石墨对金属结合剂金刚石工具性能影响的研究

发布时间：2018-07-25 16:29

【摘要】：金属结合剂金刚石工具具有结合强度高、耐磨性良好和使用寿命较长等优点,占据了金刚石制品中很大的市场,是工业生产和发展中重要的工具。但是,金属结合剂金刚石工具仍存在气孔率低、出刃性差和自锐困难等问题。本文选取石墨作为添加剂,力图解决金属结合剂金刚石工具遇到的问题。石墨与金属结合剂胎体结合强度差,以游离状态存在于胎体之中,提高胎体的孔隙率,起到排屑、冷却和促进自锐的作用;石墨可以弱化金属结合剂胎体,使金属结合剂胎体与金刚石磨料的耐磨性相匹配,提高金刚石工具的综合性能。本文基于单一变量法确定石墨的影响因素和水平,再利用正交试验,围绕金属结合剂金刚石工具的磨耗比、力学性能、磨削速度和使用寿命进行研究。分析实验结果,从而得出以下结论:(1)通过正交试验分析,石墨对金属结合剂金刚石工具性能影响的顺序为:石墨含量最大,石墨种类次之,石墨粒度最小;(2)通过正交试验分析,当金刚石的粒度为70/80目时,石墨对铜基结合剂金刚石工具性能影响的最佳方案为:石墨种类为鳞片状石墨,石墨粒度为80目和石墨含量为3wt%。根据最佳方案制备出实验试样并测试性能,其磨耗比最大值可达206.62,相较于基准样的磨耗比提高了43.12%;与基准样的力学性能相比较,其抗弯强度和硬度分别降低了32.98%和16.13%,而冲击强度提高了5.67%;(3)通过正交试验分析,当金刚石的粒度为70/80目时,石墨对铁基结合剂金刚石工具性能影响的最佳方案为:石墨种类为土状石墨,石墨粒度为120目和石墨含量为3wt%。根据最佳方案制备出实验试样并测试性能,其磨耗比最大值可达287.58,与基准样的磨耗比相比较,提高了3.30%;相较于基准样的力学性能,其抗弯强度和冲击强度分别降低了34.16%和21.65%,而硬度几乎不变;(4)金属结合剂金刚石工具的使用寿命和锋利度是此消彼长的联系,提高工具的锋利度和磨削速率,必定会减少使用寿命。相较于基准磨边轮,含有石墨的铜基磨边轮比基准磨边轮的最大磨削速度提高了7.89%,其使用寿命降低了20.63%;含有石墨的铁基磨边轮比基准磨边轮的最大磨削速度提高了6.99%,其使用寿命降低了19.28%;在此次实验中,虽然金属结合剂金刚石工具使用寿命降低,但是其足够满足生产的使用要求;更重要的一点,通过相应地降低寿命来提高锋利度和磨削速度,提高磨削对象磨削质量以及扩大金属结合剂金刚石工具的使用范围。
[Abstract]:Metal bond diamond tools have the advantages of high bonding strength, good wear resistance and long service life. They occupy a large market in diamond products and are important tools in industrial production and development. However, the metal bond diamond tools still have problems such as low porosity, poor edge and self-sharpening. In this paper, graphite is chosen as additive to solve the problems of metal bond diamond tools. Graphite has poor bonding strength with metal binder matrix, and exists in the matrix in a free state, which can improve the porosity of the matrix, play the role of chip removal, cooling and self-sharpening, and graphite can weaken the metal bond matrix. The wear resistance of diamond abrasive is matched with the matrix of metal bond, and the comprehensive properties of diamond tools are improved. Based on the single variable method to determine the influence factors and levels of graphite, the wear ratio, mechanical properties, grinding speed and service life of metal bond diamond tools were studied by orthogonal test. By analyzing the experimental results, the following conclusions are drawn: (1) through the orthogonal test, the order of the effect of graphite on the properties of metal bond diamond tools is as follows: the content of graphite is the largest, the type of graphite is the second, and the particle size of graphite is the least; (2) through the orthogonal test, When the grain size of diamond is 70 / 80 mesh, the best scheme for the effect of graphite on the properties of copper based diamond tools is as follows: graphite type is flake graphite, graphite particle size is 80 mesh and graphite content is 3 wtlong. The maximum wear ratio of the sample was 206.62, which was 43.12 higher than that of the reference sample, and compared with the mechanical properties of the standard sample. The bending strength and hardness were reduced by 32.98% and 16.13%, respectively, while the impact strength was increased by 5.67%. (3) by orthogonal test, when the grain size of diamond was 70 / 80 mesh, The best scheme for the effect of graphite on the properties of iron-based bond diamond tools is that the graphite type is earth graphite, the graphite particle size is 120 mesh and the graphite content is 3 wts. The maximum wear ratio of the sample was 287.58, which was 3.30% higher than that of the standard sample, and the mechanical properties of the standard sample were compared with that of the standard sample. The bending strength and impact strength decreased 34.16% and 21.65%, respectively, while the hardness was almost the same. (4) the service life and sharpness of the metal bond diamond tools increased the sharpness and grinding rate of the tools. The service life is bound to be reduced. Compared with the base grinding wheel, The maximum grinding speed of copper base edge grinding wheel with graphite is increased by 7.89, and its service life is reduced by 20.63. The iron base edge grinding wheel with graphite increases 6.99 and its service life is reduced by 6.99. In this experiment, Although the service life of metal bond diamond tools is reduced, they are sufficient to meet the requirements of production and, more importantly, to increase sharpness and grinding speed by reducing their life accordingly, Improve the grinding quality of grinding objects and expand the use of metal bond diamond tools.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ163

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