Усовершенствованный метод расчета площади контактной поверхности соприкосновения металла с валками при поперечно-винтовой прокатке

Abstract

The universal methodology based on the mathematical model of metal deformation during cross rolling process has been proposed to improve accuracy in determination of shape and area of contact of the pipe billet with a roll. The indicated mathematical model allows stepwise building of deformation zones contour with due consideration of consistency in development of the rolled shell contour in deformation zone. Area of the roll contact with the shell has a form of curved surface significantly changing as a function of the shell movement path during the rolling process. Determination of the contact area of metal surface with the rolls during cross rolling process is fulfilled with the use of widespread graphic packages like QFORM, DEFORM, ANSYS, SOLIDWORK, Compass, AUTOCAD. The proposed methodology takes care on a continuous basis of changing parameters of a deformable body (radius of billet, shell wall thickness) w.r.t. rolling axis with due consideration of a roll turning. The use of proposed simulation method featuring minimum assumptions allows receipt of actual value of the contact area of metal with a rolling tool for each deformation area spaced from each other at a half step of the shell feed. It becomes possible to study actual deformation zone while the shell moves with due consideration of its deformation in the deformation zone. The contact area of the metal with the roll obtained from its graphic construction well coincides with results of full-scale industrial experiment and it is more accurate by 20 % as compared with calculation using method based on approximated description of deformation zone shape by ellipses. The contact area data obtained serve as an input for calculation of energy parameters for piercing process (rolling-off). Comparative analysis showed that deviation of values of the metal force on the roll generated by simulation is not more than 10 % as against experimental data. The proposed methodology can be used for analyzing cross rolling processes: piercing, expansion (elongation). The results obtained allow us to come to conclusion on possibility of using the developed principle describing free rolling-off contour during development of computer algorithms for simulation of cross rolling process.