WC-Co硬质合金的摩擦磨损性能研究

发布时间：2018-11-17 07:07

【摘要】：高压旋转喷头以其打击力度大,清洗效果好等特点受到人们的高度重视。喷嘴总成作为高压旋转喷头的关键部件,其耐磨性能直接关系到旋转喷头的使用寿命。为合理选择喷嘴、喷芯的材料,论文对硬质合金/硬质合金、硬质合金/陶瓷摩擦副的摩擦磨损性能开展了研究,并进一步分析了WC-Co硬质合金微观结构参数对其磨损性能的影响。以WC晶粒尺寸为0.77μm、Co相含量为11.6 wt.%的硬质合金分别与YG6X硬质合金球、Si3N4陶瓷球组成摩擦副进行了摩擦磨损试验,考察了摩擦行程、法向载荷、往复速度以及试样表面粗糙度对摩擦副摩擦磨损性能的影响。在试验基础上,通过比较两种摩擦副的磨损体积和比磨损率,并结合高压旋转喷头的服役条件,对摩擦副的材料进行了选择。结果表明,摩擦副中硬质合金的耐磨性受其配副材料的影响,硬质合金/硬质合金摩擦副的耐磨性优于硬质合金/Si3N4陶瓷摩擦副。试验过程中,法向载荷与往复速度对不同的摩擦副的磨损量的影响程度不同。硬质合金/硬质合金摩擦副的磨损量,受所施加的法向载荷、往复速度的影响较小。而法向载荷和往复速度的变化,对硬质合金/Si3N4陶瓷摩擦副的磨损量影响显著,其磨损量随法向载荷的增大呈线性增加,随往复速度的增大,磨损量增加。制备了一系列具有不同微观结构参数的硬质合金试样,通过测量试样与YG6X硬质合金球磨损试验过程中的磨损量变化,探索了硬质合金微观结构参数对其磨损性能的影响。利用扫描电子显微镜(SEM)、X射线能谱仪(EDS)及超景深光学显微镜(OM)等检测仪器,对WC-Co硬质合金的磨损机理进行了初步的分析。结果表明,硬质合金的微观结构参数对其磨损性能有很大的影响。相同Co含量条件下,硬质合金中WC的粒径越小,耐磨性越高;WC粒径相同时,低Co含量的硬质合金表现出更好的耐磨性。试验过程中,硬质合金的磨损机理主要是刮擦、WC晶粒的破碎剥落和Co相的涂抹。法向载荷对于硬质合金的磨损机理有明显的影响,法向载荷较小的情况下,硬质合金的磨损机理多表现为刮擦。随着法向载荷的增大,硬质合金的磨损机理逐渐转变为犁沟、WC晶粒的破碎、剥落,以及Co相的涂抹。对于硬质合金/硬质合金摩擦副,只有摩擦副的两种材料均选用低Co含量、细WC晶粒的硬质合金材料,才能使得摩擦副的磨损量较小且一致。在上述研究基础上,制备了WC粒径0.6μm、6 wt.%Co的硬质合金喷嘴和喷芯进行了应用考核。结果表明,在500 bar水压下,高压旋转喷头的喷嘴、喷芯的使用寿命达100 h以上,满足零件清洗质量的要求。
[Abstract]:High-pressure rotary sprinkler is highly valued for its strong impact and good cleaning effect. Nozzle assembly is a key component of high pressure rotary nozzle, and its wear resistance is directly related to the service life of rotary nozzle. The friction and wear properties of cemented carbide / cemented carbide, cemented carbide / ceramic friction pair were studied in this paper. The effect of microstructure parameters on wear properties of WC-Co cemented carbide was further analyzed. The friction and wear tests were carried out between cemented carbide with WC grain size of 0.77 渭 m Co phase of 11.6 wt.% and YG6X cemented carbide ball and Si3N4 ceramic ball respectively. The friction stroke and normal load were investigated. Effects of reciprocating speed and surface roughness on friction and wear properties of friction pairs. On the basis of the experiments, the wear volume and specific wear rate of the two friction pairs were compared, and the materials of the friction pairs were selected according to the service conditions of the high pressure rotary sprinklers. The results show that the wear resistance of cemented carbides in friction pairs is affected by their matching materials, and the wear resistance of cemented carbide / cemented carbide friction pairs is better than that of cemented carbide / Si3N4 ceramic friction pairs. During the test, the normal load and the reciprocating velocity have different effects on the wear of different friction pairs. The wear rate of the cemented carbide / cemented carbide friction pair is less affected by the normal load applied. The change of normal load and reciprocating velocity has a significant effect on the wear of cemented carbide / Si3N4 ceramic friction pair. The wear rate increases linearly with the increase of normal load, and increases with the increase of reciprocating velocity. A series of cemented carbide samples with different microstructure parameters were prepared. The effects of microstructure parameters on the wear properties of cemented carbide were investigated by measuring the wear amount of the specimens and YG6X cemented carbide ball during the wear test. The wear mechanism of WC-Co cemented carbide was preliminarily analyzed by means of scanning electron microscope (SEM) (SEM), X ray energy spectrometer (EDS) and hyper-depth of field optical microscope (OM). The results show that the microstructure parameters of cemented carbides have great influence on the wear properties of cemented carbides. Under the same Co content, the smaller the particle size of WC in cemented carbide, the higher the wear resistance, and the better wear resistance of low Co content cemented carbide with the same WC particle size. During the test, the wear mechanism of cemented carbides is mainly scraping, breaking and spalling of WC grains and smearing of Co phase. The normal load has obvious influence on the wear mechanism of cemented carbides. When the normal load is small, the wear mechanism of cemented carbides appears as scraping. With the increase of normal load, the wear mechanism of cemented carbide is gradually changed into ploughing, WC grain breaking, spalling, and Co smear. For the cemented carbide / cemented carbide friction pair, the wear amount of the friction pair can be reduced and consistent only when the friction pair is made of low Co content and fine WC grain cemented carbide material. On the basis of the above research, the cemented carbide nozzle and core with WC diameter of 0.6 渭 m ~ (6) wt.%Co were prepared and tested. The results show that under 500 bar water pressure, the service life of the nozzle with high pressure rotating nozzle is more than 100h, which meets the requirements of parts cleaning quality.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG135.5

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