Chatter in the Strip Rolling Process, Part 1: Dynamic Model of Rolling

1998 ◽  
Vol 120 (2) ◽  
pp. 330-336 ◽  
Author(s):  
I-S. Yun ◽  
W. R. D. Wilson ◽  
K. F. Ehmann
Keyword(s):  
Dynamic Model ◽  
Coulomb Friction ◽  
Rolling Force ◽  
Rolling Process ◽  
Rate Of Change ◽  
Two Dimensional ◽  
Entry And Exit ◽  
Strip Rolling ◽  
Coulomb Friction Law ◽  
Rolling Torque

This paper presents the development of a new dynamic model of the rolling process which provides estimates of the variations in exit gage, strip speed and tension at entry and exit, rolling force and rolling torque in response to variations in roll separation as well as the rate of change of the roll spacing. This two-dimensional dynamic model employs the Tresca friction factor approach instead of Amontons-Coulomb friction law.

Chatter in the Strip Rolling Process, Part 2: Dynamic Rolling Experiments

1998 ◽  
Vol 120 (2) ◽  
pp. 337-342 ◽  
Author(s):  
I-S. Yun ◽  
K. F. Ehmann ◽  
W. R. D. Wilson
Keyword(s):  
Dynamic Model ◽  
Rolling Force ◽  
Rolling Process ◽  
Experimental Results ◽  
Strip Rolling ◽  
Dynamic Component ◽  
Simulation Results ◽  
Roll Gap

This paper presents the results of dynamic rolling experiments examining the variations in rolling force, back tension and roll gap in response to a sinusoidal dynamic component of various frequencies being superimposed on the roll gap or back tension. Comparisons between the experimental results and the corresponding simulation results are also presented to investigate the validity of the new dynamic model of the rolling process presented in Part 1 of this paper.

scholarly journals New Numerical Solution of von Karman Equation of Lengthwise Rolling

2015 ◽  
Vol 2015 ◽  
pp. 1-20 ◽  
Author(s):  
Rudolf Pernis ◽  
Tibor Kvackaj
Keyword(s):  
Contact Stress ◽  
Rolling Force ◽  
Rolling Process ◽  
Normal Contact Stress ◽  
Normal Contact ◽  
Circular Arch ◽  
Relative Stress ◽  
Roll Flattening ◽  
Polygonal Curve ◽  
Rolling Torque

The calculation of average material contact pressure to rolls base on mathematical theory of rolling process given by Karman equation was solved by many authors. The solutions reported by authors are used simplifications for solution of Karman equation. The simplifications are based on two cases for approximation of the circular arch: (a) by polygonal curve and (b) by parabola. The contribution of the present paper for solution of two-dimensional differential equation of rolling is based on description of the circular arch by equation of a circle. The new term relative stress as nondimensional variable was defined. The result from derived mathematical models can be calculated following variables: normal contact stress distribution, front and back tensions, angle of neutral point, coefficient of the arm of rolling force, rolling force, and rolling torque during rolling process. Laboratory cold rolled experiment of CuZn30 brass material was performed. Work hardening during brass processing was calculated. Comparison of theoretical values of normal contact stress with values of normal contact stress obtained from cold rolling experiment was performed. The calculations were not concluded with roll flattening.

Rigid Plastic FEM Model of Fast Solution to Strip Rolling

2011 ◽  
Vol 704-705 ◽  
pp. 358-363
Author(s):  
Rui Bin Mei ◽  
Chang Sheng Li ◽  
Xiang Hua Liu ◽  
Li Bao
Keyword(s):  
Rolling Force ◽  
Rolling Process ◽  
Computational Time ◽  
Rolling Schedule ◽  
Strip Rolling ◽  
Rigid Plastic ◽  
Fem Model ◽  
Online Application ◽  
Fast Solution ◽  
Good Agreement

Rigid plastic finite element method (RPFEM) is one of the most efficient numerical methods during the rolling process. Realizing FEM online application has been main target for many researchers. The influence of compile method, elements number, compressible parameter, friction factor and convergent criteria were investigated and RPFEM model of fast solution to strip rolling was proposed in this work. Compile method and compressible parameter have less influence on calculated rolling force. However, the iteration steps are reduced and computational efficiency is improved greatly with compile method of release and compressible parameter 0.01. The change of calculated rolling force becomes less but iteration steps become more and more with the increment of elements number. Both accuracy and efficiency is satisfying with the change of elements number from 50 to 200. In addition, the typical rolling schedule from a certain plant has been solved with the developed program FFEM-2D by FORTRAN. The predicted rolling force has a good agreement with the measured value. The iteration steps change from 12 to 36 and computational time is less than 200(ms) with the model in one pass rolling. Therefore, the accuracy is satisfying and computational time fully meets the basic requirements of FEM online application. Keywords: Rolling; RPFEM; Fast solution; Computational time

scholarly journals A New Method of Manufacturing Hollow Shafts via Flexible Skew Rolling

