The way to prevent defects in the process of pickling

A deep groove pickling line: deep groove pickling line is the typical characteristics of acid flow minimum, as a result has a high laminar boundary layer on the strip. Shallow trough pickling line b: only slowly in the shallow trough pickling line acid flow, resulting in strip laminar boundary layer has high above. However, under the strip pickling effect is better than the deep groove pickling line. But in front of the drying roller is more product set acid could lead to problems with sealing. C: turbulence pickling line in each of the pickling bath only on strip with only two turbulent area. However, in the export of the pickling bath need larger energy in seal. D Turboflo pickling line: in the steel strip, below each 2 meters a turbulent area. Acid back inside the tank cover, thus reducing the pickling tank outlet seal energy requirements. 1 pickling bubble is due to the acid pickling bubbles and bare metal, to generate hydrogen. Hydrogen metal and acid to produce chemical reaction, generate some of the hydrogen atom, it infiltrates into the crystal lattice of metal, and make it happen deformation, deformation after more to make hydrogen diffusion in metal, through the metal part of hydrogen atoms and molecules, and escape from the acid, part of the hydrogen molecules in crystal lattice deformation produced by the 'microscopic space' on the border, or of metal inclusions and the pore and hydrogen in the air pressure can reach hundreds of atmospheric pressure, the produced cause of hydrogen embrittlement in metals internal stress. Prevention measures: adjusting the concentration of the acid; Control the pickling solution and the temperature of strip steel surface flat state, etc. 2 a pickling metal remain in the acid solution for a long time, make its under the effect of acid solution, the surface gradually became rough pits. Pickling unit because of the continuous operation interruption, lose pickling continuity, or because of strip steel strip processing time is too long, etc. Prevention measures: as far as possible the operation of the whole unit to cooperate closely, ensure the production on the rails. After three owe pickling steel strip pickling surface residual local not washed out by the iron oxide called owe pickling. It is mainly due to the oxide thickness unevenness, thicker parts of tin oxide need longer pickling time, at the same time, the decomposition of FeO became more difficult to dissolve; Strip waves and rocker is bigger, in the process of pickling, undulation or bend the part by soaking in acid, cause leakage pickling; Pickling before mechanical breaker is not perfect, especially on both sides of the strip end of the tin is not broken, etc. Prevention measures: smooth advance good flatness, for iron sheet thicker, and the area of strip is small, can be adopted to local pickling time, then a pickling line method to rust. 4 corroded steel strip pickling surface residue after a little acid solution or strip not completely dry after cleaning the surface rust again. In addition of strip steel at high temperature after pickling cleaning water residence time is too long, also can produce corrosion phenomenon. Prevention measures: strictly enforce pickling, cleaning procedures, in a timely manner to the coating of oil, and should be piled in a dry place. 5 cut new appeared in the process of strip steel in the unit operation of cut, is because the take-up roll, bending roll surface quality hard foreign bodies, or strip of ribbon and fold the edges and guide into line contact, or flap strip steel in the process of split volume discount scraper, etc. , make the surface to draw new scars. Prevention measures: check the rolling of the unit components and guide, maintain good equipment.