904L Austenitic Stainless Steel Worm Gear API609 Flanged PTFE Lined Butterfly Valve

Product Overview

The 904L Austenitic Stainless Steel Worm Gear API609 Flanged PTFE Lined Butterfly Valve is a high-grade ultra-corrosion-resistant industrial shutoff and regulating valve manufactured in strict accordance with American API609 industrial standards. The entire valve body and key structural parts are forged and cast from premium 904L super austenitic stainless steel (UNS N08904), a high-nickel, high-molybdenum and copper-containing alloy material with far stronger chemical stability than ordinary 304 and 316L stainless steel. Adopting standard ASME flanged connection structure and classic worm gear manual transmission mode, the valve features labor-saving operation and self-locking positioning.

The inner cavity and valve disc are fully lined with high-purity PTFE fluorine material, forming a dual anti-corrosion protection system of 904L metal base + fluorine lining isolation. It perfectly adapts to extreme harsh working conditions such as strong acid, high chlorine ion, salt water and organic solvent corrosion that ordinary valves cannot withstand. All dimensions, pressure grades and factory tests comply with ASME B16.5, ASME B16.10 and API598 specifications. With reliable bidirectional zero leakage performance and stable long-term operation, it is widely used in fine chemical, pharmaceutical, desulfurization, seawater treatment and high-corrosion industrial pipeline engineering projects.

Core Product Features

1. Strict API609 American Standard Compliance
Designed, produced and inspected fully in accordance with API609 Category B butterfly valve specifications, matching ASME B16.5 flange dimension, ASME B16.10 face-to-face length and API598 hydrostatic test standards. All finished products pass 100% shell pressure test and sealing performance test, fully meeting international high-standard chemical engineering acceptance and third-party inspection requirements.

2. Premium 904L Austenitic Stainless Steel Body
Adopts imported standard 904L super austenitic stainless steel integral molding, featuring low carbon, high nickel and high molybdenum alloy composition. It has excellent resistance to sulfuric acid, phosphoric acid, acetic acid and other non-oxidizing acids, as well as outstanding anti-chloride pitting and stress corrosion performance. It solves the corrosion failure problem of 316L stainless steel valves in ultra-harsh corrosive environments.

3. Dual 904L & PTFE Full Anti-Corrosion Structure
The metal base is 904L anti-corrosion stainless steel, and the inner wall and valve disc are fully lined with high-density PTFE/FEP fluorine material. The dual-layer anti-corrosion structure completely isolates all strong corrosive media, realizing universal corrosion resistance for almost all acid, alkali, salt and solvent working conditions, with ultra-long service life.

4. Worm Gear Labor-Saving Self-Locking Operation
Equipped with high-precision worm gear transmission mechanism, the turbine deceleration structure greatly reduces manual operating torque, realizing labor-saving opening and closing. The built-in mechanical self-locking function fixes the valve plate at any opening angle, preventing displacement and jitter caused by medium impact, ensuring accurate and stable pipeline flow regulation.

5. Standard ASME Flange Connection Design
Adopts ANSI standard heavy-duty flanged connection, with accurate flange hole position and uniform specification. It can be perfectly matched with American standard industrial pipelines, featuring firm bolt connection, strong vibration resistance and no loosening or leakage during long-term continuous operation of high-corrosion medium pipelines.

6. ANSI Class VI Zero Leakage Sealing
Adopts high-elastic fluorine rubber soft sealing pair, with excellent compression resilience and fitting performance. It achieves bubble-tight bidirectional zero leakage shutoff, effectively preventing leakage of toxic, corrosive and valuable chemical media, ensuring pipeline operation safety and production economy.

7. Wide Temperature & Working Condition Adaptability
The composite structure of 904L stainless steel and PTFE lining maintains stable performance in the temperature range of -20℃ to 180℃. It resists low-temperature brittleness and high-temperature aging, and can operate stably for a long time in high-chlorine, acid-base alternating and complex harsh industrial environments.

Technical Specifications

Installation, Operation & Maintenance Notes

1. Standard Operation Guidelines
This API609 904L fluorine-lined butterfly valve is suitable for full open/closed isolation and stable flow regulation of ultra-corrosive medium pipelines. Long-term ultra-small opening throttling is prohibited to prevent high-speed corrosive medium scouring on the fluorine-lined surface. Strictly operate within rated pressure and temperature range to avoid lining aging and peeling failure.

2. Standard Flange Installation Requirements
Install the valve on the straight pipe section of industrial pipelines, keep away from pump outlets and elbow turbulent areas. Align the valve ASME standard flange with the pipeline flange accurately, install anti-corrosion gaskets, and tighten bolts diagonally and evenly to ensure uniform stress. Completely clean pipeline welding slag and sharp impurities before installation to prevent scratching the fluorine-lined anti-corrosion layer.

