运用均衡凝固理论设计铸铁件升降平台的浇冒口系统

橡胶机械产品胶片机升降平台,材质HT200,重85 kg,由260/110mm×75mm圆环体与400mm×400mm×40mm方板相接组成.为防止环板交接处的收缩缺陷,采用圆环体在下、方板在上的浇注工艺.侧注式浇注系统,在浇注系统对侧安置补缩-溢流冒口.运用均衡凝固收缩模数法设计冒口尺寸,用大孔出流理论设计浇注系统.设计结果:直浇道φ35 mm,双向横浇道24/27 mm×28 mm,4道内浇道10/12 mm×34 mm,浇口截面比∑A直∶∑A横∶∑A内=1.0∶1.5∶1.6.两只冒口φ70mm×130mm,冒口颈厚7 mm,长8 mm.生产表明铸件上表面光洁,无气孔,渣孔缺陷,机加工后铸件没有缩孔、缩松缺陷,工艺出品率88.5％.证明采用均衡凝固技术设计的浇冒口系统是可靠的.     

运用大孔出流理论设计磨齿机床身底注式浇注系统

Y7163-10-102磨齿机床身,材质HT200,轮廓尺寸1275mm×680mm×620mm,主要壁厚20mm,最大壁厚55mm,铸件重1300kg,树脂砂型。运用大孔出流理论,设计底注式浇注系统,1个直浇道,直径φ55mm,2个横浇道,截面38mm×40mm,14个内浇道,截面29mm×8mm。浇道比为A直∶∑A横∶∑A内=1.0∶1.2∶1.4。铸件顶部放2只侧冒口,直径φ80mm。实测浇注时间80s,型腔金属液面上升速度8mm/s。生产结果表明:铸件形状完整,轮廓清晰。机加工后,铸件没有缩孔、气孔、渣孔缺陷,达到技术要求。     

铸铁件浇注系统撇渣能力的探讨

介绍了铸铁件常规浇注系统的结构形式,分析了撇渣的必要条件、充分条件以及浇注系统结构对撇渣能力的影响。最终得出如下结论:(1)浇注系统应尽可能营造层流流动或降低紊流度;(2)横浇道充满是撇渣的必要条件;(3)在进行浇注系统结构设计时,应避免内浇道设在横浇道顶面和离横浇道末端太近,直浇道中心至第1个内浇道中心的距离也不能太近;(4)增加浇注系统长度、采用多组元浇注系统以及设置直浇道窝等均有利于减小铁液紊流,从而有利于夹渣和气体与金属液分离并上浮。     

轮形铸铁件补缩式雨淋浇注系统的设计

采用上雨淋浇注系统生产轮形铸铁件,将直浇道、横浇道当冒口,内浇道(雨淋孔)当冒口颈,采用均衡凝固收缩模数法设计其尺寸,浇口兼作冒口,完成充填与补缩双重作用.对材质为HT250,轮廓尺寸φ600 mm×601 mm,轮缘厚61 mm,轮毂厚71 mm,轮辐厚50 mm,重920 kg的BA36050皮带轮,采用直浇道φ50 mm,横浇道50/60 mm×55 mm,内浇道(雨淋孔)φ20 mm(5只)的浇注系统.经批量生产验证,铸件无铸造缺陷,达到技术要求,工艺出品率97%,成品率大于97%.     

外环内浇道转子压铸模设计

浇道设计外环内浇道转子制件简图及浇注系统的结构见图１。转子模具在卧式压铸机上使用，横浇道为环状，在横浇道圆周上分布了内浇道。该内浇道的设计优点是与转子槽形距离近，便于迅速填充型槽，减少铝液在填充过程中的热量损失，减少转子铸铝的废品率。内浇口厚度一般为１～１．５ｍｍ，长度３～４ｍｍ。内浇口截面积的计算公式：Ｆ内＝Ｑ／（γｖＴ）式中Ｆ内———内浇口截面积，ｃｍ２Ｑ———转子用铝重量，ｇγ———铝液的密度，２．４ｇ／ｃｍ３ｖ———内浇口处金属液的流速，１２００～３０００ｃｍ／ｓＴ———充填型腔的时间，…     

148电机线圈支架灰铸铁件顶注压边浇冒口工艺的设计

148线圈支架上下为圆环,由中间9个腰肋连接,最大壁厚40 mm,铸件重70 kg,材质HT 150,普通粘土砂,水平三开箱造型。运用大孔出流理论设计了顶注压边浇冒口系统。直浇道直径φ35 mm,横浇道尺寸24/28 mm×26 mm,内浇道由截面为37/39 mm×6 mm的2道内浇道和2个压边冒口形成的55 mm×5 mm的压边缝隙合成,浇道比为A直∶A横∶A内=1.0∶1.4∶1.1。用收缩模数法设计冒口,冒口直径φ55 mm、高90 mm,设1只φ30 mm的排气耳冒口。首批生产30件,经检查无缩孔、气孔、夹砂等缺陷,铸件经加工后,全部合格,表明运用大孔出流理论设计浇注系统,采用顶注压边浇冒口填充补缩工艺,生产148线圈支架铸件是可行的。     

超超临界汽轮机中压外缸铸件浇注系统的设计

介绍了中压外缸铸件的结构以及其浇注系统设计.采用半开放式浇注系统,最小截面设置在分直浇道,各组元截面积比为F直1∶F横1∶F直2∶F横2∶F内=1.2∶1.34∶1∶1.07∶ 1.24;内浇道做成宽度逐渐扩大形,开设在下型3只轴孔处.采用华铸CAE凝固模拟软件分析浇注动态过程,结果表明充型较为平稳;铸件尺寸检验和UT检测显示铸件符合客户要求.     

汽车活塞浇注系统的改进及数值模拟

采用Anycasting模拟软件研究了不同浇注系统对汽车活塞顶部缺陷的影响。通过对浇注系统的改进,包括增加浇注系统直浇道和双侧内浇道的横截面积,增大浇口杯横截面积和冒口的尺寸,将浇注系统和冒口整体化,实现了金属液的补缩从零件上表面推赶至冒口和浇注系统中,减小了金属液在充型过程形成的内压,解决了金属液进入内浇道时紊乱充型的问题,使得活塞顶部形成的缩孔缺陷消失。提高了生产率,为实际生产提供了指导。     

新型浇注系统与充型过程的计算机模拟

对比模拟了新型浇注系统与传统浇注系统的充型过程,包括金属液在浇口杯、直浇道、横浇道和内浇道中的流动情况。基于新型浇注系统设计原则设计并模拟了摇枕铸件的充型过程,模拟结果进一步证明了新型浇注系统充型平稳,浇道处于充满状态,避免了气体和夹杂卷入型腔。     

前叉下管铸件的铸造工艺设计

介绍了前叉下管铸件的结构及技术要求,详细阐述了其铸造工艺设计:采取垂直分型,膨润土湿型砂造型;采用底注式浇注系统,圆锥形直浇道的截面面积为972 mm2,横浇道与直浇道、内浇道相连接,横浇道为截面积1 200 mm2的标准梯形浇道,内浇道的截面面积为420mm2,选用六角形浇口杯,浇注速度为8.12kg/s,浇注时间为5s,浇注温度为1580℃;采用12个尺寸为30mm×60mm×75mm的冷铁,选用腰形暗冒口,尺寸为a=50 mm,b=100 mm,h=100 mm;选择扁形出气孔。模拟结果显示,整个铸件未发现有缩孔、缩松等铸造缺陷,而且工艺出品率也达到了76.53%。     

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

正~~     

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.