厚规格X70管线钢焊接接头盐雾腐蚀行为  

Salt spray corrosion behavior of thick wall X70 pipeline steel welded joints

作　　者：马歌[1] 朱靖玉[1] 左秀荣[1] 洪良[1] 姬颖伦 董俊媛 

机构地区：[1]郑州大学物理工程学院,河南郑州450000

出　　处：《钢铁研究学报》2017年第8期678-683,共6页Journal of Iron and Steel Research

摘　　要：通过金相显微镜、扫描电镜对厚规格X70管线钢焊接接头进行中性盐雾试验(NSS试验)腐蚀产物形貌进行观察,采用EDS、XRD分别对腐蚀产物进行面扫描和物相分析。结果表明,盐雾腐蚀过程先发生点蚀,点蚀逐步发展成全面腐蚀。Cl-引起点蚀,点蚀导致裂纹的产生。腐蚀产物成分均匀,主要由铁的氧化物、氯化物和氢氧化物组成。腐蚀速率随着腐蚀时间的延长变缓慢,腐蚀过程中Cl-易穿过外层疏松的腐蚀产物与基体发生反应,而最内层致密的腐蚀产物膜对腐蚀介质的进一步扩散起到阻挡作用,减缓了反应速率提高了耐蚀性。Neutral salt spray test（NSS test）was carried out on the welded joint of thick wall X70 pipeline steel,and the corrosion products of 1,2,4and 8hwere observed by metallographic microscope and scanning electron microscope.The corrosion product surface was analyzed by EDS,and the composition of corrosion product films was discussed by XRD.The results show that pitting corrosion occurs firstly in the salt spray corrosion process,and the pitting corrosion is gradually developed into an overall corrosion.Cl-causes pitting corrosion,pitting leads to the generation of cracks.The composition of the corrosion product is uniform,which is mainly composed of iron oxide,chloride and hydroxide.The corrosion rate increases slowly with the prolonging of the corrosion time.In the process of corrosion,Cl-reacts with the matrix easily through the outer loose corrosion product,and the dense corrosion product film on the innermost layer that blocks the further spread of the corrosive medium slows the reaction rate and improves the corrosion resistance.

关 键 词：X70管线钢 焊接接头 盐雾腐蚀 腐蚀产物 

分 类 号：TG174.3[金属学及工艺—金属表面处理] TG407[金属学及工艺—金属学]