大型竖井钻机的钻杆及中心管在焊接部位处经常产生脆断现象,这是影响钻井速度的主要原因之一。近年来,有关设计部门从断裂力学的观点出发,对钻杆及中心管的结构、选材、焊接工艺等方面进行了深入地探讨,认为:钻杆及中心管断裂的主要原因是 One of the main reasons that affect the drilling speed is the frequent brittle fracture of the drill pipe and the center pipe of the large shaft drilling machine at the welding place. In recent years, the design department from the point of view of fracture mechanics, the structure of the drill pipe and the center pipe, material selection, welding process and other aspects in-depth discussion, that: the main reason for the drill pipe and the center tube rupture