HDSA车轮立式轧制变形分析

掌握车轮轧制过程的金属变形规律是制定和优化车轮轧制工艺的重要依据。以HDSA车轮为研究对象,采用有限元法对其立式轧制过程进行模拟,分析车轮轧制过程中轮辋扩径、宽度变化、变形深透性、应力分布及辐板拉薄等现象和规律。结果表明:轧制13圈时轮辋扩径速度最大,5.1 mm/圈;轮辋宽展量在14～18圈达到峰值,最大道次宽展量达5.5 mm;终轧时,初始踏面下25 mm范围内,随着深度的增加,等效应变呈线性降低,31 mm深度处的金属有最小应变0.23;车轮轧制时辐板主要承受周向和径向拉应力,并导致辐板被拉薄,终轧后辐板最大拉薄量达到3.3 mm。     

异型丝辊拔过程中宽展的研究

研究压下率、辊拔道次、摩擦系数、后张率对异形丝辊拔过程中宽展的影响。     

关于轧机平面图/宽度设定模型(PVM)的研究

论文主要从自然宽展、狗骨形状、狗骨展平造成的宽展以及宽度压下量的分配等方面入手,对轧机平面图/宽度设定模型进行了探讨和研究,该模型轧制灵活,能实现高精度轧制,对我国轧机实现全面自动化控制具有重要的现实意义。     

平辊轧制棒材的探讨

平辊轧制棒材是一项以无孔槽轧辊生产棒材产品的新技术。它适用于生产棒材的粗轧和中轧机组。运用平辊轧制工艺时,必须分析金属流动,预测凸度值、宽展值,控制脱矩现象。     

弯辊和串辊对带钢板形影响

基于有限元软件ANSYS建立了冷轧六辊轧机的三维弹塑性有限元参数化模型。将轧机实体模型转换成有限元模型,根据轧机的工作方式提炼出边界条件和载荷条件,施加在有限元模型上。参数化模型采用ANSYS参数化设计语言APDL编写。通过修改程序中的参数,计算分析了弯辊力、中间辊的串辊量以及带钢宽度等参数对带钢形状和辊缝的影响。计算结果表明:当带钢宽度小于1 300 mm时,调整弯辊力对带钢板形的改变较为明显;当带钢宽度大于1 700 mm时,调整弯辊力对改变带钢板形的作用变得非常小,此时通过连续可变凸度轧辊（CVC）的串辊来调节板形更有效。该结论与冷轧厂实践结论一致。     

环件冷辗扩中宽展的实验研究

根据D56G90型环件冷辗扩机的工作原理和实际工作情况，选取了影响矩形截面环件冷辗扩宽展的2种主要因素：进给速度和宽径比来设计研究宽展变化的实验方案。通过对实验结果的分析表明：进给速度和宽径比的增加都可以在一定程度上减小环件的宽展，使环件端面平整。同时，也发现了环件内外侧的宽展率不相同。这些现象的本质是环件冷辗扩过程中的径向和轴向塑性区的分布不同。使用MATLAB编写了数值计算程序，采用二项式拟合的数值方法，总结归纳出了进给速度和宽径比与宽展率之间的解析公式。     

系列货叉成形辊锻新工艺的研究

本文对长轴类延伸型系列货叉锻件经过试验研究,制定了成形辊锻新工艺;提出新的模具设计方法;解决了小压下大宽展问题;避免了货叉弯曲过程中的拉缩现象。     

热连轧精轧宽度控制技术的研究及应用

在热轧带钢其他尺寸精度普遍较高的情况下,宽度控制精度的提升变得越来越重要。提出了一种新的精轧带钢宽度控制综合解决方案：针对带钢头部宽度控制,开发精轧机架冲击速降自学习模型,以减少带钢头部拉窄现象;通过合理配置精轧活套张力稳定因子,减少带钢中部宽度波动现象;通过精轧宽度反馈控制和宽展预测模型修正功能,提高带钢全长宽度精度。相关研究成果已成功应用于宝钢集团某热轧产线三电自主集成改造项目中,改造后带钢宽度控制精度得到显著提高。     

微细铝丝辊式连续矫直工艺参数的优化

为了降低矫直机在连续矫直时对微细铝丝材料的损害.文中根据矫直原理,通过分析原始曲率、反弯曲率及残留曲率对铝丝矫直的影响,利用辊式矫直的工艺参数设计了微细铝丝矫直机构.实验结果表明:在辊式矫直中采取辊数为9,辊径为15mm,辊距为17mm时,微细铝丝的矫直截面直径为0.35mm的精度可以满足≤5mm/20cm.     

