C71500 white copper standard: ASTM B111M-1992, B122-1990, B151M-19889, B466M-1986
C70600 has good cold and hot processability. C71500 white copper is mainly used as condenser tubes, distiller tubes, and heat exchanger casings.
chemical composition:
Copper + alloy element Cu: ≥99.5
Copper+Silver Cu+Ag: ≤65.5
Lead Pb: ≤0.05①
Iron Fe: 0.40~1.0
Zinc Zn: ≤1.0①
Nickel Ni: 29.0~33.0
Manganese Mn: ≤1.0
White copper alloy has good solderability. However, this welding method is rarely used because the joint strength obtained by this welding method does not meet the actual service requirements of cupronickel alloy, and it will aggravate galvanic metal corrosion in corrosive environments. Traditional brazing methods can be used, and it is recommended to use high-silver filler metal, which can minimize the chance of corrosion of the white copper alloy. Copper-phosphorus and copper-silver-phosphorus solders should not be used because their use increases the risk of intergranular corrosion and hydrogen embrittlement. Heavy cold-processed white copper alloy materials should be recrystallized and annealed before brazing to avoid excessive penetration and cracking between the brazing alloy and the base metal.
Heat exchangers require higher thermal conductivity than ordinary equipment and sometimes use finned tubes. Compared with ordinary pipes, finned tubes have a larger heat exchange area per unit length. The finned tubes can be made into various shapes and sizes, including inner tubes and outer tubes. Depending on the service conditions, the pipe materials required to manufacture heat exchangers are also different. When conducting seawater cooling, white copper alloy is the most suitable material, especially the pipe material, which is the most critical part of the heat exchanger.