| 摘要 |
PURPOSE:To provide the subject process wherein the injection direction of an acid solution with respect to the advancing direction of a steel belt passing in lateral direction is set in the reverse direction at the upper surface of the steel plate and set in the same direction at the lower surface thereof. CONSTITUTION:In a case where, for example, a SUS 304 heat drawn steel strip 1 is subjected to spray pickling by nitric acid, the injection angle theta of a nozzle 3 is selected to be -5 deg. to -15 deg. at the upper surface of a steel belt 1, and the injected acid solution is caused to flow reversely the advancing direction 14 of the steel belt 1. At the lower surface of the steel belt 1 the injection angle theta' of the nozzle 5 is seleced to be +5 deg. to +30 deg., and the acid solution flows in the same direction as the advancing direction 14 of the steel belt 1. As described above, when the acid solution is injected, the acid solution flows on the steel belt 1 at the upper surface thereof while being stirred, the deteriorated solution is immediately replaced by a new solution. When the injection angle of the acid solution is selected in the positive direction at the lower surface of the steel belt 1, the acid solution is suitably developed in the advancing direction of the steel belt 1 and in a direction reverse to the advancing direction, whereby the pickling efficiency is improved. |
