外加电位对X80管线钢近中性pH土壤应力腐蚀开裂行为的影响  

Influence of applied potential on stress corrosion cracking behavior of X80 pipeline steel in near-neutral pH soil environments

作　　者：赵新伟 张广利 张良 罗金恒 于美[2] 

机构地区：[1]中国石油集团石油管工程技术研究院CNPC石油管工程重点实验室,陕西西安710077 [2]北京航空航天大学材料科学与工程学院,北京100191

出　　处：《油气储运》2014年第11期1152-1158,共7页Oil & Gas Storage and Transportation

基　　金：中国石油天然气集团公司应用基础研究项目"高强度管道失效控制的应用基础研究";2011B-3308

摘　　要：在模拟近中性p H土壤腐蚀环境的NS4溶液中,采用慢应变速率拉伸(SSRT)试验、电化学极化和SEM观察,研究了外加阴极极化电位对X80管线钢近中性p H土壤应力腐蚀开裂(SCC)行为的影响。结果表明:X80管线钢在近中性p H土壤环境中SCC敏感性较高,开裂模式为穿晶SCC;SCC机制随外加阴极极化电位不同而改变,外加阴极极化电位高于-900 m V时,SCC受阳极溶解和氢脆混合控制,外加阴极极化电位低于-900 m V时,SCC为氢脆控制;随着外加电位负向增加,慢拉伸试样的断面收缩率、延伸率和断裂时间降低,SCC敏感性增加,在实际管道阴极保护工程中要避免过保护。Using slow strain rate tension （SSRT） experiment, electrochemical polarization and SEM observation, the influence of applied cathodic polarization potential on stress corrosion cracking （SCC） behavior of X80 pipeline steel is analyzed in a simulated near-neutral pH soil environment of NS4 solution. The results show that the SCC sensitivity of X80 pipeline steel is higher in near-neutral pH soil environments, and the cracking model is transgranular SCC. SCC mechanism changes with different applied cathodic polarization potential - when the applied cathodic polarization potential is higher than -900 mV, SCC is controlled jointly by anodic dissolution and hydrogen embrittlement, and when the applied cathodic polarization potential is under -900 mV, SCC is controlled by hydrogen embrittlement. With the increase of negative applied potential, section shrinkage, elongation, and fracture time of slow tension specimen are reduced, and the SCC sensitivity increases, so it is necessary to avoid over-protection in actual pipeline cathodic protection.

关 键 词：X80管线钢 近中性土壤环境 应力腐蚀开裂(SCC) 外加电位 

分 类 号：TG172.4[金属学及工艺—金属表面处理]