corrosive
Valves for Seawater Service
Seawater is highly corrosive due to dissolved chlorides (~3.5% NaCl), dissolved oxygen, biological activity (MIC), and temperature. Carbon steel corrodes rapidly; copper alloys, duplex stainless, and super-duplex are preferred for seawater service.
Pressure Range
0.5–25 bar - seawater lift to process system
Temperature
0–40°C (ambient seawater); up to 120°C in desalination brine
Industries
Offshore oil & gas, Desalination, Aquaculture
What valves are used for Seawater service?
Super-duplex butterfly valve are recommended for Seawater service: PREN >40, handles high chloride seawater - offshore standard.
Key Properties - Seawater
- ~35,000 ppm chloride - aggressive to austenitic SS
- Oxygen content drives corrosion at ambient temperature
- Microbiologically influenced corrosion (MIC) from sulfate-reducing bacteria
- Biofouling blocks valve internals over time
- Velocity-accelerated corrosion in copper alloys above 3 m/s
Vajra Industrial Solutions manufactures and supplies valves for Seawater service — including super-duplex butterfly valve — in corrosion-appropriate materials selected for the operating conditions described here, with full material and test documentation.
Need valves for Seawater service?
Send your fluid conditions — we'll recommend the right valve, material and standard, with a 24-hour quote.
Material Compatibility - Seawater
Ratings are indicative. Actual compatibility depends on concentration, temperature, velocity, and presence of contaminants. Always consult corrosion tables or a materials engineer.
| Material | Rating | Notes |
|---|---|---|
| Carbon Steel | Poor | High corrosion rate. Acceptable only with cathodic protection and coating. |
| SS 316L | Fair | Pitting and crevice corrosion risk. Not recommended for seawater service. PREN must be verified. |
| Duplex 2205 | Good | PREN ~35 - acceptable for most seawater applications at ambient temperature. |
| Super-Duplex 2507 | Excellent | PREN ~43 - preferred for offshore seawater. Standard for North Sea applications. |
| Cupro-Nickel 90/10 | Good | Excellent for seawater up to 3 m/s velocity. Used in offshore fire water systems. |
| Naval Brass (HT Brass) | Good | Good for seawater at lower velocities. Not for high velocity or hot seawater. |
| Titanium Grade 2 | Excellent | Completely immune to seawater corrosion. Used in desalination. |
| Rubber-lined (EPDM) | Good | Good for seawater service at low pressure. |
Recommended Valves
Super-duplex butterfly valve
PREN >40, handles high chloride seawater - offshore standard
Full selection guideCupro-nickel ball valve
Excellent for fire water and cooling water seawater systems
Full selection guideTitanium ball valve
Zero corrosion - used in desalination and highly critical seawater
Full selection guideRubber-seated butterfly valve (EPDM)
Cost-effective for large diameter, low-pressure seawater service
Full selection guideValves to Avoid
Carbon steel without cathodic protection and coating
Standard 304 or 316 stainless steel valves
Valves with aluminium bronze trim in high-velocity seawater
Cast iron valves
Special Considerations
Applicable Standards
Shop Valves for Seawater Service
Other Fluid Services
Seawater Service — Procurement & Specification
Typical Applications
Available Standards
Material Options
Documentation Available
- -EN 10204 3.1 Material Test Certificates (heat traceable)
- -API 598 hydrostatic shell & seat test reports
- -Dimensional inspection reports
- -Full Manufacturing Data Record (MDR) / data book on request
Inspection Options
- -In-house QC inspection on every order
- -Third-party inspection (SGS / Bureau Veritas / TÜV / DNV) coordination
- -Witness and hold points accommodated on request
Order Quantities
Flexible — from single critical-spare valves to full project lots.
Export
Worldwide export with complete documentation (COO, EUR.1, packing lists) to 20+ countries.
Custom Engineering
Built to your specification — materials, trim, pressure class and special service (NACE, fire-safe, IBR, cryogenic).
Delivery Support
Dispatch from Vadodara, Gujarat with documented lead times and priority handling for urgent requirements.
Engineering references
Connected Engineering
Need Valves for Seawater Service?
Tell us your fluid, pressure, and temperature — we'll recommend the right valve, material, and standard, with a 24-hour quote.