SiCl_(4)冷氢化工序气气换热器壳体开裂失效原因分析及措施  

Analysis and measures for cracking and failure of gas heat exchanger shell in SiCl_(4)cold hydrogenation process

作　　者：刘晶[1] LIU Jing(Sinopec Chuanwei Chemical Co.,Ltd.,Chongqing 401220,China)

机构地区：[1]中国石化集团川维化工有限公司,重庆401220

出　　处：《生态产业科学与磷氟工程》2025年第3期123-128,共6页Eco-industry Science & Phosphorus Fluorine Engineering

摘　　要：对气气换热器的S31608外壳体在冷氢化装置中发生开裂失效现象的原因进行研究,采用金相分析、能谱分析、扫描电镜等方法对外壳体失效部位的化学组成、微观形貌以及腐蚀产物等进行分析。结果表明:换热器壳体的失效形式主要为应力腐蚀开裂,裂纹形态不规整,局部发生贯穿性开裂。腐蚀区域均为沿晶+穿晶解理断口特征,但不同区域沿晶断口占比不同,局部存在沿晶二次裂纹。断口表面不同区域均检测到较高含量的Cl元素,在壳体内压作用下,换热器壳体发生应力腐蚀开裂。除此以外,断口表面存在碳化物析出,主要为铬元素的碳化物,导致晶粒与“贫铬区”之间存在着一定的电位差,造成“贫铬区”的选择性局部腐蚀。The cracking and failure reasons for the S31608 outer shell of the gas heat exchanger in the cold hydrogenation unit are analyzed.Metallographic analysis,energy spectrum analysis,SEM and other methods are used to analyze the chemical composition,microstructure and corrosion products of the failed part of the outer shell.The results show that the main failure mode of the heat exchanger shell is stress corrosion cracking.The crack morphology at the port position is irregular,with locally penetrating cracks occurring.The corrosion area is characterized by intergranular and transgranular cleavage fractures,but the proportion of intergranular fractures varies in different areas,and there are secondary cracks.High level of Cl element is detected in different areas of the fracture surface,under the pressure inside the shell,stress corrosion cracking occurs in the heat exchanger shell.In addition,there is carbide precipitation on the surface of the fracture,mainly chromium carbides,which leads to a certain potential difference between the grains and the"chromium depleted zone",causing selective localized corrosion in the"chromium depleted zone".

关 键 词：四氯化硅 三氯氢硅 冷氢化 沿晶断裂 穿晶断裂 失效 应力腐蚀 

分 类 号：TG172.9[金属学及工艺—金属表面处理]