外壳胀形与镦压及口部倒角成形模设计

叙述了外壳胀形、镦压及口部倒角成形的复合工艺,将原工艺的胀形、镦压及车削口部倒角3个工序合成1副复合模完成制件的成形,减少了1副单工序模及一道机加工工序。重点介绍了制件胀形、镦压及口部倒角成形复合工艺的工作过程及模具结构特点。生产实践表明,模具结构紧凑,生产出的制件合格,质量稳定性好,提高了生产效率,降低了冲压成本,对类似制件的模具结构设计具有一定的借鉴作用。     

座椅座盆拉深复合成形工艺及模具设计

对某车型座椅座盆结构进行分析,制定了两工序拉深复合成形工艺,并开发了相应的成形模,可一次定位成形大深度的凸凹形状,通过将拉深深度和翻边高度进行协调设计,避免了拉深深度过深而产生开裂和翻边高度过高引起的起皱。该工艺减少了成形工序数、模具副数和2道拉深工序间的研配工作,提高了生产效率和材料利用率。     

压缩机上外罩制作的工艺实施

为了制作合格的上外罩零件,对其结构、成形工艺难点和工序内容进行了分析,确定了落料拉深、冲凸台、车边、冲孔、整形、压印等8道制作工序.结合冲压模具设计的知识和经验,设计了1副复合模和各单工序模,并对每1道制作工序和各模具工作过程进行了详细的阐述.为了保证车边工序的质量,设计了1副车边夹具,并对夹具的工作原理进行了详细说明...     

排气罩的工艺分析与模具设计

通过分析排气罩的材料、数量、结构和工艺性,确定了此零件采用单工序模进行生产。设计了制件生产的工序图:工序1下方形料;工序2预拉深得到底部凸起位置;工序3激光切割翻边预制孔;工序4拉深翻边成形,得到翻边和下陷形状;工序5切边钻孔,完成制件。本次设计通过试压给出合格的展开件,使用展开毛料边缘定位,凸模与压边圈之间、压边圈与上模之间均采用导滑板的方式进行导向,定位精度高,以此实现了拉深翻边的准确加工。模具工作时安置调压垫调整压边力,设置镦死垫,避免了模具因受到巨大的冲击而导致的疲劳损伤。以CATIA为辅助工具,设计出拉深翻边成形所需的凸模、凹模以及压边圈,对模具零部件进行装配,得到拉深模具的装配体的三维数模。同时,介绍了覆盖件拉深模结构设计要点。通过实践验证,所设计的模具工艺性良好、结构合理、符合生产要求。     

车轴盖复合模设计

分析了1副复合模实现落料、拉深、冲孔、翻边4道工序一次冲压成形的工艺性,解决了车轴盖冲压成形一般需要4副模具完成的问题。同时还介绍了复合模结构设计思路及装配工艺方法,突破了复合模只能完成3道工序的方法,在模具结构设计上有所创新,并给出此类模具设计中结构参数的计算方法,生产的零件符合要求。     

家用电器管壳拉深模设计

通过对某家用电器管壳进行工艺分析及详细计算,设计了1副毛坯落料级进模和7副单工序模,主要介绍了拉深工序的模具结构特点及工作过程。实践证明,模具结构合理,加工质量稳定,对同类制件的模具设计有一定参考价值。     

圆筒形拉深挤边级进模设计

叙述圆筒形零件连续拉深的工艺及计算,重点介绍最后一次拉深带挤边的过程及特点,设计了圆筒形件拉深-挤边级进模,分析了模具结构及各参数对零件质量和模具寿命的影响。实践证明:模具质量稳定,生产的零件符合要求,可为类似拉深件的模具设计提供参考。     

电压力锅内胆冲压模具结构

结合冲压模具的知识,对电压力锅内胆的尺寸、结构和材料厚度进行了分析,经计算后,判断所提供的图纸不符合拉深模具的要求。在不影响产品整体结构的情况下对产品图作出适当的修改,并结合以往开发类似模具的经验,设计了落料、拉深1、拉深2+翻边1、翻边2这4套工序模具,其中,3套模具为单工序模,一套模具为复合模,详细地介绍了4套工序模具中主要零件的计算过程,同时根据冲裁力或拉深力的大小,结合模具的尺寸、安全生产要求和压力机的实际规格,选用合适的压力机,并详细介绍模具的工作过程。     

汽车覆盖件多工位复合成形工艺研究及模具设计

以某汽车覆盖件为例,首先对其冲压工艺进行研究,确定其工艺方案为:拉深、修边冲孔、修边、二次修边冲孔、翻边整形、侧冲孔及剖分6道工序,其中第1道工序采用两制件合并拉深,且进行对称拉深成形,即采用"一出二"的形式,既提高了制件成形精度和表面质量,也提高了生产效率;再对制件进行模具设计,将修边+冲孔、修边两工序设置在同一副模具中,将二次修边+冲孔、翻边+整形、侧冲孔+剖分3个工序设置在同一副模具中,即采用多工位复合冲压模具,则可明显减少模具的数量,从而减少了成形设备和操作工人的数量,提高生产效率且降低生产成本。     

筒形件冲压工艺分析及模具设计

分析了某筒形件的冲压工艺,在原成形方案的基础上将落料与拉深工序复合、胀形与冲孔工序复合,节省了1副模具,并介绍了工件胀形、冲孔分步式复合模的结构及主要零件的设计。实践证明,该模具结构合理,生产的工件满足使用要求。     

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.