【作者】 郭天官；

【导师】 张友坤； 石宝英；

【作者基本信息】 吉林大学 ， 车辆工程， 2011， 硕士

【摘要】 汽车变速器零件(材料20CrMnTi)热处理以后的加工主要是磨削。磨削时,由于磨削温度高,在磨削表面层形成较大的热应力,有时会出现磨削裂纹。这些磨削裂纹会降低零件的使用寿命,或者造成零件报废。本文就端面磨削裂纹的产生原因和消除裂纹的措施进行探讨。本文就端面磨削裂纹的产生原因和消除裂纹的措施进行探讨。本文研究的目的是通过对磨削原理以及磨削过程和磨削表面残留应力关系的数学模型进行研究,找出对磨削应力产生作用的因素。然后从零件内应力、毛坯正火方法、零件热处理方法、磨削热和磨削温度的控制、零件磨削加工条件几个方面对磨削裂纹产生的原因进行分析,进而通过从毛坯正火、零件热处理、磨削加工条件几个方面采取措施,控制磨削裂纹的产生。磨削裂纹与磨削过程中的磨削力和磨削温度有关,因此消除磨削裂纹的根本措施是降低磨削温度、降低磨削力和消除零件内应力。在热处理正火工艺方面,零件等温正火替代常规正火,得到均匀的平衡组织,为最终处理提供了良好的组织准备,使最终热处理变形更小,变形规律性更强。在热处理渗碳淬火工艺方面,控制齿轮表面碳浓度、控制工件渗碳后冷却速度、控制奥氏体晶粒度、降低残留奥氏体的数量、消除或降低内应力、可控气源的选择、冷却介质的选择。在磨削加工工艺方面,选用合适的砂轮、选用合适的切削液、选择合理的磨削参数、合理选用砂轮修整工具、磨削表面进行强力喷丸处理。通过采取以上措施,最终达到消除零件磨削裂纹的目的。零件正火、渗碳淬火质量是控制磨削裂纹的基础;树脂结合剂砂轮的使用对消除端面磨削裂纹起到了非常关键的作用;良好的冷却效果是防止零件磨削裂纹的根本保证;进行不断的工艺改进,保证合理的磨削加工参数;砂轮修整质量的好坏也是一个重要因素;要有好的磨削裂纹检查手段。吸收他人的研究成果,结合自己的工作实践,探索消除零件磨削裂纹的方法,为控制零件磨削裂纹提供一个比较全面的、可以供大家借鉴的解决方法。消除磨削裂纹对于提高产品质量、降低废品损失、提升产品的竞争力具有现实意义。更多还原

【Abstract】 Automotive Transmission Parts (Material 20CrMnTi) after the heat treatment process is mainly within grinding. Grinding, due to the high grinding temperature in the grinding surface layer to form a larger thermal stress, and sometimes grinding cracks will appear. These grinding cracks will reduce the life of components, or cause parts scrapped. This article face grinding cracks on the causes and discuss measures to eliminate cracks.This paper will end the causes and grinding crack the measures to eliminate crack were discussed.The purpose of this study is based on the principle and grinding process and grinding grinding surface residual stress studied mathematics model of the relationship between stress of grinding, find out the factors effect. Then from stress, casting parts are fire method, heat-treatment method, grinding heat and grinding temperature control, parts of grinding conditions aspects of the grinding the causes of cracks are analyzed, and then from blank is fire, by grinding conditions heat-treatment, several aspects take measures to control grinding the fatigue.In the process of grinding cracks and grinding grinding force and grinding temperature related, so the fundamental measures to eliminate grinding crack is to reduce grinding temperature, reduce internal grinding force and eliminate parts.In the heat treatment is fire process, and conventional isothermal normalizing replacement parts are fire, get evenly balanced organization, for final processing provides good organization preparation, the final heat treatment deformation smaller, deformation regularity stronger. In the heat treatment carburizing aspects, control gear surface carbon concentration, control workpiece cooling speed, carburizing control austenitic grain degrees, reduce the number of residual austenite, eliminate or reduce stress, controlled source selection, cooling medium choice. In grinding machining process, and the grinding wheel, appropriate choice of appropriate cutting fluids, the rational choice of grinding parameters, the reasonable choice of grinding wheel dressing tools, grinding surface powerful shot peening treatment. Through adopts the above measures, and finally reach the purpose of eliminating parts grinding crack. Parts are fire, carburizing quench quality is the basis of grinding crack control; Resin-bonded grinding wheel to eliminate the use of face grinding crack plays a key role; Good cooling effect is to prevent parts the fundamental guarantee of grinding crack; For continuous process improvement, guarantee reasonable grinding machining parameters; The stand or fall of grinding wheel dressing quality is one of the important factors; To have a good grinding crack inspection method.Absorb others research results, with his work practice, to explore the method to eliminate parts grinding crack for control parts, provide a comprehensive grinding crack, for everybody reference solution.Eliminate grinding crack to enhance quality, reduce scrap loss, improve the competitiveness of their products have realistic meanings.更多还原