基于粒子群算法的齿环精锻成形工艺参数优化

为提高同步器齿环热精锻成形的材料利用率,以初始温度、压制速度、摩擦系数、坯料内径和坯料高度作为设计变量,以充填性、成形缺陷和材料利用率3个指标的综合加权评分值作为优化目标,建立工艺参数与综合加权评分值的Kriging模型。应用Kriging模型结合粒子群算法,在可行变量空间内寻优,得到最优工艺参数组合为:T=697.5℃,v=190 mm·s-1,m=0.43,d=62.75 mm,h=12.5 mm。采用最优工艺参数组合进行工艺实验,锻件充填饱满,未见折叠缺陷,材料利用率提高至60.52%,为同类型的薄壁环型类锻件工艺参数设计及优化提供了定量的确定方法和依据。     

基于灰色系统理论的同步器齿环的成形工艺研究

针对铜质同步器齿环热精锻成形的材料利用率低、成形载荷大的问题,基于FORGE软件对齿环热精锻成形工艺进行研究。基于金属塑性成形理论,分析齿环成形过程中金属的流动规律。以坯料始锻温度、摩擦因数、坯料内径和坯料高度为变量,设计了4因素4水平正交试验,获得最大成形载荷、内外飞边径向尺寸数据。结合灰色系统理论对齿环热精锻成形工艺参数进行优化,获得最优工艺参数组合并进行工艺试验。试生产结果表明,齿环充填饱满、无折叠和开裂缺陷,材料利用率提高至63.73%,验证了优化工艺参数组合和灰色系统理论优化方法的可行性。     

基于响应面汽车变速器螺旋伞齿轮精锻成形工艺优化

针对螺旋伞齿在精锻时齿形成形质量差、成形载荷过大等缺陷,以某汽车变速器螺旋伞齿轮为研究对象,建立了以坯料始锻温度、摩擦系数以及压力机速度为设计变量,以最大成形载荷和终锻填充率为目标函数的二次多项式响应面模型,结合数值模拟方法以及Matlab优化工具箱,得到了优化的成形工艺参数为:坯料初始温度1000℃、摩擦系数0.3和摩擦压力机的成形速度200 mm·s-1.最后基于优化后的工艺参数,通过工艺试验验证了该模型的有效性,试验获得的螺旋伞齿齿形饱满,设备成形载荷满足要求.     

齿环精锻成形工艺参数的多目标优化设计

汽车同步器齿环在精密成形过程中局部容易出现应力集中和严重的材料损伤等缺陷。基于田口理论建立了材料损伤、最大等效应力分布和成形载荷的多目标优化模型。通过有限元模拟获得了同步器齿环精锻成形时的最优成形工艺参数组合:坯料初始温度650℃,凸模下压速率200 mm/s,摩擦因子0.45。经过生产试制获得了良好成形性能的同步器齿环。     

盘形滚刀刀圈锻造金属流线数值模拟研究

为了研究盘形滚刀刀圈锻造过程对金属流线的影响,基于塑形成形软件,建立了盘形滚刀刀圈锻造过程模型,通过改变始锻温度、锻造速度和其他主要参数,得到各参数对刀圈金属流线的影响,研究结果表明:锻造速度和始锻温度对金属流线的影响不大,在制坯过程中,摩擦因子、变形程度以及始锻高度对金属流线影响较大,增大摩擦因子、增大变形程度以及降低始锻高度对金属流线有优化作用,其中当始锻温度1 150℃,锻造速度15 mm/s,摩擦因子取0.5,变形程度80%,始锻高度不低于80 mm时能得到最佳成形效果。     

基于响应面法的机动车尾气后处理系统铝泵体的精锻工艺优化

针对机动车尾气后处理系统铝泵体精锻过程中出现的锻件凸台充填不完整、模具易开裂和飞边废料多等问题,建立了以锻件凸台端面充填率、终锻力比率和材料利用率为优化目标,以模具预热温度、坯料长度、坯料加热温度和飞边桥部高度为设计变量的二次多项式响应面模型。然后结合响应面法与差分进化算法对锻造参数进行优化,得到的最优锻造参数为:模具预热温度为350℃,坯料长度为83. 27 mm,坯料加热温度为490℃和飞边桥部高度为1. 15 mm。最后,采用最优锻造参数进行实际生产,生产出的锻件充填完整,提高了模具寿命和材料利用率。     

基于响应面法的喷射成形7055铝合金飞机轮毂锻造工艺优化北大核心CSCD

针对由于飞机轮毂形状复杂而导致的轮毂锻件充填不完整和模具磨损等问题,在某型号飞机起落系统的轮毂锻造中,采用喷射成形7055铝合金挤压棒,并采用热模锻方式和增加锻件预成形设计,建立以锻件的终锻充填率和终锻力为优化目标、以坯料预锻压下量、坯料加热温度、模具预热温度和模具下压速度为设计变量的响应面模型。利用二阶响应面法与Design Expert软件相结合,对轮毂锻件的工艺参数进行优化,确定最佳参数为:坯料预锻压下量为45.30 mm、坯料预热温度为430℃、模具预热温度为447℃、模具下压速度为5.00 mm·s。生产验证表明,改进后的预成形方案与工艺参数可以在较低的终锻力下,解决充填不完整的问题,生产出合格的产品。     

