Semi-Lug Butterfly Valve | WCB Body, CF8 Disc, Viton Seat | Worm Gear DN150 10K

Product Overview

The semi-lug body features two threaded inserts on the downstream side, while the upstream side remains wafer-style. This design allows the valve to be bolted directly to the downstream flange, enabling dead-end service—the valve can hold full pressure on one side when installed at a pipeline end without requiring a mating counterflange on the other side.Unlike a full-lug butterfly valve which has lugs on both sides, the semi-lug design reduces weight, saves material cost, and lowers installation complexity while still offering end-of-line isolation capability for one side of the system. This makes it ideal for isolation points, system expansion connections, and maintenance shut-offs where only one side of the valve requires independent removal.

The WCB body conforms to ASTM A216 Grade WCB, the default cast carbon steel for valve bodies in standard industrial  service . It offers a temperature range of -29°C to 425°C, a minimum tensile strength of 485 MPa, and excellent weldability, making it well-suited for oil and gas pipelines, refineries, chemical plants, and power generation facilities where both strength and cost-effectiveness are required.

The CF8 disc (ASTM A351 Grade CF8, the cast equivalent of wrought 304 stainless steel) contains approximately 18% chromium and 8% nickel, providing good corrosion resistance in water, air, mild chemicals, and many industrial fluids.The CF8 disc offers excellent balance of corrosion resistance, strength, and cost-effectiveness, with a smooth surface finish that minimizes flow resistance and prevents media buildup.For more aggressive media containing chlorides, an upgrade to CF8M (AISI 316) is available upon request.

The Viton seat (fluorocarbon rubber, FKM) delivers outstanding performance in demanding conditions. Standard grades operate up to +204°C, with excellent resistance to hydrocarbons, fuels, oils, acids, solvents, ozone, and UV degradation.Viton offers stronger chemical resistance than NBR or EPDM, particularly in hydrocarbon and acid service, making it the preferred seat material for oil & gas, chemical processing, and high-temperature industrial systems where aggressive media are present.

The worm gear operator provides smooth, high-torque manual control with a self‑locking mechanism and a built‑in visual position indicator, making it particularly suitable for DN150 (6-inch) applications where a hand lever would require excessive effort. Operation of this DN150 valve is smooth and low-effort, even under differential pressure, thanks to the gear reduction ratio. The worm gear is self-locking—the disc holds its position securely without drifting once set—enhancing operational safety. The cast-iron gear housing is sealed to protect internal components, ensuring long-term reliability in industrial environments. For automated applications, the ISO 5211 top flange enables direct mounting of electric or pneumatic actuators without custom brackets.

Tianjin Worlds Valve Co., Ltd. operates under an ISO 9001 certified quality management system and can supply products with CE, UKCA, WRAS, and ACS certifications upon request.We are a direct China-based OEM/ODM manufacturer producing valves strictly to customer specifications, providing full documentation (mill test reports and pressure test reports) with every order.

 

Introduce:

Semi-Lug Butterfly Valve | WCB Body, CF8 Disc, Viton Seat | Worm Gear DN150 10K

Tianjin Worlds Valve Co., Ltd. – Your Reliable Source for Durable, Cost-Effective Flow Control

CBF02-TL01 - Detailed Product Info

Key Features & Advantages

1. Semi-Lug Body–Downstream Dismantling & Dead-End Service

• Threaded lugs on the downstream side allow bolted connection to a single flange for end-of-line isolation.

• Upstream side is wafer-style, reducing weight and material cost compared to full-lug valves.

• Ideal for isolation points, system expansion connections, and maintenance shut-offs where only one side requires independent removal.

• Flange drilling compatible with JIS 10K, EN 1092 PN10/PN16, and ANSI B16.5 Class 150.

 

2. WCB Carbon Steel Body–High Strength & Wide Temperature Range

• ASTM A216 Grade WCB, the standard cast carbon steel for valve bodies in industrial service.

• Temperature range: -29°C to 425°C; tensile strength: min 485 MPa.

• Excellent weldability and impact resistance for demanding oil/gas, chemical, and power applications.

• Epoxy coating (any RAL color) provides external corrosion protection.

 

3. CF8 (304) Stainless Steel Disc–Corrosion Resistant & Cost-Effective

• CF8 (ASTM A351 Grade CF8) contains ~18% Cr and 8% Ni for good corrosion resistance in water and mild chemicals.

• Smooth surface finish minimizes flow resistance and prevents media buildup.

• Upgrade to CF8M (316) available for seawater, high-chloride, or acidic environments.

 

4. Viton (FKM) Seat–High-Temperature & Chemical Resistance

• Excellent resistance to hydrocarbons, fuels, oils, acids, solvents, ozone, and UV.

• Operating temperature up to +204℃ (standard grade), short-term exposure up to +250℃.

• Superior chemical resistance compared to NBR or EPDM, ideal for aggressive media.

 

5. Worm Gear Operator–Smooth, Self-Locking Manual Control

• High gear reduction provides effortless operation for DN150 valves, even under differential pressure.

• Self-locking mechanism holds disc at any position without drifting.

• Visual position indicator allows quick valve status verification.

• Cast-iron sealed gear housing protects internal components for long-term reliability in industrial environments.

 

6. Fully Customizable OEM/ODM Solution

• Body materials: WCB (standard), ductile iron, CF8, CF8M.

• Disc materials: CF8 (standard), CF8M, duplex, super duplex, aluminum bronze.

• Seat materials: Viton (standard), EPDM, NBR, PTFE.

• Pressure ratings: JIS 10K (standard), PN10, PN16, Class 150.

• Flange standards: JIS B2220 10K, EN 1092, ANSI B16.5, AS2129.

• Operation: Worm gear (standard), hand lever, electric actuator, pneumatic actuator (ISO 5211 top flange available).

• Certifications: ISO 9001, CE, UKCA, WRAS, ACS available upon request.

Standard:

 

Why Choose Tianjin Worlds Valve?

1. Direct OEM/ODM Manufacturer–We produce in our own ISO 9001 certified factory, not only a trading company. Every semi-lug butterfly valve is manufactured to your exact specifications.

2. Material & Design Flexibility–WCB body, CF8 disc, Viton seat, worm gear operator, JIS 10K rating—all can be tailored to your specific media, temperature, and pressure requirements.

3. Semi-Lug Design Expertise–Our semi-lug construction offers the perfect balance of dead-end service capability (on the downstream side) and weight/cost savings (wafer-style upstream). Perfect for systems requiring downstream dismantling.

4. Certified Quality–ISO 9001 certified with CE, UKCA, WRAS, and ACS certifications available upon request to meet global market requirements.

5. Full Documentation–Material certificates (mill test reports) and pressure test reports provided with every order.

6. Global Export Experience–Supplying valves to over 50 countries with reliable logistics and technical support.

Conclusion:

We invite you to contact us for a competitive quotation or to arrange a visit to our factory. Our engineering team is ready to discuss your specific media, temperature, and pressure requirements—whether you need a standard DN150 JIS 10K semi-lug butterfly valve or a fully customized solution with special materials or actuation.