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　　Thick wall seamless steel pipe is the main type of seamless steel pipe in manufacturing and daily life. The bending of thick wall seamless steel pipe during heat treatment can be controlled from the following aspects:

　　1. Select the layer by layer refrigeration processing process of external spraying before internal spraying. Because the internal sprinkler of the thick wall seamless steel pipe flows into the other end from one end of the thick wall seamless steel pipe, the refrigeration rate of the thick wall seamless steel pipe is different on both sides, resulting in the bending of the thick wall seamless steel pipe.

　　2. Reduce the length of the overhanging end of the thick wall seamless steel pipe on the rotating wheel. According to the reasonable layout of effective rotating wheels and the length control of thick wall seamless steel pipe, the hanging amount at the top of thick wall seamless steel pipe is controlled to be ≤ 600mm, which can reasonably reduce the centripetal force during heat treatment and reduce the bending of thick wall seamless steel pipe and hydraulic steel pipe.

　　3. Effectively control the rotating wheel speed ratio.

　　4. Operate the water quenched rotating wheel core. The core error of rotating wheel has a great influence on the bending of thick wall seamless steel pipe during heat treatment. Through scientific research, the core deviation of the rotating wheel should be adjusted within 0 ~ 5mm.

　　5. Control the internal and external water spraying volume and uniformity. When the external layer by layer flow refrigeration and inner diameter gushing method is selected for the heat treatment refrigeration of oil and gas well pipes, the size and symmetry of external sprinkling water, the size of internal sprinkling water and the influence of internal nozzle are also the key factors affecting the bending degree of thick wall seamless steel pipe during water quenching.

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