电动汽车真空助力制动系统的匹配优化方法研究

针对电动汽车制动系统的真空助力系统参数进行匹配与优化,设计了匹配与计算流程,建立了制动系统的数学模型,提出了真空泵抽气速率、真空罐体积和启停真空度等真空助力系统参数的优化方法。以电动中巴为例,匹配计算制动系统所需的最小真空度及真空泵抽气速率,分析真空罐体积与抽气速率的关系;通过建模仿真,分析启停真空度与抽气速率、工作时间和能耗的相互影响。结果表明:真空罐体积为5 L、真空泵抽气速率为18 L/min、启停真空度为45~65 k Pa时,真空助力系统的综合性能最优。     

非摆线型采油螺杆泵转子复合加工机床研制

针对现有双头螺杆泵转子线型存在的问题以及加工方法的局限性,通过研究非摆线螺杆泵转子线型形成原理,设计了非摆线型采油螺杆泵转子复合加工机床,利用立铣刀对做行星运动的工件进行包络,加工出非摆线型螺杆泵转子。根据机床的机械结构以及转子加工表面的形成运动,对转子加工机床进行了运动分析,确定了机床各轴之间的运动关系。并分析立铣刀在加工转子时所产生的截面轮廓误差,确定了误差随工件自转转速变化的关系,对非摆线型螺杆泵转子的加工提供了参考。     

基于图像深度信息集的Hough圆检测方法

针对利用视觉引导的工业机器人进行轴孔装配,提出了一种基于图像深度信息集的工件圆孔检测方法,对三轴磁流体密封装置上的轴承孔进行了边缘特征提取和检测实验。首先利用3D相机采集对齐的三轴磁流体密封装置的彩色和深度数据流样本,根据待检测轴承孔所在平面的深度信息提取出该轴承孔在深度图像中的所有像素坐标。然后对彩色图像矩阵进行相应的数据处理,再经霍夫圆变换即可检测出该轴承孔的相关参数信息。实验结果表明,基于图像深度信息集的霍夫圆检测克服了传统霍夫变换无法单独识别特定的圆以及复杂背景下的错检和漏检等缺点,对复杂情况下的工件圆孔识别和检测具有一定的指导意义。     

消失模铸造中真空泵及真空度和铸件质量

介绍了在消失模铸造中，真空泵的正确操作方法，分析了真空度与铸件质量的关系。     

球铁真空泵转子铸造缺陷的焊补

球墨铸铁真空泵转子较为厚大,在铸造生产中极易产生缩孔缺陷.本文对球铁真空泵转子缩孔缺陷的焊补工艺进行了研究,通过试验确定了缺陷焊补工艺,解决了球铁真空泵转子缺陷的焊补问题,提高了成品率.     

铝电解增效节能从设计抓起

本文详细介绍了电解槽磁流体设计理念，利用先进的磁流体分析软件，对NEU1400型电解槽进行了全面磁流体分析。模拟结果表明，在正常生产及工艺操作后，NEU1400电解槽均可以稳定运行。磁场测试结果与模拟结果非常吻合，表明了模拟结果的可靠性。     

水蒸汽喷射真空泵

水蒸汽喷射真空泵是以水蒸汽为工作动力的喷射型真空泵。与机械真空泵相比具有很多优点:抽气量大;工作真空度宽(1.33Pa～10~5Pa);结构简单、无相对运动部件,操作维护方便,工作寿命长,造价低;特别适合用来抽除含尘、含水汽、腐蚀气、易燃气的气体。广泛用于冶金钢包真空精炼、石化真空反应、聚合、脱水,食品、药品真空浓缩、冷冻升华,机械真空热处理,真空制冷等。本所的产品能耗指标已达到国际先进水平,可根据用户要求承担设计、成套和供货。可向钢     

大型汽轮机实心转子超声波检测研究

本研究利用一根存在大量各类冶金缺陷的小型实心转子作为参照平台 ,模拟大型汽轮机实心转子进行超声波检测 ,采用多种频率、多种波形及入射角、多种扫查方式对缺陷进行扫查、定位和定量 ,以研究各种扫查方式对缺陷的检出率、缺陷属性、缺陷位置的影响。在理论计算的基础上 ,补充进行了斜角探头中心检测盲区的分析和实物测试及斜楔对检测灵敏度的影响测试试验 ,总结出了我厂实心转子的超声波检测参数 ,包括对设备及器材的性能要求、灵敏度整定方式、补偿要求和扫查要求 ,并编制完成了我厂大型汽轮机用实心转子超声波检测工艺规程     

机械密封系统流场气穴特性数值分析

针对机械密封腔内流场在一定区域内会产生气穴的现象,建立密封腔的几何仿真模型。利用商业分析软件结合多相流模型对机械密封腔内流场的气穴现象进行数值模拟及优化,获得了机械密封腔内流场的气穴位置和分布情况。分析进口压力、转速对气穴产生的影响,并利用克里金(Kriging)插值方法对其组合进行优化。结果表明:在相同的初始条件下,不同冲洗液的进口压力和转速都对密封腔内气穴的产生具有促进或抑制作用;通过Kriging插值和误差分析,缩小了对气穴现象产生抑制的进口压力和转速组合的范围。     

圆锥环间隙中铁磁流体动密封的压差计算

推导了圆锥环密封间隙中铁磁流体运动的动力学模型,并在合适的假设条件下求得这一模型的解,得出了密封间隙中铁磁流体运动的压力分布.介绍了铁磁流体动密封的压差计算方法,从流体动力学方面阐述了提高压差的主要措施,并指出圆环密封间隙中因铁磁流体运动所造成的压差损失是不可忽视的.     

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。