Working Principle And Related Characteristics Of PDC Bit
PDC drill bits rely on cutting teeth mounted on the bit body to cut the ground, and these cutting teeth have two types of structures: composite cutting teeth and column type teeth. The composite cutting tooth is formed by welding the composite piece directly into the groove reserved on the bit body. It is generally used in tire body drill bits; the pillar type cutting teeth are formed by welding the composite sheet on the tungsten carbide tooth pillar, and the pillar is set or welded in the tooth hollow on the drill body during installation, which is generally used in steel body drill bits and also in tire body drill bits.
I. Working Principle of PDC Drill Bit
As a responsible PDC bit company, people have long found from experiments that the tensile strength of rocks is the lowest, the shear strength is the second highest, and the compressive strength is the highest, and the compressive strength is often several times to more than ten times higher than the shear strength. Obviously, it is much easier and more effective to crush the rock by shearing than by crushing, and the composite cutting structure of PDC drill bit takes advantage of this mechanical property of the rock and adopts high efficiency shearing to crush the rock, thus achieving the purpose of fast drilling. When the PDC drill bit enters the soft to medium hard strata, the cutting teeth of the composite chip overcome the stratigraphic stress and slide forward under the action of drilling pressure and torque, the rock is broken and plastic flow is generated in the shearing direction under the action of the cutting teeth, and the rock chips produced by the cutting are in the shape of large pieces, which is very similar to the cutting of metal materials by a tool. The sheared rock chips are then taken away by the nozzle to the ring between the drill bit and the well wall and transported outside the well, for example, we also provide borehole drill bit if you want.
II. Features of PDC drill bit
The disadvantage of PDC bit is that it has poor thermal stability, when the temperature exceeds 700℃, the bonding metal inside the diamond layer will fail and lead to the destruction of the cutting tooth. In the work, the wear surface at the bottom of the cutting tooth has been sliding friction with the rock surface under pressure to produce a lot of friction heat, when the cutting tooth cleaning cooling conditions are not good, the local temperature is high, it may lead to thermal wear of the cutting tooth (350-700 ° C, the cutting tooth wear speed is very fast, this phenomenon is called cutting tooth thermal wear) and affect the normal work of the drill bit, so the drill bit to avoid thermal. Hybrid drill bit is popular amon customers. Therefore, to avoid thermal wear, the drill bit must have good hydraulic cleaning and cooling, lubrication, which is required after the mud flowing from the nozzle, the hydraulic distribution should be reasonable to effectively protect the cutting teeth, which is one of the basic requirements of the drill bit hydrometer. In addition, PDC drill bit should avoid drilling at high speed in high hardness and high abrasiveness strata to avoid high local friction temperature.
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