环件宽径比对环件冷辗扩工艺的影响规律研究

基于Abaqus/Explicit提供的显式动力学有限元算法,对矩形截面环件冷辗扩进行了有限元数值模拟,揭示了环件宽径比对环件冷辗扩过程中环件端面质量、轴向宽展率、辗扩力、辗扩力矩以及金属流动特性的影响规律,并从金属塑性成形原理和塑性加工力学等角度对这些规律进行了合理的解释,从而获得了环件宽径比对冷辗扩成形的影响规律,为环件冷辗扩在实际应用中环件宽径比的选择提供了依据,对揭示冷辗扩成形机理也具有十分重要的意义.     

基于Abaqus的梯形环件冷辗扩的有限元模拟

冷辗扩又称环件轧制,是近年来在轴承套圈加工中逐步采用的新工艺,是机械精密轧制技术与精密塑性成形技术的集成创新,具有显著的节能,节材,降低生产成本和提高零件性能等突出优势,在机械、汽车、石油化工、航空航天和原子能等领域有着十分广阔的应用前景。目前冷辗扩技术大都应用在截面对称性很好的环件的辗扩成形中,形状复杂环件的辗扩成形在理论方面虽取得了一些成果,但是由于复杂环件冷辗扩成形的过程中影响因素很多,辗扩过程中的一些参数发生改变,使得环件形状不理想。     

环形零件辗扩成形工艺研究现状与发展趋势

环形零件的辗扩成形工艺是一种局部加载连续成形工艺,成形过程中变形区材料在高温和外载荷作用下经历了非稳态、非线性的塑性变形。为探讨辗扩工艺中金属塑性变形机理,促进该工艺的改进、完善和推广新应用,国内外学者利用理论分析、数值模拟和试验研究等方法,对辗扩成形工艺过程、工艺参数及其对材料组织、性能的影响规律进行系统深入的研究。综合论述这种先进成形工艺研究现状;分析辗扩成形工艺参数理论与试验研究、环件辗扩过程组织演变规律数值模拟、环件辗扩成形过程成形/成性一体化调控等方面的发展趋势;针对目前环件辗扩成形工艺存在的流程长、能耗大、浪费材料等问题,提出环件短流程铸辗复合成形新工艺,并探讨这种新的短流程工艺的重点研究内容和推广应用前景。     

混合硬化弹塑性本构关系及其在环件冷辗扩模拟中的应用

采用数值模拟方法和混合硬化弹塑性本构关系,提出了基于弹性张量的应力补偿更新算法,引入等向强化系数,给出了有限元计算步骤,基于ABAQUS/Explicit平台开发了子程序VUMAT,并在单个单元模型中验证了其可靠性。将其应用于环件冷辗扩过程模拟中,着重研究了等向强化系数对环件冷辗扩成形的影响规律。结果表明,随着等向强化系数的增大,辗扩力、辗扩力矩增大,鱼尾形状系数减小,环件外圈金属受各向异性硬化影响较大,进而从理论上进行了解释。研究结论指出该研究对环件冷辗扩成形工艺具有指导意义。     

沟球断面环件冷辗扩三维有限元模拟与工艺设计

沟球断面环件冷辗扩是滚珠轴承套圈制造新工艺。以有限元软件Abaqus为平台,根据冷辗环机实际工作条件,建立从矩形断面毛坯冷辗扩成形沟球断面环件的三维弹塑性动力显式有限元模型。通过动力显式有限元数值模拟,研究沟球断面环件冷辗扩变形过程,揭示出该环件冷辗扩中直径增长和圆度变化规律。基于数值模拟结果,优化设计矩形断面环件毛坯尺寸和冷辗扩工艺参数。在D56G90冷辗环机上进行沟球断面环件冷辗扩试验,验证了数值模拟结果,并采用矩形断面环件毛坯成功冷辗扩出了沟球断面轴承套圈。     

梯形轴承外圈冷辗扩的有限元模拟

基于阶梯形环件轧制理论,初步设计模具、毛坯和工艺参数,应用Abaqus软件建立轧制的三维模型,并利用Abaqus/Explicit显式算法对阶梯形环件轴承外圈的冷辗扩成形进行模拟分析,揭示出梯形环件轧制缺陷的成形机理和轧制过程中金属流动的特性.并在KKD160精密辗环机上进行轧制试验,验证了毛坯和模具的形状合理.     

