Pickling is used to remove surface oxides (scale) from the steel during the hot rolling production process.
This operation is carried out by passing the steel through tanks of hydrochloric acid, which have very specific concentrations and temperatures, followed by appropriate rinsing.
This processing is necessary to guarantee the quality of the coils, which will subsequently be cold rolled and processed directly on the galvanizing lines.
During this phase, we also create the desired width of the strip by trimming its edges using a flattening machine, giving it the thickness required for subsequent steps.
The obtainable thicknesses of the pickling line range from 1.5 to 4 mm and the widths from 550 to 1300 mm.
Cold Rolling Mill
This phase, carried out continuously in a Tandem rolling mill, allows the thickness of the pickled coils to be reduced by the combined action of loads and pulls exerted by four four-cylinder rolling stands.
During this reduction in thickness the speed of the coil strip increases progressively between the various stands to reduce the potential for deformation.
The thicknesses obtainable vary from 0.23 to 2 mm and maximum width of 1290 mm. In addition to the thickness, the rolling mill also gives the outgoing coil good flatness characteristics.
Continuous hot-dip galvanizing, using the Sendzmir process, is carried out by immersion of the coil strip in a tank containing molten zinc with small additions of aluminum to improve the adhesion and flexibility of the finished product.
The addition of zinc gives the steel substrate a cathodic protection against corrosion, increasing its durability over time.
A subsequent skin-pass process allows us to further level the surface and giving it a roughness which makes it suitable for painting.
Before entering the galvanizing tank, the coil strip passes through ovens which perform the double function of cleaning and providing the heat treatment for the annealing process required to give the steel the required mechanical characteristics necessary for further processing.
The thicknesses obtainable vary from 0.25 to 3 mm with widths up to 1600 mm.
Painting line uses the coil-coating process. It is divided into various phases: surface degreasing; chemical pre-treatment; the wet application of the first coat of paint (primer) and firing in the oven; the consequent application of the finishing coat (top coat) followed by the second firing to reach the final winding of the coil.
Strict laboratory controls manage the production process and test the quality of customers’ final products.