KAWULOK Petr VSB - Technical University of Ostrava

Spoluautoři CZERNEK Stanislav, SCHINDLER Ivo, KAWULOK Rostislav, RUSZ Stanislav, SOLOWSKI Zdeněk, ČMIEL Karel Milan

At formation of pass rolls at section rolling mills the ability to predict with sufficient precision the ratio of elongation and spreading of material at its reduction plays a very important role. Perfect filling of the profile gauge depends on it, and thus also resulting dimensional accuracy of cross section of the final rolled product. The objective of the works was to determine, how the spreading is influenced by chemical composition of steel at otherwise constant conditions of rolling. The research was realised by rolling of prismatic samples on the laboratory rolling mill K350, namely on plain rolls at two temperature levels. At first it was necessary to optimise dimensions of the samples and adjustment of the rolling gap in such a way, that degree of spreading was maximised and measurements of dimensional changes of the samples was more precise. The necessary enhancement of engagement ability of the rolls was ensured by bevelling of the tapered part of the sample, which thus gained a semi-wedge shape. Samples from three dozens of steels, which differed significantly by their chemical composition, were rolled under otherwise identical conditions. The measured results led to a formulation of conclusions concerning the influence of rolling temperature and particularly of the selected elements on the degree of spreading of steels.