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Up Topic Welding Industry / Technical Discussions / Location of seam for rolled HSS
- - By jrw159 (*****) Date 05-23-2008 20:57
Hello Everyone,
  I did a check of the material in or yard for seam weld quality. The first place I looked was at some HSS square tubing that we had rolled for a job. The reason behind this was if we had any bad seams it would surely be easy to spot on this material after rolling. While doing this inspection I noticed that most had the seam on the bottom side of the radius. However others had the seam to one side or the other as well as the top. This brought the question to mind of where should the seam be located for the best outcome, or does it even matter? I was thinking that in the past I had heard something about the placement of the seam when rolling but it has been quite some time ago. I will attach a sketch of the part in question.

BTW all seams on this material looked good, and was supplied by a differant vendor than the one we had issues with.

Thanks in advance,
John
Attachment: img-523160334.pdf (28k)
Parent - - By Tommyjoking (****) Date 05-23-2008 22:54
My gut tells me on the inside....simply because you are compressing instead of stretching.  I have got no facts regarding flash welded tube to back that up.  But I would also think if thats a REAl issue the steel plants would have imposed a standard practice many moons ago and as far as I know there is none.  Kudos to you for thinking about it and checking on it.
Parent - - By aevald (*****) Date 05-23-2008 23:14
Hello Tommy, I believe you are right in your thinking of locating the seam to the I.D. of the bend. Another consideration is to be sure that all parts are oriented the same, meaning seam to inside and not allowed to indiscriminantly be located wherever. Besides risking fracture issues the individuals doing the bending will likely experience fairly noticeable repeatability issues for making consistent bends if they don't orient the tubes the same each time. Just a bit more to throw into the mix. Best regards, Allan
Parent - - By jrw159 (*****) Date 05-23-2008 23:58
Allan,
  Thank you for your comment about consistancy. I know under certain circumstances this can really become an issue. My immediate thought was to call out in our vendor specs. a designation for the seam when bending, issued and specified by EOR. I have no doubt in my mind that the vendor will gladly and willingly agree. This will at this point be solely for the sake of continuity.

Respectfully,
John
Parent - - By swsweld (****) Date 05-26-2008 03:35
We just received several 12x8 tube steels .500 wall thickness that was rolled to fit the diameter of a water tower and the seams were randomly positioned by the supplier as we did not specify. I would think that if it was a critical factor the supplier would have asked us to specify before they rolled it as they do this type work everyday. I have no other information to back this up but would like to know if there is a reference to cover this topic.
Parent - - By aevald (*****) Date 05-26-2008 05:10
Hello Tim, I believe the amount of bend or the radius of the bend will have a lot to do with how important the seam orientation is. In your case, I believe you are having your tubes rolled to a fairly large radius so it isn't nearly as important to keep track of the seams. In cases where shops are having to bend tubes that are at the minimum radius it can be very important. Best regards, Allan
Parent - - By swsweld (****) Date 05-27-2008 01:43
Hello Allan. You are correct. Our tank diameter is rather large. The radius and material must be the determining factors on the seam placement. Our material is A500 and the radius is approx. 24'. It has good ductility. One of our owners drew it on auto cad and sent it to the EOR. He approved the design so I hope the bend radius, seam placement and grade of steel are acceptable. I will find out Tuesday. I haven't been too involved in this project until now. I will try to add a few pics of the seam welds. The seams were located on top, bottom, inside and outside. They didn't discriminate.
Parent - - By aevald (*****) Date 05-27-2008 08:00
Hello Tim, look forward to seeing the pictures and also hearing if there are any issues from the EOR, although I wouldn't think there would be. Regards, Allan
Parent - - By swsweld (****) Date 05-28-2008 01:55 Edited 05-29-2008 01:53
I tried to post pics last night but the file was too large. Will try again tonight. The EOR had no issues w/the radius (it actually varies). I didn't speak w/him but inquired w/the guy that did. The TS legs in the pics will be placed vertically and connect at the top of tank.
There is a two layered platform in our shop that will mount to top of tank for Doppler 500. It is 8x8 rolled TS on a much smaller diameter. I haven't been by to take pics of that yet. I will try to get the finished product when complete. Thanks.

img]http://i304.photobucket.com/albums/nn196/swsweld/100_0331.jpg[/img][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0328.jpg[/[IMG]http://[IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0332.jpg[/IMG]i304.photobucket.com/albums/nn196/swsweld/100_0329.jpg[/IMG]IMG][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0332.jpg[/IMG][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0333.jpg[/IMG][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0334.jpg[/IMG]IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0335.jpg[/IMG][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0336-1.jpg[/IMG][IMG]http://i304.photobucket.com/albums/nn196/swsweld/100_0327.jpg[/IMG]

Thanks to John Wrights' photobucket instructions in "What other hobbies do you have?"  and the search feature I didn't have to resort to ctackers' link http://www.glumbert.com/media/baddayoffice and break out the sledge hammer!

