With the annealing of steel, oxygen reacts with iron on the hot metal surface. Iron oxides, so-called scale, arise. This hass to be removed, for example in case of steel slabs or billets, through descaling. If the scale were to remain on the metal surface, it would be rolled into the steel in the subsequent rolling processes. This would have a significantly negative influence on the steel quality, so that certain parameters are not capable of being achieved, such as a predetermined strength with the finished product. The prices which a steelworks can achieve for its products on the international market are in line with the quality and purity of the steel so scale removal is imperative.
In case of longer annealing processes with higher temperatures, mixed oxides can also form from the alloying elements in the steel, as well as the iron oxides. This form of scale adheres far more strongly to the surface. Hydromechanical descaling by means of high-pressure water offers the possibility, by means of the adjustment of the pressure matched to the respective material, of guaranteeing optimal descaling. Generally there is a trend towards descaling with higher pressures up to 400 bar. This increased pressure allows a simultaneous reduction in the quantity of water used. Reduction in the quantity of water used reduces the cooling effect on the steel, and reduces the energy used to supply and filter the water. With KAMAT high-pressure pumps, this optimal descaling balance can be achieve. Water containing scale can be pumped easily by KAMAT pumps
KAMAT has established itself as a competent pump and valve manufacturer in many large rolling mills worldwide. For a large Indian rolling mill for example, a pump system was supplied with an installed overall capacity of 8,800 kW. In total it involved 16 pumps of the type K 55000, which were combined to eight stations of two 550 kW pumps each.