【作者】 佟富强；

【导师】 张飞虎；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2010， 博士

【摘要】 TiC系金属陶瓷材料具有优良的耐磨、耐氧化、耐腐蚀和力学性能,除了成功应用于刀具材料外,还可应用于拉丝模、各类发动机的高温部件及石化工业中各类密封件。TN85金属陶瓷是一种以镍基合金做为粘结剂,以难熔金属碳化物TiC、WC作为硬质相的复合材料。由于具备高硬度、高韧性、高抗弯强度、高耐磨损性能,在一些耐腐蚀、耐磨损等领域有广泛的应用前景。目前关于金属陶瓷的研究热点集中于烧结制备技术及面向应用的摩擦磨损性能、刀具切削性能等方面,而金属陶瓷实用化的超精密加工机理及技术的研究相对较少。因此探索金属陶瓷超精密加工技术及机理,促进其实用化变得日益紧迫和重要。现有的许多加工方法受到加工条件的限制而不能应用于具有小曲率半径凹球面偶件的超精密加工,因此小曲率半径的凹球面偶件超精密加工是目前加工所面临的重要难题。开发新型的适用于小曲率半径的凹球面偶件超精密加工方法有着重要的意义。ELID(Electrolytic in process dressing)磨削技术是超精密磨削新技术。本文针对TN85金属陶瓷难加工材料进行小曲率半径凹球面加工而采用的无专用修整电极ELID磨削技术是一种新的加工方法,属于探索性的基础研究工作。具体研究内容包括:综述了国内外关于金属陶瓷磨削去除机理,金属陶瓷磨削去除基础实验研究,ELID磨削技术和球面工件加工的研究现状和存在的问题,提出了本文的TN85金属陶瓷小球面偶件无专用电极ELID超精密磨削的研究内容。首先针对TN85金属陶瓷磨削去除机理进行了研究。在TN85金属陶瓷磨削去除中,由于TN85金属陶瓷本身的材料组成特点而形成了TN85金属陶瓷磨削过程中的微浮凸机理,由于这一磨削机理的存在使得许多加工方法达到超精密水平变得极为困难,而ELID磨削技术却能保证实现材料的软硬质相接近“均一化”去除;其次分析了TN85金属陶瓷材料的组成特点和磨削去除过程,在此基础上进行了压痕试验研究和单颗粒金刚石刻划试验研究,最后根据压痕和刻划试验所得到的材料硬度特性和刻划去除特点建立了TN85金属陶瓷磨削的去除模型。通过TN85金属陶瓷磨削试验后的表面微观形貌分析,对去除模型进行了验证;并在TN85金属陶瓷磨削去除机理研究基础上,进行微粉金刚石砂轮磨削去除基础试验研究,通过试验研究磨削去除过程,进一步解释验证了TN85金属陶瓷材料的磨削去除机制。在分析传统ELID磨削、间歇电解修锐ELID磨削、以工件做电极ELID磨削的原理基础上提出采用无专用修整电极ELID磨削技术方案磨削TN85金属陶瓷小球面偶件。针对无专用修整电极ELID磨削技术进行相关的基础性试验研究和凹球面工件做修整电极的应用性研究,研究结果证实了无专用修整电极ELID磨削技术在小球面偶件的超精密磨削中的可行性,为后续的进一步应用研究奠定了基础。针对TN85金属陶瓷小球面偶件无专用修整电极ELID超精密磨削技术中的两个关键技术指标:球面度和表面粗糙度的影响因素进行分析。研究结果表明:机床安装调整精度是磨削球面球度误差和球径误差的主要影响因素来源,而磨削采用的铸铁基微粉金刚石砂轮的磨粒粒度和结合剂种类则是表面粗糙度的主要影响因素。误差分析的结果为后续的小球面偶件超精密磨削技术的推广应用奠定了基础。最后,以工件兼做修整电极的间歇ELID磨削直径为12mmTN85金属陶瓷凹球面后粗糙度值Ra23.4nm。更多还原

