What is c71500 copper nickel 70/30?

c71500 copper nickel (also known as CDA 715 or 70/30 cupronickel) is a wrought copper-nickel alloy containing approximately 30% nickel with important additions of iron and manganese. These iron and manganese additions are necessary to maintain good corrosion resistance in marine salt water environments.

Why iron and manganese matter for buyers: These elements are required for good corrosion resistance in seawater. Do not accept material with insufficient iron content (below 0.40%).

Tube (Annealed – OS035 temper)

Tube (Light annealed – OS025 temper)

Rod (Half hard – H02 temper, 1" diameter)

Flat Products (Annealed, 1" thickness)

c71500 density = 0.323 lb/in³ (8.94 g/cm³ at 20°C).

Marine Applications

Salt water flanges, piping, and fittings

Seawater condensers and heat exchangers

Valve bodies for sea water service

Water boxes – salt water applications

Pump bodies and internal parts for sea water

Propeller sleeves

Industrial Applications

Pump impellers

Heat exchanger tubes, evaporator tubes, distiller tubes

Condenser plates and components

Ferrules and welding backing rings

Flexible metal hose and weld wire

Boiler parts and process equipment

Q1: What is the difference between C71500 and C70600?

C71500 (70/30) has higher strength and better erosion resistance than C70600 (90/10). C71500 contains 30% nickel vs 10% in C70600. Based on typical mechanical data, C71500 tensile strength is 372-517 MPa compared to approximately 303-414 MPa for C70600. C71500 is recommended for higher velocity seawater (4-5 m/s) while C70600 is limited to 3-3.5 m/s. However, C71500 is more expensive – typically 25-30% higher cost.

Q2: What ASTM standards cover C71500 seamless pipe and tube?

ASTM B111 covers seamless condenser tube, and ASTM B466 covers seamless pipe for general service. For ASME code applications (pressure vessels, boilers), use ASME SB111 for tube and ASME SB466 for pipe. Military applications require MIL-T-16420K (designation 771506). Always confirm the exact standard and revision on your purchase order.

Q3: What is the density of C71500 material in lb/in³ and g/cm³?

Density is 0.323 lb/in³ at 68°F or 8.94 g/cm³ at 20°C. Use this for weight calculations. For a 1" OD × 0.065" wall C71500 copper pipe, weight is approximately 0.65 lb per foot. Always calculate using actual OD and wall thickness as small variations significantly affect total weight for large piping systems.

Q4: What is the machinability rating of 70/30 copper nickel?

Machinability rating is 20% (free-machining brass = 100%). This means C71500 is relatively difficult to machine. Use sharp carbide tooling, lower cutting speeds, and abundant coolant. For complex components like valve bodies or pump housings, consider purchasing finished machined parts directly from the mill rather than machining bar stock in-house.

Q5: What welding processes are suitable for C71500 copper pipe?

Gas shielded arc welding (TIG/MIG), coated metal arc welding (MMA), butt welding, seam welding, and spot welding are all excellent. Oxyacetylene welding is good. Brazing and soldering are also excellent. For seawater service, TIG welding with ERNi-7 filler metal and argon back-purge is recommended for root pass to avoid oxidation.

Q6: What is the thermal conductivity of 70/30 copper nickel?

Thermal conductivity is 17.0 Btu·ft/(hr·ft²·°F) at 68°F (29.4 W/m·K at 20°C). This is approximately 1/12 that of pure copper (C12200 at ~340 W/mK). For heat exchanger applications, this lower conductivity requires more surface area compared to pure copper. However, the alloy's superior seawater corrosion resistance often justifies the design trade-off.

Q7: What is the yield strength of C71500 annealed tube?

For annealed tube (OS035 temper), yield strength is not specified but tensile strength is 54 ksi (372 MPa) minimum with 45% elongation. For light annealed tube (OS025 temper), yield strength (0.2% offset) is 25 ksi (172 MPa) with tensile strength 60 ksi (414 MPa). Always request a mill certificate to confirm actual properties for your specific heat number.

Q8: What are the equivalent European standards for C71500?

EN 12449 CW354H is the European standard for seamless tube. DIN 17664 CuNi30Mn1Fe is the German standard. DIN 86019 WL2.1972 is the German naval standard. BS 2871 Part 2 CN107 is the British standard. For European projects, specify EN 12449 CW354H and request dual certification (ASTM + EN) if needed.

Q9: Does C71500 contain iron and why is it important?

Yes, C71500 contains 0.40-1.0% iron per ASTM specifications. Iron is a necessary addition to maintain good corrosion resistance in seawater. Iron modifies the protective passive film on the alloy surface. When buying C71500 for marine service, always verify that iron content meets the minimum 0.40% requirement – binary Cu-30Ni without iron has inferior seawater corrosion resistance.

Q10: Can C71500 be used for salt water flanges and valve bodies?

Yes, C71500 is commonly used for salt water flanges, valve bodies, pump bodies, and fittings. It is one of the main materials specified for seawater service applications. The alloy provides excellent resistance to salt water corrosion and is immune to chloride stress-corrosion cracking, unlike stainless steels. Both cast and wrought forms are available.

Marking per bundle:

Alloy: C71500 (CDA 715)

Heat number (traceable to mill certificate)

Size: OD × wall thickness

Length and quantity

Purchase order number

Net weight and gross weight

Discuss Your Project Requirements