Low thermal expansion CuNi Alloy CuNi34 for stable performance at high temperatures
CuNi34 is a copper-nickel alloy with approximately 34% nickel, known for its excellent resistance to corrosion, particularly in seawater. This makes it ideal for use in marine environments such as shipbuilding, offshore platforms, and desalination plants. CuNi34 is highly resistant to pitting, biofouling, and stress corrosion cracking, which are common challenges in marine applications. Its durability in aggressive environments helps ensure long-lasting performance in conditions that would typically degrade other materials.
The alloy also possesses good mechanical properties, offering strength, ductility, and toughness. While its electrical and thermal conductivity is lower than that of pure copper due to the nickel content, it still maintains adequate conductivity for certain industrial uses, such as heat exchangers and cooling systems.
CuNi34 is commonly used in pipes, tubes, and marine components, where its combination of corrosion resistance, mechanical strength, and resistance to harsh conditions is critical. It is a reliable and cost-effective material choice for industries requiring durable, corrosion-resistant solutions, especially in seawater or chemically aggressive environments.
Chemical Composition Wt.% | % | Ni | Cu | Mn |
Min | ||||
Max | 34 | Rest | 1 |
Main physical properties:
Max continuous operating temperature ℃ | 350 |
Resistance temperature coefficient x 10-5/℃(20℃-600℃) | <0 |
Thermovoltage to copper at 20℃ in μV/K | -39 |
Thermal expansion coefficient ×10-6/K(20℃-400℃) | 16.0 |
Thermal conductance at 20℃ W/mK | 25 |
Specific heat capacity at 20℃ J/gK | 0.40 |
Main technical data
Type | CuNi1 NC003 | CuNi2 NC005 | CuNi4 NC007 | CuNi6 NC010 | CuNi8 NC012 | CuMn3 MC012 | CuNi10 NC015 | CuNi14 NC020 | CuNi19 NC025 | CuNi23 NC030 | CuNi30 NC035 | CuNi34 NC040 | CuNi44 NC050 | |
Composition(%) | Cu | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest | Rest |
Mn | / | / | / | / | / | 3 | / | 0.3 | 0.5 | 0.5 | 1.0 | 1.0 | 1.0 | |
Ni | 1 | 2 | 4 | 6 | 8 | 10 | 14.2 | 19 | 23 | 30 | 34 | 44 | ||
Max.continuous operating temperature(℃) | 200 | 200· | 200 | 220 | 250 | 200 | 250 | 300 | 300 | 300 | 350 | 350 | 400 | |
