Patent ID: 8561682
Filing Date: 2013-10-22
Classification: B23K,B32B,C22C,F28D,F28F,Y10T

Abstract:
1. A tube for a heat exchanger, the tube being formed by bending a three-layer clad material of an aluminum alloy to have an overlapped portion bonded by brazing, the three-layer clad material comprising: a core material layer containing therein Mg equal to or larger than 0.2 wt % after the brazing; a brazing material layer provided on a first surface of the core material layer, wherein the brazing material layer has a thickness equal to or larger than 25 μm before the brazing, and has a melting point lower than 600° C.; and a high melting-point material layer provided on a second surface of the core material layer opposite the first surface, the high melting-point material layer having a melting point equal to or higher than 600° C., wherein the brazing material layer and the high melting-point material layer are in direct contact with each other in the overlapped portion, and are bonded to each other in the overlapped portion by the brazing at a brazing temperature not lower than 450° C. for a time within 12 minutes; and the overlapped portion includes a first high melting point material layer, a first core material layer, a first brazing material layer, a second high melting point material layer, a second core material layer and a second brazing material layer in this order from an inside of the tube to an outside of the tube.