What is the difference between hot rolling mill and cold rolling mill

In the hot rolling process, the slab is mainly made of continuous casting slab. After heating, the strip steel is made of cold rolling mill and hot rolling mill. Finally, the finished steel of the hot rolling mill is cooled to the temperature zone established by laminar flow. It is wound on the steel coil by the winding machine, and various finishing operations are carried out according to different needs. Users straighten the cross section of the leveling line The inspection and packaging turntable of longitudinal section is processed into flat steel roller and longitudinal cutting steel.
In short, the processed parts are heated, and the red and hot steel blocks burned on the equipment machine have been rolled for many times, and then cut and cut into a steel plate. The cold rolled steel coil is used as raw material. After stripping and removing the oxide scale, the cold rolling machine is used for cold treatment to roll the finished products into hard coils. The cold hardening caused by continuous cold deformation leads to the hardness, toughness index The increase and decrease of, so the stamping performance will deteriorate and can only be used for fragments with simple deformation. The cold-rolled hard roll can be used as the raw material of hot-dip galvanizing equipment because the hot-dip galvanizing unit has annealing line.
Generally, the weight of the roll is usually about 10 tons, and the steel coil is continuously wound to the normal temperature of the hot-rolled pickling roll. Because it is not annealed, its hardness is very high, and its machinability is very poor. It can only perform simple directional push ups less than 90 degrees. For simplicity, the cold rolling technology is processed and based on the hot-rolled coil, Considering the dynamic change of vibration displacement of cold rolling roll in the vertical direction, the dynamic model of rolling force is set.
According to the calculation formula of rolling force, the formula for calculating rolling force is derived from the decoupling of rolling force and rolling radius in flat state. On this basis, the influence of vibration of mechanical structure of cold rolling mill is further considered, and the equation of nonlinear vertical vibration system with dynamic rolling force is established. The main equation of system equilibrium frequency is solved by harmonic balance method, The actual parameters are simulated to analyze the nonlinear stiffness.