Resistivity at 20℃(μ m) | 0.03 ±10% | 0.05 ±10% | 0.07 ±10% | 0.10 ±10% | 0.12 ±10% | 0.12 ±10% | 0.15 ±10% | 0.20 ±5% | 0.25 ±5% | 0.30 ±5% | 0.35 ±5% | 0.40 ±5% | 0.49 ±5% | |
Resisitance-temperature coefficient 20-600℃ (×10-5/℃) | < 100 | < 120 | < 50 | < 60 | < 57 | < 38 | < 50 | < 38 | < 25 | < 16 | < 10 | < -0 | < -6 | |
Thermovoltage to copper at 20℃ in (μV/K) | -8 | -12 | -12 | -18 | -22 | 1 | -25 | -28 | -32 | -34 | -37 | -39 | -43 | |
Mean coefficient of linear thermal expansion, in (10-6/K) , at a temperature between 20 ℃ and 400 ℃ | 17.5 | 17.5 | 17.5 | 17.5 | 17.5 | 18 | 17.5 | 17.5 | 17.5 | 17.5 | 17.0 | 16.0 | 15.0 | |
Thermal conductance at 20℃ (W/mK) | 145 | 130 | 130 | 92 | 75 | 84 | 59 | 48 | 38 | 33 | 27 | 25 | 23 | |
Specific heat capacity at 20℃ in (20℃ J/gK) | 0.38 | 0.38 | 0.38 | 0.38 | 0.38 | 0.39 | 0.38 | 0.38 | 0.38 | 0.38 | 0.39 | 0.40 | 0.41 | |
Density at 20 ℃(g/cm3) | 8.9 | 8.9 | 8.9 | 8.9 | 8.9 | 8.8 | 8.9 | 8.9 | 8.9 | 8.9 | 8.9 | 8.9 | 8.9 | |
Melting temperature in (℃) | 1085 | 1090 | 1090 | 1095 | 1097 | 1050 | 1100 | 1115 | 1135 | 1150 | 1170 | 1180 | 1280 | |
Min.tensile strength in (N/mm2) | 210 | 220 | 220 | 250 | 270 | 290 | 290 | 310 | 340 | 350 | 400 | 400 | 420 | |
Elongation(%) | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
Technical data table
Diameter(mm) | NC003 CuNi1 | NC005 CuNi2 | NC007 CuNi4 | NC010 CuNi6 | NC012 CuNi8 | NC015 CuNi10 | NC020 CuNi14 | NC025 CuNi19 | NC030 CuNi23 | NC035 CuNi30 | NC040 CuNi34 | NC050 CuNi44 |
0.10 | 3.82 | 6.36 | 8.91 | 12.73 | 15.28 | 19.09 | 25.46 | 31.83 | 38.19 | 44.56 | 50.93 | 62.39 |
0.11 | 3.16 | 5.26 | 7.37 | 10.52 | 12.63 | 15.78 | 21.04 | 26.30 | 31.56 | 36.82 | 42.09 | 51.56 |
0.12 | 2.65 | 4.42 | 6.19 | 8.84 | 10.61 | 13.26 | 17.68 | 22.10 | 26.52 | 30.94 | 35.37 | 43.33 |
0.13 | 2.26 | 3.76 | 5.27 | 7.53 | 9.04 | 11.30 | 15.07 | 18.83 | 22.60 | 26.36 | 30.14 | 36.92 |
0.14 | 1.95 | 3.24 | 4.55 | 6.49 | 7.80 | 9.74 | 12.99 | 16.24 | 19.48 | 22.73 | 25.98 | 31.83 |
0.15 | 1.70 | 2.82 | 3.96 | 5.65 | 6.79 | 8.48 | 11.31 | 14.14 | 16.97 | 19.80 | 22.64 | 27.73 |
0.16 | 1.49 | 2.48 | 3.48 | 4.97 | 5.97 | 7.46 | 9.95 | 12.43 | 14.92 | 17.40 | 19.89 | 24.37 |
0.17 | 1.32 | 2.20 | 3.08 | 4.40 | 5.29 | 6.60 | 8.81 | 11.01 | 13.21 | 15.41 | 17.62 | 21.59 |
