Упругое проскальзывание в задачах обработки металлов давлением

Abstract

On level with plastic deformations an elastic interaction between elements of rolling equipment and rolled metal takes important place in sheet steel rolling. Contacts between work roll and rolled band, between work and backup rolls are examples of such interactions. In contrast to the work roll and rolled band contact interaction, which is the subject of many detailed theoretical and experimental investigations, the work roll and backup roll contact is considered only from the point of view of rolling load redistribution in multirolled systems. However, wide application of profiled rolls’ axial shifting in unscheduled rolling technology demands further investigations of elastic interaction with slippage. Inconstancy of distances between rolls’ pivot pins and contact surfaces leads to local mismatch between peripheral speeds of work and backup rolls. This effect is a reason of slippage. Later on it leads to uneven wear of work rolls. It must be necessarily taken into account while developing roll contours for axial shifting and algorithms for unscheduled rolling technology with automatic profile and flatness control for ensuring of rolled band’s profile which satisfies consumer’s demands. In the article there is formulated target setting of elastic contact of two osculating half-planes under speed asymmetry and compressive load. Principle of virtual work was used. There are obtained approximate solutions for completely elastic earth describing deflected mode without relative speed (Hertzian problem) and under speed asymmetry, which leads to appearance of slip zones on a contact surface. Influence of acting load, speed asymmetry, constant of friction and Poisson's ratio on slip zones‘ lengths is shown. In the article there are presented dependencies for correction of wear factors of work rolls, which are used in finishing train’s stands of wide-strip hot rolling mill with equipment for axial shifting. These dependencies are used to determine wear values of profiled work and backup rolls.