Among the areas covered by Ingeteam is the market niche related with Cold Rolling Mills, for carbon and stainless steel.
Cold Rolling is a continuous high speed deformation process, keeping the temperature below the crystallization point. The change in volume occurs in the direction of rolling (with hardly any deformation in the transverse direction), with the strip below its recrystallization temperature, at room temperature, increasing the strength by means of hardening the material, improving also the strip finishing and tolerances.
In case of carbon steels, cold rolling starts from hot-rolled and pickled coils, for thicknesses varying according to the type of steel, reducing its original thickness in percentages ranging from 30% for thick thicknesses and 90% for tinplate. This reduction can be obtained in cold rolling mills, which can be continuous, the so-called tandem (composed by up to 5 or 6 different stands), or reversible ones, in which the final thickness is reached in successive passes.
Cold-rolled carbon steel, produced as coils or sheets, is typically used for agricultural tools, automotive, containers, electric motors, home appliances, household electricity and metalwork
The material produced after cold rolling can be sold as:
- Full hard: Cold rolled steel, without annealing and with a low ductility. It requires for use a later stage of annealing or galvanizing.
- Annealing: Cold rolled steel, subject to a thermal process in which it recovers its ductility, allowing us to cold forming or cold drawing.
- Black Coil (Black Plate): Annealed material that serves as a base material for tinned and chrome plated.
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In case of stainless steel, the process is more complex, with previous stages passing through a previous heat treatment of the coils, in bell furnaces, after the hot rolling process, reaching cold rolling mills with input thicknesses between 2.5 and 8.5 mm to be later cold rolled with target thicknesses between 0.25 and 6 mm.
The cold rolling mill responsible for the stainless steel differs from the carbon steels being called cluster mill (20 high) or sendzimir (12 high), in single stand configuration, being constituted by monolithic stands, compact, multi-rolls, for material with a hardening level bigger than carbon steels.
These single stands can perform reversible reduction processes that reach 80% in successive passes. The work cylinders - two - are of very small diameter and very easy and fast change.