汽车B柱零件热冲压软区模具模面优化设计

B柱软区模具处于高温工况条件下,由于热膨胀作用模具模面会产生较大热变形,因此,需要进行模面优化补偿。建立了B柱软区模具传热有限元仿真模型,基于Isight软件并应用MMFD优化算法,以模面温度为优化目标,调整了3组加热棒功率,使模具模面温度达到生产标准。应用加热棒功率参数,建立了模具热应力有限元模型,模拟发现模具模面产生较大热膨胀变形。以B柱零件的膨胀量为基准,设计模具模面优化流程,经过两次模面补偿,模具模面达到精度要求。按照设计的模具模面制作模具并进行实验,结果表明,模具传热仿真结果准确,生产的零件达到精度要求。     

螺旋伞齿轮闭式精锻模设计

介绍了螺旋伞齿轮闭式精锻新型模具结构,该模具采用浮动凹模和浮动模芯结构,锻件在2个凹模和2个模芯形成的封闭模腔中成形,生产的锻件无飞边。工艺试验表明:新型模具可显著降低锻压变形力、材料消耗和生产成本,提高了模具寿命和生产效率。     

车架纵梁冲孔模装配调试

分析了车架纵梁冲孔模结构,提出了特大型模具装配调试的难点,在模具生产中没有调试模具用的大型冲压设备情况下,结合模具结构和生产设备的现状,提出了可行、较简便的调模工艺方法,解决了特大型冲孔模的装配调试难点。     

收录机顶壳注射模设计

分析了收录机顶壳塑件工艺特点,介绍了顶壳注射成型模结构及模具的工作过程.模具采用一模多腔排位的方式及独特的流道与进浇口的设计,另外对于倒扣位采取有效措施的保证出模,模具开模顺畅.经生产验证,该模具结构设计符合生产要求,操作方便,模具寿命长,塑件达到技术要求.     

圆管双头冲孔与翻孔模具设计

介绍了一种铝合金圆管双头冲孔与翻孔模具,描述了该模具的结构组成,介绍了凸模、凸凹模、凸凹模保护结构及限位结构等工作原理。实践表明,该模具可适用于生产不同管径和长度的圆管系列零件,模具结构简单紧凑,提高了生产效率,降低了模具制造成本。     

空调空气幕风叶轮片级进模设计

分析了空调空气幕风叶轮片的成形工艺特点,对排样方案和模具结构进行了设计,介绍了模具结构的主要特点及其工作原理,详细描述了模具主要零件的结构,包括凸模、凹模、卸料板和凸模固定板,并提出了保护小凸模的有效方法。实际生产表明,该排样方案和模具结构合理有效,延长了模具的使用寿命,为生产类似产品提供了参考。     

汽车发动机盖类制件共用开卷落料模设计与应用

传统的一个冲压件使用一副模具的生产方式,导致模具开发成本及周期增加,生产过程中生产不同的冲压件需要更换相应的模具致使生产效率低下。针对汽车发动机盖内、外板冲压件及开卷落料模结构相似的特点,研发了可实现多车型共用的开卷落料模,分析了该模具的工装设计要点,并将制造加工出的模具工装成功应用于某企业多个项目中。该结构有效地降低了模具开发成本及周期,连续生产无需更换模具,节省了换模时间,进一步提高生产效率。     

防滑钉粉末冶金模具设计

根据硬质合金防滑钉的结构特点,设计了防滑钉的粉末冶金压坯模具,对上凸模、下凸模及凹模都进行了详细说明,模具采用1模6腔的形式,提高了生产效率,对企业的生产,该模具的结构设计具有较强的工程指导意义和现实参考价值。     

套筒热挤压工艺与模具设计

给出了套筒零件实用的热挤压工艺和模具结构,论述了模具的工作过程及凹模与凸模设计。该模具通过更换凸、凹模,便可生产不同规格的反挤压杯形挤压件,提高了模具利用率,降低了生产成本。     

反射体零件模具设计

分析了反射体零件的形状、结构特点,采用以保力龙为材料的消失模铸造生产模具的模座、凸模、凹模等零件,合理使用氮气弹簧作模具的弹性元件,简化了模具对压床的使用要求,合理应用设备,提高了零件的生产效率,实现了零件成形、冲孔、切边模的设计与制造。     

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.