HXD1C机车电机与抱轴箱连接螺栓断裂研究分析

发布时间：2018-07-05 16:18

本文选题：高强度螺栓 + 断裂　；参考：《湖南大学》2012年硕士论文

【摘要】：由于螺栓断裂问题在工程应用中普遍存在,对社会生产和财产、人身安全危害巨大。本文针对HXD1C机车转向架驱动单元抱轴箱与电机连接的10.9级高强度螺栓在装配后机车出厂前发生批量断裂问题,以螺栓为研究对象,通过对螺栓的受力、装配尺寸、装配工艺分析,并采用理化检测方法对断裂螺栓进行进一步分析,发现了螺栓断裂的原因。采取改进螺栓设计和螺栓工艺等措施,保证螺栓的正常工作和机车的正常安全运行。本文的主要研究结果如下： (1)通过对抱轴箱和电机的接口尺寸和抱轴箱、电机装配过程的分析,排除了因为零部件不合理的设计和装配工艺而导致螺栓的异常受力而遭到破坏这一原因。同时也通过螺栓的扭矩试验、破坏扭矩实验、液压扳手的校核,证明了在螺栓装配过程中的装配操作符合操作规范要求。 (2)对螺栓采用断口分析方法,发现螺栓断口呈现脆性断裂特征,并根据螺栓断裂一般发生在安装后一段时间这一延迟断裂的特点,初步确定了螺栓属于氢脆断裂。 (3)采用化学成分分析、力学性能试验等测试表明：螺栓的原材料以及该批螺栓的材质和热处理状态尚好；通过金相检测发现裂纹由细小腐蚀坑坑底萌生,腐蚀坑坑底的灰色物可能为发黑时产生的氧化层。从而推断细小腐蚀坑在发黑之前已产生。因此,螺栓在制造过程中曾发生过度酸洗,使螺栓的螺杆与其六角头连接处(R角过渡处)表面产生细小腐蚀坑,从而引起螺栓表面吸氢；同时,螺栓安装后在其螺杆与其六角头连接处(R角过渡处)存在较大应力集中,促使螺栓发生氢致延迟断裂。 (4)通过对螺栓断裂前后不同工艺的比较,找到了最终使螺栓产生氢致延迟断裂的工艺原因。因为螺栓的用料直径减小以减少磨削加工次数,从而导致了螺栓的过渡圆角半径过小,在此圆角处产生应力集中。最后对生产工艺进行了改进,新工艺主要是：增大了过渡圆角半径,并增加了去氢处理工艺。采用新工艺生产的螺栓安装在机车上后未出现类似断裂情况,保障了机车的正常运行。从而彻底解决了螺栓的断裂问题。
[Abstract]:Because the bolt fracture problem is common in the engineering application, it has great harm to the social production and property and the personal safety. In this paper, the 10.9 grade high strength bolt which is connected with the motor in the driving unit of the HXD1C locomotive bogie drive unit has the problem of mass fracture before the locomotive is out of the factory. The bolt is the research object and the force of the bolt is taken as the research object. In order to ensure the normal work of the bolt and the normal operation of the locomotive, the main results of this paper are as follows: the main research results are as follows:
(1) through the analysis of the interface size of the axle box and the motor and the assembly process of the spindle box and the motor, the cause of the abnormal stress caused by the bolt is eliminated because of the unreasonable design and assembly process of the parts. At the same time, the bolt torque test, the failure torque experiment and the checking of the hydraulic wrench have proved that the bolt is in the bolt. The assembly process in the assembly process meets the requirements of operation specification.
(2) the fracture analysis method of bolt is used to find the characteristics of the brittle fracture of the bolt fracture, and the bolt fracture is usually characterized by the delayed fracture for a period of time after installation, and it is preliminarily determined that the bolt is a hydrogen embrittlement fracture.
(3) the results of chemical composition analysis and mechanical properties test show that the raw material of bolt and the heat treatment state of the bolt are good, and the cracks are germinating from the bottom of the small corrosion pit through the metallographic examination, and the gray matter at the bottom of the corrosion pit may be produced by the oxidation layer produced when the black pit is blackened. It has been produced before. Therefore, the bolt has been excessively pickled during the manufacturing process, making the bolt screw and its six corner joint (the R corner transition) produce a small corrosion pit, thus causing the bolt surface hydrogen absorption; at the same time, the bolt is installed at the connection of its screw and its six corner head (the transition of the corner of the corner of the R) after the bolt is installed, to promote the bolt. Hydrogen induced delayed fracture occurred.
(4) through the comparison of the different processes before and after the bolt fracture, the technological cause of the delayed fracture of hydrogen induced by the bolt was found, because the diameter of the bolt was reduced to reduce the grinding processing times, and the transition radius of the bolt was too small and the stress concentration was produced at the corner. Finally, the production process was improved. The new technology is mainly: increasing the radius of the transition angle and increasing the dehydrogenation process. The bolt is installed on the locomotive without a similar fracture condition, which ensures the normal operation of the locomotive. Thus the bolt fracture problem is completely solved.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：U260.331.7;TH131.3

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