为查明三棱螺旋钻杆管体裂纹产生原因,对其断口组织、化学成分、力学性能及管体内壁刀痕附近应力分布情况进行了分析。结果表明,管体内壁刀痕处存在的应力集中是导致管体产生周向裂纹的主要原因,建议改善三棱螺旋钻杆管体内表面质量,避免加工刀痕的产生。 In order to find out the reason of the crack of the triangular pyramid drill pipe body, the fracture organization, the chemical composition, the mechanical property and the stress distribution around the inner wall of the pipe body were analyzed. The results show that the stress concentration in the inner wall of the pipe body is the main reason that causes the circumferential crack in the pipe body. It is suggested to improve the surface quality of the pipe in the triangular pipe and prevent the generation of machining marks.