N80-1油管液压试验开裂原因分析

Analysis of Reasons for Cracking of N80-1 Tubing during Hydrostatic Test

分析了N80-I钢级油管在静水压试验期间发生开裂的原因。检查发现失效油管的断口为典型脆性断口,断口前端的管材内壁存在划痕缺欠,划痕处产生应力集中,在承压时划痕底部萌生裂纹,是材料失效的诱因;材料内部严重的带状组织使油管横向力学性能下降、止裂能力较差,是油管液压试验开裂的主要原因。

Analyzed in the essay are the causes for the cracking of the N80-1 tubing during the hydrostatic test.It is revealed via checking that the fracture of the failure tubing is a kind of typical brittle fracture,and that scratch defect is found on the inner surface of the pipe section in front of the fracture,where the stress is concentrated,and when pressed,cracks are initiated at the bottom of the scratch defect,which is just the incentive for the said failure;and furthermore the serious banded structure as existing in the material gets the transversal mechanical properties weakened,and leads to poor crack-resistance,which is regarded as the major reason for the above mentioned cracking.