Production control of precise steel tube with wall thickness is a difficult process. Improving the accuracy of precise steel wall thickness mainly includes the following aspects:
1. Heating pipe, heating should be uniform, fast increase the temperature prohibition. Heating and cooling each time to maintain stability.
2. Centering roll, open the same size of the centring roll to determine the installation position, surround the central core volume to adjust the relevant opening angle and various actions.
3. Roll the center line to ensure that the center line of the rolling machine is consistent with the center line of the rolling punch, so as to avoid rolling up and down "the tube keeps straight line.
4. The wear-out rolling tools of head and other rolling tools should be replaced in time.
5. In the installation of rolling tools, the central leader must ensure that the distance between the center line of the center line and the piercing of the rolling guide roll is approximately equal to the distance between the upper and lower rolls.
6. The uniform thick-walled pipe with an outer diameter of 108 mm-114 mm and a wall thickness of more than 25 mm is usually used for piercing punches.
7. Mandrel mill, mandrel selection and thick-walled precision steel processing, smaller size mandrel can be used to replace solid billet. The uniform thickness of the wall pipe and solid blank can significantly reduce the probability of bending deformation of the mandrel, and can effectively improve the accuracy of the wall thickness of the steel pipe.
8. Precision spindle, spindle slender length is relatively large, generally used first car and then drill out the outer diameter weld, direct elongation or forming materials. The outer precision of the mandrel is controlled (+0.1 mm) and the deviation of the straight mandrel is not more than 5 mm. Welding, finish insertion of a pin between the two parts of the spindle, total deviation can prevent the direct result of excessive welding.
9. Process improvement and process improvement to prevent the thickness of thin wall of intermediate precision steel from increasing beyond the control range.