Drill pipe is a type of steel pipe with a threaded end, used to connect the surface equipment of the drilling rig to the drilling and grinding equipment or bottom hole device located at the bottom of the drilling rig. The purpose of the drill pipe is to transport drilling mud to the drill bit and raise, lower, or rotate the bottom hole device together with the drill bit. The drill pipe must be able to withstand significant internal and external pressure, twisting, bending, and vibration.