42CrMo钢铸造环坯辗扩成形理论与工艺分析

与目前常用的环类零件生产工艺相比,基于环形铸坯的短流程铸辗复合成形新工艺具有节约材料和能源、缩短工艺流程等优点。以轴承环件常用的42CrMo钢为研究对象,探讨基于环形铸坯的轴承环件辗扩成形机理和工艺。借助于热力模拟试验和组织测试分析,揭示42CrMo钢在热变形条件下组织演变机理和规律;通过理论分析与数值模拟,研究铸坯环件辗扩成形过程中变形工艺参数及其对金属变形和组织演变规律的影响,实现环形零件铸辗复合成形/成性一体化调控;在洛阳LYC轴承股份有限公司,完成轴承套圈铸辗复合成形工业试验。试件的力学性能测试结果表明,这种短流程铸辗复合成形新工艺生产的环形零件具有良好的力学性能指标,可满足工业使用要求。     

外球面轴承外圈冷辗扩有限元分析

基于环件轧制理论,分析外球面轴承外圈的冷辗扩工艺,应用Abaqus软件建立轧制的三维模型,并利用 Abaqus/Explicit显式算法对外球面轴承外圈的冷辗扩成形进行模拟分析,研究了不同的模具结构、尺寸和进给规范对成形过程的影响,揭示了外球面轴承外圈冷辗扩成形的机理.     

环件冷辗扩芯辊进给速度规范设计

针对环件冷辗扩的特点，结合环件冷辗扩机的工作原理，提出了四种不同的芯辊进给速度设计规范。以矩形截面为分析对象，根据进给速度为常数、每转进给量为常数、环件外径增长速度为常数和随动导向辊圆心的旋转速度为常数这四种控制条件，提出了芯辊进给速度设计方法，推导出了直径的增长规律。根据试验数据，以Abaqus为平台，模拟了四种进给速度规范下的辗扩过程，分析了冷辗扩力和环件成形的圆度变化规律。总结了四种设计方案的优缺点，提出了在不同辗扩阶段采用不同的进给规范的设计思路，以期能为环件冷辗扩的工艺和控制设计提供新的理论依据。     

环件冷辗扩中单辊随动导向运动规律研究

根据立式单导向辊随动导向冷辗环机的实际工况，建立了矩形截面环件和深沟球截面环件冷辗扩的运动学模型，分析两种环件的直径变化规律，研究了一定辗扩工艺条件下导向辊的运动规律。建立根据冷辗扩工艺来确定导向辊运动的一整套设计方法，并用MATLAB编写求解程序以求解所有的设计参数。精确地控制导向辊的运动规律有利于提高环件冷辗扩的精度。研究结果为冷辗环机的设计制造提供了依据。     

Modeling and simulation of cold rolling process for double groove ball-section ring

