钻削高温合金的切屑形成机理及刀具磨损研究

发布时间：2018-05-09 09:38

本文选题：高温合金 + 钻削　；参考：《沈阳理工大学》2017年硕士论文

【摘要】：高温合金材料因其强度高、质量轻等优良力学性能,被广泛应用于航空航天等领域。然而,由于高温合金材料各向异性的特征,使其在加工过程中易出现毛刺等缺陷,严重影响其加工精度,特别是孔加工;另外,材料导热性差且硬度高,这些特点导致其在加工时刀具磨损严重;这些问题的存在严重影响着高温合金材料在各个领域的应用和发展。针对现阶段高温合金材料在切削加工方面存在的问题,为找到钻削高温合金时切削用量与切屑形成及刀具磨损的关系,本文研究的内容包括以下几个方面:首先,在研究了麻花钻的基本结构和几何参数基础上,利用三维建模软件UG设计了钻头三维实体模型。运用有限元仿真软件DEFORM-3D建立钻头钻削仿真模型,选用Usui’s模型为材料磨损模型,设置步数、步长、钻削条件及切削参数,选择合适迭代方法和求解器,最终实现了钻削过程模拟仿真。最后,在不同切削参数和几何结构进行正交实验,利用有限元仿真软件DEFORM-3D的后处理分析可以得到钻削温度、刀具磨损以及切屑的形态等数据,并搭建钻削实验研究平台,利用高速钢钻头和硬质合金钻头两种不同的刀具,采用单因素方法得到在钻削过程中不同刀具、不同切削用量的条件下的刀具磨损变形规律和切屑形态,并与仿真结果进行对比,我们可得出以下结论:(1)钻削高温合金时的磨损机理有磨粒磨损、粘结磨损、氧化磨损及扩散磨损,而磨粒磨损和粘结磨损是最主要的形式。(2)主切削刃和横刃是高温合金GH4169在钻削过程中温度较高的区域,刀具磨损都随转速和进给量的增大而增加,当转速和进给量增加时,产生的热量加快,温度升高,刀具磨损加重。(3)增大切削速度和进给量均会加剧刀具的磨损,但二者相比较而言,增大进给量对加剧刀具磨损的作用较小。通过增加进给量来提高钻削高温合金的切削效率,有利于延长刀具使用寿命、抑制刀具磨损的加剧。(4)高温合金钻削后产生的切屑形态大多呈现为长带状的螺卷屑,当转速为1000 r/min,进给量为0.08mm/r时硬质合金钻头产生的切屑最有利于钻削。切削速度越大,切屑的变形程度越小,更有助于切屑的形成;进给量越大,切屑变形系数也随着增大,切屑形状卷曲程度越大,切屑卷曲半径减小,断屑效果越好。另外,刀具的顶角及螺旋角对切屑形态的影响较小。
[Abstract]:High-temperature alloy materials are widely used in aeronautics and spaceflight because of their high strength and light mechanical properties. However, due to the anisotropy of superalloy materials, it is easy to appear burr and other defects in the process of processing, which seriously affects the machining accuracy, especially the hole machining, in addition, the thermal conductivity of the materials is poor and the hardness is high. These characteristics lead to serious tool wear during machining, and the existence of these problems seriously affects the application and development of superalloy materials in various fields. In order to find out the relationship between cutting parameters and chip formation and tool wear, the contents of this paper include the following aspects: first of all, in order to find out the relationship between cutting parameters and chip formation and tool wear during drilling of superalloy materials, the main contents of this paper are as follows: first of all, On the basis of studying the basic structure and geometric parameters of twist drill, the 3D solid model of drill bit is designed by using the 3D modeling software UG. The simulation model of drill bit drilling is established by using the finite element simulation software DEFORM-3D. The Usui's model is selected as the material wear model, the step number, step size, drilling condition and cutting parameters are set up, and the appropriate iterative method and solver are selected. Finally, the simulation of drilling process is realized. Finally, through orthogonal experiments with different cutting parameters and geometric structures, the data of drilling temperature, tool wear and chip shape can be obtained by post-processing analysis of finite element simulation software DEFORM-3D, and a drilling experimental research platform is built. By using two different cutting tools, high speed steel bit and cemented carbide bit, single factor method is used to obtain the wear deformation law and chip shape of cutting tool with different cutting tools and different cutting parameters during drilling. Compared with the simulation results, we can draw the following conclusion: the wear mechanism of drilling superalloy is abrasive wear, bond wear, oxidation wear and diffusion wear. The abrasive wear and bond wear are the most important form. (2) the main cutting edge and the chisel edge are the regions with higher temperature in the drilling process of superalloy GH4169. The tool wear increases with the increase of speed and feed rate, and when the rotational speed and feed rate increase, The increase of cutting speed and feed rate will increase the wear of cutting tool, but the increase of feed rate has little effect on the increase of tool wear. By increasing the feed rate to improve the cutting efficiency of drilling superalloy, it is beneficial to prolong the tool service life and restrain the aggravation of tool wear. When the speed is 1000 r / min and the feed rate is 0.08mm/r, the chip produced by the cemented carbide bit is most favorable for drilling. The larger the cutting speed is, the smaller the chip deformation degree is, and the more the feed is, the larger the chip deformation coefficient is, the larger the chip shape crimp degree is, the smaller the chip crimp radius is, and the better the chip breaking effect is. In addition, the tip angle and helical angle of the cutting tool have little effect on the chip shape.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG52

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