13. Surface quality

The surface quality of an extruded aluminium profile depends on a number of things: the condition of the die, the design of the profile, production conditions, and the choice and quality of the alloy.

Hydro has an independent classification system for evaluating surface quality, or finish. The six classes satisfy the standard requirements of different product groups. Always contact Hydro for advice on which class is best suited to your product.

Various types of surface defects, such as extrusion lines/zones that are process-related, can be recognized and occur when the profile emerges from the die. These can always be expected. They occur to certain extents in all surface classes and give the typical “extrusion appearance.”

Hydro’s production standards minutely detail the requirements that apply to each surface class.