2021 ◽  
Vol 2101 (1) ◽  
pp. 012010
Author(s):  
Xiaoqing Cao ◽  
Baoyu Wang ◽  
Wei Guo ◽  
Zhidong Ju
Keyword(s):  
Rolling Force ◽  
Rolling Process ◽  
Fe Model ◽  
Forming Process ◽  
Hollow Shaft ◽  
Process Adjustment ◽  
Rolling Load ◽  
Rolling Torque ◽  
Skew Rolling ◽  
Hollow Shafts

Abstract The existing rolling process of large and long axle parts, such as the cross wedge rolling (CWR) process, requires special molds and larger equipment. Flexible skew rolling (FSR) hollow shafts with mandrel is a near net-shape rolling technology which can achieve the diversified production of rolled parts without special molds. It has significant advantages such as small equipment tonnage, small die size, low rolling load, simple process adjustment, and especially suitable for multi-variety and small-batch production. This paper proposes hollow train shafts formed by FSR with mandrel. Reasonable parameters were selected for experiments, and the forming process was calculated by finite element (FE) software. The experimental results are consistent with the simulation results, indicating that the FE model is reliable. The rolling force and rolling torque are analyzed by simulation. Finally, the microstructure of different positions of the rolled-piece is analyzed, and the microstructure of the rolled part is refined. It is provide a feasible scheme for the rolling of large hollow shaft parts.

scholarly journals Multiple-Modal-Coupling Modeling and Stability Analysis of Cold Rolling Mill Vibration

2016 ◽  
Vol 2016 ◽  
pp. 1-26 ◽  
Author(s):  
Lingqiang Zeng ◽  
Yong Zang ◽  
Zhiying Gao
Keyword(s):  
Dynamic Model ◽  
Rolling Mill ◽  
Process Model ◽  
Rolling Force ◽  
Rolling Process ◽  
Dynamic Responses ◽  
System Stability ◽  
Force Model ◽  
Structure Model ◽  
Rolling Mill Vibration

An effective dynamic model is the basis for studying rolling mill vibration. Through analyzing characteristics of different types of vibration, a coupling vibration structure model is established, in which vertical vibration, horizontal vibration, and torsional vibration can be well indicated. In addition, based on the Bland-Ford-Hill rolling force model, a dynamic rolling process model is formulated. On this basis, the rolling mill vertical-torsional-horizontal coupled dynamic model is constructed by coupling the rolling process model and the mill structure model. According to this mathematical model, the critical rolling speed is determined and the accuracy of calculated results is verified by experimental data. Then, the interactions between different subsystems are demonstrated by dynamic responses in both time and frequency domains. Finally, the influences of process parameters and structure parameters on system stability are analyzed. And a series of experiments are conducted to verify the correctness of these analysis conclusions. The results show that the vertical-torsional-horizontal coupled model can reasonably characterize the coupling relationship between the mill structure and the rolling process. These studies are helpful for formulating a reasonable technological procedure of the rolling process and determining a feasible dynamic modification strategy of the structure as well.

General Solution to Bond Rolling of Unbounded Sandwich Sheet with Outer Soft and Inner Hard Layers Considering Coulomb Friction

2012 ◽  
Vol 579 ◽  
pp. 68-77 ◽  
Author(s):  
Sai Chih Pan ◽  
Gow Yi Tzou ◽  
Yeong-Maw Hwang
Keyword(s):  
Shear Stress ◽  
Coulomb Friction ◽  
Rolling Force ◽  
Horizontal Stress ◽  
Contact Interface ◽  
Useful Knowledge ◽  
On Line ◽  
Sandwich Sheet ◽  
Rolling Torque ◽  
Roll Gap

This study derives the stress field of the bond rolling of unbounded sandwich sheet with outer soft and inner hard layers at the roll gap considering Coulomb friction between the roll and the sandwich, and Coulomb friction at the interface of the unbounded region. Due to the sandwich sheet unbounded before rolling, three-layer sheets are not bonded firmly. The neutral point between the roll and the sandwich sheet, the rolling pressure distribution along contact interface between the roll and sandwich sheet, the horizontal stress of whole sandwich sheet, the horizontal stresses in the component layers of sandwich, the shear stress at the interface of sandwich sheet, the rolling force, and rolling torque, etc. are effectively calculated via this model. Furthermore, it is of great important to obtain the bonding point at the interface and the thickness ratio of sandwich sheet at the exit from this study. Additionally, the bonding conditions of the unbounded sandwich sheet are found to avoid the failure in bond rolling. This study proposed is suitable for the on-line bond rolling; it offers useful knowledge to conduct the experimental bonding conditions.

