Coated hot-rolling and cold-rolling

The Sendzimir treatment is a hot-dip galvanising process. Starting with a pickled material, i.e. one that has been stripped of oxide and scale, a galvanising process is then carried out in a molten zinc bath at 700°C. Obviously, this treatment isolates the steel from external corrosives and the amount of zinc on the surface can vary depending on the application in the order of microns (µ) per mm².

In rural areas, far from the coast, a loss of 1 µm/year is expected, which can increase to between 4 and 8 µm/year in areas with high humidity or coastal areas with high salinity.

Tests to calculate the tightness of the zinc are carried out in an extreme environment with salt spray, and give results in hours. The difference between these materials lies in their coating and therefore their resistance to oxidation:

• Sendzimir 🡪 approx. 250 hours

• Aluzinc 🡪 approx. 500 hours

• Magnelis 🡪 approx. 1000 hours

In general, these are steels on a galvanised base. In the case of pre-painted products, these undergo an additional paint bath treatment to improve their resistance to weathering.

The same procedure is carried out for plastic-coated steels: in this case, however, the steels will not be painted but given an adhesive plastic film, which is flexible, workable, and stable under the specific conditions of use. This treatment is especially suitable for outdoor applications to counteract wear and tear or abrasion, or when special resistance is required.