提高电弧喷涂层与基体结合强度的新工艺

介绍一种新型电弧喷涂技术--粉末复合电弧喷涂技术。运用粉末复合电弧喷涂技术对轴类零件和轴承座内孔进行喷涂。在喷涂前,对轴类零件粗车螺纹并进行挤压,使基体表面形成钩子形状,增加喷涂层和基体的机械结合力;对轴承座内孔进行堆焊,将大表面分割成小表面,减少了喷涂层收缩时形成的裂纹,提高了喷涂层与基体的结合强度。这两种方法适合大型轴类零件的表面强化和修复。     

轴类零件校直机液压及 PLC控制系统设计

轴类零件校直机是轴类工件热处理后不可缺少的修整设备.介绍轴类零件校直机的基本结构、液压系统及其工作原理.根据校直机的工作要求,设计了基于PLC的控制系统.实践表明,采用PLC控制系统提高了校直机的性能和工作稳定性.     

轴颈珩磨头的研制

本文介绍了一种可提高大型轴承类零件表面粗糙零件粗糙和几何形状精度的珩磨头装置，对珩磨头的设计原理、结构特点和使用方法做了较为详细的论述，该装置的研制成功对提高轴类零件的加工精度和产品质量具有很好的实用价值。     

细长轴类零件径向圆跳动测量数据处理方法研究

基于激光位移传感器三角测量技术,利用摩擦结构驱动轴转动,结合PLC对测量数据进行处理,在线实现细长轴杆类零件径向圆跳动测量。经试验测试,测量精度可达0.05mm,满足中小直径轴类零件的非接触式测量要求。     

积放悬挂链式热处理生产线的特点与应用

目前国内轴类零件的热处理普遍使用井式炉、台车炉等周期式电阻炉，生产效率低，能耗大，自动化程度低，人为因素影响大，质量不稳定。积放悬挂链式热处理生产线是一种新型的集装卸料、加热、冷却工艺为一体的可连续生产的智能化控制的大型工艺装备。主要用于大型轴类零件(如火车轴)的批量正火、回火热     

柔性光纤激光熔覆加工研究

大型模具表面硬化和大型异形件表面修复,历来都是一个难题。利用六轴机械手柔性系统和光纤传导大功率激光柔性系统,可将高功率激光束传输到复杂曲面各加工点的法向方向,并聚焦在复杂工件表面,能大大提高激光表面加工的精准度和质量,满足大型异形件表面激光淬火和激光表面熔覆加工的需求。介绍了六轴柔性光纤激光熔覆加工机的开发背景、技术原理、开发研究内容、产品架构及其创新性研究工作的意义。     

30CrMnSi轴表面激光相变硬化温度场数值模拟研究

根据激光相变硬化的特点,建立了轴类零件移动激光热源作用下三维激光相变硬化温度场计算模型,利用有限元软件ANSYS对30CrMnSi钢轴件温度场进行了数值模拟.得到轴件激光相变硬化的温度场和距轴表面不同深度的热循环,并根据模拟结果预测了轴件相变硬化层的深度和宽度.     

大型轴类锻件矫直机液压系统的设计与分析

重型机械中的轴类零件在高温锻造后需要进行矫直处理,以满足实际使用要求。综合现有的机械矫直和检测方法,设计大型轴类零件矫直设备的主机和液压控制系统。介绍矫直设备的结构及工作原理、矫直机的数控系统和控制方案;提出矫直、检测、清理氧化层的液压控制方案,并且对检测系统的稳定性进行理论分析和AMESim仿真,最后分析了矫直机的伺服系统,它提高了矫直机的精度。该矫直机设计有氧化皮清理机构,提高了矫直和检测的精度,减小了误差,检测矫直处于同一工位并形成反馈系统,提高了生产效率,为大型轴类零件的矫直提供了一种实用高效的新方法。     

基于PLC的积分分离PID控制系统在精密校直液压机中的应用

针对管类、轴类零件校直校平的工艺要求,提出一种基于PLC的积分分离PID控制算法,其中PID控制算法通过PLC来实现,执行机构采用高频响伺服系统。实践结果表明:该系统响应速度快,超调小,校直精度和重复定位精度高。     

轴类零件激光校直试验研究

为了研究轴类零件激光淬火工艺校直的可行性,以及不同工艺条件下校直的效果,设计了轴类零件激光淬火校直试验。采用CO2激光器对阶梯轴不同位置进行激光淬火,通过改变淬火面积、轴径大小、激光功率、扫描次数等工艺参数,定性分析不同加工工艺对轴类零件校直效果的影响。结果表明,轴类零件采用激光淬火的方法能够校直,弯曲轴最大可校回量为0.1 mm,工艺参数中淬火面积和轴径大小对校直效果影响很大。     

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.     

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。     

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).     

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.     

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.