Can any one name this process

M

Mutt

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this is a piece of 18g mild steel,24" long, rolled into a 2.500" o.d. tube, ends overlapped 1/4" and then it is what I would call "roll seam welded" Each of these lines is a "weld" Can any one clue me in on how this process works? Is there company still around that can do this process? I need 25 of these tubes.
Thanks
Mutt

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I'm pretty sure it's a form of spot welding. There's an arbor inside the pipe, connected to one side of a high current power supply. A wheel, connected to the other side of power, runs along the seam, applying high pressure and current to a very small area. From the looks of the seam, the wheel has very shallow "teeth," probably to help concentrate current in a small spot and to insure traction. No idea who does this, no idea of what the exact nomenclature is.
 
Hi Mutt,
what application is the tube being used for?
could another form of tube be used instead of the seam welded tube?

i found a youtube video of some larger diameter pipe being seam welded.
the process would be similar in smaller diameter tube, though the machine would be a bit smaller.


Resistance welding also comes to mind as a process
 
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I have seen it where they custom make long pieces similar to what they do for steel where it is heated to a malleable state bent and welded together all as one process, Not sure why they do not just extrude it at time when that is done but have had some long pieces of it, that were done that way. The one Ulma Doctor found looks like some I have seen on stove pipe pieces and AC ducting. Where is all custom made. would be a good one to send in to the HOW its made show.
 
As the question has already been asked; What's the application? There are plenty of sources for 2.5" OD tube with a .050" wall thickness. Most tubing tubing manufactured today is joined at the seams with some type of flash welded, resistance welding process but the seams are butt welded with the flash removed on the outside and sometime on the inside, similar to pipe. It's difficult to tell looking at the photo but it seems the outside is flush so the seam is offset to accomodate the overlap. I could go on naming the different processes used to join tube and pipe seams but my suggestion would be to contact your nearest steel supply house or maybe a pre-production processor who would cut the pieces to length for you from lengths of 2.50" tube.

It takes a stout roll to form/roll 18 gauge steel into a 2.50" cylinder, even at 24" long and the welding is the simple piece in the process.
 
URL for the video that Mike posted is
Might it be worth while to get in touch with the guy and ask where he took it, whether they could do what you need, etc.?
 
kvt said:
I have seen it where they custom make long pieces similar to what they do for steel where it is heated to a malleable state bent and welded together all as one process, Not sure why they do not just extrude it at time when that is done but have had some long pieces of it, that were done that way. The one Ulma Doctor found looks like some I have seen on stove pipe pieces and AC ducting. Where is all custom made. would be a good one to send in to the HOW its made show.
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Most tube and pipe is formed using the cold rolled process and the flat strip coming off a coil is formed with rolls (dies) that form the tube progressively to the shape desired and as the seam comes together it is flashed welded.

Ulma Doctor's video is a rolled seam resistance welding process and just one of the many types of resistance process (aka spot welding) used to join metal when there is a lapped seam.
 
Thanks for y'all's input. Looks like Ulma found it. That's the correct process. I worked at a conveyor manufacturer one time and they had one of those machines. I restore antique motorcycles from the 1930's to 1950's. In my business, these things got to be exact. Otherwise, it's just another aftermarket part. I'll see if I can get in touch with the dude that made that video and see where that place is.
 
I would say that some 2-1/2" OD muffler pipe material should fit the bill. Of course now days, its all ERW as Rustrp has mentioned. And some ERW material will have similar patterns. The "stitching" is just the traction roller feeding the material thru the resistance welder.
 
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