Xiao Zhong Du

Strip Shape Analysis of Asymmetrical Cold Rolling of Thin Strip

Strip shape control during cold rolling of thin strip is a challenge in rolling practice. In the paper, finite element model of strip shape during cold rolling of thin strip in asymmetrical rolling case was successfully developed, and the strip shape such as the thickness distribution along the strip width have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape in practice.

An investigation of mechanical non-sinusoidal oscillation of continuous casting mold

In this paper, a new technique to set up non-sinusoidal oscillations of the mold in continuous casting is presented. The waveform functions of this non-sinusoidal oscillation technique and operational parameters are analyzed and the design to realize the non-sinusoidal oscillation of mold is presented. It is anticipated that this technique will be widely applied as it has many advantages such as lower investment and maintenance cost, simple equipment which is easy to manufacture and maintain.

Modeling of Strip Shape during Cold Rolling of Thin Strip

Strip shape is an important factor affecting the strip quality significantly during cold rolling of thin strip. In the paper, finite element simulation models of the strip shape in cold rolling for both symmetrical and asymmetrical rolling cases were successfully developed. The strip edge drop and the effect of the rolling force on the strip shape (the thickness distribution along the strip width) have been obtained. The developed finite element model has been verified with the experimental value, which shows they are in good agreement. The obtained results are applicable to control the rolled thin strip shape during cold rolling practice.

FEM Simulation of the Slab Edge Rolling in Unsteady Rolling Stage

According to characteristics of adjusting width by vertical roll at a certain steel corporation, unsteady deformation of head and tail of slab during edge rolling was analyzed by FEM simulation on base of a commercial software. The effect of several process conditions on the cross-section deformation and width loss of slab were also analyzed.

Analysis of Cold-Rolled Strip Profile in UCM Mill by Finite Element Method

In order to analyze the effect of entry strip thickness, entry strip crown and intermediate roll shifting on strip profile and rolling force distribution, a three dimension finite element model of rolls-strip in UCM mill was established and employed. The results showed that the increases of entry strip thickness and entry strip crown would lead to the increase of exit strip crown and edge drop under the same total rolling force; the strip crown and edge drop would be decreased if the intermediate roll shifting δi was decreased. Moreover, the rolling force distribution also was analyzed in details by changing the entry strip thickness, the entry strip crown and the intermediate roll shifting.

A new calculating model of rolling pressure during temper rolling process

A set of new mathematical models have been developed to calculate the temper rolling force of 2050 strip temper rolling mill. Based on the fact of small plastic deformation and elastic deformation occurring on the entry and exit of the deformation zone, new stress boundary conditions are described. The inhomogeneous distribution of internal stress in thickness direction is taken into account in the models, instead of uniform internal stress and assumption of plane strain traditionally. The new mathematical models have been applied into the temper rolling of 2050 hot rolling mills with good results. Comparison of calculated values and testing values for nine typical products has been given. The result shows that the calculated value of rolling force of temper mill is accurate.

Asymmetric Shape Control Theory and Practice in Cold Strip Mills

In cold rolling process, asymmetric shape defects are still a common problem to strip quality. For the mills with inverse symmetry roll shifting system, different roll wear and thermal contour of top roll system and bottom roll system could cause asymmetric shape defects during shifting operation. In this paper, three dimension finite element simulation models of inverse shifting roll system were established to calculate the parameters and to analyze the effects. Based on the idea in the mill engineering that mill style option depended on the product grade, shifting weakness was evaluated and the opinion of limit shifting was suggested. To improve control effect to asymmetric shape defects in cold rolling, shape control system with asymmetric shape control ability is developed, including asymmetric edge drop control at upstream stands and asymmetric flatness control at last stand. The further improvement of asymmetric shape control theory and practice is the key way to reach the higher precision of shape quality in cold strip mills.

Modelling of Strip Shape and Profile during Cold Rolling of Ultra Thin Strip

In this paper, finite element models of the strip shape during cold rolling of ultra thin strip in both symmetrical and asymmetrical rolling cases have been successfully developed, and the strip shape such as the thickness distribution along the strip width has been obtained. The strip shape and edge drop are discussed under both symmetrical and asymmetrical rolling conditions. Simulation results show that the asymmetrical rolling can reduce strip edge drop dramatically. The work roll edge curve also affects strip shape significantly. The developed finite element model has been verified with the experimental values.

Equation of Shape Control and Edge Drop on UCMW Tandem Cold Mill

Edge drop of strip and sheet is a key technological issue besides of gauge control and shape control during the process of wide strip rolling, the reasonable control procedure of edge drop can increase the qualified product ratio, as well the quality and performance of product, it is especially effective for the silicon steel sheet, tin sheet and automobile body sheet. Therefore, more researchers focus on the edge drop of strip and its control technology in recent years. In this paper, a new strip profile control equation is established originally, according to the ways of strip shape control technology of large-scale tandem cold rolling mills. The new equation describes both the shape control and edge drop control. Some verification is developed in the equation based on the 1420mm UCMW tandem cold mill. The research result about mechanics of edge drop and its control have been applied in tandem cold rolling mill. The good result is obtained according to the field measured data, and the control precision is increased greatly.

Development of a Combined Shape and Gauge Control Scheme Based on Function Φ

Combined shape and gauge control is a hot issue in continuous hot plate and strip rolling field. Due to the coupled function of shape and gauge control in rolling process, mutual effects must be considered when shape control is carried out. Traditional shape and gauge control theories are of independent and the control systems are also separated, so it is difficult to ensure the quality of shape and gauge simultaneously. Based on the shape theory of shape and gauge control and function Φ derived from the load distribution method of Ichiro Imai , a combined shape and gauge control scheme was developed, which can adjust rolling regulations on-line according to the deviation of strip crown measured at the exit of the rolling mill. The method can ensure gauge precision while strip crown is adjusted and the purpose of combined shape and gauge control is reached.