To fill or not to fill....

Date 12-15-2003 04:14

B-U2a is a SMAW joint design. I think you meant B-U2a-GF. Table 3.7 Prequal. requirement state that th max fill pass thickness for FCAW is 1/4". I didn't see the other post.

Hope this helps.

Brian J. Maas

By jwright650 (*****)

Date 12-15-2003 18:57

Hi Brian, Hi Chet,
Yes, Brian you're right I didn't spell it out far enough....
....[it should have read B-U2a-(G) or (F).
Guys, I would rather see the 3/8" groove filled in at least three passes too, but I was just figuring for arguement sake. Mathius' teacher wanted to see it done in two passes, so I was looking at this from other angles to see if it were possible by code. Look back at that Table 3.7 and in the column above Max Fill pass, there is a column for Max Root pass which says in the flat position under GMAW/FCAW [3/8"] and under the vertical postion w/ GMAW/FCAW [1/2"]. Then there's the note#4 which directs you back to the para 3.7.2.

So, If you were to fill this groove in one pass wouldn't that qualify as a root pass?
John Wright
PS, I figured it might not get seen, so I just restarted the question over because it would get lost in all those posts over on the other board.

By CHGuilford (****)

Date 12-15-2003 15:52

I'd say it depends on the filler metal size, amperage, and position of welding. But ordinarily, I'd want to use 3+ passes to fill a 3/8 test groove. Just my personal preferences.

Chet Guilford

By jwright650 (*****)

Date 12-15-2003 18:59

Chet, see post above.
John Wright

By bmaas1

Date 12-15-2003 21:34

Looks like a grey area. I would hate to be the welder that had to dig out all the slag if it were a production joint. I don't have a copy of the standard terms and definitions but I am sure that root and cap(cover)pass are defined differently and used for different purposes.
Just my thoughts.

Brian Maas

By jwright650 (*****)

Date 12-15-2003 21:50

Brian,
Good thought, I'll look it up in AWS A3.0. I'll post back the definitions.
John Wright

By jwright650 (*****)

Date 12-15-2003 22:20

Per AWS A3.0
Root Bead = A weld bead that extends into or includes part or all of the joint root.
Weld Face = The exposed surface of a weld on the side from which welding was done.

So, what do you think? Can we call welding the joint in one pass "legal per code?
John Wright

By thirdeye (***)

Date 12-15-2003 22:50

John

So what you are saying is that by defination the "root bead" is the "weld pass", if you can fill the joint with only one layer. That one pass would include the "root reinforcement" and "face reinforcement". A three pass weld would have a "root bead", an "intermediate weld pass" and a "cover pass". I guess you're right.

By bmaas1

Date 12-16-2003 17:13

I guess your probably right John. But I doubt you'll ever see a procedure calling this out. If I saw moments being done this way I would worry.

Brian Maas

By jwright650 (*****)

Date 12-16-2003 18:03

Hi Brian, Third Eye,
I'm not just trying to be "(w)right", I was hoping for some more opinions on this. I appreciate ya'lls comments, but was hoping for a slew of them on both sides of this issue.
I would'nt want to see someone doing this either, but what if you did? Would you try to argue that it is against the code, or say it's "OK" by the code? I'm just "what if 'ing" here, just in case one of us run up on this very thing, what would be our call? Do ya see what I'm getting at?
John Wright

By bmaas1

Date 12-16-2003 18:45

Just curious. But I wonder if AISC addresses a situation like this. Possible standard practices. Other than that John we might have to live with it or better yet let the engineer make the call if he would accept it.
I have some other ideas I'm looking in to.

Brian Maas

By bmaas1

Date 12-16-2003 19:31

Another point to consider would that much welding produce to high an interpass temperature for the material.

Just curious.

Brian Maas

By jwright650 (*****)

Date 12-16-2003 19:49

True, but what is the "max interpass temp" on a prequalified on A36 mild steel? I can find the "Minimums" listed in Table 3.2 and in the Paragraphs in 3.5.

Good job, Keep thinking. Keep the comments coming. I'm sure we are over looking something, that's why I was hoping for more involvement from the forum.
John Wright

By jwright650 (*****)

Date 12-16-2003 19:52

Brian,
I was also looking at the "max current" in Table 3.7, but it says we just have to remain within the filler metal mfg's recommended ranges.
John Wright

By bmaas1

Date 12-17-2003 03:24

John, I might have an have a solution. since groove welds are measured by depth or throat and given the plate is 3/8" thick and the max bead size is 3/8". If you measured the actual weld size by macro etch then it will be to big. If that is not possible, unless the welder can walk on water and make an absolutly flush weld then the resulting reenforcement will make the weld too large. Any underfill is not acceptable.
I may be stretching here.

Brian Maas

By jwright650 (*****)

Date 12-17-2003 12:03

Brian,
I haven't ever tried to fill a 3/8 plate in one pass, so I may set up some coupons and try it for myself. I don't call myself a good welder, so I'm not sure I can handle all that heat and keep up with the puddle. As Neikie said it might be hard to get good penetration in the root and groove faces all at the same time along with a good level cap. In the 3G position you are allowed 1/2" max root pass according to Table 3.7, so maybe any slight reinforcement won't matter. I don't know that I can do this in the vertical or not. Like I said, I don't call myself a good welder.
If you look back at Table 3.7, they list a "max single pass layer width", I guess that would be for multipass welds?, rather than trying to fit it to our particular situation.
John Wright

By bmaas1

Date 12-17-2003 15:27

The max layer width would apply if you were welding a wide v-groove.
For example making multiple weaves for a cover pass. Is this weld being made in th 1G or 3G position? The largest wire you can use is 7/64".

Brian Maas