大过盈量联接的大型万向轴传递大扭矩的研究与设计

利用原中间轴进行万向联轴器设计,用过盈联接传递较大扭矩方法,结构简单,不需要任何紧固件,联结定心自位好,承载能力高,承受交变和冲击载荷性能好,安全可靠、满足连续生产所需要的最低寿命.中间轴与叉头热装设计,装配间隙的确定至关重要,装配间隙太大,加热包容件叉头温度过高,装配质量难以保证;装配间隙太小,装配可能失败,导致机械零件报废.包容件叉头被加热,温度曲线是一个升温、保温的过程,保温的时间比较重要.     

新式铰链联轴器

苏联第聂伯罗彼得罗夫斯克冶金学院研制了一种以圆球或鼓形滚柱为滚动体的新式铰链联轴器。这种联轴器有两种型式:一种是用于直接联接两个轴的铰链联轴器(见附图);另一种是半个铰链联轴器与法兰组成的铰链联轴器,主要用在借中间轴来联接两轴的地方,一般需由两个这佯的联轴器组成一套使用。     

摆头转台五轴机床倾斜面加工的后处理研究

针对五轴机床加工带倾斜面类零件时使用刀尖跟随功能,不能输出圆弧插补且加工时没有锁定旋转轴导致加工精度差及刚性不高的问题,采用五轴联动数控系统的倾斜面加工功能,提出了基于齐次坐标变换的后处理算法。通过在加工时将工件坐标系围绕原点进行旋转使X/Y平面与加工平面平行,然后利用齐次变换矩阵,分析摆头转台混合型五轴数控机床空间运动坐标系,并对其进行齐次变换运算得到机床运动坐标。最后,使用UG NX8.5/Post Builder编写后处理文件,通过NC代码分析、程序仿真及实际加工验证了后处理方法的正确性。     

偏心轴磨削振动分析研究

针对偏心轴在磨削过程中存在冲击和振动而影响加工表面精度和质量的问题,文章分析了偏心轴磨削系统产生的几种振动,通过CATIA三维软件建立了磨削简化模型,同时通过接口互换导入ADAMS进行运动仿真,分析研究了偏心轴磨削过程中换向冲击产生的自由振动导致的加速度曲线变化、砂轮架质量、砂轮架水平进给速度等因素对振动的影响,又分析了工件偏心、砂轮偏心引起的振动,可以为进一步提高表面质量和磨削稳定性的研究提供理论支撑。     

数控机床仿真软件二次开发的新技术

复杂自由曲面的加工,数控机床运动部件之间容易发生干涉,为了满足工程实际需要,以五轴数控加工的仿真为核心研究内容,仿真过程中结合大型UG软件强大的几何造型功能,建立五坐标机床数控仿真模型,读取数控加工的G代码,经翻译并转换为机床运动部件之间的运动,对五轴联动数控机床加工复杂零件的加工过程进行了三维仿真,动态地显示机床、工件及刀具的运动,对各个运动部件之间进行干涉检查,并进行软件二次开发,读取数控G代码指令驱动机床各轴运动,对加工过程进行动态的仿真以验证数控程序的正确性,检测加工过程中的干涉和过切,避免机床和工件的损坏,大大地提高了生产效率,降低了生产成本.     

大过盈量联结的大型万向轴传递大扭矩的研究与设计

利用原中间轴进行万向联轴器设计,用过盈联接传递较大扭矩方法,结构简单,不需要任何紧固件,联结定心自位好,承载能力高,承受交变和冲击载荷性能好,安全可靠,满足连续生产所需要的最低寿命.中间轴与叉头热装设计,装配间隙的确定至关重要.     

中间轴楔横轧成形工艺数值模拟优化及试验

楔横轧工艺是一种先进的金属成形工艺,广泛应用于成形汽车变速箱的各种阶梯轴。在成形大尺寸非对称的阶梯轴时,轧制力不平衡会导致轧制过程中轧件在水平方向窜动,台阶尺寸不稳定且出现折叠,严重时无法成形;同时,轧件在切线方向摆动量大,从而造成产品弯曲。为了解决轧件台阶尺寸不稳定及弯曲,选取一种典型的非对称阶梯轴,在断面缩减率未超过75%时,采用两次轧制,选用较为合理的成形角和展宽角,同时对料头进行限制,利用有限元模拟软件Deform模拟分析成形过程,并进行试验。结果表明:采用两次轧制能够有效平衡轧制力,保证轧件尺寸稳定;90°直角形状料头比螺旋状料头更能有效限制轧件切向摆动,防止轧件弯曲。     

基于VERICUT的异型石材罗马柱数控加工仿真

应用VERICUT及UGNX软件,对新开发的八轴双五联动数控异型石材多功能复合加工中心进行虚拟建模,并使用VERICUT软件对异型石材典型制品——罗马柱进行加工仿真研究。通过仿真检测出由UGNX软件自动生成的程序中存在的过切、干涉等问题,并对加工程序进行修改,改善数控加工工艺。通过此法不仅提高了数控机床加工功能和效率,而且降低了生产成本。     

基于动态特性分析的SG 4390型粉碎机刀架轴刀片布置设计

刀架轴不平衡会导致粉碎机在工作时出现振动,影响粉碎效果。为避免振动,降低刀架轴质量,通过调整SG-4390型塑料粉碎机刀架轴刀片放置位置,减轻了刀架轴的质量,并对改进后的刀架轴危险截面进行校核,满足要求;运用ANSYS Workbench对改进后的刀架轴进行动力学、静力学分析,得出刀架轴的动态性能与改进前几乎一致,而改进后的刀架轴消除了改进前刀架轴应力集中的现象;利用硬支撑平衡机对刀架轴进行动平衡测试,得出新的刀架布置形式并没有破坏刀架轴的动平衡。研究结果表明:此设计不仅减轻了刀架轴质量,而且使刀架轴的受力更均匀。     

斜轧机万向接轴倾角的计算与设计

万向接轴的运动原理与生产实战告诉我们:万向接轴连接角越大,其关节处的磨损越严重,尤其对于滑块式万向接轴,其磨损不但消耗有色金属,降低传动效率,而且会因磨损造成的间隙带来严重的噪音以及轧辊孔型间的相位差。此外,万向接轴的连接角大还会引起传动轴的角速度变化增大,所以在设计万向接轴时,希望其连接角尽可能小。对于一般纵轧机(如开坯机、板轧机及型材轧机等),其连接角的计算很简单,如图1     

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。