The cause of aluminum profile bubbles

1. The gas or extrusion process inside the ingot is involved in the air, after extrusion or subsequent heat treatment expansion, in the extrusion products bulging and forming, as a circular single bulge called bubbles, as a large piece of torn skin.

The reason for the occurrence

1. During the extrusion process, the metal is involved in the air inside, and the temperature of the drum lining and ingots is uneven. The metal on the surface of the ingot is involved in the extrusion flow, forming skins or bubbles along the front elastic zone. And another reason is that the high temperature and high pressure gas pressed into the metal surface after the ingot is thick, or the gas content inside the ingot is too high, and diffuses into the surface when heated.

2. The inside of the ingot originally contains gas or the inside has cracks and pores or unclean.

3. The size of the extruded barrel and the extruded pad is not well matched

4. Squeeze cylinder lining long-term not clean, extrusion cylinder or extrusion pad is not clean, oil and so on.

5. The residue is separated cleanly

6. Atmosphere during heat treatment (water vapor, oil and dirt absorbed from the sink below in the case of vertical furnaces, etc.)

Countermeasures

1. The heating temperature of the ingot is uniform, and the extrusion temperature is reasonably controlled. Gradient heating (high front-end temperature) and secondary exhaust process are used.

2. Use the cleaning pad to regularly clean the squeeze cylinder lining dirt, regularly check whether the internal size of the oval or drum belly situation, such as exceeding the requirements of the procedure should be timely correction of the shape of the extrusion cylinder, or replace the poor extrusion pad.

3. Use suitable extrusion mold between (residual material separation is better, magic block cut-off scissors, keep the tool clean)

4. Increase the thickness of the residual pressure

5. Full degassing should be carried out during the smelting process.

6. Control the heat treatment environment of the extrusion profile.