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在近20年中,铸造工艺模拟已经从预测热节和凝固过程发展到为铸造厂总体评价铸件的整个生产路线的工具.与铸造方案有关的保证补缩依然是铸造工艺模拟最重要的任务之一.对于所浇注的合金,要提供无缺陷的铸件,需要考虑不同的补缩特性和自补缩能力.因此,仅仅根据由温度场导出的热节来预测收缩缺陷是不够的.为了能定量预测这些缺陷,凝固模拟必须与密度和质量迁移的计算相结合,以求出凝固形态对补缩特性的影响,并应考虑合金相应的补缩范围.对于铸铁厂来说,应用铸造工艺模拟已成为预测所采用工艺的耐久性和可靠性的重要手段,尤其是为了要定量表示铸铁的凝固和收缩特性,必须考虑合金元素、熔化操作和冶金因素的影响.这种模拟不但允许预测铸铁的局部组织、相组成及最终的力学性能,在铸造厂内评估铸件质量,还可在铸件设计过程中使用这种定量信息.目前的技术发展水平已允许定量预测铸铁件的残余应力和铸造变形,还可确定铸件中的裂纹以及在热处理过程中铸造应力的降低.文中将概述目前定量预测铸铁件特有缺陷和铸件性能方面的能力,并重点介绍在模拟铸铁件制造和ADI以及预测铸铁件应力方面的最新发展. 相似文献
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用JSCAST铸造模拟软件,对常用牌号铸铁件的应力框模拟试样进行铸造变形解析,对其内部应力及变形进行预测和对比分析.用树脂砂铸造工艺浇注QT600-3应力框铸件,以测量实际应力和变形,验证模拟结果,并提出减小铸铁件应力及变形的措施.结果表明,铸件的实际应力及变形与模拟结果基本一致;球墨铸铁的残余应力明显高于灰铸铁,且强度越高,应力越大,密烘铸铁的应力及变形状态与球墨铸铁相似,高弹性模量有利于保证铸铁件质量.建议从选择优质铸造合金材料、改善铸件结构、优化铸造工艺和提高组织均匀性等方面减小铸铁件的残余应力. 相似文献
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本文运用铸铁件“均衡凝固与有限补缩理论”,对孕育铸铁的收缩特性和具体铸件的补缩特点作了分析。提出该类合金无冒口铸造工艺设计的方法,为铸铁件铸造工艺方案的制定开辟了新路。 相似文献
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绞车滚筒铸铁件的铸造工艺设计和数值模拟 总被引:4,自引:4,他引:0
对铸铁件JH-20型回柱绞车滚筒进行铸造工艺设计.根据铸件形状对称的特点,设计了底注式浇注系统,采用两个内浇道同时对铸件浇注.利用CAD软件建立铸件的三维模型,并用ViewCast铸造模拟软件对铸件的凝同过程进行了数值模拟.模拟显示,在滚筒与法兰连接处会产生缩孔、缩松缺陷.根据数值模拟结果并结合理论分析,对铸造工艺方案进行工艺改进.通过增设冒口的方法,利用冒口对铸件进行补缩,以实现铸件的顺序凝固.结果表明,优化后的工艺有效地消除了缩松缩孔缺陷,从而获得了合理的铸造工艺方案. 相似文献
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铸件计算机凝固模拟的现状、发展与前景 总被引:2,自引:0,他引:2
计算机凝固模拟已经取得令人注目的成就,可以协助设计人员改进工艺设计,提高铸件质量。但是凝固模拟软件需要在铸件凝固的物理模型,计算机数值计算,铸件的三维成形,初始条件和边界条件确定,热物性数据的测量,铸件缺陷的预测及显示等多方面进行改进以更大程度上满足铸造生产的实际需要。在未来很长时期内,凝固模拟作为一个有力的工具,仍然需要有实际铸造工艺设计经验的专家使用才能发挥其作用与潜力。另一方面,铸造生产厂家必须严格生产过程控制,正确使用凝固模拟软件,加强对技术人员的培训和不断积累使用凝固模拟软件的经验,这是生产高质量铸件的需要,也是成功应用凝固模拟软件的重要条件。 相似文献
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Numerical simulation technology was applied for optimizing the casting design and conditions in large cast iron castings for marine engine. By the simulation of mold filling and solidification sequences the problems of the previous casting conditions were analyzed and marked improvements for large cylinder liner parts were derived from these results. Especially the amount and positions of chills were optimized to increase the mechanical properties and to minimize the shrinkage and microporosity in the castings. Ultrasonic testing, penetration testing and mechanical property testing were carried out for the parts with the modified casting conditions. It showed that no defects in the castings were found and the productivity could be distinctly increased. The mechanical properties satisfied also the specification demanded. 相似文献
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介绍了缓速器箱体铸件的技术要求及技术难点.为确保铸件质量,采用CAE软件对铸件进行凝固模拟分析,严格控制炉料质量和铁液化学成分,采用合理的球化、孕育处理工艺,4件铸件试生产结果显示:铸件表面质量良好,力学性能达到规定要求,铸件超声波探伤和表面着色探伤检测均达到了客户的要求,机械加工后没有发现任何铸造缺陷. 相似文献
