Thermal effects of a high-pressure spray descaling process

Abstract

The article deals with the possibilities to remove scale from a slab surface by means of a hydraulic spray using pressurized water as well as with an analysis of the influence of the employed removal method on the thermal field of flat rolled products. The effect of spray descaling on the temperature field of the rolled material was established experimentally in a real mill in semi-operational conditions during the process of secondary spray descaling. The experiment was carried out with two sample slabs. The dimensions of a slab were 400 mm × 400 mm × 30 mm and the chemical composition was 0.20 % C, max. 1.4 % Mn, 0.045 % P, 0.045 % S and 0.009 % N. The temperature data for different depths below the surface of the slab being sprayed, obtained during the experiment, were processed using IHCP1D, a software developed on the basis of the Beck minimization-principle algorithm. The obtained values of the heat transfer coefficient represent the boundary condition for a numerical model of the spraying process. Its mean value established in the experiment was 18460 W/(m2 K).