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Application of Laser Quenching in Surface Hardening Treatment of Drill Pipe Joints
Laser quenching on the thread surface of the drill pipe joint
As an indispensable tool for oil drilling, geological drilling and mining drilling, drill pipe plays an extremely important role in the drilling process. The requirements for thread strength during drilling and retracting of drill pipe are very high. The mechanical strength of drill pipe joints treated with traditional surface nitriding hardening technology cannot meet the construction requirements of modern high torque and long distance drilling. There is a new technology to replace the traditional process, laser surface quenching technology came into being.
Laser quenching drill pipe process
Appearance detection of internal and external threads A light-absorbing paint is sprayed with a laser surface quenching and a roughness test is transferred to the next process.
Comparison of laser quenching and nitriding treatment performance
The laser quenching has a hardness value of about 10% higher than that of liquid nitriding, and is stable. The depth of the hardened layer is 2 to 3 times the depth of the hardened layer after nitriding, which greatly improves the mechanical properties of the thread of the drill pipe joint.
Comparison of fatigue life:
The average life of the joint after laser treatment was 288.4×10 ^ 3 , and the average fatigue life of the nitriding treatment was 178.2×10 ^ 3 .
Comparison of wear and tear:
The maximum wear amount of laser quenching treatment was 31.3 mg, and the joint wear amount of nitriding quenching treatment was 62.3 mg (dual: 27CrMnTi, hardness 990 HV. Conditions: room temperature, no lubrication, 200 r/min, pressure 19.6 N, time 2 h).
Comparison of laser and nitriding hardness
Advantages after laser quenching
The surface hardness after laser quenching is about 10% higher than that of conventional heat treatment. The hardness gradient of the quenched layer from the surface to the inside is not large, and the hardness gradient of the hardness layer after conventional quenching is large, resulting in excessive longitudinal hardness difference.
The fatigue resistance and wear resistance of the joint after laser quenching are greatly improved, saving time and labor, and high processing efficiency.