检索结果-南通市图书馆

Evaluation of the mold-filling ability of alloy melt in squeeze casting

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2006年第1期13卷 60-66页

作者： Haiying Zhang shuming xing Qinghua Zhang Jianbo Tan Wen Liu Semisolid Forming Research Center Beijing Jiaotong University Beijing 100044 China Shijiazhuang Locomotive Depot Shijiazhuang 050000 China Department of Material and Engineering Hebei University of Science and Technology Shijiazhuang 050018 China

The mold-filling ability of alloy mclt in squceze casting process was evaluated by means of the maximum length of Archimedes spiral line. A theoretical evaluating model to predict the maximum filling length was built based on the flowing theory of the incompressible viscous fluid. It was proved by experiments and calculations that the mold-tilling pressure and velocity are prominent influencing factors on the mold-filling ability of alloy melt. The mold-filling ability increases with the increase of the mold-filling pressure and the decrease of the proper mold-filling velocity. Moreover, the pouring temperature relatively has less effect on the mold-filling ability under the experimental conditions. The maximum deviation of theoretical calculating values with experimental results is less than 15%. The model can quantitatively estimate the effect of every factor on the mold-filling ability.

关键词： squeeze casting process parameters mold-filling ability theoretical calculation experimental evaluation

Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes PartⅠ: Energy Dissipation

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2007年第6期23卷 342-346页

作者： Wen LIU shuming xing Peiwei BAO Milan ZHANG Liming XIAO Beijing Jiaotong University Beijing 100044 China

The energy dissipation caused by the viscous force has great effects on the flow property of semi-solid metal during rheological processes such as slurry preparing, delivering and cavity filling. Experimental results in this paper indicate that the viscous friction between semi-solid metal and pipe wall, the collisions among the solid particles, and the liquid flow around particles are the three main types of energy dissipation. On the basis of the hydromechanics, the energy dissipation calculation model is built. It is demonstrated that the micro-structural parameters such as effective solid fraction, particle size and shape, and flow parameters such as the mean velocity, the fluctuant velocity of particles and the relative velocity between the fluid and solid phase, affect the energy dissipation of semi-solid metal.

关键词： Semi-solid metal Energy dissipation Rheology Apparent viscosity Model

Particle motion behavior during gasiication of foam carrier in lost foam-squeeze casting of 20%TiC/ZG270-500 composites

在线全文

学校读者我要写书评

暂无评论

China Foundry 2013年第6期10卷 367-373页

作者： Bin Shibo xing shuming Guo Lijun Bao Peiwei School of Mechanical ElectronicControl Engineering Beijing Jiaotong University

The particle motion behavior affects the distribution of particles in the metal matrix and finally determines the mechanical properties of the particle reinforced metal-matrix composites. To obtain a uniform distribution of TiC particles and excellent strengthening effect in 20%TiC/ZG270-500 composites fabricated by lost foam-squeeze casting （LFSC）, the particle motion behavior in the gas gap and the conditions of the particles getting into the molten steel were investigated. The results show that the airflow velocity （vl） and TiC particle motion velocity （up） change little with the pouring temperature （Tp）, increase with an increase in metal filling velocity （Vp）, ratios of cross sections of in-gate/orifice （AAAo） and orifice/mould cavity （AolAI）, but the increase trend of up is more intense. The airflow pressure （P1） changes little with Tp and Ao/A1, but increases with the increasing of vp and AJAo. Besides, there is a critical velocity （v ＋｜3YLG cosθ/ppdp｜1/2）for the particles getting into the molten steel. The higher the particle motion velocity, the easier the particles get into the molten steel and the more uniform the distribution of the particles in the steel matrix. When Tp = 1,873 K, vp = 30 mm.s-1, AJAo =10 and Ao/AI = 0.02 in this study, the biggest TiC particle motion velocity （20.59 m.s-~） can be gained, and the steel matrix with the most uniformly distributed TiC particles and fine grains are obtained.

关键词： lost foam-squeeze casting (LFSC) particle motion velocity critical velocity particle distribution

在线全文

学校读者我要写书评

暂无评论

整体式副车架液态模锻及其性能

常州大学学报（自然科学版） 2024年第1期36卷 1-8页

作者：邢书明石洪伟江艳星饶宇北京交通大学机械与电子控制工程学院北京100044 广州和德轻量化成型技术有限公司广东广州210098

液态模锻是铝合金件高性能成型的先进工艺,文章将液态模锻技术用于整体式副车架成型,着重研究液锻工艺方案和液锻副车架性能的均匀性。模拟研究表明,单浇道液锻比设有辅助浇道的液锻汇流位置少、表面质量高、工艺出品率高。试生产发现,... 详细信息

