石油化工管线钢的热处理与耐蚀性能研究

Study on Heat Treatment and Corrosion Resistance of Petrochemical Pipeline Steel

采用X射线衍射分析仪（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）等分析方法,对三元复合驱采油30Cr13管线钢回火过程中的组织转变和析出相演变进行了分析,并利用动电位极化方法研究了不同回火温度下30Cr13管线钢的耐腐蚀性能。结果表明：300℃和500℃回火管线钢基体组织都为回火马氏体,但是后者的马氏体内部有一定含量的孪晶结构。650℃回火管线钢基体组织为块状铁素体;300℃回火管线钢中的析出物为M3C型碳化物,其Cr含量与基体相当,而500℃和650℃回火管线钢中的析出物为M（23）C6碳化物,都为富Cr型碳化物;回火温度为500℃的管线钢出现了＂失钝＂现象,造成其耐腐蚀性能明显低于回火温度为300℃和650℃的管线钢,650℃回火条件下淬火温度的提高并不能显著改善管线钢的耐点蚀性能。

The microstructure transformation and precipitates evolution of ternary compound oil drive 30 Cr13 pipeline steel during tempering were analyzed by X ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM） etc, and the corrosion resistance of 30 Cr13 pipeline steel at different tempering temperatures was studied by potentiodynamic polarization method. The results show that, the microstructure of pipeline steel tempered at 300 ℃ and500 ℃ is tempering martensite, but there is certain content of twin structure in latter martensite, the microstructure of pipeline steel matrix tempered at 650 ℃ is block ferrite. The precipitate in pipeline steel tempered at 300 ℃ is M3 C carbide, the content of Cr is equal to that of the matrix, and the precipitates of pipeline steel tempered at 500 ℃ and 650 ℃ are M（23）C6 carbides, all of which are Cr rich carbides. The corrosion resistance of the pipeline steel tempered at 500 ℃ is significantly lower than that tempered at 300 ℃ and 600 ℃ due to the ＂blunt＂ phenomenon, and the increase of quenching temperature of the pipeline tempered at 650 ℃ can not significantly improve the pitting corrosion resistance of pipeline steel.