翻边装置在尾门总成夹具中的应用与研究

首先介绍了翻边装置在某汽车尾门总成夹具上的应用,通过在尾门总成夹具上增设带切换翻边装置,满足了尾门总成数模中无法通过包边模一次性包边区域的压合要求,通过夹具上的夹紧定位销对尾门总成进行孔定位,再通过夹钳部位的型面夹紧装置对型面进行夹紧及定位,确保翻边精度与外观质量要求。重点讲述了带切换翻边装置的夹具结构及工作原理,通过气缸、导杆、旋转轴、翻边刀块等的结构设计,实现了该特殊包边需求。实际生产证明,该翻边装置能有效地应用在尾门总成夹具上,满足了生产中对压合区域的翻边精度与外观质量要求,降低了车型工装的开发成本,并且实现了翻边压合,提高了生产效率。     

气动冲孔模设计

重卡车身的大型覆盖件,因功能增加或设计改型,往往会出现一些需要开孔的情况.因大型覆盖件重新开发模具的费用高,所以寻找在焊接夹具体上开孔的方法成为一种简单可行的途径.本文基于侧围外板需要开孔的实例,把气动冲孔模具安装在侧围总成夹具体上,通过简单的气动控制,达到冲孔目的.     

精密阀芯径向孔钻床夹具设计

针对某精密阀芯外圆表面径向孔尺寸和位置精度高、加工质量不稳定的情况,设计一种采用V形槽反装定位、偏心轮装置快速夹紧的专用钻床夹具。详细分析了径向孔加工钻床夹具的定位和夹紧方案,计算出定位元件关键尺寸,阐述夹紧装置的原理和工作过程。经夹具精度分析与验算,发现所设计的夹具完全能满足精密阀芯径向钻孔的高精度要求。该夹具操作简便、适应性强、工件加工质量稳定,为机械行业销轴类零件高精度径向孔钻床夹具的设计提供了参考。     

大型搪瓷水箱板块冲孔装置的设计制造

对悬挂式冲孔装置提出了采用限位块的安全措施 ,给出了夹具主体的机械加工工艺路线及注意事项 ,介绍了水箱板在悬挂式冲孔装置上的具体定位方法 ,通过更换附件 ,在1套悬挂式冲孔装置上完成多种规格、不同板厚、不同孔位的水箱板块的冲孔工序 ,极大地提高了生产效率     

焊胎中对带孔立板定位夹紧的新装置

组焊夹具中经常遇到带孔立板的定位夹紧问题 ,例如 ,收割机中过桥体和输送槽体中就有多个带孔立板的焊接需要定位夹紧。本文就是作者设计的一种适用于多种收割机用相同工装焊接的新定位夹紧装置。1　新装置的结构及工作原理(1)新装置的结构如图 1所示。其中拉杆、开口垫圈均为夹紧元件 ,导向套、导向销均为导向元件 ,滑套为定位元件 ,座板为支撑元件。(2 )新装置的工作原理　图 1中的双点划线为需定位的带孔立板。定位时沿导向套和导向销把滑套推到底并顺着滑套的导向槽旋转滑套到图示位置 ,此时滑套上外圆Ｂ和台阶Ｃ面为两定位面 ,把立板的…     

差速器壳体镗孔夹具设计

镗床夹具是镗孔加工中常用的辅助装置。针对差速器壳体上两组相互垂直孔的加工,设计了专用的镗孔夹具。鉴于差速器壳体的结构特点和镗孔工序要求,采用一面两孔定位,并确定了满足定位精度要求的定位销尺寸。接着,确定了可靠的工件夹紧方案,并设计了油缸以及相关的夹紧装置。最后介绍了该夹具的结构组成及其特点。     

汽轮机静叶片装配内背弧型面线切割工艺研究

汽轮机静叶片装配内背弧型面加工是汽轮机静叶片关键工序之一.针对汽轮机静叶片结构特征,应用线切割加工技术和工件定位原理,研究汽轮机静叶片加工工艺过程、装配内背弧型面线切割工艺、线切割夹具结构及夹紧工作原理、线切割工艺参数的调整方法,从而在满足加工零件的精度及表面粗糙要求的同时,在生产应用中形成了更加完善的工艺方法.     

带双压料机构的侧围外板侧整形模具设计

侧围外板是汽车的核心外覆盖件,其特点是形状复杂、工序内容繁多且零件的表面质量和尺寸精度要求较高.通过侧围外板的冲压工艺方案分析,提出一种带双压料的侧整形工艺和结构,可以有效解决整形起皱和回弹,同时达到保证A面质量的目的.重点介绍了侧围整形模结构、双压料侧整形机构的设计要点及工作原理,完成了侧围外板紧凑合理的侧整形模具结构设计.实际生产表明,该侧整形模具可有效解决整形起皱、回弹难题,提高零件成形质量,提升A面品质,缩短调试周期,降低工装开发成本.     

整体式汽车转向节夹具结构设计

基于汽车转向节结构复杂、加工精度要求高、定位困难、生产批量大等特点,对整体式汽车转向节加工工艺问题进行了研究针对加工过程中某一工序设计了一套翻转式铣面钻孔夹具,并运用三维图形软件Pro/E对所设计夹具结构进行建模和虚拟装配检验夹具空间布置和零件尺寸干涉性问题并修改同时对夹具的夹紧力和定位误差进行分析计算以确保该夹具可以满足汽车转向节大批量、高效、高精度的加工要求,提高了该转向节的生产效率和加工精度.     

基于短工序化的侧围外板冲压工艺与模具设计

为了减少侧围外板冲压模具工序数量,降低新车型冲压模具投资,以某SUV车型侧围外板为例,通过对产品成形性和模具结构可实现性进行分析,设计了满足短工序化的冲压工艺方案。引入多种复合模具结构和特殊斜楔,实现了侧修边与侧冲孔、侧翻边与侧冲孔、侧整形与侧翻边等不同工艺内容的同序化,从而将侧围外板冲压模具工序数量由4道工序缩短至3道工序,并完成工业化应用。实践证明,短工序化工艺方案可有效削减模具工序数量,提高生产效率,降低模具开发及后期生产成本,满足侧围外板的批量生产需求,对于汽车行业冲压模具的工序优化具有一定借鉴意义。     

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).     

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.     

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.