Wire rod pickling and phosphating lines

The purpose of the steel phosphating process is to produce a surface conversion layer of thin and compact thickness and strongly anchored to the surface in order to facilitate cold forming or further drawing operations on the material. Among the different types of phosphate, the most frequently used for wire rods is zinc phosphate. After phosphating, a lubricating layer is applied to the surface.

To ensure a successful process, the surface must be perfectly clean of oil, grease, metallic oxides, or acids. This can be achieved through chemical pickling operations (with H2SO4 or HCl) and subsequent strong water washing or shot-blasting. Generally speaking, the phosphating process involves dipping the material into a hot tank, with dipping time based on the desired layer thickness.

However, the phosphating process is not applicable for stainless steel material, in which case it is replaced by a salt coating operation. As an alternative, Sirio Wire suggests using a new technology based on special polymers that can be applied at temperatures about 40 °C to prepare surfaces for cold forming.

With Sirio Wire equipment, coils are usually handled by special bridge cranes equipped with rigid slideways to avoid oscillations. The bridge crane can move on 2 or 3 axes, depending on the customer's requirements.

The tanks are equipped with suction hoods on each of their edges and tilting automatic semi-covers. In addition, the bridge crane is equipped with a suction hood and a scrubbing system to guarantee the complete filtration and neutralization of harmful gas and vapors (as per A.C.G.I.H. recommendations).

Sirio Wire lines also feature an innovative high-pressure rinsing device, which is especially important for rinsing high-carbon steel wire after pickling. More specifically, a special trident device with nozzles, which rotates around the coil, ensures complete cleaning (both inside and outside) of the pickled material, with the removal of carbon residue (smut) formed during pickling.

The company lines can also be provided with a dynamic pickling system, which consists in a vertical turbine that is positioned on the outside tank head. This device produces vigorous and effective solution recycling, homogenizes the bath solutions, and accelerates the surface reactions of the reagents on the metal surface, thus leading to reduced treatment times (up to 50%). Overall, the dynamic pickling device increases the efficiency of the process, allowing you to use a lower concentration of the reagents.