Nickel Aluminum Bronze (NAB) Valves: The Complete Guide to Seawater Service Applications
March 11, 2026 | 10 min read
When it comes to handling seawater, brackish water, and corrosive marine environments, few materials can match the performance of Nickel Aluminum Bronze (NAB), also known as NiAlBr or Nickel-Aluminum Bronze. This comprehensive guide explores everything you need to know about NAB valves, from material properties to application-specific recommendations.
What is Nickel Aluminum Bronze (NAB)?
Nickel Aluminum Bronze is a copper-based alloy containing aluminum (9-12%), nickel (3-6%), and iron (3-5%). This unique composition gives NAB exceptional corrosion resistance, particularly in seawater and marine environments. The material is designated as ASTM B148 C95800 and is widely recognized as one of the best materials for seawater service valves.
Chemical Composition (ASTM B148 C95800)
| Element | Content (%) | Purpose |
|---|---|---|
| Copper (Cu) | 78-82% | Base metal |
| Aluminum (Al) | 9-12% | Corrosion resistance, strength |
| Nickel (Ni) | 3-6% | Corrosion resistance |
| Iron (Fe) | 3-5% | Strength, wear resistance |
| Manganese (Mn) | 0.5-2% | Deoxidizer |
Key Properties of NAB
Corrosion Resistance
Excellent resistance to seawater corrosion, stress corrosion cracking, and pitting. Superior to stainless steel in many marine applications.
High Strength
High tensile strength (typically 450-600 MPa) with excellent fatigue resistance, suitable for demanding applications.
Fire Safety
NAB has excellent fire safety characteristics and meets API 607 fire-safe requirements for critical applications.
Biofouling Resistance
Natural resistance to marine biofouling, reducing maintenance requirements in seawater applications.
Applications of NAB Valves
Nickel Aluminum Bronze valves are specifically designed for demanding seawater applications across multiple industries:
Marine & Shipbuilding
- Ship hull piping systems
- Seawater cooling systems
- Ballast water systems
- Marine fire protection
Offshore Oil & Gas
- Platform seawater systems
- Process piping
- Injection water systems
- Subsea applications
Desalination Plants
- Intake systems
- Brine discharge
- Process water lines
- Cooling water systems
Fire Protection
- Marine fire systems
- Platform fire protection
- Emergency seawater supply
- Sprinkler systems
Types of NAB Valves Available
Supreme Valves manufactures a comprehensive range of NAB valves for various applications:
| Valve Type | Standard | Pressure Class | End Connection | Applications |
|---|---|---|---|---|
| NAB Ball Valve | BS 5351, API 6D | Class 150-600 | Screwed, Flanged | On-off, seawater service |
| NAB Gate Valve | API 600 | Class 150-600 | Flanged, Butt Weld | Isolation, full flow |
| NAB Globe Valve | API 623 | Class 150-600 | Flanged, Butt Weld | Throttling, regulation |
| NAB Check Valve | API 594 | Class 150-600 | Flanged, Wafer | Backflow prevention |
| NAB Butterfly Valve | API 609 | Class 150-300 | Wafer, Lug, Flanged | Large diameter, throttling |
NAB vs Other Materials
Understanding how NAB compares to other commonly used valve materials is crucial for proper material selection:
| Property | NAB (C95800) | SS316 | Bronze | Brass |
|---|---|---|---|---|
| Seawater Corrosion | Excellent | Good (risk of pitting) | Good | Fair |
| Strength | High | High | Medium | Medium |
| Biofouling Resistance | Excellent | Poor | Good | Fair |
| Fire Safety | Excellent | Good | Good | Poor |
| Cost | Medium-High | Medium | Medium | Low |
Why Choose NAB?
- Superior lifespan in seawater (2-3x longer than SS316 in many cases)
- Lower maintenance costs due to biofouling resistance
- Fire-safe certification for critical applications
- Excellent for offshore and marine environments
- Proven track record in oil & gas, desalination, and marine industries
Standards & Certifications
NAB valves from Supreme Valves comply with international standards:
Material Specification
Ball Valve Design
Fire Safe Testing
Testing & Inspection
Pipeline Valves
Need NAB Valves for Your Project?
Supreme Valves is a leading manufacturer and exporter of Nickel Aluminum Bronze valves for seawater applications.