高速列车制动盘盘毂锻造工艺数值模拟

基于实测的40CrA钢高温应力-应变曲线和热物性参数,建立了高速列车制动盘盘毂毛坯在模锻过程的有限元模型。运用DEFORM-3D软件,对该盘毂的多步骤锻造过程进行热力耦合模拟,得到了应力、应变和温度随时间的变化规律;研究盘毂成形过程的金属流动机制,模拟了产生折叠缺陷的位置;预测了盘毂完全成形所需的锻锤打击次数;对终锻模具的最大主应力进行分析,预测了模具在实际生产中可能产生的塌陷、开裂缺陷及其位置。根据模拟结果进行了生产试制,验证了工艺的可行性和模拟的准确性。     

汽车离合器盘毂冷精整工艺数值模拟与实验研究

提出了利用温(热)精锻-冷精整的方法生产带有异形齿法兰的汽车离合器盘毂件。针对提出工艺中的冷精整成形过程,借助数值模拟软件对冷精整成形过程进行模拟,分析了冷精整凹模的入模角α和盘毂温锻件精整余量δ对盘毂精整过程中的最大成形载荷、最大损伤值、最大径向回弹量以及齿形轴向翘曲角的影响规律。通过分析模拟结果得到,当入模角取80°、精整余量δ取0.3 mm时,可以保证轴向翘曲角取较小值时而成形峰值载荷、最大回弹量和最大损伤值取最小值。经过试验验证,盘毂温锻-冷精整工艺能够生产质量合格的盘毂产品。     

带有内法兰零件的冷模锻加工工艺

摩托车柱状转向盘零件和离合器高压轴套零件均是带有内法兰的零件,针对这两种零件现有的机械加工工艺材料消耗大、劳动生产率低的问题,提出采用冷模锻工艺加工管坯来生产摩托车柱状转向盘零件和离合器高压轴套零件的新方法,设计制造了用于标准液压机上的两种零件的冷锻模具,分析了两种零件的成形过程。实验结果证明,采用冷模锻工艺加工管坯生产带有内法兰的摩托车转向盘零件和离合器轴套零件是可行的。与机械加工工艺相比较,冷模锻工艺能够降低材料损耗50%~60%,提高劳动生产率0.5~1倍,并达到节能减排的目的。     

汽车齿轮轴闭塞式模锻成形工艺研究与试验

针对传统锻造工艺或铸造工艺生产汽车齿轮轴时效率低、质量差、寿命短的问题,根据工艺要求及齿轮轴的特征,提出了两种模锻成形工艺,即小飞边模锻成形工艺和闭塞式模锻成形工艺。通过刚塑性有限元法,利用Deform-3D软件对齿轮轴的两种模锻成形工艺进行了仿真,综合分析了材料填充规律、应力分布规律、成形力和合模力的变化规律及齿轮轴锻件的成形质量。结果显示：两种模锻成形工艺均能成形齿轮轴锻件,但是采用闭塞式模锻成形工艺获得的齿轮轴锻件的质量更好,同时也更利于模具寿命的延长。最后,通过闭塞模锻试验进行了验证,获得的齿轮轴锻件各部位均填充饱满,满足设计要求。     

两种工艺成形的ADC12铝合金连杆的力学性能对比

利用液态模锻和压铸工艺分别成形了ADC12铝合金连杆零件,借助万能材料试验机和光学金相显微镜研究了两种工艺对成形零件力学性能的影响。结果表明,利用压铸工艺虽然能实现ADC12铝合金连杆的成形,但成形零件的力学性能却较低。采用液态模锻工艺的零件不仅具有较高的表面质量,而且力学性能较高。其原因在于,采用液态模锻工艺成形的ADC12铝合金连杆零件的微观组织非常致密,几乎没有微观缺陷和偏析存在。     

基于Deform-3D的制动盘毂工艺分析

制动盘毂是高速列车上的重要零件,是典型的薄壁、宽径、深孔类复杂锻件。利用Deform-3D模拟软件对制动盘毂进行数值模拟,对成形过程的速度场、温度场．应力场,应变场及打击力进行了分析,揭示了盘毂锻造过程的成形规律。模拟结果表明,盘毂通过挤压的方式成形,连皮处温度下降严重,也是变形抗力最大的位置,最终成形结果良好,工艺方案及设备选型合理。     

推拉杆成形工艺分析及数值模拟

锤上模锻是生产杆类零件的常用方法,不仅生产效率高,并且可以得到力学性能和尺寸精度都较高的锻件.采用有限元分析软件Deform3D对推拉杆荒坯制作工艺和模锻工艺过程进行了仿真模拟,分析锻件在成形过程中的金属流动规律,提供了锻件成形过程中的温度场和速度场分布,对生产中容易出现的问题给出解决方案,确定合理的锻造工艺.模拟结果...     

钛合金斜盘模锻成形工艺

通过对钛合金斜盘的结构特点和材质性能进行分析,提出钛合金斜盘模锻成形工艺;介绍了钛合金斜盘模锻工艺流程、热处理规范以及工艺要求,并进行工艺试制和应用.实践证明：合理制定工艺流程和热处理规范、优化毛坯结构以及加强过程质量控制,采用模锻成形工艺是可以锻造出复杂、弯曲类钛合金斜盘毛坯.     

异形齿离合器盘毂冷挤压工艺优化分析与实验研究

针对某带有异形齿法兰离合器盘毂的结构特点提出冷挤压成形工艺。结合有限元分析与正交试验设计方法,以异形齿盘毂冷挤压成形峰值载荷、齿形充填情况以及最大损伤值为目标函数进行正交实验设计,并采用有限元模拟软件分析其凹模入模半锥角、凹模过渡圆角半径、坯料直径、摩擦系数和挤压速度对盘毂冷挤压成形性的影响。分析结果表明:凹模入模半锥角、凹模过渡圆角半径、坯料直径对盘毂冷挤压成形性具有显著影响,并得到最佳工艺参数组合为:入模半锥角40°、凹模过渡圆角半径3 mm和坯料直径Φ53.5 mm。工艺试验结果表明,采用优化后的盘毂冷挤压工艺可以生产出质量合格的产品。     

铝合金控制臂模锻成形工艺设计及数值模拟

控制臂作为汽车悬架系统的导向和传力元件,其锻造工艺复杂,在实际锻造生产过程中容易在零件的大拐角处出现穿透性的裂纹。该文用数值模拟预测金属成形过程,首先建立了控制臂三维数值模型,根据控制臂零件的几何形状设计了锻造工艺,然后对弯曲和开式模锻成形过程进行了分析。结果表明,该成形工艺可以较好地成形此零件,为该锻件的生产提供了理论依据。     

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.     

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。     

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.     

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.