Double groove ball-section ring (DGBR) is an important part of bearing rings. Cold DGBR rolling is an advanced continuous and local plastic forming technique by reducing cross section and increasing the diameter of ring blanks between rotating roll, and can directly obtain the DGBR with good mechanical properties. In this paper, the cold DGBR rolling processes from some initially rectangular blanks are investigated by using 3D-FE numerical simulation to reveal its deforming rules. Firstly, by analyzing the dimension relationship between rectangular blank and deformed ring, a new blank size design method is proposed based on rolling ratio and the volume conservation law, and thus a series of different original blanks can be precisely designed under different rolling ratios for a same final required DBGR. Secondly, under the ABAQUS/Explicit software environment, a reliable guide roll adaptive control-based 3D-FE model for cold DGBR rolling process is built via elastic–plastic dynamic explicit finite element method. Finally, several rectangular blanks are designed under different roll ratios and the deforming behaviors of cold DGBR rolling process are investigated with thorough numerical simulation. The results show that: (1) the maximum radial thickness of ring H reduces firstly slowly and then rapidly after the ball groove achieves its final shape; (2) the diameters of the ring expand gradually during the whole process and no sudden change occurs just when the final shape of the ball groove is completely formed; (3) the largest deformation occurs around the ball groove all the time under small rolling ratio; while under large rolling ratio, it occurs first around the ball groove and then gradually transfers to the ring outer surface; and (4) the inhomogeneous deformation degree increases with the progress of the process, and for final parts, it increases slowly first with the increasing of roll ratio and then fast when the roll ratio is greater than a certain value. These results will not only reveal the forming mechanisms of cold DGBR rolling process but also provide a basis to blank optimum design and process adaptive control of the relevant profiled ring rolling processes.     

宽带钢冷连轧机综合耦合模型的建立与分析

宽带钢冷连轧过程中,板形、板厚和张力控制之间存在着很强的耦合关系,相互影响对方的调节功效。为了进一步提高控制精度,进行解耦设计实现解耦控制是十分有效的手段,而其前提和基础就是冷连轧机综合耦合模型的建立和分析。首先,运用轧制理论对轧制过程中板形、板厚和张力控制的各种影响因素进行了系统的分析,然后考虑执行内环的动态特性建立冷连轧机综合耦合模型,以定量地描述轧制过程中辊缝、弯辊力、本架轧辊速度、前架轧辊速度和出口厚度、出口凸度、出入口张力之间的耦合影响关系。最后,基于Matlab/Simulink工具,采用此耦合模型对某冷连轧机末机架的耦合特性进行仿真分析,指出对其进行解耦控制的必要性。     

Research on interactive influences of parameters on T-shaped cold ring rolling by 3d-FE numerical simulation

Cold ring rolling is a much complex physical process with multi-factors. Two forming parameters, the feed rate of mandrel and the rotational speed of main roll, affect the quality of deformed ring significantly and the feed amount per revolution of ring in the form of their ratio. By their ratio, the interactive effects of the two forming parameters on the T-shaped cold ring rolling process are explored through 3D-FEM in Abaqus software. The results show: firstly the study objects (roll force, growth rate of diameter, degree of inhomogeneous deformation, filling capability of groove, average side spread and fishtail coefficient) are almost invariable if the two parameters are increased (or decreased) proportionally; secondly whether the ratio is changed by the feed rate of mandrel or by the rotational speed of main roll, the variation of each study object with the ratio is approximately the same; thirdly the increase of the ratio is beneficial to the growth of diameter and the restrictions of inhomogeneous deformation, average side spread and fishtail coefficient, but it causes the roll force to increase and the filling capability of groove to decrease.     

立式轧环机轧制中环件运动学规律

提出在轧制过程中环件中心不在芯辊和驱动辊中心连线上的轧制几何模型，并基于此模型导出环件中心位移、速度、加速度、环件转动惯量及转速和转动加速度的计算公式，建立了环件的运动学参数与环件壁厚和轧制进给量之间的关系，为环件轧制过程的在线测量和控制提供理论依据。     

基于CFD方法的冷轧过程乳化液特性研究

应用CFD工具FLUENT建立冷轧过程乳化液内部压强及轧板所受压力求解分析模型,计算分析冷轧过程乳化液进口速度对乳化液内部压强及轧板所受压力的影响。模拟结果表明,乳化液内部压强随着乳化液进口速度的加大而增加,轧板所受压力也随之增加。通过对比生产现场的轧制力数据,得到乳化液的最优进口速度。通过分析不同油水混合比例乳化液的离水展着性,得到最优的油水混合比例,使得冷轧润滑效果最好,进而实现最优的板面质量。     

