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探讨了C/SiC陶瓷基复合材料螺纹紧固件在室温下的拧紧特性。试验测试了紧固件在拧紧和拧松过程中,力矩与预紧力两者的对应关系,记录了预紧力在短时、长时内的减小比率,并用显微镜观察了螺纹面的磨损情况。另外,分析了材料非线性拉伸行为对拧紧状态所造成的影响。结果表明:拧紧、拧松力矩与预紧力之间近似呈线性关系,螺纹面和支承面的平均摩擦系数分别为0.52和0.46;随拧紧力矩增大,螺纹面产生一定程度磨损,螺纹之间的相互嵌入作用减弱,因此预紧力在拧紧后的降幅减小,稳定性提高;对螺栓进行适当的预拉伸处理,提高材料的弹性极限后,可提高紧固件的抗松弛能力。
The tightening characteristics of C / SiC ceramic matrix composite threaded fasteners at room temperature were discussed. Test the fastener in the process of tightening and loosening, the relationship between torque and preload, the pre-tightening force in the record short-term, long-term reduction ratio, and the use of a microscope to observe the wear of the thread surface Happening. In addition, the influence of non-linear tensile behavior on the tightening state was analyzed. The results show that there is an approximate linear relationship between tightening torque, unscrewing torque and pre-tightening force. The average friction coefficient between screw thread and bearing surface is 0.52 and 0.46, respectively. With the increase of tightening torque, Of the embedding effect weakened, so the reduction in preload tightening after the decrease, improve the stability of the bolt pre-tensile treatment to improve the elastic limit of the material, can improve the anti-sagging ability of fasteners.