| 摘要 |
The present invention provides an alloy-saving type of high purity ferritic stainless steel excellent in corrosion resistance and a method of production of the same. A high purity ferritic stainless steel excellent in corrosion resistance comprised of, by mass%, C: 0.001 to 0.02%, Si: 0.01 to 0.6%, Mn: 0.01 to 0.6%, P: 0.005 to 0.04%, S: 0.0001 to 0.01%, Cr: 13 to 22%, N: 0.001 to 0.02%, Al: 0.005 to 0.05%, Sn: 0.001 to 1%, and a balance of Fe and unavoidable impurities, said steel characterized by satisfying the two relations of the following formula (1) and formula (2) where I(Fe), I(Cr), I(Sn), and I(O) are the X-ray intensities of the Fe oxides, Cr oxides, Sn oxides, and other detected oxides at the steel surface measured by an X-ray photoelectron spectrometer: 0 < I Fe / I Cr < 5 and 0 < I O / I Sn < 3 To improve the effect of modification of the coating by addition of Sn, the method comprises annealing at a temperature higher than 800°C for final annealing, then cooling this by a cooling rate of 10°C/sec or more down to 700°C or less, holding this in a 200 to 700°C temperature range for at least 1 minute for cooling, then pickling in an aqueous solution containing, by wt%, at least 5% nitric acid or performing bright annealing while making a dew point of the atmospheric gas -50°C to -20°C. |
