海水腐蚀环境下高强度钢腐蚀疲劳裂纹扩展行为研究  

Study on corrosion fatigue crack growth of high strength steel under the seawater corrosive environment

作　　者：罗霞飞 石健[1] 邵永波[2] 高旭东 郭永健 钟颖 LUO Xiafei;SHI Jian;SHAO Yongbo;GAO Xudong;GUO Yongjian;ZHONG Ying(School of Mechanical Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China;School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]西南石油大学机电工程学院,四川成都610500 [2]西南石油大学土木工程与测绘学院,四川成都610500

出　　处：《中国海上油气》2023年第4期181-188,共8页China Offshore Oil and Gas

摘　　要：海洋平台在海水腐蚀和海浪流等循环载荷的耦合作用下极易发生腐蚀疲劳断裂。采用自主设计的海水间歇供水循环系统模拟干湿比为1∶1的海水干湿交替环境,研究了空气环境、全浸环境、干湿交替环境和应力比0.1、0.3和0.5对高强度钢EH690钢疲劳裂纹扩展的影响。基于试验获得的a-N曲线和da/dN-ΔK曲线,发现在裂纹扩展前期,EH690钢在干湿交替环境与全浸环境中的裂纹扩展速率为空气中的3倍左右,呈现出显著的疲劳裂纹扩展加速现象;对于给定的应力强度因子,疲劳裂纹扩展速率随着应力比的增大而增大;拟合得到不同环境和应力比下CT试件的Pairs常数;通过扫描电镜从微观角度分析EH690高强钢的腐蚀疲劳裂纹扩展机理。本文研究结果为实际海洋平台的腐蚀疲劳寿命评估提供了可靠的试验数据参考。The offshore platforms are prone to corrosion fatigue fracture especially under the cyclic loads of ocean waves and currents combined with corrosion environment.The self-designed seawater intermittent water supply circulation system was used to simulate the alternating dry and wet environment of seawater with a dry-wet ratio of 1:1,and the effects of air,full immersion,alternating dry-wet environments and stress ratio of 0.1,0.3 and 0.5 on fatigue crack growth of EH690 high-strength steel were investigated.Based on the a-N curve and da/dN-ΔK curve obtained from the fatigue test,it is found that the fatigue crack growth rate of EH690 steel in the alternating dry and wet environment and the full immersion environment in the early stage of crack growth is about 3 times that of the air,showing a significant fatigue crack propagation acceleration phenomenon.For a given stress intensity factor,the corrosion fatigue growth rate increases with the increase of stress ratio.The Paris constants of CT specimens were obtained by fitting the experimental data under different environments and stress ratios.The corrosion fatigue crack propagation mechanism of EH690 high-strength steel was also analyzed in microstructure scale by scanning electron microscopy.The results of this work provide a reliable experimental data reference for the prediction of corrosion fatigue life of actual offshore platform.

关 键 词：EH690高强度钢 腐蚀疲劳裂纹扩展 海水干湿交替环境 应力比 微观断貌 

分 类 号：TG172.5[金属学及工艺—金属表面处理]