CT80连续油管疲劳特性研究及断口分析
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摘要
研究了CT80连续油管疲劳特性,并对其疲劳断口进行分析。结果表明:在应力幅值为250MPa时,其疲劳寿命达到了2×10~6;疲劳裂纹在材料表面或靠近表面的位置处萌生,且在疲劳源附近观察不到疲劳辉纹。随着应力幅值的增大,疲劳裂纹源区的面积减小,甚至会出现多个疲劳源;在较大应力幅值下,断口没有明显的疲劳源区,断裂近似于静载断裂,呈明显的剪切斜断口;疲劳裂纹扩展区附近呈现出放射状条纹,可观察到大量疲劳辉纹,同时还有二次裂纹。应力幅值越高,疲劳辉纹的间距就越大;疲劳瞬断区则由大量韧窝构成,从一些韧窝中可观察到断裂的第二相颗粒。
The fatigue characteristics of CT80 coiled tubing were researched and its fatigue fracture was analyzed. The results show that when the stress amplitude is 250 MPa, its fatigue life reaches 2×10~6. The fatigue cracks usually appear on the surface of the material or near the surface, and the fatigue striations can not be observed in the fatigue source. With the increase of stress amplitude, the area of fatigue crack source decreases, and even multiple fatigue sources appear. Under larger stress amplitude, there is no obvious fatigue source in the fracture, and the fracture is similar to the static load fracture, which shows obvious shear oblique fracture. The radial streaks appear near the fatigue crack propagation zone, and a large number of fatigue striations can be observed and secondary cracks appear. The higher the stress amplitude, the larger the spacing of the fatigue striations. The final fatigue fracture zone is composed of a large number of dimples, and the fractured second phase particles can be observed in some dimples.
The fatigue characteristics of CT80 coiled tubing were researched and its fatigue fracture was analyzed. The results show that when the stress amplitude is 250 MPa, its fatigue life reaches 2×10~6. The fatigue cracks usually appear on the surface of the material or near the surface, and the fatigue striations can not be observed in the fatigue source. With the increase of stress amplitude, the area of fatigue crack source decreases, and even multiple fatigue sources appear. Under larger stress amplitude, there is no obvious fatigue source in the fracture, and the fracture is similar to the static load fracture, which shows obvious shear oblique fracture. The radial streaks appear near the fatigue crack propagation zone, and a large number of fatigue striations can be observed and secondary cracks appear. The higher the stress amplitude, the larger the spacing of the fatigue striations. The final fatigue fracture zone is composed of a large number of dimples, and the fractured second phase particles can be observed in some dimples.
引文
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[2]毕宗岳.连续油管及其应用技术进展[J].焊管,2012(9):5-12.
[3]张啊妮,石凯,刘彦明,等.连续油管管-管对接焊焊前准备工作的探讨[J].热加工工艺,2010,39(5):115-117.
[4]蔡亚西,施太和,王幼金.连续油管柱振动分析[J].西南石油学院学报,1998,20(1):59-60.
[5]李小影.CT80连续管的疲劳性能测试[D].西安:西安石油大学,2009.
[6]武岳.连续管焊接热影响区温度分布及组织影响[D].西安:西安石油大学,2014.
[7]高霞.连续管疲劳寿命的研究[D].西安:西安石油大学,2008.
[8]金属材料-疲劳实验-轴向力控制方法:GB/T3075-2008[S].
[9]陈晓峰,党万腾,唐维,等.航空AZ31镁合金腐蚀疲劳性能研究[J].热加工工艺,2017,46(22):92-94.
[10]谢学涛,何柏林.结构钢焊接接头的超高周疲劳行为研究进展[J].热加工工艺,2017,46(21):5-8.
[11]蹇海根,姜锋,文康,等.不同应力下7B04铝合金的疲劳断口[J].中南大学学报:自然科学版,2010,41(1):132-137.
[12]王弘,高庆.40Cr钢超高周疲劳性能及疲劳断口分析[J].中国铁道科学,2003(6):94-99.
[13]李旭东,穆志韬,刘治国,等.LY12CZ航空铝合金腐蚀疲劳断口研究[J].装备环境工程,2013,10(4):9-12.
[14]胡海涛,李玉龙,索涛,等.2024铝合金振动疲劳特性及断口分析[J].航空材料学报,2013,33(4):78-83.
[15]王艺淋,潘清林,韦莉莉,等.高强7050-T7451铝合金厚板的疲劳断口特征[J].机械工程材料,2013,37(6):26-30.