Seamless steel tube wall thickness control is a kind of steel tube which is difficult to produce. The production measures to improve the accuracy of seamless steel tube wall thickness mainly include the following aspects:
1. Tube heating
Heating uniformly prevents the temperature from rising rapidly. Each time heating and cooling keep slow and stable, the maximum temperature is not more than 30 C.
2. Centering roll
Determine whether the centering roll is installed in place, adjust the core holding center, the opening angle of the opening movement and all the same dimensions, and keep the core roll center on the rolling line.
3. Rolling center line
Ensure consistent rolling piercing machine pierces the car center line and center line, avoid "rolling" or "rolling down" to make the pipe keep force uniform piercing.
4. Rolling Tool
For wear head, the guide roller and rolling tool must be replaced in time.
5. Rolling Tool Installation
Rolling from the center of the guide must come from the rolling line. Make sure that the distance from the center line of the guide roll and from the center line is equal to the distance between the upper roll and the lower roll.
6. Perforated mandrel
Perforated jacks usually use uniform thick-walled pipes with outer diameter of 108 mm-114 mm and wall thickness of more than 25 mm.
7. Spindle mill
In order to select the spindle and thick-walled tube, the smaller size of the spindle can be used instead of the solid blank. Thick-walled pipes and solid billets with uniform thickness can significantly reduce the probability of bending deformation of the mandrel, and can effectively improve the accuracy of the thickness of steel pipes.
8. Precision spindle
The slender spindle is relatively large, usually first break the outer diameter with automobile and then weld, or use long material to turn directly. The outer precision control of the mandrel is (+0.1 mm) and the deviation of the straight mandrel is less than 5 mm. When welding, insert the mandrel between the two parts of the finishing positioning pin to prevent the total straightness tolerance from being too large.
9. Process improvement
The process improvement prevents the thinning of the middle wall and increases the thickness beyond the control range, so as to improve the thickness accuracy.