0.18 | 1.18 | 1.96 | 2.75 | 3.92 | 4.72 | 5.89 | 7.86 | 9.82 | 11.78 | 13.75 | 15.72 | 19.26 |
0.19 | 1.06 | 1.76 | 2.47 | 3.52 | 4.23 | 5.29 | 7.05 | 8.81 | 10.58 | 12.34 | 14.11 | 17.28 |
0.20 | 0.95 | 1.59 | 2.23 | 3.18 | 3.82 | 4.77 | 6.36 | 7.95 | 9.54 | 11.14 | 12.73 | 15.60 |
0.21 | 0.87 | 1.44 | 2.02 | 2.88 | 3.46 | 4.33 | 5.77 | 7.21 | 8.66 | 10.10 | 11.55 | 14.15 |
0.22 | 0.79 | 1.31 | 1.84 | 2.63 | 3.16 | 3.94 | 5.26 | 6.57 | 7.89 | 9.20 | 10.52 | 12.89 |
0.23 | 0.72 | 1.20 | 1.68 | 2.40 | 2.89 | 3.61 | 4.81 | 6.01 | 7.22 | 8.42 | 9.63 | 11.79 |
0.24 | 0.66 | 1.10 | 1.55 | 2.21 | 2.65 | 3.31 | 4.42 | 5.52 | 6.63 | 7.73 | 8.84 | 10.83 |
0.25 | 0.61 | 1.01 | 1.43 | 2.03 | 2.44 | 3.05 | 4.07 | 5.09 | 6.11 | 7.13 | 8.15 | 9.98 |
0.26 | 0.57 | 0.94 | 1.32 | 1.88 | 2.26 | 2.82 | 3.77 | 4.70 | 5.65 | 6.59 | 7.53 | 9.23 |
0.27 | 0.52 | 0.87 | 1.22 | 1.74 | 2.10 | 2.61 | 3.49 | 4.36 | 5.23 | 6.11 | 6.99 | 8.56 |
0.28 | 0.49 | 0.81 | 1.14 | 1.62 | 1.95 | 2.43 | 3.25 | 4.06 | 4.87 | 5.68 | 6.50 | 7.96 |
0.29 | 0.45 | 0.75 | 1.06 | 1.51 | 1.82 | 2.27 | 3.03 | 3.78 | 4.54 | 5.29 | 6.06 | 7.42 |
0.30 | 0.42 | 0.70 | 0.99 | 1.41 | 1.70 | 2.12 | 2.83 | 3.53 | 4.24 | 4.95 | 5.66 | 6.93 |
0.31 | 0.40 | 0.66 | 0.93 | 1.32 | 1.59 | 1.98 | 2.65 | 3.31 | 3.97 | 4.63 | 5.30 | 6.49 |
0.32 | 0.37 | 0.62 | 0.87 | 1.24 | 1.49 | 1.86 | 2.49 | 3.11 | 3.73 | 4.35 | 4.97 | 6.09 |
0.33 | 0.35 | 0.58 | 0.82 | 1.17 | 1.40 | 1.75 | 2.34 | 2.92 | 3.51 | 4.09 | 4.68 | 5.73 |
0.34 | 0.33 | 0.55 | 0.77 | 1.10 | 1.32 | 1.65 | 2.20 | 2.75 | 3.30 | 3.85 | 4.41 | 5.40 |
0.35 | 0.31 | 0.51 | 0.73 | 1.03 | 1.25 | 1.55 | 2.08 | 2.60 | 3.11 | 3.63 | 4.16 | 5.09 |
0.36 | 0.29 | 0.49 | 0.69 | 0.98 | 1.18 | 1.47 | 1.96 | 2.46 | 2.94 | 3.43 | 3.93 | 4.81 |
0.37 | 0.28 | 0.46 | 0.65 | 0.93 | 1.12 | 1.39 | 1.86 | 2.33 | 2.79 | 3.25 | 3.72 | 4.56 |
0.38 | 0.26 | 0.44 | 0.62 | 0.88 | 1.06 | 1.32 | 1.76 | 2.20 | 2.64 | 3.08 | 3.53 | 4.32 |
0.40 | 0.24 | 0.39 | 0.56 | 0.79 | 0.95 | 1.19 | 1.59 | 1.99 | 2.38 | 2.78 | 3.18 | 3.90 |
0.41 | 0.23 | 0.37 | 0.53 | 0.76 | 0.91 | 1.13 | 1.51 | 1.89 | 2.27 | 2.65 | 3.03 | 3.71 |
0.42 | 0.22 | 0.36 | 0.51 | 0.72 | 0.87 | 1.08 | 1.44 | 1.80 | 2.16 | 2.52 | 2.89 | 3.54 |
0.43 | 0.21 | 0.34 | 0.48 | 0.69 | 0.83 | 1.03 | 1.38 | 1.72 | 2.06 | 2.41 | 2.75 | 3.37 |
