焊缝为镍基合金的管线钢焊接接头应力腐蚀性能  

SSCC properties of welded joints to weld nickel-based alloy

作　　者：李杰祥[1] 李云涛[1] 韩永典[2] 赵迎新[1] 

机构地区：[1]天津理工大学材料科学与工程学院,天津300384 [2]天津大学材料科学与工程学院,天津300072

出　　处：《焊接学报》2017年第8期55-58,共4页Transactions of The China Welding Institution

摘　　要：用镍基合金Arc625焊材,采用钨极惰性气体保护焊(tungsten inert gas welding,TIG)方法焊接X65管线钢.针对该类焊接接头,通过显微组织观察、电化学测试、氢渗透试验、四点弯曲以及能谱分析研究其H_2S应力腐蚀开裂(sulfide stress corrosion cracking,SSCC)行为.结果表明,该类焊接接头熔合线处有硬脆碳化物聚集,焊缝与热影响区间电化学腐蚀性能差异较大,焊缝的自腐蚀电流密度比热影响区小一个数量级,该类焊接接头整体抗氢渗透能力较强,SSCC试验后试样在熔合线处出现了裂纹,该裂纹由阳极溶解和氢渗透的双重作用所致.熔合线处C元素的聚集和Ni,Cr元素的偏析对焊接接头SSCC性能影响较大.X65 pipeline steel was welded by Tungsten Inert Gas Welding TIG using nickel base alloys (Arc625).For the welded joints,through the observation of microstructure,electrochemical test,hydrogen permeation test,four point bending and spectrum analysis of the H_2S sulfide stress corrosion cracking (SSCC) behavior.The results showed that there were hard and brittle carbides in the fusion line.The electrochemical corrosion behavior of weld and HAZ was quite different,the self-corrosion current density of welding seam is one order of magnitude smaller than that of HAZ.This kind of welded joint had strong hydrogen permeation resistance.After the SSCC test,the crack appeared at the fusion line,which was caused by the double effect of anodic dissolution and hydrogen permeation.The aggregation of C and the segregation of Ni and Cr at the fusion line had a great influence on the SSCC performance of the welded joint.

关 键 词：镍基合金焊材 管线钢焊接接头 H2S应力腐蚀 开裂 

分 类 号：TG174.3[金属学及工艺—金属表面处理]