3. Worm Gear Transmission Maintenance
Regularly inject anti-rust and lubricating grease into the worm gear box to ensure flexible and labor-saving manual operation. Check the self-locking function regularly to avoid automatic rotation of the valve plate caused by medium pressure impact. Avoid violent forced twisting of the handwheel to prevent gear structural damage.

4. Daily Anti-Corrosion Inspection & Maintenance
Regularly check the flange connection tightness and sealing surface wear status. Although 904L material has excellent anti-corrosion performance, regular surface cleaning is required to avoid chemical crystallization scaling. Replace aging sealing accessories in time after full pipeline depressurization and medium drainage to maintain zero leakage performance.

Wide Application Scenarios

• Fine Chemical Industry: Sulfuric acid, acetic acid, phosphoric acid and other strong acid corrosive medium transmission pipeline systems

• Pharmaceutical & Biochemical: Pharmaceutical intermediate liquid, biochemical waste liquid and high-purity corrosive process pipeline isolation valves

• Environmental Protection & Desulfurization: Power plant flue gas desulfurization slurry, high-chlorine wastewater and corrosive sewage treatment systems

• Seawater & Salt Water Treatment: Seawater desalination, circulating salt water and high-chloride medium anti-corrosion pipeline equipment

• High-End Chemical Projects: Organic solvent, corrosive chemical raw material and complex harsh medium pipeline control systems

Product Competitive Advantages

✅ Genuine API609 Standard Compliance — Fully compliant with American industrial standards, compatible with global ASME standard flange pipeline systems.

✅ 904L Super Austenitic Stainless Steel — High-alloy anti-corrosion material, far superior to 316L, suitable for strong acid and high-chlorine extreme corrosive environments.

✅ Dual Heavy-Duty Anti-Corrosion Design — 904L metal base + full PTFE lining, double-layer protection for ultra-long service life in harsh chemical working conditions.

✅ Worm Gear Labor-Saving Self-Locking — Stable manual operation with accurate positioning, no jitter and displacement, ensuring precise flow control.

✅ ANSI VI Zero Leakage Performance — High-elastic fluorine sealing pair, bidirectional tight shutoff, no corrosive medium leakage risk.

✅ Extreme Working Condition Adaptability — Excellent resistance to acid, alkali, chloride and stress corrosion, covering most high-corrosion industrial scenarios.

Order & Certification Information

MOQ: 1 Unit
Production Lead Time: 12–25 working days for standard specifications
Supporting Documents: EN10204 3.1 904L Material Certificate, API609 Test Report, API598 Inspection Report, ISO9001 Quality Certificate
Export Packaging: Internal anti-rust & lining protection + Plastic wrap + Reinforced fumigation-free wooden export case
Warranty Service: 12-month quality warranty + lifelong professional after-sales technical support

Contact Us for customized sizes, special pressure grades and bulk preferential prices of 904L Austenitic Stainless Steel Worm Gear API609 Flanged PTFE Lined Butterfly Valves.

What Is an API Butterfly Valve

An API Butterfly Valve is a quarter turn valve used to control, regulate, or isolate the flow of liquids, gases, and slurries in industrial piping systems. The valve features a rotating disc positioned inside the flow passage, which opens or closes as the shaft turns. Designed and manufactured in accordance with API standards, it provides reliable sealing and structural integrity. Its compact construction and simple operating mechanism make it suitable for oil and gas, chemical, power generation, and water treatment applications.

Why the API Butterfly Valve Matters

An API Butterfly Valve is important because it offers efficient flow control while occupying less space than many other valve types. API standards help ensure consistent quality, dependable sealing, and reliable operation under demanding service conditions. The valve supports both isolation and throttling functions and can be equipped with various actuation methods. Its versatility and durability help maintain process safety and improve the overall efficiency of industrial systems.

Common Product Types by API Butterfly Valve

Common product types include concentric butterfly valves, double offset butterfly valves, and triple offset butterfly valves. Soft seated valves are widely used for water and general industrial service, while metal seated designs are suitable for elevated temperatures and abrasive media. Manual, electric, pneumatic, and gear operated versions are available to meet different operational requirements. Various body materials and seat configurations allow the valve to adapt to diverse process environments.

Key Advantages of API Butterfly Valve

The valve offers lightweight construction, compact dimensions, and low operating torque. Quarter turn movement enables fast opening and closing, improving response time and process control. API compliant construction provides dependable sealing and extended service life. Installation and maintenance are straightforward, and the valve can be customized with different materials and actuation methods to perform effectively in corrosive, high temperature, and demanding industrial applications.

API Butterfly Valve Machine Structure and Core Stations

Manufacturing begins with casting or forging the body, disc, and shaft components using suitable materials. Core stations include heat treatment, CNC machining of sealing surfaces, shaft bores, and disc profiles to ensure dimensional accuracy. Assembly stations install the shaft, seat, bearings, seals, and operating mechanism. Final stages involve pressure testing, surface treatment, cleaning, marking, and packaging to ensure smooth operation, reliable sealing, and compliance with industrial quality requirements.