Engineering guides: API 600 gate valve guide
Seawater Service

NAB Gate Valve – API 600 for Seawater

Nickel Aluminium Bronze (NAB) gate valves manufactured to API 600 standard for continuous seawater service. Body material ASTM B148 C95800. Pressure Class 150. Sizes from 1/2" to 12". Ideal for desalination plants, offshore platforms, marine vessels, and seawater cooling systems.

Quick Summary

NAB Gate Valve = Gate valve made from Nickel Aluminium Bronze (ASTM B148 C95800). Used for seawater because NAB resists corrosion, erosion, and biofouling. API 600 design standard. Class 150 pressure rating. Available 1/2" to 12". Typical applications: desalination, offshore oil & gas, marine, power plant seawater cooling.

NAB Gate Valve API 600 Nickel Aluminium Bronze C95800 Seawater
In Stock Seawater Rated API 600

Key Specifications

Design Standard: API 600
Pressure Class: 150 (PN20)
Body Material: ASTM B148 C95800
Size Range: 1/2" to 12"
End Connection: Flanged (ASME B16.5)
Testing: API 598
Service: Continuous Seawater
Delivery: 6-8 Weeks
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Export Ready: Supplied to Hyundai Engineering, SWCC, DEWA, Petrofac, and major EPC contractors. EN 10204 3.1 MTCs. Third-party inspection supported.

What is NAB (Nickel Aluminium Bronze)?

Nickel Aluminium Bronze (NAB), designated as ASTM B148 C95800, is a copper-based alloy specifically engineered for seawater applications. It contains approximately:

  • Copper: 79% minimum (base metal)
  • Aluminium: 8.5-9.5% (corrosion resistance)
  • Nickel: 4-5% (strength & toughness)
  • Iron: 3.5-4.5% (erosion resistance)
  • Manganese: 0.8-1.5% (castability)

Why NAB for Seawater?

  • Corrosion Resistant: Excellent resistance to seawater, brackish water, and chlorides
  • Anti-Biofouling: Natural resistance to marine organism attachment
  • Erosion Resistant: Withstands high-velocity seawater flow
  • Self-Healing: Protective oxide layer reforms if damaged
  • High Strength: 585 MPa tensile, 240 MPa yield

Materials of Construction (MOC)

Component Material Specification
Body & Bonnet Nickel Aluminum Bronze (ASTM B148 C95800)
Stem / Spindle Monel 400 / K500
Seat / Trim NAB / PTFE / Viton

Technical Specifications

Parameter Specification / Standard
Manufacturing / Design Standard API 609 / API 600 / ASME B16.34
Testing Standard API 598 / EN 12266-1
Pressure Rating Class 150 / Class 300 / PN16

Frequently Asked Questions

What is a NAB gate valve?

A NAB gate valve is a gate valve with body and trim made from Nickel Aluminium Bronze (NAB), specifically ASTM B148 C95800. NAB provides exceptional resistance to seawater corrosion, erosion, and biofouling, making it the preferred material for marine and desalination applications. NAB gate valves are typically manufactured to API 600 standard.

Why use NAB gate valves for seawater?

NAB (Nickel Aluminium Bronze) gate valves are ideal for seawater because: (1) Excellent resistance to seawater corrosion and pitting, (2) Natural anti-biofouling properties that resist marine growth, (3) High strength and durability in marine environments, (4) Superior erosion resistance compared to stainless steel in flowing seawater, (5) Self-healing oxide layer that reforms if damaged. ASTM B148 C95800 is the standard specification for NAB castings.

What is ASTM B148 C95800?

ASTM B148 C95800 is the specification for Nickel Aluminium Bronze (NAB) castings. The chemical composition is approximately: Copper 79% min, Aluminium 8.5-9.5%, Nickel 4-5%, Iron 3.5-4.5%, Manganese 0.8-1.5%. It has minimum tensile strength of 585 MPa (85 ksi) and yield strength of 240 MPa (35 ksi). C95800 is widely used for seawater valves, pumps, and marine hardware.

What is API 600 gate valve?

API 600 is the American Petroleum Institute standard for steel gate valves with flanged, butt-welding, and lens ring ends. It covers design, materials, dimensions, testing, and marking requirements for gate valves in refinery and pipeline service. API 600 gate valves are typically bolted bonnet design with rising stem and are available in pressure classes 150, 300, 600, 900, 1500, and 2500.

What sizes are NAB gate valves available in?

NAB gate valves per API 600 are available in sizes from 1/2 inch (DN15) to 12 inch (DN300). Common sizes for seawater service include 1/2", 1", 1-1/2", 2", 3", 4", 6", and 8". Larger sizes up to 24 inch can be manufactured on request. Pressure rating is typically Class 150 (PN20) for seawater applications.