周期轧机喂料器液压伺服系统滑阀受力特性的分析

<正> 我厂216车间2~#周期轧机喂料器是从西德米尔公司引进的设备。其进给控制采用的是目前较为先进的液压伺服控制装置(图1)。在使用中发现,该液压伺服系统的滑阀操纵手柄在工作中不能准确仃在规定的工作位置,出现手柄的反弹和顺弹现象,从而引起整个系统的工作参数发生振荡,或误动作。下面仅就滑阀操纵手柄的反弹和顺弹问题对该系统的滑阀受力特性进行一些分析和讨论。     

液力缓速器液压控制系统设计

液力缓速器体积小,安装方便,在车辆中的使用越来越广泛。设计一种小型液力缓速器及其液压控制系统。该控制系统整体结构简单,布置紧凑,操作方便,在小型车辆上也适用。采用转阀改变缓速器进、出油口通流面积,控制缓速器的制动力矩。转阀具有结构简单、响应迅速且液动力小等优点。该液力缓速器及其控制系统能为小型车辆提供稳定的辅助制动力,并实现多挡位精确控制。     

一种液力变速器一档起步缓冲装置

在不改变铁路轨道车用液力变速器原有性能和单级两相三元件液力变矩器结构的基础上,通过加装变矩器离心单向阀和供油控制阀,实现了对变矩器充、放油的控制和对变矩器输出力矩的控制,使液力变速器在一档起步和空档运行过程中输出力矩平稳上升,实现铁路轨道车的平稳起步,消除了起步冲击和空档走车现象,大幅度提高了舒适性和安全性。该缓冲装置结构简单、性能可靠、操作方便,还能够广泛应用于其他特种车辆。     

新型牵引-制动型液力变矩器液压系统动态性能仿真研究

基于对某新型牵引-制动型液力变矩减速器的结构和特性分析,建立了其电控液压系统的AMESim仿真模型.通过仿真,研究了其在闭锁过程和制动过程压力动态变化性能.仿真研究表明,特殊设计的液压系统实现了良好的缓冲闭锁过程.     

电液比例控制技术在伸缩臂叉车中的应用研究

介绍了基于电液比例控制技术的伸缩臂叉车液压系统的构成,并对该液压系统进行了负载敏感及压力补偿分析.采用电液比例控制阀可简化伸缩臂叉车液压系统结构,实现伸缩臂叉车工作装置运动速度的连续、比例控制,可提高系统的控制精度和效率,实现系统节能和智能化作业.     

汽车液力缓速器恒速控制策略仿真研究

加装液力缓速器汽车恒速下坡控制是一个时变、非线性控制过程。为使汽车恒速下坡控制满足无静差、响应快的要求,通过分析液力缓速器控制特性与模糊控制特点,提出采用分级变论域模糊控制策略实现汽车恒速下坡控制。采用MATLAB/Simulink建立重型汽车下坡动力学模型和分级变论域模糊控制器,对汽车恒速下坡控制进行仿真分析,并与常规模糊控制算法控制性能进行比较。研究结果表明:分级变论域模糊控制算法能满足汽车恒速下坡控制性能要求,控制效果明显优于常规模糊控制。     

摩擦压力机操纵装置

摩擦压力机操纵装置，属于锻压机械领域，其特征在于：是由控制系统、执行系统组成的电操纵装置，控制系统由手柄，传感器，电机控制器组成，手柄与传感器相连，传感器与电机控制器相连，执行系统是由偏心部件，减速机，连杆，电机组成，电机与减速机相连，减速机与偏心部件、连杆相连。具有能耗低，可降低80％，操纵装置更协调、灵便，噪音低，改善工作环境，因避免了空气压缩机运行时产生的噪音及排放废气造成的扬尘现象等优点。     

荷马特发布一款能满足任何作业高度的多向旋转式冒口分离器

<正>虽然铸造厂工作方式的多样化,但每个铸造厂都需要一款能适合且满足他的工况的工具。荷马特新款多向旋转式冒口分离器可以满足你在任何作业高度使用,而且最大化降低重新调整铸件位置工作量。从而大大减轻现场工作人员的工作强度,作业时更安全、轻松。这款独特悬挂系统结构设计,从而使得分离器可以很容易简单的定位且符合人体工程学,满足任何方向的作业要求,包括垂直。采用手柄设计操作手柄,使得分离器在水平、立     

300吨摩擦压力机油压操纵装置的改进

用油压操纵装置控制摩擦盘作用到飞轮上的压紧力,具有轻便、可靠等优点,因而得到广泛采用。但也普遍存在着油压系统发热严重,工作稳定性差;当手柄处于停止工作位置时,飞轮不易与左右二摩擦盘同时分开等毛病。     

挖掘机的操作与检修(2)

第三节手拉杠杆操纵系统不经常动作部位的控制用手拉杠杆来操纵。如行走拐弯、铲臂的升降、行走和回转的更换等。图3为三个手拉杠杆传动示意图。它们的共同特点是操纵手柄处有限位板(10、16、17),长期放置不改变位置。操纵拉杆都有螺纹,可调节其长短,接触部分都类似一般离合器结构的卡环和滑块。手柄1、拉杆2、拉臂3、扁担4是控制     

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.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

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.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.