连续油管斜接焊缝弯曲过程应变分析

Strain Analysis of Inclined Weld Bending of Coiled Tubing

针对连续油管使用过程中出现的对接斜焊缝失效问题,采用ANSYS有限元分析软件建立了连续油管弯曲-矫直几何模型,对HS110钢级Φ50.8 mm×4.78 mm连续油管斜接焊缝的疲劳应变强度进行了分析。分析结果显示,连续油管斜接焊缝热影响区在弯曲状态下的等效应变比本体材料高30%左右;零内压弯曲情况下,随着循环次数的增加,弯曲后等效应变和矫直后残余应变在弯曲内侧内壁上增长最快;带压作业情况下,当内压超过15 MPa后,其残余应变迅速增加。研究表明,连续油管在弯曲作业过程中,斜接焊缝热影响区的强度有较大程度下降,连续油管的累积应变在弯曲内侧内壁处累积最快,此处易发生疲劳失效。

Aiming at the inclined butt weld failure during the use of coiled tubing, HS110 Φ50.8 mm ×4.78 mm coiled tubing inclined weld fatigue strength was analyzed by using ANSYS finite element analysis software to establish coiled tubing bending-straightening geometry model. The analysis results showed that the equivalent strain of the heat affected zone(HAZ) of the inclined weld of coiled tubing in the bending state was about 30% higher than that of the body material;with zero internal pressure bending, the equivalent strain after bending and residual strain after straightening increased most rapidly in bending the inner wall as the number of cycles increased;with pressure, the residual strain increased rapidly when the internal pressure exceeded 15 MPa. The research indicated that during the process of coiled tubing bending, the strength of inclined weld HAZ decreased greatly, the accumulated strain of coiled tubing accumulated most rapidly at the bending inner wall where the fatigue failure was likely to occur.