Seamless pipe is an important type of steel pipe in production and life, and is an important and durable steel in steel pipes. Seamless steel pipes also encounter bending deformation during use. When the seamless steel pipe is bent and deformed, as long as it can be corrected, the seamless steel pipe can continue to be used, otherwise the seamless steel pipe will affect its use. The curvature of the seamless steel pipe can also be controlled, and it should be controlled from the following aspects:
The bending degree of the seamless steel pipe during quenching can be controlled from the following aspects:
(1) Adopt the step-by-step cooling process of first external spraying and then internal spraying. Because the water spray inside the seamless steel pipe flows from one end of the seamless steel pipe to the other end, the cooling rates of the seamless steel pipes at both ends are different, causing the seamless steel pipe to bend. Therefore, external water spray cooling can be used to make the surface of the seamless steel pipe undergo structural changes first, and then the internal water spray cooling method can be used to avoid bending distortion of the seamless steel pipe. The internal water spray is 2~10s later than the external spray.
(2) Reduce the length of the suspension end of the seamless steel pipe on the rotating wheel. Through the reasonable layout of the rotating wheel and the length control of the seamless steel pipe, the hanging amount of the end of the seamless steel pipe is controlled to ≤600mm, which can effectively reduce the centrifugal force and the bending degree of the seamless steel pipe end during quenching.
(3) Reasonably control the rotation speed of the rotating wheel.
(4) Control the center of the water quenching rotating wheel. The center deviation 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 0-5 mm.
(5) Control the amount and uniformity of water spray inside and outside. When the quenching and cooling of the steel pipe adopts the laminar flow cooling on the outer surface and the inner axial spraying method. The size and uniformity of the outer spray water, the size of the inner spray water and the alignment of the inner nozzle are also important factors affecting the bending degree of the seamless steel pipe during water quenching.
The bending degree of the seamless steel pipe during quenching can be controlled from the following aspects:
(1) Adopt the step-by-step cooling process of first external spraying and then internal spraying. Because the water spray inside the seamless steel pipe flows from one end of the seamless steel pipe to the other end, the cooling rates of the seamless steel pipes at both ends are different, causing the seamless steel pipe to bend. Therefore, external water spray cooling can be used to make the surface of the seamless steel pipe undergo structural changes first, and then the internal water spray cooling method can be used to avoid bending distortion of the seamless steel pipe. The internal water spray is 2~10s later than the external spray.
(2) Reduce the length of the suspension end of the seamless steel pipe on the rotating wheel. Through the reasonable layout of the rotating wheel and the length control of the seamless steel pipe, the hanging amount of the end of the seamless steel pipe is controlled to ≤600mm, which can effectively reduce the centrifugal force and the bending degree of the seamless steel pipe end during quenching.
(3) Reasonably control the rotation speed of the rotating wheel.
(4) Control the center of the water quenching rotating wheel. The center deviation 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 0-5 mm.
(5) Control the amount and uniformity of water spray inside and outside. When the quenching and cooling of the steel pipe adopts the laminar flow cooling on the outer surface and the inner axial spraying method. The size and uniformity of the outer spray water, the size of the inner spray water and the alignment of the inner nozzle are also important factors affecting the bending degree of the seamless steel pipe during water quenching.
