Stainless Steel Butterfly Valve
Corrosion-Resistant · DN50–DN600 · PN10/PN16 · Wafer / Lug
Reguvale's stainless steel butterfly valve is built for aggressive, hygienic and seawater services where a carbon-steel or ductile-iron body would corrode. The SS304 / SS316 / SS316L body and disc carry a PTFE or EPDM seat for bubble-tight shutoff, and the polished wetted surfaces suit hygienic-duty and chemical lines. We hold ISO 9001:2015 and an SGS-CSTC audit report; where a project calls for 3-A, NSF or FDA documentation, tell us the scope and we will confirm what can be supplied before you commit.
Standard sizes DN50–DN600 in pressure ratings PN10/PN16 are available in wafer and lug types, with manual lever, worm-gear, electric or pneumatic actuation. Each valve is pressure-tested at our Tianjin factory and can be supplied with EN 10204 3.1 material certificates and surface-treatment reports for audit compliance.
For seawater and offshore duty, SS316L with PTFE seat is the recommended combination; for potable water and CIP cleaning, EPDM seats are supplied with material datasheets for potable-water duty. Custom end connections (tri-clamp, weld, ANSI/DIN/JIS flange) are available on request.
Key Features
Corrosion Resistance
SS316L body and disc resist pitting and crevice corrosion in seawater, acids and chlorides far better than carbon steel or ductile iron.
Sanitary-Duty Materials
SS316L wetted parts with PTFE seats and electropolished surfaces are used on hygienic lines. We hold ISO 9001:2015 and supply EN 10204 3.1 mill certificates; where a project calls for 3-A, NSF or FDA documentation we will confirm exactly what can be supplied before you commit.
Bubble-Tight Shutoff
The concentric PTFE / EPDM-lined design is pressure- and seat-tested to ISO 5208 Rate A (EN 12266-1 Rate A) — bubble-tight against water, steam and compatible chemicals.
Flexible Actuation
Available with manual lever handle, worm gearbox, electric actuator, or pneumatic actuator for automated on/off and modulating control.
Full Traceability
EN 10204 3.1 mill certificates, hydrostatic test reports and surface-treatment records shipped with the order.
Low Cost of Ownership
Simple construction with few moving parts and a replaceable seat keeps lifecycle cost low even in aggressive service.
Technical Specifications
| Parameter | Specification |
|---|---|
| Body Material | SS304 / SS316 / SS316L (Electropolished optional) |
| Disc Material | SS304 / SS316 / SS316L |
| Seat Material | PTFE / EPDM / Viton(FKM) |
| Design Type | Concentric (Rubber/PTFE-Lined) |
| Size Range | DN50 – DN600 (2" – 24") |
| Pressure Rating | PN10 / PN16 |
| End Connection | Wafer / Lug (Tri-clamp & Weld on request) |
| Operation | Lever Handle / Worm Gearbox / Electric / Pneumatic |
| Temperature | EPDM: −20→+120°C | PTFE: −20→+200°C | Viton: −15→+200°C |
| Leakage Class | ISO 5208 Rate A / EN 12266-1 Rate A (bubble-tight) |
| Standards | EN 593 (product) · EN 558 (face-to-face) · ISO 5752 · MSS SP-67 · flange drilling to EN 1092-2 PN10/16 or ASME B16.5 Class 150 |
| Certification | ISO 9001:2015 (scope: manufacture of metal butterfly valves) · SGS-CSTC factory audit report · EN 10204 3.1 mill certificate. We do not hold API, CE, WRAS, NSF or 3-A certification — if your specification requires one, tell us the scope and we will confirm what can be documented before you commit. |
Stainless Steel or Ductile Iron?
Stainless costs more up front. It earns that back when the medium attacks the epoxy coating of a ductile iron body — or when the line has to stay clean.
| Aspect | Ductile iron GGG50 (epoxy-coated) | SS304 (CF8) | SS316 (CF8M) | SS316L |
|---|---|---|---|---|
| Relative cost, same size | Lowest | Low to mid | Mid to high | Highest |
| Neutral water, HVAC, general utility | Preferred — lowest cost | Works, usually unnecessary | Over-specified | Over-specified |
| Chlorides, brackish water, seawater | Not recommended — coating damage leads to pitting | Pitting risk above roughly 200–300 ppm chloride | Good — the standard choice | Best, especially at welds |
| Dilute acids, chemical dosing | No | Limited | Yes, medium dependent | Yes — preferred for aggressive duty |
| Hygienic / cleanable lines | Not suitable | Possible | Common | Common — lowest carbon, best finish |
| Weldability | Not applicable | Good | Good | Best — low carbon, no sensitisation at the weld |
Rule of thumb: neutral water in a plant room → buy ductile iron. Chlorides, chemicals, or a line that must be cleaned and inspected → buy stainless, and go SS316 or SS316L rather than SS304. The chloride figures are general guidance; send us the actual medium and concentration and we will confirm.
