Inhomogeneity of temperature distribution through thickness of the aluminium strip during hot rolling

2011 ◽  
Vol 225 (12) ◽  
pp. 2938-2952 ◽  
Author(s):  
H R Rezaei Ashtiani ◽  
H Bisadi ◽  
M H Parsa
Keyword(s):  
Temperature Distribution ◽  
Hot Rolling ◽  
Work Roll ◽  
Three Dimensions ◽  
Temperature Fields ◽  
Temperature History ◽  
Rolled Strip ◽  
Fe Model ◽  
Temperature Inhomogeneity ◽  
Roll Temperature

Temperature distribution and inhomogeneity of its through thickness of the strip play an essential role in hot rolling processes, where both the strip and work-roll behaviour are affected strongly by these temperature fields and the microstructural and mechanical properties through thickness of hot rolled strip depend on this temperature inhomogeneity within the strip being deformed during hot rolling. In this investigation, a mathematical model was developed to predict the thermal history and inhomogeneity of temperature through thickness of an aluminium alloy strip undergoing single-stand hot plate rolling using the commercial finite element (FE) package, ABAQUS/Explicit in three dimensions. To estimate the reliability of the numerical analysis, the FE model was validated using experimental roll force and torque data and also temperature history at the centre-line of strip; good agreement was found between the two sets of predicated and experimental results. The effects of various process parameters, such as rolling speed, interface heat-transfer and friction coefficients between strip and work roll, initial thickness of the strip, and work-roll temperature and diameter on the temperature inhomogeneity, is considered.

scholarly journals Simulation of Thermal Stress and Fatigue Life Prediction of High Speed Steel Work Roll during Hot Rolling Considering the Initial Residual Stress

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 966 ◽  
Author(s):  
Kejun Hu ◽  
Fuxian Zhu ◽  
Jufang Chen ◽  
Nao-Aki Noda ◽  
Wenqin Han ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Stress ◽  
Fatigue Life ◽  
Hot Rolling ◽  
Work Roll ◽  
Roll Surface ◽  
Initial Residual Stress ◽  
Thermal Fatigue Life ◽  
Cooling Conditions ◽  
Roll Temperature

Considerable residual stress is produced during heat treatment. Compressive residual stress at the shell is conductive to improving the thermal fatigue life of a work roll, while tensile stress in the core could cause thermal breakage. In hot rolling, thermal stress occurs under the heating-cooling cycles over the roll surface due to the contact with the hot strip and water spray cooling. The combination of thermal stress and residual stress remarkably influences the life of a work roll. In this paper, finite element method (FEM) simulation of hot rolling is performed by treating the residual stress as the initial stress. Afterwards, the effects of the initial roll temperature and cooling conditions on thermal stress considering the initial residual stress are discussed. Lastly, the thermal fatigue life of a work roll is estimated based on the strain life model. The higher initial roll temperature causes a higher temperature but a lower compressive thermal stress at the roll surface. The surface temperature and compressive stress increase significantly in the insufficient cooling conditions, as well as the center tensile stress. The calculation of the fatigue life of a work roll based on the universal slopes model according to the 10% rule and 20% rule is reasonable compared with experimental results.

FE Analysis of Hot Strips’ Temperature Distribution in Laminar Cooling Process

2014 ◽  
Vol 900 ◽  
pp. 647-650
Author(s):  
Yu Qing Zheng ◽  
Jing Yu Cui
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Rolled Strip ◽  
Fe Model ◽  
Laminar Cooling ◽  
Cooling Process ◽  
Transfer Coefficients ◽  
Position Effects ◽  
Simulation Accuracy ◽  
Hot Rolled

The temperature distribution of the hot-rolled strip in the ROT cooling process was calculated and analyzed using ABAQUS in this paper. The complicated heat transfer coefficients of hot strip considering the position effects of top and bottom nozzles, and the non-uniform heat transfer situation along the width direction were defined by user subroutine. The simulation results were in good correlation with test results. It’s helpful for further analysis to improve the temperature distribution uniformity and the simulation accuracy for FE model, and guide the on-site production.

Analysis of Casting Roll Temperature Distribution and Thermal Deformation in Twin-Roll Continuous Strip Casting

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Guangming Zhu ◽  
Yuwen Zhang
Keyword(s):  
Temperature Distribution ◽  
Thermal Deformation ◽  
Cooling Water ◽  
Processing Parameters ◽  
Strip Casting ◽  
Fe Model ◽  
Roll Temperature ◽  
Shrink Fit ◽  
Twin Roll ◽  
Continuous Strip

In twin-roll continuous strip casting, casting roll is heated by molten metal, and thermal deformation is caused to change strip thickness and quality. It is imperative to understand casting roll temperature distribution and thermal deformation. In this paper, a 2D finite element (FE) model is built to analyze casting roll temperature and thermal deformation under various casting processing parameters. The influences of shrink fit of roll sleeve and shaft are taken into account and the coating was treated to be consistent to the actual situation. The results show that casting temperature fluctuates cyclically within a thin top layer in stable casting, and there is almost no temperature fluctuation near cooling water holes.

