Alkaline cleaning and degreasing is an important treatment procedure before reduction and annealing in continuous hot dip plating of American steel strip.The work is to basically remove the oil and iron powder on the surface of the steel belt through the steps of alkali spraying or soaking, alkali washing, electrolytic alkali washing, water washing and water spraying.
When the strip is rolled on a cold mill, the surface of the strip will inevitably be covered with oil and iron powder.Oil pollution is mainly rolling oil in rolling emulsion.Iron powder is under the action of a large rolling pressure lead to the friction (especially in the deformation of the strip, slip zone before and after the slip zone, the coefficient of friction is greater than the rolling friction), from the surface of steel strip and roll surface friction.Because the material of steel belt and roll is different, their wear resistance is different greatly. The iron powder is mostly rubbed off from the surface of steel belt, while the iron powder rubbed off from the surface of roll only accounts for a small part.The oil, iron powder on the board is the object to be removed in the degreasing section.
So, how does degreasing work?a
1. Classification and properties of rolling oil
In order to find out the degreasing principle the classification and properties of rolling oil should be clarified first.Rolling oil can be divided into three types.
One is saponifiable oil.Animal and vegetable oils, such as pork, beef and palm oil, are saponifiable.The property of saponifiable oil is that it can be saponified and emulsified.
Second, non-saponifiable oil.All mineral oils are non-saponifiable.The nature of non-saponifiable oil is that it can not occur saponification, can only occur. Emulsification.
Saponifying oil, mainly by emulsifying removal, there are certain. Third, some synthetic lipids.Its properties lie between saponifiable oil and chemical property.