Control of wall thickness of straight seam steel pipe

The control of the wall thickness of the straight seam steel pipe is a difficulty in the production of steel pipes. At present, the methods of wall thickness accuracy in the production of straight seam steel pipe manufacturers generally include:

1. Tube blank heating
The heating should be even and avoid rapid rise and fall of the temperature. The temperature of each rise and fall should be kept stable and slow, and the temperature of the big rise and fall should not exceed 30 ℃.

2. Rolling mandrel
Thick-walled pipes and solid billets with an average wall thickness greatly reduce the probability of bending deformation of the mandrel, which can effectively improve the wall thickness accuracy of the steel pipe.

3. The accuracy of the mandrel
The external machining accuracy of the mandrel is controlled by ±0.1mm, and the straightness deviation of the mandrel does not exceed 5mm. When welding, a precision-machined pin is inserted between the two mandrels for positioning, to avoid excessive deviation of the overall straightness formed by the welding.

4. Process
Determine whether the centering roll device is in place, adjust the center and opening angle of the relevant core rolls, and the opening size of each measure is consistent, and the center of the core roll should be on the rolling line.

5. Centering roller
technology, to avoid the occurrence of center thinning and wall thickness increase and improve the wall thickness accuracy.

6. Perforated ejector
The perforated ejector rod is generally selected as a thick-walled pipe with an outer diameter of Φ108mm-Φ114mm, a wall thickness of ≥25mm, and an average wall thickness.

7. Rolling intermediate line
Make sure that the rolling middle line of the piercing machine is consistent with the middle line of the piercing trolley, to prevent “up rolling” or “down rolling”, so that the tube blank can maintain an even force during piercing.

8. Rolling things
Rolling tools such as worn heads, guide plates, rolls, etc. should be replaced in real-time.

9. Rolling equipment
The middle of roll distance and lead distance must be on the rolling line. The middle line of the guide distance and the roll distance are on the middle line of the piercing and rolling, that is, the upper and lower roll distances are equal, and the left and right guide distances are equal.