Brief introduction of pickling operation of packaging steel strip

Brief introduction of pickling operation of packaging steel strip
　　Hot rolled coils are cold rolled billets. Because the final rolling temperature of the hot-rolled coils is about 800°C or more, iron scale is formed on the surface. One of the purposes of cold-rolled strip steel is to obtain good surface properties. Therefore, the iron oxide scale must be removed before cold rolling. This is the first purpose of the pickling operation. The tasks completed by the pickling can be summarized as follows:
　　 1. Remove surface oxide scale
　　 There are physical (mechanical) methods and chemical methods to remove surface oxide scale. For the treatment of cold-rolled billets, chemical methods that can increase surface properties are generally used, that is, pickling is used. The most used acids are hydrochloric acid and sulfuric acid. Recently, most of the hydrochloric acid lines are used. It has a short processing time and good quality. There are also chemical methods, supplemented by physical methods, and the two methods are used together.
　　2, the coil is enlarged
　　 In order to increase the operation rate, increase the yield rate, and more effectively use the storage space of the factory in the next process, 2-3 hot-rolled coils are welded together to enlarge the cold-rolled coils. An example of its effect is shown. The welding machine generally adopts the flash butt welding machine with short operating time and strong welding part.
　　3. Oiling
　　The purpose of oiling is to prevent rust, to prevent scratches and to provide auxiliary lubrication during rolling, and to pre-coat a layer of oil on the pickled steel strip.
　　4. Disc type edge trimming machine (edge u200bu200btrimming)
　　 Cut the strip width according to the order. And in order to avoid rolling accidents caused by the variation of the width of the hot-rolled coils, trimming is performed.
　　5. Management of properties of hot-rolled coils
　　 The inspection of the properties of hot-rolled coils (surface defects, plate shape, coil shape, etc.) is to improve the quality of raw materials and improve the quality of finished products.
　　The pickling line is located between the hot rolling process and the cold rolling process. In terms of mutual quality management, it can be said that it is a very important line.