错边对钢悬链立管横焊接头疲劳性能的影响

Effect of misalignment on fatigue performance of horizontal welded joints in steel catenary riser system

采用填丝TIG方法进行了不同错边量的立管环缝横焊试验,对其接头试样在80,120和175 MPa应力范围下进行了疲劳试验,研究错边对横焊环缝接头疲劳性能的影响.结果表明,错边方式对横焊接头疲劳裂纹起裂位置有重要影响,"上错边"接头的疲劳裂纹主要从根部焊趾上侧起裂,无错边接头的疲劳裂纹主要从根部焊趾下侧起裂,而"下错边"接头的疲劳裂纹则全部从根部焊趾下侧起裂;在相同应力范围下,试样的疲劳循环周次随错边量的增大而降低,当错边量超过0.60 mm后,疲劳循环周次会显著下降.

In order to investigate the effect of misalignment on the horizontal girth weld fatigue performance,the joints of steel catenary riser were welded by TIG welding with filler wire and the fatigue tests of the joints were carried out at the stress range of 80,120 and 175 MPa,respectively.The results indicated that the misalignment mode has a significant influence on the fatigue cracking initiation position of horizontal welding joints.The fatigue crack of uppermisalignment-joint is almost from the upper side of the root toe,and the fatigue crack of joints without misalignment is mainly from the bottom of the root toe,besides,the fatigue crack of down-misalignment-joint is all from the bottom of the root toe.In addition,the fatigue endurance of the specimens is decreased continuously with the increase of the misalignment values at the same stress range,and which is reduced obviously when the misalignment values exceed 0.60 mm.