A rolling mill as a device for processing metals and other materials by the pressure of several rotating rolls was first mentioned in the works of Leonardo da Vinci. The oldest mechanism, described by the great master in 1495, was intended for tin processing. Rolling devices were already widely used in the 17th century, where they worked on the basis of manual drives, which were later replaced by water (water wheel), and then by steam. Today, hand-driven rolling equipment is often used for handicrafts.
The rolling mill as part of its equipment has a main part (a working stand, in which from two to several rolls can be located, electric motors and devices that transfer energy to the rolls from the engines) and auxiliary (equipment for moving workpieces, cutting, straightening, turning, etc. .). The design of specific equipment is tied to the type of product that is produced on it.
Rolled products depending on the type of cross section is divided into several groups, including:
- pipes (seamless or welded);
- sheet metal (thin sheets or plate (over 4 mm));
- long products (shaped or simple);
- special hire (angular, C-shaped, with a changing profile, etc.).
A rolling mill by type of product can be assigned to one of the following groups: pipe, tape, hard-rolled, special, sheet, wire, strip, broadband, high-quality, crimp (mainly blooming), blank, rail and beam mills. Equipment of this kind is bulky. For example, a camp considered to be small can have a length of fifteen meters, and the largest instance to date is 5500 meters long (owned by Anshen Iron And Steel Group).
The classification of rolling mills by design features is as follows:
- single-cage (they include a crate, supplemented, for example, by six electric motors, five couplings, four gearboxes, three gear stands and two spindles);
- linear mills (stands are located one after another, sometimes in several lines, products are processed in one direction);
- sequential (several single-stand mills are arranged sequentially or in a different order);
- continuous (the workpiece is processed simultaneously in a number of stands);
- semi-continuous (there are continuous sections and linear components of the equipment).
How does a rolling mill work? First, the metal ingot is heated in special wells (at a temperature of about 1800 ° C), after which the electric car feeds it for primary processing (for slabbing or blooming), where bars are obtained from the ingot. Then, on other equipment of rolling type, metal sheets or finished products of a given shape, such as rails, etc. are obtained. Modern equipment, as a rule, is casting and rolling mills that can process workpieces in cages at a speed of about 300 km per hour.
The manufacture of rolling mills is a complex and expensive process, however, today in Russia there are enterprises that produce such products. In addition to the main and auxiliary equipment for the successful operation of the complex, high-precision automation, lubrication equipment, as well as the provision of electric power mills with a total capacity of up to 200-300 megawatts are required.