液态模锻是铝合金件高性能成型的先进工艺,文章将液态模锻技术用于整体式副车架成型,着重研究液锻工艺方案和液锻副车架性能的均匀性。模拟研究表明,单浇道液锻比设有辅助浇道的液锻汇流位置少、表面质量高、工艺出品率高。试生产发现,利用广州和德轻量化成型技术有限公司设计制造的HVSC2500T卧式液态模锻机进行A356.2铝合金副车架的单浇道液锻,能够获得完整无缺的副车架,本体取样拉伸强度可达320 MPa,延伸率达11.12%。但是,在远离浇道和存在汇流的位置普遍存在夹渣缺陷,副车架强度和塑性都较低。

关键词：副车架液态模锻力学性能缺陷

Design of process parameters for direct squeeze casting

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2008年第3期15卷 339-343页

作者： Milan Zhang shuming xing Liming Xiao Peiwei Bao Wen Liu Qiao Xin Semisolid Forming Research Center Beijing Jiaotong University Beijing 100044 China Department of Mathematics lli Normal University Yining 835000 China

On the basis of the analysis of solidification interval and temperature distribution of components manufactured by the squeeze casting method, formulas for calculating the solidification interval and compaction pressure were deduced according to the principal request that the compaction pressure should be equal to or greater than the plastic deformation resistance of the forming component when solidification ended. The solidification interval was proven to be associated with many factors, such as weight of the component, specific heat of the alloy, latent heat, pouring temperature, component temperature at the end of solidification and heat-transfer coefficients. The compaction pressure was related to the strain rate, deformation temperature, and dimension of the de- forming component. The solidification interval and compaction pressure calculated by the formulas deduced in this article were adopted in the production of 45 steel bidirectional chapiter valves, and components with excellent oerformance were manufactured.

关键词： squeeze casting solidification time temperature distribution compaction pressure

在线全文

学校读者我要写书评

暂无评论

比压对液态模锻铍青铜件组织和性能的影响

精密成形工程 2024年第4期16卷 165-171页

作者：邢书明高文静鲍培玮闫光远韩亮杨景华高颖北京交通大学机械与电子控制工程学院北京100044 河北省安全工具产业技术研究院河北沧州062150 河北中泊防爆工具集团有限公司河北沧州062150

目的针对先铸坯再模锻方法工艺流程长、能耗高、成本高的缺点,将液态模锻工艺应用于铍青铜件的成形制造中,以提高零件的成形质量、降低成本和能耗。方法在工业生产条件下,对比研究了主要工艺参数比压对液态模锻铍青铜件试样拉伸性能、... 详细信息

目的针对先铸坯再模锻方法工艺流程长、能耗高、成本高的缺点,将液态模锻工艺应用于铍青铜件的成形制造中,以提高零件的成形质量、降低成本和能耗。方法在工业生产条件下,对比研究了主要工艺参数比压对液态模锻铍青铜件试样拉伸性能、冲击性能、硬度及晶粒特征的影响规律。结果当液锻比压从40 MPa提高至80 MPa时,液锻铍青铜的晶粒尺寸可以细化至65μm以下,抗拉强度提高了150 MPa,伸长率由20%提高至40%,硬度和冲击韧性分别提高了35HBW和20 J/cm^(2)。结论液锻比压是影响铍青铜液锻件组织和性能的关键因素,随着液锻比压的增大,液锻铍青铜件晶粒被显著细化,强度、塑性、硬度和冲击韧性均得到显著提高。

关键词：铍青铜液态模锻比压显微组织力学性能

维普期刊数据库博看期刊

在线全文

学校读者我要写书评

暂无评论

复杂内腔铝合金件液态模锻试验研究

精密成形工程 2024年第7期16卷 224-232页

作者：石洪伟陈烨煜杨卫谢德强陈楚明杨家洲邢书明广州和德轻量化成形技术有限公司广州511300 北京交通大学机械与电子控制工程学院北京100044

目的为拓宽液态模锻技术的应用范围,实现具有复杂内腔结构件的高性能短流程成形制造,开展了使用砂芯的液态模锻技术试验研究。方法以具有复杂内腔的新能源汽车铝合金空气弹簧顶座为对象,利用广州和德装备制造公司生产的卧式液态模锻机,... 详细信息

