| 摘要 |
PURPOSE:To enhance the pitting corrosion resistance of brazed portions by using an Al alloy of a specified composition as a brazing filler metal when a brazing sheet obtd. by cladding Al as a core material with the brazing filler metal is brazed to an Al tube or the like. CONSTITUTION:In the manufacture of a heat exchanger a brazing sheet as fin material 1 obtd. by cladding Al or an Al alloy as a core material with an Al alloy as a brazing filler metal is brazed to Al or Al alloy tube 2. The Al alloy as the brazing filler metal contains 3-15% Si, 0.5-5.0% Mg, 0.3-4.0% Zn, 0.01-0.5% Bi and 0.01-0.5% Sn or further contains 0.02-0.3% In and/or 0.02-0.3% Ga and shows superior fluidity. This alloy has natural electric potential lower than that of the body to be brazed, and the occurrence of pitting corrosion in the brazed body can be prevented. |
