1) An operating unit that removes iron oxide from a hot rolled product by immersion into a hydrochloric (#3/#5 Picklers) or sulfuric acid solution. 2) The pickler tank contains 5-6% concentrations of sulfuric acid. This solution is kept at a temperature of 180-190 degrees. The purpose of the pickler is to complete the preparation of the steel for p... Found on https://steelforge.com/literature/steelog-the-5000-word-metals-glossary/