M24高强螺栓腐蚀后力学行为研究

Mechanical Property Degradation after Corrosion of M24 High Strength Bolts

对浸油和无浸油处理的M24高强螺栓腐蚀后的力学性能展开了试验研究。基于中性盐雾腐蚀试验研究了不同腐蚀时间下螺栓腐蚀产物的宏观形貌变化,发现锈层厚度、螺栓表面粗糙度随腐蚀时间逐渐增大,无浸油螺栓在腐蚀初期比浸油螺栓腐蚀情况严重,而在腐蚀后期表面形貌基本一致,建立了浸油和不浸油螺栓腐蚀时间与质量损失的定量关系。基于腐蚀后的静力拉伸试验,发现螺栓刚度基本随腐蚀程度的增大线性下降,建立了两种螺栓的刚度退化公式;获取了不同腐蚀程度下浸油和不浸油高强螺栓的荷载位移曲线,发现随腐蚀时间的增长,二者的屈服强度、极限抗拉强度下降明显,但对伸长率、断面收缩率的影响较小。

In order to study the mechanical property degradation after corrosion, corrosion and mechanical tests were conducted on the M24 high strength bolts, which were treated with and without oil immersion. On the basis of neutral salt spray corrosion test, macro morphology of bolt corrosion products with different corrosion time was observed. It was found that the thickness of rust layer and the surface roughness of bolt increase with corrosion time. The corrosion of oil-free bolt was more serious than that of oil-immersed bolt in the early stage of corrosion, but the surface morphology was basically the same in the later stage of corrosion. Besides, the relationships of the two kinds of bolt between mass loss and corrosion time were stablish. On the basis of static tensile tests, it was found that the stiffness of bolt decreased gradually with the increase of corrosion degree. The stiffness degeneration formula was regressed. In addition, the load-displacement curves of oil-immersed and oil-free bolt were obtained at different corrosion time. With the increase of accelerated corrosion time, the yield strength and ultimate strength were found to have distinct decrease trends, but the elongation and area reduction were hardly influenced.