Today, Oil drilling tool supplier will give you the reason for the failure of the oil drill pipe.
According to the analysis of oil drill pipe's working environment and force, the main failure forms of drill pipe are fracture, plastic deformation (such as bending), and serious wear of screw. The failure in the form of fracture is more serious. The failure form is that the drill pipe will break when the shaft shoulder of the drill pipe head is subjected to great torsion and impact force. After the fracture occurs, the three-bit bit loses its connection with the outside world and can only stay in the formation instead of being taken out. The three-bit bit is quite expensive, which can cause considerable losses to the customer.
The reason of fracture is usually due to the high hardness, poor plasticity and toughness at the shaft shoulder of the drill pipe head connected with the pipe body. Through the analysis of metallographic structure, the grain size grade of the tempered sostenitic structure (the tissue obtained by quenching at high temperature) in this part is usually not within the required grade range, which has a great relationship with the quenching process.
In addition to fracture, there is bending. That is the drill pipe body part plastic deformation. When the bending radian of the tube body is large and exceeds the elastic limit of the tube body, plastic deformation occurs. The plastic deformation of the drill pipe has little impact on the customer and no serious impact caused by the fracture. Only after straightening, the drill pipe can be recovered and put back into use again. The reason for the plastic deformation is closely related to the quenching and quenching treatment of the drill pipe. If the hardness of the tempered drill pipe is low, there is less tempered sostenitic tissue in the tissue or the grain of the tempered sostenitic is relatively coarse and the lamella spacing is relatively large, then the plasticity and toughness of the drill pipe are poor, then bending is inevitable.
The wear phenomenon of the drill pipe screw is related to the surface hardness of the screw, which is related to the quality of the product in the chrome plating process and has nothing to do with the tempering treatment of petroleum. The failure reason of the oil drill pipe is not further analyzed here.
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