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Deformation of casting during the solidification process has puzzled many engineers and scientists for years. In order to attain the goal of near-net forming by casting, numerical simulation is a powerful tool. Traditional methods compute the thermal stress of both the casting and the mold. This method suffers the problem of massive calculation and failure of convergence. This paper proposes an improved Mold Surface Element Method, the main idea of which is to use the surface elements instead of body elements to express the interactions between the casting and the mold. The proposed method shows a high computation efficiency and provides satisfactory precision for engineering. Two practical casting products were used to verify the proposed method. The simulated results agree well with those observed in practical products. The proposed method is believed to benefit production practice and to provide theoretical guidance. 相似文献
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An integration system was developed to satisfy the need of information integration in the process of designing, investment casting and monitoring aero-engine's turbo blade. The general architecture is detailed presented in this paper. The system mainly comprises of product master model, design information management, anti-deformation design of mould cavity, intelligence mould design and blade testing. The developed system can manage mould design and blade test data flow, optimize mould design process and achieve the goal of integration design. 相似文献
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Turbine blade is one of the critical components of aircraft engine. The performance of the engine depends on the shape and dimensions of components, but superalloy blade material cannot be easily machined.Although investment casting is an ideal process for such net-shape components, it requires an accurate determination of the casting-die profile. In this paper, a reversing design methodology for investment casting die using ProCAST is proposed. By combining the methods of simplifying grid files and quick sorting, the efficiency of sorting and matching can be largely improved. Further, the mould/die cavity anti-deformation system can be easily built. With ProCAST, the optimized die profile for investment casting can be established. 相似文献
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精铸涡轮叶片蜡模模具型面优化设计方法 总被引:1,自引:0,他引:1
提出一种基于有限元法的精铸涡轮叶片蜡模模具型腔优化设计方法。首先,计算出涡轮叶片在凝固和冷却过程中的非均匀、非线性收缩变形量;然后,基于本文提出的位移场反向迭代算法,确定优化的蜡模模具型腔。以A356合金涡轮叶片为例,采用提出的涡轮叶片模具型腔优化设计系统,经过精度评估,尺寸误差得到了大幅度降低。数值模拟与实验结果吻合良好,经过4次迭代优化,涡轮叶片的总体形状误差从0.515815mm降低至0.001978mm。 相似文献
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高拉速连铸具有高效、低成本的特点,是未来连铸的发展方向。以常规板坯结晶器为研究对象,采用大涡模拟方法对结晶器内的卷渣现象深入分析。结果表明,在连铸坯拉速较低的情况下,结晶器流场较为稳定,钢液冲击速度较小,上返流速度较小,界面波动幅度不大。在高拉速的情况下,钢液冲击速度增加,渣金界面速度及卷渣数量明显提高。通过界面最大速度分析,建立了一个临界卷渣速度的计算准则,发现不同拉速情况下的临界卷渣速度是不一样的,造成这种现象的原因在于卷渣机理的不同。本模型对控制常规板坯高拉速连铸生产具有一定指导意义。 相似文献
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《中国铸造》2016,(5):327-334
A three-dimensional finite-element model has been established to investigate the thermal behavior of the medium-thick slab copper casting mold with different cooling water slot designs. The mold wall temperatures measured using thermocouples buried in different positions of the mold with the original designed cooling system were analyzed to determine the corresponding heat flux profile. This profile was then used for simulation to predict the temperature distribution and the thermal stress distribution of the molds. The predicted temperatures during operation matched the plant measurements. The results showed that the maximum temperature, about 635 K in the wide hot surface, was found about 60 mm below the meniscus and 226 mm from the center of the mold. For the mold with the type I modified design, there was an insignificant decrease in temperature of about 5 K, and for the mold with the type II modified design, the maximum temperature was decreased by about 15 K and the temperature of the hot surface was distributed more uniformly along the length of the mold. The corresponding maximum thermal stress at the hot surface of the mold was reduced from 408 MPa to 386 MPa with the type II modified design. The results indicated that the modified design II is beneficial to the increase of mold life and the quality of casting slabs. 相似文献
