It is mainly aimed at steel pipes, which are prone to corrosion reactions, and there is a certain hidden danger to equipment damage after corrosion. Removing all kinds of oil, rust, scale, welding spots, and other dirt can greatly improve the corrosion resistance of steel.
If there is dirt on the surface of the stainless steel pipe, it should be mechanically cleaned and then degreased. The presence of grease on the surface will affect the quality of pickling and passivation. For this reason, degreasing can not be omitted. You can use lye, emulsifiers, organic solvents, and steam.
Passivation is the last process step in chemical cleaning and is a key step. Its purpose is to prevent corrosion of the material. For example, after the boiler is pickled, washed with water, and rinsed, the metal surface is very clean, very activated, and easily subject to corrosion, so it must be passivated immediately to form a protective film on the cleaned metal surface to reduce corrosion.