Longitudinal bending and roundness errors always exist in cold drawn seamless tubing after hot rolling, and these defects are eliminated by the straightening process. Therefore, the straightening process determines the geometry of the cold drawn seamless tubing and also affects its mechanical properties. In the straightening process, if the straightening machine is adjusted properly, the longitudinal bending and roundness errors of the cold drawn seamless tubing can be eliminated, and its mechanical properties can be appropriately improved.

Cold drawn seamless tubing straightening process

1) The cold drawn seamless tubing enters the roller table at the entrance of the leveler from the upstream roller table.

2) When the head of the cold drawn seamless tubing is sensed by the sensor element in the middle of the entrance roller table, the roller table will decelerate.

3) When the head of the cold drawn seamless tubing is sensed by the sensor element at the end of the entrance roller table, the first stage of the entrance roller table falls, and the closing delay of the inlet quick-opening cylinder starts to count.

4) When the pipe head enters the middle position of the inlet straightening roller, the inlet quick opening cylinder is closed, the cold drawn seamless tubing is bitten in, and at the same time the second roller table of the inlet falls.

5) Through the setting of the delay time of the quick-opening cylinder, when the pipe head enters the middle position of the intermediate roll and the exit roll, the quick-opening cylinder of the intermediate roll and the exit roll are closed successively, and the cold drawn seamless tubing enters the straightening process.

6) When the tube tail leaves the sensor element in the middle of the entrance roller, the first section of the entrance roller rises.

7) When the tube tail leaves the sensor element at the end of the inlet roller table, the second section of the inlet roller table rises. At the same time, through the setting of the quick-open cylinder delay, when the tube tail reaches the middle position of the inlet roller, the middle roller and the outlet roller, The quick-opening cylinders of the inlet roller, the middle roller and the outlet roller are opened successively.

8) The outlet roller table rises, and the cold drawn seamless tubing is transported to the baffle at the end of the outlet roller table.

9) The exit roller table descends, the side door of the passage is opened, and the cold drawn seamless tubing rolls onto the L-shaped splicing hook by gravity.

10) The receiving hook falls, and the cold drawn seamless tubing rolls onto the soot-blowing stand to purge the iron oxide scale on the inner surface of the cold drawn seamless  tubing.

Cold drawn seamless tubing precautions

1) When straightening the cold drawn seamless tubing, it is not allowed to produce spiral dents, squares, and hairs, and it is not allowed to straighten the size of the finished pipe to be unqualified.

2) The bending degree of the straightened cold drawn seamless tubing should be in accordance with the "Guidelines for Size and Appearance Inspection" for the finished seamless tubing: the core diameter pipe should be ≯15mm/m, and the cold drawn tubing can be appropriately relaxed.

3) Keep the straightening roller clean. If the roller surface is found to be fluffed, damaged, iron sticking, etc., it should be polished with sandpaper or grinding wheel in time. If the defect is serious and affects the straightening quality of the seamless tubing, the roller should be replaced in time.

4) Large-diameter steel tubing should be carried out on a three-point simply supported straightening machine.

5) Straightening is a process to ensure the straightness of the finished seamless tubing, ensuring that the cold drawn seamless tubing can reach a standard range in actual production.

6) Before driving, check whether the leveler is normal, and add appropriate amount of lubricating oil. When the equipment is in good condition, drive empty for one minute to observe the operation.

7) The bending degree of the incoming cold drawn seamless tubing should not be too large, otherwise, manual initial straightening should be used, and then the material will be straightened when it meets the requirements of the equipment capacity.

8) When straightening, the inclination angle of the straightening roller, the roller distance of the straightening roller and the position of the opposite roller should be adjusted. At the same time, the inlet guide plate should be installed and adjusted correctly to ensure the straightening of the cold drawn seamless tubing quality.