档位齿轮坯精锻成形工艺的数值模拟和试验研究

针对目前开式锻造档位齿轮坯工艺中耗能大,材料利用率低的问题,提出了一套新的闭式精锻成形工艺方案.利用有限元数值模拟软件DEFORM-3D分析了始锻温度、摩擦因子、压机速度对最大的成形载荷及成形质量的影响.并用优化的工艺参数进行生产试制,其结果与数值模拟吻合较好.     

轴盘类锻件的差温无模锻造有限元模拟分析

介绍了差温无模锻造技术在成形轴盘类锻件中的应用,分析了始锻温度、摩擦因数、加热区高度、热应变4个不同参数对坯料最终变形结果的影响。分析结果表明,提高始锻温度和摩擦因数有利于使坯料获得局部较大变形,而加热区高度和热应变对坯料最终变形结果无明显影响。     

锻坯/模具界面摩擦对汽轮机叶片模锻成形的影响

汽轮机叶片是将蒸汽能转换成机械功的关键部件,叶片精锻是叶片锻造的发展趋势.本文利用数值模拟方法,仿真了叶片金属在锻模型腔内的流动和成形过程,论述了摩擦条件对叶片精锻成形规律的影响.在锻坯金属变形充模的3个阶段,分析并讨论了不同的界面摩擦因子m对叶片模锻成形规律和模具失效的影响.数值实验结果表明:随着界面摩擦因子的增加,克服坯料金属界面流动阻力所需的附加模锻载荷增加,叶片锻件不同区域内的最大最小温度差、最大最小等效应变差,以及最大最小等效应力差增加;与此同时,锻模型腔局部最大等效应力和最大温度也增加.     

Controlling Flow Instability in Straight Spur Gear Forging Using Numerical Simulation and Response Surface Method

Workability domain without the onset of flow instability was developed by numerical simulation and response surface method(RSM) for complex-shaped straight spur gear forging. The processing map of AZ31 B alloys was calculated from flow stress curves and then integrated with the finite element model to simulate the distribution of flow instability in the straight spur gear undergoing isothermal forging process. Occurrence of flow instability depends on forging temperature, punch velocity and billet reduction. Taking forging temperature and punch velocity as design variables, while billet reduction as response variable, RSM of workability domain was established. Analysis of variance indicates that forging temperature is the most significant factor determining the appearance of flow instability in the forged gear. Flow instability is easier to take place at lower temperatures of 250 and 300 °C in the early stage of forging but at higher temperatures of 350 and 400 °C in the later stage of forging, which is attributed to different deformation mechanisms and dynamic recrystallization behaviors at different temperatures or deformation levels. Meanwhile, increasing punch velocity further reduces the workability of the forged gear.Four different processing paths were chosen to carry out the gear forging trials. Visual observations and metallographic examinations demonstrate that the developed workability domain contributes to optimization of forging parameters.     

基于数值模拟的模具表层温度对模具寿命的影响

模具表层温度对其寿命的影响,通过表层温度对模具硬度的影响反映出来,对钢质同步环模具进行失效分析表明,在成形过程,齿形部位剧烈的金属流动,与高压力下的热传导引起模具齿形型腔温度的快速上升,是造成模具失效的主要原因。文中对钢质同步环成形过程中模具表层温度分布规律进行了系统分析,研究了坯料温度、摩擦因子对其表层温度场的影响。结果表明,坯料温度越高,摩擦因子越大,模具表层温度上升越明显。并提出了提高模具寿命的方法。     

FE analysis on Deformation and Temperature Nonuniformity in Forming of AISI-5140 Triple Valve by Multi-Way Loading

In triple valve forming process by multi-way loading severely nonuniform deformation and temperature distributions are prone to occur, which may lead to poor forming quality and macro-micro defects. A 3D coupled thermo-mechanical rigid-viscoplastic finite element (FE) model for multi-way loading forming of AISI-5140 steel equal diameter triple valve was developed based on DEFORM-3D. Through comprehensive simulation and analysis, the influences of main process parameters on the forming process and nonuniformity of deformation and temperature were studied. The results showed that: (1) the degree of deformation nonuniformity decreased with the increase of the punch loading speed, initial temperature of billet, or the decrease of the friction factor; (2) the average temperature of forming body increased as the punch loading speed, initial temperature of billet and the friction increased, while the degree of temperature nonuniformity decreased with the increase of punch loading speed or decrease of initial billet temperature.     

