粉末药型罩旋压相对密度数值模拟及均匀性评价

发布时间：2018-01-21 10:39

本文关键词： 粉末药型罩旋压数值模拟相对密度均匀性　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着全球工业化的发展,石油作为现阶段最主要的能源物质而备受重视,在石油开采中广泛使用的聚能射孔技术也成为了研究热点,聚能射流技术同样适用于国防中。药型罩是聚能射流的关键部件,其均匀性优劣直接影响着射流效果。粉末冶金法制备粉末药型罩具有成分配比灵活、穿孔后效大的优点,是现阶段药型罩的主要加工方法。但是,如果压制工艺选择不当,会导致加工的药型罩存在成分及孔隙分布不均匀等缺陷。这些缺陷会使聚能射流偏离轴线,影响穿深效果,严重时可能出现射流过早断裂的现象。本文以粉末药型罩为研究对象,建立了金属粉末药型罩旋压加工的有限元模型,模拟了旋压工艺参数对其相对密度及粉末流动性的影响；定义了面密度的概念,完成了粉末药型罩面密度均匀性的检测。具体研究内容及结果如下：(1)应用有限元分析软件MSC.Marc,在金属塑性力学基础上,建立了金属粉末药型罩连续体有限元模型,分析了不同模壁摩擦系数、不同凹模转速、不同凸模压力对成形后药型罩相对密度的影响,并比较了相同摩擦系数下,旋压和普通压制对成形后相对密度的影响。模拟结果表明：在粉末药型罩旋压加工及普通压制中,相对密度均随着模壁摩擦力的增大而减小,但均匀性均随之得到提高；增加凹模旋转和增大凸模压力可以有利于改善压实效果,而且随着转速的增大,相对密度随之增大,但均匀性降低。(2)在MSC.Marc中建立了金属粉末药型罩多粒子有限元模型,模拟了粉末颗粒的流动规律：相比于普通压制,旋压加工中粉末颗粒的流动性有了明显的改善,这对复合粉末的压制有着重要意义,粉末的流动性随着摩擦系数的增大而减弱。(3)使用JSM-5600LV扫描电子显微镜对试样成分判定,徕卡公司MEF-3金相显微镜采集试样金相,对采集的金相图先用MATLAB进行降噪处理,再用图像分析软件Image-Pro-Plus软件对金相图片进行分析。分析结果表明：轴向孔隙率的模拟与实验结果一致性良好,误差为4.97%,证明了建立模型的可靠性；计算出了由模拟中确定的旋压参数生产的粉末药型罩面密度分布信息,对旋压参数的改进提出了相应的意见。本文采用数值模拟方法揭示了旋压工艺参数对相对密度分布及粉末流动性的影响,提出了一种新的药型罩均匀性评价方法,对指导粉末药型罩生产、提升粉末药型罩旋压加工质量具有重要理论和实践意义。
[Abstract]:With the development of global industrialization, petroleum, as the most important energy material, has been paid more attention at this stage. The technology of shaped energy perforation, which is widely used in petroleum exploitation, has also become a research hotspot. The shaped jet technology is also suitable for national defense. The powder mask is the key component of the shaped jet, and its uniformity directly affects the jet effect. The powder metallurgy method has a flexible composition ratio. The advantage of large perforation effect is the main processing method of the charge cover at the present stage. However, if the pressing process is not properly selected. These defects will lead to some defects such as uneven distribution of components and pores, which will cause the shaped jet to deviate from the axis and affect the penetration effect. In this paper, the finite element model of metal powder powder mask spinning processing is established. The influence of spinning process parameters on the relative density and powder fluidity was simulated. The concept of surface density is defined and the uniformity of powder covering density is tested. The specific research contents and results are as follows: 1) the finite element analysis software MSC.Marc is used. On the basis of metal plastic mechanics, the finite element model of metal powder powder liner continuum was established, and the influence of different die wall friction coefficient, different die speed and different punch pressure on the relative density of the metal powder powder cover was analyzed. The effects of spinning and ordinary pressing on the relative density after forming were compared under the same friction coefficient. The relative density decreases with the increase of the friction force of the die wall, but the uniformity increases with the increase of the friction force of the die wall. Increasing the rotation of the die and increasing the pressure of the punch can improve the compaction effect, and the relative density increases with the increase of the rotational speed. But the uniformity is reduced. (2) the multi-particle finite element model of metal powder powder mask is established in MSC.Marc, and the flow law of powder particle is simulated: compared with ordinary compaction. The fluidity of powder particles has been improved obviously in spinning process, which is of great significance to the compaction of composite powder. The fluidity of the powder decreases with the increase of friction coefficient. 3) JSM-5600LV scanning electron microscope is used to judge the composition of the sample, and Leica MEF-3 metallographic microscope is used to collect the metallography of the sample. The acquired metallographic diagram is first processed by MATLAB. The results show that the simulation of axial porosity is in good agreement with the experimental results, and the error is 4.97%. The reliability of the model is proved. The density distribution information of powder type covering produced by spinning parameters determined in simulation is calculated. The influence of spinning parameters on relative density distribution and powder fluidity was revealed by numerical simulation. In this paper, a new method for evaluating the uniformity of powder mask is put forward, which has important theoretical and practical significance in guiding the production of powder powder cover and improving the quality of spinning processing.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE925.3

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