After solution annealing, the stainless steel welded pipe needs to be pickled to remove the oxide scale on the surface. The editor reminds you that the pickling of the stainless steel welded pipe should be done in moderation, and it should not be excessively pickled in order to pursue the brightness of the stainless steel welded pipe surface.

Because the pickling solution can make the stainless steel welded pipe get a white pickled smooth surface within the appropriate passivation time, but if the stainless steel welded pipe is soaked in the pickling solution for too long, frost‑like and cloudy erosion will occur in more than two hours., even severe pitting.

Moreover, excessive pickling can also lead to substandard chemical composition of welded pipes. From the electrochemical theory, a reasonable pickling passivation is a process in which the anode plate dissolves rapidly to produce a passivation film on the surface and converts it into a passive state of the anode plate. If the pickling continues, due to the decrease in acidity of the pickling solution and the increase in the concentration of iron ions, the passive anode may activate the anode in the local area, that is, excessive passivation or trans‑passivation.

In addition, care should be taken to avoid oil stains on the welded pipe before pickling. In the case of oil stains, the oil stains should be cleaned first and then pickled.

The pickling solution in use also needs to be kept clean, and the impurities and dirt at the bottom need to be cleaned regularly, and acid solution should be added in time to prevent the concentration of metal salts from being too high.