基于有限元法的三通管接头多向模锻成形仿真与优化

针对三通管接头在模锻成形中易出现破裂、材料折叠、冲头载荷大等问题,研究了冲头速度、坯料初始温度、摩擦系数对锻件模锻质量的影响.通过Deform软件,研究了水平冲头和垂直冲头等速进给、水平冲头和垂直冲头差速进给、水平冲头进给而垂直冲头不运动3种工艺条件下锻件的成形规律,并基于上述最佳工艺,研究了坯料初始温度对模锻过程中温...     

台阶式凸模精冲工艺分析及数值模拟

采用平面压板的无齿圈精冲,可以有效降低模具制造成本,提高精冲材料利用率。但采用常规平面压板精冲很难获得较好的冲裁面质量。文章对常规平面压板精冲模具进行改进,通过采用台阶式凸模结构实现无齿圈精冲;采用DEFORM 2DTM软件对C20E-EN钢圆盘的台阶式凸模精冲过程建立轴对称模型进行有限元模拟,分析凸模台阶高度、台阶宽度和冲裁间隙等工艺参数对零件冲裁面光洁带高度和塌角高度的影响规律,获得了相对最佳工艺参数的配合方式。将模拟结果与台阶式凸模精冲实验结果进行比较表明,模拟结果和实验结果具有较好的一致性。     

The Effect of Temperature Condition on Material Deformation and Die Wear

The characteristics of temperature change on die and billet are very complex during the deformation process because of the interaction between them and some unstable external factors. In this paper, the numerical simulation model for the crank shaft die forging was established by means of the rigid-plastic FEM method. The model was validated by optical non-contact 3D measurement—ATOS. Based on available research results, this paper explored the effect of temperature conditions on material deformation and die wear. Three parameters, press velocity and initial temperature of billet and die, were chosen to illustrate the effects. From the experimental results, the effect of process parameters on deformation ability of the material is simple, while the effect on die wear is relatively complicated. The press velocity plays an important role on die wear when the initial temperature of the billet has larger influence on material deformation. A conclusion can be drawn that when the initial temperature of the billet is 1100 °C, the initial temperature of the die is 250 °C, and the velocity is kept in the range of 200-300 mm/s, the optimum solution for deformation ability of the material and die wear can be obtained. It is possible for the conclusion to be extended further for the control of temperature condition to optimize die life and material deformation.     

小规格TiNiNb管材的反向挤压成形工艺参数

针对44 mm×10.5 mm小规格Ti Ni Nb管材反挤压成形试验的工艺参数确定和模具设计问题,采用有限元热力耦合数值模拟和单因素轮换法,分析在满足制件成形质量(挤出温度低于共晶熔点)的前提下,挤压力与凹模模角和定径带长度、凹模和挤压筒温度、毛坯初始温度、挤压速度及摩擦因子等工艺参数和模具结构参数之间的关系,确定影响挤压力的主要工艺参数和模具结构参数分别为凹模模角、初始坯料温度、挤压速度和摩擦因子,并给出上述参数的取值范围。通过基于数值模拟的正交试验方法,得到了主要工艺参数和模具结构参数的最佳组合,即在保证润滑效果的前提下,取凹模模角110°、毛坯初始温度为950℃、挤压速度为50 mm/s。利用铅和45号钢毛坯在6.5 MN多向模锻挤压液压机上进行了验证实验。     

基于响应曲面法的波形弹簧片冲压工艺参数优化

以汽车离合器波形弹簧片作为分析对象,利用响应曲面法对冲压成形工艺参数进行优化。通过中心设计组合法及弯曲成形模具得出板料成形高度的响应值,建立了工艺参数与成形高度之间的二阶响应面模型,研究得知工艺参数对板料成形高度交互式影响的顺序依次为:弯曲半径与冲压速度、模具间隙与冲压速度、弯曲半径与模具间隙。将模具间隙、弯曲半径以及冲压速度作为设计变量,以板料成形高度作为优化目标,结合Design Expert软件对响应曲面模型进行优化,通过分析得出优化的冲压工艺参数:弯曲半径为22.13 mm,模具间隙为1.01t mm,冲压速度为2699.47 mm·s-1,成形高度的响应值为1.782 mm,经过工艺参数的修正,成形高度的试验值为1.72 mm。然而相比于正交试验得出的成形高度优化值1.65 mm,响应曲面法在波形弹簧片冲压成形工艺参数的优化中更具优越性。     

Thermo-mechanical coupled analysis of hot ring rolling process

A 3D rigid-plastic and coupled thermo-mechanical FE model for hot ring rolling（HRR） was developed based on DEFORM 3D software, then coupled heat transferring, material flow and temperature distribution of the ring in HRR were simulated and the effects of process parameters on them were analyzed. The results show that the deformation nonuniformity of ring blank increases with the increase of the rotational speed of driver roll and friction factor or the decrease of the feed rate of idle roll and initial temperature of ring blank. The temperature nonuniformity of ring blank decreases with the increase of the feed rate of idle roll or the decrease of initial temperature of ring blank and friction factor. There is an optimum rotational speed of driver roll under which the temperature distribution of ring blank is the most uniform. The results obtained can provide a guide for forming parameters optimization and quality control.