scholarly journals Analysis of 3D Plastic Deformation in Vertical Rolling Based on Global Weighted Velocity Field

Author(s):  
Boxin Yang ◽  
Haojie Xu ◽  
Qi An

Abstract Energy method is an essential theoretical approach to analyze plastic forming, which is widely used in rolling. An analysis model for vertical rolling process is established according to energy theory. By using global weighted method firstly, the 3D continuous velocity field, strain rate field and the corresponding power functional are proposed. The unknown variables are solved numerically based on the principle of minimum energy. Then, deformation parameters and rolling force are determined. The analysis on specific examples with the width reduction rate of 0.03~0.05 shows that the theoretical prediction value of weighted model is in good agreement with experimental results. Moreover, the effects of several shape and rolling parameters on rolling force, rolling power and edge deformation are studied. Both the width reduction rate and initial slab thickness have significant influences on dog-bone size and rolling force. A wider slab slightly increases the nonuniformity of dog-bone deformation. An increase of vertical roller radius can weaken the edge deformation.

2012 ◽  
Vol 602-604 ◽  
pp. 1864-1868 ◽  
Author(s):  
Lan Wei Hu ◽  
Xia Jin ◽  
Lei Shi ◽  
Sheng Zhi Li

A 3-D thermal-mechanical model was built to simulate the hot rolling process of medium plate, with the aid of nonlinear commercial FE code MSC.SuperForm on a company's actual process parameters. The hot rolling process of single-pass which slab thickness is 180mm was simulated, and the influence of pass reduction on metal flow, stress-strain field, contact stress and rolling force were researched. The study revealed that pass reduction should be at least 20% by increase depress in pass in addition to rolling efficiency. As that, rolling efficiency be increased, roll contact stress be brought down, and its service life be prolonged. And metal plastic strain enhanced, metal flow increased, but its strain field non-uniformly distributed, metal flow and plastic deformation would be strengthen by increase pass reduction, and the lateral broadening in the head is bigger than that in the tail.


2010 ◽  
Vol 450 ◽  
pp. 87-90
Author(s):  
Qin Qin ◽  
Di Ping Wu ◽  
Jing Jing Li ◽  
Yong Zang

Due to the complexity of H-beam’s cross section, it is difficult to calculate the rolling force and force torque accurately using classic formulas conveniently when H-beams of new size are developed. This paper describes an investigation into the reversing process of H-beam using MARC software and compares the results with rolling data from the production line. A FEM model involving in three-dimensional, elastic-plastic and thermo-mechanical coupling has been established successfully to predict multi-pass rolling process. The analysis produces outputs such as deformation rules, rolling force and the web thickening. The influence of rolling reduction, the reduction rate between the web and flange are also discussed. The indications are that there is much difference between the measurement of rolling force and the rolling force calculated by using classic formulas. The reason is that real reduction during rolling process is much more than the scheduled one. A new revised method was suggested to calculate the rolling force. The simulation results show that this new method for calculating rolling force is feasible.


2020 ◽  
Vol 2 (12) ◽  
Author(s):  
Yu-Feng Zhang ◽  
Hong-Shuang Di ◽  
Xu Li ◽  
Wen Peng ◽  
De-Wen Zhao ◽  
...  

1995 ◽  
Vol 117 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Zone-Ching Lin ◽  
Y. C. Cheng

The paper is an investigation of strip curvature caused by the different speeds between the upper work roll and the lower work roll in the rolling process for an aluminum strip. At the same time, we analyzed the variations in the temperature field and strain field, and used a method of speeds variation of the upper and lower work rolls to calibrate the deformation curvature caused by the coolant condition in the hot rolling process. Based on the large deformation-large strain theory, and by means of the Updated Lagrangean Formulation (ULF) and increment theory, a coupled thermoelastic-plastic analysis model for hot rolling process is thus constructed. At the same time the finite difference method was also used to solve the transient heat transfer equation. Finally, the numerical analysis method developed in this study was employed to analyze the changes in the aluminum strip’s temperature and other changes during rolling. In addition, the average rolling force obtained from the simulation was compared with that from the experiments. It verified that the model in this study is reasonable.


