镁合金轮毂低压铸造工艺数值模拟

对汽车上镁合金轮毂的低压铸造过程进行了数值模拟，研究了填充和凝固过程中温度场与流场的分布，预测在此过程中可能出现的各种缺陷，结果发现，通过降低浇注速度，可有效地消除在浇铸过程中所产生的气孔和部分缩孔缺陷。对于容易在轮辋与轮辐连接处产生的热节，通过对这些部位的模具冷却性能进行研究，分析了不同冷却方式对热节产生的影响，结果发现，单独设置侧模冷却管道是一种有效的冷却方式，可以使热节减小，并使其位置发生改变。     

压铸件铸造缺陷的计算机模拟与预测研究

压铸件铸造缺陷的分析及预测研究对保证压铸质量具有非常重要的意义。针对复杂、小型、薄壁压铸件的收缩缺陷，综合考虑了压铸件形状及其凝固过程中温度变化对缩孔缩松及气孔发生的影响机理，在其凝固过程温度场数值模拟的基础上提出了一种新的压铸件缩孔缩松判据。应用该判据对压铸件收缩缺陷和气孔缺陷的发生及危险部位进行了模拟预测，并对模拟预测的结果进行了可视化显示。预测结果与压铸件缺陷实际发生情况一致。     

高锰钢前导轮铸造工艺模拟及优化

高锰钢前导轮内腔结构复杂,需要合理的铸造工艺以避免填内部产生铸造缺陷。为此,采用商业软件ProCAST对导轮轴孔处设一个明冒口的单冒口工艺（SR）和两个明冒口的双冒口艺艺（DR）进行缺陷预测、计算发现,单冒口工艺（SR）的缺陷形成倾向低于双冒口的工艺（DR）。进而,通过调整单冒口工艺（SR）的冷铁形状、位置及增大轮缘处暗冒口体积．提出优化工艺M1;在M1基础上,通过减小轴孔处明冒口体积,并加大该处冒口保温砖厚度,提出优化工艺M2,模拟计算表明,采用M1和M2工艺均可消除导轮轮缘处的缩孔缩松缺陷;以M2的热裂倾向最小,热裂纹主要出现在前导轮内腔垂直拐角处和轴孔附近。     

铸造模拟仿真软件在汽车零件铸造工艺设计中的应用

以制动主缸为例,介绍了ProCAST软件在金属型重力铸造工艺中的应用,对制动主缸充型和凝固过程中产生的常见缺陷,进行了预测分析,通过软件的后处理模块,能直观地观测到铸造生产过程中气体包卷、缩孔等缺陷的分布,对铸造缺陷准确的预测,能有利于评价铸造工艺方案、把握铸件品质的影响因素,透彻认识铸造过程,同时有利于为铸造工艺的改进提供正确的方法,避免了多走弯路,节约了试制成本,提高了产品品质。     

YC6108柴油机缸体铸件质量问题与对策

针对 YC6 1 0 8柴油机缸体铸件出现批量气孔、疏松、冷隔、缩孔的现象 ,结合生产过程 ,分析了导致缺陷的原因 ,提出了相应的对策。     

微框架效应磁悬浮飞轮转子轮缘优化设计

基于由磁阻式锥形磁轴承和洛伦兹力磁轴承组成的五自由度微框架磁悬浮飞轮,对转子轮缘进行了优化设计.根据飞轮转子结构特性,提出以质量为优化目标,对轮缘质量、极转动惯量和一阶共振频率等进行理论分析和研究,确定了优化变量.应用优化设计软件iSIGHT集成有限元分析软件ANSYS,采用序列二次规划算法,以一阶共振频率、极转动惯量、最大等效应力、极惯性矩与赤道惯性矩之比等作为约束条件并考虑轮辐根数对轮缘质量的影响,对轮缘进行了优化计算,得到了相关变量的最优化结果.结果表明,其他变量最优、轮辐根数为3时,轮缘具有最小质量为2.036 kg,比初始质量2.226 kg减小了8.54％.提出的优化方法提高了转子设计的合理性和效率,对飞轮系统整体优化设计具有重要意义.     