Had tag and description on each pic but it didn't take. Satisfied to FINALLY get pics posted.
Parent - By swsweld (****) Date 05-29-2008 02:03
Finally. I couldn't get pics to upload. Too large of a file. Went to Photo bucket.
Not that bright but I am persistent!
Parent - - By jrw159 (*****) Date 05-29-2008 03:19
Nice!!
Parent - - By swsweld (****) Date 05-30-2008 02:18
Here are some pics of 8"x8" rolled TS for the platform that will install on top of tower. This is a much tighter radius than the legs. Roll of paper towel for size reference. Approx 10' diameter. The seams on this TS are on the outside. They look fine.
[IMG]http://i304.photobucket.com/albums/nn196/swsweld/watertower028.jpg[/IMG]
IMG]http://i304.photobucket.com/albums/nn196/swsweld/watertower029.jpg[/IMG]
[IMG]http://i304.photobucket.com/albums/nn196/swsweld/watertower030.jpg[/IMG]
Parent - - By jrw159 (*****) Date 05-30-2008 03:24
swsweld,
  Nice looking results. It sure looks like the location of the seam was not an issue for this project. It seems the seams are in opposite locations on the top as apposed to the bottom.

How did the fit up go? Is consistancy an issue or is this a one time deal?

John
Parent - - By swsweld (****) Date 05-30-2008 23:37 Edited 05-31-2008 01:00
Thanks John. On the legs, the seams were on every side and on the platform they were on the outside. The supplier rolled the TS and left random straight ends on the steel so we had to figure where to cut and splice the steel to get the desired results.
We used Squing backing bars from Robvon to make CJP welds. The fit ups were moderately good not perfect. Sort of like cutting 20 degrees out of a 90 elbow and fitting a pipe to it.
This is a one time deal. The tower is a few blocks from our shop. If the architect wants to make this a product line we would be interested.

Of course that may change after we set the steel next Wednesday :)
Parent - - By jrw159 (*****) Date 05-31-2008 00:40
swsweld,
Based off of the pics you posted, it appears that on the top ring that the seam is on the inside diameter of the ring, and the seam on the bottom ring is on the outside diameter. It would appear that during forming and fit up that this had no ill adversed affects on the overal fabrication.

I was wondering if any differance was noticed between the inside seam and outside seam parts.

By your description and the pic's it would "seam" that there was not. :-)

John
Parent - - By swsweld (****) Date 05-31-2008 01:45
Hello John. The top member is actually a rolled channel. The rolling process left deformation at the end of the rolled pieces. That was random leftover steel that was not used so it didn't affect the fab work.

All the seam welds appear visibly sound. I am going to try get some LPT supplies from another job and check a few spots before we install it.
Parent - By jrw159 (*****) Date 05-31-2008 02:11
swsweld,
  Now I am seeing the full picture. Top is rolled channel and bottom is rolled HSS.

I will say again, nice job.

Let me know how the LP test comes out.

John
Parent - - By jrw159 (*****) Date 05-23-2008 23:49
Tommyjoking,
  My first impression was almost a mirror of yours.
#1-Bottom side-oposite of view-A. I should have included a view-B from the bottom and view-C from the side which would apply to both sides since in this situation I do not believe that left or right would matter.
#2-If it was that signifigant to the outcome of the product, someone who is above me would be making it loud and clear from day one.

Thank you for your input.

Have a great Memorial Day Weekend!

John
Parent - - By swnorris (****) Date 05-27-2008 12:15
Sometimes it's a matter of aesthetics.  Particularly when it's an AESS member. 
Parent - - By Bob Garner (***) Date 05-27-2008 20:36
As an engineer, I would like to see the seam on the inside or outside of the curve.  The walls of the tube undergo shear loading during the bending process which puts a horizontal shear load across the seam weld if it is in the side of the curve.  Putting the seams on the inside or outside subjects them to pure tension or compression, with no differential loads across the seam weld.

Bob Garner
Parent - - By mountainman (***) Date 05-27-2008 20:51
i've always been taught that a good fabricator always hides his seams.

JJ
Parent - By js55 (*****) Date 05-27-2008 21:09
PFI ES 24 is the only doc I know of offhand that deals with tube bending. But I do not remember anything in there about seams.
TPA has a 'Recommended Practice' for Induction Bending of which I don't think applies here.
And just to add my two cents I would have thought the seam should be (if it actually needs to be any place specific, (which as allen stated is probably related to the radius of the bend) on the neutral axis' where the seam would be closest to a point of neither compression or tension.
The intrados will realize not only compression but buckling if the radius is acute enough (which is why we used to fill our pipe with compacted sand when doing hot slab bending-ES 24 has tolerances), and the extrados will realize extensive fiber elongation from the tangent point.
Of course it matters also if its hot or cold bent as well.
Parent - By jrw159 (*****) Date 05-27-2008 20:59
Bob,
  Thank you for your input from an engineering standpoint.

John
Up Topic Welding Industry / Technical Discussions / Location of seam for rolled HSS

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