Seat Material Selection
The seat, not the body, usually decides whether the valve survives. Match it to the medium and the temperature.
| Seat | Temperature range | Best for | Avoid |
|---|---|---|---|
| EPDM | −20 to +120 °C | Potable water, cooling water, CIP cleaning, mild acids and bases | Oils, fuels and aromatic solvents |
| PTFE | −20 to +200 °C | Aggressive chemicals, steam, acid and alkali duty, hygienic lines | Highly abrasive slurries |
| Viton / FKM | −15 to +200 °C | Oils, solvents and hydrocarbons | Ketones, esters, hot water and steam |
| Metal seat (on request) | up to about +400 °C | High-temperature steam and process lines | Bubble-tight shutoff — metal seats are not drop-tight |
PTFE is the default for stainless bodies because it covers both the chemical duty and the hygienic duty. Where the line runs hotter than the seat allows, the seat is the item to change — a stainless body does not raise the temperature rating on its own.
Pressure Rating and Flange Drilling
Our stainless butterfly valves are rated PN10 and PN16, supplied in wafer and lug type from DN50 to DN600. PN is a 20 °C reference rating: the allowable pressure falls as the temperature rises, and how far it falls depends on the body and seat material, not on the PN number alone.
Two flange systems can be drilled on the same valve body, and they do not bolt together:
- EN 1092-2 PN10 / PN16 — European drilling, used on lines specified to EN 593 / EN 558.
- ASME B16.5 Class 150 — American drilling, with a different bolt circle and bolt count.
If you are not sure which applies to your line, see the DN / PN conversion and pressure rating chart, or send us the flange standard and we will confirm the drilling before you order.
What to Send Us for a Quote
These nine lines are enough for us to quote the right valve the first time, instead of trading questions for a week.
| # | Item | Why it matters |
|---|---|---|
| 1 | Size (DN or inch) | Sets the body, disc and actuator torque |
| 2 | Body and disc grade (SS304 / SS316 / SS316L) | The main cost driver after size |
| 3 | Seat material — or the medium and its temperature | We will select the seat if you give us the medium |
| 4 | Pressure rating (PN10 / PN16) | Wall thickness and test pressure |
| 5 | Flange standard (EN 1092-2 or ASME B16.5) | Different bolt pattern — the most expensive mix-up in valve buying |
| 6 | End connection (wafer / lug / flanged) | Lug and flanged allow dead-end service and easier removal |
| 7 | Operation (lever / gearbox / pneumatic / electric) | Drives the actuator, solenoid and limit-switch selection |
| 8 | Medium, concentration and working temperature | Decides body grade and seat compound |
| 9 | Quantity, destination port and documents required | Freight basis, packing, and what we have to certify |
Frequently Asked Questions
What grade of stainless steel is used for the body and disc?
Standard bodies and discs are SS304 or SS316, with SS316L available for weld-sensitive or low-carbon requirements. SS316L is preferred for chemical and seawater duty because of its higher molybdenum content and improved pitting resistance.
Which seat material should I choose for a stainless butterfly valve?
PTFE: Default for aggressive chemicals, steam and high temperatures up to +200°C, and food/pharma-compatible.
EPDM: Potable water, CIP cleaning and milder services up to +120°C.
Viton/FKM: Solvents and oils.
Can stainless steel butterfly valves be used for hygienic / sanitary service?
Yes. With PTFE seats, electropolished wetted surfaces and tri-clamp or weld ends, stainless butterfly valves are widely used in food, beverage, dairy and pharmaceutical lines. We hold ISO 9001:2015 and supply EN 10204 3.1 material certificates and surface-treatment reports; we do not hold 3-A, NSF or FDA certification, so where your specification requires one of those, tell us the scope and we will confirm what can be documented before you commit.
Is stainless steel worth it compared with ductile iron?
Only when the medium or the cleanliness requirement demands it. For neutral water and general utility duty, epoxy-coated ductile iron is cheaper and perfectly adequate. Stainless earns its price where chlorides, dilute acids or hygienic cleaning would attack a coated iron body — see the comparison table above. In those services, SS316 or SS316L is the usual choice; SS304 is rarely worth the small saving.
What is the maximum temperature of a stainless steel butterfly valve?
The seat sets the limit, not the body: EPDM to about +120 °C, PTFE and Viton/FKM to about +200 °C, and metal-seated versions higher on request. Fitting a stainless body does not by itself extend the temperature range.
Should I choose SS304, SS316 or SS316L?
SS304 for neutral water and mildly corrosive duty; SS316 when chlorides are present (brackish water, seawater, chemical dosing); SS316L where the valve will be welded into the line or the medium is aggressive, because its lower carbon content avoids sensitisation at the weld. Send us the medium with its concentration or chloride level and we will recommend.
What sizes and pressure ratings are available?
Stainless steel butterfly valves are supplied in wafer and lug type from DN50 to DN600, rated PN10 or PN16. Larger sizes are available in the ductile iron and carbon steel ranges — ask if your line size falls outside this range.
What decides the price of a stainless butterfly valve?
In order of impact: size, body and disc grade (SS316L costs more than SS304), seat material, end connection (lug costs more than wafer), and actuation — a pneumatic or electric package can cost more than the valve itself. Send the nine specification lines above and we will quote within 24 hours.
Applications & Use Cases
Chemical Processing
Acid, alkali and solvent lines where carbon steel would corrode.
Food & Beverage
CIP-cleanable sanitary lines with PTFE seats and polished surfaces.
Pharmaceutical
High-purity water and process streams with full material traceability.
Seawater & Offshore
SS316L + PTFE for cooling, ballast and utility systems.
Related Products
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DN50 – DN300 · PN10/16
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DN65 – DN1200 · PN10/25
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Helpful guides to help you specify and maintain stainless and butterfly valves.