圆形凸台件的冷挤压工艺及模具设计

对圆形凸台件的冷挤压工艺与机械加工工艺进行了比较，对圆形凸台件进行了冷挤压工艺分析，叙述了工艺难点，详细叙述了圆形凸台件冷挤压工艺的工序设计、毛坯计算、毛坯软化处理、凸、凹模的设计及模具整体设计、介绍了圆形凸台件的冷挤压工艺的优越性。     

汽车半轴锻造模具热处理工艺分析及改进

首先对常用的汽车半轴锻模的各项热处理工艺进行分析和概述,详细绘制了各项工艺曲线图;其次,通过实验方法对原有的淬火工艺、回火工艺以及表面强化工艺进行改进,绘制了改进后的热工艺曲线图.通过实验方法验证了改进后的工艺的可行性.结果表明,对3Cr2W8V汽车半轴锻造模具加工工艺的改进,提高了模具的高温强度、冲击韧度、耐磨性能、表面硬度以及模具使用寿命.     

消失模铸造工艺技术研究及应用

根据消失模铸造工艺特点,对装载机变速箱体、壳体等的铸造工艺进行了深入的研究,依据国内、外相关设备、材料和工艺情况,对工艺方案、设备选型等进行论证,优化了工艺过程,铸造出高精度产品,实现了高质量工程机械铸件的集约化、规模化生产,取得了重要成果。     

计算机模拟在冷却机轮毂铸造工艺设计上的应用

运用传统的铸造工艺设计方法对轮毂铸钢件铸造工艺进行了初步设计;利用V-Cast模拟软件,对轮毂初始工艺的凝固过程进行了模拟,分析了初始工艺产生缺陷的部位和原因.在此基础上通过添加、调整冷铁,进行工艺优化,最终获得了合适的工艺方案.模拟结果显示,优化工艺实现了轮毂的顺序凝固,消除了缩孔、缩松缺陷.     

面向智能决策的结构化工艺知识建模建库技术研究

为了解决智能制造工程中的工艺知识处理与决策技术问题,通过对工艺分析、工艺方案、等工艺业务过程的知识应用需求分析,重点研究工艺知识的表示、获取、处理、共享和决策等技术,并建立了工艺知识体系和可定制的结构化工艺知识模型,为知识驱动的工艺智能决策和快速工艺设计提供了坚实的基础和保障,对航空企业工艺知识库的建设具有一定的参考和指导意义。     

汽车缸体铸件铸造工艺研究

缸体是汽车发动机的核心部件,针对汽车缸体成形和结构工艺上的缺陷,结合缸体的技术要求,对缸体的成形工艺进行设计,确定了缸体的制芯方案、分型面、浇注系统、加工余量等成形工艺方案。通过缸体辅助工艺分析,最终确定了制芯工艺参数、组芯工艺、涂料及烘芯工艺、浇注工艺、造型工艺、熔炼工艺、清理及检测工艺,为汽车缸体的研究和开发提供了技术支持。     

壳型铸造轿车凸轮轴材料和工艺的研究

介绍了采用壳型铸造工艺生产轿车凸轮轴的流程、制壳工艺、铸型工艺及铸件布置、铸型装箱及铁丸充填工艺,以及浇口杯、冒口和过滤网的选择方法;对低合金灰铸铁凸轮轴熔炼和浇注工艺进行了研究,根据研究结果找到了较合理的成分调整方法、配料与加料原则和熔炼、孕育处理、浇注要点.探讨了化学成分、孕育方法、熔化和浇注工艺对氩弧重熔淬火凸轮轴质量的影响.     

圆锥破碎机传动轴架的铸造工艺设计及模拟优化

运用传统的铸造工艺设计方法对圆锥破碎机传动轴架铸造工艺进行了初步设计,利用V-Cast模拟软件,对传动轴架初始工艺的充型和凝固过程进行了数值模拟,分析了初始工艺产生缺陷的部位和原因。在此基础上,通过添加冷铁,优化了铸造工艺,对优化工艺再次进行了模拟。模拟结果显示,优化工艺实现了传动轴架的顺序凝固,消除了缩孔、缩松等缺陷。生产实践表明,采用优化工艺生产的传动轴架内部组织致密,符合技术要求。     

快速凝固过程中熔液自旋工艺的比较

对自由喷射熔液自旋工艺、旋铸法、平面流锛、熔体提淬工艺、熔体拖拽工艺、双辊法等冰种快速凝固技术熔液自旋工艺进行了综述，着重从工艺原理、工艺特点等方面对它们进行了比较 。     

树脂砂制芯工艺在东风汽车公司的应用

本文介绍了东风汽车公司铸造厂使用树脂粘结剂,采用壳芯法、热芯盒法、冷芯盒法工艺生产汽车铸件的基本工艺,并对上述工艺进行了对比评述,对生产中常见缺陷提出了改进措施,还为今后制芯工艺的发展提出了一些设想。     

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。