Two-Dimensional Transient Thermal Behavior of Work Rolls in Rolling Process

1998 ◽  
Vol 120 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Remn-Min Guo
Keyword(s):  
Boundary Conditions ◽  
Complete Solution ◽  
Work Roll ◽  
Rolling Process ◽  
Related Individual ◽  
Various Boundary Conditions ◽  
Cooling Behavior ◽  
Friction Energy ◽  
Transient Thermal ◽  
Work Rolls

In the rolling process, deformation and friction energy generated in the roll bite transfer to work rolls. Work rolls are cooled by the cooling medium in both entry and exit sides of the mill. The transient cooling behavior of the roll affects the temperature distribution and the thermal profile. This article proposes a semi-analytical solution to solve the temperature field of the work roll which is subjected to various cooling and heating boundary conditions during a rolling campaign. Laplace and inverse transforms are applied to pursue the unsteady solution for one particular boundary condition. The complete solution for various boundary conditions is superimposed by related individual solutions using Duhamel’s rule. Case studies as demonstrated in this paper show versatility of the developed model.

Finite Element Analysis of Transient Thermal Problems of Work Rolls in Hot Rolling Process

1999 ◽  
Author(s):  
James D. Lee ◽  
Majid T. Manzari ◽  
Yin-Lin Shen ◽  
Wenjun Zeng
Keyword(s):  
Finite Element ◽  
Hot Rolling ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Rolling Process ◽  
Thermal Problem ◽  
Element Analysis ◽  
Hot Rolling Process ◽  
Transient Thermal ◽  
Work Rolls

Abstract The three-dimensional transient thermal problem of work rolls in the entire hot rolling process has been formulated. It includes the time-varying boundary conditions specified at the roll surface taking the schedule of both rolling and idling cycles into consideration. The corresponding finite element equations are derived and solved by the Runge-Kutta-Verner method. The finite element solutions indicate that the temperature variations in the circumferential direction are overwhelming. Case studies unveil the thermal characteristics of the work rolls in various kinds of mill operations. Numerical results are presented and compared with Guo’s analytical solutions.

Determination of Thermal Parameters of a Work-Roll in Warm Rolling Using Inverse Modeling

2018 ◽  
Author(s):  
Vinod Yadav
Keyword(s):  
Inverse Method ◽  
Work Roll ◽  
Rolling Process ◽  
Thermal Parameters ◽  
Shop Floor ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Convective Heat Transfer Coefficients ◽  
Work Rolls

Thermal parameters of a work-roll play an important role in the modeling of the rolling process, due to periodic thermal loading. The knowledge of thermal parameters is also vital in understanding the fatigue life of the work-roll and the thermal crown. However, estimation of the thermal parameters viz., thermal conductivity, thermal diffusivity and convective heat transfer coefficients at both, inner and outer roll periphery is tough to realize during the rolling process. Various methods employed earlier for measuring the thermal properties of work-rolls in the rolling process requires intrusion in the surface of the work-rolls, mainly to embed the thermocouples inside the rolls. These methods are easy to implement, but it is really hard to achieve truthful estimation. A possible way out is to measure the average thermal parameters of a work roll in the rolling process by utilizing the measured temperature at two specified locations on the work-roll surface. In this work, an inverse method is proposed to estimate the thermal properties and convective heat transfer coefficients of a roll in the rolling process. The inverse method makes use of a direct model of temperature determination considering plane strain problem, which is based on the integral transform method. For minimizing the error between the computed and experimentally recorded data, a quasi-Newton method is used. In lieu of shop floor experiments, a finite element method (FEM) based package ABAQUS 6.10 is used to obtain the temperature distribution in the work-roll. Further, an additive white Gaussian error is added in the FEM simulated measurements to assess the inverse method for stability towards mild measurements. The inverse estimation is successfully validated and can be used in shop floor for the online determination of thermal parameters of the work-rolls in the rolling process.

scholarly journals Thermal impedance estimations by semi-derivatives and semi-integrals: 1-D semi-infinite cases

2013 ◽  
Vol 17 (2) ◽  
pp. 581-589 ◽  
Author(s):  
Jordan Hristov ◽  
Ganaoui El
Keyword(s):  
Heat Conduction ◽  
Fractional Calculus ◽  
Boundary Conditions ◽  
Half Time ◽  
Thermal Impedance ◽  
Entire Domain ◽  
Various Boundary Conditions ◽  
Transient Thermal

Simple 1-D semi-infinite heat conduction problems enable to demonstrate the potential of the fractional calculus in determination of transient thermal impedances under various boundary conditions imposed at the interface (x=0). The approach is purely analytic and very effective because it uses only simple semi-derivatives (half-time) and semi-integrals and avoids development of entire domain solutions. 0x=

An Investigation of the Effect of Speeds of Work Rolls on Rolling Strip

1995 ◽  
Vol 117 (3) ◽  
pp. 341-346 ◽  
Author(s):  
Zone-Ching Lin ◽  
Y. C. Cheng
Keyword(s):  
Hot Rolling ◽  
Rolling Force ◽  
Large Strain ◽  
Work Roll ◽  
Rolling Process ◽  
Analysis Model ◽  
Hot Rolling Process ◽  
Rolling Strip ◽  
Work Rolls ◽  
Thermoelastic Plastic

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.

