PROSPECTS FOR USE OF THE RESERVE FORCES OF FRICTION ON CONTACT SURFACE IN DEFORMATION ZONE AT ROLLING TO INCREASE PROCESS EFFICIENCY

Rolling process is carried out due to power supplied to the center  of deformation using contact friction forces. Rolling takes place in two  stages  – the capture stage and the steady-state process. The capture  stage determines possibility of deformation in rolls. During this period,  retracting forces of friction are used with maximum efficiency. The  main stage of rolling is the steady-state stage of the process, where  contact friction capabilities are not fully used and reserve of friction  forces is created, which can increase efficiency of rolling process. To  balance excessive friction forces on contact surface in deformation  zone during the steady-state process, zones of advance and adhesion  appear. Their length characterize amount of excessive friction forces.  Theoretical dependences for determining slip and adhesion zones are  given taking into account variety of rolling factors. Estimation indicator of abilities of friction forces reserve at the steady-state stage is  offered as well as dependence for its definition. It is analytically established that in steady-state stage of rolling on smooth rolls with ratio    α/μз  =  1 it is possible to supply 1.7  –  2  times greater energy due to  exis ting reserve of friction force than at the stage of capture at a lower  ratio α/μз ; these numbers are even higher for rolling on grooved rolls.  Dependence which determines amount of additional power provided  by friction forces reserve is given. Promising directions of using friction forces reserve at the steady- state stage of rolling are provided to  improve its efficiency. On the example of rolling in drive – non-drive  stand, an increase in efficiency (Efficiency Ratio) of the main line of  rolling mill is established with more efficient use of friction forces  at the steady-state stage of rolling process. Theoretical dependences are given to determine Efficiency Ratio at usual rolling process and at  more full use of friction forces reserve.

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