scholarly journals Influence of snake rolling on metal flow in hot rolling of aluminum alloy thick plate

2020 ◽  
Vol 21 (5) ◽  
pp. 525
Author(s):  
Pujun Hao ◽  
Jingna Liu

Most asymmetrical rolling conditions should not appear in regular rolling processes, but for obtaining large deformations inside aluminium alloy thick plates, the asymmetrical rolling process is the most effective method. Snake rolling is adopted for promoting more deformation inside the plates. For exploring the deformation inside an aluminium alloy thick plate, a finite element model for simulating the process of snake rolling is established and the key influence factors are set as initial thickness, speed ratio and offset distance. The results show that deformation inside of the plate increases obviously while the thickness of plate is less than 300 mm after snake rolling. The speed ratio has a positive effect on promoting deformation partly inside of the plate. On the contrary, the offset distance has a negative influence by affecting the exit thickness. A formula for calculating the exit thickness after snake rolling is proposed and validated by data from the finite element models. Thus, snake rolling is suggested to be used in the downstream pass of hot rough rolling considering that the influence of thickness and the offset distance should be controlled in a reasonable range.

2018 ◽  
Vol 190 ◽  
pp. 11004
Author(s):  
Tao Zhang ◽  
Lei Li ◽  
Shihong Lu

Aluminium alloy thick plate is widely used in field of aerospace and automobile industry for its light weight, high strength, good corrosion resistance and formability. Hot rolling is the key process of preparation for thick plates, however, the conventional symmetrical rolling process causes large deformation on the surface and small deformation in the central portion of the thick plate, resulting in inhomogeneous deformation, microstructure and property distributions through the thickness direction of the plate. Asynchronous rolling is beneficial for deformation permeation into the central part of thick plate with introduction of strong shear strain due to velocity asymmetry of two work rolls. However, the plate will bend towards the slower roll due to deformation asymmetry at upper and lower surface of the plate and serious bending is bad for multi-pass rolling process. Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is adopted in this study. Compared to asynchronous rolling, there is a horizontal offset distance of upper roll in outlet direction. A moment will be applied to the plate in the opposite direction of bending towards the slower roll by an offset distance of the slower roll. The comparisons of distributions of equivalent strain, temperature, DRX fraction and average grain size between symmetrical rolling and asymmetrical shear rolling are studied. The effects of velocity asymmetry and offset distance on microstructure variation and microstructure distribution at different positions of the plate are studied. Due to larger velocity of lower work roll, larger equivalent strain and higher temperature appear at lower layer of the plate, which results in higher DRX fraction and finer grain size. The speed ratio contributes greatly to sufficient DRX process and finer grain size; while the ascending offset distance decreases the DRX fraction. Therefore, speed ratio plays significant role in deformation permeation and grain refinement in asymmetrical shear rolling and the offset distance is mainly used to decrease the bending behaviour of the plate. This study can provide guidance to thick plate preparation with good properties in asymmetrical rolling process.


2010 ◽  
Vol 97-101 ◽  
pp. 2955-2960
Author(s):  
Xiao Zhong Du ◽  
Quan Yang ◽  
Zheng Yi Jiang ◽  
Xiao Ping Zhang ◽  
Xiao Chen Wang

Asymmetrical rolling is usually used on some special rolling produce. It offers lower rolling pressure, more reduction and better crystallographic textures. In recent years asymmetrical rolling has become more important due to realization of improved properties of the strip. In this paper, a elasto-plastic finite element method code has been developed to simulate the asymmetrical rolling of strip, considering unequal roll radii, unequal speed ratio between the upper roll and lower roll, different exit thickness and different reduction. Meanwhile, The profile, crown and edge drop of strip, as well distribution of front tensile stress were discussed in different rolling process. It makes better preset values for the online control system and good results was obtained.


2014 ◽  
Vol 941-944 ◽  
pp. 1895-1900 ◽  
Author(s):  
Fa Shen ◽  
Wen Jing Yu ◽  
Wen Fei Peng ◽  
Xue Dao Shu ◽  
Chun Jie Yu

The spiral shaft parts have been widely applied in machinery and equipment manufacturing industry, the paper based on DEFORM-3D, the rigid-plastic finite element model of cross wedge rolled spiral shaft parts was established. The rolling process was simulated, the strain laws were analyzed, and the characteristics of metal flow were explored. From which we can find Plate cross wedge rolled spiral shaft parts is completely feasible. The results provide the theoretic basis for precision deformation of cross wedge rolled spiral shaft parts.


Author(s):  
Pujun Hao ◽  
Anrui He ◽  
Wenquan Sun

A finite element model (FEM) was developed to study the plane shape of an aluminum alloy thick plate after angular rolling. Results show that the plane shape is a parallelogram after the first pass of angular rolling. When the angular rolling process is completed after a second pass, the plane shape becomes symmetric about the center lines in both length and width directions. The width increases more at the edge that enters the deformation zone earlier. Next, a mathematical model to predict plane shape after angular rolling was proposed based on a sectional calculation method. By simulating the longitudinal rolling process, spreads from different plate widths were obtained and used in the mathematical model. By comparing these results with results from the FEM, the accuracy of the mathematical model was verified. Because of its short calculation time, the mathematical model can be used in practice during the production process.


