ECONOMIC SECONDARY DESCALING

This process for the secondary descaling of running metal strips, especially made of steel, during the hot-rolling thereof, by spraying water onto the surface thereof using spray rails having nozzles supplied with pressurized water, is characterized in that the nozzles are supplied at low hydraulic pressure, not exceeding 30 bar (preferably below 10 bar, but without going below 4 bar), and in that for the purpose of providing a thermal effect of the water sprayed onto the surface to be descaled quantitatively similar to the thermal effect obtained with the usual known method of secondary descaling at high pressure, namely a cooling of the strip which reduces its surface temperature to approximately 600° C., so that the heat flux density extracted from the strip (HF) resulting from the cooling of its surface by the sprayed water is similar to that achieved with said known high-pressure practice. The invention applies to any secondary descaling, both upstream of the finisher and upstream of the rougher of a rolling mill train. It provides an immediately operational response to the reduction of the descaling costs, that is to say it is compatible with rearranging existing industrial equipment, therefore without necessarily involving the reinstallation of complete new equipment.