SZ—400／1600注塑机液压系统的改进设计

近代注塑机液压系统的主要特点是:高效、低能耗、低噪声。还必须使液压系统的价值高,即功能与成本之比要高。只有这样,才能在市场上具有竞争能力。 SZ-400/1600注塑机是测绘国外样机,1982年试制成的,84年被评为部优质产品及上海市创优赶超产品。随着对注塑机设计认识的深化,根据用户在使用中反映的问题,迫切需要对该机的液压系统进行改进设计。围绕“减少能耗、降低噪声、提高效率、节约成本”等四个方     

基于AMESim的注塑机锁模系统设计与仿真

节能、高效是当今世界注塑机的发展方向,使用电液伺服技术的电液混合注塑机就是其中重要的一个分支.在一款精密电液混合注塑机的研制过程中,针对该注塑机锁模系统进行了深入分析,利用AMESim系统仿真软件建立了注塑机锁模单元的电液伺服系统模型,根据生产实际需求对该系统模型进行了压力和速度的仿真,分析了引起锁模液压系统压力、速度波动的原因并提出了改进方案.仿真结果表明:系统设计合理,为电液混合注塑机的进一步研制奠定了基础.     

XS-ZY-250A型注塑机液压系统故障诊断

简要介绍XS-ZY-250A型注塑机的液压系统工作原理,利用取消法检测液压系统中存在的故障并及时排除,为解决同类型设备液压系统的故障提供参考。     

液压活塞式压缩机液压系统的优化改进

针对L型液压活塞式CNG子站压缩机在往复压缩天然气过程中,液压系统存在着换向冲击、噪声值大(90～106 d B(A))以及换向不稳定等现象,通过建模仿真与模拟样机试验相结合的方法,得到该液压系统的动态性能参数,对影响其动态性能的特性参数进行深入的研究,提出该液压系统的优化改进措施,完成了改进后液压系统的设计与研制,并对改进后的样机进行相关的试验与动态测试。结果表明:改进后的L型液压活塞式压缩机液压系统的换向冲击显著减弱、工作噪声不高于90 dB、系统油温升不高于55℃,整机的工作性能得到较大提升。     

注塑机能量损失分析及节能发展方向

在注塑机节能的研究中,能量损失分析是一个重要的组成部分。注塑机最主要的能量损失来自于驱动系统和液压系统的能量损失。详细分析了驱动系统的电机和泵的能量损失原理,主要包括泵自身的能量损失和电机与泵匹配的能量损失;并对液压系统中的能量损失进行分析。最后对注塑机节能发展的方向和发展趋势进行了预测。     

小型注塑机液压驱动方式探讨

通过对小型注塑机液压系统进行分析,提出几种切实可行的液压驱动系统设计方案,并分析了每种方案的优缺点.     

基于工艺流程的液压注塑机的变频节能控制研究

针对目前注塑机液压系统使用定量泵加双比例阀结构普遍存在的较大的溢流损失等问题，提出了在原有阀控液压调速系统基础上利用变频技术实时控制液压泵输出流量的系统结构，并阐述了其工作原理。在此基础上，针对注塑机液压系统的特殊性，提出了基于工艺流程的控制方法，在保持原有阀控调速系统频响的前提下，大幅度降低了注塑机液压系统的溢流损失，因此节约了注塑成本。     

ST-2500型注塑机的润滑系统数控改造

对ST-2500型注塑机润滑系统各润滑部位采用的手动控制液压油泵方法,进行数控自动化改造,并介绍润滑系统的构成及特点、润滑原理及工作时要注意的事项.新的润滑系统极大地解决了困扰工厂多年的难题,在生产中取得良好的经济效益.     

法兰注塑模设计方案的改进

在对法兰注塑模设计方案进行分析的基础上,对其进行了改进,加长了斜导柱,将模具的项出机构与注塑机的液压项杆连接。改造后的模具,延长了使用寿命,提高了产品质量。     

恒压变流量供油注塑机液压系统的研究

低能耗是注塑机液压系统的一个发展趋势,而目前注塑机液压系统采用的定量泵供油导致系统能耗非常大。介绍了注塑机的定量泵供油与恒压力变流量液压泵供油系统的工作原理,并建立恒压力变流量液压泵供油系统的仿真模型,分析其能量消耗的过程,实现注塑机低能耗工作。     

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.