The process for the production of hot-dip galvanized strip directly follows the cold-rolling. This process combines in one line the cleaning, annealing, galvanizing (galvannealing), temperrolling and surface treatment.

In order to keep production continuous, the strip, which has been welded to ensure continuous production, goes through such cleaning procedures as alkaline cleaning, brush cleaning and electrolytic cleaning to get rid of the emulsion residue and iron abrasion left on the surface during the cold-rolling, before it finally enters the furnace with a defined surface cleanness.

In the furnace the strip undergoes a continuous annealing process, where it is recrystallized in a controlled atmosphere between 700 and 850℃ depending on the steel grade. Here the strip obtains the desired mechanical properties.

Still in a controlled atmosphere, the strip is cooled down in the subsequent heat equalizing and rapid cooling section of the furnace to a temperature of about 20℃ above the bath temperature of the molten zinc of 450℃. The strip only exits the controlled protection atmosphere after the zinc bath.

The thickness of the zinc layer is controlled by an air knife with compressed air or nitrogen. The closed-loop control is achieved by adjusting the set values and actual measured values of the zinc layer, which makes it possible to adjust to specific requirements for identical thickness or differential thickness of coated layers on both sides. After galvanizing, the galvannealing furnace can be used alternatively with the aim of heating the strip by means of high-frequency inductors. In this process, iron atoms diffuse out of the base material into the zinc layer, which will thus be transformed into an alloy of zinc-iron layer. After the galvannealing procedure, the surface of the zinc-iron layer with a Fe percentage of 8-11% appears uniformly light grey.

The roughness and flatness degree of the finished galvanized strips are achieved by skin pass mill and tension leveller.

Before being packaged for shipping, a series of alternative treatments can be carried out, such as chemical passivating, oiling, chromating, phosphating, and anti-fingerprint treatment, so as to protect it against temporary corrosion and friction oxidization as well as to meet customers' requirements for further processing.

All surface treatment, especially chemical passivation and sealing, is CrVI-free to comply with EU legislation.