Author(s):  
JG Ding ◽  
HY Wang ◽  
DH Zhang ◽  
DW Zhao

In this paper, three-dimensional velocity field is proposed by means of stream function method with bisecting yield criterion in chamfer edge rolling of ultra-heavy plate. Parabolic dog-bone shape function is derived so as to obtain velocity field with fixed angle of chamfer edge by stream function method, dog-bone shape coefficient η can be derived from volume invariant condition, and then the plastic deformation power, shear power as well as friction power are obtained respectively with the bisecting yield criterion. Summing up the power contributions, total power functional is presented, from which minimum value can be obtained by searching method, and vertical rolling force and torque are also finally obtained. The predictions of roll force and torque are compared with different angles of chamfer edge as well as different plate thicknesses. The results are shown to be in a very good agreement with the analytical and experimental results.


2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Lei He ◽  
Ruijie Ruan ◽  
Chen Lin ◽  
Ting Dai ◽  
Xianjun Hu ◽  
...  

The microstructures and mechanical properties of a low-carbon steel, hot-rolled by a six-pass dynamic strain-induced transformation (DSIT) process, with different start rolling temperatures, are studied by combining experiments and finite element simulations. The start rolling temperatures of the last three passes are about 10°C higher and 20°C lower than theAr3temperature, for Processes 1 and 2, respectively. The results show that as the rolling process proceeds, rolling forces increase, while slab temperatures decrease. Before starting Pass 4, the temperature of the slab center is higher than that of the slab surface. During Pass 4 to Pass 6, however, the temperatures of the slab center and surface are nearly identical but fluctuate remarkably due to the large reduction rate. The simulated maximum rolling force and start rolling temperature of each pass agree reasonably with the experimental measurements. It is found that the simulated start temperatures of the slab center in the last three passes are about 5~25°C higher than theAr3temperature for Process 1, and the DSIT condition is better satisfied for Process 2. As a result, Process 2 produces finer grain sizes and higher yield strengths than Process 1.


2021 ◽  
Author(s):  
Yufeng Zhang ◽  
Meiying Zhao ◽  
Li Xu ◽  
Hong Shuang Di ◽  
Xiaojuan Zhou ◽  
...  

Abstract Vertical rolling is an important technique to control the width of continuous casting slab in hot rolling field. Accurate prediction of vertical rolling force is a core point to maintain rolling mill equipment. Due to the limitation of the algorithm, the prediction accuracy of most vertical rolling force models based on the energy method can only reach more than 10%. Therefore, it is challenging to optimize the rolling force model to improve the prediction accuracy. This paper presents an innovative approach for optimizing the calculation of vertical rolling force with a unified yield criterion. Firstly, the maximal width of dog bone region is determined by the slip-line method and described the dog bone shape via sine function model. Furthermore, proposed velocity and corresponding strain rate fields satisfy kinematically admissible condition is used to calculate the total power. Finally, the analytical solution of the rolling force and dog bone shape model is obtained by repeatedly optimizing the weighted coefficient b of intermediate principal shear stress on the yield criterion. And the effectiveness of the proposed mechanical model is verified by measured data in strip hot rolling field and other models’ results. The results shows that the prediction accuracy of vertical rolling force model can be improved by optimizing the value of b. Then, the impacts of reduction rate, initial thickness and friction factor on dog-bone shape size and vertical rolling force are discussed.


2011 ◽  
Vol 189-193 ◽  
pp. 1991-1996 ◽  
Author(s):  
Xiu Mei Zhou ◽  
Lin Hua ◽  
Dong Sheng Qian

Special rolling is also called rotary forming process, which is an advanced manufacture technology of making workpiece generate deformation in a rotary state by continuous local plastic forming. Disk rotary parts with outer stepped cross-section, such as wheels, flanges, valves and so on, are widely used in engineering machinery. Traditionally, this kind of part is manufactured by forging and cutting, which consumes a lot of energy and materials especially to the large size part. In this paper, a new specific rolling technique called three rolls cross rolling is first presented to produce this kind of part, and the principle and characteristics of this technique are described in detail. Then, base on the principle of the three rolls cross rolling, a 3D coupled thermo-mechanical FE model is developed under ABAQUS software environment. As a result, under the simulation and analyses of a real example, the feasibility of this technique is verified, and the evolutional laws of the strain, temperature and rolling force and power parameters during the process are investigated as well. The obtained results provide valuable guidelines for the further investigation on the forming characteristic of the three rolls cross rolling technique.


