| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high purity Fe-Cr alloy the C content of which is reduced to <=0.003% by decarburizing annealing by controlling the dew point Dp of the atmosphere and heat treating temperature T. SOLUTION: When subjecting an Fe-Cr alloy sheet containing >=0.03 mass % C to decarburizing annealing in a hydrogen atmosphere or in a hydrogen- nitrogen atmosphere, heat treating temperature T( deg.C) is held within the range of 700 to 1,200 deg.C, and the following inequality is satisfied between the dew point Dp( deg.C) of the atmosphere and the heat treating temperature T to reduce the C content to <=0.003 mass %: 0.0625T-86.9>Dp>-0.04T-46. In this way, the formation of an oxidized film checking decarburizing reaction is suppressed, and the diffusing and oxidizing reaction of C in the steel is promoted, thus, decarburizing can be performed to a level of extra-low carbon of <=0.003%.
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