Q420qENH钢及其焊接接头在模拟含PM_(2.5)的工业大气介质中干湿循环腐蚀行为研究  

Wet-dry Cycle Corrosion Behavior of Q420q ENH Steel and Its Welded Joint in Simulated Industrial Atmosphere Containing PM_(2.5)

作　　者：张利帅 郭铁明[1] 武维宏 胡焱文 刘晓倩 南雪丽[1] 周贵易 易维斌 ZHANG Lishuai;GUO Tieming;WU Weihong;HU Yanwen;LIU Xiaoqian;NAN Xueli;ZHOU Guiyi;YI Weibin(State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;Gansu Provincial Transportation Planning Survey and Design Institute Co.,Ltd,Lanzhou 730050,China;Gansu Precision Machining Technology and Equipment Engineering Research Center,Lanzhou 730050,China)

机构地区：[1]兰州理工大学有色金属先进加工与再利用国家重点实验室,兰州730050 [2]甘肃省交通规划勘察设计院股份有限公司,兰州730050 [3]甘肃省精密加工技术及装备工程研究中心,兰州730050

出　　处：《表面技术》2024年第2期97-109,共13页Surface Technology

基　　金：甘肃省交通厅科技项目(高震区分幅联塔钢混组合梁斜拉桥关键技术及产业化应用研究)(202102);国家自然科学基金(52161007);甘肃省科技重大专项(22ZD6GA008)。

摘　　要：目的 研究桥梁耐候钢板材及其焊接接头在模拟含PM_(2.5)的西北工业大气环境中腐蚀行为的区别。方法 采用NaHSO_(3)+SiO_(2)的腐蚀介质进行干湿交替加速腐蚀实验,并采用腐蚀动力学、X射线衍射、扫描电镜+能谱、电化学测试等方法,分析了Q420qENH钢板材、焊缝及热影响区试样的腐蚀趋势、腐蚀类型及锈层的保护性,以及SiO_(2)对腐蚀的影响。结果 Q420qENH板材试样初期腐蚀速率大于焊接试样,中后期2种试样腐蚀速率逐渐下降并趋于一致。3种试样腐蚀类型均为不均匀的全面腐蚀,外锈层均疏松易脱落,但焊缝、热影响区内锈层比板材致密且与钢基体结合紧密,锈层中Cu、Ni元素含量明显高于板材试样。3种试样腐蚀30d的自腐蚀电流密度由大到小的顺序为板材>焊缝>热影响区,自腐蚀电位由大到小的顺序为热影响区>焊缝>板材,焊缝及热影响区试样的锈层电阻分别为板材试样的1.28倍、1.68倍。结论 PM_(2.5)中的主要成分SiO_(2)易在缺陷处沉积,成为腐蚀产物的形核基底,促进了腐蚀产物的非均匀形核,不利于锈层的致密性。热影响区和焊缝形成锈层的保护性、耐蚀性能优于板材试样。In this work,the corrosion behavior of Q420qENH weathering steel and its welded joints in industrial atmospheric environment containing PM_(2.5) was studied by dry-wet alternate accelerated corrosion test.The corrosion trend,corrosion type and rust layer protection of the plate,weld and heat affected zone samples,and the effect of SiO_(2) on corrosion were investigated.In the industrial atmospheric medium containing SiO_(2),the initial corrosion rate of Q420qENH plate sample was higher than that of the welding sample,and the corrosion rate of the two samples gradually decreased and tended to be the same in the middle and late period.During the entire corrosion process,the n values of the plates and welded samples were all less than 1,indicating that the corrosion of Q420qENH steel plates and welded samples was a deceleration process in the northwest industrial atmospheric medium environment containing PM_(2.5).The corrosion types were characterized by general corrosion and local corrosion,but the local corrosion pit size of the plate was large and the corrosion was serious.The outer rust layer of the three samples was loose and easy to fall off,and there were defects such as long cracks and holes.However,the rust layer in the weld and heat affected zone was denser than the plate and closely bonded to the steel matrix,and the content of Cu and Ni elements in the rust layer was significantly higher than that of the plate sample.The three samples all had obvious element enrichment phenomenon,and the Si element enrichment in the rust layer of the weld and heat affected zone samples was less than that of the plate,which indicated that the inner rust layer formed by the weld and heat affected zone samples could be more concentrated.The self-corrosion current of the three samples after corrosion for 30 days wa:plate > weld > heat affected zone,and the self-corrosion potential wa:heat affected zone > weld > plate.The rust layer resistance of the weld and heat affected zone samples was 1.28 times and 1.68 times that of th

关 键 词：Q420qE桥梁耐候钢 焊接接头 西北工业大气环境 PM_(2.5) SiO_(2) 干湿循环腐蚀 

分 类 号：TG172.3[金属学及工艺—金属表面处理]