X80管线钢焊接接头的组织对其超临界CO_(2)腐蚀行为的影响  

Effect of Microstructure of Welded Joint of X80 pipeline Steel on Its Corrosion Behaviors in Supercritical CO_(2)

作　　者：姚彬 高秋英[1] 张超[1] 严永博 邓洪达[2] 兰伟[2] YAO Bin;GAO Qiuying;ZHANG Chao;YAN Yongbo;DENG Hongda;LAN Wei(Northwest Oil Field Branch Company,Sinopec,Urumqi 830011,China;Chongqing University of Science and Technology,Chongqing 401331,China)

机构地区：[1]中国石油化工股份有限公司西北油田分公司,乌鲁木齐830011 [2]重庆科技学院,重庆401331

出　　处：《腐蚀与防护》2022年第8期36-41,共6页Corrosion & Protection

基　　金：中石化重点科研项目(319016-5);重庆科技学院校内科研基金资助项目(CK2016Z09);重庆市自然科学基金项目(cstc2019jcyj-msxmX0181)。

摘　　要：研究了X80管线钢焊接接头组织对其超临界CO_(2)腐蚀行为的影响。采用金相显微镜观察高温回火后X80管线钢焊接接头的不同区域(基材区、细晶热影响区、粗晶热影响区和焊缝区)的组织特征。采用扫描电镜(SEM)观察该焊接接头不同区域在含饱和水的超临界CO_(2)(40℃,10 MPa)气相环境中腐蚀后的形貌,并采用X射线衍射仪(XRD)分析腐蚀产物物相。结果表明:基材区和焊缝区主要由多种形式铁素体构成;细晶热影响区和粗晶热影响区组织为多种形式铁素体和珠光体;在含饱和水的超临界CO_(2)环境中焊接接头各区域都发生明显的CO_(2)腐蚀,花型碳酸亚铁腐蚀产物岛分散在致密腐蚀产物表面,且腐蚀产物膜下出现腐蚀坑;基材区、焊缝区、粗晶热影响区的M-A岛主要在晶界析出,故膜下局部腐蚀严重,而细晶热影响区的M-A岛在晶体内弥散析出且晶粒细小,故膜下局部腐蚀轻微。The effect of microstructure of X80 pipeline steel welded joint on its corrosion behavior in supercritical carbon dioxide(SC-CO_(2)) environment was studied. The microstructure of base metal(BM), fine grain heat affected zone(FGHAZ), coarse grain heat affected zone(CGHAZ), and welding metal(WM) of X80 pipeline steel welded joint after high temperature tempering were observed by metallurgical microscopy. The corrosion morphology of different zones in the welded joint corroded in gas phase environment of SC-CO_(2)containing saturated water under condition of 40 ℃ and 10 MPa were observed by scanning electron microscopy(SEM), and the phase composition of the corrosion scale was analyzed by X-ray diffraction(XRD). The results show that the BM and WM consisted of different forms of ferrites. The microstructure of FGHAZ and CGHAZ were different forms of ferrites and pearlites. CO_(2)corrosion could be found in all zones of the welded joint obviously in SC-CO_(2)environment containing saturated water, and flowerlike iron carbonate corrosion scale islands dispersed on the surface of dense corrosion scale. Corrosion pits under the corrosion scale appeared at all zones. Localized corrosion under scale was heavy at BM, WM, CGHAZ due to Martensite-austenite(M-A) islands precipitating at grain boundaries, while it was slight at FGHAZ due to the dispersive precipitation of M-A islands in grain and grain refinement.

关 键 词：输送管 焊接 腐蚀 超临界 二氧化碳 

分 类 号：TG172[金属学及工艺—金属表面处理]