How to solve the problem of tissue streaks generated during aluminum extrusion

Organizational streaks are band like patterns that appear in the extrusion direction of aluminum alloy extruded parts due to uneven organization and composition. Most of them appear in the thickness variation area, which can be identified through corrosion and anodizing treatment. When changing the corrosion temperature, the band like patterns sometimes disappear or their width or shape changes. Mainly due to uneven macroscopic or microscopic structure of the ingot, insufficient homogenization treatment of the ingot, or incorrect heating system during extrusion processing.

Solution to organizational streaks:

1. Choose an appropriate shape for the outflow chamber.

2. Dig a pit on the end face of the mold. After squeezing, the excavated metal and residual pressure are removed together and not left in the pit.

3. Dig a part of the shoulder surface of the mold and turn sliding friction into internal shear friction.

4. Adjust the diversion chamber or sizing strip.

5. The cast billet needs to undergo fine grain refinement treatment, and it should be uniformly and rapidly cooled during solidification.