前滑块锻造工艺分析及数值模拟

分析了前滑块锻件工艺方案及关键技术特点,制定了前滑块预锻、终锻成形工艺方案,采用DEFORM-3D软件对成形过程进行了数值模拟.通过比较分析最终确定了前滑块预锻、终锻的最优方案.模拟结果显示,只有合理地选择坯料形状、制定工步,才能顺利地成形锻件.     

大型曲臂锻件模锻成形工艺模拟研究

针对大型曲臂锻件的结构特点和性能要求,提出采用了预锻-终锻两步成形方法模锻成形大型曲臂锻件。采用DEFORM-3D有限元软件对此工艺方法的成形过程进行模拟,并对应力、应变、温度场的分布特点和时间-载荷曲线进行分析。结果表明,采用此方法能够在8万吨水压机上饱满成形大型曲臂锻件,得到金属流动合理、锻造流线完整的锻件。     

弧齿锥齿轮小轮热滚轧成形工艺的数值模拟研究

采用有限元软件DEFORM-3D对弧齿锥齿轮小轮的热滚轧过程进行模拟,并对弧齿锥齿轮小轮热滚轧工艺进行了分析。模拟结果说明,该滚轧成形工艺可行。通过滚轧成形过程中等效应变场、等效应力场、温度场及载荷-行程曲线等物理量场的分析,获得了滚轧成形的工艺参数。     

汽车离合器衬套多道次工艺设计与仿真

针对所研究的离合器衬套的特点,设计了整个工艺流程,包括落料、拉深、胀形、冲锻复合成形、冲孔和修边,其中通过多模块胀形工艺成形零件周向均布的36个齿槽,通过冲锻复合成形工艺实现零件底部的壁厚变化,重点分析了胀形工艺和冲锻复合工艺的实现过程.采用有限元软件DEFORM-3D模拟整个工艺过程,模拟结果表明:胀形工艺能够完整、准确地成形出零件周向均布的齿槽,冲锻复合成形工艺成功实现了零件底部壁厚的变化,整个工艺流程切实可行.     

DEFORM-3D仿真软件在连杆锻造过程中的应用

分析连杆锻造过程中的参数选择,利用有限元仿真软件DEFORM-3D实现连杆锻造成形整个过程的数值模拟,在应力、应变分布、载荷计算、材料流动速度、模具填充和毛坯优化等方面做了深入研究,为模具及成形设备的设计提供了可靠的依据。     

汽车离合器衬套多道次工艺设计与仿真

针对所研究的离合器衬套的特点,设计了整个工艺流程,包括落料、拉深、胀形、冲锻复合成形、冲孔和修边,其中通过多模块胀形工艺成形零件周向均布的36个齿槽,通过冲锻复合成形工艺实现零件底部的壁厚变化,重点分析了胀形工艺和冲锻复合工艺的实现过程。采用有限元软件DEFORM-3D模拟整个工艺过程,模拟结果表明：胀形工艺能够完整、准确地成形出零件周向均布的齿槽,冲锻复合成形工艺成功实现了零件底部壁厚的变化,整个工艺流程切实可行。
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板式翅片滚压成形过程仿真

采用一种新型滚压工艺进行板式翅片加工,简述了板式翅片的成形原理及滚压刀具的设计原则;利用DEFORM-3D软件对其成形过程进行模拟仿真,获得了理想的模拟翅片结构;分析了成形过程中工件的应力应变状态和滚压刀具在成形中的受力状况,通过加工实验验证了该方法的可行性。     

基于DEFORM-3D的花键成形分析

基于刚塑性有限元法基本理论,并借助于通用三维有限元分析软件DEFORM-3D建立了花键冷滚压成形全过程三维动态有限元模型,对花键冷滚压成形过程进行了有限元模拟分析。揭示了花键冷滚压成形过程的等效应力、等效应变的分布情况和金属流动规律,从而为花键冷滚压成形工艺研究提供理论依据。     

以DEFORM-3D实现花键轴精密冷滚轧成形模拟

使用有限元仿真软件DEFORM-3D,实现渐开线花键冷滚轧成形整个过程的数值模拟;针对金属大变形问题,DEFORM-3D提供了一个全自动的、优化的网格再划分功能,为充分利用此功能,采用间接方法实现渐开线花键冷滚轧成形过程的数值模拟,并对成形过程中工件与模具之间的相互关系、成形力和变形特点进行分析与研究,为模具及成形设备的设计提供了可靠依据.     