14辊轧机辊系变形的有限元分析

针对现场应用的14辊轧机,利用三维有限元软件MSC.MARC建立三维辊系弹性变形有限元模型,求解三维辊系复杂变形,分析第一中间辊抽动和中间辊凸度对承载辊缝的影响。研究得出第一中间辊抽动量在0-50mm时,带材边部厚度的调节范围;中间辊凸度与轧后板凸度呈线性关系,即中间辊凸度越大,辊系的横向刚度也越大。     

Preset model of bending force for 6-high reversing cold rolling mill based on genetic algorithm

The hydraulic roll-bending device was studied, which was widely used in modern cold rolling mills to regulate the strip flatness. The loaded roll gap crown mathematic model and the strip crown mathematic model of the reversing cold rolling process were established, and the deformation model of roll stack system of the 6-high 1 250 mm high crown (HC) reversing cold rolling mill was built by slit beam method. The simulation results show that, the quadratic component of strip crown decreases nearly linearly with the increase of the work roll bending force, when the shifting value of intermediate roll is determined by the rolling process. From the first pass to the fifth pass of reversing rolling process, the crown controllability of bending force is gradually weakened. Base on analyzing the relationship among the main factors associated with roll-bending force in reversing multi-pass rolling, such as strip width and rolling force, a preset mathematic model of bending force is developed by genetic algorithm. The simulation data demonstrate that the relative deviation of flatness criterions in each rolling pass is improved significantly and the mean relative deviation of all five passes is decreased from 25.1% to 1.7%. The model can keep good shape in multi-pass reversing cold rolling process with the high prediction accuracy and can be used to guide the production process.     

Analysis of the thermal profile of work rolls in the hot strip rolling process

A 2-dimension axisymmetric model was developed by the finite-difference method, which can be used to predict the transient temperature field and thermal profile of work rolls in the hot strip rolling process. To demonstrate the accuracy and reliability of the solution developed, the calculation results were compared with the production data of a 1700 mm hot strip rolling mill and good agreement was found between them. The effect of strip width and roll shifting on the thermal expansion of the work rolls was studied.It is found that the strip width has marked effect on the efficient thermal crown. Initially, when the rolling strip changes from narrow to wide, a bigger efficient thermal crown can be quickly achieved; afterwards, when the rolling strip changes from wide to narrow,not only the influence of uneven wear can be reduced but also the excessive efficient thermal crown can be avoided. It is also found that the work roll shifting has a determinate but not obvious effect on the reduction of the efficient thermal crown, and will make the strip shape unstable without being used properly.     

Research on relationship between geometrical dimensions and elongation of Polycarbonate tensile specimen

To provide convenience for the translation among specimens,orthogonal experimental method was used to research the relationship between geometrical dimensions(length,width and thickness) and total elongation of polycarbonate sheet,and simulations of tensile specimens with different geometrical dimensions had been conducted by the finite element method,then regression analysis method was used to create the relationship formula between geometrical dimensions and total elongation.It was found that:the shorter the length of specimen is,the better the plasticity is,and they had the power exponent relationship;the larger the width and thickness are,the better the plasticity is,and they had the direct proportion relationship with the total elongation.     

平整延伸率对Ti-IF冷轧带钢力学性能的影响

冷轧带钢的力学性能与退火后的平整工艺有关。通过对Ti-IF带钢不同延伸率的试验研究,找出平整延伸率对力学性能影响关系,有利于指导生产和产品性能的稳定控制。     

冷轧TRB薄板的连续退火工艺试验研究

为了探索连续退火工艺对TRB板组织与性能的影响,在实验室采用四辊可逆式冷轧机进行单厚度过渡区TRB板轧制,对轧制的DP590双相钢和22Mn B5热成形钢TRB薄板进行模拟连续退火试验,利用光学显微镜和扫描电镜,以及拉伸和硬度试验方法研究钢板退火后各厚度区的组织与力学性能差别.研究表明:TRB板变厚度区的最大厚度偏差为0.03 mm,长度误差1.0 mm.TRB板在连续退火的冷却段和过时效段,其薄区温度较过渡区和厚区的温度偏低57~20℃,导致DP590钢板薄区的抗拉强度和伸长率较高,屈服强度与厚区的相当,而22Mn B5钢TRB板的屈服与抗拉强度偏高.在TRB板的变厚度区内维氏硬度波动较小.根据厚区的厚度来制定冷轧DP590双相钢TRB薄板的连续退火工艺,将更有利于保证钢板的组织与力学性能,对22Mn B5热成形钢TRB薄板建议采用罩式退火.     

