铝挤压工模具技术的发展

简要地论述工模具在铝合金挤压生产中的重要作用与特殊地位;介绍铝挤压工模具技术的主要内容;着重分析了国内外挤压工模具设计制造水平及创新亮点,铝挤压工模具的使用、修理、氮化技术及现代化管理工具.     

基于UG的铝型材挤压模具CAD设计系统

铝合金型材的巨大需求和产品的多样化对挤压模具的质量和设计制造周期提出了更高的要求,使用CAD/CAE/CAM技术是提高挤压模具质量、缩短设计制造周期的有效途径.但是由于挤压模具结构复杂、单件生产的特性,目前还没有商业的挤压模具设计专用CAD系统.本文融合了实际工程经验,开发了基于UG系统的挤压模具设计专用CAD系统,实现了工作带的自动设计,通过有限元的模拟分析,结果表明,该系统能够设计出比较合理的挤压模具,并且能够提高模具设计的效率.     

铝合金挤压模具寿命影响因素

挤压模具的寿命是一个综合性的技术问题,它涉及模具设计、模具材料、制造加工、热处理、表面处理、挤压工艺、模具修理、模具的科学管理等诸多方面。本文在实际生产经验的基础上,阐述了模具设计、选材、热处理和表面硬化处理,以及模具使用、修理和维护保管等因素对挤压模具使用寿命的影响。影响模具寿命的因素很多,只有在理论和实践方面系统而深入地研究模具的工作条件、失效特性和原因,从模具设计、模具材质、热处理、加工、验收、制定合理挤压工艺、模具修理以及科学管理等全过程进行认真研究,     

发射器用大型散热器挤压模设计

通过典型的大型散热器型材的挤压模具设计实例,阐述了模具结构特点、模具加工、生产时采取的措施、挤压结果以及模具的改进情况。     

带筋宽幅铝型材挤压模具仿真与优化

针对带筋宽幅铝型材挤压模具,采用HyperXtrude有限元仿真分析方法,通过仿真建模与计算,分析了型材流速、型材变形和模具应力分布情况,并对模具结构参数进行优化设计。结果表明,结构优化后的带筋宽幅铝型材挤压模具符合生产要求。仿真与优化技术的应用极大地缩短了模具开发周期,提高了模具设计水平。     

温挤压模具寿命影响因素分析及改进措施

系统分析了温挤压模具服役条件和影响模具寿命的各种因素,从模具设计、选材、润滑、表面强化处理等方面,阐述了提高温挤压模具寿命的措施.     

沈阳新鑫模具有限公司

正科研专利:金属挤压圆(扁)挤压筒,圆(扁)固定弹性挤压垫赵云路科研专著:"中国模具设计大典挤压工模具篇","铝塑型材挤压成型技术","铝型材工模具设计","金属挤压工模具手册"。金属挤压工模具获奖项目:国家级科学技术进步二等奖:大型铝合金型材挤压成套工模具设计制造技术与应     

铝合金宽幅带筋型材挤压模具优化设计

优化船用铝合金带筋宽幅型材挤压模具结构，对不同模具设计方案进行讨论分析。利用有限元分析软件HyperMesh进行数值模拟，获得挤压过程中模具位移及应力场的变化规律；结合工程实验，验证模具设计方案的可行性；调试相应挤压生产工艺，对挤压设备进行配套改造，得到最优模具结构。结果表明，采用无缝管挤压模具方案进行生产，可得到一体成型的尺寸较大、性能较好的带筋型材。     

影响铝型材挤压模具寿命因素的分析

在铝合金建材与工业型材生产中,延长挤压模具寿命是提高生产效率,降低生产成本的关键环节之一。本文综述了铝合金挤压模具的失效形式,并从模具材料选择、模具设计、模具热处理与模具渗氮方面分析了影响铝合金模具寿命的各个因素。     

影响挤压模具寿命的因素

挤压模具对实现挤压过程有十分重要的作用阐述了模具设计，选材，热处理和表面硬化处理，以及模具使用，修理和维护保管等对挤压模具使用寿命的影响。     

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.