某车型侧围外板整形模具设计

侧围外板是汽车的核心外覆盖件,其特点是形状极其复杂,工序内容繁多,且零件的表面质量和尺寸精度要求较高。本文通过侧围外板的冲压工艺方案分析,提出一种内嵌压料芯的整形工艺和结构,可有效解决内部或边角整形无法压料引起的整形起皱、回弹,同时达到保证零件形位公差的目的。重点讲述了侧围整形模结构、压料芯内嵌整形机构及工作原理。实际生产表明,该结构可有效解决整形起皱、回弹,提升A面品质,缩短调试周期,降低工装开发成本。     

带大型旋转斜楔在顶盖外板侧整形模具中的应用与研究

本文介绍了一种带大型旋转斜楔在顶盖外板侧整形模具中的应用与研究,通过在顶盖外板侧整形模具上采用大型旋转斜楔解决顶盖与前风窗玻璃搭接区域负角整形,实现凸模滑块放取件与侧整形状态切换,有效缩短了模具长宽方向上的工作行程,同时实现了弧形边侧整形过程料流可控,达到零件面差精度和外观质量要求。实际生产表明,该结构可有效解决整形起皱、回弹问题,有效降低模具尺寸,节约工装开发成本,缩短调试周期。     

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。     

汽车侧围外板A柱拐角起皱的分析及解决方案

汽车侧围外板零件是车身重要的冲压件之一,成形过程较复杂,拉深过程中易产生起皱、开裂等缺陷。针对汽车侧围外板A柱拐角部位的起皱、开裂问题,通过分析零件现场冲压工艺、A柱拐角部位变形特征和材料发生起皱的原因,建立有限元仿真模型,使用AUTOFORM模拟软件对原冲压工艺方案进行全程仿真,分析结果表明,在第3工序侧整形时拐角处的流水槽面发生严重起皱缺陷。系统研究了二次拉深工序中增加吸料筋和调整压边力对起皱、开裂的影响规律,并提出在侧围外板A柱拐角处增加吸料筋和调整压边力的整改方案。经现场生产验证了分析结果的准确性和修模方案的有效性。     

汽车车门内板冲压工艺方案及修边整形模设计

介绍了一种汽车车门内板冲压工艺方案,以及上模带双模腔特征、多压料芯结构的轿车车门内板修边整形模的应用,通过对车门内板冲压工艺及模具结构分析,采用拉深后先整形再周圈修边的工艺方案,并结合CAE仿真模拟分析进行产品结构及工艺模面优化,有效解决了成形开裂及起皱问题。在修边整形模中,采用内外双排侧销控制的内压料芯及左/右外压料芯结构,使待整形区域整形时两侧同时压料,整形时发生胀形及加工硬化,在产品形状实现的同时,也可促进产品周圈刚性的提升,减少回弹变形。实际生产证明,该冲压工艺方案有效可行,已实现大批量生产,车门内板单件精度、品质及包边总成效果都较好。     

夹料翻边及整形调试方法

夹料翻边及整形工艺是模具制造过程中重要的工艺方法,这种工艺方法在顶盖天窗、门外板及侧围等汽车大型外覆盖件模具中使用较为广泛;对改进产品回弹和面品质量有较大的提升作用,通过调整夹料间隙的方式方法来改善外板回弹及面品质量有较为显著的效果。     

侧围外板起皱分析及模具改进

针对某款轿车的侧围外板暴露面起皱的问题,分析其产生起皱的原因,对制件和冲压模具工艺及模具结构提出了改进可行分析,并实施措施,应用在生产现场,从而彻底消除侧围外板暴露面起皱现象。     

侧围外板顶盖搭接处冲压新工艺的应用

侧围外板是白车身制造过程中的关键,探讨合理的工艺方案可以避免产品A面产生二次冲击线,减少焊接边翻边整形时起皱叠料现象,确保产品料边稳定一致,保证产品质量。     

轿车侧围外板表面起皱现象的工艺改进

针对上海大众汽车普通桑塔纳轿车的侧围外板暴露面起皱的问题，分析其产生起皱的原因，对原模具结构和冲压工艺提出了改进方案及实施措施，应用在生产现场，从而彻底消除侧围外板暴露面起皱现象。     

双层滑块结构在汽车侧围外板模具上的应用

介绍了一种双层滑块及压料板带滑块在汽车侧围外板翻边模中的应用,通过对侧围外板冲压工艺及模具结构的分析,实现了侧围外板侧翻边与其他工序在同一副模具上的成形,还叙述了双侧滑块及压料板带滑块结构的工作原理,该结构降低了模具的开发成本,节省了冲压车间场地的占用面积,提高了工作效率。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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.