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PRODUCTION CYCLE

tecnologia
The company produces hot-rolled steel plate from slabs of varying grades (obtained from continuous casting or ingots). The slabs arrive on site by truck or train and are temporarily stored in the external slab yard where they are catalogued, graded and numbered before being transferred inside the plant. All material is moved around the plant in complete safety by means of a 44-ton slab carrier and a 40-ton magnet bridge crane.

The slabs are flame-cut to the required dimensions and are then loaded into the reheating furnace where they are heated to the correct rolling temperature of about 1200°C. In this type of pusher furnace, in which both the top and bottom faces of the material are heated, the stock is fed into the furnace and pushes the preceding piece forward through the furnace. In this way, as one cold work-piece is pushed into the furnace, another, ready for rolling, is discharged.

When the rolling temperature has been reached, the stock exits via a slide, is halted and transferred  by the extractor arms to the roller table. Before rolling, the stock is sent to the descaling unit where extremely high-pressure jets of water (at 180 bar) blast away the scale (oxidized iron that forms on the surface of the slab in the furnace). The work-piece is now clean and ready for rolling.

Rolling consists of progressively reducing the thickness of the steel in a reversible two-roll roughing mill and/or in a reversible 4-high mill, according to a pre-established rolling schedule. The resulting plate is moving onto the hot leveller before the ends are cropped in accordance with the customer's requirements (for thicknesses below 50mm).
 
After levelling and cropping, the plates are moved to two cooling beds . When sufficiently cool, the plates are transferred by means of magnets suspended from a bridge crane to the Quality Control area where, in accordance with the relevant standards, they undergo a visual inspection, where flatness and dimensions are checked and ultrasonic testing is performed.
 
Plates with a thickness above 50mm are flame cut. Upon request, plates up to a maximum thickness of 30mm can be edge trimmed by plasma cutting, while those from 30mm to 220mm require flame cutting. Another option, again upon request, is the further cleaning of both surfaces of the plate by shot blasting. Rust and mill scale are removed, leaving a roughened plate surface ready for primering.