多维振动下型腔内金属液充型与凝固规律研究

发布时间：2018-05-31 16:04

本文选题：多维振动 + 振动铸造　；参考：《安徽理工大学》2017年硕士论文

【摘要】：铸造作为机械部件的重要成形方法,其技术水平的提高能极大促进国家工业发展。为了实现铸件"复杂化、薄壁化、大型化"的目标,不断有新的铸造技术问世。多维振动铸造技术是振动铸造技术的进一步改进优化。通过改变振动铸造参数中的自由度、振幅、频率等参数能够有效提高金属液在型腔中的充型能力,并对金属液的补缩产生促进作用。本文在充分研究了国内外先进振动铸造技术及理论的基础上,利用数值模拟软件EDEM-Fluent及ProCAST模拟金属液在型腔内的流动及收缩行为,并利用自主设计研制的多维振动装置及模具进行了水力实验和基于微晶蜡的物理模拟实验。主要研究工作如下:(1)对振动装置进行计算,得出相应的振动参数。采用L形充型试样对振动参数进行筛选,研究自由度、振幅、频率对流体在型腔内流动能力的影响。选取具有代表性的参数,利用自选模型进行EDEM-Fluent耦合模拟,通过对充型过程中的颗粒运动情况分析,得出各个振动工况下颗粒的运动状态。利用正交参数实验法得出型腔考察区域中颗粒的数目,通过极差分析法分析得出颗粒对振动自由度、振动频率、振动幅度的响应度。(2)考虑到ProCAST不能进行振动铸造模拟,选取三个金属液浇注的一般性参数浇注速度、浇注温度、砂箱温度分析其对自选模型内收缩情况的影响。利用正交实验法,得出浇注参数中对金属液凝固收缩影响次序及最佳的浇注方案为物理模拟实验做参考。以最佳方案参数为标准,采用单一变量法,研究同一参数的变化对铸件缩松缩孔体积的影响。(3)通过水力实验及基于微晶蜡的物理模拟实验,模拟振动充型及振动凝固过程。采用与数值模拟相同的实验方案进行浇注,用数码相机记录振动条件下流体的流动行为,分析得出振动参数与流体充型状态及时间之间的关系,对数值模拟结果进行论证;依据ProCAST模拟得出的最佳参数及相似性准则对微晶蜡的熔化温度计算,使其满足与原型相似。为了保证实验的连续性,采用振动充型时的方案进行振动浇注,用表面收缩体积代替缩松体积进行计量,通过方差分析法确定最适宜的凝固补缩的振动方案。
[Abstract]:As an important forming method of mechanical parts, the improvement of foundry technology can greatly promote the development of national industry. In order to realize the goal of "complication, thin-wall and large size", new casting technology has been developed. Multi-dimensional vibration casting technology is a further improvement and optimization of vibration casting technology. By changing the degree of freedom, amplitude, frequency and other parameters of vibratory casting, the filling capacity of liquid metal in the mold cavity can be improved effectively, and the feeding effect of liquid metal can be promoted. Based on the study of advanced vibratory casting technology and theory at home and abroad, the numerical simulation software EDEM-Fluent and ProCAST are used to simulate the flow and shrinkage behavior of molten metal in the cavity. The hydraulic experiment and the physical simulation experiment based on microcrystalline wax were carried out by using the multi-dimensional vibration device and die designed by ourselves. The main research work is as follows: (1) the vibration device is calculated and the corresponding vibration parameters are obtained. The effects of degrees of freedom, amplitude and frequency on the flow capacity of the fluid in the cavity were studied by selecting the vibration parameters of the L-shaped filling sample. The representative parameters are selected and the EDEM-Fluent coupling simulation is carried out by using the self-selection model. Through the analysis of the particle motion in the filling process, the moving state of the particles under various vibration conditions is obtained. The number of particles in the investigation area of the cavity is obtained by orthogonal parameter experiment, and the response degree of particle to vibration degree of freedom, vibration frequency and vibration amplitude is obtained by means of range analysis. 2) considering that ProCAST can not be used to simulate vibration casting, The effects of pouring speed, pouring temperature and sand box temperature on the shrinkage of the selected model were analyzed. By means of orthogonal experiment, the order of influence of pouring parameters on solidification shrinkage of molten metal and the best pouring scheme are obtained for reference of physical simulation experiment. The effect of the change of the same parameter on the volume of shrinkage of castings was studied by single variable method. The process of vibration filling and vibration solidification was simulated by hydraulic experiments and physical simulation experiments based on microcrystalline wax. Using the same experimental scheme as numerical simulation, the flow behavior of fluid under vibration condition is recorded by digital camera, and the relationship between vibration parameters and filling state and time of fluid is obtained, and the numerical simulation results are demonstrated. The melting temperature of microcrystalline wax is calculated according to the optimum parameters and similarity criterion obtained by ProCAST simulation, which is similar to the prototype. In order to ensure the continuity of the experiment, the vibratory pouring was carried out by the method of vibration filling, and the surface shrinkage volume was used instead of the shrinkage volume to be measured. The most suitable vibration scheme for solidification and shrinkage was determined by the method of variance analysis.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG211

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