弹簧片精密级进模设计

分析了镀金弹簧片的成形工艺及各工位的成形状态,介绍了弹簧片的排样设计及弯曲成形的方式,并确定级进模的总体结构。经实践证明：模具结构稳定、可靠,能保证成形制件的质量,对此类制件的模具设计提供参考作用。     

汽车后侧板多工位级进模设计

分析了汽车后侧板的冲压工艺,确定了包含5个弯曲工步成形的排样方案;介绍了后侧板多工位级进模的整体结构和主要零部件设计;依次展示了5个弯曲工步的模具断面图,为保证条料的同步移动和送料顺畅,模具采用浮动顶料机构。确定了级进模模具设计方案,该模具充分利用工件本身的结构特点,采用自动卸料、出料和少废料冲裁,有效提高了材料利用率。试冲结果表明,提出的排样方案和设计的12工位级进模合理可行,使弯曲件的质量得到了保证,可以满足汽车后侧板零件的大批量生产需要。     

高速列车安装板多工位级进模设计

高速列车安装板外形尺寸为275.3 mm×112.5 mm×29.5 mm,其弯曲部分为不规则Z字形,Z字形结构由2个方孔、1个圆孔和1个腰形孔组成,中间设有1条补强筋。根据安装板结构较为复杂的特点,对其成形工艺进行分析,在此基础上制定了3种冲压方案,经过对比分析,最终确定采用9个工位级进模成形制件,并确定了制件压筋预成形整形的排样方案。依次介绍了安装板模具的整体结构设计、模具预成形结构设计和模具成形工序结构设计。冲压成形工艺试验表明,安装板多工位级进模结构设计合理,其中采用预成形工艺能很好地克服制件回弹问题,满足制件大批量生产的需要。     

某高强钢板汽车结构件多工位级进模设计

为达到轻量化目的,汽车上越来越多地使用高强钢板结构件。通过对某高强钢板汽车安装座件的冲压工艺性及冲压工艺方案的分析,确定了采用13工位级进模来进行制件成形的冲压工艺方案;通过对制件的单排和双排排样方案进行分析比较,选择了双排排样方案,并对级进模的主要零部件进行设计。试冲结果表明,提出的双排样方案和设计的13工位级进模是合理可行的,能满足某高强钢板汽车安装座件的大批量生产需要。     

航空座椅连接件多工位级进模设计北大核心CSCD

根据航空座椅连接件的形状、尺寸、材料以及生产要求,对其进行冲压工艺分析。设计了由4个冲裁工位、4个弯曲工位、2个翻边工位、1个压型工位、1个切断工位和2个空工位构成的排样方案。该排样采用单侧载体,步距为50 mm,材料利用率为45.1%,提出采用多工位级进模进行生产。由于该工件的结构中弯曲成形较多,回弹不易控制,对其材料的回弹角进行了仿真,在弯曲成形中考虑了回弹量并进行模具补偿。为了便于维修和拆卸,采用直通式异形凸模,采用悬挂式销钉固定;圆孔冲裁凸模采用阶梯台肩固定,凹模均采用镶块式结构;并采用定位销进行定位,保证了模具精度。经过试模生产,多工位级进模的结构设计合理,能够满足零件的精度要求。     

连接器端盖高速精密多工位级进模设计

分析了连接器端盖的结构工艺性及冲压成形工艺,重点论述了其工位设计、排样图设计、模具总体结构设计。对8处90°的弯曲边,采用预弯曲再弯曲的工艺方法,导正销精密定位,多种结构形式的凸凹模设计方法,介绍了高速精密多工位级进模具制造中的关键技术。实践证明,该模具结构合理可靠,制件质量稳定,生产效率高的特点,对此类零件的级进模设计有一定的参考价值。     

鱼钩状接线片多工位级进模设计

在对一鱼钩状接线片的冲压成形工艺进行充分分析的基础上,从几种可行的加工工艺方案中得出一种符合制件特点的最佳方案,设计了冲孔、切边、打扁、多道弯曲成形、落制件、切断的14工位级进模。介绍了排样设计中的展开设计及排样重点考虑因素,给出了多工位级进模的装配图并着重阐述了模具的结构特点和主要零件的设计,模具投入实际生产后使用正常,制件质量符合用户图纸要求,可为同类制件的成形提供一定的参考。     

Type-C外壳成形工艺及级进模设计

级进模冲压成形是一种高效、高品质的金属板料塑性成形工艺方法。研究了TypeC外壳的成形工艺,详细介绍了级进模排样方案,确定了级进模总体结构和关键工位的详细结构设计。该模具结构设计合理、工作稳定、可靠,可完全保证制件质量,能够满足大批量生产需求。     

负极片多工位级进模设计

分析了负极片冲裁、弯曲成形工艺,介绍了排样方案、级进模总体结构。采用倒冲弯曲模结构解决了制件向上弯曲问题,采用补偿法及弯曲校正工序达到了控制制件弯曲回弹的目的。实践证明:模具结构可靠,加工质量好,生产效率高,对此类零件的级进模设计有参考价值。     

订书机支架自动出件级进冲压模具设计

根据订书机支架的材料、结构特点和尺寸精度要求,分析其冲压成形工艺性能,完成冲压工艺方案和模具结构的设计。确定订书机支架采用多工位级进模来成形。详细介绍了模具的主要结构特点及工作过程。根据零件结构特点,选择纵向排样进行设计,该排样方案包括冲孔、空工位、端部弯曲、空工位和切断、侧边弯曲5个工位。为了配合自动送料装置,模具设计了自动出件装置,采用楔形滑块结构,利用开合模动作,实现对成形件的自动推出;另外,为了保证条料的顺利送进,模具设计了浮顶装置。结果表明:采用多工位级进模成形订书机支架,可满足该零件所有特征的成形要求,实现高质量、高效率的冲压生产。     

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.