Roller Cone Drill Bits for Foundation Piles in Hunan

　　The bit leg is the main component of a roller cone drill bit. A drill bit is assembled and welded together from three bit legs. The upper part has a connecting thread for connection to the drilling tool, and the lower part is made into a journal with a certain inclination angle, which forms a bearing pair with the inner bore of the roller cone. The bit leg has a water hole flow channel, where an oil storage pressure compensation device can be installed. The journal bears the load and requires high wear resistance and hardness, while the interior of the base body also needs sufficient strength and impact toughness. II. Cutting structure The cutting structure includes the roller cone and the teeth. The roller cone is a cone on which teeth are mounted (or milled), and is divided into two types: single cone and compound cone. A single cone consists of a main cone and a back cone. The single-cone roller cone moves in pure rolling at the bottom of the well and is suitable for drilling in hard formations. A compound cone consists of three parts: the main cone, the secondary cone, and the back cone. This type of roller cone can not only roll but also slide when working at the bottom of the well, and is used for drilling in softer formations. The teeth on the roller cone are divided into two types: inserted teeth and steel teeth. Inserted teeth are made by drilling holes in the tooth rings on the outer conical surface of the roller cone and inserting cemented carbide teeth of different sizes and shapes; steel teeth are milled directly from the roller cone body. The rows of teeth on the three roller cones of the drill bit mesh with each other, which can effectively and without repetition fully break the rock at the bottom of the well and prevent the teeth from balling up with mud. The shape, size, number, and length of the teeth depend on the hardness of the formation being drilled. The softer the formation, the larger and sharper the teeth and the fewer they are arranged. Conversely, the harder the formation, the smaller and shorter the teeth and the greater their number.