The uneven wall thickness of the hot-rolled pipe is the key to the hot-rolled one-time hole. The uneven wall thickness of the capillary hole is likely to be caused by the following three levels of factors.
1. The uneven heating of the pipe material is generally referred to as the yin and yang face.
When the pipe material is heated in the inclined hearth furnace, if the material is not drawn frequently, half of the pipe material will be "cooked" and half "raw". When the hole is broken, the frictional resistance will be different, resulting in uneven wall thickness.
2. The hazards of the shape and position of the top edge.
The top edge is applied too much, and part of the "table" is fused and deposited. The aspect ratio of the "table" is uneven, which means that the top edge is not round, which will harm the uneven wall thickness; if it is more serious, it will continue to scratch the capillary tube. Surface layer, resulting in an inner "heavy skin". After the top edge, it will also compromise the uniformity of the wall thickness.
3. The small chain vibrates.
The perforator is assured that the rollers are not adjusted in time, and the small chain cannot be "clinched" smoothly, and the small chain vibrates, resulting in uneven wall thickness.
Second, cold-drawn steel pipes, cold-drawn seamless pipes and thick-walled pipes are asymmetrical incentives:
1) The inclination of the front of the pipe material, the excessive bending, and the skewed hole of the pipe material can easily lead to uneven wall thickness at the top of the seamless steel pipe head.
2) The widening index is very large when the hole is broken, the speed ratio of the hot-rolled strip is too high, and the cold-rolling is unstable.
3) The unstable steel throwing of the puncher can easily lead to uneven wall thickness at the end of the capillary tube.