| 摘要 |
PURPOSE:To efficiently remove oxide films consisting of Si and to improve production efficiency by subjecting a high tensile cold rolled steel plate to brush grinding, then to pickling with hydrochloric acid. CONSTITUTION:The high tensile cold rolled steel plate 1 which is continuously annealed in an inert gaseous atmosphere and contains >=0.2wt.% Si is subjected to the brush grinding of the oxide films 2 of the Si as a first stage, by which the oxide films of the Si are partly ground off to expose Fe layers. In succession, the steel plate is pickled with hydrochloric acid 3 as a second stage, by which the Fe layers at the boundaries of the oxide films and the Fe layers are dissolved from the exposed Fe layers although the oxide film 2 are hardly soluble in the hydrochloric acid 3. The oxide films 2 of the Si are efficiently peeled and removed from the Fe layers by progressing the pickling. As a result, the pickling efficiency is improved and the coatability and chemical conversion treatability are improved. |