Numerical simulation and experimental study on geometry variations and process control method of vertical hot ring rolling

The accurate geometry and effective control during the ring rolling process are the prerequisites for the ring products’ precise forming. In this paper, the interaction modes and rules between ring and rolls in vertical hot ring rolling (VHRR) process are analyzed, and the change laws of the ring’s geometry are studied. Based on the ABAQUS/Explicit software and its subroutine VUAMP, the finite element (FE) model of the VHRR process with measurement and control is established. Then, the ring rolling process of a groove-section profile ring is simulated. During the simulation, the ring’s outer diameter, roundness error, and the stability of the rolling process are detected in time, and the close-loop control of feed plan of the drive roll and measuring roll are also employed. The results obtained show the following: (1) Four feed stages are divided by means of a step-down feed movement, that is, bite stage, main rolling stage, precise forming stage, and sizing stage. (2) At bite and main rolling stages of the VHRR process, the ring’s center swings in a spiral line, and the rolling process is unstable, the ring’s roundness becomes worse, while the process is entering the precise forming stage, by means of the guide roll, the rolling process becomes steady and the ring’s roundness tends to be better. (3) The measuring roll contacts with the ring at the main rolling stage, afterwards, it is pushed back at the precise forming stage by ring’s growth. When the measuring roll meets the desired displacement value, a stop feeding command will be fed back, and the ring rolling process enters the sizing stage. At the sizing stage, the ring’s outer diameter still increases a little. (4) A series of VHRR experiments are conducted, and FE results are in good agreement with experimental results. The absolute errors of the ring’s outer diameter and the roundness are within 1 mm. The research results of this paper have practical significance to guide the VHRR production.     

Mathematical model for cold rolling and temper rolling process of thin steel strip

A mathematical model for cold rolling and temper rolling process of thin steel strip has been developed using the influence function method. By solving the equations describing roll gap phenomena in a unique procedure and considering more influence factors, the model offers significant improvements in accuracy, robustness and generality of the solution for the thin strip cold and temper rolling conditions. The relationship between the shape of the roll profile and the roll force is also discussed. Calculation results show that any change increasing the roll force may result in or enlarge the central flat region in the deformation zone. Applied to the temper rolling process, the model can well predict not only the rolling load but also the large forward slip. Therefore, the measured forward slip, together with the measured roll force, was used to calibrate the model. The model was installed in the setup computer of a temper rolling mill to make parallel setup calculations. The calculation results show good agreement with the measured data and the validity and precision of the model are proven.     

20辊轧机轧件截面形状与边部减薄预报软件开发

利用接触元双坐标法（CEM）建立了双AS—U—Roll系统森吉米尔轧机轧制过程中轧件及辊系变形行为的CEM函数矩阵,并开发了SM4SM软件。该软件能够很好地预报各种轧制条件下轧件截面形状、轧件边部减薄、轧制力、轧辊挠曲等功能。文中应用SM4SM,分析了第一中间辊锥角、锥度长度和窜辊长度对轧件截面形状和轧件边部减薄控制的影响。研究结果对冷轧过程控制轧件板形和边部减薄具有重要的参考价值。     

SENSITIVITY ANALYSIS FOR ROLLING PROCESS BASED ON SUPPORT VECTOR MACHINE

A method for the calculation of the sensitivity factors of the rolling process has been obtained by differentiating the roll force model based on support vector machine. It can eliminate the algebraic loop of the analytical model of the rolling process. The simulations in the first stand of five stand cold tandem rolling mill indicate that the calculation for sensitivities by this proposed method can obtain a good accuracy, and an appropriate adjustment on the control variables determined directly by the sensitivity has an excellent compensation accuracy. Moreover, the roll gap has larger effect on the exit thickness than both front tension and back tension, and it is more efficient to select the roll gap as the control variable of the thickness control system in the first stand.