Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Minimum Bend Radius 0.75" OD SS, .065" wall thickness
(OP)
Trying to find a minimum bend radius on a stainless steel pipe. I know the rule of thumb is 2xOD usually, but it would be nice to get a more accurate min bend radius. Also, I have not done this in a while and not sure if min bend radius is the centerline radius or the inside tube radius they are talking about when they talk about min bend radius??? Thanks





RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Cheers,
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
http://www.detroittubeproducts.com/die_inventory.h...
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Another aspect to consider is the cost of going to smaller diameters. At a large bend diameter, you can get away with bending the tube with relatively simple mandrels. To achieve very tight radii without excessive flattening and wrinkling, the bending shop will have to start using more advanced techniques such as packing the tube with another material to resist flattening. These more advanced techniques all come at a cost.
Cheers,
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
If YOU "have to" use the smaller radius for some particular (expensive!) but valid reason, require that special small radius in the dwg and bid and in the pricetag.
IF you do not absolutely-positively-have-to-use-it need that small a radius, USE THE BIGGEST (STANDARD) RADII YOU CAN. It is cheaper. Easier, more likely to be successful. Do NOT order a special size unless you really, really need.
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Their guidelines may provide some help. Swagelok for example has tables for bend radii depending on tube OD.
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Excessive thinning is the most common problem with 180° 'return' bend pipe fittings. Thus the mfr starts with a 'tube' much thicker than the pipe schedule, and bends the tube. And usually leaves the ID mismatch for the pipefitter to grind it down until a satisfactory fitup to the pipe can be obtained.
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
A bend radius of 2 or less will probably require INTERNAL guiding (there is tooling for this, if the bend is near one end), or another means (sand filling with plugged ends etc.) to reduce the tendency for the tubing to go oval or collapse inward at the bend. External guiding alone will be insufficient.
A bend radius of 1.5 could probably be done hot, or if internal guiding is possible.
RE: Minimum Bend Radius 0.75" OD SS, .065" wall thickness
Of course these sets are a bitch to box since row 1 is larger than row 3 in some cases.
When you go tighter than r=2d you usually have to relax both the wall thinning and ovality requirements. These can be ugly bends.
On ubends we usually use mandrels up through about r=3.5d.
And yes we mandrel bend tubes that start 120' long.
In high fatigue applications (aerospace) they require mandrel bends (ovality less than 3%) and in general they wont use a bend tighter than r=3d
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P.E. Metallurgy, Plymouth Tube