2012 ◽  
Vol 184-185 ◽  
pp. 501-504
Author(s):  
Wen Fei Peng ◽  
Si Jia Jiao ◽  
Xue Dao Shu ◽  
Kang Sheng Zhang

Finite element model of Cross wedge rolling asymmetric shaft is established, contrasting with symmetrical rolling, the axial relative displacement of weak-side and strong-side’s metal in asymmetric cross wedge rolling is analyzed. The results show that: axial relative displacement asymmetrical rolling on the weak-side undergo the process of “increase-decrease-unchangeableness” and axial non-uniform deformation increases; axial relative displacements on the strong-side undergo the process of “decrease- unchangeableness” and axial non-uniform deformation decreases. The results provide a theoretical basis for the cross wedge rolling asymmetric shaft parts.


2010 ◽  
Vol 97-101 ◽  
pp. 2748-2751
Author(s):  
Xin Song ◽  
Jing Zhong Xiang ◽  
Jia Zhen Zhang

Fatigue crack propagation of aluminium alloy 7049-OA has been studied by non-linear finite element business-oriented software ABAQUS, and elastic-plastic finite element models of static fatigue crack and dynamic fatigue crack of center crack panel (CCP) specimens are also built. Based on the finite element computation results, the differences of stress and crack opening displacement around crack tip of static crack model have been compared with those of dynamic crack model. The compared results showed that the finite element computation results of dynamic crack model can be replaced by the results calculated by the static crack model. Fatigue crack tip parameters of aluminium alloy CCP specimens can be calculated by elastic-plastic finite element model of static crack. This is an effective method to cut down the computation expense and promote the computational efficiency.


2011 ◽  
Vol 103 ◽  
pp. 488-492
Author(s):  
Guang Bin Wang ◽  
Xian Qiong Zhao ◽  
Yi Lun Liu

In the rolling process, deviation is the phenomenon that the strap width direction's centerline deviates from rolling system setting centerline,serious deviation will cause product quality drop and rolling equipment fault. This paper has established the finite element model to the hot tandem rolling aluminum strap, analyzed the strap’s deviation rule under four kinds of incentives,obtained the neural network predictive model and the control policy of the tail deviation.The result to analyze a set of fact deviation data shows this method may control tail deviation in preconcerted permission range.


2012 ◽  
Vol 706-709 ◽  
pp. 1421-1426
Author(s):  
Zheng Yi Jiang ◽  
Xiao Wei Cheng ◽  
Xiao Zhong Du ◽  
Dong Bin Wei ◽  
Xiao Feng He

In this paper, finite element models of the strip shape during cold rolling of ultra thin strip in both symmetrical and asymmetrical rolling cases have been successfully developed, and the strip shape such as the thickness distribution along the strip width has been obtained. The strip shape and edge drop are discussed under both symmetrical and asymmetrical rolling conditions. Simulation results show that the asymmetrical rolling can reduce strip edge drop dramatically. The work roll edge curve also affects strip shape significantly. The developed finite element model has been verified with the experimental values.


2013 ◽  
Vol 535-536 ◽  
pp. 322-325 ◽  
Author(s):  
Yeong-Maw Hwang ◽  
Kai Neng Hwang ◽  
Chia Yu Chang

This study is to investigate the effects of the process parameters on the heading load and metal flow pattern during heading and thread-rolling processes of LZ91 magnesium alloy screws. A heading process composed of two stages is proposed. The material flow pattern of the billet inside the die is analyzed using the finite element analyses. The effects of the upper die velocity, temperatures and friction factors on the heading loads and product quality are discussed. On the other hand, in the thread-rolling process, the effects of the friction factor on the effective stress, effective strain, and tooth height are investigated. Finally, heading and thread-rolling experiments are conducted using a self-designed die set and a lubricant of MoS2. The experimental values are compared with the simulation results to verify the validity of the finite element models and the proposed heading procedures.


2010 ◽  
Vol 154-155 ◽  
pp. 1255-1261
Author(s):  
Hai Yan Li ◽  
Yi Du Zhang ◽  
Hong Wei Zhang

Based on “physical field coupling” finite element method, the generation of residual stress and interactive coupling effect were analyzed during the forming process of aluminum alloy thick-plate. Therefore, comprehensive residual stress generated from rolling, quenching and stretching was obtained. The finite element model was proved effective by comparing the results of simulation and experiment. Results show that percent reduction has significant influence to the distribution and magnitude of rolling stress; There is a coupling effect between rolling stress and quenching stress, which represents a basic state; Furthermore, after stretching the distribution of coupling stress remains, but the value reduces greatly; The residual stress has got the minimum, when stretching is near 3%.


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