PURPOSE: To provide the title fin material with excellent buckling resistance to the heating for brazing and high heat conductivity by regulating an Al alloy contg. specific amounts of Mn, Fe and Si and contg. specific numbers or above of secondary phase grains in the structure at the time of heating to the core and cladding Al or an Al alloy thereto.
CONSTITUTION: The core of a composite fin material is formed with an Al alloy contg., by weight, 0.6W2.0% Mn, 0.05W0.8% Fe and ≤0.6% Si. The core contains, per mm3, 30×109 pieces or above of secondary phase grains in the structure when heated for 10min at 610°C. An Al surface material having ≥99.9% purity or an Al alloy surface material contg. 0.03W0.35% Zr is clad to the one face or both faces of the core to form the clad fin material for a heat exchanger. By this method, excellent sagging resistance and high-temp. buckling resistance can be obtd. and a fin can be thinned.
ISHIKAWA KAZUNORI
ASAMI SHIGENORI
