1. The influence of hydrochloric acid concentration and temperature
In hydrochloric acid solution, the pickling speed increases with the increase of acid concentration and temperature, but due to the volatility of hydrochloric acid, both acid concentration and temperature are limited.
2. The influence of FeCl2 in acid solution
The shortest pickling time is obtained when the FeCl2 content in the acid solution is optimal; The optimal FeCl2 content is about 4-8% lower than its saturation value in this state; When FeCl2 approaches saturation, the pickling time is the longest.
During the entire hydrochloric acid pickling process, although the hydrochloric acid content decreased, FeCl2 increased accordingly. These two influencing factors offset each other within a certain pickling time, so the pickling speed only changed slightly during this period.
The pickling speed should ensure that the strip steel reaches the predetermined time in the acid solution. If the speed is too fast and passes through the acid solution, insufficient pickling will occur.
The degree of mechanical phosphorus breaking is sufficient to accelerate the pickling speed.