UNS C69400 Copper Alloy Chemical Composition Properties, Grade, Charts and Document

UNS C69400 is a famous high-grade copper alloy that stands out with its outstanding mechanical properties and corrosion resistance. Mainly copper but also manganese, iron, aluminum and nickel upon which you finely tune these other elements to enhance the overall strength and durability of an alloy. C69400 paint gives its excellent thermal conductivity, electrical conductivity, and machinability property causing it to be widely used in naval and ship engineering, electrical engineering, as well as aerospace applications. Moreover, its remarkable ability to resist corrosion, erosion, and fouling by marine organisms (bioufouling) is another factor that makes it the first choice material for hard environments. Detailed sites with charts and documents providing the chemical composition, mechanical properties and grading specifications of the material for the engineers and manufactures to look for reliable materials when making decision for demanding applications.

UNS C69400 Copper Alloy Chemical Composition And Grade Table

UNS C69400 which is copper-nickel-silicon alloy has this corrosion resistance which is out of the ordinary especially in this marine environment. This alloy is composed of about 60% copper, 25% nickel, and 1.5% silicon which contribute to its strength, good thermal conductivity and high resistance to attrition and cavitation the best in the world. It is widely applied in such field as marine engineering, where fortification against biofouling and durability are of high importance. UNS C69400 is frequently used in sea water piping systems, heat exchangers, and in marine systems in particular. Its chemical composition and grade graph show that it is designed to cope with harsh conditions, which are often featured by corrosion speed and strength requirement.

UNS C69400 Copper Alloy Composition Table
Elements Cu Pb Zn Fe Si
Min (%) 80.0 - - - 3.5
Max (%) 83.0 0.30 Rem 0.20 4.5

The Advantages and Disadvantages of UNS C69400 Copper Material Properties, C69400 Properties


  • High corrosion resistance: UNS C69400 copper alloy, also called silicon brass, has the ability to resist corrosion in different environments, including seawater, therefore it is suitable for marine applications like shipbuilding and offshore structures.

  • High strength: It has good tensile and yield strength, which makes it suitable for structural applications where strength is necessary.

  • Good machinability: UNS C69400 is simple to machine and, therefore, the production processes are easy to carry out and the manufacturing of complex parts is cost-effective.

  • Biostatic properties: Copper alloys like UNS C69400 have the antimicrobial properties that inhibit the growth of bacteria and fungi on their surface, thus, they are the most suitable for the medical and food processing equipment.

  • Good thermal conductivity: The alloy has good thermal conductivity, which makes it perfect for heat transfer applications such as heat exchangers and HVAC systems.


  • Cost: UNS C69400 copper alloy can be more expensive than other copper alloys or other materials, which may result in its high cost for certain applications.

  • Limited availability: The UNS C69400 may be unavailable depending on the region or supplier, which may result in longer lead times or higher procurement costs.

  • Silicon content: The silicon in UNS C69400 may make the weldability and solderability of the material affected, thus, special techniques and procedures for joining it should be used.

  • Potential for dezincification: As with many brass alloys, UNS C69400 is prone to dezincification in some environments, which can result in the loss of its mechanical properties and structural integrity.

  • Surface tarnishing: Although it has good corrosion resistance, UNS C69400 may tarnish over time, especially in outdoor environments with exposure to pollutants, therefore, periodic maintenance is required to keep its appearance.

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Frequently Asked Questions

What is the chemical composition of the UNS C69400 copper alloy?

The chemical composition usually consists of about 58-62% of copper (Cu), 1. 5-2. 5% iron (Fe), 0% 5-1. 5% of aluminum (Al), 0. 35% max manganese (Mn), and slight amounts of other elements like lead (Pb) and nickel (Ni).

What are the mechanical properties of UNS C69400 copper alloy?

UNS C69400 has high tensile strength, good yield strength, moderate ductility, and excellent corrosion resistance, specially in marine environments.

Is there a particular grade for UNS C69400 copper alloy?

Indeed, it is widely linked to the standards ASTM B171/B171M for naval brass plate, sheet, strip, and rolled bar and ASTM B21/B21M for naval brass rod, bar, and shapes.

Where can I get charts on the properties of UNS C69400 copper alloy?

Comprehensive charts that show the mechanical and physical properties of UNS C69400 are available in standards like ASTM B171/B171M, which give the data on tensile strength, yield strength, elongation, hardness, etc.