Production process of cold-rolled steel strip for packaging steel strip

Production process of cold-rolled steel strip for packaging steel strip
　　The most general soil art process for cold-rolled strip production; centered on the strip cold rolling mill, from hot-rolled coils to continuous pickling, cold rolling (strip cold rolling mill), electrolytic cleaning, annealing, and leveling Rolling and finishing (shearing line, recoiling line) and other operations.
　　1. Continuous pickling
　　Continuous pickling is a process in which hot-rolled coils are continuously passed through a hydrochloric acid tip or a sulfuric acid tank to remove the scale on the surface. In addition, in order to improve the operation rate and yield of the subsequent process, several hot-rolled sheet coils are welded together and rolled into a large coil.
　　2. Cold rolled
　　The cold rolling mill is an equipment that milks hot-rolled coils to the thickness of the finished product at room temperature. Rolling oil is used as a lubricant between the roll and the strip, and as a coolant for the roll. Usually four-high multi-stand continuous cold rolling (tandem mill) and single-stand reversing mill are used for cold rolling. The former is used for high-efficiency and high-yield varieties; the latter has low productivity and is suitable for multiple varieties and special materials.
　　3. Electrolytic cleaning
　　Electrolytic cleaning is a process to remove the rolling oil remaining on the surface of the cold-rolled steel sheet. In the process of the strip continuously passing through the electrolytic cell, the electrolytic cleaning is used for degreasing.
　　4. Annealing
　　Because the crystalline structure after cold rolling has high hardness and poor workability, it must be recrystallized through annealing process to improve its crystalline structure. Annealing is one of the processes that greatly affects the performance of cold-rolled strip steel, according to the specifications of the finished product , Use, determine the annealing method (tight coil, loose coil), annealing system (annealing temperature, annealing time, heating rate, etc.).
　　5. Smooth rolling
　　 Slightly cold rolling the annealed steel strip to eliminate the yield platform while improving the flatness of the finished product and controlling the surface gloss. These are the purpose of flattening. The leveling mill adopts 1-2 four-high rolling mills, and the reduction rate is usually about 1%.
　　6. Finishing
　　In the shearing line or recoiling line of the last process of cold rolling, trimming, cutting, sub-coiling, etc. are performed to obtain the required product size, and at the same time, the size, surface, and shape of the product are inspected After the inspection, apply anti-rust grease to become the finished product.
　　 In Figure 5-2, it shows a typical layout of a cold rolling mill.