Study on riboflavin accelerated SRB corrosion and low cycle fatigue failure of X80 pipeline steel
A variety of microbial species coexist in the soil where buried pipelines are in service,and the electron shuttles secreted by electricity-generating microorganisms may affect the corrosion behavior of microorganisms.Moreover,pipelines often experience low-frequency pressure fluctuations and long-term exposure to alternating loads,which can lead to low-cycle fatigue.Based on this,the influence of endogenous electron shuttles riboflavin on microbial corrosion fatigue was explored by studying the corrosion of X80 pipeline steel by sulfate-reducing bacteria.The results show that riboflavin promotes bacterial corrosion of metals by accelerating electron transfer,but does not change the corrosion products or process.Under the strain amplitude of 0.4%to 0.7%,the fatigue life of the two pre-corrosion systems relative to the non-corrosion system decreased by 17.5%to 27.8%and 33.5%to 58.1%,respectively.As the strain amplitude increases,the proportion of plastic strain amplitude in the total strain amplitude gradually increases.The cyclic response and Masing characteristics of the materials before and after corrosion remain unchanged.The prediction results of strain,strain energy density,and fatigue toughness life curves indicate that bacterial corrosion has a significant impact on the plastic strain life of steel,and fatigue fracture analysis verifies that bacterial corrosion accelerates the plastic failure of steel.