Twenty-four experimental alloys were developed and evaluated as container materials or welding alloys for use with Sulfex and Niflex decladding solutions.nNiflex solutions, which were more corrosive than Sulfex solutions to most of the experimental alloys, produced severe localized attack at weldments made on vacuum-melted Hastelloy F with the experimental alloys. However, several of the alloys, when self-welded, were not selectively attached. Some of these showed a substantial improvement in resistance to the decladding solutions.nThe most promising alloys were based on either 45 w/o nickel-22 w/o chromium or 50 w/o nickel-25 w/o chromium, with at least 6 w/o molybdenum, and 1 w/o titanium, 0.6 w/o manganese, 0.4 w/o silicon, 0.02 w/o carbon, and balance iron. The alloy most resistant to both solutions contained 6 w/o molybdenum and 1 w/o copper in the 50 w/o nickel-25 w/o chromium base. Its corrosion rate of 22 mils per month in Niflex, with no selective attack, was significantly lower than the 105 mils per month recorded for Hastelloy F. Even lower rates would be expected under the less stringent conditions of actual process operation. Indications are that more resistance might be obtained by increasing the chromium and nickel contents.
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