摘要
目前,对在役焊接的研究多集中在套袖焊接接头变形过程与失效机理方面,对套袖的焊接尺寸和应力分布研究较少。为研究管道在役焊接修复残余应力的分布规律及影响区域,采用ANSYS软件建立套袖焊接有限元模型,分析焊接线能、套袖壁厚、管径及压力对套袖焊接残余应力分布的影响,确定套袖最佳壁厚的计算方法,探究管道壁厚、外径、压力及缺陷尺寸与腐蚀应力分布的关系,建立套袖焊接尺寸计算准则并进行现场应用。研究结果表明:套袖焊缝边缘的轴向应力最大,易出现应力破坏现象,焊缝外侧为压应力,内侧为拉应力,主要与熔池冷却收缩效应有关;在熔池冷却收缩和对流换热共同作用下,焊接残余应力分布随套袖壁厚的增大而增大,焊接线能、管径和压力的影响作用可忽略;应力峰值随套袖壁厚的增大先减小再增加,套袖壁厚选取临界壁厚值时焊接点出现氢致开裂的风险最低。所得结果对管道修复时确定套袖的壁厚和焊接尺寸具有指导意义。
The previous researches on in-service welding mostly focus on the deformation process and failure mechanism of the sleeve welding joint and seldom incorporate the geometry and stress distribution of the sleeve.To investigate the distribution pattern and affected zone of the residual stress of pipeline for in-service welding,the sleeve welding finite element model was built in ANSYS,and the influences of weld line energy,sleeve wall thickness,pipe diameter and pressure on the residual stress distribution of sleeve welding were analyzed.The calculation method for the optimal sleeve wall thickness was developed,and the relationships of the corrosion stress distribution with the pipe wall thickness,outside diameter,pressure,and defect size were identified.The calculation criterion of the sleeve welding size was established and applied in the field.The results show that the highest axial stress occurs at the boundary of the sleeve weld joint,which is thus prone to stress rupture.The outside of the weld joint is associated with compressive stress and the inside is found with tensile stress,which is attributed to the cooling shrinkage of the molten pool.Under the joint effects of the molten pool cooling shrinkage and convective heat transfer,the welding residual stress grows with the increasing sleeve wall thickness,while the effects of the weld line energy,pipe diameter and pressure are negligible.The maximum stress first declines and then rises,with the increasing sleeve wall thickness.The risk of hydrogen-induced cracking is the lowest with the critical sleeve wall thickness for welding points.The findings of this research guide the determination of the wall thickness and weld size for pipeline repair.
作者
霍进风
单鲁维
Huo Jinfeng;Shan Luwei(Pipeline Engineering Construction Project Department of PipeChina West-East Gas Transmission Company)
出处
《石油机械》
北大核心
2023年第2期130-137,共8页
China Petroleum Machinery
基金
中国石油天然气股份有限公司“十三五”煤层气重大科技专项“煤层气与煤系地层天然气综合开发技术研究”(2017E-1406)。
关键词
在役管道
焊接修复
残余应力
腐蚀应力
套袖
缺陷尺寸
计算准则
in-service pipeline
welding repair
residual stress
corrosion stress
sleeve
defect size
calculation criterion
