The vibration characteristic technical indexes of six-high cold strip rolling mills are not given, and thus the chatter vibrations cannot be predicted and prevented. The strip rolling mills can be divided into the non-statically determinate and statically determinate mills according to the statically determinate theory of mechanism. This statically determinate characteristic of the mill does not be distinguished in the traditional mill vibration analysis. In this paper, for these two distinct mill configurations, a complete spatial vibration characteristic analysis involving six degree of horizontal, vertical, axial, torsional, cross and swinging vibration will be presented based on the modified multi-body Riccati transfer matrix method. The results demonstrate that the vibration characteristics of the statically determinate mills are much better that that of nonstatically determinate ones, which significantly indicates the perniciousness of the offset distance and uncontrolled side clearance, and clarifies the necessity of upgrading of the traditional mills.

The theory of micro dimensional behavior on rolling mill is used for a typical 450 mm hot plate four-high mill. A statically determinate device is adopted on the back-up roll system to adapt to the micro-dimensional deflection. We replace the traditional single base with the force divided base for the rolling load. To make the rolls parallel, a worm-screw device is set in the chock, with a clearance between the chock and the stand window to allow convenient roll replacement and retain a thermal expansion space. In the new mill, the center line of the roll body is constant when the rolling is stopped or running. It can be predicted that the mill will be strengthened two times and the roller bearing life will be prolonged ten times.

For guiding production effectively and revealing rolling mechanisms, the analysis of rolling-pressure distribution regulation is very important. Because rolling strip belongs to multi-object contact engineering problem which involves coupling deformation, obviously the accuracy of disaggregate mathematical method is low. Therefore, in this paper,it is developed that multi-object, elasto-plastic and frictional contact multipole Boundary Element Method (BEM) by Fortran program. It can simulate five object synchronous contact accurately without artificial assumption.The three dimensional rolling-pressure distribution regulation of rolling strip has been obtained through this program. Through testing and calculating the load properties of bearing, the result shows that it is accordant for test and calculation. Therefore, multi-pole BEM is one of the effective numerical analytic tools of rolling contact problem, and the obtained result of rolling-pressure distribution can provide for reference value for analyzing rolling strip.

The contemporary four-high mills are unstable and four-high rolling mill vibrations take place in six DOF leading to spatial behaviors involving vertical, horizontal, axial, reverse, cross and swinging vibration modes resulting in complex relative motions between the rolls. In this paper, a spatial vibration characteristic analysis of two four-high rolling mills with different stability will be presented based on the transfer matrix method (TMM) and Finite Element Method (FEM). The natural frequency and mode shape of four-high rolling mill are obtained. Vibration experimental results will be presented to prove the validity of the spatial vibration of rolling mill.