Straight seam steel pipe wall thickness control is a difficult production. At present, the methods adopted by vertical seam welded pipe manufacturers to improve wall thickness accuracy generally include:
1, tube heating
Heat to the average to prevent a sharp rise in temperature above and below. Every time the take-off and landing temperature remains stable, the maximum lifting temperature does not exceed 30 degrees.
2, mill spindle
The average wall thickness of thick-walled tubes and solid blanks significantly reduces the probability of bending deformation of the mandrel, which can effectively improve the accuracy of the wall thickness.
3, the accuracy of the mandrel
The machining accuracy is controlled within 0.1mm ± outer core, and the deviation of the straightness of the mandrel does not exceed 5mm. During welding, a sizing pin is positioned between the two core rods to avoid excessive deviation of the total straightness of the welding.
4, the perfect process
Determine whether the centering roller device is in place, adjust the relevant core roller in the middle, open the same opening angle and size, and pass the middle of the rolling core in the rolling line.
5, centering roller
The perfect process is to avoid the state of center thinning and wall thickness exceeding the control limit and improve the wall thickness accuracy.
6, perforated mandrel
Perforated mandrel diameter Φ108mm - Φ114mm general choice, wall thickness requirements ≥ 25mm and wall thickness average thick-walled pipe.
7, scroll the middle line
Make sure that the middle line of the puncher is consistent with the centerline of the perforated trolley to prevent "roll-up" or "down-rolling", so that the billet is affected by the average force during the perforation process.
8, roll things
The wear of heads, guides, rollers and other rolling objects should be changed in real time.
9, Roller
Roller distance must be in the middle of the rolling line. In the middle of punching and rolling, the distance between the guide roller and the middle of the roller is ensured, and the distance between the upper roller and the lower roller is equal to the left and right rollers.