Numerical Simulation and Experiment Research on Temperature Field of Steel Slab in Walking Beam Furnace

2011 ◽  
Vol 704-705 ◽  
pp. 412-418 ◽  
Author(s):  
Chao Chen ◽  
Cui Jiao Ding ◽  
De Gang Ouyang ◽  
Zhan Zeng Liu ◽  
Zhong Hua Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Temperature Fields ◽  
Temperature History ◽  
Experiment Research ◽  
Steel Slab ◽  
History Of ◽  
Simulation And Experiment ◽  
Heating Up

This paper presents a study of the temperature fields of steel slab in a walking beam furnace. To simulate the temperature distribution in the slab of heating-up process in heating furnace, a two-dimensional mathematical model was developed. The heat transfer in the furnace was very complex, so the model was developed on the assumptions that the temperature of each section of the furnace was unchangeable, the slab moved in the furnace in even velocity, the heat transfer between the slab and the walking beam was out of consideration, the longitudinal heat conduction of the slab and the effect of the scale on the heat conduction were neglected. The equations were calculated by the finite difference method. A black box experiment research was carried out to measure the temperature history of the slab as it passed through the furnace. The comparison of the calculated results with the measured results showed that the model worked well for simulating the temperature distribution of the slab in walking beam furnace. With this developed model, the optimizing of hot rolling and heating processes of steel slab can be investigated in the future.

Effect of Rolling Speed on Instantaneous Temperature Distribution and Thermal Expansion of Work Roll in Hot Strip Rolling

2011 ◽  
Vol 338 ◽  
pp. 576-580
Author(s):  
Gui Jie Zhang ◽  
Ying Zi Wang ◽  
Kang Li
Keyword(s):  
Thermal Expansion ◽  
Temperature Distribution ◽  
Work Roll ◽  
Rolling Speed ◽  
Hot Strip Rolling ◽  
Strip Rolling ◽  
Rolling Parameter ◽  
Roll Temperature ◽  
Profile Control ◽  
Instantaneous Temperature

In the unsteady state, work roll temperature distribution and thermal expansion have an enormous effect on the process of hot rolling. The rolling speed in the finish rolling as an important rolling parameter plays a crucial role of obtaining the optimum temperature distribution and thermal expansion. Using the finite element method, it solves the regularity of temperature distribution and thermal expansion with thermal-structural coupling analysis, which provide theoretic proof of optimizing gauge and profile control.

scholarly journals Thermal Camber and Temperature Evolution on Work Roll during Aluminum Hot Rolling

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1434
Author(s):  
Evangelos Gavalas ◽  
Spyros Papaefthymiou
Keyword(s):  
Steady State ◽  
Process Parameters ◽  
Hot Rolling ◽  
Work Roll ◽  
Temperature Evolution ◽  
Entry And Exit ◽  
Cooling Strategy ◽  
Roll Temperature ◽  
Significant Difference ◽  
Geometric Variation

Flatness is an important quality characteristic for rolled products. Modern hot rolling mills are equipped with actuators that can modify the uneven thickness distribution across the width of the strip (crown), taking into account online measurements of various process parameters such as temperature, force and exit strip profile, either automatically or manually by the operator. However, the crown is also influenced by many parameters that cannot easily be measured during production, such as work roll temperature evolution through thickness and roll geometric variation due to thermal expansion (thermal camber). These have an impact on the strip flatness. In this paper, a thermo-mechanical finite element model on LS-DYNA™ software was utilized to predict the influence of process parameters, and more specifically strip temperature, cooling strategy (application of cooling on the entry or entry and exit side simultaneously) and roll core temperature, on the evolution of roll temperature and thermal camber. The model was initially validated with industrial data. The results indicate that the application of both entry and exit cooling is ~30% more efficient compared to the entry cooling only, thus the thermal camber will be reduced by 2 μm. A hotter roll (380 K) is more stable compared to the cold roll (340 K), showing also an improvement of 2 μm. The hotter roll will also reach a thermal steady state on the surface faster compared to the colder one, without making a significant difference on the steady state temperature. Strip temperature plays a roll in the thermal camber evolution, but it is a less important parameter compared to cooling strategy and roll temperature.

Boundary Condition Design to Heat a Moving Object at Uniform Transient Temperature Using Inverse Formulation

2004 ◽  
Vol 126 (3) ◽  
pp. 619-626 ◽  
Author(s):  
Hakan Ertu¨rk ◽  
Ofodike A. Ezekoye ◽  
John R. Howell
Keyword(s):  
Boundary Condition ◽  
Temperature Distribution ◽  
Design Problem ◽  
Manufacturing Industry ◽  
Three Dimensional ◽  
Chemical Deposition ◽  
Iterative Solution ◽  
Conveyor Belt ◽  
Temperature History ◽  
Transient Temperature

The boundary condition design of a three-dimensional furnace that heats an object moving along a conveyor belt of an assembly line is considered. A furnace of this type can be used by the manufacturing industry for applications such as industrial baking, curing of paint, annealing or manufacturing through chemical deposition. The object that is to be heated moves along the furnace as it is heated following a specified temperature history. The spatial temperature distribution on the object is kept isothermal through the whole process. The temperature distribution of the heaters of the furnace should be changed as the object moves so that the specified temperature history can be satisfied. The design problem is transient where a series of inverse problems are solved. The process furnace considered is in the shape of a rectangular tunnel where the heaters are located on the top and the design object moves along the bottom. The inverse design approach is used for the solution, which is advantageous over a traditional trial-and-error solution where an iterative solution is required for every position as the object moves. The inverse formulation of the design problem is ill-posed and involves a set of Fredholm equations of the first kind. The use of advanced solvers that are able to regularize the resulting system is essential. These include the conjugate gradient method, the truncated singular value decomposition or Tikhonov regularization, rather than an ordinary solver, like Gauss-Seidel or Gauss elimination.

Modelling the Temperature Distribution along the Length of Strip during Hot Rolling Process

2004 ◽  
Vol 75 (5) ◽  
pp. 330-338 ◽  
Author(s):  
Xiaochun Sha ◽  
Dianzhong Li ◽  
Yongjun Lan ◽  
Xiaogang Zhang ◽  
Yiyi Li
Keyword(s):  
Temperature Distribution ◽  
Hot Rolling ◽  
Rolling Process ◽  
Hot Rolling Process
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