Copper alloy and method for its manufacture
The invention relates to a copper alloy having high recrystallization temperature and good conductivity used in brazed heat exchangers which alloy consists of 0.1 to 0.3% in weight chromium. The invention also relates to a method for the manufacturing of the alloy which method consists of the following steps: casting, cold working, annealing and another cold working before brazing.
1. A method of manufacturing an automotive heat exchanger, comprising:
forming fin material of a copper alloy consisting of copper, 0.1 to 0.3% by weight chromium and incidental impurities by casting, a first cold working, annealing and a second cold working, whereby the recrystallization temperature of the alloy is at least 625° C., and
brazing the fin material to a heat exchanger tube,
wherein the casting step is a continuous strip casting step, the first cold working step is a rolling step, the annealing step is a strand annealing step that is carried out for a time up to 30 seconds at a temperature in the range from 700 to 900° C., and the second cold working step is a rolling step.
2. A method according to claim 1 , wherein the alloy contains 0.15 to 0.25% by weight chromium.
3. A method according to claim 1 , wherein the strand annealing step is carried out for a time in the range from 1 to 10 seconds.