基于DEFORM的大型封头整体锻造工艺数值模拟

大型整体封头越来越受到重视,需要开发可行的制造工艺。通过采用数值模拟的手段,设计了采用上模和下模的整体封头锻造工艺,对两种上模旋转下压的方式进行了对比,通过DEFORM-3D塑性成形软件对锻造过程进行了模拟计算,分析了终锻后锻件的等效应变分布。结果表明,通过采用上模旋转下压的方式,可以得到所需的封头,锻件尺寸符合要求。     

BT25钛合金动态再结晶行为的元胞自动机模拟

为研究热加工工艺参数对钛合金塑性成形过程中微观组织的影响,利用Gleeble-3500型热模拟试验机对BT25钛合金进行单道次等温恒应变压缩试验。分析真应力-应变曲线,建立JMAK动态再结晶动力学方程;通过对热变形行为的分析,推导出钛合金的位错密度模型、再结晶形核和晶粒长大模型;结合元胞自动机的算法,建立元胞自动机(Cellular automata, CA)模型并利用该模型模拟和验证了BT25钛合金热变形过程中动态再结晶行为。结果表明,BT25钛合金的流动应力对应变速率和变形温度非常敏感;提高变形温度或降低应变速率均有利于材料发生动态再结晶;CA模型模拟晶粒尺寸误差约为3%,预测DRX体积分数误差在10%以内。该模型具有良好的预测精度,为合金材料在塑性加工过程中优化工艺参数和控制锻件微观组织演变提供了可靠性依据。     

Numerical modeling of dynamic recrystallization during nonisothermal hot compression by cellular automata and finite element analysis

In this study, dynamic recrystallization during nonisothermal hot compression was numerically simulated by cellular automata and finite element analysis. A modified cellular automata model was developed by introducing a new parameter for considering solute drag effect. The isothermal hot compression tests of pure copper were carried out to verify the modified cellular automata model by comparing material behavior and average grain size. The effect of solute drag was numerically considered and compared to the experimental data and the numerical data obtained by conventional cellular automata without solute drag effect. Then, the modified cellular automata model was applied to a nonisothermal hot compression by combining with a finite element analysis. The finite element analysis was conducted to acquire local parameters such as strain, strain rate, and temperature. These values were provided to the cellular automata model as input. The local changes of microstructure and average grain size were simulated by cellular automata and compared with nonisothermal hot compression results. The simulation results were in reasonably good agreement with experimentally determined microstructures by electron backscattering diffraction. The developed model was further applied to simulate a hot gear blank forging process to check its applicability. With the current approach, local microstructures can be determined for better understanding microstructural changes during the nonisothermal process.     

热带钢连轧多场耦合演变过程有限元分析

根据物理冶金组织演变规律和经验公式，开发了金属热变形过程耦合组织演变的计算模块。结合某厂2050热带钢连轧工艺过程，利用非线性刚塑性有限元法，建立热连轧过程热、力、组织的多参量耦合仿真模型。运用该模型对2050现场实际轧制过程进行模拟计算，分析了轧制过程轧件变形场、温度场及显微组织的演变规律。模拟得到的轧制力能参数、温度、组织分布与实测数据基本一致。     

连续 ECAP 大应变的数值模拟研究

基于刚塑性有限元理论,采用有限元软件DEFORM-3D对5052铝合金连续ECAP(Equal Channel Angular Pressing)大应变成形过程进行了三维数值模拟研究,研究了工件的变形过程以及应变均匀性,温度的分布规律。模拟结果表明,金属变形剧烈部位主要集中模具的拐角区域,该区域的等效应变呈层状分布,而且变化梯度较大并且温度最高。模拟结果对实际生产具有很好的指导作用。     

20CrMnSiNi2MoA凿岩用钢等温自由锻模拟及试验研究

针对凿岩钻头用钢20CrMnSiNi2MoA,基于JMatPro软件模拟计算材料的应力应变曲线,并线性回归出材料的流变应力方程;基于DEFORM-3D有限元软件对材料进行了不对称V型砧锻造法等温自由锻造压缩,并预测了微观组织变化趋势。研究结果表明：原始奥氏体晶粒随着压缩量的变大,发生了动态再结晶,晶粒尺寸得到细化;温度一定时,随着变形速率的提高,晶粒平均尺寸变小。将通过不对称V型砧锻造法等温自由锻及热处理得到的钻头成品的机械性能与国外同类产品的机械性能进行了对比。     

Study on forming defects in the rolling process of large aluminum alloy ring via adaptive controlled simulation

