The rolling consists in billet compressing between the rotating rolls. The billet retracts between the rollers by friction forces, and the pressure forces reduce the transverse billet dimensions. The pressure forces are normal to the rolls surface.
There are three main types of rolling: longitudinal, transverse and cross- helical.
- The longitudinal rolling. The billet deformed between two rolls rotating in different directions, and moves perpendicular to the rolls axes. The flat billet produces this way.
- The transverse rolling. The rolls rotate in the same direction and impart the billet rotation. The billet moving along to the rolls axis and deforms. In this rolling way obtains the billet in the form of revolution body.
- The cross-helical rolling. The rolls located at an angle and report to the billet the rotational and translational motion during it deformation. In this rolling way obtains the billet with complex shapes.
The rolling profiles range divided into 4 main groups: long products, sheets, pipes and special types of rolled metal.
Long products profiles divided into simple shapes and complex shapes. Simple shapes are square, circle, hexahedron and rectangle. Complex shapes are channels, I-beams, rails, corners.
Steel pipes (tubes) divided mainly into seamless (Ф 30-650) mm and welded (Ф10 — 1420 mm.)
As special types of rolled metal can be specified the wheels, the ring, the cog wheels, etc.
Smooth rolling rolls use for rolling sheets and tapes. Rolling rolls with notches use for the shaped profile details production. There are hot rolling (with billet heating) and cold rolling.
A complex of equipment for rolling calls the rolling mill.
Rolling mills classify by the nature of the rolling process and products. There are blooming mills, slabbing mills, sheet mills, wire mills, profile mills, pipe-rolling mills and special mills.
The large square blanks (blooms) produce on blooming mills. Long products with sections of a square form, a circle form, a rectangle form, a triangle form, a segment form, a rhombus form, a corner form, a channel, a brand form, an I-beam form, etc. obtain from blooms on rolling mills.
Large rectangular blanks (slabs) rolled on slabbing mills. Smaller rectangular blanks and sheets produce from slabs on sheet mills.
Wire mills designed to produce a 5-10 mm wire.
Seamless and welded tubes produce on pipe-rolling mills.
The most diverse billets like railway wheels, car axles and grinding balls produce on special mills.
Rolling production has great importance in the country economy. Rolling is subjected about 90% all the smelted steel and most non-ferrous metals.