C78200 Copper Alloy Bar

C78200 belongs to copper nickel zinc alloy (commonly known as nickel silver), whose core components are copper (Cu), nickel (Ni), and zinc (Zn), and contains a small amount of other trace elements to optimize performance. The typical composition range is: copper content 60% 65%, nickel content 10% 15%, zinc content 20% 25%. The addition of nickel significantly improves the corrosion resistance and strength of the alloy, while the blending of zinc improves the formability and cost-effectiveness. The synergistic effect of trace elements further enhances the fatigue resistance and stability of the material.

C78200 is a high-performance white copper alloy widely used in precision instruments, ship components, and the electronics industry due to its excellent mechanical properties, corrosion resistance, and processing characteristics.

• Standards and Specifications

ASTM B98: Standard specification for copper-silicon alloy bars.

UNS C78200: Unified Numbering System designation for this alloy.

• Composition

Copper (Cu): ~90-94% (provides excellent electrical and thermal conductivity).

Nickel (Ni): ~4-6% (enhances strength and corrosion resistance).

Silicon (Si): ~1-2% (improves hardness and wear resistance).

• Melting and casting: using vacuum melting technology to accurately control the copper nickel zinc ratio and reduce impurities.
• Hot processing: Optimizing grain structure through hot rolling or extrusion molding.
• Cold processing: Cold rolling or drawing to achieve high-precision dimensions and surface smoothness.
• Heat treatment: Annealing process adjusts the soft and hard state of materials to meet different needs.
• Surface treatment: can be polished, plated or passivated to enhance corrosion resistance and aesthetics.

• Strong corrosion resistance: resistant to pitting and stress corrosion cracking in seawater and humid environments.
• Easy to process and shape: suitable for complex processes such as stamping, cutting, and welding.
• Conductive and Thermal Balance: Suitable for precision components that require heat dissipation and conductivity.
• Good wear resistance: The high hardness state can withstand long-term friction loss.
• Decorative highlight: Silver white luster often replaces pure silver for high-end products

1. Excellent corrosion resistance
C78200 exhibits excellent corrosion resistance in seawater, humid environments, and weakly acidic and alkaline media. The passivation effect of nickel effectively prevents oxidation and pitting corrosion, making it suitable for components exposed to harsh working conditions for a long time.
2. Mechanical performance balance
This alloy has high tensile strength (up to 500 MPa or more) and good ductility. After cold working, it can further improve hardness while maintaining moderate toughness, making it suitable for precision parts that require complex forming.
3. Electrical and Thermal Properties
As a copper based alloy, C78200 has excellent electrical and thermal conductivity. Although slightly lower than pure copper, it is superior to most copper alloys and can meet the high electrical and thermal performance requirements of electronic connectors, heat dissipation components, and other scenarios.
4. Adaptability to Processing and Surface Treatment
The material is easy to punch, cut, and weld, and has a high surface finish after polishing. It can be further improved in appearance and wear resistance through coating or oxidation treatment.

• Electronics industry: connectors, relay springs, micro motor brushes.
• Precision manufacturing: instrument gears, medical device accessories.
• Ship engineering: seawater valves, pump body seals.
• Decoration field: tableware, jewelry, building hardware.
• New energy: battery contact plates, conductive components of photovoltaic equipment.

When sourcing C78200 copper alloy bars, consider confirming the following with your supplier:

• Temper/Hardness condition – OS (annealed) through H06 (extra hard) available
• Dimensions – Diameter, length, straightness tolerance
• Form – Round, hex, square, or custom profile
• Surface finish – As-drawn, polished, or machined
• Certification – Material test reports, composition analysis
• Quantity – Minimum order quantity and lead time

Q1: What are the main components of C78200 Copper Alloy?
A: C78200 white copper belongs to nickel copper alloy, with copper (Cu) as the matrix and nickel (Ni) as the main alloying element, while containing small amounts of manganese (Mn), iron (Fe) and other elements. In its typical chemical composition, the nickel content is about 19% -21%, the copper content accounts for the remainder, and the manganese and iron content is usually less than 1%.

Q2: Does the electrical conductivity of C78200 Copper Alloy decrease due to processing?
A: Through the precise temperature-controlled thermal treatment process, C78200 Copper Alloy can recover more than 95% conductivity after cold processing to ensure stable performance.

Q3: What surface treatments is C78200 Copper Alloy suitable for?
A: Support silver plating, nickel plating, passivation and other processing, it is recommended to degreasing and pickling before pretreatment to improve adhesion.

Q4: How to distinguish copper C78200 Copper Alloy from copper chromium zirconium?
A: C78200 Copper Alloy has better cutting ability and lower cost, while chromium zirconium copper (CuCrZr) focuses on high-strength wear resistance scenarios.

Q5: What is the corrosion resistance of C78200 Copper Alloy ?
A: Corrosion resistance in conventional industrial environment is better than pure copper, but strong acid and alkali environment is recommended to use with surface coating.

Q6: What parameters are required when ordering copper C78200 Copper Alloy ?
A: It is necessary to specify the alloy grade (such as C78200), state (hard/semi-hard), dimensional tolerance and testing standard (ASTM/GB).

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