Controlling the curvature of cold drawn seamless pipe during quenching can be carried out from the following aspects:
1) The step-by-step cooling process of external spraying and then internal spraying is adopted. Since the internal water spray of the cold drawn seamless pipe flows from one end of the steel pipe to the other end, the cooling rate at both ends is different, which causes the cold drawn seamless pipe to bend. Therefore, the external water spray cooling can be used first, so that the surface layer of the cold drawn seamless pipe first undergoes structural transformation, and then the internal water spray is used for cooling to avoid the bending distortion of the steel pipe. The delay time of the internal water spray compared to the external nozzle can be 2 ~10s.
2) Reduce the length of the overhanging end of the cold drawn seamless pipe on the rotating wheel. Through reasonable rotating wheel layout and steel pipe length control, the overhang of the end of the cold drawn seamless pipe is controlled to be less than or equal to 600 mm, which can effectively reduce the centrifugal force during quenching and reduce the curvature of the cold drawn seamless pipe end.
3) Reasonably control the speed of the rotating wheel.
4) Control the center of the water quenching rotating wheel. The deviation of the center of the rotating wheel has a great influence on the curvature of the cold drawn seamless pipe during quenching. After research, the center range of the rotating wheel should be controlled within 0 to 5 mm.
5) Control the amount and uniformity of water spray inside and outside. When the quenching and cooling of the oil well pipe adopts the outer surface laminar flow cooling and the inner axial injection method, the size and uniformity of the outer water injection, the size of the inner water injection and the alignment of the inner nozzle are also the curvature of the cold drawn seamless pipe during quenching important influencing factors.
The bending deformation of cold drawn seamless pipe will seriously affect the cold drawn seamless pipe sizes and cause losses in its application in daily life. The use of cold drawn seamless pipe to manufacture mechanical structures or hydraulic equipment can greatly save machining hours, improve material utilization, and help improve product quality.