固定自耗电极充填法熔铸的数值模拟

发布时间：2018-01-17 22:27

本文关键词：固定自耗电极充填法熔铸的数值模拟　出处：《辽宁工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：电渣熔铸以精炼和凝固双优特长,成为高品质铸件的重要生产方法。受到公共型腔限制,到目前为止用电渣熔铸法铸造形状复杂铸件仍无突破性进展。为此,提出了固定自耗电极充填法熔铸形状复杂铸件的新方法。固定自耗电极充填工艺在实施之前急需解决以下问题:(1)固态渣启动电渣炉时,如果移动自耗电极所化熔渣不能与固定自耗电极接触,则铸件的熔铸过程就无法正常启动,故必须弄清移动自耗电极所化熔渣的水平长度;(2)熔铸过程中移动自耗电极与固定自耗电极双重熔化条件下两个金属熔池能否互通。针对上述问题,首先推导出一个符合固定自耗电极充填法熔铸过程的数学模型、建立起相应的偏微分方程和恰当的边界条件,并编写程序,计算了熔铸初期固定自耗电极下端斜度不同的熔铸系统的温度场,并通过实验验证了温度场数值模拟的准确性。在此基础上,计算了不同工艺参数下固定自耗电极充填法熔铸初期化渣过程熔渣水平长度、熔铸达到稳定阶段时的熔池间距。结果表明,铸锭底部形状数值模拟结果与实验结果基本吻合。通过数值模拟发现,初期化渣过程中熔渣水平长度的有效距离和底水箱表面的水平长度随着电流密度、电极宽度和电极厚度增加而增加且电极宽度有一个最大值,电极的横截面形状越细长熔渣的水平长度越短。熔铸达到稳定阶段时随着电流密度的增大,熔池间距减小,当电流密度足够大时两金属熔池互通;随着电极宽度的增加,熔池间距减小,并且电极宽度增加是有一定限度的;随着电极厚度的增加,熔池间距逐渐减小;随着电极间距的增加,熔池间距变大;电极的横截面形状越细长,熔池间距越大,越不利于两金属熔池互通。
[Abstract]:Electroslag melting casting has become an important production method for high quality castings by refining and solidifying, which is limited by common cavity. So far, there has been no breakthrough in electroslag casting with complex shape castings. In this paper, a new method of fixed consumable electrode filling is put forward, which is urgent to solve the following problems before the implementation of the fixed consumable electrode filling process, when the solid slag starts up the electroslag furnace, it is urgent to solve the following problems before the implementation of the fixed consumable electrode filling process. If the slag can not contact with the fixed electrode, the casting process will not start normally, so the horizontal length of the slag should be made clear. 2) whether the two metal melting pools can interoperate under the condition of double melting of the moving consumable electrode and the fixed consumable electrode in the process of melting and casting. At first, a mathematical model of the melting and casting process in accordance with the fixed consumable electrode filling method is derived, and the corresponding partial differential equation and appropriate boundary conditions are established, and the program is written. The temperature field of the molten casting system with different slope at the lower end of the fixed consumable electrode in the initial stage of melting and casting is calculated, and the accuracy of the numerical simulation of the temperature field is verified by experiments. The horizontal length of slag in the initial slagging process of fixed consumable electrode filling method was calculated under different process parameters, and the melting pool spacing was calculated when the melting process reached the stable stage. The numerical simulation results of the bottom shape of the ingot are in good agreement with the experimental results. It is found that the effective distance of the slag horizontal length in the initial slagging process and the horizontal length of the bottom water tank surface with the current density. With the increase of electrode width and electrode thickness, the electrode width has a maximum value, the smaller the electrode cross section shape is, the shorter the horizontal length of slag is. When the melting casting reaches the stable stage, the current density increases. When the current density is large enough, the two metal melting pools interoperate; With the increase of electrode width, the distance between the melting pool decreases and the electrode width increases to a certain extent. With the increase of electrode thickness, the melting pool spacing decreases gradually. With the increase of electrode spacing, the melting pool spacing becomes larger. The longer the cross section of the electrode is, the greater the weld pool spacing is, which is not conducive to the interworking of the two metal melting pools.
【学位授予单位】：辽宁工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TF14;TG24

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