Important in the process of pickling process is introduced

1 straightening strip steel commonly used in pickling before straightening roller straightening machine. The role of the straightening machine is to make the strip steel produced by open coil and sheet metal crusher to the straightening of bending; Can to a certain extent, make the strip steel wavy and caused by uneven on both sides of the roll gap of strip steel to reduce the small wave form; So as to achieve elimination with steel department to run on the crew is produce of surface scratch, ensure the strip head to tail section shear straight, is helpful for welding and light the whole, guarantee the quality of cut edges and winding. 2 descaling descaling method can mainly divided into mechanical breaker method, chemical and mechanical descaling method -- Chemical combination method. Mechanical descaling method mainly include grinding wheel grinding, bending breaker and shot peening breaker three forms. In mechanical descaling effect of shot peening with scale efficiency is highest, lowest grinding wheel grinding. The bending breaker is usually used, bending breaker mainly by repeated bending steel strip descaling effect, this method can play a broken iron scale to improve the effect of pickling descaling, but cannot completely remove iron scales, so must work with pickling descaling together. 3 acid 3. 1 acid pickling effect mainly completely remove oxide coating on the surface of the material. Hot strip surface oxidation iron is usually of three layers: the outer layer of ferric oxide, middle ferroferric oxide, the inner layer of iron oxide. Strip surface oxide porous and cracking because of the nature of the combined with mechanical crushing and cause cracks, therefore, strip steel in acid solution, the surface of three layers of tin oxide over reacting with acid at the same time. 3. 2 the selection of pickling acid acid with sulfuric acid and hydrochloric acid commonly used in the acid solution. But more commonly in the actual production use hydrochloric acid as acid solution, because in terms of hydrochloric acid with sulfuric acid has the following advantages: a. Hydrochloric acid as acid medium, can quickly dissolve tin oxide, rarely erosion parent metal; b。 With hydrochloric acid as acid medium, pickling time is shorter; c。 By hydrochloric acid pickling of strip light appearance; d。 Hydrochloric acid easy to regeneration; e. Operation cost is low. 3. 3 the chemical substance in the hydrochloric acid as acid pickling solution, mainly occurs in the strip into the acid solution the following chemical reaction: 3. 4 heating acid solution of the acid solution concentration and temperature change on the acid pickling speed and quality has a direct impact. Increase the concentration of acid in the production and raising temperature can make the pickling effect is significantly improved, but from the consideration on the actual production cost and efficiency, raise the temperature more economic than increase the concentration of acid solution. In the actual production of acid solution there are two ways: one for direct steam heating, another for indirect heating graphite heat exchangers. Because of the direct steam heating can make steam condensation water dilute acid soluble liquid concentration and bad for pickling, enable a large increase waste acid at the same time, the increase of acid recovery unit load. So generally choose indirect heating graphite heat exchangers.