| 摘要 |
PURPOSE:To perform the work of safely acid pickling the titled steel strip without environmental contamination, by descaling said steel strip with an aqueous sulfuric acid solution under a specified condition, and then removing stains with an aqueous nitric acid solution under a different condition while passivating it at the same time. CONSTITUTION:In removing oxide scale from a hot-rolled Cr stainless steel strip with an aqueous sulfuric acid solution, the acid pickling is performed in a manner such that the conditions of C1<=10, C1+0.8T1>=76 and T1>=55 (wherein C1 is the wt% of H2SO4 by 100ml of the aqueous sulfuric acid solution, and T1 is the temp. deg.C of the aqueous sulfuric acid solution) are satisfied. Thereafter, the removal of stains from the surface of the steel strip and passivation are performed in such an aqueous nitric acid solution that satisfies the conditions of -1/6T2+50/3<=C2<=-1/6T2+110/3 and 40<=T2<=80 (wherein C2 is the wt% of HNO3 by 100ml of the aqueous nitric acid solutions, and T2 is the temp. deg.C of the aqueous nitric acid solution). Hereon, the time of dipping said steel strip in each of the aqueous sulfuric and nitric acid solutions is limited within about 120sec. |
