考虑锥向金属流动的大型锥形筒节轧制力计算模型

由于大型锥形筒节存在锥度,考虑金属沿锥向的流动,首先采用微分分层计算法和切块法建立了大型锥形筒节轧制力力学模型;然后基于ABAQUS有限元软件,建立了大型锥形筒节轧制过程仿真模型。模型计算结果和有限元仿真结果表明：力学模型计算轧制力与有限元计算总轧制力的相对误差在20%以内。对比分析了力学模型和有限元模拟计算单位轧制力的分布。通过分析芯辊和外辊的转速比,得出了所建力学模型的稳定轧制的适用范围。     

新型压电无阀微泵效率分析及试验研究

提出了一种用于无阀压电微泵的新型效率模型,根据传统扩张/收缩管型结构设计出侧面带有环形面积新型锯齿型带锥度和无锥度两种微流道.用CFD软件对传统扩张/收缩型微流道及新型锯齿型微流道进行了三维流动模拟,绘制出几种微流道特性曲线,并用新型效率模型计算了三种微流道在两种限制条件(最大流量零压力头和最大压力头零流量)下的稳态效率,并进行了分析比较,结果表明由于结构改变,锯齿型微流道最大流量和压力损失实现了预期的变化,并且带锥度锯齿型微流道微泵稳态效率均大于标准扩张/收缩型微流道及无锥度锯齿型微流道微泵.最后制作出含有标准扩张/收缩及带锥度锯齿型微流道结构微泵,并对其进行试验,结果证明由于环形面积和锥度存在,带锥度锯齿形微流道微泵性能明显优于传统扩张/收缩型微泵.     

双金属复合管固-液铸轧复合轧制力模型研究

以传统双辊铸轧技术为基础,提出一种双金属复合管固-液铸轧复合近终成形工艺,利用专门的环形布流器,将液态覆层组元金属均匀地注入铸轧辊圆孔型与芯管基材所构成的环形结晶器内,利用快速凝固与轧制复合技术,将覆层金属均匀包覆于芯管基材表面。为揭示铸轧区内铸轧辊-覆层金属-芯管基材间的相互作用力学行为,利用Fluent软件对环形结晶器内覆层金属凝固过程进行热-流耦合分析,确定固相轧制复合变形计算区域。假设芯管基材为刚性体,可将固相轧制复合变形阶段视为纯减壁的带芯棒轧管过程,并依此推导固-液铸轧复合过程的轧制力工程计算公式,给出各参数的取值方法。在实验室条件下成功制备了外径38 mm、基层与覆层厚度均为4 mm的不锈钢/铝复合管,轧制力实测值与模型计算结果基本吻合,验证了工程计算公式的可靠性。研究成果对复合管固-液铸轧复合装备及工艺设计提供了理论依据。     

基于有限元的三辊行星轧制力模拟

采用有限元技术对三辊行星轧制力进行了模拟计算,论述了TP2铜管坯三辊行星轧制过程有限元模拟的关键技术与实现方法,建立了有限元计算模型,获得了轧制力的变化规律.研究表明:三辊行星轧制过程中,轧制力在坯料的周向方向呈120°分布变化,在轧制过程中坯料的形状、坯料与轧辊的接触部位时刻发生变化,轧制力呈现波动现象.     

轴承套圈坯料螺旋孔型斜轧成形数值模拟及分析

针对传统解析计算和物理试验不能有效揭示轴承套圈坯料螺旋孔型斜轧工艺轧制变形机理的问题,基于Abaqus/CAE有限元分析软件建立轴承套圈坯料螺旋孔型斜轧成形三维有限元模型,其关键点为设置轧辊与轧件网格表面为面接触以及网格内部表面为自接触,采用高温单向拉伸试验确定韧性断裂模型中坯料的损伤参数,添加STATUS变量输出控制网格畸变等,并分析了轧制过程中坯料的应变和应力以及轧辊的轧制力和力矩,结果表明坯料内部区域处于多向拉应力状态,易导致内部微缺陷的萌生和扩展。     

滚圆装置

图1a所示的锥度套有锥度大,小端直径小的特点。为了使坯料一次卷成形,我们自制了两轴滚压的压边式短锥管滚圆装置。其结构(图2)分下列几部分。     

铝合金薄壁异形截面辗扩成形宏微观模拟

环件轧制作为一种无缝环筒类构件先进塑性成形技术,目前还难以实现铝合金薄壁带筋锥筒构件的近净成形制造.针对2A14铝合金薄壁异形截面环件,建立其辗扩成形宏微观耦合分析有限元模型,选用矩形截面环件作为坯料,基于有限元模拟获得了优化后的轧制孔型,并探究坯料初始温度及芯辊进给速度对材料成形性和微观组织演变的影响规律,得到微观组织均匀且孔型填充性良好的辗环工艺参数.环坯温度为470℃,芯辊进给速度为1.2mm/s,主辊旋转转速为30 r/min,上锥辊的压下速度为0.6 mm/s为最优工艺参数,能够满足2A14铝合金异形截面辗扩形/性控制要求,可为实际生产提供理论指导.     

