Cr含量对X120级管线钢组织及耐酸性腐蚀性能的影响  

Influence of Cr Content on Microstructures and Acid Corrosion Properties of X120Grade Pipeline Steel

作　　者：武会宾[1] 刘跃庭[1] 王立东[1] 刘立甫[1] 

机构地区：[1]北京科技大学高效轧制国家工程研究中心,北京100083

出　　处：《材料工程》2013年第9期32-37,43,共7页Journal of Materials Engineering

基　　金：国家科技重大专项(2011ZX05016-004)

摘　　要：运用SEM,TEM和失重法研究了Cr元素对X120级管线钢力学性能及耐CO2/H2S腐蚀性能的影响。力学性能结果表明:四种实验钢显微组织均为回火马氏体,力学性能均达到API 5L标准中X120级别,且随Cr含量增加,板条束数量增加,宽度变窄,使得屈服强度和抗拉强度逐渐增大;钢中析出物主要为(Nb,Ti)(C,N),当Cr含量达到3%(质量分数)时,析出物中发现极少量Cr。腐蚀实验结果表明:在CO2/H2S环境下,四种钢腐蚀产物膜均分为两层,内层主要为CO2腐蚀产物FeCO3,外层是FeS;Cr主要存在于腐蚀产物膜的内层,且随钢中Cr含量的增加,Cr在内层腐蚀产物中的富集量加大;钢中的Cr元素使腐蚀产物膜变得致密且具有离子选择性,阻止腐蚀液中的阴离子到达基体,进而提高钢的耐CO2/H2S腐蚀性能。Effects of Cr on microstructures and acid corrosion properties of X120 grade pipeline steel were studied with SEM and TEM and mass loss. The mechanical properties results show that the mi- crostructures of four tested steels are all tempered martensites, and the mechanical properties are all up to X120 grade. Yield strength and tensile strength of the four tested steels are improved with the increasing of Cr content. The precipitated phases of tested steels are （Nb, Ti） （C, N）. Precipitation of Cr is little, and was only discovered in the 3Cr steel through the experiment. The corrosion experi ment results indicate that the corrosion scales on the four tested steels have two layers structure under the condition of CO2/H2S. The outer layer is mainly containing FeS, the inner layer FeCO3. Cr enri ches in the inner layer, and the content increases with the increasing of Cr element in matrix. The Cr- rich enhances the compactness of the corrosion scales, and the scales have ion-passing-selectivity, which hinders the moving of anion to matrix, and finally the resistance to CO2/H2S corrosion increa- ses.

关 键 词：CR含量 X120 CO2/H2S腐蚀 Cr富集 离子选择性 

分 类 号：TG172.3[金属学及工艺—金属表面处理]