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Any meatl experts in/up? I'm making some aluminium brackets. Getting the shape laser cut then need to bend them, about a 15mm rad in a couple of places. Ideally when bent I want them to stay that shape and I'd like the whole thing to be reasonably strong and stiff. Currently the bent part will be 19mm wide and 5 or 6mm thick. I've just done a test with a random bit of 1/4" extrusion. Cracked it on the first try, annealed it and tried again and that worked. Happy to anneal if it needs it (pretty basic plumbing gas torch and marker pen method). My laser cutter offers the following grades: 1050, 2024 T3, 5083, 5251, 5754, 6061 T6, 6082, 7075, Alloy 400, Hastelloy C-22, L61, L82. So, which one to go for? Only other processes are knocking off the corners and tapping a couple of holes.
If you need to anneal it to bend it you need one that can be heat treated after to return it to strength. 6061 T6 is one such - you'll need an oven suitable for heat treatment.
Alternatively you need an alloy that is malleable enough to be bent to the shape you wish without annealing or cracking. Sorry, I can't pick one from your list.
i've forgotten most of that stuff but pretty sure anything that demands a bend with radius 3x metal thickness is a design problem. (that's a full stop)
I can tweak the rads if it is close to the limit although its not a high stress part.
Leaning towards the 5251 having done some reading
[i]
Aluminium alloy 5251 is a medium strength alloy possessing good ductility and therefore good formability. Alloy 5251 is known for work hardening rapidly and is readily weldable. It also possesses high corrosion resistance particularly in marine environments.
Applications
5251 is typically used in:
~ Boats
~ Panelling and pressings
~ Marine structures
~ Aircraft parts
~ Vehicle panels
~ Furniture tubing
~ Silos
~ Containers
[/i]
What's it for? Can you not use something like 304 (or maybe 316) stainless?
It would be much happier being bent and you could use a much thinner gauge to get the same strength?
Rather than getting it laser cut and bending it yourself, it might just be easier to get a sheet metal fabricator to do the whole lot.
I'd have thought by the time you've paid for the laser cut bits, it wouldn't be much more for a fabricator to bend them...
6082-T6 is my go-to grade. It works well, it's cheap & anodises easily. 6061 is pretty much identical, but more common in the US & Far East.
why the need for the bend 5083 will weld and survive a fair bit of aggro without heat treatment
is a critical part?
Nothing safety critical. Needs a gentle bend to form a hook. I'm happy enough that I can bend it. Just want it to not crack or bend back when under its small load. As I have choice of alloys I just wanted the best of the bunch. The laser cutting is only a few quid per part and I can do the bending in my shed.