Flanges for Marine & Offshore Applications
Corrosion-resistant stainless, duplex, and nickel alloy flanges engineered for shipboard and offshore platform duty with full classification society compliance.
Engineered for Extreme Seawater Environments
Marine environments demand exceptional corrosion resistance and reliability. ApiFlange specializes in stainless steel, duplex, and exotic nickel alloy flanges designed for shipboard piping, offshore drilling platforms, subsea equipment, and coastal industrial facilities. With expertise in classification society requirements (DNV, ABS, BV, Lloyd's), cathodic protection systems, and seawater chemistry, we deliver flanges that withstand the harshest marine environments with uncompromising reliability.
Seawater Proven
Stainless & duplex
Offshore Ready
DNV certified
Cathodic Protection
Compatible design
Zero Tolerance
No crevice corrosion
Materials for Seawater Service
Seawater is one of the most corrosive environments. Material selection is critical to ensure 20-30 year service life in marine applications. ApiFlange stocks comprehensive options from standard stainless to premium duplex and exotic alloys.
Stainless Steel Options
304/304L
Max: to 400°F | Auxiliary water, low-temp
316/316L
Max: to 400°F | General seawater duty
Duplex 2205
Max: to 250°F | High-strength seawater
Super Duplex 2507
Max: to 250°F | Extreme corrosion
Nickel Alloys
Monel 400/K-500
Seawater and fluorine
Inconel 625
Severe saltwater environments
Hastelloy C-276
Extreme chemical attack
Titanium Gr. 2/5
Subsea and deepwater
Marine Applications
Shipboard Systems
- •Seawater cooling loops
- •Fire main systems
- •Ballast systems
- •Sanitary water
- •Bilge systems
Offshore Platforms
- •Production risers
- •Power generation
- •Process water
- •Utility systems
- •Subsea manifolds
Subsea Equipment
- •Trees and jumpers
- •Control systems
- •Product pipelines
- •Jumper connections
- •Mud lines
Classification Society Compliance
Marine vessels and offshore structures must comply with classification society rules. ApiFlange's marine flanges meet or exceed the requirements of all major classification societies.
Approved Classification Societies
- ✓DNV GL (Det Norske Veritas)
- ✓ABS (American Bureau of Shipping)
- ✓Bureau Veritas (BV)
- ✓Lloyd's Register (LR)
- ✓RINA (Registro Italiano Navale)
- ✓ClassNK (Japan)
Material Standards
- ✓ASME B16.5 / B16.47
- ✓ASTM A182 (Stainless)
- ✓ASTM B564 (Nickel Alloy)
- ✓EN standards equivalent
- ✓DNV materials approval
- ✓Lloyd's certification
Corrosion Management & Design Considerations
Seawater corrosion requires comprehensive system design. Beyond flange material selection, ApiFlange provides guidance on cathodic protection compatibility and crevice corrosion prevention.
Design Best Practices
- •Select material compatible with cathodic protection
- •Avoid galvanic couples between different metals
- •Minimize crevices in flange design
- •Ensure proper gasket sealing
- •Account for biofouling in design
Testing & Verification
- •ASTM G48 seawater corrosion testing
- •Pitting resistance equivalent number (PREN)
- •Crevice corrosion resistance analysis
- •Galvanic corrosion testing
- •Long-term exposure verification
Sizes & Pressure Classes
ApiFlange supplies marine flanges in all standard ASME sizes and pressure classes, from instrument connections to large bore subsea jumpers.
Standard & Custom Sizes
½" to 60"+
Pressure classes 150 through 2500 psi
Building Your Marine System?
Our marine specialists can help you select the right material grade and classification society certifications for your seawater application.