机床再制造技术框架及产业化策略研究

机床再制造实际上是一种基于废旧机床资源循环利用的机床制造新模式,对于循环再利用我国量大面广的老、旧机床设备资源以及更新提升我国制造业机床整体质量和制造加工能力具有重要意义,并将导致若干新兴产业的形成.在分析国内外机床维改再利用现状及不足的基础上,总结提出机床综合再制造流程,并建立废旧机床再制造技术框架;结合机床再制造新兴产业的发展前景,分析并提出其产业需求、产业主体、产业模式等产业策略.     

机床再制造与综合提升内涵及技术框架

机床再制造是国家《循环经济促进法》及国务院多项文件中明确的重点领域。机床再制造属于典型的产品型再制造模式,是一种以废旧机床及零部件为坯料,以资源循环再利用为基础,通过对产品进行创新再设计、零部件再制造和整机系统集成,从而满足市场需求的机床制造新模式。阐述了机床再制造的定义、内涵及其与零部件再制造、机床维修改造等概念的区别和联系,并提出了机床再制造与综合提升的运作流程和技术框架;结合再制造实践,通过案例分析总结了机床再制造与综合提升的经济及社会效益。     

机床再制造实践

机床再制造是基于废旧资源再利用的新型机床再制造模式,符合我国循环经济和低碳经济的发展要求,对于提升我国量大面广、技术水平低的废旧机床的性能和信息化水平具有重要的意义。以C6132A1机床的再制造为例,对其再制造实践过程进行了详细介绍,包括再制造流程、再制造方案及再制造前后对比分析,为其他机床厂实施再制造提供参考。     

废旧机床再制造设计与研究

针对现代工业进程中的再制造工程技术阐述了废旧机床再制造的内涵及体系.在分析机床生命周期的基础上提出了废旧机床进行再制造的流程,以及判断废旧机床能否进行再制造的指标和方法,研究了废旧机床不同零件进行再制造的手段,能够达到资源充分利用、节约能源、减少污染的目的,为废旧机床的再制造研究提供了理论基础.     

老旧机床数控化再制造技术研究与应用

大量老旧机床的报废将造成严重的资源浪费和环境污染。采用再制造技术可将废旧机床改造为新的数控机床。再制造的主要内容包括采用表面技术修复机床的磨损、划伤表面，恢复并提高机床的机械精度；采用滚珠丝杠、步进电机直接驱动提高机床的运动精度；采用数控系统替代原机床的电气系统，提高其控制精度。机床再制造最大限度地利用了原机床零部件的剩余价值，提升了机床性能，为老旧机床的升级换代找到了新途径。使再制造技术成为建立节约型社会的重要技术手段。本文介绍了老旧机床再制造的过程和表面工程技术在机床再制造中的应用。     

聚焦再制造在中国的发展潜力及前景展望

<正>再制造是节能、节材、保护环境的必然选择,也是实现资源循环利用转变发展模式的战略需求。作为一项朝阳产业,中国再制造产业现状如何所谓再制造,是指专业化、批量化、规模化修复的生产过程,以废旧工业产品为对象,以先进技术和产业化生产为手段,使再制造产品达到或超过同类产品新品质量标准的产业。与新品相比,再制造产品可节省成本50%、节能60%、节材70%、减少排放80%。再制造产业是节约能源资源的有效途径、循环经济发展的高级形式,也是工业由粗放线性向循环集约推进的重要支点。     

老旧机床数控化再制造技术研究与应用

大量老旧机床的报废将造成严重的资源浪费和环境污染.采用再制造技术可将废旧机床改造为新的数控机床.再制造的主要内容包括采用表面技术修复机床的磨损、划伤表面,恢复并提高机床的机械精度;采用滚珠丝杠、步进电机直接驱动提高机床的运动精度;采用数控系统替代原机床的电气系统,提高其控制精度.机床再制造最大限度地利用了原机床零部件的剩余价值,提升了机床性能,为老旧机床的升级换代找到了新途径.使再制造技术成为建立节约型社会的重要技术手段.本文介绍了老旧机床再制造的过程和表面工程技术在机床再制造中的应用.     

GCMT2500大型复合数控机床再制造技术应用

目前国内废旧机床的数量庞大,再制造技术能到达对资源的充分利用、节约能源减少污染的目的,机床的再制造技术会是未来技术发展的必经之路。本论文以GCMT2500大型复合数控机床为例,首先对其再制造实践过程进行了详细介绍,包括再制造方案,拆卸方案和清洗方案的设计;然后对介绍了再制造流程的具体实施;最后对再制造机床的精度进行检验,为废旧机床的再制造提供了理论和实践的基础。     

再制造产业还需迈过几道坎？

近年来,随着我国经济的快速发展,资源短缺、能源紧张和环境污染之间的矛盾日益突出。再制造作为资源再利用的重要手段,发展前景广阔。在我国建设资源节约型和环境友好型社会大背景下,大力发展废旧机电装备再制造技术潜力巨大。     

我国再制造工程及其产业发展

再制造是维修工程和表面工程发展的高级阶段,是先进制造的重要组成,是废旧产品高技术修复、改造的产业化。近年来,中国的再制造发展迅速,已在再制造的政策法规、产业实践及基础研究方面成绩斐然。本文阐述了中国自主创新再制造的模式及内涵,综述了我国再制造质量控制关键技术,分析了国内再制造工程产业发展的前沿问题。     

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).     

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.     

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.     

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。