2014 ◽  
Vol 536-537 ◽  
pp. 1460-1463
Author(s):  
Zhao Wei Dong ◽  
Xiao Hang Wan ◽  
Zhan Ping Huang ◽  
Sheng Yong Liu

In order to increase rolling efficiency and production quality, adopted the finite element method, the rolling force analysis model of 3500mm rolling mill is established in this paper based on the thermal mechanical analysis theory, According to the rolling technology parameters in actual production, the rolling process of plate rolling is systematic studied, which thinks about the thermal stress caused by uneven temperature distribution. The law of technology parameters influencing rolling force is gained, which uses in the optimization of rolling process, improves production efficiency. it has important significance to reduce the energy consumption.


2020 ◽  
Vol 14 ◽  
Author(s):  
Xiao-bin Fan ◽  
Hao Li ◽  
Yu Jiang ◽  
Bing-xu Fan ◽  
Liang-jing Li

Background: Rolling mill vibration mechanism is very complex, and people haven't found a satisfactory vibration control method. Rolling interface is one of the vibration sources of the rolling mill system, and its friction and lubrication state has a great impact on the vibration of the rolling mill system. It is necessary to establish an accurate friction model for unsteady lubrication process of roll gap and a nonlinear vibration dynamic model for rolling process. In addition, it is necessary to obtain more direct and real rolling mill vibration characteristics from the measured vibration signals, and then study the vibration suppression method and design the vibration suppression device. Methods: This paper summarizes the friction lubrication characteristics of rolling interface and its influence on rolling mill vibration, as well as the dynamic friction model of rolling interface, the tribological model of unsteady lubrication process of roll gap, the non-linear vibration dynamic model of rolling process, the random and non-stationary dynamic behavior of rolling mill vibration, etc. At the same time, the research status of rolling mill vibration testing technology and vibration suppression methods were summarized. Time-frequency analysis of non-stationary vibration signals was reviewed, such as wavelet transform, Wigner-Ville distribution, empirical mode decomposition, blind source signal extraction, rolling vibration suppression equipment development. Results: The lubrication interface of the roller gap under vibration state presents unsteady dynamic characteristics. The signals generated by the vibration must be analyzed in time and frequency simultaneously. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. When designing or upgrading the mill structure, it is necessary to optimize the structure of the work roll bending and roll shifting system, such as designing and developing the automatic adjustment mechanism of the gap between the roller bearing seat and the mill stand, adding floating support device to the drum shaped toothed joint shaft, etc. In terms of rolling technology, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, reducing rolling force of vibration prone rolling mill, increasing entrance temperature, reducing rolling inlet tension, reducing strip outlet temperature and reasonably arranging roll diameter. The coupling vibration can also be suppressed by optimizing the hydraulic servo system and the frequency conversion control of the motor. Conclusion: Under the vibration state, the lubrication interface of roll gap presents unsteady dynamic characteristics. The signal generated by vibration must be analyzed by time-frequency distribution. In the aspect of vibration suppression of rolling mill, the calculation of inherent characteristics should be carried out in the design of rolling mill to avoid dynamic defects such as resonance. It is necessary to optimize the structure of work roll bending and roll shifting system when designing or reforming the mill structure. In rolling process, rolling vibration can be restrained by improving roll lubrication, reasonably distributing rolling force of each rolling mill, increasing billet temperature, reasonably arranging roll diameter and reducing rolling inlet tension. Through the optimization of the hydraulic servo system and the frequency conversion control of the motor, the coupling vibration can be suppressed. The paper has important reference significance for vibration suppression of continuous rolling mill and efficient production of high quality strip products.


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