Cr含量对油气管道37Mn5钢在模拟CO2溶液中腐蚀行为的影响

Influence of Cr Content on Corrosion Behavior of Oil-Gas Pipeline 37Mn5 Steel in Simulated CO Solution

为了提高油气管道37Mn5钢在CO2溶液中的防腐蚀性能,通过添加Cr元素和热处理的方式改善其组织和腐蚀行为,并进行了高温高压CO2腐蚀模拟试验测试。结果表明:2%Cr与6%Cr含量37Mn5钢由回火索氏体构成,10%Cr含量37Mn5钢中主要存在马氏体组织。2%Cr含量37Mn5钢相对6%Cr与10%Cr具备更大的腐蚀速率,热处理使2%Cr含量37Mn5钢的耐蚀性明显改变。10%Cr含量37Mn5钢腐蚀产物上形成了部分晶体颗粒,其形态和FeS化合物较为接近。2%Cr与6%Cr含量37Mn5钢的腐蚀产物内存在S、Fe、O3种元素,S在外部区域的腐蚀产物中含量较高。2%Cr与6%Cr含量37Mn5钢的外层腐蚀产物中都存在FeS。10%Cr含量的表面组织中存在少量FeS。6%Cr含量更易实现Cr富集的过程,形成了S比例很高的腐蚀产物。10%Cr含量37Mn5钢经过腐蚀后形成了单层膜的组织结构,S含量较少,几乎未发生腐蚀。

For improving the corrosion resistance of oil-gas pipeline 37Mn5 steel in CO2 solution,the structure and corrosion behavior were improved by adding Cr element and heat treatment,and the high-temperature and high-pressure CO2 corrosion simulation was carried out by corrosion experimental test.Results showed that 37Mn5 steel containing 2%Cr and 37Mn5 steel containing 6%Cr were composed of tempered sostenite,and 37Mn5 steel containing 10%Cr mainly composed of martensite.The corrosion rate of 37Mn5 steel containing 2%Cr was higher than those of 37Mn5 steel containing 6%Cr and 10%Cr,and the corrosion resistance of 37Mn5 steel containing 2%Cr was significantly changed during the heat treatment process.Additionally,some crystal particles formed on the corrosion products of 37Mn5 steel containing 10%Cr,whose morphology was close to that of FeS compound.Three elements S,Fe and O existed in the corrosion products of 37Mn5 steel with Cr content of 2% and Cr content of 6%,and the amount of S element rose in the corrosion products in the outer regions.Moreover,FeS existed in the corrosion products of 37Mn5 steel with 2% Cr and 6% Cr.A small amount of FeS was found in surface tissues containing 10%Cr.Owing to easier Cr enrichment,the corrosion products with high S ratio formed at steel with 6%Cr.Furthermore,37Mn5 steel with 10%Cr formed the structure of monolayer after corrosion,which possessed less S content,and almost no corrosion was observed.