8 Precautions for seamless pipe forming

Forming and sizing of seamless pipes, some hole design and adjustment methods will directly affect the quality, so we should pay attention to the following eight points when handling the forming of seamless pipes:

1. Before there is no perforation, the hole shape of each rack should be adjusted, and the size of each pass should be measured to ensure that the seamless steel pipe enters each rack stably. In the adjustment, the force should be balanced, and it should not be forced to deform on one frame, so as to ensure the stable and uniform change of the raising angle;

2. Traditional roll forming skills, with single radius, double radius, plus two, three, four or five rolls kneading rolls, two or four rolls sizing to ensure the forming quality. This traditional roll forming technology is mostly used for rectangular tube units with a diameter less than φ114mm;

3. In the production of seamless pipes, control and adjust the equipment errors of the forming and sizing machine bases and the amount of roll bounce, so that even the more old-fashioned units can produce fine high-quality steel pipes;

4. The roll forming skills of the United States, the CTA forming skills of voestalpine, the FF or FFX flexible forming skills of Nakata, Japan, etc., can ensure the shape of the welded joint after forming and good appearance quality, and are suitable for standard A wider range of seamless pipes;

5. During the adjustment process of the unit, first of all, it should be ensured that each pass of the vertical center line is consistent, and the center is used as the base axis to find the positioning scale and the center sleeve. ) is a straight line, and can not show curve beating;

6. In order to reduce elastic deformation, 2 to 3 passes are added to the processing deformation of seamless pipes than the general rectangular pipes;

7. In the deformation structure, the initial deformation point of view should be reduced to ensure a stable bite, the central curved point of view should be appropriately increased, and the rear deformation should be appropriately reduced. Adding deformation passes not only reduces the deformation force, but also makes the strip There is an opportunity to release the surface stress, so that the gradient of the surface stress increases slowly, which can prevent the seamless pipe from cracking;
8. Various forming skills have different advantages and disadvantages, and are suitable for different conditions. According to the use of seamless carbon steel pipes, careful consideration should be given when selecting equipment, and different forming methods should be selected.