Hot rolling

Hot rolling is referred to as the rolling process of a rolling material ( slab, stick, wire, etc. ) at a temperature above the recrystallization temperature of the metal to be processed. In the steel is usually 720-1260 ° C, with other metals are the temperature ranges at other orders of magnitude ( for example, aluminum 250 to 500 degrees Celsius).

The advantage of the hot rolling is that the rolled material is softer at higher temperatures and thus can be deformed with less force. For steel, the metal is also in place in the austenitic, ferritic state (i.e., the iron atoms are held face-centered cubic space centered cubic arranged ). In the austenitic region are of deformation (ie geometric relationships between the input and output variable) of up to 1:250 possible (example: typical slab thickness in a hot strip mill is 240 mm, final thicknesses are minimal 0.8 mm - cools at lower thicknesses, the band between the rolling operations to much on ). In flat steel are of deformation of up to 120 in a typical hot strip mill possible. For final thicknesses below 3 mm steel but is often cold-rolled (eg rollers in pure ferritic range of steel ). In cold rolling, are accessible without intermediate annealing, the maximum deformation of up to 1:10.

Equipment used for hot rolling are hot strip mills for sheet metal and wire mills and rod streets for round and square material and profiles. For the preparation of the necessary primary material (billets and roughed slabs ) block and slab rolling mills are used.

Of aluminum can be obtained depending on the alloy hot-rolled strip thickness of two to six millimeters, such as is the heat to be rapidly lost due to the large surface area. For further decreases in thickness, the sheet must be cold rolled.