机床数控化再制造信息数据库研究

对老旧机床进行数控化再制造可以使旧机床恢复精度,并实现数控化,但其涉及技术繁多庞杂,文中介绍了老旧机床在数控化再制造过程中需要涉及的各种技术,并对这些技术归纳、分类研究分析,研发出信息数据库,为老旧机床数控化再制造提供强大的技术支持.     

机床数控化再制造信息数据库研究

对老旧机床进行数控化再制造可以使旧机床恢复精度，并实现数控化，但其涉及技术繁多庞杂，文中介绍了老旧机床在数控化再制造过程中需要涉及的各种技术，并对这些技术归纳、分类研究分析，研发出信息数据库，为老旧机床数控化再制造提供强大的技术支持。     

运用技术创新与技术改造相结合机床再制造数控化领域有待加速发展

正机床制造业是我国高端装备制造业的重要体现,随着机床产业对产品生产精密度及效率要求的提升,我国机床行业当前急需通过对数量庞大的普通机床再制造数控化改造相契合。数控机床改造的市场前景近几年,我国机床行业经济增长迅速,生产机床的数控化率有所提升。但是我国有各类普通     

机床数控化再制造

以计算机数字控制技术(CNC)和表面工程技术集成为手段的机床数控化再制造，能使老旧机床批量翻新并提升其性能。机床数控化再制造的成功应用，降低了资金投入，节省了资源消耗，减少了环境污染，提高了工作效率。研究表明：在保证加工精度的前提下，机床数控化再制造与购置新机床相比可节约经费60％～80％。     

机床数控化改造的主要模式和关键技术研究

机床数控化改造既符合国内机床工业现状,又适应现代制造技术迅猛发展的要求.重点探讨机床数控化的三种技术模式以及各自的市场前景,并详细介绍机床数控化的关键技术.     

机床数控化改造中电磁兼容性问题探讨

普通机床的数控化升级改造，对于我国中小企业意义重大，数控设备的电磁兼容性问题是机床数控化改造的成败关键因素之一。本文重点讨论了数控机床的常见的电磁干扰源、干扰耦合途径以及抗电磁干扰的措施。     

基于生命周期的机床绿色制造关键技术研究

针对在机床行业中正在系统全面实施的绿色制造技术,围绕机床产品生命周期进行了研究。探讨了从机床的绿色设计、绿色加工工艺、机床的再制造、机床的回收再处理以及机床的数控化和智能化等绿色制造的过程,以期对我国机床行业绿色制造的发展具有一定的促进作用。     

面向多寿命周期的全域再制造升级系统

再制造升级能够高效益提升产品的综合性能,实现产品的多寿命周期循环使用,具有重要的资源、经济和社会效益,是再制造工程的重要组成部分及发展方向。建立了面向产品设计、制造、使用、再制造等多寿命周期的再制造升级全域工作内容,提出了涵盖支撑技术外围层、评估技术过渡层、实现技术核心层的三层次多寿命全域再制造升级技术内容框架,并重点给出了核心层再制造升级实现技术的主要内容;关键的实现技术为基础,进一步拓展构建了基于理论基础、工程技术和应用工具的三模块再制造升级工程理论与技术系统,明确了再制造升级的理论、技术与应用3方面应包括的实施内容;以研究的体系成果为指导,建立了机床再制造升级系统工艺流程,并开展了机床数控化再制造升级验证,升级后的机床满足了数控化和精度要求。     

机床的数控化改造方法研究

从机床数控化改造的方案评估入手,阐述进行方案评估所包括的具体内容及其必要性,分析了数控系统的选择与开发方法,同时对机床数控化改造过程中机床的安装与维护及标准化管理进行了相关分析,指出了机床数控化改造是一项复杂的系统工程,在实施改造时必须兼顾系统升级的需要。     

XK5040机床数控化改造

机床数控化改造可大大提高设备的自动化能力和生产率水平,满足企业对生产设备更高的要求.文章介绍了XK5040机床数控化改造技术,包括机床数控化改造方案优化选择、进给传动系统,主传动系统,选择合适计算机数控系统、对机床     

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。