Abstract
As it is said that the ultrasonic wave energy has excellent effect in pickling of steels, the ultrasonic pickling of mild steels was tested under the following conditions:
(1) Solutions: -3% and 5% hydrochloric acid solutions and 5% sulfuric acid solution.
(2) Pickling temperature: -22°C and 50°C.
(3) Applied ultrasonic waves: -resonant frequency 42kc/s±2kc/s, power 150W.
(1) When steels are pickled with the above mentioned acid solutions at room temperature, the emitting of ultrasonic waves accelerates the descaling speed remarkably. But with warm sulfuric acid solution the effect is not so remarkable.
(2) When ultrasonic waves are applied, the increase of descaling speed is accompanied by an increase of loss of materials and the effect of inhibitors is considerably poor.
(3) With ultrasonic pickling little or no hydrogen is generated, according to the conditions.
(4) The electrode potential of the steel exposed to ultrasonic waves is shifted to the noble side, and the steel does not seem to be polarized.
