Structural Steel Cert

[crzdriver]

I'm finally getting my structural cert, and I had a few questions before I dove off into the deep all by me onesies. I'm doing the unlimited thickness on 1" plate. Vertical up, 1/4" root with 1/4" backing plate and 60 deg bevel, 8" long.

I'm worried about warping. Do they care, or should I make an effort the jig the pieces to keep them from shrinking toward the weld?

Should I preheat the plates, or are they just mostly looking for clean welds on the inside? I'm going to weld, grind to shiny, weld, grind, etc.

I've never done a weld with a backing plate or a root quite that wide. Should I make one big sweeper root, or run one for each plate, concentrating on the backing?

Lastly, are sweepers better all the way out, or should I stack my beads? I'd prefer to stack them to prevent shrinkage stress, but what matters more?

I figure a lot of you guys have done this, and maybe there are some radiographers amongst you. Thanks for the info.

[Fat-Fab.com]

I'm finally getting my structural cert, and I had a few questions before I dove off into the deep all by me onesies. I'm doing the unlimited thickness on 1" plate. Vertical up, 1/4" root with 1/4" backing plate and 60 deg bevel, 8" long.

I'm worried about warping. Do they care, or should I make an effort the jig the pieces to keep them from shrinking toward the weld?

Should I preheat the plates, or are they just mostly looking for clean welds on the inside? I'm going to weld, grind to shiny, weld, grind, etc.

I've never done a weld with a backing plate or a root quite that wide. Should I make one big sweeper root, or run one for each plate, concentrating on the backing?

Lastly, are sweepers better all the way out, or should I stack my beads? I'd prefer to stack them to prevent shrinkage stress, but what matters more?

I figure a lot of you guys have done this, and maybe there are some radiographers amongst you. Thanks for the info.

Warping not your issue just make the weld.

Preheat is called for any time the base metals are under 70*F

On the root make sure to tie all three together weather that is done in a single pass or two smaller ones is up to you. I run one pass right down the center then Ill grind one toe of the first pass and rune one up it then grind the toe on the other side of the frist pass and fill it then start stacking stringers.


TJ

[phaxtris]

dont rely on that grinder, you may not be able to use it depending on the governing body, try to run your beads in a fasion that does not create possible slag inclusions, or tight spots at the toe of the weld (that could lead to slag inclusions or incomplete penitration)

those plates always warp, the inspector knows that, and the governing body knows that, warpage is not a concern

other than that just fill it up, those tests with backing plates are a breeze, i wouldnt be to worried

[Bert]

I did my cert about 6 months ago, like the guys posts, don't worry about the warpage. During school, some guys made a strongback, our union teacher just had us fully weld the backing plate on both sides...did just fine. We used 3/8" plate for the backing plate...I did 2 stacking beads for the root, then swept the rest of it. Teacher said they do that more in the field, 'cause it's faster then stacking stringers. Don't need to preheat (only tip on preheating, was when one of my jouneyman said I had to preheat to weld 1/4" with my MM135. I asked, and they let me have the x-rays. Still haven't framed them on my wall yet

[Bert]

you didn't mention about your overhead?! We had to do vert and overhead. Any grinding had to be done "in position"....

[crzdriver]

Thanks for all the info! I'll get it done by next week and let you guys know how it turned out.

[Bert]

GOOD LUCK!!! Came home late! Did my MIG test for work, wish me luck too!