基于大应变下CT80连续管疲劳寿命研究
Study on Fatigue Life of CT80 Grade Coiled Tube Based on Large Strain
毕宗岳1,2, 井晓天1, 何石磊2, 张晓峰2
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作者单位：Study on Fatigue Life of CT80 Grade Coiled Tube Based on Large Strain
中文关键字：连续油管； 大应变； 疲劳寿命； M/A岛
英文关键字：coiled tube; large strain; fatigue life; M/A islands
中文摘要：对国产CT80钢级连续油管在34.47 MPa内压和大应变下进行弯曲疲劳试验，研究了不同全管体热处理温度、表面缺陷等因素对疲劳寿命的影响。 结果表明，在760～820 ℃，可以获得由针状铁素体、等轴铁素体、多边形铁素体与9.3%～9.5% M/A岛组成的混合组织，此时连续油管具有优异的低周疲劳性能；同时研究表明，焊缝中夹杂物、气孔及管体表面缺陷是影响连续油管疲劳寿命的主要因素， 而无缺陷管材的疲劳失效断口一般位于试样的拉伸或压缩面上。
英文摘要：The effects of heat treatment temperature and surface defects on the fatigue life of CT80 grade coiled tube were studied by bending fatigue testing under internal pressure and large deformation. The results show that the coiled tube which gets the mixture of acicular ferrite, equiaxial ferrite, polygonal ferrite and approximately 9.3%～9.5% M/A islands under heat treatment temperature from 760 ℃ to 820 ℃ has the longest fatigue life. And the fatigue life is mainly affected by the defects, which are impurities or pores in the seam and tube surface imperfection. But the fracture of tubes without defects lies in the surface of tensile or compressed parts.