腐蚀对5.8级环槽铆钉疲劳性能影响的研究

STUDY ON THE INFLUENCE OF CORROSION ON FATIGUE PROPERTIES OF THE 5.8-GRADE LOCK BOLT

  • 摘要: 为研究腐蚀对环槽铆钉剪切疲劳性能的影响,对5.8级LMY8环槽铆钉与同规格普通螺栓进行剪切疲劳试验、90天盐雾腐蚀处理后的剪切疲劳试验,并对腐蚀处理后的环槽铆钉进行表面形貌分析、能量色散X射线光谱(EDX)分析和断口形貌分析。结果表明:由于套环和铆钉杆之间的过盈配合,使得环槽铆钉具有较好的抗腐蚀性能,腐蚀处理后环槽铆钉的疲劳寿命仅下降6.57%,相比经过腐蚀处理的螺栓疲劳寿命下降了74.47%。腐蚀处理后的环槽铆钉的光杆段腐蚀程度较轻,但光杆段表面出现较多腐蚀坑,这将影响环槽铆钉的力学性能;腐蚀处理后环槽铆钉的疲劳断口在疲劳源区、裂纹扩展区和瞬断区均发生变化,主要原因是铆钉杆的腐蚀坑使得疲劳过程表现出更明显的脆性,因此未作腐蚀处理的环槽铆钉可以观察到剪切唇,而经腐蚀处理的环槽铆钉断口较平整。

     

    Abstract: In order to study the effect of corrosion on the shear fatigue properties of lock bolts, Shear fatigue tests have been conducted on 5.8-grade LMY8 lock bolts and bolts of the same specification before and after 90 days of salt spray corrosion treatment. And performed on the corrosive lock bolts are surface morphology analysis, energy dispersive X-ray spectroscopic (EDX) analysis, and fracture morphology analysis. The results show that: due to the interference fit between the collar and the lock bolt rod, the lock bolt has good corrosion resistance, the fatigue life of the lock bolts after corrosion is only reduced by 6.57% lower than that of the corrosion treated bolts by 74.47%. The corrosion degree of the polished rod of the lock bolt after corrosion is light, but there are many corrosion pits, which will affect the mechanical properties of the lock bolt. The fatigue fracture of the lock bolt after corrosion changes in the fatigue source, propagation, and transient breaking area, and the main reason is that the corrosion pit of the lock bolt rod makes the fatigue process exhibit more obvious brittleness. Therefore, shear lip can be observed for uncorroded lock bolts, while it is not observed for corroded lock bolts.

     

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