Difference between overpickling and underpickling of stainless steel press fittings


We have to clean the stainless steel clamping pipe fittings after a long time of use. Over pickling and under pickling are often used in the cleaning process. What is the difference between the two in the cleaning process. Now stainless steel press fittings manufacturer can tell you.

1. Overpickling

Overpickling steel pipe, the surface of the spot corrosion, the emergence of a deep pit, serious make steel pipe into waste. Over-pickling is caused by the concentration of sulfuric acid solution is too low, the temperature is too high, the pickling time is too long, the sulfuric acid solution is not clean, part of the surface of the steel pipe is covered with a layer of dirt, not covered with the possibility of causing over-pickling. In order to prevent the occurrence of over-pickling, it is necessary to strictly abide by the technical operation rules of sulfuric acid pickling and add appropriate amount of pickling corrosion inhibitor. Hyperpickling defects, which are often irretrievable, should be avoided.

2. Underpickling

Underpickling refers to the fact that the iron oxide on the surface of the steel pipe is not completely removed after pickling. Underpickling is due to sulfuric acid solution concentration and temperature is too low, pickling time is too short, sulfuric acid solution dirty, steel pipe surface oil, sulfuric acid solution concentration is not uniform, solution and metal iron, iron oxide caused by local chemical reaction. Underpickling defects can be remedied and should be re-pickled as the case may be. However, the concentration and temperature of sulfuric acid solution should be appropriate, so that the pickling time is shorter, so as not to cause excessive pickling.

Difference between overpickling and underpickling of stainless steel press fittings

The above is to introduce to you the two methods of over pickling and under pickling of stainless steel press fittings. During use, the cleaning method should also be selected according to the key material, service life and composition of stains, so that the pipe fittings after cleaning will be bright and durable.