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Continuous hot - galvanizing of strip steel adopts online continuous annealing(2)

- Jun 30, 2018 -

Continuous hot - galvanizing of strip steel adopts online continuous annealing

   The flat roller sticky zinc problem has always been a problem in high surface quality of galvanized products, need to be flat, the machine equipment to make the necessary improvements, also can add in flat desalting water cleaner. Nbsp6 post-treatment process includes passivation, prephosphating and oil coating. By passivation treatment, the surface structure and luster of galvanized layer can be improved, the corrosion resistance and service life of galvanized layer can be improved, and the binding force between coating and matrix metal can be improved. At present, the passivation treatment mainly USES chromium, acid salt passivation. Some activators, such as fluoride, phosphoric acid or sulfuric acid, are added to the passivation solution to obtain a thick chromate film after passivation. When fluoride is present in the passivation solution, the surface tension of the steel belt can be decreased, the film forming reaction can be accelerated, and chemical polishing can be increased to make the passivation film fine and bright. For building hot-dip galvanized steel plate, Japan NKK company developed with excellent corrosion resistance and! .A special chromate passivation coating resistant to black rust. For many years, scholars have studied nontoxic or low-toxic inorganic corrosion inhibitor as passivating agent. Molybdate is one of them. Its toxicity is lower than chromate, but the corrosion resistance after passivation is only equivalent to that of low Cr passivation. In nontoxic water-soluble acrylic resin (AC) to add a small amount of salt molybdate and phosphate (M) (ACM) is a kind of passivation solution, instead of toxic chromate passivation treatment, the results show that using hot dip galvanized layer, the nontoxic passivation passivation solution, can delay the galvanized layer of white rust and corrosion resistance of the level is close to chromate passivation.Although various chromium-free passivation technologies have been reported in the literature, no chromium-free passivation technology can completely replace the chromate-free stalking process. Some chromium-free caking processes are similar to chromate caking in some aspects, but their market prospects and applications are promisingThe scope of use and the environmental protection effect of users need further study. But there is no chromium passivation instead of chrome, before, there are fewer hot-dip galvanizing units with prephosphating capacity. And the adoption of A substitute for the traditional galvanized steel plate can not only extend the life of products, but also reduce the cost of materials. China's online prephosphating hot-dip galvanizing products improve the forming performance of hot-dip galvanizing products stamping parts, except for anti-rust oil, including weekly;Salt passivation has been a trend. Therefore, it can be predicted that the on-line phosphorus pretreatment technology of the unit needs further study. In addition, for the semi-solid anti-rust oil,