Extrusion Ratio

The extrusion ratio is defined as the ratio of the cross-sectional area of the extrusion container to the cross-sectional area of the extruded product. It is a critical parameter in the extrusion process and a key indicator of the difficulty of extrusion. Generally, a higher extrusion ratio results in greater deformation of the product and requires higher extrusion force—meaning the process is more difficult; in extreme cases, this can lead to the phenomenon “jamming”. Conversely, a lower extrusion ratio results in less deformation and makes extrusion easier. However, if the extrusion ratio is too low (e.g., < 8), the limited deformation may allow the cast microstructure still exist in the final product, thereby affecting its strength performance.

Refer to the table for the typical extrusion ratio ranges for various aluminum alloys

Alloy	General extrusion ratio	Maximum allowable extrusion ratio	Minimum allowable extrusion ratio
General soft alloys	20～120	≥200	>10
Medium-strength alloys	15~80	≥150	>8
High-strength alloys	12~50	≥80	>6