【Abstract】 TiC cermets have excellent wear resistance, oxidation resistance, corrosion resistance and mechanical properties. It is not only used as tool materials successfully, but also can be applied in drawing mode, various engine parts under high-temperature and seals in petrochemical industry. TN85 cermets is one kind of composites, in which nickel alloy is binder and the hard phase is TiC, WC. TN85 with the excellent high hardness, high toughness, high bending strength, good wear resistance has a good extensive application prospect in corrosion and wear areas.At present, the research of metal-ceramic is focus on the sintering technology and the application-oriented friction and wear properties, however there is less research on ultra-precision machining mechanism and technology of cermets. So the research on the technology and ultra-precision machining mechanism of cermets is becoming increasingly urgent and important. Most of the existing processing methods can not be applied to the ultra-precision machining for the matching parts with small curvature radius concave spherical surface by limit of process conditions, therefore it is an important problem that the ultra-precision machining for the matching parts with small curvature radius concave spherical surface. It has the important significance for the development of new the ultra-precision machining technology for the matching parts with small curvature radius concave spherical surface.ELID (Electrolytic in process dressing) grinding technology with simple installation, low cost, portability and good features is the key technology to of ultra-precision grinding, and it has been studied in many countries extensively. In this paper, ELID grinding of non-specific electrode technique is a new method for TN85 cermets to machining small curvature radius concave spherical surface. It is an exploratory research, and this specific study includes:The general status of grinding removal mechanism for cermets, the experimental study of grinding removal for cermets, ELID (Electrolytic in process dressing) grinding technology and in both domestic and overseas is reviewed. ELID grinding without special electrode for the matching parts with small curvature radius concave spherical surface is developed.The grinding removal mechanism for cermets has been studied. During the process of the removal of TN85 cermets, the embossed mechanism is formed by material composition characteristics of TN85 cermets. It is difficult to achieve the ultra-precision level for most of the existing processing methods because of the embossed mechanism, however, the "uniform" removal of soft and hard phase can be realized by ELID grinding technique.The composition characteristics of TN85 cermets and the process of grinding removal are studied, and the removal model of TN85 cermets during grinding is developed. At last, the model is validated by the analysis of the surface micro-morphology of TN85 cermets after grinding. On the basis of the grinding removal mechanism of TN85 cermets, the basic study of the Indentation experiments, the characterization experiments of single-particle diamond and the grinding removal mechanism of micro power diamond grinding wheel has been conducted. Through basic experimental research, the hardness material properties and the characteristics of material grinding removal, the grinding removal mechanism of TN85 cermets has been verified and interprted.On the basis of the analysis of traditional ELID Grinding, ELID grinding intermittent electrolytic dressing, ELID grinding uses workpiece as dressing electrode, ELID grinding technique without special electrode is proposed to grind the matching parts with small curvature radius concave spherical surface. The study of the ELID grinding technique without special electrode is conducted, and the applied research on grinding experiments in which concave spherical parts is used as dressing electrode. The feasibility of ELID grinding technique without special electrode on the grinding of the matching parts with small curvature radius concave spherical surface is confirmed by above research, and it is the basis of the further applied research.The effects on both spherical degree and surface roughness in the ELID grinding technique without special electrode for the matching parts with small curvature radius concave spherical surface by two processing parameters. The results show that: The installation and adjustment precision of grinding machine is the main factor for spherical degree error and spherical diameter error, and the Granularity of micro power diamond grinding wheel cast iron base and the species of the bond is the main factor for surface roughness. The basis of follow-up popularization and application of the ultra-precision machining for particle reinforced metal matrix composites has been set up by the error analysis. The concave spherical surface of the TN85 cermets workpiece, the diameter of which is 12mm, is machining by intermittent ELID grinding use workpiece as dressing electrode, and after grinding the roughness Ra is 23.4nm.更多还原