| 摘要 |
PURPOSE:To carry out the safe continuous pickling of stainless steel without generating harmful gases by using hydrochloric acid having a specified concn. at a specified bath temp. CONSTITUTION:Stainless steel is continuously pickled with hydrochloric acid having a concn. C (W/V%) at a bath temp. T( deg.C). The concn. and temp. are set so as to satisfy equations 65<=T<=90 and -1/4T+30<=C<=-1/4T+47.5. This treatment is applicable to any kind of stainless steel, and it is preferable to carry out conventional pretreatment. The pickling work is safe, and the generation of gaseous NOx is prevented. The finish of the stainless steel is further improved by carrying out pickling with nitric acid having about 5-15% concn. of HNO3 at about 50-70 deg.C bath temp. for about 20-120sec immersion time after finishing the pickling with hydrochloric acid. |
