Straight seam steel pipe straightening method

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

Reason: The normalizing of the weld is not sufficient, and there is thermal stress on the side of the pipe near the weld, so it bends in one direction after cooling.

Solution: 1. Adjust the intermediate roller to appropriately increase the deflection curve; 2. Straighten twice; 3. When it is impossible to straighten directly, the tube is tempered as a whole.

2. Straight seam steel pipes irregular bending

Reasons: 1. The pressure between the three rollers is inconsistent; 2. The straightening roller is worn out.

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

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

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

Solution: adjust the rolling angle to be as consistent as possible; adjust the straightening pressure appropriately.

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

Reason: 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 phases between the three straightening rollers are improperly distributed or overlapped, and the roller pressure is too high.

Solution: Adjust the angle between the rollers and the rollers appropriately, and adjust the pressure of the rollers on the tube.

With the advancement and development of science and technology, many new technologies have been applied in steel pipe straightening machines. For example, the seven-roll type straightening machine improved and applied by a company, the model is 3-1-3 steel pipe straightening machine. It uses a different structural form from the usual six-roll straightening machine, and solves the adjustment problem of the straightening roll group in the circumferential direction. The characteristic is that the driving roller adjusts its upper and lower heights by adjusting the inclined iron, so that the three straightening rollers can be adjusted radially in the direction of 120° in the circumference, and the straightening center line is always kept unchanged. The advantage is that the structure Simple and easy to adjust, the rectified pipe is uniformly stressed on the circumference. Therefore, the straightening accuracy is high and good, and the range of applicable specifications is large.