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高铬铸铁具有良好的耐磨性,但由于其高脆性,通常只用于生产形状简单,体积较小的铸件,为了用高铬铸铁生产挖泥泵叶轮,进行了相应的工艺试验。通过合理的设计铸造工艺,利用计算机凝固模拟技术,同时严格控制现场生产过程,可成功地生产出形状复杂,质量较大的高铬铸铁叶轮。其工艺可供同行参考。 相似文献
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高铬铸铁具有良好的耐磨性,但它是一种脆性材料,通常只用于生产形状简单、体积较小的铸件。通过合理设计铸造工艺,利用计算机凝固模拟技术,同时严格控制现场生产过程,成功地生产出形状复杂、质量较大的高铬铸铁叶轮。铸件经粗加工和探伤,性能达到技术要求。 相似文献
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高铬铸铁具有良好的耐磨性,但脆性较严重,通常只用于生产形状简单,尺寸较小的铸件。通过设计合理的铸造工艺,利用计算机凝固模拟技术,同时严格控制生产过程,成功地生产出了形状复杂的大型高铬铸铁叶轮。 相似文献
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Most lost-foam casting processes involve non-equilibrium solidification dominated by kinetic factors, while construction of a common dynamic solidification curve is based on pure thermodynamics, not applicable for analyses and research of non-equilibrium macro-solidification processes, and the construction mode can not be applied to nonequilibrium solidification process. In this study, the construction of the dynamic solidification curve (DSC) for the nonequilibrium macro-solidification process included: a modified method to determine the start temperature of primary austenite precipitation (TAL) and the start temperature of eutectic solidification (TES); double curves method to determine the temperature of the dendrite coherency point of primary austenite (TAC) and the temperature of eutectic cells collision point (TEC); the "technical solidus" method to determine the end temperature of eutectic reaction (TEN). For this purpose,a comparative testing of the non-equilibrium solidification temperature fields in lost-foam casting and green sand mold casting hypoeutectic gray iron was carried out. The thermal analysis results were used to construct the DSCs of both these casting methods under non-equilibrium solidification conditions. The results show that the transformation rate of non-equilibrium solidification in hypoeutectic gray cast iron is greater than that of equilibrium solidification. The eutectic solidification region presents a typical mushy solidification mode. The results also indicate that the primary austenite precipitation zone of lost-foam casting is slightly larger than that of green sand casting. At the same time, the solid fraction (fs) of the dendrite coherency points in lost-foam casting is greater than that in the green sand casting.Therefore, from these two points, lost-foam casting is more preferable for reduction of shrinkage and mechanical burntin sand tendency of the hypoeutectic gray cast iron. Due to the fact that the solidification process (from the surface to center) at primary austenite growth area in the lost-foam cylinder sample lags behind that in the green sand casting,the mushy solidification tendency of lost-foam casting is greater and the solidification time is longer. 相似文献