摘要
某海上天然气气田井口管线立管焊接三通服役过程中出现贯穿裂纹,引起燃气泄漏事故。采用直读光谱仪分析化学成分,显微硬度计测试硬度,电子万能试验机测试力学性能,金相显微镜观察显微组织,扫描电镜观察微观形貌,EDS进行元素分析,XRD进行物相分析。结果表明,三通开裂失效裂纹形成机制为应力集中引起的腐蚀开裂,裂纹在根部焊缝形成以后,以穿晶形式向母材扩展,裂纹在母材区以沿晶断裂的形式穿过存在σ相的区域。
A through-transverse crack occurred on a welded tee-junction of pipeline which served in an offshore gas well,and gas leakage accident was caused. Optical emission spectrometer, microhardness tester, electronic universal testing machine, metallurgical microscope and scanning electron microscope, energy disperse spectroscopy and X-ray diffractometer were used for chemical composition analysis, hardness test, mechanical property test and metallurgical observation, element analysis and phase analysis, respectively. The results show that the crack formation mechanism of tee-junction is corrosion cracking caused by stress concentration. The crack initiates in the root weld, then extends to the base material in transcrystalline fracture, and crack passes through the region with σ phase in the form of intergranular fracture in the base metal region.
作者
杨亚山
张志鹏
YANG Yashan;ZHANG Zhipeng(Zhanjiang Branch ofCNOOC(China)Co,Ltd,Zhanjiang 524000,China)
出处
《热加工工艺》
北大核心
2020年第13期151-155,共5页
Hot Working Technology
关键词
双相不锈钢
脆断
应力集中
腐蚀开裂
dual phase stainless steel
brittle fracture
stress concentration
corrosion cracking
