is an important steel that is relatively strong and durable, and is widely used in life. The seamless steel pipe will also encounter bending deformation in use. When encountering the bending and deformation of the seamless steel pipe, as long as it can be corrected, the seamless steel pipe can continue to be used. So, how does the seamless tube control its bending during the production process?
Controlling the bending degree of seamless steel pipes 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 inner water spray of the seamless steel pipe flows from one end of the seamless steel pipe to the other end, the cooling rate of the seamless steel pipe at both ends is different, resulting in the bending of the seamless steel pipe. Therefore, the external water spray cooling can be used first, so that the surface layer of the seamless steel pipe undergoes structural transformation first, and then the internal water spray is used for cooling to avoid the bending distortion of the seamless steel pipe. The delay time of the internal water spray compared with the external nozzle can be 2 ~10s.
(2) Reduce the length of the overhanging end of the seamless steel pipe on the rotating wheel. Through reasonable rotating wheel layout and seamless steel pipe length control, the overhang of the seamless steel pipe end is controlled to be less than or equal to 600 mm, which can effectively reduce the centrifugal force during quenching and reduce the bending degree of the seamless steel pipe end.
(3) Reasonably control the rotation 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 bending degree of the seamless steel 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 cooling and the inner axial spray method, the size and uniformity of the external water spray, the size of the internal water spray and the alignment of the inner nozzle. It is also an important factor affecting the bending degree of seamless steel pipes during water quenching.