基于FASTAMP汽车减震器钣金件冲压工艺及拉延模设计

以某型号汽车减震器上的钣金件拉延成形过程分析为例,对该钣金件的冲压成形过程进行模拟分析。借助于FASTAMP分析软件对汽车减震器上钣金件的成形过程、成形极限图和减薄率进行预测,初步估计出坯料的形状和拉延筋深度、形状等工艺参数对成形质量的影响。在此基础上对成形参数进行优化,解决了起皱和拉伸不足等缺陷。利用UG软件,设计了拉延模具中的上模、下模及压边圈等结构。     

某汽车零件的拉延工艺与模具设计

从汽车零件的材料、结构尺寸及精度等方面分析了零件冲压成形的可行性,确定了该零件的冲压工序及工艺方案。重点分析了零件的拉延工艺,根据零件的具体要求,设计了拉延工艺补充和拉延筋。利用Fastamp软件对拉延成形过程进行有限元模拟,验证了拉延工艺补充设计的合理性。在确定好的拉延工艺补充的基础上,利用Siemens NX 10.0软件,设计了拉延凸模、凹模结构和整副拉延模具的装配结构,得到了拉延凸模、凹模的工程图和整副拉延模具的装配工程图。     

基于Fastamp可成形性分析的汽车拉延件模具设计

以汽车拉延件为例,以"拉延件模型—工艺补充—成形性能分析—工艺优化—模具设计—模具—拉延件"为主线,利用延伸补片的方法,在不改变原片体的基础上对拉延件进行前期工艺补片处理,优化拉延成形时工件的分模线。根据成形情况自行设定坯料轮廓线,设计拉延件冲压工艺条件。利用Fastamp软件进行拉延可行性(成形时起皱、拉裂、应力分布、厚度改变等情况)分析,初步研究拉延件的成形缺陷,提出工艺优化措施,并总结拉延件模具智能设计过程中不同问题的解决方法,快速准确生成拉延模。     

高强度钢板梁类件拉延工艺补充及成形参数优化

针对高强度钢板汽车防火墙横梁拉延成形过程存在的拉裂、起皱等问题,提出了一种具有平缓特征的工艺补充面设计方法。应用三维CAD软件对工艺补充部分进行了优化设计,并建立了横梁拉延成形模拟的有限元模型。利用DYNAFORM软件对其拉延过程进行了模拟,分析了板料尺寸、拉延筋的分布、压边力大小、凹模上圆角大小等参数对高强度钢板横梁拉延成形的影响。模拟结果表明,平缓特征的工艺补充面改善了横梁拉延成形时板料成形状态,横梁在拉延成形过程中未出现拉裂、起皱等缺陷,成形后板料最大变薄率在30%以内,满足生产工艺要求。生产实践验证了该拉延工艺的可行性。     

轿车后地板纵梁冲压工艺分析及拉延模设计

轿车后地板纵梁形状复杂,难以掌握冲压变形规律。通过对左纵梁零件工艺分析,确定了零件的冲压工艺方案。基于Dynaform软件,对零件成形工艺进行了分析,预测了板料成形过程中的开裂与起皱缺陷,提出增大圆角半径和添加拉延筋的措施。利用UG软件,设计了拉延模具中的上模、下模及压边圈。通过实际调试,生产出合格的轿车后地板纵梁零件,最终验证了拉延模具的合理性。     

基于正交试验的拉延筋阻力优化

针对某汽车骨架件结构特点确定了一模两件的成形方式,利用Dynaform有限元软件对其拉延成形过程进行了分析。结果表明,当调整压边力不能有效提高成形质量时,设置拉延筋能改善成形质量。基于正交试验法重点研究了拉延筋设置对冲压成形质量的影响,依据正交试验数据反映出的优化方向,对各段拉延筋阻力和数量进行了优化,使成形质量满足设计要求。研究结论对工程应用具有指导意义。     

基于Dynaform的某汽车外板件拉延分析与模具设计

详细分析了某汽车外板拉延件的成形工艺,利用Dynaform分析软件对拉延件的成形过程进行数值模拟,获得了坯料流入量分布、拉延结果、板料厚度变化及FLD图等模拟结果.通过对模拟的结果分析,提出了减少成形缺陷的措施.根据分析结果进行拉延模具设计,确定了拉延模具结构及压力中心,设计了上模、压边圈及下模,详细阐述了其工作原理,并进行了实际冲压试验.结果显示,借助数值模拟技术实现了拉延模的结构优化、提高了模具设计效率与可靠性,并最终通过实际实验调试获得满足质量要求的汽车外板零件.     

基于CAE分析和FLD实验的拉延模具模面优化

在汽车零部件的生产过程中,冲压模具拉延模面设计的优劣决定了冲压件的成形性、成形质量和型面尺寸精度。以我公司生产的某车型后地板左/右纵梁零件为例,零件形状复杂、拉延深度深,对拉延模具型面设计要求较高,生产中零件变截面拐角区域易出现拉延开裂现象,严重影响零件的工艺质量及生产效率。基于CAE分析,对其初始设计加工的拉延模面拉延成形过程进行数值模拟,依据CAE分析结果对零件拉延模面设计进行修改优化,得出合理的拉延模面用于模具加工制造,并通过FLD实验验证分析结果,为后续复杂零件的拉延模面设计提供参考,缩短了设计周期。     

汽车覆盖件的模面参数化设计与数值模拟

工艺补充面和压料面是汽车覆盖件拉延模型面设计的重要环节,其设计合理与否是决定拉延能否顺利成形和获得合格工件的关键.介绍了应用DYNAFORM软件中的模面工程模块实现汽车覆盖件模面的参数化设计,以仿真模拟判断模面的优劣,再根据模拟结果对模面进行快速修改.以汽车右翼子板为例,介绍了型面设计及成形性分析的过程.     

基于CAD/CAE的汽车覆盖件拉延模设计

对汽车覆盖件拉延模的设计进行了研究。以汽车发动机盖外板为例,在零件数模建立的基础上,借助拉延成形仿真对成形过程中的拉裂、起皱等缺陷进行预测,得到零件的成形极限图和厚度变化图,并依此来判断其成形效果。通过改变结构参数和工艺参数优化拉延成形方案,根据最佳的成形方案进行了拉延模结构设计。最后通过试验对设计结果进行验证,试模结果与仿真分析结果一致,零件的最大变薄率为27.5%,最大变厚率为9.5%,满足成形要求。研究结果表明,基于CAD/CAE的汽车覆盖件拉延模设计方法是可行的,能够缩短产品开发周期,提高设计水平。     

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).     

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.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

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.