Today we will talk about the technical points of rolling hard coil products!
In fact, hot-rolled steel coils are used as raw materials, and after acid washing to remove oxide scales, cold continuous rolling is carried out. The finished product is rolled hard coils. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the rolled hard coils increase, and the toughness and plasticity index decrease. Therefore, the stamping performance will deteriorate, and can only be used for parts with simple deformation.
Rolling hard coils can be used as raw materials for hot-dip galvanizing plants, as hot-dip galvanizing units are equipped with annealing lines. The weight of the rolled hard coil is generally between 20 and 40 tons, and the steel coil is continuously rolled on the hot-rolled pickling coil at room temperature.
Because it has not undergone annealing treatment, its hardness is very high (HRB greater than 90), and its mechanical processing performance is extremely poor. It can only be subjected to simple directional bending processing of less than 90 degrees (perpendicular to the coiling direction).
Generally speaking, cold rolling is the process of processing and rolling on the basis of hot rolled plates and coils. Generally speaking, it involves processes such as hot rolling, acid washing, phosphating, saponification, and cold rolling.
Cold rolling is made by processing hot rolled plates at room temperature, although rolling can also cause the steel plate to heat up during the processing, it is still called cold rolling. Due to the continuous cold deformation of hot rolling, the mechanical properties of cold rolling are relatively poor and the hardness is too high. It is necessary to undergo annealing to restore its mechanical properties, and those without annealing are called rolled hard coils. Rolling hard rolls is generally used to make products that do not require bending or stretching. For thicknesses below 1.0, rolling hard rolls can be used to bend both or all four sides with good luck.