某车型侧围外板冲压工艺分析及整形模设计

介绍了某轿车侧围外板冲压工艺及整形模设计,从确定冲压方向及拉深深度、避免产生滑移线和冲击线的方法与措施、拉深筋的设计注意事项、CAE模拟等几方面进行了分析,并结合前期车型设计和生产的经验总结,对侧围外板侧整形模结构进行了优化,侧围外板整形模成形零件质量有明显的提高。     

轿车侧围外板冲压成形分析

侧围外板是轿车覆盖件中最复杂、模具调试周期最长的零件.分析了某车型侧围外板的拉深件成形过程,并结合有限元模拟,探讨了实际生产调试过程中出现的开裂部位、起皱部位、滑移线以及面畸变缺陷等问题,并给出了调整处理办法和解决方案.通过数值模拟,准确地预测成形缺陷,对侧围模具的调试优化工作具有实际指导意义.     

斜楔在解决二次冲击痕中的应用

对某车型的行李箱外板进行了CAE模拟,预判了该零件在实际生产中产生二次冲击痕的风险,通过利用斜楔成形结构,弥补了常规工艺方法在解决二次冲击痕的缺陷,使行李箱外板的二次冲击痕显现区域完全控制在R角范围内,对其他车型的行李箱外板成形有一定的参考作用。     

汽车侧围内板冲压成型技术仿真与应用

针对某车型侧围内板在试模阶段出现的样件品质不良,采用板料维成形分析软件AUTOFORM对其拉深成形过程进行了数值模拟.主要研究了不同工艺补充对零件冲压成形的影响,通过试模样件和CAE仿真成形结果的对比,对工艺补充部分进行调整,得到了最优化的拉深件型面,并生产出质量合格的产M,为类似零件的生产起到了指导作用.     

基于伺服技术的侧围外板材料降本方案

为了降低侧围外板材料成本,运用AutoForm软件对侧围外板拉深成形过程进行了数值模拟,研究了侧围外板成形过程中塑性变形与压边力加载方式和冲压速度的关系。当压边力和冲压速度呈阶梯式从大到小变化时,侧围外板能获得最佳的成形效果。通过将数值模拟与伺服技术相结合的方式,对侧围外板拉深成形速度曲线进行优化,实现了侧围外板材料从JAC270F-45/45到JAC270D-45/45的降级。结果表明,运用伺服技术后,材料切换为JAC270D-45/45的侧围外板成形良好,能满足侧围外板批量生产需求,可为整车节约制造成本52.6元/台。     

SUV车型侧围外板冲压工艺的数值模拟分析

以某SUV车型侧围外板零件为例,采用Autoform数值模拟软件对侧围外板零件的结构特点和冲压成形工艺进行分析,重点论述了其流水槽区域、门框区域、后保搭接区域和尾灯区域的冲压成形;预测了可能出现的成形缺陷并制定了合理的冲压工艺方案。分析结果表明,侧围外板流水槽区域、门框的A柱部位、尾灯区域存在起皱现象,后门框的圆角部位和后保搭接区域存在开裂风险;采取加大开裂处的模具圆角、调整压边力和改变加强筋长度等措施,对成形工艺进行了优化。试制结果表明,采用优化后的冲压工艺可以有效预防侧围外板零件的起皱、开裂缺陷。     

一种侧围A柱起皱的原因分析和解决办法

<正>侧围外板是影响车身品质的关键冲压件之一,侧围A柱上端起皱问题长期影响着侧围外板成形质量。本文基于某车型产品结构设计和实物状态的研究,结合CAE数值模拟与分析,对侧围外板A柱上端起皱问题进行了系统地原因描述,并给出改进方案和现场验证。     

一种提升汽车覆盖件材料利用率的方法

在多款车型实践基础上,总结了一种提升汽车覆盖件材料利用率的方法,给出了工作流程图,即在同步设计开发或油泥车阶段,应用板料成形CAE模拟手段,通过优化零件边界、工艺补充面、坯料形状的交互试错,获得了优化的零件状态和合理的工艺方案,实现了材料利用率的最优化;以B车型的轮罩外板零件为实例,采用上述方法可将该零件的材料利用率从38.04%提升到56.67%,每台节省材料3.61 kg、实现效益22.96元,证实了该方法有效可行。     

侧围外板门洞起皱的解决措施

针对侧围外板门洞褶皱产生的原因进行分析,通过CAE软件模拟验证零件成形工艺更改方案并在模具上实施整改,最终消除缺陷,从零件、工艺、调试等方面总结了有关门洞起皱问题的解决措施。     

汽车侧围外板表面缺陷分析及冲压工艺优化

汽车外覆盖件的表面质量直接影响整车的外观,是冲压成形领域关注的重点之一。针对SVW斯柯达品牌某车型侧围外板在冲压成形过程中出现的开裂、起皱、圆弧轮廓不平顺等一系列表面缺陷,从工艺设计和模具结构的角度分析了缺陷产生的原因。结合CAE模拟和现场调试,在满足试模压机和生产线压机不同工况的条件下,通过优化产品表面藏料工艺凸包,同时平衡压料力和整形力,解决了最困难的表面问题,达到了生产稳定性和产品质量的要求,并在此基础上,对工艺优化产生的经济效益进行了统计。对汽车行业侧围外板产品的零件设计、侧围冲压模具工艺和结构设计、侧围冲压模具调试均具有参考意义。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.