目的为拓宽液态模锻技术的应用范围,实现具有复杂内腔结构件的高性能短流程成形制造,开展了使用砂芯的液态模锻技术试验研究。方法以具有复杂内腔的新能源汽车铝合金空气弹簧顶座为对象,利用广州和德装备制造公司生产的卧式液态模锻机,对比研究不同砂芯、涂料及液锻加压制度对黏砂缺陷的影响作用。结果普通砂芯在液锻中容易被压溃或产生黏砂缺陷;在苏铸砂芯的基础上自行配制HDSC01液锻砂芯,配合HDCoating03专用涂料,采用阶梯加压方法进行液态模锻,所得液锻件内表面光洁无黏砂、尺寸精确。结论液态模锻可以使用砂芯进行复杂内腔结构件的高性能精密成形,但工艺控制不当,容易出现黏砂缺陷。阶梯加压、使用专用砂芯和专用涂料是防止黏砂的有效途径。

关键词：液态模锻加压制度砂芯涂料黏砂

A New Analytical Model for the Flow Stress of Twin-roll Casting Magnesium Sheet at Elevated Temperatures

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第5期26卷 461-466页

作者： Zhimin Liu,shuming xing ,Peiwei Bao,Nan Li,Shuqing Yao and Milan Zhang School of Mechanical,Electronic and Control Engineering,Beijing Jiaotong University,Beijing 100044,China School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing 100044 China

To evaluate the flow stress of the twin-roll casting magnesium sheet in high temperature forming processes,a new analytical model was proposed by analyzing stress-strain curves measured under various temperatures and strain *** model can be parameterized to reflect the volume fraction of semi-sold grain and sold grains undergoing *** applying the new model,the result showed that the simulated stress-strain curves fit the experiment data very *** curve fitting can be employed for any magnesium sheet when the deformation conditions are *** evolution indicated that it affected the stress-strain curves *** mechanisms of dynamic recrystallization（DRX） depended on the operating deformation mechanisms,which changed with *** the volume fraction and grain size of DRX changed with the Zener-Hollomon parameter and temperatures.

关键词： Twin-roll casting Semi-sold grains Twinning

在线全文

学校读者我要写书评

暂无评论

Al-Si合金变质元素及其交互作用

材料导报 2018年第11期32卷 1870-1877页

作者：张佳虹邢书明北京交通大学机械与电子控制工程学院北京100044

铸造Al-Si合金具有轻量化、流动性好、气密性好、收缩率小和热膨胀系数低等优点,已成为铸造业中最受重视的结构材料之一。铸造Al-Si合金的力学性能主要取决于组织中的α-Al相、共晶硅、初生硅、金属间化合物、缺陷以及它们的形态、尺寸... 详细信息

铸造Al-Si合金具有轻量化、流动性好、气密性好、收缩率小和热膨胀系数低等优点,已成为铸造业中最受重视的结构材料之一。铸造Al-Si合金的力学性能主要取决于组织中的α-Al相、共晶硅、初生硅、金属间化合物、缺陷以及它们的形态、尺寸和分布,其中硅相和富Fe相的形貌、尺寸及分布对合金性能的影响尤为显著。未变质的Al-Si合金中针片状共晶硅和针状β-Fe相严重割裂基体,粗大块状初生硅和针片状共晶硅尖端和棱角部位产生应力集中,导致合金的性能尤其是塑性、强度和耐磨性显著降低。此外,硬脆的粗大初生硅还会加快机加工刀具的磨损,加工后零部件的表面光洁度也较差,无法满足实际生产的需要。快速凝固、电磁搅拌、超声处理、机械振动等特殊工艺技术虽然可以在一定程度上改善铸造铝硅合金的微观组织和性能,但是都需要专门的设备和特殊的条件,使其应用受到限制。变质处理不需要任何特殊设备,只需添加少量变质元素,就可以实现对其中α-Al相、共晶硅、富Fe相、细化初生硅等的有效调控,具有成本低、方法简单、效果显著等特点,已成为改善Al-Si合金组织、提高性能最有效的途径。然而,各变质元素的变质机理及它们之间的交互作用极其复杂,如何充分发挥各变质元素及它们之间积极的交互作用是当前的研究热点。近年来对单一变质元素的变质作用机理和效果的研究进展迅速,先后发现了Na、Sr、Sb、P、Ti、Mn和RE等都对铸造铝硅合金有一定的变质作用,并且对它们的变质时效性以及经济性都有了充分的认识。与此同时,也有许多研究者开始关注多元素的交互变质作用并在Sr-X、P-X、Mn-X、Ti-X等二元交互变质方面取得了重要的成果,使变质技术更加经济、有效和灵活。本文综述了铸造Al-Si合金常用单一变质元素的特点、变质作用机理和局限性,系统归纳了Sr、P、Ti、Mn和RE与其他元素间的交互作用规律,筛选出具有协同变质作用的二元/多元变质元素交互作用对,以期为深入探究二元/多元变质元素交互作用的机理,开发更高效、多样、绿色的复合变质剂及变质处理方法提供参考。

关键词： Al-Si合金变质元素交互作用