超高频感应钎焊单层超硬磨料成形砂轮研制

发布时间：2018-04-05 11:11

本文选题：成形砂轮　切入点：温度分布　出处：《南京航空航天大学》2015年硕士论文

【摘要】：单层钎焊超硬磨料砂轮具有磨粒把持强度高、砂轮寿命长以及磨削效率高等优势,在高效磨削中体现出较好的效果,是未来高速高效磨削的重要工具。然而,由于高温钎焊的热过程影响,钎焊超硬磨料砂轮基体的变形严重问题是限制该类砂轮制造技术进一步发展的关键问题。目前,通过采用局部超高频感应加热方法,已可有效改善形面简单的平行砂轮常用的整体加热方法所存在的基体热变形问题,满足了精密磨削需求。但是,该方法还不能应用于工作形面较复杂的成形砂轮制造,还未解决成形砂轮感应加热时存在的形面温度分布不均匀问题,从而限制了钎焊超硬磨料成型砂轮制造质量的提高。针对成形砂轮超高频感应加热时存在的形面温度分布不均匀问题,本文提出将复杂形面简化为其构成要素(凹、凸特征成形面)进行研究,分析不同感应器结构对特征成形面温度分布的影响规律,进而优化设计燕尾槽型成形砂轮钎焊用感应器结构,以实现成形面温度的均匀分布。本文完成的主要研究工作如下:1、将成形砂轮工作曲面简化为凹、凸两类特征成形面进行研究,借助有限元仿真软件,重点分析了不同线圈夹角和导磁体磁轭尺寸对凹面特征成形面温度分布的影响,以及不同线圈结构和线圈夹角对凸面特征成形面温度分布的影响,在提高凹面加热效率的同时降低了凸面加热效率,为燕尾槽型成形砂轮超高频感应钎焊用感应器结构的优化设计提供了数据基础。2、基于以上对特征成形面温度场的研究,重点分析了导磁体长度对成形面温度分布的影响规律,对燕尾槽型成形砂轮钎焊用感应器结构进行了优化设计。采用结构优化的感应器结合超高频连续感应钎焊工艺研制了单层钎焊CBN成形砂轮,并对焊后砂轮表面形貌以及热变形情况进行评价。结果表明,焊后砂轮表面磨粒仍为有序排布,形面各处钎料分布均匀,无钎料堆积和氧化现象;焊后砂轮基体变形量在13μm以内,可以达到未经历加热过程的电镀CBN砂轮的同等精度。3、采用研制的单层钎焊CBN成形砂轮高效成形磨削TC4钛合金试件,分别从磨削力、磨削温度、试件加工表面尺寸精度和轮廓精度、试件加工表面完整性以及砂轮磨损情况综合评价钎焊砂轮的磨削性能。结果表明,不同磨削用量条件下,磨削力比和磨削温度低,砂轮锋利度高;钛合金试件加工表面尺寸和轮廓精度均满足设计要求;砂轮主要磨损形式为磨耗磨损,未出现磨粒整体破碎或整颗剥落现象,砂轮可以长期保持稳定和优异的磨削性能。
[Abstract]:Single layer brazed super hard abrasive grinding wheel has the advantages of high abrasive holding strength, long grinding wheel life and high grinding efficiency, which is an important tool for high speed and high efficiency grinding in the future.However, due to the thermal process of high temperature brazing, the serious deformation of the matrix of brazed superhard abrasive grinding wheel is the key problem to limit the further development of this kind of grinding wheel manufacturing technology.At present, by adopting the local ultra-high frequency induction heating method, the thermal deformation of the matrix in the common integral heating method of the simple parallel grinding wheel can be effectively improved, and the precision grinding needs can be satisfied.However, the method can not be applied to the manufacturing of the forming wheel with more complicated working surface, and the problem of uneven temperature distribution of the shape surface in the induction heating of the shaped grinding wheel has not been solved.Therefore, the improvement of manufacturing quality of brazing superhard abrasive grinding wheel is limited.In order to solve the problem of uneven temperature distribution in the shape surface of forming grinding wheel during ultra-high frequency induction heating, this paper proposes to simplify the complex shape surface into its constituent elements (concave and convex characteristic forming surface).The influence of different inductor structures on the temperature distribution of characteristic forming surface is analyzed, and the inductor structure for brazing of swallowtail groove shaped grinding wheel is optimized, so as to realize the uniform distribution of forming surface temperature.The main research work accomplished in this paper is as follows: 1. The working surface of the grinding wheel is simplified to concave and convex forming surfaces, and the finite element simulation software is used.The influence of different coil angle and magnetic yoke size on the temperature distribution of concave characteristic forming surface, and the influence of different coil structure and coil angle on the temperature distribution of convex surface characteristic forming surface are analyzed.The heating efficiency of concave surface is improved and the heating efficiency of convex surface is reduced, which provides a data basis for optimizing the structure of induction brazing inductor used in ultra-high frequency induction brazing of swallowtail groove shaped grinding wheel. 2. Based on the above research on temperature field of characteristic forming surface,The influence of the length of magnetic conductors on the temperature distribution of the forming surface is analyzed, and the structure of the inductor used in the brazing of swallowtail groove shaped grinding wheel is optimized.A single-layer brazed CBN grinding wheel was developed by using a structural optimization inductor combined with ultra-high frequency continuous induction brazing process. The surface morphology and hot deformation of the wheel were evaluated after welding.The results show that after welding, the abrasive particles on the surface of the grinding wheel are still arranged in an orderly manner, the solder distribution is uniform and there is no accumulation and oxidation of the filler metal, and the deformation of the matrix of the grinding wheel is less than 13 渭 m after welding.The same precision of electroplated CBN grinding wheel without heating process can be achieved. The single-layer brazed CBN shaped grinding wheel is used to efficiently form and grinding TC4 titanium alloy specimen, respectively from grinding force, grinding temperature, grinding temperature, grinding temperature, grinding temperature, grinding temperature, grinding temperature, grinding temperature, grinding temperature and grinding temperature.The grinding performance of brazed grinding wheel is evaluated synthetically by surface dimension precision and contour precision of specimen machining surface integrity of specimen and wear of grinding wheel.The results show that the grinding force ratio and temperature are low, the sharpness of grinding wheel is high, the machining surface size and contour precision of titanium alloy specimen meet the design requirements, the main wear form of grinding wheel is wear and tear.The grinding wheel can maintain stable and excellent grinding performance for a long time.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG743

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