摘要
针对Ф323.9mm×18mm的X65钢质海洋隔水管,开展了多接头四点弯曲+内压全尺寸疲劳试件试验研究,并采用高清相机、三维视频显微镜对试件疲劳断口进行宏观和微观分析。研究表明,试验用全尺寸疲劳试件焊接接头中存在未熔合等不连续性缺陷,疲劳试件疲劳抗力的薄弱部位分别为管道内表面的焊趾与外表面两条焊道的结合位置,而焊缝区疲劳裂纹扩展路径较为曲折,因而具有较好的抗疲劳裂纹扩展性能。最后建议,通过采取加宽对接接头间的间隙、清洁坡口污染物等措施,可以防止内表面附近的焊接未熔合问题;通过降低管道内表面焊缝余高,打磨外表面焊缝,以减小形状不连续导致的应力集中,最终可提高试件的抗疲劳寿命。
The full-scale four-point bending and internal pressure fatigue test for the multi-joint specimen of a Ф323.9 mm × 18 mm and X65 steel marine riser is carried out, and macroscopic and microscopic analyses of the fatigue fractures of the specimen are conducted with a high definition camera and a 3D video microscope.There are discontinuous defects such as un-melting in the welded joint of the full-scale specimen.The weak fatigue resistance parts of the specimen are in the joint positions of the inner surface weld toe and the two outer surface welds of the pipe.The fatigue crack propagation path of the weld zone is tortuous and it has better fatigue crack growth resistance.The lacking of fusion of inner surface weld can be prevented by widening the gap between the butt joints and cleaning the contaminations of the groove.Reducing the height of the inner surface weld and polishing the outer surface weld can reduce the stress concentration in the discontinuous position, and the fatigue life of the full-scale specimen will be finally improved.
作者
胡艳华
牛虎理
刘剑
HU Yanhua;NIU Huli;LIU Jian(CNPC Engineering Technology Research Co., Ltd., Tianjin 300451, China)
出处
《石油工程建设》
2019年第3期48-51,共4页
Petroleum Engineering Construction
