Duplex 2205 Stainless Steel Swing Check Valves

High Strength (≥450 MPa Yield): Approximately twice the yield strength of 316/316L, providing structural integrity in high-pressure pulsating flow conditions.

Superior Chloride SCC Resistance: Outstanding resistance to chloride-induced stress corrosion cracking, performing reliably in high-chloride environments where 304/304L and 316/316L fail.

Excellent Pitting and Crevice Corrosion Resistance: PRE (Pitting Resistance Equivalent) ≥ 34 for S31803 and ≥ 35 for S32205, providing reliable service in seawater and aggressive chemical media.

NACE MR0175 / ISO 15156 Compliant: Fully qualified for sour service (H₂S) applications up to 232°C (450°F), with documented HIC and SSC test reports available.

Automatic Operation: Swing disc opens with forward flow, closes by gravity and reverse flow – no external power required.

Low Pressure Drop: Streamlined body design and angled seat provide minimal pressure drop across the valve.

Multiple Disc Types: Available with single disc, dual disc, or dual plate configurations for different flow characteristics.

Multiple End Connections: Flanged (ASME B16.5), wafer, lug, and butt weld (BW) connections.

Full Range of Types: Swing check (2″–48″), tilting disc check (2″–24″), nozzle check (2″–36″), and silent check (1/2″–12″).

Pressure Ratings: Available in Class 150, 300, 600, 900, 1500, and 2500 (PN16 to PN420).

Temperature Range: Suitable for -46°C to 300°C (-50°F to 572°F) depending on seat material.

International Certifications: Valves can be certified by ABS, BV, DNV, LR, GL, RINA, CCS, KR, and NK, and comply with API 6D, API 594, ASME B16.34, NACE MR0175, and NORSOK M-650 standards.

Raw Material Selection: High-quality Duplex 2205 (S31803/S32205) stainless steel from certified mills (Outokumpu, Sandvik, POSCO, Baosteel) with certified chemical composition and ferrite/austenite balance verification.

Casting/Forging: Valve body and bonnet cast (CF3M equivalent) or forged to shape with strict temperature control.

Heat Treatment – Solution Annealing: Valve components solution annealed at 1040–1120°C followed by water quenching to restore balanced duplex microstructure.

Ferrite Content Verification: 35–65% ferrite documented.

Machining: CNC lathes and machining centers produce precise dimensions – seat ring cavity, disc arm pivot points, hinge pin bores, flange faces, and bolt holes.

Disc Machining: Disc machined to precise dimensions for proper seating.

Seat Hardfacing (if specified): Stellite overlay on seat ring.

Assembly: Body, seat ring, disc, hinge pin, bonnet, gasket, and bolting assembled.

Testing: Hydrostatic shell test, high-pressure seat test, low-pressure seat test, disc movement verification.

Marking: Laser engraved with size, pressure, material, heat number, API 6D, and NACE markings.

Pressure Testing: 100% hydrostatic shell test (1.5× rated pressure), high-pressure seat test (1.1× rated pressure), low-pressure air seat test (80 psi, bubble-tight).

Material Verification: PMI 100% for body, bonnet, disc, hinge pin.

Ferrite Content Measurement: 35–65% ferrite documented.

Dimensional Inspection: Face-to-face, flange dimensions, disc alignment.

Disc Travel Verification: Disc opens fully at design flow.

NACE Compliance: Hardness verification for sour service.

Third-Party Inspection: ABS, BV, DNV, LR, TUV on customer request.

Offshore Oil & Gas Platforms: Pump discharge check valves, seawater lift pump protection, produced water lines (ABS/BV/DNV/LR certified, NORSOK M-650 qualified).

Seawater Systems: Cooling water pump discharge, firewater system check valves, ballast water treatment, intake lines.

Desalination Plants: High-pressure reverse osmosis (HPRO) feed pump check, brine discharge lines.

Flue Gas Desulfurization (FGD): Slurry lines, absorber tower pump discharge.

Chemical Processing: Acid transfer lines, corrosive media backflow prevention.

Sour Gas Service (H₂S): Wellhead flowline check valves, pipeline check valves (NACE MR0175 compliant).

Marine Engineering: Shipboard seawater systems, ballast pump discharge (classification society certified).

Water Treatment: Pump discharge lines, filtration system isolation.

Power Generation: Cooling water pump check valves, auxiliary systems.

Critical Note: Swing check valves require sufficient forward flow velocity to fully open the disc. Minimum recommended velocities: 10 ft/s (3 m/s) for horizontal lines, 5 ft/s (1.5 m/s) for vertical-up lines. For low flow conditions, consider spring-assisted or nozzle check valves. Do not use swing check valves in vertical-down flow.

1. What is the difference between swing check and dual plate check valves?
Swing check valves have a single disc that swings on a hinge pin – provides lower pressure drop but requires more space. Dual plate check valves have two spring-loaded plates that open with flow – more compact, quicker closing, but slightly higher pressure drop. For seawater applications, swing check is preferred for large diameter lines.

2. Can swing check valves be installed vertically?
Yes, but only in vertical-up flow (flow upward). Vertical-down installation will cause the disc to close due to gravity. For vertical-down flow, use lift check or spring-assisted check valves.

3. Why choose Duplex 2205 over 316L for swing check valves in seawater?
Duplex 2205 offers twice the yield strength and superior chloride SCC resistance. In seawater, 316L is susceptible to crevice corrosion and pitting. Duplex 2205 provides reliable long-term service.

4. Are these check valves suitable for sour service (H₂S)?
Yes, Duplex 2205 swing check valves are fully NACE MR0175 / ISO 15156 compliant for sour service up to 232°C (450°F). HIC and SSC test reports available upon request.

5. What is the minimum flow velocity for proper disc opening?
Minimum recommended velocity is 10 ft/s (3 m/s) for horizontal lines. Below this, disc may not open fully, causing flutter and premature wear.

Complete Product Range: Flanged, wafer, lug, tilting disc, dual plate, pressure seal – all types available.

Strict Quality Control: API 6D, API 594, ISO 9001, PED certified.

NACE MR0175 / ISO 15156 Compliant: Full documentation for sour service applications.

NORSOK M-650 Qualified: For offshore and subsea projects.

Ferrite Controlled: 35–65% ferrite documented on every valve.

100% Pressure Tested: Hydrostatic shell and seat tests.

Full Traceability: Heat number on body – traceable to raw material.

Marine & Offshore Certified: ABS, BV, DNV, LR, GL certifications available.

Global Delivery: Exported to major offshore and desalination projects worldwide.

Tel / WhatsApp:
Victor: +86 15575100681
Jack: +86 18390957568

E-mail: info@womicstainless.com

Website: www.womicsteel.com

Contact Womic Steel today for a competitive quote on Duplex 2205 stainless steel swing check valves. We offer certified quality, NACE MR0175 compliance, ferrite-controlled material, fast production lead times, and reliable global delivery for your offshore and seawater projects.

Stock Examples (Flanged Duplex 2205 Swing Check Valves – Class 150 – Bolted Bonnet – Single Disc):

Stock Examples (Wafer Duplex 2205 Dual Plate Check Valves – Class 150 – Compact Design):

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