According to the distribution characteristics of equivalent plastic strain (PEEQ) in radial?Caxial ring rolling, the plastic deformation zones in cross section were established. A 3D rigid-viscoplastic finite element model (FEM) which was controlled adaptively was applied to investigate defects that occurred during ring rolling under ABAQUS software. PEEQ, stress, and temperature distributions in different deformation zones have been analyzed in this study. Strain peaks were found in the cross-section corners. Moreover, it was investigated that non-uniform strain, stress, and temperature distributions in the ring tend to cause non-uniform microstructure and properties. Therefore, forming defects and microstructure damage would appear in cross-section corners due to the high-strain deformation. Based on the new developed FEM of the radial?Caxial ring-rolling process and comprehensive numerical simulations, the size effects of feed rate and lubrication conditions on strain and temperature distributions and their uniformity were investigated by 3D coupled thermomechanical FE simulation. The results have good agreement with experiment. The achievements of this study can provide basis for quality control and technical guidance.     

Multi-filed coupling numerical simulation and experimental investigation in electromagnetic riveting

In this work, electromagnetic riveting (EMR) of aluminum alloy rivet was investigated by numerical simulation and experiments. The numerical simulation was carried out by means of ANSYS and LS-DYNA software. The SPHB (Split Hopkinson Pressure Bar) test was performed for 2A10 aluminum alloy rivets, and Johnson-Cook material model was used to describe it. The sequential electromagnetic-thermal-mechanical coupling model was established to analyze magnetic pressures, adiabatic temperature rise, and deformation process. Experiments and microstructure observation were performed to verify the proposed model. The formation of adiabatic shear band and the effective strain distribution were simulated, and the maximum temperature rise was up to 252 °C. The dynamic recrystallization was observed by optical microscopy observation under a discharging voltage of 2.0 kV. The simulation result of rivet heading accorded with experiments.     

Static recrystallization simulations starting from predicted deformation microstructure by coupling multi-phase-field method and finite element method based on crystal plasticity

We have developed a numerical model of recrystallization taking the inhomogeneities of the plastic deformation of a polycrystalline metal into account. Here, the plastic deformation of the polycrystalline metal is simulated by the finite element method based on crystal plasticity theory and the microstructure evolution during recrystallization is simulated by the multi-phase-field method. In primary recrystallization simulations, nucleation is the most difficult problem. In the present model, the deformation microstructure is predicted from the results of a crystal plasticity finite element simulation, and spontaneous nucleation is achieved through abnormal grain growth that is enabled by introducing the misorientation dependences of grain boundary energy and mobility. As a result of simulations under three different compression strains, it is confirmed that primary recrystallization simulations depending on the amount of deformation and taking the inhomogeneities of the plastic deformation of a polycrystalline metal into consideration can be successfully performed by employing the proposed model.     

Microstructure analysis of aluminum extrusion: grain size distribution in AA6060, AA6082 and AA7075 alloys

Microstructure and material flow of aluminum alloys have a significant influence on the mechanical properties and surface quality. In extrusion of aluminum billets at high temperatures the microstructure is dependent on the alloy and the forming and temperature history. A prediction of grain size and precipitation is of increasing importance in order to design the process by adjustment of parameters such as punch speed, temperatures, and quenching. To give references for microstructure prediction based on material flow, and with it strain and strain rate history, this paper deals with the microstructure during the extrusion process of AA6060, AA6082, and AA7075 alloys. Billets have been partly extruded to axisymmetric round profiles and the microstructure of the press rests consisting of the billet rests in container and die has been considered. Furthermore, these rests have been analyzed to show the material flow, dynamic and static recrystallization based on macro etchings and visible microstructure under different conditions, e.g. as in the area of high strain rate near the container wall, or in dead zones [1]. To allow an accurate simulation of the extrusion process, punch force and temperature conditions during the tests have been measured and are presented in this paper, too.     

3D FEM simulation of milling process for titanium alloy Ti6Al4V

Milling is used as one of the most important tools with the complex tool geometry in industry. However, the complex milling process cannot be simulated by 2D finite element method. Therefore, a more real 3D finite element model (FEM) for the complex milling process of titanium alloy Ti6Al4V is firstly developed using the finite element software ABAQUS. This model takes into account the dynamic effects, thermomechanical coupling, material damage law, and contact criterion. Firstly, the Johnson–Cook material constitutive equation was proposed, considering the effects of strain, strain rate, and temperature on material properties. Secondly, the damage constitutive law was adopted as the chip separation criterion. Then, the simulation for the milling process of Ti6Al4V was conducted through ABAQUS based on the established 3D FEM. Finally, chip formation, stress distribution, cutting force, and milling temperature were obtained. Further, a series of milling experiments of Ti6Al4V were carried out to validate the simulation results. It confirms the capability and advantage of 3D FEM simulation in the complex milling process of titanium alloy.