ALUMINUM GLOSSARY - Airoldi Metalli

The amount of saleable aluminum in the form of extrusions obtained from a press run. The recovery ratio
is the proportion of such saleable metal to either the original ingot or to the ready-to-extrude billet, as the
case may be.
Reduction
In metallurgy, the electrochemical process by which purified alumina (aluminum oxide) is broken down
into its constituents, freeing metallic aluminum.
Reduction Ratio (Extrusion Ratio)
The comparison of the cross-sectional billet area to total cross-sectional area of the resulting extrusions.
This is determined by the cross-sectional area of the container or upset billet divided by the crosssectional
area of the combined die openings.
Refined Aluminum
Aluminum of very high purity (99.950 percent or higher) obtained by special metallurgical treatments.
Reflectivity
The ability of a surface to reflect light and other electromagnetic radiation. Aluminum has high reflectivity:
80% or more for visible light, and 90% or more for infrared radiation.
Reheating
Heating metal again to hot-working temperature. In general no structural changes are intended.
Relieved
Aperture or opening in a die where its entrance is smaller than the exit.
Residual Stresses
Those stresses set up within a metal as the result of non-uniform plastic deformation which may be
caused by drastic temperature gradients in quenching.
Resilience
The ability of a material to regain its original shape after distortion. Aluminum is a resilient material.
Resolution (of a measuring instrument)
The smallest unit of measure that an instrument is capable of accurately and repeatedly indicating.
Restrictor Bumps (dams, speed bumps)
A bulge or hump in the die's metal flow area serving as a means of controlling the flow or feed of metal.