微米级钽箔材轧制工艺优化

本文主要介绍了以厚度0.2mm钽带为坯料,采用六辊冷轧机开坯+二十辊轧机冷轧和二十辊轧机直接开坯两种加工工艺方式,并试验选取合适的中间热处理制度,生产出0.008mm微米级钽箔材。通过两种加工工艺对比,得出采用六辊冷轧机开坯+二十辊轧机冷轧轧制方法,坯料的板型、表面质量及横向厚差得到优化,因此可以提高坯料及后续的微米级钽箔材轧制效率,提高成品率。     

轴承套圈坯料螺旋轧制工艺分析

在分析现行轴承套圈坯料锻造、无缝钢管生产和少或无切削生产工艺方法及特点的基础上,重点介绍了采用螺旋轧制方法生产套圈坯料的工艺方法、工作原理和可行性试验分析,对比几种工艺方法后得出了螺旋轧制生产工艺在节材、节能、环保等方面的优势。     

20CrMn钢双辊薄带振动铸轧细晶机理试验

为了改善传统双辊薄带铸轧板坯中存在的缩孔、裂纹、组织不均以及晶粒粗大等缺陷,提升双辊薄带铸轧产品带坯的力学性能,提出振动铸轧新技术,以细化铸轧带坯组织晶粒度,提高其力学性能。为了确定振动铸轧过程的细晶机理,分别在1 570℃和1 530℃两种开浇温度下进行20CrMn钢双辊薄带铸轧振动与非振动工况的对比试验,并对所得带坯微观组织及力学性能进行检测和分析。微观组织观察结果表明,在铸轧过程中振动可以有效细化产品带坯晶粒,其细晶机理为在凝固阶段振动可以提升熔池区形核率并促使振动侧枝晶尖端熔断,而在轧制阶段振动可以强化塑性变形区的动态再结晶;拉伸试验结果表明振动有效地改善了铸轧板坯的力学性能,开浇温度1 570℃时,沿轧制方向振动铸轧板坯较传统铸轧板坯屈服强度、抗拉强度和伸长率分别提高了12.11%、14.57%和38.9%,垂直轧制方向分别提高了7.72%、13.23%和34.8%;开浇温度1530℃时,沿轧制方向分别提高了9.22%、14.95%和31.25%,垂直轧制方向分别提高了21.36%、27.35%和42.86%。试验表明振动铸轧较传统铸轧不仅能在凝固阶段通过振动提高形核率,细化晶粒,还能在轧制段通过振动增强动态再结晶效果,改善材料微观组织结构,从而提升其力学性能。     

内台阶锥形环件轧制三维有限元模拟和工艺优化设计

以Abaqus三维有限元模拟软件为平台，对内台阶锥形环件的轧制过程进行了数值模拟，通过模拟计算揭示了内台阶锥形环件轧制缺陷的形成机理。根据轧制难度分析和有限元模拟结果，对轧制毛坯尺寸和轧制孔型进行了优化。采用铅环件试样在D51—160轧环机上进行了内台阶锥形环件的轧制试验，轧制了合格的内台阶锥形环件。模拟和试验结果表明，轧制毛坯尺寸和轧制孔型优化方案是合理的，基于变形模拟的轧环工艺优化方法是有效的。     

Effect of rolling ratio on groove-section profile ring rolling

Ring rolling is an advanced plastic forming technique which is used to manufacture precise seamless rings. Rolling ratio is regarded as a decisive parameter for the ring rolling process because it decides the blank dimension, reflects the ring deformation degree and influences the forming results. However, its importance for the ring rolling process is always neglected. In this paper, the effect of rolling ratio on the groove-section profile ring rolling is firstly investigated. The relationships between rolling ratio and blank dimension, rolling ratio and ring deformation degree are theoretically studied and a theoretical value range of rolling ratio is proposed. Then, with FE simulation, the influences of rolling ratio on the forming results are revealed. Based on comparison and experimental verification, a reasonable value range of rolling ratio is determined.     

