材料期刊网

通过对商用X80管线钢进行适当的Cu合金化功能性改进,制备出不同Cu含量(1.06Cu、1.46Cu、2.00Cu,质量分数,%)的新型管线钢。利用抗菌性能检测、电化学测试、腐蚀产物分析、激光共聚焦显微镜(CLSM)等方法研究了含Cu管线钢的抗菌性能和微生物腐蚀行为。研究表明,含Cu管线钢对大肠杆菌和金黄色葡萄球菌均具有强烈的杀灭作用,以多边形铁素体为特征的1.0Cu管线钢能够保证在X80钢强韧性的水平下具有优异的抗微生物腐蚀性能。含Cu管线钢中富Cu相对抗微生物腐蚀性能起到了关键作用。1.0Cu钢和X80钢的线性极化电阻R_LPR在含有硫酸盐还原菌(SRB)的土壤浸出液中浸泡2 d后均急剧下降,导致X80钢的腐蚀电流密度明显大于1.0Cu钢。显微观察表明,大量生物膜的生成导致在SRB环境中的X80钢的点蚀数量和最大点蚀坑深度均高于1.0Cu钢。

Microbiologically influenced corrosion (MIC) is a major corrosion related problem for steel pipelines. The great loss caused by microbiologically influenced corrosion (MIC) on buried pipelines has been paid considerable attention domestically and internationally. Various physical, chemical or biological strategies have been used for MIC control, including biocides, coatings, cathodic protection and biocompetitive exclusion. These strategies have limitations of being expensive, subject to environmental restrictions, and sometimes inefficient. There is an urgent need for oil industry to develop environmentally friendly strategies for microbial corrosion control. Cu could play many benefical effects in steels, such as exerting a vigorous effect on hardenability, enhancing strength via precipitation strengthening, improving fatigue resistance, reducing susceptibility of hydrogen embrittlement, promoting formation protective layer etc.. Cu is well known for its inherent antimicrobial properties and is the focus of interest for potential application as a component in antibacterial materials. The Cu-bearing antibacterial stainless steel, characterized by continuous release of Cu ions with antibacterial function, provides analogy to develop a new type of MIC resistance pipeline steel. In this work, three different Cu contents (1.06Cu,1.46Cu,2.00Cu, mass fraction, %) pipeline steels, named 1.0Cu, 1.5Cu and 2.0Cu, were fabricated by making proper Cu alloying designs for X80 steel that currently used in oil/gas industry. Study on antibacterial performance and MIC behavior of novel Cu-bearing pipeline steels against Escherichiacoli (E.coli), Staphylococcusaureus (S.aureus) and Sulphate reducing bacteria (SRB) was carried out by antibacterial tests, electrochemistrical monitor, corrosion product analyses and confocal laser scanning microscope (CLSM). The results showed that Cu-bearing pipeline steels had strong antibacterial performance against E.coli and S.aureus compared with X80 steel. 1.0Cu steel with the microstructure of polygonal ferrite showed excellent resistance to SRB with remarkable strength enhancement by nano-scale Cu-rich precipitates and good impact toughness compared with X80 steel. Cu-rich precipitates in Cu-bearing pipeline steels were found to be responsible for the antibacterial capability. The linear polarization resistances (R_LPR) of both X80 and 1.0Cu steels in the soil-extract solution with SRB were dramatically decreased after 2 d, leading to the corrosion current density (i_corr) value of X80 steel was much higher than that of 1.0Cu steel. The corrosion product analysis results showed that much biofilm produced by SRB was the reason that many pits and larger pit depth on X80 steel than that of 1.0Cu steel.