P110套管管体纵裂失效原因分析
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摘要
某厂生产的一支P110钢级套管在防腐现场被发现存在长约7 m的纵裂裂纹。为分析裂纹产生的原因,通过宏观形貌观察、磁粉检测和化学成分分析、力学性能试验等,对该支套管进行了失效分析。试验结果表明,该套管材料的化学成分、力学性能指标等符合API SPEC 5CT—2011标准要求。纵裂是由于裂纹形成于轧管初期或轧管之前,后续的热处理及静水压试验使其进一步扩展,应力释放的延时效应最终造成管体表面贯穿性纵向开裂。最后提出改进措施,降低了产品报废率,挽回了经济损失,提高和稳定了产品的成材率。
A P110 casing was found with a 7-meter length penetration longitudinal crack at the corrosion protection site. In order to analyze the causes of the cracks, the failure analysis was carried out by macro-morphology observation, magnetic particle detection, chemical composition analysis and mechanical property tests, etc. The results show that the chemical composition and mechanical properties of the failed casing were in accord with API SPEC 5 CT-2011, and the defects were formed in the beginning or before the rolling process, and further extended in the subsequent heat treatment and hydrostatic testing. The time-delay effect of stress release ultimately results in penetrating longitudinal cracking. Finally, some reasonable improvement measures are given, which effectively reduced the scrap rate of products, recovered the economic losses, and improved the quality.
A P110 casing was found with a 7-meter length penetration longitudinal crack at the corrosion protection site. In order to analyze the causes of the cracks, the failure analysis was carried out by macro-morphology observation, magnetic particle detection, chemical composition analysis and mechanical property tests, etc. The results show that the chemical composition and mechanical properties of the failed casing were in accord with API SPEC 5 CT-2011, and the defects were formed in the beginning or before the rolling process, and further extended in the subsequent heat treatment and hydrostatic testing. The time-delay effect of stress release ultimately results in penetrating longitudinal cracking. Finally, some reasonable improvement measures are given, which effectively reduced the scrap rate of products, recovered the economic losses, and improved the quality.
引文
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[10] 张乐,安浩,张瑶,等.P110S钢级油管断裂失效分析[J] .理化检测,2018,54 (11):833-852.
[11] 李斐,路飞飞,王军,等.井口P110套管失效原因分析[J].钢管,2017,46 (6):67-72.
[2] 黄川,黄恺.P110级石油套管的研制 [J] .钢管,1990,1 (6):1-4.
[3] 陈鼎勋.重轨钢U75V钢坯脱碳的研究 [D] .武汉:武汉科技大学,2010.
[4] 吕永鹏,胡德英,焦堂骞,等.30Mn钢调质P110钢级油管热处理工艺研究 [J] .钢管,2017,46 (1):45-49.
[5] 武刚,钱煜,杨力能,等.P110石油套管外表面缺陷分析 [J] .热加工工艺,2013,42(9):234-236.
[6] 赵金锋,刘雅政,李亚欣,等.P110石油套管缺陷分析 [J] .材料热处理技术,2009,38 (6):155-160.
[7] 方剑,李阳华,谢凯意,等.P110钢级套管探伤合格率偏低原因分析 [J] .金属热处理,2011,36:154-156.
[8] 庄钢,尹溪泉.连轧无缝钢管产品缺陷(欠)分析 [J] .钢管,2006,35 (5):26-27.
[9] 王朝阳,王智轶,贺建哲,等.P110级石油套管表面微裂纹原因分析[J] .物理测试,2014,32 (4):39-43.
[10] 张乐,安浩,张瑶,等.P110S钢级油管断裂失效分析[J] .理化检测,2018,54 (11):833-852.
[11] 李斐,路飞飞,王军,等.井口P110套管失效原因分析[J].钢管,2017,46 (6):67-72.