B_2/DO_3热处理对Fe_3Al基合金在湿H_2S-CO_2-Cl^-环境中耐蚀性的影响  

Effect of B_2/DO_3 heat treatment on corrosion resistance of Fe_3Al matrix alloy in H_2S-CO_2-Cl^- environment

作　　者：王斌[1] 冯泉[1,2] 蒋勇[3] 钟科[3] 杨飞[3] 

机构地区：[1]西南石油大学材料科学与工程学院,四川成都610500 [2]中国石油天然气股份有限公司塔里木油田分公司油气工程研究院防腐工艺研究室,新疆库尔勒841000 [3]四川大西洋焊接材料股份有限公司,四川自贡643010

出　　处：《金属热处理》2016年第3期19-24,共6页Heat Treatment of Metals

摘　　要：针对不同结构对Fe_3Al合金在湿H_2S-CO_2-Cl^-天然气集输环境中耐蚀性的影响,对未处理、经B_2或DO_3热处理的Fe_3Al试样,遵循ASTM G111-97(2013)和NACE TM 0169/G31-12a标准,试验模拟罗家寨气田实际工况进行全浸均匀腐蚀试验,评估其腐蚀速率;采用XRD表征其物相;采用SEM表征其腐蚀前后表面的微观结构;采用EDS测量并统计分析不同结构位置化学成分的差异。结果表明,Fe-28Al-4Cr合金(原子分数,%)在所模拟罗家寨气田实际工况环境中,经168 h后合金表面形成内层以铝氧化物+铁氧化物为主、外层以铁氧化物+铁硫化物为主的双层腐蚀产物膜,内层膜致密而均匀,但受金属基体表面形貌影响会发生开裂。Fe-28Al-4Cr合金表面DO_3结构比B_2结构Fe含量约低1.75at%,而Al含量约高1.64at%。内层腐蚀产物膜主要构成元素Al含量的不同,使合金表面钝化膜生长行为产生差异,进而影响合金耐蚀性;具体表现为2~24 h内因钝化DO_3处理合金的腐蚀速率下降响应更迅速。在所模拟罗家寨气田实际工况环境中,168 h后Fe-28Al-4Cr合金腐蚀速率趋于稳定,为0.238~0.27 mm/y,均达到了实际工程应用的条件。Aimed at gaining an insight into the effects of heat treatment on corrosion resistance of Fe_3 Al alloy in wet natural gas,which is a H_2S-CO_2-Cl^-environment,samples in original state,after B_2 or DO_3heat treatment were prepared,corrosion tests in simulated environment of Luojiazhai gas field were performed on these samples according to ASTM G111-97（ 2013） NACE TM 0169/G31-12a; XRD,SEM,and EDS were employed to investigate phases,microstructure before or after corroding and composition differences between variety microstructures in samples,respectively. The results indicate that a stable bilayer film are formed on Fe-28Al-4Cr alloy（ atom fraction,%） after immersed in simulated environment of Luojiazhai gas field,which is composed of aluminum oxide ＋ iron oxide based inner layer and iron oxide ＋ iron sulfide based external layer. The inner layer is uniform and dense,which may crack on account of metal matrix＇s morphology. B_2 structures exhibit higher surface Fe-content,at about 1. 75at%,than DO_3 structure in Fe-28Al-4Cr,while DO_3 structure have a higher surface Al-content,at around 1. 64at%. The surface Al-content,which is the major layer former element,leads to differences in film growth behavior,then result in effects on corrosion resistant. Such as the corrosion rate of Fe-28Al-4Cr alloy treated by DO_3 has reduced sharply during immersion for 2-24 h. The corrosion rate of the alloy has stabilized at 0. 238-0. 27 mm/y after immersion in simulated environment of Luojiazhai gas field for 168 h,which are all satisfied for practical engineering applications.

关 键 词：FE3AL基合金 H_2S-CO_2-Cl^-环境 B2热处理 DO3热处理 耐蚀性 

分 类 号：TG156.1[金属学及工艺—热处理]