0.44 | 0.20 | 0.32 | 0.46 | 0.66 | 0.79 | 0.98 | 1.31 | 1.64 | 1.97 | 2.30 | 2.63 | 3.22 |
0.45 | 0.19 | 0.31 | 0.44 | 0.63 | 0.75 | 0.94 | 1.26 | 1.57 | 1.88 | 2.20 | 2.52 | 3.08 |
0.46 | 0.18 | 0.30 | 0.42 | 0.60 | 0.72 | 0.90 | 1.20 | 1.50 | 1.80 | 2.10 | 2.41 | 2.95 |
0.47 | 0.17 | 0.28 | 0.40 | 0.58 | 0.69 | 0.86 | 1.15 | 1.44 | 1.72 | 2.01 | 2.31 | 2.82 |
0.48 | 0.17 | 0.27 | 0.39 | 0.55 | 0.66 | 0.82 | 1.10 | 1.38 | 1.65 | 1.93 | 2.21 | 2.71 |
0.49 | 0.16 | 0.26 | 0.37 | 0.53 | 0.64 | 0.79 | 1.06 | 1.33 | 1.59 | 1.85 | 2.12 | 2.60 |
0.50 | 0.15 | 0.25 | 0.36 | 0.51 | 0.61 | 0.76 | 1.01 | 1.27 | 1.52 | 1.78 | 2.04 | 2.50 |
0.51 | 0.15 | 0.24 | 0.34 | 0.49 | 0.59 | 0.73 | 0.98 | 1.22 | 1.46 | 1.71 | 1.96 | 2.40 |
0.52 | 0.14 | 0.23 | 0.33 | 0.47 | 0.57 | 0.70 | 0.94 | 1.18 | 1.41 | 1.65 | 1.88 | 2.31 |
0.53 | 0.14 | 0.22 | 0.32 | 0.45 | 0.54 | 0.67 | 0.91 | 1.13 | 1.35 | 1.59 | 1.81 | 2.22 |
0.54 | 0.13 | 0.22 | 0.31 | 0.44 | 0.52 | 0.65 | 0.87 | 1.09 | 1.30 | 1.53 | 1.75 | 2.14 |
0.55 | 0.13 | 0.21 | 0.29 | 0.42 | 0.51 | 0.63 | 0.84 | 1.05 | 1.26 | 1.47 | 1.68 | 2.06 |
0.56 | 0.12 | 0.20 | 0.28 | 0.41 | 0.49 | 0.60 | 0.81 | 1.02 | 1.21 | 1.42 | 1.62 | 1.99 |
0.57 | 0.12 | 0.19 | 0.27 | 0.39 | 0.47 | 0.58 | 0.78 | 0.98 | 1.17 | 1.37 | 1.57 | 1.92 |
0.58 | 0.11 | 0.19 | 0.27 | 0.38 | 0.45 | 0.56 | 0.76 | 0.95 | 1.13 | 1.32 | 1.51 | 1.85 |
0.59 | 0.11 | 0.18 | 0.26 | 0.37 | 0.44 | 0.54 | 0.73 | 0.91 | 1.09 | 1.28 | 1.46 | 1.79 |
0.60 | 0.11 | 0.18 | 0.25 | 0.35 | 0.42 | 0.53 | 0.71 | 0.88 | 1.06 | 1.24 | 1.41 | 1.73 |
Some key features of CuNi34 include:
CuNi34 exhibits excellent resistance to seawater corrosion and is commonly used in marine engineering, such as shipbuilding, offshore structures, and desalination plants.
It resists biofouling (accumulation of marine organisms) and is less prone to pitting corrosion compared to other copper alloys.
The alloy has good strength, ductility, and toughness.
It has moderate strength but remains highly resistant to stress corrosion cracking, especially in marine or aqueous environments.
While copper is known for its high electrical conductivity, CuNi34 has lower conductivity than pure copper due to the presence of nickel.
It retains reasonable thermal conductivity, which can be useful in heat exchange applications.
Applications: