Meanwhile, several elements have to be conscientiously checked, as they can influence the process: - Cleaning degree of the semi-finished product: cladding results are directly influenced by the previous state of the wire, from the rod preparation (deoxidisation) down to the re-drawing (lubrication); - Descaling with H2SO4 solution is absolutely necessary if the semi-finished product is not clean. A minimum percentage of copper sulfate helps the cladding of the wire surface; - Copper bath: the quality of the coating is proportional to the type of bath and relevant conductivity.

The main parameter to be controlled is the concentration of copper and acid H2SO4. It must be kept constant. In addition, a high-concentration of H2SO4 is detrimental as it causes a too high-reaction speed and, consequently makes the cladding soft and with low-adhesion. The iron content is also important, especially for this kind of cladding where the dipping is particularly short (SAMP Sistemi suggests a constant value of 30g/l max). The bath temperature can affect the coating (the shorter the dipping duration, the higher the temperature must be), and must be carefully controlled. The temperature cannot exceed 60�C (45�C is the recommended optimum). Other parameter includes the dipping duration: - After dipping for 1 second at 45�C, the coating thickness should be 1.5 to 2.5g/m2 (copper); - After dipping for 1.5 seconds at 45�C, the coating thickness should reach 2 to 3g/m2.

The above data is given only as an indication and cannot be guaranteed as several variable elements must be taken into consideration. Furthermore, the quality of the finished wire depends on the cladding quality and not on the copper quality.

Photo: Wet drawing line for low, medium and high-tensile strength ferrous wires