Cu-Ni 715 (UNS C71500) – C71500 Copper Pipe

c71500 copper pipe is a copper-nickel alloy that is resistant to corrosion in seawater. This copper nickel 70/30 has good fatigue strength and relatively high thermal conductivity.

Key characteristics:

Readily formed in the annealed temper

Can be joined by standard welding, brazing and soldering processes

Good fatigue strength

No magnetic attraction

c71500 mechanical properties for pipe (typical values):

c71500 density = 0.322 lbs/in³ (approximately 8.92 g/cm³).

70/30 copper nickel is readily formed in the annealed temper. The alloy can be joined by standard welding, brazing and soldering processes.

Welding methods suitable:

TIG (GTAW)

MIG (GMAW)

Coated metal arc welding (MMA)

Resistance welding

Filler metal recommendation: Use ERNi-7 for best corrosion match.

Seawater piping systems

Heat exchangers and condensers

Flexible metal pipe systems

Marine and offshore applications

Power plant cooling systems

Desalination plants

Q1: What is the difference between C71500 pipe and C70600 pipe for seawater?

C71500 pipe has higher strength and better high-velocity erosion resistance than C70600 pipe. C71500 (70/30) has 70% copper, 30% nickel with UTS 65,000 PSI (annealed) vs C70600 at approximately 50,000-55,000 PSI. C71500 handles seawater flow up to 4-5 m/s; C70600 is limited to 3-3.5 m/s. For higher velocity or more turbulent conditions, choose C71500. For lower velocity and budget-sensitive projects, C70600 is acceptable.

Q2: What is the density of C71500 material for pipe weight calculation?

C71500 density is 0.322 lbs/in³ (approximately 8.92 g/cm³). For pipe weight calculation: (OD - wall) × wall × 10.68 = lbs per foot. For metric: (OD mm - wall mm) × wall mm × 0.028 = kg/m. This density contributes to good pressure tightness.

Q3: Can C71500 copper pipe be welded?

Yes, C71500 copper pipe can be welded using standard processes including TIG, MIG, and resistance welding. The alloy is readily joined in the annealed temper. For seawater service, use ERNi-7 filler metal and argon back-purge for the root pass. Brazing and soldering are also suitable.

Q4: What is the tensile strength of C71500 pipe in annealed condition?

Annealed C71500 pipe has minimum tensile strength of 65,000 PSI (approximately 448 MPa). Yield strength (0.2% offset) is 35,000 PSI with 30% elongation. For cold drawn or half-hard temper, tensile strength can reach 100,000 PSI but elongation drops to 2%. Choose temper based on formability requirements.

Q5: What is the thermal conductivity of 70/30 copper nickel?

Thermal conductivity of 70/30 copper nickel is 29.4 W/m·K at room temperature. This is approximately 1/12 that of pure copper (C12200 at ~340 W/m·K). For heat exchanger applications, this lower conductivity requires more surface area, but the alloy's superior seawater corrosion resistance makes it the preferred choice for marine condensers.

Q6: Does C71500 have any magnetic properties?

No, C71500 has no magnetic attraction. This is important for applications requiring non-magnetic materials, such as near sensitive electronic equipment or for certain naval applications.

Q7: What is the melting point of C71500?

Melting point of C71500 is approximately 1170°C (2140°F). For processing, hot working temperature range is 925-1025°C (1700-1875°F). Annealing temperature is 650-815°C (1200-1500°F). These temperatures are important for fabrication planning.

Q8: How does C71500 compare to C17200 beryllium copper for corrosion resistance?

C71500 has superior seawater corrosion resistance compared to C17200 beryllium copper. C71500 is specifically designed for marine environments with iron and manganese additions for passive film stability. C17200 has higher strength but lower corrosion resistance in saltwater. For seawater piping and marine components, C71500 is the better choice.

Q9: What is the electrical resistivity of C71500?

Electrical resistivity of C71500 is 41.2 Microhm·cm at room temperature. Electrical conductivity is approximately 5% IACS. This relatively low conductivity (compared to pure copper) means C71500 is not typically used for electrical applications but is acceptable for anti-static or grounding purposes in marine systems.

Q10: Can C71500 be used for flexible metal pipe systems?

Yes, C71500 is used mainly for flexible metal foil heaters in strip form. For flexible metal pipe or hose applications, the alloy's good fatigue strength and formability in annealed temper make it suitable. The alloy can be formed and welded into flexible pipe assemblies for marine or industrial fluid handling.

Marking per bundle: Alloy (C71500 / 70/30), heat number, size (OD × wall), length, quantity, PO number, net/gross weight.

Moisture protection: Desiccant bags for tropical or long-term storage.

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