ASTM B111 C71500 | CuNi 70/30 Condenser Tubing

The ASTM B111 C71500 seamless condenser tubes are made from a copper-nickel alloy that contains approximate 70% Cu and 30% Ni in weight percent. Its nominal composition was once designated as “Cu-30Ni-0.5Fe” or “70Cu-30Ni”. Hence they are also called “CuNi 70/30 condenser tubing“. Similar to C70600, C71500 is among the most corrosion resistant and thermally stable of all the copper alloys, and are virtually immune to stress corrosion cracking (SCC). The ASTM B111 C71500 tubes are mostly produced for condensers in ships and seacoast power stations. They are also widely used for evaporators, distillers and heat exchangers in seawater desalination plants.

The ASTM B111 C71500 seamless condenser tubes supplied to a French client; O61 temper, O.D.=25.4mm, W.T.=2.77mm, L=6096mm; 3rd-party inspection conducted by Bureau Veritas.

Chemical Composition Requirements

The chemical composition requirements for condenser tubes made of ASTM B111 C71500 are specified in weight percent (%): Nickel + Cobalt: 29.0~33.0; Lead: ≤0.02; Iron: 0.40~1.00; Zinc: ≤0.50; Manganese: ≤1.00; Phosphorous: ≤0.02; C≤0.05; S≤0.02; Copper: remainder.

Mechanical Properties

ASTM B111 C71500 (CuNi 70/30) condenser tubes supplied to Port of Durban, South Africa.

The ASTM B111 C71500 condenser tubing can be furnished in two temper designations based on the final heat treatment: O61 (annealed) and, HR50 (drawn and stress-relieved). The mechanical properties of tubes vary with different temper designations / heat treatments.

• For O61 temper: tensile strength ≤ 52 ksi [360 MPa], yield strength ≤ 18 ksi [125 MPa].
• For HR50 temper: If wall thickness ≤ 0.048″ [1.2 mm], tensile strength ≤ 72 ksi [495 MPa], yield strength ≤ 50 ksi [345 MPa], elongation in 2″ ≤ 12%. If wall thickness ＞ 0.048″ [1.2 mm], tensile strength ≤ 72 ksi [495 MPa], yield strength ≤ 50 ksi [345 MPa], elongation in 2″ ≤ 15%.

International Equivalent

ASTM B111 UNS C71500 has the following international equivalent grades: Grade BFe30-1-1 of Chinese standard; Gr. CN107 of BS 2871-2; 2.0882 of DIN 17664; CuNi30Mn1Fe (CW354H) of EN 12449; JIS H: C7150; MIL-T-15005, MIL-T-16420, MIL-T-22214.

Inspection & Testing

The induction melting furnace for white copper. It is a basic equipment for the manufacture of C71500 tubes from scratch.

Similar to other copper and copper alloy tubes, the following inspection and tests shall be conducted on ASTM B111 UNS C71500 seamless condenser tubes: grain size determination, expansion test, flattening test, residual stress test (optional), eddy current test, hydrostatic test, dimensional inspection (diameter, wall thickness, length, end cut), as well as visual examination.