Fundamental Investigation into the Mechanics of Pendulum Rolling Process

Abstract

As rolling mill development has progressed the intermittent action mill has emerged and established itself in a position of importance. To optimise any process it is necessary to have a full knowledge of the mechanics involved. Thus, an investigation into the mechanics of the pendulum riling process which is intermittent in action has been undertaken to define the important parameters and their associated effects and to analyse theoretically the effects of these parameters on the resulting loads and torques. The analysis is based on the indentation theory advanced by Hill and it is described to show its applicability to the case of pendulum mill rolling. The analysis is put forward in the form of a mathematical simulation of the process requiring solution on a digital computer. Allowances are made for the elastic distortions of the pendulum arms and work rolls and the variation of the yield stress of the material through the swept arc. The resultant variation of a defined geometrical ratio is used an conjunction with the indentation theory to obtain the resultant load and torque waveforms. Since the experimental procedure attempted to minimise temperature effects, no account was taken of these effects in the final analysis. The mill was modified such that repeatable results could be obtained. The relevant loads, torques, tensions and speeds required to define the system completely were monitored for a realistic range of operating conditions and reduction ratios. All the results monitored were recorded on two synchronised ultra-violet recorders. From the observations made, it was concluded that the indentation theory explains many of the practical effects produced in pendulum mill rolling. Further, the defined geometrical ratio was shown to be important. The analysis was used to predict the peak loads occurring and gave good agreement with the loads obtained by experiment.