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A new shell casting process based on expendable pattern with vacuum and low-pressure casting for aluminum and magnesium alloys 总被引:1,自引:1,他引:0
Wenming Jiang Zitian Fan Defeng Liao Xuanpu Dong Zhong Zhao 《The International Journal of Advanced Manufacturing Technology》2010,51(1-4):25-34
A new shell casting process, with the adoption of the foam pattern of lost foam casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment casting and vacuum and low-pressure casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and low-pressure casting process. The few-layer compound thin shell of silica sol–sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250°C for 30 min, and the shell was roasted at 800°C for 1 h. Combined with the vacuum and low-pressure casting process, this new shell casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell casting, gravity casting, and LFC were also made to show the characterization of this new shell casting process. 相似文献
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Wenming Jiang Zitian Fan Dejun Liu Hebao Wu 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2459-2468
In this study, a new casing process named expendable pattern shell casting process with vacuum and low pressure (EPSC-VL) was introduced to produce complicated and thin-walled aluminum alloy castings. The gas flowrate is one of the most important process parameters for manufacturing castings during the EPSC-VL process. In the present work, the influence of gas flowrate on the filling ability and internal quality of A356 aluminum alloy castings fabricated by the EPSC-VL process were investigated. Moreover, the filling ability, internal quality, as well as mechanical properties of A356 aluminum alloy castings obtained by EPSC-VL and lost foam casting (LFC) processes were also compared. The results obtained suggested that the filling length increased with the increase of gas flowrate, and the filling length of the thick section was larger than that of the thin section under the same gas flowrate when the gas flowrate was less than 19 m3/h. Furthermore, the porosity of castings decreased with increasing gas flowrate, and the microstructure of castings became denser, and the internal quality of castings was obviously improved. The comparison experiments showed that the EPSC-VL process had superior filling ability, internal quality, and mechanical properties compared with the LFC process, and the surface quality of castings obtained by EPSC-VL process was also better than that of the LFC process. The casting practice of complicated and thin-walled A356 aluminum alloy intake manifold part also suggested that the EPSC-VL process had an obvious advantage for the fabrication of complicated and thin-walled aluminum alloy castings compared with the LFC process. 相似文献
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消失模铸造技术是一种利用泡沫模样代替传统复杂造型过程实现零件生产的铸造工艺。近二十年来,消失模铸造广泛应用于具有复杂结构零件的铸造,通常情况,铸件越复杂越能体现该工艺的优越性。20世纪90年代,美国成功地将消失模铸造技术应用于发动机缸体缸盖的工业化生产,使得零件设计更为柔性、集成度高,减轻铸件重量,提高燃油效率,降低成本;目前我国企业尝试用消失模铸造技术小批量生产缸体缸盖,初步获得成功,开始走向市场,但由于受到增碳、气孔等铸造缺陷的困扰,还未能实现低废品率的大批量工业化生产。 相似文献
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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。 相似文献
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采用有限元法建立了铸件凝固过程的数学模型,考虑材料随温度变化的非线性因素和相变中结晶潜热问题,对铸造凝固过程进行了数值模拟,得到了铸件在凝固过程的瞬态温度场、温度梯度场的分布和变化规律。预测出了铸件可能出现缩孔、缩松等铸造缺陷的位置,结果表明模拟预测与生产验证结果基本一致。 相似文献
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叙述铸钢件工艺CAD的基本方法,在工艺校核方法上成功引入铸件凝固三维数值模拟技术,得到设计结果与实际情况相符的效果。 相似文献
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介绍了低压铸造工艺的生产流程、工艺设计要点,结合装载机变矩器铸铝件泵轮热节分布分散的结构特点,论述泵轮的低压铸造工艺的设计要点和关键的工艺过程参数温度场、充型速度、充型压力3个方面的控制技术。 相似文献
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STUDY ON NUMERICAL SIMULATION OF MOLD-FILLING AND SOLIDIFICATION PROCESSES OF SHAPED CASTING 总被引:5,自引:0,他引:5
Xiong Shoumei Liu Baicheng Department of Mechanical Engineering Qinghua University 《机械工程学报(英文版)》1999,12(1)
0INTRODUCTIONInrecentyears,considerabledevelopmentshavetakenplaceinthefieldofCADandsolidificationmodelingofcastingprocess[1~... 相似文献
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为了解决6061铝合金熔点与现有货架产品Al-Si-Cu-Mg系钎料熔点较为接近、钎焊工艺难以控制的难题,开展了Al-Si-Cu-Mg系钎料钎焊6061铝合金的工艺研究.通过合理的焊接工艺参数试验设计,得出了合适的6061真空钎焊焊接工艺参数.对钎焊样件进行组织性能分析及耐腐蚀性试验,发现在合适的钎焊工艺参数控制下,钎焊接头中的Cu在焊缝区域产生了扩散,只有极少量的Cu与Al形成了共晶组织.中性盐雾试验结果表明,钎焊缝中极少量的Al-Cu共晶组织对其抗腐蚀性影响不大. 相似文献
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铸件凝固过程数值模拟影响因素研究 总被引:1,自引:0,他引:1
对铸件凝固过程数值模拟影响因素及流程进行了研究。并采用华铸和ProCAST软件分别对轴承盖铸件凝固过程进行了分析及软件应用比较。根据凝固模拟的结果及铸造缺陷情况及其与实际浇铸的情况对比,得出了相应的铸型瞬时充满简化假设条件的有效性等结论。 相似文献
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利用SolidWorks三维造型软件,运用华铸CAE铸造凝固模拟软件对汽轮机阀体铸钢件充型、凝固过程进行模拟分析.通过对凝固过程的数值分析,结合生产中的实际经验,找出原有生产工艺中缺陷的形成原因.针对缺陷的形成原因,设计出相应的修改工艺,保证了铸件的质量,降低了生产成本和生产周期,满足客户的需求. 相似文献
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对精加工表面磁粉探伤后出现大量微细磁痕的铸钢大链轮的原铸造工艺进行了凝固数值模拟分析 ,认为缺陷是由于顺序凝固方向上温度梯度过于平缓所致的微小缩松 ,对缺陷部位进行纵横截面的切片金相分析印证了模拟分析是正确的。据此 ,本着增大凝固方向上的温度梯度的原则用数值模拟技术进行了 15种方案的工艺优化计算并结合现场生产确定了优化方案 ,实际浇注结果表明 ,方案是成功的。用同样的原理和方法对系列轴承座的铸造工艺进行了优化并在实际中获得了成功。进一步讨论说明 ,要获得致密的铸钢基体 ,在铸造工艺设计中应注意使凝固方向上的温度梯度足够大以使液 -固界面的推进方式向逐层凝固的方式靠近。 相似文献
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Jiehua LI Bernd OBERDORFER Daniel HABE Peter SCHUMACHER 《Frontiers of Mechanical Engineering》2018,13(1):48-52
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. 相似文献