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bmw625
11-18-2015, 02:04 PM
I have a project , I would like to use stainless,but don't have to. 3/4 inch round stock, bent 180 degrees, approx. 3 inch (maybe 2 3/4) radius.

if I use stainless, what alloy would be best ,316 ,304,or??

TIA, brent

RussZHC
11-18-2015, 04:07 PM
"Best" in what sense?

If there are other parameters that need to be met, the type could be important.

As far as I know, the elongation numbers of a particular material, play a role regarding possibility of stress/cracks in the bend itself, if that is the concern [have no clue what the minimum bend would be for that diameter rod] and that info would be different by type of stainless, though might not be by a significant amount.

bmw625
11-18-2015, 09:55 PM
"Best" in what sense?

If there are other parameters that need to be met, the type could be important.

As far as I know, the elongation numbers of a particular material, play a role regarding possibility of stress/cracks in the bend itself, if that is the concern [have no clue what the minimum bend would be for that diameter rod] and that info would be different by type of stainless, though might not be by a significant amount.

stress cracks / ease of bending (cold) is my concern. probably just use cold rolled, just toying with the stainless idea

brent

lakeside53
11-18-2015, 10:03 PM
Heat it up with acetylene to a bright red... bend it. Neither are heat treatable so you won't mess that up.

old mart
11-21-2015, 01:06 PM
18-8 or 18-10 types are so ductile that they would take the bend easily, they can't be heat treated.

portlandRon
11-21-2015, 01:18 PM
Been my experience working with 316 that if you weld/heat it that it is hard to control dimensions.

garyhlucas
11-21-2015, 01:43 PM
I used to bend lots of stainless rod. 304 will bend down to a radius about equal to rod diameter with no problem. 316 will usually crack at that radius.

EddyCurr
11-21-2015, 03:02 PM
A reference that may be useful. Bending is discussed on pp 9-11.
Charts on pp 2-3 describe/compare fabrication properties of various
SS grades.

Note remarks about overbending to compensate for springback,
de-rating equipment capacities expressed in terms of mild carbon
steel, working rapidly and with minimal motion to reduce work
hardening.


Stainless Steel Fabrication (http://www.ssina.com/download_a_file/fabricate.pdf)
Designer Handbook (4-99-5)
Specialty Steel Industry of North America

.

bborr01
11-21-2015, 03:12 PM
Not sure about how ductile 303 stainless is but it is very commonly used for a lot of projects. I'd also suggest using heat before bending. Use an acetylene torch and if the radius needs to be exact bend it around a mandrel.

Brian

bmw625
11-22-2015, 01:17 PM
I used to bend lots of stainless rod. 304 will bend down to a radius about equal to rod diameter with no problem. 316 will usually crack at that radius.

did you use a "hossfeld " type bender ? I'm wanting to bend 3/4 dia. stock 180 degrees, basically a "U" with 5.5 to 6 inches between the "legs"

thanks, brent

bmw625
11-22-2015, 01:19 PM
thanks, that has some good info
brent

Ries
11-22-2015, 03:03 PM
I bend 304 stainless on the hossfeld like that the time, no problem.
I have bent literally tons of the stuff.
It will bend to a radius like that cold, straight from the mill (which means cold rolled, and thus, work hardened).
If you are really worried, you could bend it hot, or, just heat, then quench in cold water, which anneals it to its softest state.
But that will change the color, and, to get it back shiny, you would have to wire brush or sand it.

bend it cold.