金属型铝合金重力浇注装置及其模具设计的研究

为适应较小规模铸造企业的生产模式、有效提高铸件质苎．对铝合金重力浇注装置及其模具结构进行设计研究。在装置上采用简单的机械结构使之方便手动操作，使用完全金属型模具并使之具有倾转功能。研究发现在浇注过程中具有操作简单方便、易于维护，并且制造成本低廉、模具设计制造周期短的特点。铝合金液体在模具中的充型和排气效果良好，可减少气孔、缩孔等铸造缺陷。特别适用与中小型企业的小批量铸件的生产和产品零件的试制加工。     

压铸镁合金用热作件材料的进展

分析了镁合金压铸热作件的失效形式及性能要求，并对国内外镁合金压铸热作件材料进行综述，对热作件所用的热作模具钢的发展提出了建议。     

压铸技术与装备的新发展

综述了压铸技术及其发展现状、镁合金及其成形技术、铝锌合金挤压成形技术、计算机在压铸领域中的应用、压铸新装备。     

6t锭补注工艺优化

自从6 t锭投产以来,其钢锭锭身上部尤其是帽口线处的缩孔和锭身的中心疏松一直是困扰该种锭型的主要质量问题。钢锭上部缩孔和中心疏松的形成与补注有直接关系,现行工艺的执行,虽然在一定程度上减轻了上属质量问题,但结果不令人满意。本次工艺试验的主要目的是通过对6 t锭浇注的过热度和补注时间进行分段试验,以得出在不同过热度下的最佳补注时间和浇注该种锭型的最佳过热度,从而实现6 t锭补注工艺的优化。     

Automotive wheel with cooling fan for brake system and in-wheel motor

For suppressing the automotive troubles like an overheating of the drum/disc brake units or the in-wheel motor devices, authors propose the new automotive wheel with the blade shape spokes, which can work as the cooling fan, by use of the blade design procedure of the turbomachinery. In this paper, the prototype automotive wheels with the centrifugal or axial type blades were prepared to confirm the flow generation by proposed wheels experimentally and numerically, as the preliminary step. The proposed wheel brings the increase of the air flow through the wheel compared with the traditional wheel, which has the rectangle shape spokes. At a same time, the required power for the rotation wheel rotation with cooling fan also increase about 2–4% of the traditional one. Furthermore, the swirling inlet flow, which generates by the rotating cylindrical rim, may greatly influences the discharge performance of the wheel with the axial blades.     

凝固过程应力场模拟技术在大型铸钢件中的应用

基于FDM／FEM方法，对某水轮机下环铸件的整个铸造过程中的热应力进行了模拟计算。模拟中采用接触单元法处理铸件与砂芯之间力的作用，改进了传统的铸件／铸型边界条件处理方法。根据应力场模拟结果，分别采用不同的判据，对铸件整个凝固、冷却过程中的热裂和冷裂倾向性进行了预测。揭示了铸件从凝固到冷却至室温的变形规律，为控制铸件收缩尺寸提供了参考。实际生产结果与预测结果相吻合。     

压铸技术及压铸合金的发展与应用

简述了压铸发展的历史及压铸技术的发展状况。叙述了压铸铝合金、镁合金、锌和锌铝合金的研究开发与应用状况,分析了压铸合金有待进一步研究开发的问题     

Machining parameters optimization on the die casting process of magnesium alloy using the grey-based fuzzy algorithm

The present investigation focuses on finding the optimal machining parameters’ setting for the die casting process of magnesium alloy using the grey-based fuzzy algorithm. This proposed algorithm, coupling the grey relational analysis with the fuzzy logic, obtains a grey-fuzzy reasoning grade to evaluate the multiple performance characteristics according to the grey relational coefficient of each performance characteristic. One of the real case studies performed in the die casting process, thin-walled cover components of liquid crystal display (LCD) panel, verifies that the proposed optimum procedure is feasible and effective. The casting density, warpage and flow mark of finished product are adopted to evaluate the machiniablity performances. Various die casting parameters, such as the die temperature, the pressure of injection, the plunger velocity (first and second stage) and the filling time are explored in the experiment. The table of orthogonal array is used in the experimental design. The response table, response graph and analysis of variance (ANOVA) are used to find the optimal setting and the influence of machining parameters on the multiple performance characteristics. Under the circumstances of the optimal machining parameters, the confirmation tests indicate the effectiveness of the proposed algorithm. Experimental results have shown that the required performance characteristics in the die casting process have great improvements by using this proposed algorithm.     

