硫磺装置酸性气分液罐液位计管开裂原因分析  

Reason Analysis of Cracking of Liquid Level Gauge Pipe in Acid Gas Separator Tank of Sulfur Plant

作　　者：鄢长伟[1] 于汉迪 YAN Chang-wei;Yu Han-di(Petrochina Fushun Petrochemical Company,the Three Pil Plant,Fushun 113004,China;Shenyang Zhongke Well Corrosion Control Technology,Co.,Ltd.Shenyang 110000,China)

机构地区：[1]中国石油抚顺石化公司石油三厂,辽宁抚顺113004 [2]沈阳中科韦尔腐蚀控制技术有限公司,辽宁沈阳110000

出　　处：《全面腐蚀控制》2024年第2期50-54,共5页Total Corrosion Control

摘　　要：某石油三厂硫磺装置发现,酸性气分液罐液位计管的底部焊缝处发生了明显的开裂泄漏,通过对液位计进行宏观及低倍分析、材质分析、金相检验以及电镜分析结果表明:液位计管和法兰材质均为S20430不锈钢(200系列);液位计管、法兰以及焊缝的金相组织分别为奥氏体、敏化倾向的奥氏体、铸态奥氏体和少量铁素体;液位计管的开裂失效性质为应力腐蚀,以穿晶扩展为主。造成液位计管与法兰焊接处发生开裂的主要原因为液位计管和法兰采用的均为对应力腐蚀较为敏感的材质,两者焊接区存在残余应力,液位计管底部是一个封闭区,存在酸性介质(H2S溶液和H2CO3溶液)。An obvious cracking leak occurred at the bottom weld of the liquid level gauge tube of an acid gas separation tank in a sulfur plant.The results of macroscopic and low-power analysis,material analysis,metallographic inspection and electron microscope analysis of the liquid level gauge show that the material of the liquid level gauge tube and flange are S20430 stainless steel(200 series).The metal structures of the liquid level gauge tube,flange and weld are austenite,sensitized austenite,ascast austenite and a small amount of ferrite,respectively.The cracking failure property of the liquid level gauge tube is stress corrosion,which is mainly transgranular expansion.The main reason for the cracking of the welding between the liquid level pipe and the flange is that the liquid level pipe and the flange are both made of materials that are more sensitive to stress corrosion,there is residual stress in the welding area of the two,and the bottom of the liquid level pipe is a closed area with acidic medium(H2S solution and H2CO3 solution).

关 键 词：硫磺装置 酸性气分液罐 液位计管 应力腐蚀开裂 

分 类 号：TE-9[石油与天然气工程]