摘要
从断口形貌观察、金相组织的检验、腐蚀产物成分分析等方面对液化气原料罐法兰与入口管线接头的失效原因进行了分析,认为是16Mn钢在含有H2S的腐蚀介质中,在焊接残余应力和工作载荷的共同作用下,由于应力腐蚀而产生的沿晶脆性开裂。裂纹起始于内表面法兰侧焊缝热影响区熔合线附近(马氏体区),裂纹源起始于该区域的蚀坑或焊缝根部余高应力集中部位,同时出现多处裂纹源,每个微小裂纹在该区域内沿焊缝纵向扩展最终连接成大裂纹,并向纵深扩展,直至穿透。并提出了相应的措施防止此类事故的发生。
The failure reasons of the joint between the liquefied gas raw material jar flange and entrance pipeline were analyzed by the port morphology,metallographic microstructure and the corrosion outcome composition.The results show that 16Mn steel experiences the intergranular brittle cracking because of the stress corrosion environment in which there are the corrosion medium of H2S,the welding residual stress and work load.The crack originates from the fusion area（martensite area）of HAZ flange-side of welding seam on the interior surface.The origin of the crack starts from corrosion pits or stress concentration location of the root of weld and weld reinforcement.And several origins appear at the same time.Every tiny crack expands in the area along the welding seam longitudinally and joins into big one,which expands along the depth,until penetrating through the whole depth.Some corresponding measures were put forward to prevent the occurrence of the accident.
出处
《热加工工艺》
CSCD
北大核心
2011年第1期172-174,共3页
Hot Working Technology
关键词
断口分析
H2S腐蚀
失效分析
fracture analysis
H2S corrosion
failure analysis