镁合金压铸的应用前景之探讨

讨论了国内镁合金压铸的应用现状，发展镁合金压铸的优势与前景，介绍了国内外发达国家和地区镁合金压铸的发展，提出了镁合金压铸仍需解决的问题。     

Thermal analysis of casting dies with local temperature controller

In high pressure die casting processes, a die plays a critical role in removing heat from the molten metal during the cavity filling and solidification stages. Proper control of die temperature is essential for producing superior quality components and yielding high production rates. In this paper, a computerized intelligent real-time monitoring and control system (IRMCS) is developed for die casting processes involving cooling of a die with multiple channels. A local temperature controller is designed to monitor temperature signals from the die insert and flow rate signals from the cooling lines. The performance of the controller is evaluated, and the effect of the controller on local temperature and heat transfer of casting dies is analyzed. The experimental results obtained from a laboratory die casting process simulator indicate that the developed control system is capable of adjusting the desired supply of cooling water into multiple cooling lines, which effectively controls the local temperature of the die insert within a given range. Hence, the desired thermal pattern of the die becomes achievable.     

Determining casting defects in near-net shape casting aluminum parts by computed tomography

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.     

铸铁件常见缺陷产生的原因与防止

主要介绍了铸铁件中常见的几种缺陷,如气孔、渣孔、缩松、硫松、热裂、冷裂产生的原因及防止方法.     

Rapid casting of turbine blades with abnormal film cooling holes using integral ceramic casting molds

Film cooling is an important cooling method to decrease the turbine blade surface temperature, and its average cooling efficiency is mainly dependent on the cooling structures of internal passageways and the shapes of film cooling holes. Compared with standard cylindrical film cooling holes, abnormal film cooling holes have higher average cooling efficiency. But it is difficult to manufacture these holes using traditional machining methods. In this paper, a novel process was developed to fabricate turbine blades with abnormal film cooling holes by combining stereolithography (SL) technology with gelcasting technology. To decrease the drying shrinkage, the freeze-drying technique was applied to treat the wet ceramic casting mold green body surrounded by the SL mold, and the proper sintering process parameters were determined for lowering the sintered shrinkage. Finally, the integral ceramic casting mold was obtained, and a turbine blade with converging–diverging film cooling holes was rapidly cast to verify the feasibility of the proposed process.     

强制风冷在大型铸钢件砂芯上的应用

通过活动横梁铸件简化模型研究了冷铁、自然风冷和强制风冷对厚壁回转体大型铸钢件凝固时间和砂芯温度场的影响。砂芯采用强制风冷铸件凝固时间最短,而采用冷铁不能缩短铸件凝固时间。通过对比不同冷却条件砂芯的温度场发现无强制冷却砂芯和冷铁砂芯分别在13 h和12 h出现热饱和现象,随后砂芯中心到铸件的温度梯度转为负值,砂芯向铸件输送热量;而砂芯采用自然风冷和强制风冷时从砂芯中心到铸件建立了正的温度梯度,能有效吸收铸件凝固期间释放的热量而改善其冷却条件;强制风冷对流换热系数高,冷却作用明显。对活动横梁铸件原始工艺改进,砂芯采用强制风冷;模拟结果与原始工艺相比缩孔位置上移,表明冒口补缩能力增强;同时砂芯实测温度场与模拟温度场相吻合,验证了模拟结果的可行性,由于砂芯在高温热作用下的时间短,经改进工艺所生产的活动横梁铸件中心孔表面无机械粘砂。