Purpose of Rinsing

After being pickled and taken out from the pickling tank, steel pipes have residual acid, iron salt particles, and other substances adhering to their surfaces. These substances are detrimental to hot-dip galvanizing, so the steel pipes must be immediately rinsed in flowing cold water or hot water. According to measurement data, when sulfuric acid solution is used for pickling, the iron salt content is 7 grams per square meter; when hydrochloric acid solution is used, the iron salt content is 2.3 grams per square meter. If rinsing is performed after pickling, the adhesion amount of iron salt on the surface of the steel pipe can be reduced to 0.5-1 gram per square meter. Of course, using hot water for rinsing is even better, as it can also remove some hydrogen from the steel pipe substrate. Thus, it can be seen that rinsing is an important step in improving the quality of hot-dip galvanized steel pipes.