四工位连续模的自动冲压

<正> 我厂导电片零件(图一)材料QSn6.5-0.1y0.5(YB461-71)。零件几何形状较复杂,以前用三道工序冲压:复合模冲孔、落料、压弯、成形。需三副模具,工人劳动强度大,生产效率低,安全可靠性差。 为了挖掘生产潜力,提高经济效益,结合我厂现有J—21型开式自动压力机设计,制造了《导电片》四工位连续模,进行冲孔、落料、压弯、成形。用一副模具代替三副模具在桂林第三机床厂生产的J—21型压力机上连续自动冲压,经过大批量生产表明:机床模具工作稳定,零件质量可靠,提高工效24倍。现将工艺排样、模具动作原理、模具结构分别介绍如下: 图2为工艺排样示图:冲孔,落料为双排样,先单边冲裁,待一卷料冲完后再调边     

密封盖冲孔-翻边-落料级进模设计

文中对密封盖零件的冲压工艺进行了分析,改用冲孔—翻边—落料连续冲压工步级进模生产,可明显提高制件质量及生产率,从而降低生产成本。介绍了密封盖毛坯的排样图、翻边工序、冲压力及压力中心等工艺计算,设计了密封盖冲孔—翻边—落料级进模的模具结构。     

顶罩冲压工艺分析及复合模具设计

根据顶罩零件的结构特点及生产类型,确定采用冲压加工方法。通过对顶罩零件加工工艺分析,提出了采用复合模具生产该零件。对该复合模具的主要零部件包括冲孔凸模、落料凹模、拉深凸模和凸凹模进行了设计,完成了该复合模具的组装。结果能为同类零件的冲压复合模具设计提供一些参考。     

一付多工序复合模

<正> 图1所示零件,材料:紫铜。按常规的冲制方法,每种零件至少需要两套模具(冲孔落料模+翻边模或者落料拉深模+冲底模),并应分别下料。我们根据零件的形状特点和使用情况,在不影响其使用性能的前提下,对零件原设计尺寸作了一些修改,设计制造了一付多工序复合模,将大件的落料、拉深、冲底、小件拉深、冲底五道工序复合在一起,使一次冲压能同时得到两种零件各一个。     

后备箱门锁保持架冲压工艺分析及级进模设计

通过对某款汽车后备箱门锁保持架零件的板料成形过程进行模拟,结合对零件工艺内容的分析,确定采用一种中间载体的双排级进模具来实现其生产,材料利用率为45. 6%。该级进模具共11个工位,成形内容包括冲裁、拉深、弯曲、冲孔、落料等。为保证零件的尺寸精度,在工序安排时先完成零件上拉深、弯曲工艺内容,再完成中间开口部分的冲裁工艺。在确保料带的输送稳定和级进模动作连续方面,模具采用弹性卸料板卸料、承料块托料的结构,并在冲压的中间过程增设辅助定位孔设计,利用导正销钉进行定位。在实际生产使用过程中,模具使用性能稳定,所得零件产品达到设计精度,同时也满足批量生产的要求。     

铜合金钥匙级进模设计

对铜合金钥匙的冲压工艺进行了分析,采用冲孔——落料连续冲压工步级进模进行生产,可明显地提高制件质量及生产率,从而降低生产成本。介绍了铜合金钥匙制件的排样图,冲压力及模具压力中心的工艺计算。设计了铜合金钥匙冲孔——落料级进模的模具结构。     

旋盖式油杯底座连续拉深模设计

通过对旋盖式油杯底座的成形工艺进行分析和计算其毛坯尺寸,提出了落料、拉深及冲孔等冲压工艺,为满足生产批量的需求,确定采用1模2件排列的连续拉深模的排样方案,并介绍了旋盖式油杯底座的整体模具结构和主要零部件设计,对拉深工艺计算、模具的部分结构设计、部分拉深及整形凸、凹模的加工工艺进行了详细阐述。经实际生产验证,该零件的排样方案及模具结构合理可行,生产的零件质量合格,生产效率高,为同类零件的连续拉深设计提供了一定的参考价值。     

汽车过滤器后支架级进模设计

汽车过滤器后支架零件的形状和结构包含冲切、翻边、压印、弯曲和分离等冲压工艺特征。分析其零件结构、生产批量和冲压工艺性,采用级进模可满足零件生产要求。为保证制件的精度和连续冲压过程,设计了与分离工位角度相同的工艺切口,并在对应工位的模具设计了让位槽,确定了以冲孔、冲切、弯曲和整形为主的排样方案;采用导尺配合导正钉定位,设计了内外导向机构和弹性卸料装置进行压料和卸料以保证产品精度;对设计的模具进行了加工、试冲。结果表明,设计的10工位级进模结构合理,成形的产品符合尺寸和精度要求。     

汽车后安全带固定座冲压模拟及模具设计

分析计算了汽车后安全带固定座的冲压工艺,确定了落料冲孔翻边复合模冲压方案。利用DYNAFORM软件得到了制件翻边前的落料形状并模拟了制件翻边成形过程,验证了落料冲孔翻边复合模冲压加工的可行性。设计了1副落料冲孔翻边复合模,并阐述了模具结构、工作过程及设计制造要点。生产实践表明,该模具能够一次完成落料、冲孔、翻边工序,操作方便可靠,保证了制件的形状和精度。     

铁路货车底门板冲孔落料模设计

阐述了尺寸较大冲压件落料冲孔的设计理念。设计了1副复合模完成冲孔和落料,保证模具生产的工件具有互换性,保证模具设计基准与零件设计基准和制造组装基准的统一和匹配,实现批量生产的需求;降低模具的冲裁力,实现安全生产;设计模具的柔性结构,能快速更换模具的备件;探讨模具的新结构,提升了模具的安全性。     

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。