【作者】 黄刚；

【导师】 叶升平；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2014， 硕士

【摘要】 消失模铸造工艺凭借其设计自由度高、加工余量少等优点，在我国得到了迅速发展。然而，消失模球铁件的碳渣孔缺陷却始终困扰着许多铸造厂家。为减少球铁件的碳渣孔缺陷，本文探索了单层涂料和无薄膜密封两项工艺措施。针对QT500-7制动钳铸件的渣孔缺陷，本文采用电镜扫描和能谱分析的实验方法对其进行重点研究。通过孔内形貌的观察、成分的分析，确定制动钳的渣孔为碳渣孔，并由此得出碳渣孔缺陷的两种判定方法。为解决QT450-10轴承座的碳渣孔问题，本文尝试采用单层涂料工艺。对台湾消失模涂料进行透气性测试，得出单层/双层涂料的透气性能。通过控制单层涂料厚度及涂料浸挂层数，进行一系列轴承座铸造实验，以期获得合理的单层涂料工艺参数。为减少制动钳的碳渣孔缺陷，本文尝试采用无薄膜密封工艺。通过无薄膜密封的理论分析，探索了薄膜对白模热解环境的影响。在此基础上，以共聚物白模为载体，进行有/无氧两种气氛下的白模热解实验。通过热重和红外光谱分析，研究无薄膜密封的内在机理，并探索氧气对白模热解产物的影响。本文将有无薄膜密封、浇注压头高度、真空泵负压度以及涂层厚度作为变量，完成了单层/多层串浇制动钳铸造实验，并探索了各因素对碳渣孔缺陷的影响。通过单层涂料和无薄膜密封两种工艺的结合，得出合理的铸造方案。更多还原

【Abstract】 The lost foam casting in our country has been developed rapidly due to its high degreeof design’s freedom, less allowance and so on. However, the carbon dross hole defect ofductile iron has always been bothering the lost foam casting factories. In order to solve thecarbon dross hole defect of ductile iron, the process of single-layer coating and no-filmsealing is explored.The experimental method of electron microscope scanning and energy spectrum isused to study the QT500-7caliper body’s dross hole. The type is confirmed as carbondross hole by observing the appearance and analyzing the component in the hole. And twoidentify methods of carbon dross hole are obtained.The single-layer coating process is used to solve the problem of QT450-10bearing’scarbon dross hole. The permeability of single-layer coating&double-layer coating hasbeen compared by testing Taiwan’s LFC coating. It’s expected to obtain the reasonableprocess parameters with a series of casting experiments by controlling single-layercoating’s thickness and coating’s layers.The no-film sealing process is attempted to reduce the caliper body’s carbon drosshole defect. The impact of film on foam’s pyrolysis environment is explored with no-filmsealing’s theoretical analysis. On the basis of that, a foam’s pyrolysis experiment isconducted under the oxygen or anoxic atmosphere by using copolymer mould as carrier.The no-film sealing’s inner mechanism is researched with the analysis ofthermogravimetric and infrared spectral, and the impact of oxygen on foam’s pyrolysisproduct is explored.The casting experiments of single-layer caliper body and multi-layer caliper body areconducted by changing the presence of film sealing, the height of pouring, the degree ofvacuum pressure and the thickness of coating, the influence of various factors onthe carbon dross hole is explored. The reasonable casting scheme is got with the combination of single-layer coating and no-film sealing process.更多还原