| 摘要 |
PROBLEM TO BE SOLVED: To improve the original sheet strength and high temp. buckling resistance by allowing a material to have a specified compsn. contg. Mn, Si, Zn, Cu and Fe and controlling the content of intermetallic compds. of the specified size, the average crystal grain size in the surface after brazing heating and the sheet thickness and tensile strength to specified ranges. SOLUTION: This fin material is composed of, by weight, 0.8 to 2.0% Mn, 0.2 to 0.6% Si, 0.4 to 2.0% Zn, <=0.03% Cu, <=0.2% Fe, and the balance Al with inevitable impurities. Then, it contains intermetallic compds. of 0.02 to 0.3μm size by >=600 pieces/μm3, and, moreover, the content of intermetallic compds. of >=3μm size is controlled to <=500 pieces/mm2. Furthermore, the average crystal grain size in the surface after brazing heating is controlled to >=0.4 mm, the sheet thickness to 0.03 to 0.10 mm, and the tensile strength to >=200 N/mm2. This fin material may be used as a bear material as it is but may be used in the state of being clad with a brazing filler metal of Al-Si series or the like as well.
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