不锈钢板冷冲过程及其成形质量影响因素研究

发布时间：2018-10-15 10:22

【摘要】：近年来,随着电力行业的快速发展,对母线的需求增多,对质量的要求提高。冲孔作为一道重要工序对母线质量有直接的影响。目前我国面临的主要问题是冲裁技术的研究及应用水平较低,在一定程度上制约了我国制造业的发展。为了提高对板材冷冲过程及其成形质量因素的认识,采用广泛应用于各种领域的304不锈钢作为实验材料,主要是以冲裁间隙、压边力及其他种类的材料作为试验变量,对各个变量条件下冲裁过程中的等效应力、等效应变及材料的流动速率及流动方向进行描述。在模拟仿真中测量不同冲裁间隙条件下的光亮带长度、断面锥度、圆角带、毛刺长度以及冲裁过程中的最大冲裁力等的大小,分别利用matlab与试验变量进行数据拟合,研究试验变量对冲裁过程的影响,此外,还对比了不同材料的参数对冲裁的影响。最后在实验环节以冲裁间隙为变量,研究冲裁断面质量及冲裁过程中的冲裁力曲线图,并利用电镜对冲裁件的断面进行扫面,观察微观形貌。通过研究,首先在以冲裁间隙为试验变量的仿真中,随着冲裁间隙的增大,圆角带长度和高度、断面锥度均呈增大的趋势;实验中光亮带孔径尺寸受冲裁间隙的影响较大,即随其增大而增大,断裂带的孔径尺寸受冲裁间隙的影响并不明显;部分相同的研究因素在仿真和实验中的变化趋势基本一致。其次在仿真中分析了压边力对最大冲裁力、光亮带长度、圆角带长度的影响规律,但压边力对圆角带高度以及毛刺长度影响并不明显。此外冲裁过程中会在晶界处产生新的晶粒,并不断的长大,取代原有的晶粒,在一定程度上细化了晶粒的大小。塑性较好时,上端刃口处应力、应变较小,反之较大。最后通过电镜观察,当间隙较小时,圆角带与光亮带,光亮带与断裂带之间的过渡线比较均匀整齐,断面的韧窝现象越明显,随着间隙的增大,韧窝现象减少,表现为断面上出现小的剪切面,数量较多并呈台阶状。仿真和实验相结合的研究方法,不仅能够相互验证,而且能够相互补充,在一定程度上利于冲裁技术的发展。
[Abstract]:In recent years, with the rapid development of electric power industry, the demand for busbar increases and the requirement for quality increases. As an important process, punching has a direct impact on the quality of busbar. At present, the main problem in China is the low level of research and application of blanking technology, which restricts the development of Chinese manufacturing industry to a certain extent. In order to improve the understanding of cold blanking process and forming quality factors of sheet metal, 304 stainless steel, which is widely used in various fields, is used as experimental material, mainly with blanking clearance, blank holder force and other kinds of materials as experimental variables. The equivalent stress, equivalent strain, material flow rate and flow direction during blanking are described. In the simulation, the length of bright zone, the taper of section, the angle band, the burr length and the maximum punching force in the blanking process were measured under different blanking gaps. The data were fitted by matlab and the test variables, respectively. The effects of experimental variables on the hedging process are studied. In addition, the effects of different material parameters on the hedging process are compared. Finally, the quality of blanking section and the curve of blanking force in the process of blanking are studied with blanking gap as variable in the experiment link, and the scanning surface of the section of the blanking part is compared with the electron microscope, and the microscopic morphology is observed. First of all, in the simulation with blanking clearance as the test variable, with the increase of blanking gap, the length and height of the corner band and the taper of the section are all increasing, and the size of the aperture of the bright strip is greatly affected by the blanking gap. In other words, the pore size of the fault zone is not affected by the punching gap with the increase of the size of the fault zone, and the variation trend of some of the same research factors is basically the same in the simulation and experiment. Secondly, the influence of the blank holder force on the maximum blanking force, the length of the bright band and the length of the circular corner band is analyzed, but the influence of the blank holder force on the height of the corner band and the length of the burr is not obvious. In addition, new grains will be produced at grain boundaries in the process of blanking, and the grain size will be refined to a certain extent. When the plasticity is good, the stress and strain at the edge of the upper end are smaller, whereas the other is larger. Finally, when the gap is small, the transition line between the round corner zone and the bright zone, the bright zone and the fault zone is more uniform, the dimple phenomenon of the section is more obvious, and the dimple phenomenon decreases with the increase of the gap. It is shown that there are small shear planes on the cross section, a large number of them and a step shape. The research method combining simulation and experiment can not only verify each other, but also complement each other, which is beneficial to the development of blanking technology to some extent.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG386.2

【参考文献】