C46700 Naval Brass Vs C46400: What’s The Difference?

When selecting marine-grade copper alloys, C46700 Naval Brass and C46400 Naval Brass are two commonly compared materials. While both are designed for seawater environments, their chemical composition, corrosion behavior, and application focus differ significantly.

This guide provides a professional, engineering-level comparison to help buyers, engineers, and distributors choose the right alloy for marine, offshore, and industrial use.

C46400 is the most widely used traditional naval brass, classified as a copper–zinc–tin alloy (CuZnSn).

Key Characteristics:

~60% Copper, ~39% Zinc, ~1% Tin

Duplex (α + β) structure → high strength

Excellent resistance to:

Seawater corrosion

Dezincification

Stress corrosion cracking

Why Tin Matters:

The ~1% tin addition is critical-it significantly improves resistance to saltwater corrosion and prevents zinc loss.

👉 In short:
C46400 = Classic marine brass (cost-effective, reliable, widely standardized)

C46700 is a more advanced marine brass, typically categorized as a copper–zinc–aluminum alloy (CuZnAl).

Key Characteristics:

Contains aluminum instead of tin

Often designated as:

CuZn23Al3

Admiralty / Aluminum naval brass

Designed for:

Higher strength

Enhanced erosion resistance

Severe seawater conditions

Key Advantages of Aluminum Addition:

Better erosion-corrosion resistance

Improved strength at high flow rates

Enhanced performance in:

Desalination plants

Heat exchangers

Pump systems

👉 In short:
C46700 = Upgraded naval brass (higher performance, more aggressive environments)

Key Insight:

C46400 → Tin-based corrosion protection

C46700 → Aluminum-based corrosion + erosion resistance

👉 Conclusion:
C46700 is stronger and more wear-resistant, but C46400 is easier to machine and fabricate.

Key Difference:

C46400 excels in general marine conditions

C46700 performs better in high-velocity / aggressive seawater systems

C46400 Typical Uses:

Marine fasteners

Valve stems & pump parts

Heat exchanger plates

Ship hardware

C46700 Typical Uses:

Condenser tubes

Desalination systems

Pump shafts & impellers

Offshore heat exchangers

Choose C46400 if:

You need cost-effective marine brass

Applications include:

Fasteners

Valves

General seawater exposure

You require good machinability

Choose C46700 if:

You are dealing with:

High flow seawater

Erosion / cavitation conditions

Applications include:

Heat exchangers

Condensers

Desalination systems

You need longer service life under harsh conditions

In real-world marine engineering:

C46400 remains the industry standard naval brass due to its balance of cost, availability, and corrosion resistance.

C46700, however, is increasingly preferred in modern offshore and desalination projects, where erosion-corrosion is the dominant failure mode rather than simple corrosion.

👉 This shift reflects a broader material trend:
From tin-based brasses → aluminum-enhanced high-performance alloys

1. What is the main difference between C46700 and C46400?

The core difference lies in alloying elements:

C46400 is a tin-containing naval brass (Cu-Zn-Sn)

C46700 is an aluminum-containing naval brass (Cu-Zn-Al)

👉 This leads to better erosion resistance and higher strength in C46700, while C46400 offers better machinability and lower cost.

2. Which alloy has better corrosion resistance in seawater?

Both alloys perform well in seawater, but:

C46400 → excellent for general marine environments

C46700 → superior in high-velocity or turbulent seawater systems

👉 If erosion-corrosion is a concern, C46700 is the better choice.

3. Is C46700 stronger than C46400?

Yes.
C46700 generally has higher strength and hardness due to aluminum addition, making it more suitable for:

Pump shafts

Condensers

High-load marine components

4. Which alloy is easier to machine?

C46400 is easier to machine.

C46400 → better machinability, easier for mass production

C46700 → harder, more wear on tools

👉 For CNC machining and fastener production, C46400 is preferred.

5. Which material is more cost-effective?

C46400 is more cost-effective due to:

Wider availability

Easier processing

Lower alloying cost

👉 C46700 is more expensive, but offers longer service life in harsh environments.

6. Can C46700 replace C46400?

Yes, in many cases-but not always necessary.

Replace with C46700 when:

High flow rate seawater

Erosion or cavitation risk

Keep C46400 when:

Standard marine hardware

Budget-sensitive projects

7. Which alloy is better for heat exchangers?

C46700 → better for high-performance heat exchangers and condensers

C46400 → suitable for general-purpose heat exchange systems

8. What industries use C46400 vs C46700?

C46400 Applications:

Marine hardware

Valves & fasteners

Shipbuilding components

C46700 Applications:

Desalination plants

Offshore platforms

Power plant condensers

9. Does aluminum make C46700 better than tin-based brass?

Not universally-but in high-flow and erosion-prone systems, yes.

Tin (C46400) → protects against dezincification

Aluminum (C46700) → improves erosion + mechanical strength

👉 Different mechanisms, different advantages.

10. Which alloy should I choose?

Quick selection guide:

Choose C46400 👉 cost-effective, standard marine use

Choose C46700 👉 high-performance, aggressive seawater systems