横向交变载荷作用下三种涂层螺栓的防松性能

Anti-loosening Performance of Three Kind of Coated Bolts under Cyclic Transverse Load

选用二硫化钼涂层和碳化钨涂层对45钢螺栓进行表面处理,通过横向振动试验研究横向交变载荷作用下螺栓连接结构的松动行为,并与常用的电镀锌涂层螺栓进行对比分析,讨论3种涂层螺栓的防松性能。利用扫描电子显微镜和电子能谱仪分析试验后螺纹表面损伤形貌及化学成分,揭示螺纹表面的磨损机制。试验结果表明:二硫化钼涂层螺栓螺纹表面的主要磨损机制为疲劳磨损、磨粒磨损和氧化磨损,碳化钨涂层和电镀锌涂层螺栓螺纹表面的主要磨损机制为疲劳磨损和磨粒磨损;相同预紧力或等效应力条件下,二硫化钼涂层螺栓因其界面摩擦因数低,防松性能较差,碳化钨涂层螺栓因其表面耐磨性能优异,防松性能最好;相同预紧力矩条件下,二硫化钼涂层螺栓因预紧力高,防松性能最好,碳化钨涂层螺栓次之,电镀锌涂层螺栓最差。

MoS 2 and WC/C coatings were utilized to treat bolts made of 45 steel,the self-loosening behaviour of the two coated bolts were studied by lateral vibration test,and were compared with the Zinc coated bolts.The anti-loosening performance of three kind of coated bolts were discussed.The damage of the threads after tests was analyzed using scanning electron microscope(SEM)and energy dispersive X-ray(EDS),and the wear mechanisms between contact threads were revealed.It is found from test results that the main wear mechanisms of the contact surfaces between threads are delamination,abrasive wear and oxidation wear for the bolted joints coated with MoS 2 coatings,and those are delamination and abrasive wear for the WC/C and Zinc coated bolts.Under the same preload or equivalent stress at the thread root,the anti-loosening performance for the MoS 2 coated bolts is the worst due to the low friction coefficient,and that for the WC/C coated bolts is the best because of the excellent wear resistance.Under the same tightening torque,the anti-loosening performance for the MoS 2 coated bolts is the best due to the largest preload,the next is the WC/C coated bolts,and the last is the Zinc coated bolts.