温度对异金属焊接接头CO_2腐蚀的影响  

Effect of temperature on CO_2 corrosion of dissimilar weld joint

作　　者：王晶[1] 路民旭[1] 杨萍[1] 张雷[1] 常炜[2] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]中海石油中国有限公司北京研究中心,北京100083

出　　处：《焊接学报》2012年第11期26-30,114,共5页Transactions of The China Welding Institution

基　　金：国家科技重大专项资助项目(2011ZX05056)

摘　　要：为研究温度对异金属焊接接头CO2腐蚀的影响,使用熔化极气体保护焊(MIG)方式焊接X70管线钢和2205双相不锈钢.对基材/焊缝界面的组织和不同温度下的CO2腐蚀形貌进行了观察和分析.结果表明,焊缝侧显微组织呈树枝状奥氏体组织;焊缝存在较窄的熔合区且存在第二类边界线,Ni,Cr等元素存在浓度梯度.与低温相比,高温下焊接接头微合金钢侧产生较严重的CO2腐蚀,微合金钢表面的腐蚀产物膜呈疏松状,焊缝侧腐蚀产物膜较致密.电解液中两侧母材及焊缝的电位差、温度的不同导致离子的迁移速率不同,造成微合金钢和焊缝的腐蚀倾向不同.To study the effect of temperature on CO2 corrosion behavior of dissimilar weld joint,dissimilar weld joint of X70 pipeline steel and 2250 duplex stainless steel welded by metal inertia gas welding was used experimentally.Microstructure of X70/weld joint interface and CO2 corrosion morphologies in weld joint at different temperatures were observed and analyzed.The results showed that dendritic structure appeared in weld joint.Narrow fusion zone and typeⅡboundary existed between micro-alloy steel and weld joint,and obvious concentration gradient of Ni and Cr elements was observed.Serious corrosion occurred in HAZ of micro-alloy at high temperature other than at low temperature.Corrosion product on surface of micro-alloy was shown loose while that on surface of weld joint was shown compact.Such different corrosion tendency of micro-alloy and weld joint was probably caused by the different ionic migration ratios as a result of different corrosion potentials of metals and different temperatures.

关 键 词：温度 异金属焊接接头 组织 腐蚀速率 机理 

分 类 号：TG172.9[金属学及工艺—金属表面处理]