Investigation of influence of plate rolling parameters on the product quality

During plate rolling in most cases a breakdown of symmetry conditions of the strip deformation relative to the upper and lower rolls takes place. The rolling process becomes an asymmetric one. This phenomenon causes an adverse bending of the strip towards the lower or upper roll. Subsequent finishing operations do not ensure the exclusion of the deformed (wavy) shape, since the strip has a high rigidity. With this production, large technological waste, associated with the undulation of the front end of the strip arises. In addition, the work rolls of the rolling mill and auxiliary equipment are subject to increased wear. The introduction of controlled asymmetry into the rolling process by differentiating speed of rotation of the work rolls can be one of the ways to prevent this phenomenon. Using of asymmetry allows to change the stress and strain state in the deformation zone. This method does not increase the load on the rolling stand and the gear of the rolling mill. The paper presents results of investigation of plate rolling parameters (billet feeding angle, degree of deformation, value of the asymmetry coefficient of rolls rotation speed) on the strip curvature. The work was carried out according to conditions of hot rolling of steel grade S355J2+N. For numerical simulation of the rolling process the coefficients of the Hensel–Spittel function were refined. The authors conducted a study of rolling of plates using two types of asymmetry, a geometric (as a result of feeding the workpiece at an angle) and a kinetic (by changing the speed of rotation of individual rolls). The analysis of the results was carried out using numerical simulation based on the modern Forge soft- ware package. According to the results of the work, an analysis of the influence of the parameters of plates hot rolling on the metal flow in the deformation zone is presented. The conditions for reducing the curvature of the end of the strip are determined. The expediency of introducing a controlled asymmetric rolling process by application of different speeds of rotation of the work rolls is shown.