Effect of the kinematics of rotary rolling on the fineness of the structure of hypereutectoid silumins

Abstract

It has been established experimentally that the internal layers of cylindrical semifinished products that are made of hypereutectoid silumins and contain embedded lengthwise pins do not intermix during rotary rolling. The experiment also determined that the angles through which different concentric internal layers of the semifinished product (ω₁ > ω₂ > ω₃) are twisted are different and depend on the radii of those layers (R′₁ > R′₂ > R′₃). This finding contradicts the hypothesis of rigid sections in the classical theory of the strength of materials. An analytic relation (empirical formula) is found to describe the pitch of the internal layers of metal flow in relation to the main parameters of the rotary-rolling operation (the feed angle α and deformation ε) and the radius of the given internal layer (R′_x). Another empirical formula is proposed to determine the angle of inclination of the helical lines along which the metal inside the rolled specimen is displaced. A mathematical model is constructed to describe the dependence of the ductility properties of hypereutectoid silumin alloys on changes in the dimensions of the silicon crystals in the alloys when semifinished products made of these alloys are deformed by rotary rolling.