The pickling principle of iron straps

The pickling principle of iron straps. Iron straps material is hot rolled steel band, after hot rolling steel strip surface will have a hard and brittle layer of tin oxide, tin oxide this layer is generated during hot rolling. Besides iron oxide in the tin oxide, P, Mn, Si, S, C and other elements, the oxide harmful to cold rolling, if these with tin oxide for rolling steel strip directly to cold rolling mill, can cause the following effects: in the case of with great rolling, tin oxide will be pressed into the matrix of the strip, affect the cold rolled steel surface quality and processing performance, even cause waste. And tin oxide and broken after entering the cold-rolling emulsion system, on the one hand, pollution of the emulsion, shorten the service life of the emulsion, on the other hand the damage on the surface of the roll and adversely affect the quality of the surface of cold rolled steel belt. Countries around the world to remove iron oxide on the surface of the hot rolled steel belt have taken different approaches, including mechanical method, chemical method and electrochemical method. Chemical method is the most commonly used method, that is, use the strong acid such as sulfuric acid, hydrochloric acid, nitric acid, hydrofluoric acid and iron phosphate on the surface of the steel materials react and get rid of iron oxide, nitric acid and hydrofluoric acid is mainly used for pickling of stainless steel. Because the hydrochloric acid has pickling speed ( The pickling speed is about more than twice as likely to sulfuric acid pickling speed) , no corrosion of steel matrix ( Rare hydrogen embrittlement phenomenon) , can be completely recycled and other characteristics, widely used in steel pickling line.