强制循环冷却湿式气动摩擦离合制动器

强制循环冷却湿式气动摩擦离合制动器是在油浸式湿式气动摩擦离合制动器的基础上发展而成的,适用于公称力较大的高性能开式固定台压力机。 1.结构强制循环冷却湿式气动摩擦离合制动器的结构见图。离合器4和制动器5布置在飞轮3内。     

MP型热模锻压力机工作协调性的影响因素研究

在MP型热模锻压力机工作协调性研究过程中,对部分MP型热模锻压力机的使用企业进行了调研,归纳了上死点偏移、连车、闷车、停车(无动作)四种典型协调性故障,结合故障现象对应的离合器、制动器动作控制元件、凸轮控制器、进排气电磁阀、离合器制动器的复位装置,对故障进行了定位。并根据各控制元件的工作原理和结构特征采用归纳整理法进行分析研究。分析结果表明,结构与控制系统调整和环境因素为热模锻压力机的主要协调性故障影响因素,并给出了相应的对策方法。     

一种机械压力机湿式离合制动器窜油问题分析

近几年来,湿式离合制动器基本取代了干式离合制动器,在机械压力机上应用越来越广泛。湿式离合制动器具有占用空间小、制动角稳定、惯量低、噪音小、啮合／松脱速度快、环境不会受到油雾和摩擦盘粉尘影响等显著特点,且在很大程度上无需维修,减少备件并节省能耗,湿式离合制动器因上述优异特性而得到用户的一致认可。     

组合式湿式离合器/制动器在重型机械压力机上的应用

介绍了一种新型的组合式湿式离合器／制动器的结构,工作原理,并给出了湿式离合器／制动器在重型机械压力机上的具体安装调试的方法。     

人工智能方法在热模锻压力机故障诊断技术中的应用

为提高热模锻压力机生产过程中故障诊断的效率,对热模锻压力机的故障机理进行了分析;应用规则推理与案例推理的智能方法对热模锻压力机的故障诊断进行研究。结合热模锻压力机的特点并针对两种推理技术各自的局限性,提出了将规则推理与案例推理相结合的、适用于热模锻压力机故障诊断的人工智能方法;构建了热模锻压力机生产过程中故障诊断的故障树,并得到导致故障现象的最小割集;建立了表示故障案例的五元组,以离合器打滑与制动器打滑为例进行案例推理的分析。本研究在一定程度上解决了知识获取困难的问题。     

湿式组合摩擦离合器—制动器的计算及其热校核

介绍湿式摩擦离合器—制动器的摩擦材料及对冷却润滑油的性能要求、设计计算基本原理、热校核方法及其在机械压力机上的应用。     

湿式离合器/制动器及其在机械压力机中的应用

根据多年在汽车制造业中规划，使用和维修机械压力机的经验，介绍了湿式离合器／制动器在机械压力机中的应用现状及其与气动离合器／制动器在使用性能方面的比较。     

ZM—OIS 纸基摩擦材料

江苏省无锡县摩擦片厂最近研制成功一种新型摩擦材料——ZM—OIS 纸基摩擦材料,是一种湿式摩擦材料。已在压力机和工程机械的变速箱、离合器、制动器中试用,证明性能良好。具有摩擦系数大,动静摩擦系数比较接近,在离合、制动过程中比较柔和、平稳、冲击小,耐磨性能好,吸收热负荷能力强等优     

新型HFP2500热模锻压力机的设计

介绍了热模锻压力机优点、技术主参数、工作原理及结构组成,分析了机身、主传动系统、离合器、制动器、滑块和封闭高度调整系统,具有结构可靠、传动平稳、精度高等特点。     

大型机械压力机湿式离合器窜油问题分析与解决

在当前的各大汽车制造企业中,配备湿式离合器的大型机械压力机被广泛应用,湿式离合器具有控制精准、离合/制动响应速度快、传递扭矩大,且占用空间小、无粉尘及动作噪声小等特点,能够很好地满足压力机对离合器传动及控制的要求但与此同时湿式离合器也存在一些缺点,如液压控制系统较复杂,故障判断及解决较困难,尤其是窜油问题,是湿式离合器...     

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。