← Learning Center Glossary
Aluminum extrusion glossary
Plain-English definitions of the terms you’ll meet specifying and buying aluminum extrusions.
0–9
- 6061
- A stronger structural alloy, better for load-bearing, machined, and welded parts.
- 6063
- A common architectural extrusion alloy — extrudes into fine, thin-walled profiles and anodizes well.
A
- Alloy
- Aluminum combined with other elements (e.g., 6063, 6061) to tune strength, finish, and workability.
- Anodizing
- An electrochemical finish that thickens aluminum’s oxide layer into a hard surface that won’t peel.
B
- Billet
- The solid cylindrical block of aluminum that is heated and pushed through the die.
C
- Circumscribing circle
- The smallest circle that fully contains a profile’s cross-section; a smaller circle generally means lower cost.
D
- Die
- The steel tool with a shaped opening that gives the extrusion its cross-section.
- Die line
- A faint longitudinal line on a profile’s surface, a normal artifact of the extrusion process.
E
- Extrusion ratio
- The ratio of billet area to profile area — a measure of how much the metal is squeezed.
H
- Hollow / semi-hollow / solid
- Profile classes — solid has no enclosed voids; hollow encloses one or more voids; semi-hollow partially encloses one.
M
- Mill finish
- Aluminum’s natural, uncoated surface straight off the press.
P
- Powder coat
- A durable color finish applied as electrostatic powder and cured with heat.
- Profile
- The extruded shape — the cross-section produced by the die, in a continuous length.
Q
- Quench
- Rapid cooling of the profile as it exits the press, part of setting its properties.
S
- Secondary operations
- Steps after extrusion — machining, fabrication, finishing, assembly — that turn a profile into a finished part.
- Stretching
- Pulling the cooled profile straight to remove twist and bring it into tolerance.
T
- Temper
- A designation (e.g., T5, T6) describing how an alloy was heat-treated for strength.
- T-slot
- A profile with slotted channels for modular framing and connectors.
W
- Wt/Ft
- Weight per foot — the weight of one linear foot of a given profile.
Need help specifying a profile?
Talk through your drawing with our team before the die is cut.
Request a quote