| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for controlling an acid concentration of an acid solution including dissolved Fe components, which is used to finish a base metal to a desired surface when manufacturing a cold rolled steel sheet having a satisfactory polished finish characteristic from the base metal of a hot rolled steel sheet. SOLUTION: The method comprises acid cleaning a hot-rolled austenite stainless steel sheet, for a dipping time equals an initial dipping time, while Fe concentration is 0-10 g/l, when acid cleaning with an aqueous mixed solution of nitric acid of 20-100 g/l and hydrofluoric acid of 50-200 g/l after an annealing/ preliminary descaling process, and for a calculated time as a dipping time equals an initial dipping time×1+(Fe concentration -10)×0.1}, when Fe concentration exceeds 10 g/l; wherein the initial dipping time represents a dipping time in a condition that the acid is newly built, namely Fe content is zero.
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