| 摘要 |
PROBLEM TO BE SOLVED: To provide an aluminum alloy piping material for a heat exchanger having excellent corrosion resistance and its manufacturing method. SOLUTION: The aluminum alloy piping material for the heat exchanger has periodic high concentration layers of Ti and V in a thickness direction in which Mn-based deposits of≤0.2μm exist at 5×10<SP>5</SP>pieces/mm<SP>2</SP>in a matrix and further, the self-potential in an aqueous 5% NaCl solution is -740 to -900 mVvsSCE. Ti and V are divided the high concentration layers and low concentration layers, which layers are alternately distributed in laminar form in the thickness direction and the low concentration layers preferentially corrode as compared to the high concentration layers and the corrosion form is made laminar, and as a result thereof, the progression of the corrosion in the thickness direction is obstructed and the pitting resistance of the material is improved. COPYRIGHT: (C)2009,JPO&INPIT
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