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Tungum (UNS C69100) is a high‑strength copper alloy widely used in safety‑critical hydraulic and instrumentation tubing. It has been specified across defence, offshore energy, and industrial applications for decades due to its unique combination of mechanical strength, fatigue resistance, and corrosion performance. The following compares the mechanical and physical properties of Tungum with two commonly used copper‑nickel alloys: 90/10 CuNi (UNS C70600) and 70/30 CuNi (UNS C71500). This comparison highlights the differences in strength, physical characteristics, and typical engineering applications.
Tungum is a copper‑zinc‑aluminium‑nickel‑silicon alloy originally developed for high‑pressure hydraulic systems. The alloy combines excellent corrosion resistance with significantly higher strength than traditional copper‑based tubing materials.
Copper‑nickel alloys such as 90/10 and 70/30 CuNi are widely used in marine applications due to their outstanding resistance to seawater corrosion and biofouling. These alloys are commonly used in ship piping, heat exchangers, and offshore systems.
Property
Tungum (C69100)
CuNi 90/10 (C70600)
CuNi 70/30 (C71500)
Ultimate Tensile Strength
≈480 MPa
≈300 MPa
≈350 MPa
Yield Strength (0.2%)
≈240 MPa
≈100 MPa
≈120 MPa
Elongation
≈45%
30–40%
25–35%
Hardness
≈140 HV
80–120 HV
100–150 HV
The most significant difference between Tungum and copper‑nickel alloys is mechanical strength. Tungum provides approximately double the yield strength of 90/10 CuNi, enabling it to withstand higher operating pressures in hydraulic and instrumentation systems. This higher strength also contributes to improved fatigue resistance in dynamic service conditions.
Density
8.52 g/cm³
8.9 g/cm³
8.95 g/cm³
Elastic Modulus
≈117 GPa
≈135 GPa
≈150 GPa
Thermal Conductivity
≈100 W/m·K
≈50 W/m·K
≈29 W/m·K
Coefficient of Expansion
≈19 ×10⁻⁶ /°C
≈17 ×10⁻⁶ /°C
≈16 ×10⁻⁶ /°C
Tungum also exhibits significantly higher thermal conductivity than copper‑nickel alloys, which can be beneficial in applications where heat transfer or temperature stability is important. Copper‑nickel alloys have a slightly higher modulus of elasticity, making them somewhat stiffer, but this does not compensate for their lower strength in high‑pressure tubing systems.
All three alloys demonstrate strong resistance to corrosion in marine and offshore environments. Copper‑nickel alloys are particularly well known for their resistance to seawater corrosion and biofouling, making them common choices for shipboard piping systems and heat exchangers.
Tungum also provides excellent resistance to corrosion and stress corrosion cracking in aggressive environments. Its performance has been proven in numerous defence hydraulic systems, naval military vessels, offshore oil and gas platforms, and subsea control systems where reliability is critical.
• Hydraulic tubing for defence and naval systems
• High‑pressure instrumentation tubing
• Offshore hydraulic control systems
• Brake and control lines
• Seawater piping
• Marine heat exchangers and condensers
• Shipboard piping systems
• Desalination plants
When selecting tubing materials for demanding applications, engineers must balance mechanical strength, corrosion resistance, and long‑term reliability, and weight. While copper‑nickel alloys remain excellent materials for seawater service, Tungum offers a unique combination of high strength and corrosion resistance that makes it particularly well suited for hydraulic and control systems where pressure capability and fatigue resistance are critical.
As a result, Tungum continues to be specified across defence platforms, offshore energy projects, and high‑integrity hydraulic systems worldwide.
