梅花形孔光洁冲模

<正> 加工图一所示的梅花形孔,用常规机械加工方法,工效低,尺寸精度及光洁度都不 易保证。而采用普通冲模进行冲裁,尽管工效较高,但不能达到零件的加工要求。为此,我们设计了一付结构如图二的光洁冲孔模。用工件外形定位,一次冲裁成功。尺寸精度     

汽车离合器减振盘冲压工艺优化及模具设计

对离合器从动盘总成零件中的减振盘进行冲压工艺分析,将原工艺的4道工序减少为3道工序,并阐述了减振盘冲压工艺特点及模具设计要点。通过对减振盘冲裁工艺的优化设计,解决了零件位置精度差的问题,在翻边模设计中对不同尺寸要求的位置设计不同成形间隙,以满足零件尺寸要求,成形模上、下成形板型面设计为斜面,以补偿成形过程的回弹。经生产验证,优化后成形的减振盘零件尺寸和位置度均满足要求,提高了生产效率,降低了生产成本。     

某汽车底梁加固件多工位级进模设计

为了提高汽车安全性及减轻车身重量,高强钢板结构件在汽车制造上的应用越来越广泛。某汽车底梁加固件的材料为高强钢GMW3032M-ST-S-CR340LA,其结构复杂、精度要求较高。针对该零件的结构特征进行了冲压成形工艺分析,确定了采用中间载体、双排排样的12工位级进模冲压工艺方案,并对级进模的总体结构和关键结构进行了设计。部分冲裁凸模采用单峰斜刃结构,能有效降低冲裁力;采用压弯拉深复合成形模具结构,可以减小级进模的工位数;设计了吊装式斜楔机构,能够简化加工工序、方便工件的取放。试冲结果表明,使用该套模具生产的制件满足尺寸精度要求,生产效率高。     

套裁垫片聚氨酯橡胶冲模设计

分析比较了用套裁两种带孔垫片聚氨酯橡胶冲模代替单只垫片冲孔、落料单工序模具,可减少冲压工序,提高生产率及降低产品成本。介绍了套裁两种带孔垫片聚氨酯橡胶冲模的模具结构及主要零件的加工技术要求,计算了冲裁力及内、外凸模工作部分尺寸。     

新型全自动板料冲裁模结构设计

为改变现有板料冲裁模生产中存在的自动化程度较低的人工送料和取件方式,对板料冲裁模结构设计进行了研究。从工艺方案的确定、模具结构尺寸计算和冲裁力计算等方面阐述了冲裁模设计的流程,设计了新型冲裁模具的自动送料和自动取件装置;并利用3D软件的运动仿真功能对板料冲裁过程进行了模拟。结果表明,设计出的新型自动冲裁模,可以实现冲裁过程中的送料、定位、成形和取件等工序的全自动化生产,极大地提高冲压加工的生产效率,实现冲压加工的完全自动化。     

锁扣成形模设计与加工

锁扣零件示意图如图 1所示 ,材料为厚 0 .6ｍｍ不锈钢板 1Ｃｒ13,由板料冲压成形。由于零件较小 ,要求较高 ,采用复合冲裁模落料 ,弯曲成形模一次成形以保证精度。图 1　锁扣零件示意图模具设计、加工前需进行必要的计算 ,如冲裁力、展开长度、线切割加工编程前刃口尺寸的计算等。由于零件较小 ,板料厚度只有 0 .6ｍｍ ,需要的冲裁力很小 ,冲裁力就不计算了 ,模具的强度也不校核了。复合模的关键件是凸凹模 ,最小壁厚只有 1.1ｍｍ ,极易损坏 ,落料和冲孔的废料一定要流畅排出 ,防止堵塞 ,确保其使用寿命。在结构上可将凸凹模内孔割成锥度以…     

叶片孔分度冲孔加工的数控化

叶片孔分度冲孔加工的数控化２５５０１２淄博市山东工程学院赵庆志，杨慕升１问题的提出图１ａ所示的叶轮盘是空调机上的重要零件。叶轮盘厚度δ＝０．５～２ｍｍ，其周边均布若干叶片孔。叶片孔所在圆的最大直径为５００ｍｍ，设计上要求叶片孔距累积误差小于０．２ｍｍ...     

提高冲裁模寿命,降低冲压成本

一、引言在板料冲压车间里,一副冲裁冲模压的零件是有限的。冲裁模冲压零件的数量是由工件所允许的毛刺高度决定的。冲头和凹模要根据其磨损程度进行修磨。一副冲裁模在刃磨前的冲裁零件数就是冲裁模的寿命。冲栽模寿命的差异很大,但可以采取各种措施加以提高。这一点,冲压车间的人们都知道,实验室研究也业已证明。最常用的办法是以硬质合金     

护盘冲孔落料工艺分析与模具设计

通过该护盘零件,分析了零件的冲制加工工艺及难点,提出了该零件冲裁模的设计方案,介绍了护盘零件冲裁模的设计方法及模具结构特点,得出了采用复合模进行阶梯冲裁相对合理的结论.经过生产运用零件满足产品质量要求.     

汽车离合器盘毂法兰盘成形工艺分析

根据汽车离合器盘毂的结构特点,设计其轴杆部分与法兰盘分开加工的工艺,探讨了厚度为3mm的离合器盘毂法兰盘采用精密冲裁的可能性。首先利用有限元方法,采用Deform-3D对法兰盘精密冲压进行模拟仿真,分析不同间隙以及不同压边力和反压力对工件质量的影响,结果表明:厚度为3mm的离合器盘毂法兰盘可采用精密冲裁加工;当模具间隙0.03mm,压边力为800kN和反压力为400kN时零件质量较好。     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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.