Dynamic Torque Limitation Principle in the Main Line of a Mill Stand: Explanation and Rationale for Use

V.R Gasiyarov,V.R Khramshin,S.S Voronin,O.A Gasiyarova,T.A Lisovskaya

doi:10.3390/machines7040076

Abstract

This paper substantiates why it is necessary to limit the dynamic loads in stand shafts when closing angular gaps. The paper is a feasibility study of a concept developed specifically to limit each of the factors that affect amplitude of the dynamic torque; limitations applied are determined on a case-by-case basis. The research team studied the components of elastic torque in a dual-mass electromechanical system of Mill 5000 caused by vibrations arising from the elasticity of transmission as well as from the vibrations caused by elastic collision itself. It is shown that the lowest possible pre-acceleration is necessary for decreasing the dynamic coefficient at a near-nominal load torque. A principle of limiting dynamic loads when closing an angular gap is proposed, which implies collecting tachograms of an electric drive subjected to positive or negative acceleration before and after the fed metal is captured. The research team has developed drive control principles to implement this approach. The recommendation is to upgrade the electric drives of the reversing stand in Mill 5000.

Highlights

One of the most important applied research issues, resolving which will reduce the risk of accidents in the roll lines of a mill, is to limit the shock loads occurring when rolls capture the fed metal.Unacceptable loads are mainly caused by the difference in the peripheral speed of rolls and the speed of workpiece being fed into a stand; or by the closure of angular gap in spindle connections when metal is captured [1].Multiple papers have covered limiting the horizontal component of dynamic torque, including [2,3,4,5,6,7]
The amplitude of oscillatory processes may be considerably higher than the maximum part of the torque caused directly by shock play closure. Analysis of these and other waveforms demonstrates that pre-closing the angular play by means of accelerated capture is not sufficient to reduce the elastic torque of the shaft
It was observed that this option is not guaranteed to limit the dynamic torque in the engine, it helps to achieve a satisfactory transient for the elastic torque in the shaft [22]

Summary

Introduction

One of the most important applied research issues, resolving which will reduce the risk of accidents in the roll lines of a mill, is to limit the shock loads occurring when rolls capture the fed metal. Limiting the effects of angular play is relevant for almost all shock-sustaining rolling mills, including plate Mill 5000 of Magnitogorsk Iron and Steel Works (MMK), PJSC. In recent decades, it has become especially relevant as MMK has expanded its assortment and begun to roll difficult-to-form steel required for manufacturing large-diameter pipes [8,9,10]. The current literature contains no data on implementing such controls in plate rolling mills This is why limiting the dynamic loads in electromechanical roll systems is a relevant research issue; find studies of Mill 5000 below

Statement of Problem

Analysis of Elastic Torque Components when Choosing Play

Dynamic Torque Limitation Principle

Findings

Discussion of the Results

Conclusions