夹紧刀头用的楔铁机构

图示为一种在刀杆中夹紧刀头用的楔铁机构。该机构既可以减少调刀时间又能保证刀头可靠的固紧。刀杆1上加工出相互垂直的孔,其中一个孔装有Г型楔铁3,另一个孔装有刀头2,楔铁和刀头相互作用的面作成平面。用旋进楔铁凸台的螺钉4夹紧刀头。     

刨削机床调整楔铁(镶条)的专用夹具

在机床等设备的修理中,由于调整楔铁的磨损,少不了进行重新加工或大改小的工作。为了得到与原楔铁相同的斜度,通常的方法是抱铁板覆盖在原楔铁上进行近似的加工。这样做不但很麻烦,且往往由于斜度相差太远增加刮削量,延长停修时间。为了提高加工质量,方便操作,我们制作了一套专用夹具,包括刨薄板夹具、刨斜面夹具、刨     

低速柴油机曲柄热处理变形控制研究

低速柴油机曲柄的常规热处理装炉方式为竖立式,但热处理后曲柄内档变形较大,难以满足产品后序精加工要求.通过改变曲柄的热处理装炉方式,由竖立式改为平装式,辅以垫铁和楔铁并适时调整垫铁和楔铁的位置,可有效控制曲柄的热处理变形,满足产品后续精加工要求.     

伺服滑阀建模与动态仿真

滑阀是20MN快速锻造液压机中的重要控制部件,其性能的优劣直接影响压机的稳定性和定位精度。本文通过对滑阀的受力分析建立了滑阀的数学模型,得到了伺服滑阀闭环系统的传递函数,并利用Matlab分析出滑阀的动态性能。     

高精度液压滑阀卡紧问题分析与改善

液压滑阀卡紧是液压控制系统的常见故障之一。通过对液压滑阀卡紧现象的描述及产生原因的分析,重点论述了通过优化滑阀零件的制造工艺流程减少液压滑阀卡紧现象的方法。     

数字液压缸阀芯特性研究

阀芯特性是影响数字液压缸准确性与稳定性的重要因素。以数字液压缸的滑阀阀芯为研究对象,通过建立圆柱滑阀、矩形槽滑阀和锥形滑阀3种典型滑阀过流面积的数学模型,并结合数字液压缸AMESim仿真模型对3种阀芯的特性进行对比分析,研究3种滑阀对该型数字液压缸特性的影响,为该型数字液压缸滑阀阀芯的设计、选择及优化提供了参考依据。     

橡胶履带铁齿的楔横轧制坯工艺数值模拟分析

结合橡胶履带铁齿的锻件特点,利用三维造型软件模拟出铁齿锻件形貌以分析锻件的体积分布曲线,设计出精密制坯形状,采用楔横轧精密制坯替代自由锻制坯工艺.并采用Deform-3D软件对优化设计后的毛坯进行锻造数值模拟,获得了型腔的填充性能、金属的流动情况以及锻件的应力应变状态,有效的提高了制坯的精度及尺寸稳定性、生产效率和自动化程度.优化设计后的毛坯在630楔横轧机上轧制出合格的锻件,并实现了铁齿锻件的稳定批量生产.     

橡胶履带铁齿的楔横轧制坯工艺数值模拟分析

结合橡胶履带铁齿的锻件特点,利用三维造型软件模拟出铁齿锻件形貌以分析锻件的体积分布曲线,设计出精密制坯形状,采用楔横轧精密制坯替代自由锻制坯工艺。并采用Deform-3D软件对优化设计后的毛坯进行锻造数值模拟,获得了型腔的填充性能、金属的流动情况以及锻件的应力应变状态,有效的提高了制坯的精度及尺寸稳定性、生产效率和自动化程度。优化设计后的毛坯在630楔横轧机上轧制出合格的锻件,并实现了铁齿锻件的稳定批量生产。     

射流管伺服阀滑阀形变对伺服阀性能的影响

射流管伺服阀以抗污染能力强、灵敏度高、失效对中等特点,被广泛应用于航天、航空、船舶等领域。介绍射流管伺服阀滑阀在不同工况下形变对伺服阀性能的影响,建立了滑阀摩擦的数学模型;利用有限元软件ANSYS对射流管伺服阀滑阀形变进行了静力学分析,同时结合AMESim分析了滑阀形变对伺服阀性能的影响;试验验证了射流管伺服阀滑阀在不同工况下,滑阀形变对伺服阀性能的影响,为滑阀结构设计、滑阀摩擦研究提供参考。     

基于径向热变形的滑阀滞卡数值研究

液压滑阀常常在使用过程中伴随着黏性加热现象,这将严重影响液压滑阀的控制特性。为了揭示滑阀的热失效故障,建立带有配合间隙的滑阀热特性模型,运用COMSOL软件内置的共轭传热与粒子追踪模块通过求解滑阀热特性模型,对液压滑阀内的流动与传热过程进行数值解析。结果表明:高温主要出现在速度梯度较大的区域以及受高速油液冲击的节流槽壁面;由此导致滑阀配合边上产生不均匀径向热变形,固体颗粒物在发生变形的间隙更容易聚集,由此可知,滑阀配合边的径向热变形对颗粒物的污染卡紧有促进作用。这些研究成果为工程技术人员对液压滑阀卡紧现象提供可视化的理解。     

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.     

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.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。