? heat bending stainless angle

I recently saw an interesting DIY way of bending big sections of
structural steel with just an OA torch. This is done on the piece
before it's connected to the building. (The ends need to be free to
move.) They mark off a wedge on the piece with the wide end of the
wedge facing the inside of the desired bend. They heat just the wedge
area with an OA torch so that it gets red hot. The nearly molten
metal in the wedge is constrained by the surrounding unheated metal so
it deforms, then as it cools it pulls togather to make a slight bend.
This is repeated along the length of the piece until the desired curve
is obtained.
But this was done on a big structural steel angle. Would the same
technique likely work with 1 x 1 x 1/8" type 304 stainless angle? I
need to bend it the "hard way" e.g. with the leg pointing to the
inside of the curve. Warping in unintended directions would be
unacceptable. Slight changes in angle leg thickness would be OK.
--zeb
Reply to
Zeb Kagloonpop
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The 300 series of stainless is subject to intergranular corrosion when heated through a range of 800/1500 degrees F, so the repeated heating and cooling would likely create certain problems in the metal. If it is strictly for cosmetics, you may get by fine, but you may alter the structure of the material enough that it could lose some of its properties, perhaps creating a possibility of failure under load. Dunno.
It may respond even better than carbon steel to the heating and cooling considering it has a rather high coefficient of expansion. Again, dunno. I've never tried it.
Harold
Reply to
Harold & Susan Vordos
Itty bitty angle like that is going to be very difficult to bend as you describe. You will probably end up with a very crooked piece of stainless. Applying heat to big structurals is more of an art than a science. It is described in the book "Flame Straightening Technology" by John P. Stewart. Self Published, and available from the author.
I often bend 1x1x1/8 cold in the vise to gentle curves. You can tweak it quite a bit if you try. Of course, this is one of those situations where the right tool for the job makes it easy. I bend stainless angle all the time cold with a hossfeld bender, and with powered angle rolls. I know- those cost money. But they work.
I also forge quite a bit of stainless- get it hot in a forge, bend it, and hammer out any wrinkles or distortion with a hammer on the angle. This works just fine. Bending angle hot in a hossfeld, and then hand hammering it, is quick and works well, even for very tight curves. Ditto flat bar the hard way. I have never noticed any appreciable lessening in strength in stainless after being forged. I am not making space shuttle parts, but I dont think you really need to worry about this for most applications.
Reply to
Ries
A wander through Google allowed me to relocate the following, posted by Ernie back in 2000:
# I will always remember Francis's demo at the Birmingham ABANA # conference. # # It was 100 degrees in the shade so nobody wanted to light up # a forge. Francis stood surrounded by over 100 smith, some with # many many years experience and he promptly stunned every single # smith in the crowd by demonstrating how to cold bend angle iron # to any shape with only a bending fork and a post vise. # # It was amazing. # He used 1/2" x 1/2" x 1/8", so he didn't have to heat it, but # watching him create a perfect circle with the flange in, and # then with the flange out, was awe inspiring. # # Bend the wrong leg the wrong way, then bend the right leg the # right way. # # So simple. # # He said he learned it from some members of the "Benders" union # who used to bend angle iron tracks for factory assembly line tracks. # # -- # STAGESMITH - Custom Metal Fabrication - Renton, WA, US
Hope that helps, --Glenn Lyford
Reply to
Glenn Lyford
On Mon, 21 Jun 2004 12:28:20 GMT, Glenn Lyford vaguely proposed a theory ......and in reply I say!:
remove ns from my header address to reply via email
I have a broken left knee and a straight piece if angle iron....
Reply to
Old Nick

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