Key Differences Between 6061-T6 and 6061-T6511

Feature	6061-T6	6061-T6511
Heat Treatment	Solution heat-treated + artificially aged	Same as T6
Stress Relief	No additional stress relief	Stretched to relieve stress
Form	Sheet, thin plate (<0.25”)	Extruded bar, rod
Straightening	Not applicable	Yes, for improved tolerance
Internal Stress	Higher internal stress	Lower internal stress
Dimensional Stability	May warp during machining	More stable; less warping
Weldability	Good	Often better due to stress relief
Availability	Limited thickness and size	Good for extrusions; limited in wide, thick stock