共查询到19条相似文献,搜索用时 144 毫秒
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散热器有气密性要求,精铸生产有一定难度。对铸件的结构进行了详尽的分析,从浇注系统设计、充型速度、型壳的浇注温度、钢液过热度等方面分别提出了相应的工艺措施,从而改善了铸件的气密性能,减少焊补,提高铸件成品率。 相似文献
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延三成 《特种铸造及有色合金》2011,31(11):1036-1037
消失模铸造时,为了满足铸件局部特殊性能要求,在铸件模样局部加入合金元素同时加入稀土元素。铸件成形后,合金元素与稀土元素同时溶入了铸件相对应部位。试验证明,铸件局部合金化可以改善消失模铸件的局部特殊性能。 相似文献
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《特种铸造及有色合金》2016,(7)
通过对比热等静压前后合金的拉伸性能、疲劳性能和组织缺陷,研究了热等静压对ZL114A合金铸件组织和性能的影响。结果表明,热等静压可使铸件力学性能提高(抗拉强度提高了4.8%、伸长率提高了144%),经热等静压后,铸件疲劳性能可提高98%,热等静压对铸件中缩松、细小气孔等缺陷能进行有效修复。 相似文献
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采用卧式TRD-800T型挤压铸造机,研究了间接挤压铸造工艺对汽车控制臂铸件组织及性能的影响。结果表明,在一定范围内挤压比压的增大将使铸件力学性能得到提高,但超过140 MPa后,性能改善并不明显。挤压比压较低时,仅有利于铸件宏观缺陷的改善;挤压比压较高时,还可提高合金液凝固速度,明显细化铸件的显微组织。铸件最佳挤压比压为140 MPa,在此条件下,ZL114A合金铸件的平均抗拉强度为354 MPa,伸长率为11%,硬度(HB)为112,铸件内部品质良好,无缩孔、缩松、裂纹、夹渣等冶金缺陷。 相似文献
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对Al-Si-Cu合金进行消失模铸造,研究涂层厚度对Al-Si-Cu合金铸件缺陷、孔隙率和共晶硅间距的影响。结果表明,提高涂层浆料黏度和延长浸渍时间对铸件的完整性和显微组织有影响。薄的涂层有利于模腔充填性能的改善、显微组织的细化和低孔隙度高质量铸件的获得。 相似文献
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可倾转式重力铸造集中了底注和顶注的优点,既有利于金属液充填型腔过程中渣气的排出,也有利于铸件的顺序凝固。汽车空调双管气室是大型薄壁类铸件,有气密性要求,成形困难,易产生浇不足、冷隔等铸造缺陷。利用可倾转重力铸造生产汽车空调双管气室,并通过对浇注系统和工艺参数的优化设计,能大大减少铸件内夹渣和气孔的缺陷,提高铸件机加工后和一次气密检验(无浸渗)的合格率。 相似文献
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抽真空截止点的位置对压铸件气孔的影响 总被引:2,自引:0,他引:2
陈国策 《特种铸造及有色合金》2000,12(2):38-39
在真空压铸中 ,抽真空截止点的确定对压铸件的品质影响很大 ,过早和过迟将影响压铸的连续生产和不利于减少铸件的气孔。抽真空截止点应设在冲头快压射前 15~ 2 0 mm处 ,真空压铸可以提高铸件的密度 1%以上Influence of V 相似文献
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近年来,真空压铸技术在国内外得到了广泛的应用,目前国外高真空压铸的方法主要有3种,分别是来自德国的Vacural法和MFT(MinimumFillTime),以及来自日本的vaccumGolveBox法,国内学者也研制出了各种真空压铸方法。在真空压铸技术领域中,重点要解决是模具密封与真空截止阀的问题,本文总结了目前实际应用中的各种真空压铸方法与工艺,探讨了真空压铸技术在实际运用过程中面临的主要问题,并在此基础上开发设计了具有自主知识产权的锌合金高真空压铸造工艺法。 相似文献
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B. D. Lee U. H. Baek J. W. Han 《Journal of Materials Engineering and Performance》2012,21(9):1893-1903
High-pressure die casting is the preferred process for manufacturing Mg-alloy components used for numerous applications. High-pressure die casting is suitable for mass production and has the advantage of also being suitable for accurately fashioning objects of complicated shapes. One disadvantage of high-speed die casting is the occurrence of defects such as shrinkage or air entrainment. Gating system design must be very effective in actual manufacturing facilities to avoid the occurrence of such defects. The objective of this study is to present a methodology for obtaining optimal designs of 4-cavity thin electronic component housings. The fluid behavior and amount of air entrainment caused by the overflows and air vent designs were analyzed using a computer fluid dynamics (CFD) simulator. The effectiveness of the proposed system was demonstrated through CFD simulations and experiments using an actual manufacturing process. Also, the effect of vacuum systems on the porosity and mechanical properties of the castings was studied. The volume of porosity in the casting was found to be significantly reduced using vacuum assistance during die casting. As a result, the tensile strength and the elongation of the die casting products are improved. 相似文献
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Ying-hui Wei Li-feng Hou Li-jing Yang Bing-she Xu Munehiro Kozuka Hideki Ichinose 《Journal of Materials Processing Technology》2009,209(7):3278-3284
In this paper, microstructures and properties of die casting components with various thicknesses made of AZ91D alloy have been investigated by means of scanning electron microscope (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), etc. It is concluded that mechanical properties of the die casting components mainly depend on grain size of α-Mg phase. At the same time, however, the voids formed by entrapping air during die casting process have a remarkable detrimental effect on the mechanical properties. To what extent the effect is caused is determined by quantity, size and shape of the voids, which are related to the thicknesses and position of the component in die. Nanometer particles found on the wall of the voids are magnesium oxide compounds, which are formed when oxygen from the entrapped air reacts with magnesium during die casting process. The compounds have no obvious effect on the mechanical properties even though there is possibly volume change present to form other compounds in the course of the components’ being used. 相似文献
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真空压铸的发展 总被引:2,自引:3,他引:2
陈金城 《特种铸造及有色合金》1996,(5):32-33
真空系统是压铸过程中排除气体的最有效的方法之一。然而,真空压铸的发展几经起伏,现在则发展到一个新的阶段。从模具中抽出气体是几种抽气方法中较为简便的一种。真空气道的设计与常规气道则有所不同 相似文献
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低压铸造过程铝熔体的氢含量变化 总被引:1,自引:0,他引:1
在不同的压缩空气相对湿度下,试验测定了低压铸造过程中液态铝合金氢含量的变化。结果表明,尽管真空精炼具有很强的除气能力,但低压铸造的除气效果与压缩空气的相对湿度有关。潮湿的空气会造成含氢量的波动,干燥的压缩空气更有助于获得高质量的铝合金液。 相似文献
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Development of vacuum die-casting process 总被引:1,自引:0,他引:1
Masashi Uchida 《中国铸造》2009,6(2):137-144
The vacuum die-casting process, started 25 years ago in Japan, has been widely applied. This technology contributes very much to improvement of castings quality. The main factor causing the defects of die castings is the trapped air in the mold cavity, while the key technology of vacuum die-casting process is to avoid the trapped air effectively by evacuating the cavity before casting. At the same time, due to the shot speed and the casting pressure reduced in half, the service life of the die is prolonged and the productivity is enhanced, as well. Vacuum die-casting process is of great significance in improving the die castings quality and making up the shortcomings of super-high-speed shot casting. 相似文献