Process of producing lightweight and corrosion-resistant heat exchanger

A method of producing a lightweight and corrosion-resistant heat exchanger, comprising the steps of:

• forming a tube having a plurality of passage bores by extrusion form one of aluminum and an aluminum alloy;
• coating at least a part of the outer periphery of said tube, as viewed in cross-section, with a layer of a brazing material with the aid of a non-corrosive flux applied to one of said tube and said layer such that said layer of brazing material extends over the entire length of said tube, said brazing material comprising an aluminum alloy including zinc silicon and having an electrode potential value lower than that of the material of said tube;
• bending said tube into a substantially zigzag winding form such that the bent tube has a plurality of substantially parallel runs and a plurality of bent portions each interconnecting an adjacent pair of said runs;
• placing corrugated fin members of one of aluminum and an aluminum alloy between adjacent runs of said tube, respectively, such that said fin members are not in contact with said bent portions of said tube, said fin members being uncoated with any layer of brazing material and each having a thickness of less than 0.12 mm;
• and
• heating said tube and said corrugated fin members at least to the melting point of said brazing material to bond said corrugated fin members to said tube by said brazing material.