摘要
由于铁路机车车辆在运行过程中经常出现螺栓连接的松动,螺栓疲劳断裂等导致螺栓连接性能下降的问题,影响行车安全。为了改善螺栓的安全性能,本文使用平均粒径55μm的高速工具钢球对常用的M12商用螺栓螺杆表面进行微粒子喷丸强化处理。测试了微粒子喷丸前、后螺栓扭矩系数以及螺栓轴向预紧力的下降情况和横向循环加载周次间的关系。结果表明,微粒子喷丸处理能够有效降低螺栓扭矩系数的分散程度,并减缓横向循环加载时轴向预紧力的下降。通过以上研究发现,微粒子喷丸处理后螺栓性能改善的原因可以主要归结于:(1)降低了约一倍的螺栓表面粗糙度;(2)螺栓表层硬度被提高了约20%;(3)在螺栓表层引入了大量额外的残余压应力。上述因素均在一定程度上降低了扭矩系数的分散性并提高了螺栓的疲劳强度。
Due to the loosening of bolt connection and the fatigue fracture of boltin the running process of railway rolling stock,the performance of bolts is often reduced,which affects the driving safety.In order to improve the safety performance of bolts,a high-speed tool steel ball with an average particle size of 55μm was used to strengthen the surface of the commonly used M12 commercial bolt.The relationship between the torque coefficient of bolt before and after micro-shot peening,the decline of bolt axial preload and transverse cyclic loading cycles was tested.The results show that the micro-shot peening can effectively reduce the dispersion degree of bolt torque coefficient and slow down the decline of axial preload during lateral cyclic loading.It can be found from the above research that the reasons for the improvement of bolt performance after micro-shotpeening can be mainly attributed to:①Reduced bolt surface roughness by about twice.②The surface hardness of the bolt has been increased by about 20%.③A large amount of additional residual compressive stress is introduced into the bolt surface.The above factors reduce the dispersion of torque coefficient and increase the fatigue strength of bolts to a certain extent.
作者
宋树亮
梁海啸
张远彬
常振
叶天一
SONG Shuliang;LIANG Haixiao;ZHANG Yuanbin;CHANG Zhen;YE Tianyi(CRRC QingdaoSifang Co.,Ltd.,Qingdao 266111,China)
出处
《机械》
2023年第11期38-45,共8页
Machinery
关键词
螺栓连接
微粒子喷丸
疲劳强度
扭矩系数
残余压应力
bolted joint
micro-shot peening
fatigue strength
torque coefficient
residual compressive stress
