Akira Kawahara, Akio Niikura and Takeyoshi Doko
The authors have developed and put into practical use an aluminum alloy fin stock for automobile heat exchangers that satisfies the requirements for high strength and high thermal conductivity. This fin stock is an Al-Fe-Ni-Si alloy manufactured by the twin-roll continuous casting method, whereby the mechanical strength is increased by finely and densely enhancing dispersion of intermetallic compounds.
The fin stock developed here with a thickness of 0.06mm has, after brazing process at 600°C for 3 min, a tensile strength of 130 MPa and an electrical conductivity of 50 % IACS. For comparison, 3000-series alloys widely used for automobile heat exchangers have, under the same conditions, approximately a tensile strength of 110 MPa and an electrical conductivity of 40 % IACS. Thus the new fin stock has achieved a strength increase while maintaining an electrical conductivity equivalent to that of 1000-series alloys, enabling thickness reduction of fin stocks for heat exchangers.