PURPOSE: To obtain a fin material excellent in strength and thermal conductivity after brazing heating as well as in drooping resistance at the time of brazing heating by using an Al alloy in which specific amounts of Si, Fe, and Zr are incorporated and also specifying respective conditions in homogenizing treatment, cold rolling, and annealing.
CONSTITUTION: An ingot of an Al alloy having a composition consisting of, by weight, 0.03-0.5% Si, 0.03-0.3% Fe, 0.03-0.2% Zr, and the balance Al is subjected to homogenizing treatment at 450-550°C for 1-30hr. Subsequently, this alloy is hot-rolled and then subjected to cold working and to process annealing in which the area ratio of recrystallization is regulated to ≥80% at 370-500°C, and further, cold draft from the final annealing to the final sheet thickness is regulated to 30-90%. By this method, the superior fin material well balanced among characteristics, such as drooping resistance at the time of brazing heating and strength and thermal conductivity after brazing heating can be obtained.
DOKOU TAKENOBU
ISHIKAWA KAZUNORI
ASAMI SHIGENORI
Next Patent: HEAT TRANSFER PIPE FOR HEAT EXCHANGER