20号钢管状电感探针在模拟某气田环境下的腐蚀失效分析  

Analysis of Corrosion Failure of 20# Steel Tubular Induction Probe in Simulated Environment of a Gas Field

作　　者：李博文[1,2] 赵林[1,2] 台闯[1,2] 

机构地区：[1]中国科学院金属研究所材料环境腐蚀研究中心,辽宁沈阳110016 [2]沈阳科金新材料有限公司,辽宁沈阳110015

出　　处：《石油化工腐蚀与防护》2012年第6期58-61,共4页Corrosion & Protection In Petrochemical Industry

摘　　要：模拟某气田CO2腐蚀环境,利用SEM,EDAX和XRD分析方法,对20号钢管状电感探针的腐蚀机理和失效过程进行了分析研究。结果表明:腐蚀产物分为两层,外层主要由FeCO3晶体和FeS组成,膜层较厚,强度较低且质地疏松多孔;内层主要为FeO和少量FeCl2组成,较外层稍致密,与金属基体间的附着力较差,产物膜易脱落。腐蚀产物膜的多孔特性诱发了局部腐蚀,溶液中Ca2+和Cl-的存在对样品的局部腐蚀起到了促进作用。探针的失效最先从测量试片封堵端开始,焊接工艺遗留残余应力使得此处腐蚀较快,容易发生腐蚀开裂,腐蚀介质从开裂处渗入试片空腔内,加速了探针的失效。The corrosion mechanisms and failure process of 20 # steel tubular induction probe in a simulated CO2 corrosion environment of a gas field are investigated by SEM, EDAX and XRD. The results show that the corrosion products are divided into two layers. The outer layer is mainly composed of FeCO3 crystal and FeS, and the film is larger in thickness, low in density and porous in texture. The inner one mainly consists of FeO and a small amount of FeCI=, and the film is slightly denser than the outer layer. The products film is easy to spall off from this layer because of the poor adhesion to metal matrix. Localized corrosion is induced by porous characteristics of products film, and the corrosion process is promoted because of the Ca2＋ and C1 in the solution. The corrosion failure starts at the top of 20# steel tubular induction probe. The residual stress by welding accelerated the corrosion, which develops into corrosion cracking. The failure process of probe is accelerated with the corrosive media permeating into the cavity of measurement piece through the corrosion cracks.

关 键 词：电感探针 20号钢 CO2腐蚀 失效分析 

分 类 号：TE986[石油与天然气工程—石油机械设备]