基于UG和VERICUT的航空薄壁件数控加工与仿真研究

针对某航空薄壁件的结构特点和加工难点进行分析,合理设计装夹方式,并进行工艺编制。基于UG软件进行零件的数控加工编程,生成刀具轨迹及NC程序,通过VERICUT仿真平台对该航空薄壁件进行仿真加工,检验数控程序的正确性,并对数控加工参数进行优化,避免实际加工中机床与零件发生碰撞或干涉等情况。实践结果表明该方法提高了加工效率。     

基于MasterCAM的深槽窄缝零件数控加工技术研究

分析深槽窄缝零件的结构特点,介绍应用M asterCAM X2软件对深槽窄缝零件的数控编程、仿真和加工工艺的规划,并分析了数控编程中加工策略的选择及参数的设置,解决了数控编程中选用小直径刀具的加工工艺难点,取得了良好的加工效果。     

基于UG12.0的注射模型芯数控铣削编程

注射模零件进行数控加工编程前，应对零件结构进行分析，根据模具结构对零件实体的要求进行适当修改，删除实体上的推杆孔、斜推孔、流道等特征，再分别对模具零件的胶位面、分型面、配合面等进行数控铣削编程，编写的数控刀路经仿真验证，可以加工符合要求的模具零件。     

基于特征加工技术在自动数控编程中的应用

应用MasterCam软件的FBM Mill和FBM Drill两类基于特征加工功能,实现实体零件的自动数控编程.首先.在Solidworks软件中完成实体零件的特征建模,将模型导入至MasterCam软件;然后,设置零件的毛坯尺寸及FBM参数,在指定的机床上自动生成所有特征零件加工部分的二维刀具路径:最后利用数控加工仿真验证了自动生成的基于特征的NC刀具轨迹.采用基于特征加工技术消除了实体零件铣削和钻削编程操作中所涉及的特征识别的手动工艺流程,大大提高了编程效率与编程灵活性,是实现自动数控编程的一种有效方法和手段.     

基于UG的大力神杯4轴数控加工技术

分析大力神杯模型的结构特点,介绍应用UG软件的4轴加工技术对大力神杯模型零件的数控编程、仿真和加工工艺的规划,并分析了数控编程中加工策略的选择及参数的设置,解决了数控编程中倒扣图形的加工工艺难点,取得了良好的加工效果。     

塑料模零件淬火过程有限元模拟分析

采用有限元分析软件ANSYS Workbench对塑料模零件淬火过程中不同时段的温度场、应力场及变形情况进行了数值模拟,有效预测了塑料模零件的变形和开裂部位,通过模拟数值对塑料模零件淬火方式及工艺参数进行了优化。     

基于NX 10.0的安装面板型芯的编程设计与机床仿真加工

在分析了安装面板型芯结构特点及加工工艺的基础上,对零件进行了数控加工工艺设计,并结合NX 10.0对工件进行了编程设计与机床仿真加工。本文详细介绍了模具型芯零件的编程方法,对工件进行机床仿真加工设计,通过实时观察机床和刀具的运动轨迹,预防刀具干涉或撞刀情况的发生,减少工件的试切加工次数,降低了生产成本。     

薄壁零件铣削加工物理仿真平台的开发

薄壁零件具有质量轻、结构紧凑、比强度高等优点,在航空航天、精密仪器等行业应用广泛。研究零件切削过程中切削力作用下的变形情况具有重要意义。根据薄壁零件的加工变形仿真分析流程,使用有限元分析和混合编程相结合的方法,基于C#、APDL、MATLAB语言开发了可移植的只需在界面上进行简单操作就能完成零件加工的数值分析和结果后处理的仿真系统,并进行了验证分析。     

一种深小孔加工工艺的研究

针对一副注射模动模镶件顶针孔的结构特点，首先对其进行工艺分析，然后从工件装夹、刀具选择、切削用量选择及数控编程与加工等方面优化工艺方案，利用普通麻花钻和铰刀对其进行加工，最终达到了零件的技术要求。丈中结论为深孔切削加工提供了有价值的参考。     

基于图的特征识别方法在注塑模加工中的应用

对塑料模模架的零件特征进行了分类，采用基于图的方法表达特征，用基于图的特征识别方法来识别模架零件中的主要特征，并将其按加工要求输出，生成NC程序应用于生产中，提高了注塑模模架零件的设计和制造的效率和质量，对注塑模模具的生产具有重要意义。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.