Determination of setting parameters of screw insertion on two-roll mills

Mathematical dependences for the description of basic geometric parameters of the deformation zone with a screw insertion on two-roll mills were developed. The obtained expressions take into account the distortion of the roll gap caused by the rotation of the piercer rolls to a feed angle at any cross section and can be used for the mathematical description of twin screw rolling mills with mushroom and barrel rolls operating at higher filing angles. For a sufficiently precise mathematical description of the geometric parameters of the deformation zone dependencies were proposed that allow to determine the distance from the rolling axis to the roll surface at any cross section of the deformation zone. The distance from the rolling axis to the roll surface was defined on the assumption that the radius of the roll on its main meridional plane is negligible. The comparison of obtained mathematical relationships with solid modeling, based on surface modeling with boundary representation of solids and implemented in the SAD programme Compass-3D showed good convergence and legitimacy of the accepted assumption. On the basis of expressions obtained a method to determine main parameters of the process of tuning screw firmware was developed, i.e. the distance between the rollers in a roll pinch; mandrel extension outside rolls’ survivors; compression in front of the mandrel toe, and the distance from the workpiece grip of the roll to the mandrel toe. The developed mathematical relationships are also suitable for the development of the rolling tool calibration of piercing mills (mandrels and rolls) and for the analysis according to the deformation scheme during the screw insertion process.