Multi-field coupling finite element analysis for determining the influence of temperature field on die service life during precision-forming process of steel synchronizer ring

Failure analysis shows that increased die temperature caused by severe plastic deformation of material and heat conduction between hot billet and cavity significantly affects the distortion of gear cavity in steel synchronizer ring forging process. The forging process of steel synchronizer ring and die temperature distribution under different forging conditions are analyzed through finite element method. Simulation results show that severe plastic deformation occurs in the gear cavity. The improvement of lubrication condition results in decreased die temperature. When the initial billet temperature is high, the die temperature is also high. Increasing forging speed in a certain range facilitates the die temperature decrease. The distribution of die temperature in synthetic forming technology is more reasonable than that of one step forging. The synthetic forming technology is adopted in production to reduce the effects of severe plastic deformation caused by die temperature. The ejection mechanism and control system of the double disc friction press are improved to reduce the contact time between the hot billet and cavity. Experimental results show that synthetic forming technology is reasonable, and that the die service life is prolonged.     

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.     

基于Deform的刮板锻造工艺及模具设计研究

刮板由于其较复杂的结构,在模锻过程中常存在折叠、局部填充不足、欠压及裂纹等缺陷.实践表明,锻造过程中坯料与模具温度的控制不当、坯料与毛边槽设计不够不合理,导致金属流动困难是造成缺陷的主要原因.借助有限元仿真软件Deform,通过对刮板模锻成型的模拟分析,可以提供金属材料流动、模具填充、毛坯与模具温度变换等工艺分析数据.研究表明,Deform软件的应用,可有效地避免锻造缺陷的发生、提高材料利用率、减少试锻次数,对此类锻件的生产有很强的参考价值.     

A study on precision forging of spur gear forms and spline by the upper bound method

Precision forging is an important manufacturing procedure of spline and spur gear forms. It has advantages of improved strength, good tolerance, saving billet material, dispensing with the cutting, etc. In this paper, a mathematical model using an upper bound method is proposed for forging of spur gear forms and spline to investigate the plastic deformation behavior of billet within the die cavity. The material of solid billet was assumed as rigid–plastic and the shape of the tooth profile was accounted for the mathematical modeling of the kinematically admissible velocity field assumed for the plastic zone. The non-uniform velocity was employed for simulating the inhomogeneous deformation and the effect of barreling during the forging. Using the present model, various effects of forming parameter such as the friction factor, reduction, number of teeth, etc. upon the non-dimensional forging pressure, forging force and barreling of the spur gear forms and spline were analyzed systematically and the results compared with those of other researcher's analytical and experimental work. It is shown that the present modeling of the process improves knowledge of the process design performance for the precision forging of spur gear form and spline.     

钢坯无头轧制设备与关键技术分析

总结了无头轧制技术的发展情况与技术特点,介绍了无头轧制设备的主要组成部分,详细阐述了各部分的功能与特点,同时分析了闪光焊接的工艺过程,并着重分析了无头轧制关键技术,并对无头轧制技术的优越性与应用前景作了简要分析.     

内外局部约束下内齿圈滚轧成形

提出一种内外局部约束高效滚轧成形内齿圈新工艺,完成相关工艺构架并分析了其成形过程内外滚轧模具及工件的运动特征。搭建了采用2对滚轧模具的内齿圈滚轧试验平台,实现了内齿圈滚轧;建立多对滚轧模具内外局部约束下内齿圈滚轧过程有限元模型,完成了采用2对滚轧模具和3对滚轧模具的内齿圈滚轧过程有限元分析。试验与有限元结果表明,齿形形状完整、轮廓清晰,达到了设计齿高要求,内齿圈滚轧成形工艺可行;和试验获得齿高相比,有限元模型对齿形预测误差小于5%;通过适当的模具和坯料几何参数调整,可控制成形齿高、改善端面成形质量。研究结果对内复杂型面零件的高效省力成形工艺具有理论意义和参考价值。     

卷绕成形加工专用机床的设计

卷绕成形加工是指通过一根或数根具有一定廓形的带材卷绕形成零件主体部分的加工方法，该带材称为芯带。实现卷绕成形加工的关键在于芯带的成形和卷绕。文章讨论了芯带成形，卷绕设备，一体化机床及其控制系统的设计，并给出了应用例。     

Experiments study on the rolling process for heavy disk

Roll forming is a flexible and low-cost technique for manufacturing axisymmetric parts. The disk-rolling process using the revamped radial–axial ring rolling mill has been developed from the radial–axial ring rolling process. This paper introduces the disk-rolling process in detail. Experiments of rolling process for heavy hollow disks were carried out on the revamped Wagner RAW500/400 ring rolling mill. Qualified heavy disks of Q235 steel and 0Cr11Ni2MoVNb steel were successful rolled. The interrelations of billets and disks dimensions were researched on these experiments. It was found that all the qualified disks have a big section spread. Furthermore, the expansion of the inner hole diameter and the outer diameter of the disk during the rolling process were studied. The result indicates that, in order to roll a qualified disk, there must be enough section spread deformation for the billet.