Stochastic Method to Predict Effects of Roll Grinding Deviations on Sheet Flatness in Cold Rolling

2021 ◽  
pp. 1-34
Author(s):  
Feng Zhang ◽  
Arif S Malik
Keyword(s):  
Random Field ◽  
Contact Region ◽  
Measurement Data ◽  
Work Roll ◽  
Rolling Process ◽  
Rolled Sheet ◽  
Field Problem ◽  
Sheet Rolling ◽  
Roll Axis ◽  
Work Rolls

Abstract Industrial measurements of the diameter profiles of work-rolls used in cold sheet rolling are applied with a stochastic roll-stack model to better understand how residual error from the roll grinding process affects the rolled sheet flatness quality. Roll diameter measurements taken via a non-contact, optical device on new, warm, and worn work-rolls show that the diameter deviations vary along the roll lengths, across roll samples, and at different operational states, suggesting a multi-dimensional random field problem. Studies are conducted for a 4-high rolling mill with 301 stainless steel sheet to investigate the reliability in achieving target flatness considering the work-roll diameter random field. Also investigated is the sensitivity of the flatness reliability to roll diameter deviations at different locations along the roll lengths, and for the three operational states (newly machined, warm, and worn following several passes). The results lead to several key findings. Foremost, it is shown that an assumption of statistical independence among the residual grinding errors at different roll axis locations is improper. Further, it is demonstrated that, for the measured grinding error correlation patterns, the roll diameter deviations external to the roll/sheet contact region play an important role in contributing to flatness defects within the sheet, and that these influences vary according to the roll operational state (new, warm, worn). The presented stochastic model and applied measurement data thus provide for a new understanding into how roll grinding performance influences dimensional quality in the sheet rolling process.

scholarly journals On the Evolution of Temperature and Combined Stress in a Work Roll under Cyclic Thermo-Mechanical Loadings during Hot Strip Rolling and Idling

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5054
Author(s):  
Kejun Hu ◽  
Qinghe Shi ◽  
Wenqin Han ◽  
Fuxian Zhu ◽  
Jufang Chen
Keyword(s):  
Thermal Stress ◽  
Hot Rolling ◽  
Work Roll ◽  
Rolling Process ◽  
Roll Surface ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Hot Strip ◽  
Calculation Results ◽  
Work Rolls

An accurate prediction of temperature and stress evolution in work rolls is crucial to assess the service life of the work roll. In this paper, a finite element method (FEM) model with a deformable work roll and a meshed, rigid body considering complex thermal boundary conditions over the roll surface is proposed to assess the temperature and the thermal stress in work rolls during hot rolling and subsequent idling. After that, work rolls affected by the combined action of temperature gradient and rolling pressure are investigated by taking account of the hot strip. The accuracy of the proposed model is verified through comparison with the calculation results obtained from the mathematical model. The results show that thermal stress is dominant in the bite region of work rolls during hot rolling. Afterwards, the heat treatment residual stresses which are related to thermal fatigue are simulated and introduced into the work roll as the initial stress to evaluate the redistribution under the thermal cyclic loads during the hot rolling process. Results show that the residual stress significantly changed near the roll surface.

A Study on Corrosion Wear of Cold Rolling Work Roll

2013 ◽  
Vol 871 ◽  
pp. 152-158
Author(s):  
Wei Hua Sun ◽  
Hong Chun Li ◽  
Ahn Kiet Tieu
Keyword(s):  
Cold Rolling ◽  
Corrosive Wear ◽  
Work Roll ◽  
Rolling Process ◽  
Corrosion Wear ◽  
Roll Surface ◽  
Steel Rolling ◽  
Conductive Medium ◽  
Materials Used ◽  
Work Rolls

The MMS-2B wear machine was used to study abrasion wear of work rolls in cold rolling by simulating emulsion cooling during the cold rolling process. The work roll materials used were 4%Cr, same as those in industrial production. The surface SEM scanning photographs were taken every 30 minutes until the friction experiment finished, and erosive appearance of emulsion on the work roll surface could be seen in the photos. The corrosive wear of the work roll surface is discussed. Findings show that the main causes of stress corrosion and pitting corrosion are uneven microstructure on the work roll surface and a large number of dislocation accumulations, which form microscopic cells. Water in steel rolling emulsion is the main conductive medium of electrochemistry reaction, and this intensifies the corrosive wear.

A Finite Element Approach to Transient Thermal Analysis of Work Rolls in Rolling Process

2000 ◽  
Vol 122 (4) ◽  
pp. 706-716 ◽  
Author(s):  
James D. Lee ◽  
Majid T. Manzari ◽  
Yin-Lin Shen ◽  
Wenjun Zeng
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Thermal Characteristics ◽  
Rolling Process ◽  
Time Varying ◽  
Thermal Problem ◽  
Temperature Variations ◽  
Element Approach ◽  
Transient Thermal ◽  
Work Rolls

The three-dimensional transient thermal problem of work rolls in the entire rolling process has been formulated. It includes the time-varying boundary conditions specified at the roll surface taking the schedule of both rolling and idling cycles into consideration. The corresponding finite element equations are derived and solved by the Runge-Kutta-Verner method. The finite element solutions indicate that the temperature variations in the circumferential direction are overwhelming. Case studies unveil the thermal characteristics of the work rolls in various kinds of mill operations. The effects of the specific heat and the angular velocity of the work rolls are presented. Numerical results are compared with Guo’s analytical solutions. [S1087-1357(00)01604-X]

Upon Impact Numerical Modeling of Foam Materials

2017 ◽  
Vol 54 (2) ◽  
pp. 195-202
Author(s):  
Vasile Nastasescu ◽  
Silvia Marzavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Boundary Conditions ◽  
General Character ◽  
Foam Material ◽  
Various Boundary Conditions ◽  
Specific Behaviour

The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

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