1, Billet heating
The heating should be averaged to stop the rapid rise and fall temperature. Every time the temperature rises, it must maintain steady and slow, and the maximum lifting temperature does not exceed 30°C.
2, Mill mandrel
The thick-walled tubes and solid billets with the average wall thickness have greatly reduced the probability of bending and deformation of the mandrel, which can effectively improve the accuracy of the wall thickness of the steel pipe.
3, The accuracy of mandrel
The mandrel's external machining accuracy is controlled to ±0.1mm, and the mandrel's straightness does not exceed 5mm. During welding, a two-piece mandrel is punctured into a finished pin for positioning to avoid excessive total straightness of the weld.
4, The perfect process
Perfect technology to avoid the situation that the central thinning and thickening of exceed the limitations of restraint and improve the precision of wall thickness.
5, Centering roller
Determine whether the centering roller device can be in place, adjust the middle and opening angles of the relevant core roller, and the opening and closing of all measures is consistent. The center of the core roller must be on the rolling line.
6, Perforated top rod
The perforated ejector rod is generally a thick-walled tube with an outer diameter of Φ108 mm-Φ114 mm and a wall thickness requirement of ≥25 mm and an average wall thickness.
7, Rolling middle line
Ensure that the middle line of the piercing mill is consistent with the middle line of the perforated trolley to prevent "up-rolling" or "down-rolling", so that the tube will maintain its average force during perforation.
8, Rolling things
Rolling on worn heads, guide plates, rolls, etc. must be changed in real time.
9, Rolling equipment
The middle of the roller distance and the lead must be on the rolling line. The middle line of the wrapping pitch and the roller pitch is on the middle line of the piercing and rolling, that is, the upper and lower roller gaps are equal, and the left and right guiding distances are equal. In the production process of straight seam steel pipes, since the primary processing is performed in a hot state, the heating operation is a very important process for determining the quality of products. The key to this heating operation is to uniformly heat the billet to a temperature suitable for processing.
Inappropriate heating will cause cracks, folding, and partial pain on the outer surface of the tube blank. Since the perforation has a great influence on the quality, that is, the temperature during perforation processing is an important condition that affects the quality, the temperature of the blank during perforation processing is generally controlled. The second key to heating operation is to minimize the amount of scale. In particular, when we knead the elbows hot, we start from the number of things and the surface quality of the kneading pipe, and pray for more severe.
