摘要
N80 1类油管属于非调质经济型低碳低合金钢管。对发生脆性断裂的N80 1类油管进行化学成分、力学性能、微观组织、断口形貌及微区能谱等分析,判断油管断裂机理为:由于钢管终轧后或者正火处理时冷却速度较快,钒的碳氮化合物析出不充分,较多的钒元素仍固溶于奥氏体中,提高局部淬透性,促进马氏体转变,尤其是内表面型变量较大的情况下,马氏体带状组织偏析较明显,严重降低了油管韧性,导致油管在使用过程中发生脆性断裂。将失效油管重新加热到850℃,通过控制冷却速度消除马氏体相后,得到细小均匀的珠光体和铁素体组织,油管强韧性良好。
The Non-quenched and tempered N80 tubing belongs to economical low alloy steel. The chemical composition, microstructure, mechanical property, fracture morphology and micro-area chemical composition of the brittle fractured tubing were analyzed. The results showed that the inhomogeneous cooling after finish-rolling or normalization and segregation of V element results in the hard-brittle banded martensite formation in the tubing, which significantly reduced the toughness of tubing. N80 tube brittle fractured from the banded structure of martensite. The failure tubing was re-heat-treated to 850℃ , the martensite was eliminated by controlling cooling rate, the uniform fine pearlite and ferrite, and good toughness tubing was obtained.
作者
路彩虹
王林
冯春
韩礼红
朱丽娟
蒋龙
朱丽霞
LU Caihong1 , WANG Lin2, FENG Chun1 , HAN Lihong1 , ZHU Lijuan1 , JIANG Long1 , ZHU Lixia1(1. CNPC Tubular Goods Research Institute, State Key Laboratory for Performance and Structural Safety of Petroleum Tubular Goods and Equipment Materials, Xi ＇an, Shaanxi 110011, China; 2. Changqing General Drilling Company, Yulin, Shaanxi 719000 , Chin)
出处
《石油管材与仪器》
2018年第2期49-52,共4页
Petroleum Tubular Goods & Instruments
关键词
N801类油管
脆性断裂
马氏体带状组织
成分偏析
non-quenched and tempered tubing
brittle fracture
banded martensite microstructure
element segregatioin
