According to the Aluminum Associations standards and data:
T_51 Applies to plate and rolled or cold-finished rod or bar, die or ring forgings and rolled rings when stretched the indicated amounts after solution heat treatment or after cooling from an elevated temperature shaping process. The products receive no further straightening after stretching.
Plate 1 1/2 % to 3 % permanent set
Rolled or Cold-Finished Rod or Bar 1 % to 3 % permanent set
Die or Ring Forgings and Rolled Rings 1 % to 5 % permanent set
T_511 Applies to extruded rod, bar, profiles (shapes) and tube and to drawn tube when stretched the indicated amounts after solution heat treatment or after cooling from an elevated temperature shaping process. These products may receive minor straightening after stretching to comply with standard tolerances.
Extruded Rod, Bar, Profiles (Shapes) and Tube 1 % to 3 % permanent set
Drawn Tube 1/2 % to 3 % permanent set
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Typical Physical Properties:
Density: .098 lbs/in3
Average Coefficient of Thermal Expansion (68 - 212 oF): 13.1 x 10-6/ oF
Melting Range (Approximate): 1080 - 1205 oF Temper: T651 - Stress relieved by stretching.as mentioned above...
Extruded ALUMINUM RECTANGLES Under 1?2” Thick – 6061-T6; 1?2” Thick & Over – 6061-T6511.
This is the main difference in Square & Rectangular Bar for example.