, stainless steel, or other high-strength alloys.
Ball: Precision-machined and coated with hard materials (such as tungsten carbide, chromium carbide, stellite) to resist wear and erosion.
Seat: Metal-to-metal contact seat, also hardened or coated for durability.
Stem: Connects the ball to the actuator or handle; often fitted with high-strength bearings and seals.
Sealing system: Uses spring-loaded or fixed metal seats, sometimes combined with graphite seals for tight shutoff under high temperature.

2. Advantages Of Metal Seated Ball Valve

High temperature resistance: Can operate up to 500–700°C (sometimes higher with special alloys).
Abrasion resistance: Suitable for slurry, powders, ash, and other abrasive media.
Fire-safe design: No reliance on soft seats, so performance is not compromised in fire conditions.
High durability: Long service life under severe conditions due to hardened seating surfaces.
Bubble-tight shutoff: Advanced hard-coating and precise lapping allow tight sealing even in metal-to-metal contact.
Corrosion resistance: Available with materials and coatings suited for corrosive fluids.

3. Applications Of Metal Seated Ball Valve

Metal seated ball valves are widely used in severe service industries, including:
Power plants: Steam isolation, boiler feedwater, high-temperature gas service.
Oil & Gas: Refinery, coking units, catalyst handling, abrasive slurries.
Chemical & Petrochemical: Corrosive and high-temperature media.
Mining and minerals: Slurry, tailings, and abrasive solid handling.
Pulp & Paper: Black liquor, green liquor, and other abrasive process streams.
Industrial gas: High-temperature hydrogen, oxygen, and other process gases.

The differences between metal seated ball valves and soft seated (soft seal) ball valves:

1. Structure

Feature	Metal Seated Ball Valve	Soft Seated Ball Valve
Seat Material	Metal-to-metal contact (hardened alloys, coatings like tungsten carbide, stellite, Cr carbide)	Soft materials (PTFE, PEEK, Nylon, Devlon, etc.)
Sealing	Precision-lapped metal surfaces, sometimes assisted with springs	Elastic deformation of soft seat for bubble-tight shutoff
Temperature Seals	Often use graphite or metal gaskets	Polymer-based seals

2. Performance / Characteristics

Aspect	Metal Seated	Soft Seated
Temperature Range	Up to 500–700 °C (special designs even higher)	Typically –29 °C to ~200–260 °C (depending on seat material)
Pressure Capability	Very high, suited for critical service	Moderate to high, depending on design
Sealing Tightness	Good, but sometimes Class IV–V leakage allowed (not always bubble-tight)	Excellent bubble-tight shutoff (Class VI)
Wear / Abrasion Resistance	Excellent, handles slurry, ash, powders	Poor, soft seats wear quickly with solids or abrasive fluids
Fire Safety	Naturally fire-safe	Requires fire-safe design (soft seat may burn/damage)
Maintenance	Longer service life in severe duty but harder to repair	Easy to maintain but shorter life in harsh service