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.

Numerical Evaluation of a High Speed Steel Work Roll during Hot Strip Rolling Process

2017 ◽  
Vol 904 ◽  
pp. 55-60 ◽  
Author(s):  
Guan Yu Deng ◽  
Hong Tao Zhu ◽  
A. Kiet Tieu ◽  
Qiang Zhu ◽  
Li Hong Su ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Speed ◽  
Initial Temperature ◽  
High Speed Steel ◽  
Work Roll ◽  
Rolling Process ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Steel Work ◽  
Hot Strip

Hot strip rolling process is one of the most promising industrial processes to fabricate finished or semi-finished bulk products. Numerical analysis on the temperature and thermal stress distributions in a high speed steel work roll during hot rolling has been conducted based on a transient thermo-mechanical model. Influence of initial work roll body temperature on temperature and thermal stress has been discussed in detail by assuming different rolling stages. Compared to the work roll surface, stress is much smaller at depth of 2.1 mm and 5.0 mm, respectively. Results showed similar maximum circumferential thermal stress at both depths of 2.1 mm and 5.0 mm when the roll has initial temperature of 25 °C and 100 °C, but they are about 3 times and 8 times larger than at depth of 2.1 mm and 5.0 mm, respectively, when the initial temperature is 200 °C.

Simulation of Thermal Phenomena in Reverse Strip-Rolling Process

2018 ◽  
Vol 941 ◽  
pp. 1424-1430
Author(s):  
Alexander Nam ◽  
Uwe Prüfert ◽  
Marciej Pietrzyk ◽  
Rudolf Kawalla ◽  
Ulrich Prahl
Keyword(s):  
Hot Rolling ◽  
Rolling Process ◽  
Temperature Model ◽  
Hot Strip Rolling ◽  
Forming Process ◽  
Strip Rolling ◽  
Unknown Parameters ◽  
Hot Strip ◽  
Thermal Phenomena ◽  
Good Agreement

In the reverse hot strip rolling, the coiling and uncoiling of the strip leads to unstable conditions during the forming process. Both the temperature of the strip and the dwell time in the coil vary and influence the microstructure evolution passing in the coil during reverse rolling. It makes the design of this process difficult. Therefore, development of the temperature model for the reverse hot rolling including coiling and uncoiling was the main objective of the paper. The identification of the unknown parameters of the boundary conditions is proposed. Methods for their determination are discussed. The analysis is performed on example of the reverse hot rolling of the magnesium alloy AZ31. The resulting temperature model reveals good agreement with thermocouple and pyrometer measurements.

Computational Model of Work Roll Temperature Distribution during Hot Strip Rolling Process

2012 ◽  
Vol 229-231 ◽  
pp. 2432-2435
Author(s):  
Xing Dong Li ◽  
Yan Xia Shan ◽  
Chang Hong Guo
Keyword(s):  
Computational Models ◽  
Work Roll ◽  
Rolling Process ◽  
Hot Strip Mill ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Roll Temperature ◽  
Hot Strip ◽  
Temperature Field Model ◽  
Deformation Work

Computational models of deformation and friction work were established by dividing contact arc between strip and work roll into two sliding regions, two braking regions and one stagnating region. A two dimensional temperature field model of work roll was established by finite difference method according to practical boundary conditions. Simulation results show that with the increase of rolling pass, deformation work reduced while friction work increased, except that deformation and friction works at the last pass were the least. The computed rolling forces and work roll surface temperatures agree well with measured values collected from a hot strip mill.

Determining the No-Recrystallization Conditions for Industrial Hot Strip Rolling of Steels Using Laboratory Simulations

2012 ◽  
Vol 706-709 ◽  
pp. 1409-1414 ◽  
Author(s):  
Gwenola Herman ◽  
Evgueni I. Poliak
Keyword(s):  
Hot Rolling ◽  
Incubation Time ◽  
Rolling Process ◽  
Critical Conditions ◽  
Recrystallization Temperature ◽  
Static Case ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Hot Strip ◽  
Cold Rolling And Annealing

Avoiding recrystallization of austenite in hot strip rolling of steels is highly important for enhancing mechanical properties of hot rolled products, as well as for the products undergoing cold rolling and annealing or coating. Recrystallization can only be avoided if its incubation time is longer that the time intervals characteristic for a particular hot rolling process. The present work focuses on computation of incubation time tinc for static recrystallization using laboratory hot deformation data and on extrapolation the results to industrial conditions. The computations are done based on application of critical conditions for initiation of dynamic recrystallization to the static case. No-recrystallization temperature in hot strip rolling is determined by setting tinc equal to interpass time. Simulations allow for prediction of the onset of austenite static or metadynamic recrystallization after individual rolling passes during industrial hot rolling and evaluation of the effects of strip thickness, rolling speeds, etc.

scholarly journals Prediction of Bending Force in the Hot Strip Rolling Process Using Multilayer Extreme Learning Machine

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yan Wu ◽  
Hongchao Ni ◽  
Xu Li ◽  
Feng Luan ◽  
Yaodong He
Keyword(s):  
Extreme Learning Machine ◽  
Hot Rolling ◽  
Absolute Error ◽  
Rolling Process ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Bending Force ◽  
Hot Strip ◽  
Learning Machine ◽  
Hidden Layer

In the hot strip rolling process, accurate prediction of bending force can improve the control accuracy of the strip flatness and further improve the quality of the strip. In this paper, based on the production data of 1300 pieces of strip collected from a hot rolling factory, a series of bending force prediction models based on an extreme learning machine (ELM) are proposed. To acquire the optimal model, the parameter settings of the models were investigated, including hidden layer nodes, activation function, population size, crossover probability, and hidden layer structure. Four models are established, one hidden layer ELM model, an optimized ELM model (GAELM) by genetic algorithm (GA), an optimized ELM model (SGELM) by hybrid simulated annealing (SA) and GA, and two-hidden layer optimized ELM model (SGITELM) optimized by SA and GA. The prediction performance is evaluated from the mean absolute error (MAE), root-mean-squared error (RMSE), and mean absolute percentage error (MAPE). The results show that the SGITELM has the highest prediction accuracy in the four models. The RMSE of the proposed SGITELM is 11.2678 kN, and 98.72% of the prediction data have an absolute error of less than 25 kN. This indicates that the proposed SGITELM with strong learning ability and generalization performance can be well applied to hot rolling production.

Finite Element Analysis of Temperature and Crown of Rolls in Hot Strip Rolling

2009 ◽  
Vol 16-19 ◽  
pp. 575-579 ◽  
Author(s):  
Da Le Sun ◽  
Jian Guo Zhao ◽  
Liang Yu Chen
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Work Roll ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Element Analysis ◽  
Rolling Mills ◽  
Hot Strip ◽  
Thermal Crown ◽  
Work Rolls

In this paper a three-dimensional numerical computation on temperature and crown of rolls in hot strip rolling was evaluated based on finite element method and parallel computation technology with multiple CPUs. A comparison between calculated results and actual data collected from rolling mills was presented, which indicated the high accuracy of the model. The calculated results indicated that a significant impact in thin layer of work roll surface was brought by thermal load, while much weaker in the core. Furthermore, the temperature field and thermal crown of hot mill work rolls would reach a stabilized condition only when several rolling cycle be finished.

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