Bend R alum 6061-T6

[tmschrader]

Does anyone have another bend radius chart for aluminim.
Looking for safe bend radius for 3/8 6060-T6.

The chart in the back of the Reynolds alum catolog lists 4 1/2x thickness for 90 deg bend, for 6061-t6, but I would like a second source before we buy the tooling/dies. Is R=1.6875 seem to conservative or not enough.

 

[ornerynorsk]

Are you speaking of solid or tubing? I have routinely bent 3/4 x 065 tube (6061T651) at a 2 inch centerline radius with no problems.

 

[tmschrader]

the question concerns 3/8 pl 6061-T651

 

[kenvlach]

I have several references with the same range of values. Also, some info on heating to allow a smaller radius or for stress relief:

The Alcoa Structural Handbook, Table 11, for 90^o cold bends and t = 3/8”, gives a radius range 3.5t to 5.5t. Footnote reads
“Minimum permissible radius over which sheet or plate may be bent varies with nature of forming operation, type of forming equipment, and design and condition of tools. Minimum working radius for a given material or hardest alloy and temper for a given radius can be ascertained only by actual trial under contemplated conditions of fabrication.”

In the Supplementary portion of the above book, ASCE Paper No. 970, ‘Specifications for Structures of Aluminum Alloy 6061-T6,’
“Sect. 1-3. Heating.—Structural material shall not be heated, with the following exceptions:
a.—Material may be heated to a temperature not exceeding 400^oF for a period not exceeding 30 min to facilitate bending….”

I would add, should you consider heating, that 400^oF exceeds the age hardening temperature (350^oF for 6-10 hours) for this alloy, so a lower temperature would be desirable. Ideally, the stress relief imparted by the heating would cancel the brittleness from the work hardening of the bending, so you could produce a final product w/o loss of mechanical properties at the bend.

 

[tmschrader]

Thank you for your time