影响板带材轧制头部翘曲因素的正交实验研究

用正交实验方法,对影响板带材轧制头部翘曲的因素进行了研究.因素有上下轧辊直径比、压下率、导入角和轧辊转速.正交实验是L25(45),研究表明:辊径比对头部翘曲影响最大,且影响趋势变化复杂;当板较厚时,辊转速的影响也较大,导入角的影响最小;当板较薄时,导入角的影响较显著,辊转速的影响最小;来料板厚不同,各种因素的影响趋势变化呈现了不同的规律,来料板厚也是影响头部翘曲的一个主要因素.优化了实验轧机控制头部翘曲的工艺参数.     

Backup roll contour of a SmartCrown tandem cold rolling mill

SmartCrown was a new system developed by VAI for improving the strip profile and flatness control first applied in 1700mm tandem cold rolling mills at Wuhan Iron & Steel (Group) Corporation (WISCO). After tracing and testing, the application of the conventional crown backup roll matching the SmartCrown work roll of the production mill led to heavy and nonuniform wear, and the edge spalling of the backup roll often occurred. A 3-dimension finite element model of roll stacks was established, which was used to analyze the above-mentioned problems, and it was found that the main reason was the highly nonuniform contact pressure distribution between the work roll and the backup roll. A new FSR (flexible shape backup roll) was developed and applied in 1700mm tandem cold rolling mills. A lot of good actual effects of FSR, such as evident improvement in profile and flatness of strips,non-occurring edge spalling, wear uniform, and remarkable decrease in roll consumption were validated by long-term industrial applications.     

Improvement on strip flatness of cold temper mills by modifying roll contour shape

A study on roll gap profile (strip profile) control was accomplished in a 1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contour caused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finite element model, the effects of roll contours (ground and wear) on strip profile were investigated. The roll bending effect on strip thickness was also analyzed. It is pointed out that there are some special features of flatness control in the temper mill: during temper rolling, roll deformation is slight due to small rolling load, and the loaded roll gap profile mainly depends on work roll contour, while the backup roll has a little effect on gap crown; the effect of bending force on gauge can not be ignored due to the coupling between flatness control and gauge control. A new roll contour arrangement adaptable to the mill was presented and has been put into practical production. The application of the new set of rolls showed some good results: larger crown control range of work roll bender, higher rolling stability, better strip profile and flatness quality.     

Gauge-meter model building based on the effect of elastic deformation of rolls in a plate mill

The calculation error of the gauge-meter model will affect the gap setting precision and the self-learn precision of rolling force. The precision of the gauge-meter model is strongly influenced by plate width, working roll radius, backup roll radius, working roll crown, backup roll crown, and rolling force. The influence rules are hard to get by measuring. Taking a conventional 4-h plate mill as the research subject, these influences were transferred into the calculation of roll deflection and flattening deformation. To calculate these deformations, the theory of the influence function method was adopted. By modifying the traditional gauge-meter model, a novel model of the effect of roll elastic deformation on the gap setting was built by data fitting. By this model, it was convenient to analyze the variation caused by the rolling condition. Combining the elastic deformation model of rolls with the kiss-rolls method, a gauge-meter model was put forward for plate thickness prediction. The prediction precision of thickness was greatly improved by the new gauge-meter model.     

Forced transverse vibration of rolls for four-high rolling mill

In order to investigate the forced transverse vibration of rolls under distributed draught pressure and moment of bending roll force, the forced transverse vibration model of rolls for four-high rolling mill was established. The work roll and backup roll were considered as elastic continuous bodies that were joined by a Winkler elastic layer. According to Euler-Bernoulli beam theory, the forced transverse vibration of rolls was analyzed based on modal superposition method. The forced vibration equations were established when the draught pressure and moment of bending roll force were imposed on the rolls respectively. Numerical modeling was made on 2 030 mm cold tandem rolling mill of Baoshan Iron and Steel Company. Simulation results show that when the work roll is only subjected to different forms of draught pressures, the vibration curves of work roll and backup roll are quadratic curves with amplitudes of 0.3 mm and 45 μm, respectively. When only the moments of bending roll force are imposed on the work roll and backup roll, the vibration curves of work roll and backup roll are quadratic curves, and the amplitudes are 5.0 and 1.6 μm, respectively. The influence of moment of bending roll force on the vibration of work roll is related with the bending roll force.