带切换机构的斜楔在汽车顶盖模具的应用与研究

介绍了一种带切换机构的开花斜楔在汽车顶盖翻边模具中的应用,通过对顶盖的冲压工艺及模具结构的分析,采用一种气动切换机构和开花式的斜楔机构,实现了有天窗和无天窗两种状态顶盖的翻边工艺在同一副模具上进行,阐述了顶盖翻边开花斜楔及切换机构的结构及工作原理,设计的结构具有降低模具工装开发成本、节省冲压车间占用面积和提高工作效率的特点,经过实物生产验证,生产的有天窗及无天窗顶盖的总精度均达到了94%,满足了轿车对外板件的精度要求。     

汽车顶盖天窗侧整形模设计

通过对汽车顶盖零件特点分析,介绍了顶盖的冲压工艺,设计了顶盖天窗侧整形模。根据生产需要,在第四工序的天窗翻边部位设计三组侧整形斜楔,侧整形凸模、凹模均要设在下模,模具可以成形出有天窗和无天窗的汽车顶盖这两种制件。重点介绍了顶盖天窗侧整形模中的两种双动斜楔结构的应用,在顶盖天窗左边位置采用两组对向的电车斜楔,布置在下模中部区域附近,由两个驱动块分开驱动,模具调整方便,结构稳定性好;在天窗前后侧位置采用复动斜楔,模具结构紧凑,节省了模具空间。通过本模具中对双动斜楔的灵活运用表明,模具结构稳定可靠,方便了制造与调试,节约了成本,保证了产品质量,提高了生产效率。     

全景天窗顶盖修整复合工艺与模具设计

以某汽车全景天窗顶盖为研究对象,通过对全景天窗顶盖产品的工艺性和模具结构布局的成立性进行分析,合理规划各工序的工艺内容,实现了全景天窗顶盖两侧流水槽修边与侧整形的工序集成、后侧尾翼安装面修边与侧整形的工序集成以及天窗开口部修边与翻边的工序集成,从而将全景天窗顶盖冲压模具工序从4工序缩短至3工序。重点阐述了实现全景天窗顶盖冲压模具3工序化所应用的两种凸模扩张斜楔机构。在全景天窗顶盖两侧流水槽设计了一种水平推拉式凸模扩张斜楔机构,在全景天窗顶盖后侧尾翼安装面设计了一种竖直推拉式凸模扩张斜楔机构。研究表明,两种不同类型的斜楔机构的联合应用,可以使全景天窗顶盖在同一工序完成更多的工艺内容,实现了三面负角结构的修边与侧整形的同步化,缩短了冲压模具工序,降低了冲压模具成本,提高了零件的生产效率。     

轿车顶盖模具天窗的冲翻方式

介绍了带下压料的天窗冲翻结构在轿车顶盖天窗中的应用.通过对顶盖的冲压工艺以及对顶盖模具的结构的分析,在无顶盖天窗模具后增加一副带下压料冲翻结构的模具,实现轿车顶盖有天窗和无天窗两种状态.与传统的顶盖生产模具相比,该结构不仅能够降低模具设计开发成本,也能够节省冲压车间的占用面积,还可以提高模具的生产效率;与带有切换机构的...     

某车型顶盖天窗与非天窗防错研究与应用

针对某车型顶盖天窗与非天窗切换无有效防错导致模具受损的问题,在剖析顶盖天窗与非天窗切换模具结构原理的基础上,借鉴零件成形到位检测的思路,分别在修边、正翻边、侧整形工序中的顶盖天窗整形驱动垫块两侧加装感应器,利用感应器检测的信号作为压力机下行的判定条件,并更改压力机整线控制PLC程序,实现压力机的启停或自动报警停线。生产试验表明,该改进方案可有效建立成形天窗与非天窗切换防错机制,规避人工确认不到位造成模具受损的风险,为汽车覆盖件冲模的设计提供参考。     

全景天窗顶盖侧整形模设计

以某车型全景天窗顶盖为例,通过对零件结构进行分析,介绍了全景天窗顶盖冲压工艺,设计了用于成形全景天窗口部特征的侧整形模,并阐述了2种双动斜楔机构在全景天窗顶盖侧整形模中的应用。实际应用表明,凹模扩张斜楔机构与凹模收缩斜楔机构的联合使用,使模具机构更加紧凑和稳定,实现了全景天窗口部沿周负角法兰的同步成形,减少了成形工序,降低了零件制造成本。     

汽车翼子板四序化冲压工艺方案及翻边整形模设计

通过对汽车翼子板产品成形性及模具结构可实现性的分析,合理排布各序冲压工艺内容,并采用旋转斜楔机构有效实现了翼子板四序化生产。介绍了一种可实现四序化生产的汽车翼子板冲压工艺方案及其翻边整形模设计,重点讲述了该工艺方案中各工序的工作内容、设计要点以及两种不同形式的旋转斜楔机构的结构及工作原理。旋转斜楔机构的应用可缩短模具长宽方向上的工作行程,减小了安装空间,有利于更多的工作机构在同一副模具内安装。实际生产证明,该冲压工艺方案可有效降低冲压工序数,减少模具工装开发成本及后期生产成本,提高生产效率。     

轿车侧围外板冲压成形工艺优化

通过分析轿车侧围外板结构特点及成形工艺过程,采用特殊的复合结构模具,通过修边与整形复合、直翻边整形与斜楔翻边复合及直翻边与斜楔冲孔复合,使轿车侧围外板冲压工序由5道减少至4道。经生产证明:优化后的冲压工艺可行,模具数量减少,缩短了模具生产周期,提高了生产效率,降低了制造成本,为类似冲压件的工艺设计提供了有益借鉴。     

翻边整形工艺对纵梁类制件精度的影响

介绍了冲压模具中翻边整形工艺对汽车车身纵梁类制件精度的影响,翻边整形工艺的结构设置及优化降低纵梁类制件反弹、扭曲缺陷从模具工艺上的解决方法,并从日常生产质量控制、工艺设计、冲压模具结构等方面,简述了合理的模具设计及翻边整形工艺结构、角度设置对改善汽车车身纵梁类制件反弹缺陷的重要性。     

顶盖整形工艺分析及模具设计

介绍了汽车上常见的外覆盖件冲压工艺方案的确定过程，并以”郑州尼桑“轻型皮卡”顶盖“为例，针对此件成形难，取件难这一难点，确定了是冲压工序为：拉延、修边、翻边、整形。且着重整形模具的设计要点及整形以后顺利取件等措施。     

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.     

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.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.