| 摘要 |
PROBLEM TO BE SOLVED: To surely and stably manufacture a precoat fin material excellent in adhesibility of a coating film and anti-corrosion without causing formation defects even if volatile press oil of low viscosity is used to form it when manufacturing the precoat fin material for a heat exchanger by applying coating type chromate liquid to the surface of an aluminum alloy base material before baking it to form a coating type chromate coating film before forming a hydrophilic coating film on the surface of the coating type chromate coating film. SOLUTION: Time between the application of coating type chromate to the surface of base material and the start of heating for baking is controlled to 0.5 sec-60 sec. Next, when applying coating type chromate liquid to the surface of the base material, temperature of the chromate liquid on its application is controlled to 10 deg.C-45 deg.C. Further, when, after the coating type chromate liquid is applied to the surface of the base material, performing heating for baking, the temperature rise speed is controlled to 1 deg.C/sec-75 deg.C/sec.
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