Straight seam steel pipes straightening method

1. The straight seam steel pipe is bent in the same direction as the weld

Reason: Insufficient normalizing treatment of the weld seam, thermal stress exists on the side of the pipe near the weld seam, so it bends in one direction after cooling.

Solutions: 1. Adjust the middle roller to increase the deflection curve appropriately; 2. Straighten twice; 3. When straightening cannot be done directly, temper the pipe.

2. Straight seam steel pipe is bent irregularly

Reasons: 1. The pressure between the three rollers is inconsistent; 2. The straightening roller wears a lot.

Solution: Check and adjust whether the upper straightening roller is loose, and use a sample stick to straighten the length of the contact line between the three lines.

3. The length of the straight seam steel pipe is greatly shortened

Reason: The rolling angle difference between the three straightening rollers is too large; the straightening pressure is relatively large.

Solution: Adjust the roller pressure angle to be as consistent as possible; properly adjust the straightening pressure.

4. One end of the straight seam steel pipe is bent

Cause: The distance between the rollers is too large.

Solution: Choose a straightening machine with a smaller spacing suitable for the corresponding pipe diameter.

5. The head of the straight seam steel pipe is not round

Reason: The contact phase between the three straightening rollers is improperly distributed or overlapped, and the roller pressure is too large.

Solution: Properly adjust the angle between the rollers and the pressure of the rollers on the pipe.

With the advancement and development of science and technology, many new technologies have been applied to steel pipe straightening machines. For example, the seven-roller type straightening machine was improved and applied by a certain company, the model is a 3-1-3 steel pipe straightening machine. It adopts a different structural form from the usual six-roller straightening machine and solves the problem of adjusting the straightening roller group in the circumferential direction. The characteristic is that the driving roller adjusts its height up and down by adjusting the inclined iron, so that the three straightening rollers can be adjusted radially in the direction of 120° of the circumference, while the straightening center line remains unchanged. The advantage is that the structure is simple and easy to adjust, and the force on the circumference of the pipe to be corrected is uniform. Therefore, the straightening accuracy is high and good, and the applicable specification range is large.