共查询到20条相似文献,搜索用时 421 毫秒
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齿轮厚实的轮载、轮缘由薄壁辐板连接构成,这样的结构,给铸造造成轮毂和轮线两个热节区。通常在一般的手工砂型铸造条件下,很容易出现轮缘和轮毂热节区的缩孔和缩松缺陷。为保证齿轮铸件的产品质量,1991年我们对承接的球铁齿轮铸件选择了从轮毂进水、轮缘设成形冷铁的手工砂型铸造生产工艺,铸造工艺示意图见图。按上述工艺投入生产后,多数品种的齿轮铸件的成品率在93%左右;但有一些品种齿轮铸件的成品率仅为50%左右,废品的主要原因为轮缘区的缩孔和缩松缺陷。为什么采用相同的铸造工艺会出现如此大的差别?根据铸造工艺可看出:齿… 相似文献
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为使企业能够稳定生产高质量的铸铁轮类件,采用统计的方法研究冷铁在铸铁轮类件铸造工艺中的应用,统计了冷铁在铸铁轮类件的安放位置、使用数量以及冷铁尺寸等,提出了轮类件冷铁使用条件、设计计算方法及使用准则.优先要把外冷铁放在轮缘外侧和下侧,对于轮形铸件,应限制冷铁使用次数,如齿轮类铸件为10~15次. 相似文献
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大型球铁齿轮无冒口铸造工艺 总被引:1,自引:1,他引:0
0引言从动齿轮是我厂各种抽油机减速器主要零件之一。材质为QT700-2;铸件最大尺寸为中1040×345mm,主要壁厚70mm,总重1057kg;技术要求:球化率不低于4级,球径不低于5级,热处理后硬度值210-260HB;铸件无缩孔、缩松等铸造缺陷。1工艺方案的比较图1为采用组合冷铁冒口型生产的CYJ10C-53K减速器从动齿轮的铸造工艺。本方案是按定向凝固的原则设计的,轮缘处放置外冷铁,而把冒口放在轮毂上方,铁液由雨淋浇道经冒口-轮毂-轮幅到达轮缘。可获得无编松、缩孔的合格铸件。但是重100… 相似文献
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近几年我厂通过对大型中、高碳钢和合金钢轮型件工艺操作的综合分析和生产实践,总结出以下几项工艺措施、杜绝了铸件废品。下面以实例说明我们的作法。一、关于大型轮件的材质与结构齿轮件多采用低锰合金钢,一般有 相似文献
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介绍了铸钢齿轮的三种工艺:水平浇注对工装要求低,铸件工艺出品率低,而且用于大平面的铸钢齿轮极易产生夹砂等缺陷;倾斜浇注可使铸件工艺出品率提高8~15%,改善了铸件的表面和内在质量;平做立浇对工装要求高,适用于大批量生产的中小型铸钢齿轮,可提高作业面积利用率。 相似文献
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轮类件的典型浇注系统 总被引:2,自引:2,他引:0
皮带轮、飞轮、齿轮、蜗轮等轮类铸件产过程中,工艺不合理或操作不当,会产生气孔、夹渣、裂纹、疏松等缺陷,因此,选择正确的工艺方案,采用合理的浇注系统是十分必要的. 相似文献
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介绍了轧机减速器大型齿轮的生产,通过合理的选材、改进齿轮的结构、优化铸造工艺参数,采取必要的防裂措施等,生产出合格的大型齿轮铸件。 相似文献
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带轮真空压铸模设计与制造 总被引:2,自引:1,他引:1
带轮采用真空压铸工艺,提高了带轮铸件表面质量;模具的双抽芯机构减小了单方向抽芯力,解决了铸件变形问题。在分析了带轮零件压铸工艺性的基础上,论述了模具的设计要点和工作原理,给出了工艺参数和实用的模具结构,改进了模具制造工艺。 相似文献
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本文研究了铸件和铸型的热物性值对铸钢件凝固过程温度场数值模拟精度的影响,指出铸型的热物性值较铸件的热物性值对模拟计算精度的影响更大。计算时,必须正确掌握不同铸造工艺条件下确切的热物性值。 相似文献
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任何一家球铁铸件生产厂都会发现,利用灰铁铸件的补缩方法,解决不了球铁铸件的缩孔、缩松问题。S.I.Karsay提出的利用球铁的共晶膨胀压力而不是补缩铁水,消除二次收缩过程形成的缩孔类缺陷,目前已经成为工业发达国家中流行最广的一种实用技术体系。 相似文献
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Abstract: The properties of aluminium castings are strongly affected by their inclusion content, particularly entrained surface alumina films. These form due to the surface turbulence associated with mould filling, which causes the oxidised surface of a liquid metal to fold-over onto itself and be submerged into the bulk liquid with a thin layer of air entrapped within it. This is known as entrainment action. These flaws have been reported to increase the variability of the fracture strengths of Al alloy castings. This means that shape castings in light alloys can have inconsistent properties, which makes designing structures employing shape castings more difficult. Entrained surface layers can cause premature failure, but also have been associated with other defects, such as hydrogen porosity, shrinkage porosity, intermetallic compounds and hot tearing. Recent research has suggested that the air inside the defect would react with the surrounding melt leading to its consumption, which may enhance the mechanical properties of the casting. In this work, liquid aluminium was poured into three identical ceramic moulds which were immediately placed in a furnace to preserve the molten metal at 800 °C, for different periods of time prior to freezing. The Weibull moduli of the plate castings were determined under tensile conditions, and their fracture surfaces examined using SEM. Investigation of the fracture surfaces of the specimens detected many alumina layers at different locations. Many of which were found inside pores, reflecting the role of entrained defects in the formation of porosity. The results also suggested that opposite phenomena may take place during the holding treatment. The consumption of air inside the entrained defects due to reaction with the surrounding molten metal may lead to improvements in mechanical properties, but this may be accompanied by hydrogen passing into the defects, which has a deleterious effect on properties. 相似文献
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