| 摘要 |
The invention concerns a method for arc-welding of at least a metal workpiece (1) on a matrix (2) comprising at least a brazed zone (3) whereof the brazing contains copper and phosphorus, which comprises the following steps: (a) producing on at least part of the brazed zone (3), a deposition of at least a layer (5, 6, 7) of pure copper or of a copper alloy for which the phosphorus solubility limit is between about 0.1 and 3.5% at solidification temperature; and (b) welding the metal workpiece (1) on said at least one copper layer (5, 6, 7) deposited in step (a). The invention also concerns a method for making a brazed heat exchanger using such a welding process. The invention further concerns the resulting heat exchangers and their use in cryogenic gas separation, in particular air separation in a cryogenic separating unit.
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