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Up Topic Welding Industry / General Welding Discussion / Bead placement on Single bevel
- - By momo Date 06-05-2008 20:59
Hi guy's i'm new here and have a question. I'm taking a test tomorrow, 3G and 2G using 1/16th Dual shield, CO2 backing gas. The joint is square grooved, 1'' and the root with backing is 5/8th. And FYI, the square edge is above, so no bead support on the bevel(in 2G). Here's the question. The welds started beautifully. I ran two beads for the root, let it cool and then proceeded to weld two more. Still looking good. I'm trying to give it as much time between passes as i can, but my instructors weren't going to stick around till 11 for me to give it the time it needed. Basically, the last bottom pass sagged so bad it obviously messed everything else up, my cover passes were atrocious. I started the weld on the bottom edge so as to give the top bead more support. Should i have started on the top edge instead? Or did the bead sag because there was simply too much heat in the joint itself? Oh i was using 32V with a wire speed of about 300.
Parent - - By pipewelder_1999 (****) Date 06-05-2008 23:36
Normally the joint would be done with the square edge down but it is possible either way. If I am running a process or heat that is likely to roll over on the 1st bead I will leave that bevel underfilled more than the rest of the joint on the last layer before capping. Also, don't be afraid of running different size beads as needed to keep things evened out.

That bottom bead that is used to buil off of on the cap is a very hard to keep from having overlap or at least a real sharp re-entrant angle at the bottom toe. To minimize that I will try to leave a bottom edge of the plate there before capping. I dont worry a great deal about keeping the final layer flat as much as making sure there are no individual grooves or valley on the underlying layer that I may have a hard time tying into.

I will try to make a sketch to show what I am talking about.
Parent - - By jrw159 (*****) Date 06-06-2008 00:07
pipewelder,
  If memory serves me correct, you have posted a diagram for this before. It is nicely done and well explained. I look forward to seeing it again.

jrw159
Parent - - By pipewelder_1999 (****) Date 06-06-2008 00:24
Got a new one working for this post.
Parent - By jrw159 (*****) Date 06-06-2008 00:27
Nice. I can not wait to see it.

jrw159

Heads up momo, this will be good.
:-)
Parent - By jrw159 (*****) Date 06-06-2008 00:13
momo,
  Welcome to the 4um. LOL

This is the best place I know of to get information and opinions regarding the welding industry.

jrw159
Parent - - By pipewelder_1999 (****) Date 06-06-2008 04:41
Here is a video that describes one of the ways I handle the overlap situation on a horizontal weld. The audio is a little rough and I am sure there are many other things that could be added.

http://weldingdata.com/horizjoint/horizjoint.html
Parent - By DaveBoyer (*****) Date 06-06-2008 05:16
If a picture is worth a thousand words, a video must be worth well over a million.
Parent - - By jrw159 (*****) Date 06-06-2008 13:44
pipewelder_1999,
   Very nice, my friend. The audio is not really that bad.

jrw159
Parent - - By momo Date 06-06-2008 20:56
Hey guys thanks for responding! lol. I took the test this morning. And i passed both of them 2G and 3G! My biggest worry was cold rolling on the horizontal plate, i had been having a problem with it when i practiced. For whatever reason, it didn't happen. So, maybe in a couple of weeks, i'll be a ship builder! Yahoo!
Parent - By jrw159 (*****) Date 06-07-2008 01:09
Good luck with it. :-)

jrw159
Up Topic Welding Industry / General Welding Discussion / Bead placement on Single bevel

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