| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a clad material for a welded tube of a heat exchanger made from aluminum alloys, which has an improved low-cycle flex fatigue strength, is superior in a high-cycle fatigue strength as well, and has adequate brazing properties and corrosion resistance. <P>SOLUTION: The clad material is a three-layer clad material comprising: a core material which comprises 0.3-1.2% Si, 0.3-1.0% Cu, 0.6-1.8% Mn, less than 0.05% Mg which is an impurity limited to the content, and the balance Al with unavoidable impurities; an inner skin material which clads one surface of the core material and comprises 0.3-1.2% Si, 0.6-1.8% Mn, 0.5-5% Zn, less than 0.05% Mg which is an impurity limited to the content, and the balance Al with unavoidable impurities; and a brazing filler metal which clads the other surface of the core material and comprises 6-12% Si, and the balance Al with unavoidable impurities, wherein the hardness of the core material after having been heated for brazing is 50 Hv or more, the hardness of the inner skin material is 50 Hv or more, and the ratio of the hardness of the inner skin material to that of the core material (inner skin material hardness/core material hardness) is less than 1.0. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
