Why does residual air flow when seamless aluminum tubes are squeezed?

- Mar 07, 2019-

When the seamless aluminum tube extruder pressurizes, why does the air remain in the seamless aluminum tube, causing bubbles to appear inside and on the surface of the seamless aluminum tube, resulting in defects that cannot be completely solved, making the seamless aluminum tube change It became a waste. In order to prevent air from entering the seamless aluminum tube, you must find out why the air is being carried in. The following are four main factors that cause internal residual air when squeezing seamless aluminum tubes.

1. Long rod hot shear causes residual air. The shear plane formed when the rod is hot sheared is never perfect and vertical. The industrial seamless aluminum tube is simply subjected to long rod thermal shearing, which causes the bending of the rod to be very severe, resulting in an elliptical cross section of the seamless aluminum tube and a very large round cut. Even with the latest long-bar hot shears, the edge angle of the sheared bar will always be rounded, and these roundings are the best places for air to remain.

2. The upsetting causes the air to remain. Only when the diameter of the barrel containing the aluminum ingot is larger than the diameter of the rod, the rod can be placed into the barrel containing the aluminum ingot. After applying pressure to the column inside the aluminum ingot, the rod is enlarged to the diameter of the barrel, and the gas carried must be discharged. The gas is not discharged, and it remains in the aluminum ingot and eventually becomes a bubble.

3. The air remains due to the contact of the two aluminum rods. Because the surface of the two short studs is essentially flat, the probability of carrying in and out of the air is very small. The quality of the saw directly interferes with the amount of air carried between the two short studs. At present, there is a high-tech that prevents the two short columns from coming into contact and eliminates the possibility of air ingress.

4. When squeezing the seamless aluminum tube, it is necessary to avoid the entry of air, so as to avoid the situation of air residue, which is a kind of defect in the post-processing.