ASTM B111 ASME SB111 C71500 Copper Nickel Tubes

Suitable for high temperature service

Primarily used in seawater operations requiring forged and machined pump and valve components, hardware and fittings

Can also be widely used in areas requiring high corrosion resistance

Used where chloride stress-corrosion cracking precautions prevent usage of stainless steel

Typical applications: Condenser for ship, heat and water supply, chemical industry, desalinator, condensers, seawater piping, power plants, heat exchanger shells.

Selection guidance: Choose C71500 for higher strength requirements, high-velocity seawater up to 4.5 m/s, and applications where additional corrosion resistance is needed. Choose C70600 for general marine service where lower strength is acceptable and cost is a factor.

Higher strength than C70600 – Tensile strength 52 ksi min (annealed) vs 40 ksi for C70600

Suitable for high temperature service – Per the page specification

Excellent seawater corrosion resistance – Primary use in seawater operations for pump and valve components

Alternative to stainless steel – Used where chloride stress-corrosion cracking prevents use of stainless steel

Multiple international approvals – Meets ASTM, ASME, BS, DIN, JIS, GB, MIL, and NES standards

Condensers for ships

Heat and water supply systems

Chemical industry equipment

Desalination plants

Seawater piping

Power plants

Heat exchanger shells

Forged and machined pump and valve components

Hardware and fittings

Water desalting plants (with C70600)

Q1: C71500 vs C70600 – which one has higher tensile strength?

C71500 has higher tensile strength. C71500 annealed tube has minimum tensile strength of 52 ksi (360 MPa), while C70600 annealed tube has minimum 40 ksi (275 MPa). The 30% nickel content in C71500 provides this strength advantage. For high-pressure or high-temperature applications where stronger material is required, choose C71500 over C70600.

Q2: What is the density of C71500?

C71500 density is 8.94 g/cm³ (0.323 lb/in³). This density is similar to other copper-nickel alloys. For tube weight calculation, use the formula (OD - wall) × wall × 10.68 = lb per foot. A 1" OD × 0.065" wall C71500 tube weighs approximately 0.65 lb per foot.

Q3: What tempers are available for C71500 tube?

C71500 tube is available in O61 annealed temper and HR50 drawn and stress-relieved temper. O61 annealed has minimum tensile strength of 52 ksi and is best for bending and tube expansion. HR50 drawn and stress-relieved has minimum tensile strength of 72 ksi with 50 ksi yield strength. For wall thickness up to 0.048", elongation is 12%; for wall over 0.048", elongation is 15%.

Q4: What is the melting point of C71500?

C71500 melting point is 1171°C (2140°F). This relatively high melting point allows the alloy to retain strength at elevated temperatures. For comparison, pure copper melts at 1085°C (1985°F). The higher nickel content in C71500 raises the melting point compared to C70600.

Q5: What expansion requirement does C71500 tube need to meet?

Annealed C71500 tube must expand 30% of original OD without cracking. Drawn and stress-relieved (HR50) tube must expand 20% of original OD without cracking. This expansion test ensures the tube has sufficient ductility for rolling into tubesheets and for flare fittings. Tubes that crack during expansion are rejected.

Q6: What European standards cover C71500?

EN 12451 CuNi30Mn1Fe and DIN 17664 2.0882 are the European standards for C71500. BS 2871 CN107 is the British standard. The German designation is CuNi30Mn1Fe with material number 2.0882. When ordering for European projects, specify EN 12451 or DIN 17664 to ensure compliance with local regulations.

Q7: Is C71500 used for high temperature service?

Yes, C71500 is suitable for high temperature service. The alloy retains good mechanical properties and creep resistance at elevated temperatures up to 350°C (662°F). Typical high temperature applications include power plant condensers, feedwater heaters, and heat exchangers where steam temperatures are high.

Q8: What military specification covers C71500 tube?

MIL-T-16420K C71500 is the military specification for seamless tube. The requirements include nickel content of 29.0-33.0%, iron content of 0.4-1.0%, manganese maximum 1.0%, and copper minimum 65.0%. For naval shipbuilding and submarine applications, specify MIL-T-16420K to meet military quality requirements.

Q9: What is the Chinese equivalent of C71500?

BFe30-1-1 per GB/T8890 is the Chinese equivalent of C71500. The Chinese standard GB/T8890 covers seamless copper alloy heat exchanger tubes. BFe30-1-1 contains 30% nickel and 1% iron, matching the composition of C71500. When sourcing from Chinese mills or selling to Chinese customers, specify BFe30-1-1.

Q10: What size range is available for C71500 seamless tube?

C71500 seamless tube is available from 3mm to 70mm OD with wall thickness from 0.2mm to 5mm. Standard imperial sizes include 1/4", 3/8", 1/2", 5/8", 3/4", and 1" OD with wall thicknesses of 0.035", 0.049", 0.065", and 0.120". Length is typically per condenser and heat exchanger design requirements.

Chemical analysis: Composition tested to Table 1 requirements: Ni 29.0-33.0%, Fe 0.4-1.0%, Pb 0.02% max, Zn 0.50% max.

Tensile testing: Per ASTM E8/E8M. Requirements per Table 2/3: O61 temper (52 ksi min, 18 ksi min yield), HR50 temper (72 ksi min, 50 ksi yield).

Expansion test: Per ASTM B153. C71500 annealed tube expands 30% of original OD without cracking. HR50 tube expands 20%.

Flattening test: Specimens flattened at three places along length, rotated 1/3 turn between flats. Flattened area must allow micrometer set at 3× wall thickness to pass freely.

Grain size (annealed temper): Average grain size 0.010 to 0.045 mm per ASTM E112. Must show uniform and complete recrystallization at 75 diameters magnification.

Nondestructive testing – Eddy current: Each tube tested per ASTM E243. Calibration per Tables 5-8 in the specification.

Hydrostatic test alternative: Pressure calculated by formula P = 2St/(D - 0.8t) with allowable stress 7000 psi (48 MPa). Not required to exceed 1000 psi unless specified.

Pneumatic test alternative: Internal air pressure of 60 psig (400 kPa) minimum for 5 seconds without leakage.

Residual stress test (when specified): Mercurous nitrate test (ASTM B154) or ammonia vapor test (ASTM B858) with risk level pH 10.

Standard export package: As shown on the page, C71500 Copper Nickel Alloy Seamless Tubes are packed in standard export packaging.

Typical packaging includes:

Hexagonal bundles with steel straps

Plywood separators between layers

Plastic end caps on tube ends

Wooden crates for cut lengths (ISPM-15 certified)

Steel reels for coiled tube

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

Manufacturing process: Produced by processes such as casting, extrusion, drawing, annealing, straightening, and trimming which produce a seamless tube in the specified condition.

Melting: Induction melting with composition control for Ni 29.0-33.0%, Fe 0.4-1.0%.

Casting: Continuous casting produces billet.

Extrusion: Press pierces billet to hollow shell.

Cold drawing: Multiple draw passes achieve final dimensions.

Annealing: Furnaces at appropriate temperatures produce O61 annealed temper.

Stress relieving: Lower temperature treatment produces HR50 drawn and stress-relieved temper.

Straightening: Straightening machines achieve specified straightness.

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