深孔钻断排屑机理与变切深加工数控宏程序研究

深孔加工面临许多困难,其中最主要的困难是断排屑、钻偏及折断钻头.文章针对深孔加工的特殊性,研究了切屑形成机理及各种断、排屑方式,采用“变切深、引钻”等方法并通过数控宏程序控制深孔加工,解决了断排屑、钻偏及折断钻头等难题,应用结果表明,深孔加工的断排屑效果明显,加工效率及精度显著提高.     

多层钎焊小孔钻高效排屑换热技术的研究

使用镍基合金焊料和高温真空钎焊技术,制作了Ф6 mm的金刚石薄壁钻头,进行了钻削对比试验。通过优化钻头基体外壁结构和在钻头内孔填充有机换热材料(石蜡)的方法,实现了无冷却液条件下钻削超硬工程陶瓷的高效排屑及换热。试验结果表明:侧面出现细长凹槽的钻头,能使钻屑及时高效的排除,钻头内部的固体石蜡可以阻止钻屑进入内孔,进一步增强侧面凹槽的排屑作用,同时石蜡的液化会带走大量的钻削热,起到瞬间高效的换热作用,能显著提高钻头的使用寿命。     

KC-TZ118型链轨节数控钻镗组合机床的研制

KC-TZ118型链轨节数控钻镗组合机床,是校企合作共同研发的高效率、高精度、高性能自动钻镗组合机床,专门用于挖掘机左右链轨节镗孔、钻孔的加工.主要介绍KC-TZ118型链轨节数控钻镗组合机床的方案确定、机床结构特点、机床参数的配置、数控系统的配置及调试方法等,并详细分析机床设计中的关键技术.     

硬质合金微型钻数控沟磨机夹料装置的改造

数控沟磨机是我厂从日本东芝公司引进的硬质合金微型钻生产线中用于磨削钻头排屑槽的设备 ,随着使用时间的不断延续 ,原系统设计的夹料装置在生产过程中的不稳定性逐渐暴露出来 ,严重影响了生产的稳定及产品质量的提高 ,为提高夹料装置在生产过程中的稳定性 ,达到提高产品质量的目的 ,从而对原夹料装置实施改造 ,收到了良好的效果     

基于切割工艺的钢板下料最优套料算法及实现

针对数控切割下料行业中任意形状零件套排的优化问题,依据离散数学的扫描线算法,在套排过程中融入了数控切割下料的特殊工艺技术,并根据局部最优的原则不断地将零件进行动态套排,直至套排结束。实际计算结果表明,该算法实用性强、速度快、效率高,获得了满意的套排结果。     

贯流风叶自动数控钻削去重动平衡系统研究与实现

针对贯流风叶手动粘贴平衡片精度低、效率低、易脱落等缺点,首次引入数控去重动平衡技术,自主研发贯流自动数控钻削去重动平衡系统。首先简述贯流风叶动平衡力学原理和二面平衡原理;其次对贯流风叶不平衡量钻削实现精确建模;同时,采用4个压电传感器作为硬支撑平衡机的不平衡量测量装置,输出第一和第二校正面X和Y方向的模拟量电压(0~10 V),经过信号处理电路后,再由PCL-812PG多功能数据采集卡传送给单片机控制系统;再者,通过补偿系统、电压与不平衡量的比例系数,计算得到两个校正面的不平衡量;最后精确控制两个进给主轴钻削,实现贯流风叶自动数控钻削去重动平衡。实验结果表明:研究设计的贯流风叶自动数控钻削去重动平衡系统的不平衡量减少率达到90%。     

动态规划粒子群算法解PCB数控钻孔最佳走刀路线问题

设计印刷电路板（PCB）数控钻的走刀路线是数控钻编程的重要组成部分,目前自动编程系统生成的钻孔路线未必是最佳走刀路线。本文在粒子群算法的基础上提出动态规划粒子群算法,并用此方法求解PCB的最佳走刀路线,获得了满意的结果。     

数控冲剪复合机在钣金冲裁领域的加工应用

数控冲剪复合机是一种高效的钣金加工设备,是集计算机控制技术、微电子技术、远程监控技术和精密制造技术于一身的机电一体化设备。该设备配合辅助的上下料系统,极大降低了生产人员的劳动强度,提高了工作效率,降低了劳动生产成本。本文主要对数控冲剪复合机在钣金加工领域的应用进行阐述,并对其在实际加工过程中的排样规范进行研究。     

裂解连杆长油孔加工关键技术的研究

针对1.5T汽油发动机的主要零部件连杆组件尝试用3种加工方法解决长油孔加工的技术难题。通过对3种加工方法加工效果的对比,最后选取了加工产品质量稳定、效率高、成本最少的数控深孔钻加工连杆的长油孔,就加工过程中所遇到的散热、排屑、导向装置、刚性差和枪钻的使用寿命等关键技术问题进行深入的分析和研究,并提出了有效的解决方法。     

典型零件在数控加工中心上的加工

分析喷油器体的结构特点,探讨加工该零件时的装夹方式,并阐述采用数控钻铣加工中心加工喷油器体端面各孔的工艺路线和刀具的选用,并优化钻铣加工工序。     

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。