基于插装阀的液压缸试验台设计（英文）

根据液压缸的试验标准和现有液压缸试验台的不足,针对大型液压缸试验台要求高压、大流量的特点,设计出基于插装阀的液压缸试验台,并考虑到设计方便及经济型要求,提出加载液压缸和被测液压缸采用同一个液压源、高压系统和大流量系统并联的方案,减少了电机以及液压泵的使用数量,减小了系统功率,设计出一套自动化程度高,制造成本低,节能的液压缸试验台系统。     

二次增力可调立式液压缸试验台架的设计

液压缸试验台普遍不能满足高压缸的试验要求、不能满足液压缸工作状态模拟的试验要求。在不改变液压缸试验台液压系统压力的条件下,通过设计二次增力可调立式试验台架的方法,大幅度提高了液压缸试验台的试验压力,满足了立式液压缸静态或动态地模拟偏载和稳定性试验要求,同时也提高了液压缸试验台的使用寿命。     

大缸径长行程液压缸试验台设计及工程实践

依据液压缸试验标准及现有液压缸试验台存在的不足,设计出能够对最大缸径为320 mm、最长行程为1 500mm、最大额定压力为16 MPa的液压缸进行型式试验的试验台。为了减小装机功率、满足被测试缸对加载力的需求以及提高测试效率,试验台液压系统采用了高低压泵组合、比例加载系统和同步定位系统;针对不同缸径、不同行程规格的被测试缸的试验要求,设计出一种新型的液压变行程可微调定位锁紧式液压缸试验台架,并结合ANSYS软件完成了强度校验。对安装调试中出现的故障问题进行处理,并对Ф200 mm的液压缸进行测试,结果表明:该试验台设计是合理的、达到了设计要求。     

大流量安全阀动态性能试验台设计及仿真研究

新国家标准对液压支架用安全阀的动态性能的试验要求较旧标准多出了公称流量启溢闭特性试验,而目前大流量安全阀动态性能试验台大多只能对其冲击特性进行试验。因此,设计了以蓄能器快速加载为特点的大流量安全阀试验台,以满足新国家标准的要求,并采用了AMESim软件对试验台液压系统进行仿真,结果表明该试验系统的流量和压力曲线符合新标准要求。     

一种高效液压缸清洗试验机液压系统设计方案

使用在一些重要场合的液压缸,安装前除需要进行各种常规测试外,还对液压缸自身的清洁度等级提出较高要求,但普通的液压缸试验台无法保证实验液压缸的清洁度。着重介绍一种液压缸清洗试验机液压系统的设计要点,该系统充分运用电液比例自动控制,较为快捷地实现了试验压力与流量等参数的自动化控制调节,提高了设备的工作效率,最大程度地保证了实验液压缸自身的清洁度等级,提高了主机液压系统的可靠性。     

液压缸清洗试验机液压系统设计方案

使用在一些重要场合的液压缸,安装前除了需要进行各种常规测试外,还要对液压缸自身的清洁度等级提出较高要求。但普通的液压缸试验台无法保证实验液压缸的清洁度。本文着重介绍了一种液压缸清洗试验机液压系统的设计要点,该系统充分运用了电液比例自动控制,较为快捷地实现了试验压力与流量等参数的自动化控制调节,提高了设备的工作效率,最大程度保证了实验液压缸自身的清洁度等级,提高了主机液压系统的可靠性。     

液压支架高压大流量阀综合试验台设计与仿真

针对液压支架高压大流量阀设计以双蓄能器组为辅助动力源的试验台,配合增压缸实现系统的分时快速加载。该试验台可为被试阀提供近乎阶跃的短时大流量高压冲击,模拟液压支架承受严重顶板冲击的工况。基于AMESim软件搭建试验系统的仿真模型,并以FAD100/40型安全阀为试验对象,进行冲击压力安全性和公称流量启溢闭特性仿真分析。结果表明：所设计的安全阀冲击安全性试验系统能在规定时间内达到国家标准规定的阀前冲击压力;公称流量启溢闭特性试验系统提供的被试阀开启压力、流量、压力上升梯度及公称流量溢流时间均满足国家标准,进一步验证了试验台及试验方法的合理性。     

液压缸试验台自动测控系统的研制

针对目前液压缸试验装置存在的不足,设计了液压缸试验台的液压控制系统,运用C#语言进行多线程和多模块化编程,开发了基于嵌入式操作系统Windows CE的自动测控系统,实现了液压缸标准中要求的所有型式试验项目,并给出了间距便于调节的加载框架方案。工业性试验结果表明:该试验台性能稳定,工作可靠。     

液压缸综合试验台测控系统的研制

为控制液压缸产品质量,开发了精度高、功能全的液压缸综合试验台。本文介绍了液压缸试验台的工作原理,并运用MATLAB对被测缸液压系统进行了动态仿真;同时简单阐述了测控系统的硬件设计和软件开发;试验证明该试验台工作可靠,性能良好,可广泛应用于各种型号的液压缸的检验。     

高压大流量液压系统设计中的关键因素

对锻造设备中所应用到的高压大流量液压系统在设计过程中因液体可压缩性所产生的影响进行了论述,得出实际需要的流量要大于在空行程过程中的流量,在本文的实例中此数值相差高达30%以上。此外,通过阐述油液可压缩性对卸荷冲击的影响,得出在通过固定节流孔时流量和时间成线性关系,可以用来指导卸荷阀通径的选择。针对高压大流量液压系统,分析了入口节流、出口节流和溢流节流3种液压缸运动控制方式,阐明了不同的控制方式对系统的能量消耗、控制精度以及造价的影响。     

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。