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针对某燃机叶片叶型部分形状复杂和轮廓度精度要求高的特点,提出了一种基于熔融沉积技术的燃机叶片快速熔模铸造方法,通过基于NURBS曲线的分层截面生成算法对燃机叶片STL(stereolithography)模型进行分层,提高燃机叶片模样的轮廓度精度,制订了燃机叶片快速熔模铸造工艺流程,采用三坐标测量机对燃机叶片铸件进行测量,对其两个关键截面进行型线轮廓度偏差分析与评价,结果表明:基于熔融沉积技术的快速熔模铸造燃机叶片铸件在轮廓精度方面满足要求,快速熔模铸造工艺流程合理、可行。 相似文献
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The aim of this paper was to study the reaction between a Ti-6Al-4V alloy and boron nitride based investment shell molds used for invest- ment casting titanium. In BN based investment shell molds, the face coatings are made of pretreated hexagonal boron nitride (hBN) with a few yttria (Y2O3) and colloidal yttria as binder. The Ti-6Al-4V alloy was melted in a controlled atmosphere induction furnace with a segment water-cooled copper crucible. The cross-section of reaction interface between Ti alloys and shell mold was investigated by electron probe micro-analyzer (EPMA) and microhardness tester. The results show that the reaction is not serious, the thickness of the reacting layer is about 30-50 μm, and the thickness of α-case is about 180-200 μm. Moreover the α-case formation mechanism was also discussed. 相似文献
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Microstructure of Zn-Al4 alloy microcastings by micro precision casting based on metal mold 总被引:1,自引:0,他引:1
Metal mold micron scale precision casting technology was developed successfully, and three-dimension complicated microgear castings in micron scale were produced. Evolvement regularity of microgear castings were observed by optical microscope and scanning electron microscope. Compared with conventional casting, microcasting is characterized by typical nonequilibrium solidification, for example, its grain size can be refined significantly, eutectic structure is transformed from lamellar morphology to rod eutectic, and the ratio of primary phase is increased. This kind of microstructure can promote mechanical properties of microcasting. 相似文献
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模具电火花电极的智能化设计 总被引:1,自引:0,他引:1
随着塑料制品日趋精密化和复杂化,模具需要电火花加工的部分越来越多,电极设计的工作量很大。因此有必要进行电极设计的自动化和智能化技术的研究。介绍了电极自动设计中需电火花加工区域的自动识别和复杂形状电极的拆解等关键算法。并给出了电火花电极智能设计系统的框架。该系统的运行表明,一个智能化的电极设计系统可以有效地提高电极设计效率。 相似文献
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A turbine blade is one of the key components of the aero-engine.Its geometric shape should be inspected carefully in the production stage to ensure that it meets the tolerance specification.In the present paper,an approach for investment turbine blade geometric shape analysis based on multi-source digital measurement is presented.Its key technologies,such as measurement data collection,blade model reliable alignment,geometric shape deviation fast calculation and visualization,were investigated.Actual measurement data from a structure light measurement device and a Coordinate Measuring Machine (CMM) for turbine blades were used to validate the presented method.The experimental results show that the proposed method is accurate,quick and effective to implement. 相似文献
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模具结构辅助设计Case智能推理系统 总被引:5,自引:0,他引:5
基于事例的推理技术CBR是人工智能技术发展的重要领域之一,而大形事例库的检索,一般的索引法和最近邻主以达到快速、准确的检索要求,因此,有必要研究智能检索推理技术。本文根据事例学习的决策树ID3和PID算法,提出了多概念学习决策树MNID算法,开发了基于事例学习的智能模具相似结构推理系统,燕应用于冲模凸模结构Case库的检索,效果很好,系统通过事例的自主学习,产生出推理规则,并能根据用户对所设计模具 相似文献
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通过一个铝-硅合金端盖压铸件设计实例,探讨了铝-硅合金砂型铸件改为压铸生产时,要在合金化学成分、熔炼工艺和铸件的工艺性能等方面,根据压铸工艺的特点对铸件整个生产工艺进行改进,以满足压铸生产的特殊要求。压铸铝-硅合金中ω(Fe)可以达到1.0%。ω(Fe)〈0.150%时,ω(Mn)要达到0.5%-0.8%,以防止粘模。对于不太重要的铝合金压铸件可以省略熔炼过程中的变质处理过程,通过合理设置加强筋、减少壁厚、减小拔模斜度等措施,改善压铸件的结构工艺性。 相似文献