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以金属凝固理论为基础,I-DEAS和CASTsoft_CAE软件为平台,建立排气管凝固过程的三维模型,对排气管凝固过程的温度场进行数值模拟,温度最大值出现在排气管接口处,最低温度出现在排气管底部;应用新山判据对铸件可能出现缩孔、缩松等铸造缺陷的位置进行预测,预测结果说明缺陷出现在排气管接口处. 相似文献
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复杂薄壁框类铝合金铸件工艺设计及数值模拟 总被引:1,自引:0,他引:1
介绍了一种复杂薄壁框类铝合金铸件的铸造工艺:采用三箱造型,设计了所需砂芯结构,并对中箱造型工艺进行了简化。设计了圆形底注式浇注系统,借助ProCAST软件研究铸件充型和凝固过程。根据初始方案模拟得到缩孔、缩松位置分布和大小,通过在预测的缺陷处合理放置冒口、保温套和冷铁等对铸件进行有效补缩,基本消除了缩孔、缩松等铸造缺陷。 相似文献
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大型导向叶片铸钢件的数值模拟与工艺优化 总被引:1,自引:0,他引:1
利用三维绘图软件Pro/E对大型导向叶片铸钢件做实体造型,应用数值模拟软件View Cast对铸件完成铸造过程温度场的数值模拟,预测铸件产生缩松、缩孔的部位和形成原因.根据模拟结果初步设计了导向叶片的补缩系统工艺方案,对设计的工艺方案进一步模拟优化,最终获得了合理的补缩系统工艺方案. 相似文献
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介绍清华大学开发的计算机三维数值凝固模拟软件FT—Star的功能及其在二重集团公司的工艺性试验和应用研究。解决了软件实际应用于铸钢件凝固过程中出现的一些问题,摸索出一些计算经验和规律。对不同铸钢件如何恰当地剖分网格、确定缩孔缩松判据参数、优化补贴工艺设计等都进行了深入研究,保证了计算机数值模拟结果的精确、可靠。实现了铸造缩孔缩松缺陷的预测,避免过去靠经验来进行铸造工艺设计,使工艺设计更具有科学性,大大降低了铸造生产成本。 相似文献
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《Intermetallics》2015
Gravity and centrifugal investment casting processes of low-pressure turbine blades with high Nb–TiAl alloy were simulated by Procast software. Actual blade components were poured by vacuum induction suspended furnace with Ar protection. The experimental verification indicated that the simulation results were in good agreement with the experimental results. Comparative results had shown that the surface of centrifugal casting blade was more complete than that of gravity casting one. In gravity casting process, molten metal filled the thinnest trailing edge at last, resulting in the generation of misrun defects. Furthermore, the shrinkage porosity and crack defects of gravity casting were much more and dispersive. The internal and external quality of centrifugal casting was much better than that of gravity casting. Microstructures from edge to center of gravity casting blade had no significant change. The microstructure for centrifugal casting blade is finer than that for gravity casting blade, however, a large number of dentritic γ segregation appeared in the blade edge of centrifugal casting, which resulted from the fast cooling rate of centrifugal casting surface. 相似文献
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利用金相和扫描电镜观察了液态金属冷却技术(LMC)制备的DSM11合金重型燃机叶片不同位置的定向凝固组织和热处理组织,并利用持久试验机测试了相应状态下980℃×220 MPa的持久性能。研究表明,随着叶片取样位置远离冷却盘,缩孔的尺寸增加,η相的析出倾向增大,γ+γ′共晶尺寸增加,导致了叶片不同位置热处理组织和持久性能的差异。 相似文献
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利用MAGMA凝固模拟软件预测垂直造型线铸件热节部位和缩松缺陷,模拟结果表明凝固后期形成的孤立热节是产生缩松的主要原因.采用顺序凝固原则可以解决部分缩松问题,但不能解决所有补缩问题.通过优化铸造工艺,改变内浇口位置并重新模拟,发现孤立热节得到了消除,试验结果与模拟吻合,缩松问题得到了彻底解决,利用凝固模拟优化冒口成功提... 相似文献
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重型燃气轮机叶片熔模铸造过程数值模拟 总被引:2,自引:1,他引:1
随着重型燃气轮机的日益发展,对于叶片的热强性提出了极为苛刻的要求。重燃叶片形状复杂且厚大,叶身部位为复杂内腔的薄壁结构,极易出现缩孔、缩松缺陷。为了研究缺陷形成规律,改进其工艺方案,基于有限元法,对充型、凝固过程中的流场、温度场演变及缩孔、缩松形成过程进行了仿真。计算结果显示,原有工艺充型过程中液流有可能在叶盆中部汇合,容易在此处形成卷气。由于榫头上部内浇道较薄,先凝固,造成从冒口向榫头下部的补缩通道阻塞,两种浇注系统均在榫头部位出现缩孔或缩松。对相应工艺进行了实际浇注,试验得到的缩孔、卷气情况与模拟结果吻合。为避免缺陷,应改进原来的浇注系统,在合适的位置设计较大的内浇道。 相似文献
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Formation mechanism of shrinkage and large inclusions of a 70t 12Cr2Mo1 heavy steel ingot简 总被引:1,自引:0,他引:1
Shrinkage cavities and large inclusions are serious internal defects of heavy steel ingot and influence the quality of subsequent forgings.In order to remove these two types of defects,a 70 t 12Cr2Mo1 heavy ingot fabricated by vacuum carbon de-oxidation process was sectioned and investigated by means of structure observation and EDS analysis.To further study the forming mechanism of shrinkage and inclusion defects and find possible solutions,simulation on pouring and solidification processes was also carried out using Fluent and ProCAST software,respectively.Results show that the shrinkage defects do not appear in the middle-upper part of the ingot.The critical value of shrinkage cavity criterion is ascertained as 0.013 on the basis of sectioning investigation and simulation results,which can be used in computer simulation to predict and avoid shrinkage defects in production of 12Cr2Mo1 ingots with different weights.However,large inclusions are found at the bottom of the ingot body.The bad thermal conditions of the ingot surface and large amount of entrained slag are the main origin of the large inclusions.The simulation result of the pouring process shows that large inclusions may be eliminated by combined measures of improving the top thermal condition and controlling the height of rudimental molten steel in the ladle to above 300 mm. 相似文献
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景艳红 《稀有金属材料与工程》2017,46(2):317-321
采用不同的射线设备对注射成形的MIM418涡轮进行检测,并对缺陷进行了解剖,采用光学显微镜OM和扫描电镜SEM观察其形貌,和EDS确定其成分,采用MIM TAB 软件对涡轮不同部位的缺陷进行了统计分析,并研究了热等静压(HIP)对缺陷的影响。研究结果表明:胶片x射线设备比实时呈像具有更高的检测灵敏度,微焦点射线设备,不适用于MIM418涡轮得检测,X射线检测和缺陷形貌观察表明在涡轮心部易于形成裂纹,相比较心部,在叶片处的气孔型缺陷更多一些,采用HIP可大幅度降低气孔型缺陷,但裂纹并不能愈合。 相似文献
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