轴壳扩径、缩口复合模设计

针对轴壳扩径、缩口的成形特点，在进行工艺计算的基础上确定了合理的工艺方案，设计了扩径、缩口复合模。根据试模中出现的缺陷，分析了产生的原因，改进了模具，生产出了合格的零件。     

管坯推压缩径端部翘曲机理及其影响因素分析

基于对管坯推压缩径的理论分析、试验研究和数值模拟,揭示出缩径时管坯端部存在翘曲的主要原因:管坯内外层缩径量不均匀,使得内层的轴向变形大于外层,导致变形后的管坯端部产生刚体转动,使其外径大于凹模出口处内径,产生翘曲,而且翘曲区的长度近似等于最初位于凹模锥口部分坯料流出后的长度;并分析了缩径率、缩径凹模半锥角、摩擦系数、缩径管坯初始壁厚对管端翘曲和轴向伸长率的影响规律。     

5A02铝合金薄壁管材热挤压缩径增厚成形试验研究及优化

为解决某型飞机拉杆缩径端部直接攻螺纹的问题,首次提出了5A02薄壁铝合金管端热挤压缩径增厚成形方法,设计并制造了成形模具。研究了增厚区直段尺寸、模具肩部长度与模具锥角对薄壁管热挤压缩径增厚行为的影响,并优化了成形工艺路径。试验结果表明:增厚区直段长度和外径过大易导致直段部分失稳起皱;模具肩部过长,材料易在支撑区产生堆积且易出现失稳屈曲,在满足管材可预热的条件下,模具肩部长度应越短越好;采用模具锥角为12°和16°的凹模单道次热挤压成形时,位于缩径区域的管材易出现起皱,且增厚区径向增厚不明显;采用先大锥角后小锥角两道次热挤压成形后,成形件缩径段径向尺寸由1. 00增至4. 06 mm,增厚率为306%,成形效果良好。     

常规挤压与缩径挤压的变形规律及工艺设计

围绕常规正挤压与缩径挤压原理相同但特点各异进行两种挤压工艺及模具的详细比较,给出了两种挤压的变形规律及常规正挤压工件前端出现"外凸"和缩径挤压工件前端出现"内凹"的形成机理;提出采用经验与理论相结合的两种挤压工艺的设计方法;以变速器输入轴为实例,进行多工步缩径挤压工艺试验,验证了理论研究结果的可行性,为两种挤压工艺的推广及应用提供了参考。     

等速万向节外套缩径模具模芯运动分析

用运动学方法分析了等速万向节外套缩径模具的可行性。计算出凸模锥面角度值，给出凸模径向运动方程式及弹簧力表达式。     

杵环杆镦锻模设计

根据杵环杆结构特点,分析了零件成型工艺,介绍了模具型腔结构及其整体结构设计,阐述了模具工作过程,进行了锻压力和模具主轴行程的计算,设计的模具在普通压力机上即可实现长杆类零件的头部成型,解决了零件杆部太长以致头部成型困难的问题,降低了生产设备要求,节省了制造成本。     

大高径比凸台缩径—冷镦成形工艺方案研究

针对大高径比凸台冷镦粗成形易出现失稳的问题,制定出缩径预成形、冷镦终成形的工艺方案.并通过Deform-3D软件模拟了缩径和冷镦成形过程,研究了坯料直径和入模半角对成形质量及成形力的影响.数值模拟结果表明,采用缩径—冷镦工艺方案可避免镦粗失稳缺陷的产生.工艺试验表明,试验结果与数值模拟结果一致.数值模拟结果对工艺试验有一定的指导意义.     

汽车桥壳管坯推压缩径工艺研究

基于动力显式有限元软件,以汽车桥壳管坯为例,分别开展了1道次和2道次推压缩径成形工艺的数值模拟,并对缩径区典型截面的壁厚分布、端部翘曲、轴向失稳等影响成形质量的因素进行了分析。模拟结果表明：采用2道次的缩径成形工艺明显要优于1道次直接成形。成形件不仅满足使用要求,而且缩径过程中模具最大载荷为360kN,对模具的损耗尽可能地降低到最小程度,有利于降低生产成本,并对随后成形出合格的桥壳胀形件奠定了基础。     

桥管缩径工艺的改进

介绍了在液压机上进行桥管缩径工艺及模具的改进。运用改进后的工艺及模具压制桥管,提高了产品合格率和模具使用寿命。     

缩径区长度对粘性介质外压缩径成形的影响

粘性介质外压缩径采用半固态、可流动、高粘度和一定速率敏感性的高聚物作为缩径用传力介质,有效地解决了缩径成形过程的失稳起皱问题,提高了坯料的极限缩径量.本文针对不同缩径区长度对粘性介质外压缩径过程的影响问题,采用试验和有限元方法进行了分析,得到了不同缩径区长度条件下1Cr18Ni9Ti薄壁管的极限缩径量及应力与应变的分布规律.研究结果表明,缩径区长度对粘性介质外压缩径成形影响较大,缩径区长度越短,坯料的抗失稳起皱能力越强,极限缩径量越大.     

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.     

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.     

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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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.