Ověření rozměrové přesnosti u předvalků vyrobených Mannesmannovou technologií

Abstract

By measuring the diameters and wall thickness in cross sections of three selected rolled billets, which are pierced by oblique rolling in the rolling mill Velky Mannesmann, their dimensional accuracy was investigated. It is clear from the obtained results that in all three examined semi-finished rolled products, due to several factors acting during piercing, this demanding process was destabilized. Due to the weight of the semi-finished rolled products in combination with the effect of the pressure roller and probably also due to the intervention of the operators of the piercing rolling stand, the cross section of all examined billets in their head part (it was finally pierced) had a significantly asymmetrical shape. In the case of the largest semi-finished rolled product, which also had the largest weight of all the investigated semi-finished rolled products, this undesired asymmetric cross section was found practically along its entire length.