局部偏心形状零件的精密塑性成形技术研究

局部偏心形状零件结构比较复杂,广泛应用在机械传动中。本文根据该偏心形状零件结构特点,制定了冷温复合精密塑性成形工艺方案。重点设计了偏心冷镦挤预成形工序及温镦挤终成形工序,设计了偏心镦挤和等温镦挤模具,选择了合理的坯料润滑、模具预热及冷却条件,并进行了偏心形状零件的精密塑性成形实验。实验结果表明,采用该工艺及模具可以生产出尺寸精度较高及力学性能优良的偏心形状零件,且材料消耗少、生产效率高,具有较高的经济实用价值。     

套筒冷挤压缺陷分析及优化设计研究

冷挤压是一种非常先进的绿色加工工艺,适合传动零件的坯料加工。冷挤压过程由于坯料变形大、材料流动复杂,模具和坯料设计难度大,常会发生各种缺陷。以套筒冷挤压为例,根据套筒的零件技术特征,确定了零件的冷挤压方案,并设计了挤压模具。基于数值模拟对零件成形过程的开裂缺陷进行了分析,采用材料跟踪和剖面对比的方法进行了模拟和试验比较,发现开裂的原因是由于毛坯的开孔过大导致孔边缘折叠形成了裂纹源。对开孔尺寸进行了优化,成功消除了开裂缺陷,得到了最佳的成形方案。     

多向加载近净成形研究动态

通过主动控制不同方向、不同成形阶段的多向加载条件并配合模具、变形温度等成形条件,可有效控制变形,提高坯料的成形性能,以获得预期的结构形状及组织状态的零件,实现净成形或近净成形,为难变形材料的复杂整体构件的精确塑性成形提供了一条有效途径。多向加载技术在蒙皮拉形、管材挤胀、环件径轴向辗扩、多向模锻等塑性成形工艺中都得到体现,但其工艺通用性差,需要专门的设备,不同成形工艺甚至当成形零件不同时,其变形机理亦迥异。评述了目前多向加栽成形工艺的应用与国内外研究现状,指出了该工艺在体积成形中应用发展需要解决的关键技术问题。     

杯形件温挤成形工艺参数的模拟与试验分析

通过模拟软件分析和试验验证,定量地分析了杯形件温挤成形时挤压温度、摩擦条件、坯料形状与尺寸等工艺参数对挤压力、模具寿命以及零件质量等方面的影响,从而为温挤成形工艺参数的合理制定提供了一定的参考依据。     

内螺旋状零件冷挤压成形过程数值模拟及参数优化

对内螺旋状零件的冷挤压成形过程进行数值模拟,系统地研究了摩擦系数、螺旋角和挤压角等因素对内螺旋状零件冷挤压成形过程中凸模所受挤压力和成形缺陷的影响,并对挤压成形工艺参数进行了优化.研究结果表明:摩擦系数、螺旋角和挤压角等因素对内螺旋状零件冷挤压成形过程中挤压力存在显著的影响.随着摩擦系数的增加,挤压力呈线性增加;随着螺旋角和挤压角的增加,挤压力呈非线性增加.摩擦系数和螺旋角等对内螺旋状零件的冷挤压成形缺陷影响较大,而挤压角的影响较小.采用优化后的工艺参数对内螺旋状零件进行了冷挤压成形实验,获得了合格的制件.本文的研究结果为内螺旋状零件的冷挤压成形提供了工艺指导,具有实际的应用价值.     

GH4169合金零件的冷挤压成形工艺

提出了一种GH4169合金零件冷挤压成形的工艺路线,以达到提高零件力学性能、降低生产周期和成本的目的。通过试验,总结出一套专门用于GH4169合金零件冷挤压成形的坯料表面处理方案,经过此方案处理后,坯料对润滑剂的吸附能力得到明显提升,降低了坯料与模具间的摩擦力,起到了很好的保护润滑作用。采用分步优化的方法,设计并优化了冷挤压模具结构,大幅度提高了模具寿命。最终,通过冷挤压试验,成功挤压出性能优良的GH4169合金零件,其变形程度最高可达62%,抗拉强度可提高至1773 MPa,较冷挤压前提高约1倍。证明了GH4169合金零件冷挤压成形工艺的可行性和优越性。     

两出口环形件的冷挤压成形工艺研究

针对两出口环形件的形状特点,确定了冷挤压成形的方案,设计了零件挤压成形图,校核了挤压工序的变形程度。采用等应变分配原理,得出了分流层直径的大小,并进行了成形力和坯料尺寸的计算。冷挤压成形试验表明,采用冷挤压工艺确保零件的尺寸精度,实现了空调压缩机罩体零件的工程化批量生产,创造了可观的经济效益。     

厚料窄边圈类止动垫圈零件冲压成形工艺仿真及模具设计

以航空发动机用不锈钢止动垫圈为典型研究对象,针对采用常规冲压成形方法零件精度低的问题,结合实验和有限元仿真分析,研究了高强度材质厚料窄边圈类零件冲压成形的特点、变形规律及尺寸误差来源、缺陷形成机理及避免措施,制定了合理的冲压工艺及模具方案。结果表明：两步法级进冲裁是获得高精度厚料窄边圈类零件的有效工艺方法,凹凸模间隙是影响零件塌角高度的重要因素,半冲裁过程施加下顶力可有效避免因外圈失稳变形引起的塌角和内径尺寸偏差。通过设定合理的模具间隙、下顶力、半冲裁厚度等关键参数,获得了符合设计图纸质量要求的止动垫圈零件。     

机车启动齿轮坯加工工艺

通过对启动齿轮成形工艺进行分析,提出了采用冷镦成形齿形外圆和冷挤压花键成形工艺;介绍了变形程度计算,给出了坯料尺寸及挤压力的计算;对冷挤压花键模的设计做了介绍,其保证了该零件的顺利成形,为类似零件的制造提供参考.     

切挤复合精整成形参数对表面质量的影响

从切挤复合精整的变形特点入手,通过物理实验方法,分析了精整余量、主模具圆角半径等工艺参数和坯料材质、工件轮廓形状等因素对精整表面成形质量的影响,为实际生产提供了可靠参考。结果表明,精整余量和主模具圆角半径是影响成形质量的关键参数,对精整工艺存在交互影响;塑性好、精整余量小、材料厚度小、主模具圆角半径大时,切挤复合精整成形面折光亮带宽度就大;相同参数下,塑性好的材料容易获得好的表面质量,内凹轮廓比外凸轮廓更容易得到较高的成形质量;主模具表面质量对工件成形表面具有复印作用。     

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。     

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).     

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.     

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.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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