| 摘要 |
PURPOSE:To improve the external part corrosion resistance of a product by cladding the brazing sheet metal of Al-Si, etc., contg. more than one kind of Cu and Mn at specified wt.% to an Al-Mn-Cu core metal and regulating the potential difference within specified range. CONSTITUTION:The Al-Si or Al-Si-Mg alloy brazing sheet metal contg. more than one kind at least of 0.05-1.0wt.% Cu and 0.05-1.0wt.% Mn is prepd. for a sheath material. This is cladded to the core material made of Al-Mn-Cu alloy and the potential difference in the core material and sheath material is regulated within the range of 10-30mV. In this case, the clad rate of the filler metal is taken at 2-20% and the crystal grain size of the core material is adjusted in the necessary value as well. due to the potential difference between the core material and brazing filler metal being regulated the corrosing speed of the brazing sheet metal at the fillet part of the product of a heat exchanger, etc. is constrained. Consequently the external part corrosion resistance of a product is improved.
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