C76400 Copper

Grade Designation & Standards

Standard Grade: C76400 (Cu-Ni-Zn Alloy, Nickel Silver/German Silver)

International Equivalents:

• UNS: C76400 (ASTM B151/B206)

• EN: CW409J (DIN 17663), CuNi18Zn20

• JIS: C7521

Applicable Standards:

• ASTM B151M, B206M

• EN 12163 (Europe)

• GB/T 5231-2012 (China)

Product Features

1. High Strength & Wear Resistance: Tensile strength up to 640-730 MPa (hard state), suitable for high-load applications.

2. Superior Corrosion Resistance: Resists seawater, weak acids, and high-temperature oxidation (corrosion rate ≤0.003 mm/a), anti-biofouling.

3. Excellent Machinability: Supports cold/hot working, welding (TIG/laser), and stamping; surface finish up to Ra 0.1μm.

4. Aesthetic & Functional: Silver-white appearance for decorative and industrial use.

Common Product Forms & Dimensions 

Product Form	Size Range	Delivery Condition
Sheet	Thickness: 0.05-1.5mm, Width ≤500mm	Soft (M), Hard (H)
Rod	Diameter: 3-120mm, Length: 2-6m	Drawn, Hot-Rolled
Tube	OD: 2-150mm, Wall Thickness: 0.3-15mm	Cold-Drawn, Half-Hard
Wire	Diameter: 0.05-6.0mm	Coiled or Straight
Strip	Thickness: 0.1-3.0mm	Custom Cut

Chemical Composition

Element	Content (%)	Function/Limit
Cu+Ag	58.5-61.5	Base material, corrosion resistance & conductivity
Ni+Co	16.5-19.5	Enhances corrosion resistance & strength
Zn	Balance	Adjusts plasticity, reduces cost
Fe	≤0.25	Trace impurities
Pb	≤0.05	Strictly controlled
Mn	≤0.50	Improves machinability

Physical Properties

Property	Value	Remarks
Density	8.72 g/cm³	High density for precision parts
Electrical Conductivity	5.7-6% IACS	Moderate conductivity for industrial use
Thermal Conductivity	19-33 W/(m·K)	Moderate heat dissipation
Thermal Expansion	17.2×10⁻⁶/°C (20-300°C)	Excellent thermal stability
Elastic Modulus	125 GPa	Material rigidity indicator

Mechanical Properties 

Property	Soft (M)	Hard (H)
Tensile Strength (σb)	380-450 MPa	640-730 MPa
Yield Strength (σ0.2)	105-250 MPa	≥600 MPa
Elongation (δ10)	20-40%	3-9%
Vickers Hardness (HV)	80-130	200-230
(Values vary slightly depending on product form and state. Data sources: )

Core Advantages

1. Industry-Leading Corrosion Resistance: Resists stress corrosion cracking and high-temperature oxidation for marine/chemical environments.

2. Balanced Performance: Combines strength, wear resistance, and machinability for complex applications.

3. Cost-Efficiency: Lower cost than high-nickel alloys (e.g., C71500) with comparable performance.

Product Applications

1. Marine Engineering: Ship propellers, seawater valves, offshore platform components.

2. Chemical Equipment: Corrosion-resistant pipes, pump bodies, reactor linings.

3. Mechanical Engineering: Gears, bearings, high-load connectors.

4. Electronics & Decoration: Precision instrument housings, eyewear frames, decorative items.

Processing Guidelines

1. Welding: Prefer TIG or laser welding; interpass temperature ≤100°C to avoid zinc evaporation.

2. Annealing: Post-cold working, anneal at 650-750°C to relieve stress.

3. Machining: Cutting speed ≤50 m/min; use carbide tools with oil-based coolant.

Key Application Scenarios

• High-Temperature & High-Pressure Systems: Petrochemical valves, nuclear reactor seals.

• Precision Machinery: Aerospace components, medical device wear parts.

FAQs

1. Q: How does C76400 differ from brass?

A: C76400 offers superior corrosion resistance and strength but at a higher cost.

2. Q: Is it suitable for strong acid environments?

A: Suitable for weak acids and seawater but avoid strong oxidizing acids (e.g., nitric acid).

3. Q: Post-weld heat treatment required?

A: Recommend low-temperature annealing (250-300°C) to eliminate residual stress.

Standard References

• Chemical Composition: ASTM B151M, GB/T 5231-2012.

• Mechanical Testing: ASTM B206M, EN 12163.

• Processing: ISO 426-2, Aerospace Standard AMS 4590.

Note: Data consolidated from industrial standards and technical documents. Actual parameters may vary slightly due to manufacturing processes. Refer to supplier test reports for precise specifications.