Research on the Minimum Rolled Thickness of Strip Steel in Cold Tandem Rolling

2014 ◽  
Vol 622-623 ◽  
pp. 993-999
Author(s):  
Shou Min Wu ◽  
Lie Sheng Wei ◽  
Gang Huang
Keyword(s):  
Coulomb Friction ◽  
Production Efficiency ◽  
Field Experiments ◽  
Rolling Force ◽  
Rolling Process ◽  
Force Model ◽  
Constraint Condition ◽  
Steel Rolling ◽  
Strip Steel ◽  
Fully Integrated

In consideration of the zone between rolls and deformed area where friction at roll-sheet interface is lower than predetermined value of Coulomb friction in rolling process of ultrathin strip steel, fully integrated with equipment and process features of cold tandem mills, after a large number of field experiments and theoretical studies, on the basis of the improvement of ultrathin strip steel rolling force model, with the allowable rolling pressure and production efficiency as constraint condition, a new calculated theory about the minimum rolled thickness was put forward. What’s more, the theory will be used in the productive practice of 1220 five-rack cold tandem mills of China. The technique has the value to be further popularized.

A New Calculating Model of Rolling Pressure during Temper Rolling Process

2010 ◽  
Vol 443 ◽  
pp. 39-44
Author(s):  
Xiao Zhong Du ◽  
Zheng Yi Jiang ◽  
Zhen Hua Bai ◽  
Xiang Long Yu ◽  
Zhong Yuan Zhang
Keyword(s):  
Mathematical Models ◽  
Internal Stress ◽  
Rolling Force ◽  
Rolling Process ◽  
Temper Rolling ◽  
Entry And Exit ◽  
Rolling Mills ◽  
Stress Boundary Conditions ◽  
Stress Boundary ◽  
Small Plastic Deformation

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.

scholarly journals Thin Strip Profile Control Capability of Roll Crossing and Shifting in Cold Rolling Mill

2013 ◽  
Vol 773-774 ◽  
pp. 70-78 ◽  
Author(s):  
Abdulrahman Aljabri ◽  
Zheng Yi Jiang ◽  
Dong Bin Wei ◽  
Xiao Dong Wang ◽  
Hasan Tibar
Keyword(s):  
Cold Rolling ◽  
Rolling Mill ◽  
Rolling Force ◽  
Work Roll ◽  
Rolling Process ◽  
Thin Strip ◽  
Strip Rolling ◽  
Strip Shape ◽  
Strip Profile ◽  
Profile Control

Controlling cold strip profile is a difficult and significant problem has been found in industry during thin strip rolling. At present choosing the new type of strip rolling mill is the one of main methods to control the strip shape quality in cold rolling. The influences of rolling process parameters such as the work roll cross angle and work roll shifting on the strip shape and profile of thin strip are recognised throughout this study. The results show that the roll crossing and shifting is efficient way to control the strip shape. The increase of the work roll crossing angle would lead to improve the strip profile significantly by decreasing the exit strip crown and edge drop. The strip profile would be enhanced if the axial roll shifting was increased. Moreover, the total rolling force was analysed in detail by changing the roll cross angle and axial shifting roll.

scholarly journals The Analytic Study on the Heavy Steel Plate Snake Rolling with the Same Roll Diameters

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Lian-yun Jiang ◽  
Qing-cheng Meng ◽  
Chun-jiang Zhao ◽  
Shou-xin Wang ◽  
Yan-wei Liu
Keyword(s):  
Steel Plate ◽  
Rolling Force ◽  
Rolling Process ◽  
Slip Zone ◽  
Mechanical Parameters ◽  
Rolling Method ◽  
Set Up ◽  
Rolling Torque ◽  
Inner Region ◽  
Rolling Deformation

The deformation in the inner region along the thickness of the heavy steel plate can be improved by snake rolling method. Then the microstructure and property will be refined and the crack in the inner region may be avoided. Therefore, the in-depth research on snake rolling method mechanics parameter modeling should be conducted to guide production. A snake rolling process with the same roll diameters and different angular velocity was conducted in this paper. The rolling deformation zone will be divided into back slip zone, front slip zone, cross shear zone, and reverse deflection zone according to the direction of the friction during the snake rolling process. The four zones may not exist at the same time. The boundary conditions of existence of the back slip zone, front slip zone, and cross shear zone were established according to the relationship between threading angle and neutral angle. The calculating models which were used to calculate the snake rolling mechanical parameters including the rolling force and rolling torque were set up. The calculated models of unit compressive pressure in the four zones were set up by the slab method, and on this basis the accurate calculating models of the rolling force and rolling torque were set up according to the composition of the rolling deformation zone and the boundary condition. The mechanical parameters were calculated by the analytical method and the numerical method, and the relative deviation is less than 6% which can satisfy the industrial requirement. The present analytical model can predict the characteristics during snake rolling easily and quickly and it is also suitable for online control applications.

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