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roller expanding SS 304

roller expanding SS 304

roller expanding SS 304

(OP)
Does anyone have any wisdom to share with roller expanding SS 304 tubes 3/8" od. Im looking for tips, comments, gotchas, or anything helpful thanks.

RE: roller expanding SS 304

What is the condition of the 304 ss tubing? Is it annealed? What is the application of the roll joint - function?  

RE: roller expanding SS 304

What's the material and thickness of your tube sheet(s)?  What's the wall thickness of your tubes?

Do you have a torque-control motor and drive?  Do you have any operators experienced with rolling small diameter tubes?  Are you roller expanding only, or will you be doing a strength or seal weld in addition?

-TJ Orlowski

RE: roller expanding SS 304

(OP)
0.035" wall and these are for tube sheets on a 29/64" tri pitch. They are stress relieved u-tubes.

RE: roller expanding SS 304

Quote:

What's the material and thickness of your tube sheet(s)?

Quote:

Do you have a torque-control motor and drive?  Do you have any operators experienced with rolling small diameter tubes?  Are you roller expanding only, or will you be doing a strength or seal weld in addition?

-TJ Orlowski

RE: roller expanding SS 304

(OP)
5/8" thick SS 304 tube sheet and no, no, and hopefully only rolling and no seal welding if we can get away with it.

RE: roller expanding SS 304

It's been a while since we did any 3/8" tubes, but for small diameter ferrous materials, you usually want about 8% wall reduction in the expanded area (I'm assuming your application is low pressure with that tube sheet thickness).  Use a micrometer to check your first couple tubes.

Make sure your mandrel is inserted no more than 1/2" from the front face of the tube sheet.  Get an extra set of rollers.  The manufacturer/distributor of your expander can give more advice about what you want to use to drive it.

Expand the tubes one hemisphere at a time, and start with the largest bend radius.  Don't expand one leg of the u-tube, then it's other leg.  Just expand one whole half, then move to the next half.

-TJ Orlowski

RE: roller expanding SS 304

....and use a proper lubricant on the tube ID surface during rolling.

RE: roller expanding SS 304

We always used parallel rollers instead of tapered rollers for such applications.
For such applications our shop people like to use petroleum jelly, either alone or with a little kerosene, for the lubricant.  We have also seal welded tubes of your size in thin tubesheets. We did this by trimming the tube ends to the shortest length possible and randomly welding the tubes with the smallest weld possible so there is no straight lines in the weld pattern.

RE: roller expanding SS 304

Have you looked at hydraulic expansion?  With small tubes it might work better than rolling.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

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