Assessment of shear deformations in two-roll screw rolling processes based on computer simulation

Finite Element Method (FEM) computer simulation of two-high screw rolling of stainless steel billet was carried out using QForm software. Two-high rolling mill had guiding shoes and rolls feed angle was set 6,12,18 and 24 degrees. Forming features and shear strain were estimated as a result of computer simulation. Tracking point option of QForm software was applied for this purpose. There were 3 groups of points, each group consisted 8 points and formed cube contour. Cube has 1 mm edge and each point was cube’s vertex. One cube was in the center of the billet, the second – 0,5 radius distance from the billet center, the third – at the surface of the billet. As a results of simulation, cubes transformed into polyhedrons. It was assumed, that if cube transform into rectangular parallelepiped or some figure close to that, then shear is considered as pure. If cube transform into parallelepiped which is different from rectangle, then shear considered as simple. It was established that pure shear is most clearly distinct at the center of the billet for at all feed angles of rolls. The further from the billet center, the more is simple shear severity. Investigation results show that strain state at 6 and 12 degrees rolls feed angles is less uniform compared to the same at 18 and 24 degrees rolls feed angles. Designed technique and results obtained due its application allowed confirmation and addition of radial-shear rolling (RSR) concept, i.e. screw rolling with increased rolls feed angles (18 degrees and more).The study was supported by the grant of the Russian Science Foundation No. 23-19-00775, https://rscf.ru/project/23-19-00775/.