Undercut

Date 09-11-2008 22:47

I would tend to think that the allowable would be prorated for welds measuring less than 12 inches in length.

Best regards - Al

By Travis Collins (**)

Date 09-12-2008 13:11

So allowing 2" in 12" is roughly 16.6% of the weld length. And you like me believe this sould be this percentage could be applied to shorter weld lengths?

By swnorris (****)

Date 09-12-2008 13:23

So, according to your fellow CWI, undercut greater than 1/32" is permissible for welds under 12" in length? I disagree with that. The key word is "accumulated", which means growth by continuous additions.
During the qualification of tack welders, if one criteria for visual acceptance of tack welds is no undercut exceeding 1/32", why would undercut greater than 1/32" be permissible for final welds under 12" in length?

By Travis Collins (**)

Date 09-12-2008 16:02

No he say the 1/16" exception to the rule ONLY appies to welds 12" in lengh or longer.

By 803056

Date 09-13-2008 03:06

Qualification has separate acceptance criteria that differs from the acceptance criteria applied to production welds.

Best regards - Al

By bmaas1

Date 09-12-2008 14:42

Travis,

I would agree with you on this. I have always used that ratio welds under 12 inches in length. So if a weld is 3 inches long the allowable would be 1/2 inch. Maybe I am wrong.

Brian

By michael kniolek (***)

Date 09-12-2008 21:49

I can see why he thinks that the weld needs to be 12" or larger, BUT aws does not know when a weld is 6" 11" 12" so....
A weld that has just under 1/32 undercut along the whole length is ok....agreed?
Now....Another weld that is 11" has only 1 3/4 of accumulated undercut that is just under 1/16 deep this is ok too......Yes?
A third 11" weld has undercut @ 1/16" for 2 1/4" this weld has exceeded the limmit for accumulated length of undercut and is rejectable.
i guess he could be right if the last part of the statment was in any full 12" of weld.
Do you all agree or do i have this confused?
as for 6" of weld i do not see where a ratio should be made and id say that if you had a 6" weld that had just under 1/16 undercut for a length of 1 3/4 inch id say that the 12" has not been exceeded and would accept the weld.<------not sure about this but where does it say or a ratio of the 12"
MDK

By ctacker (****)

Date 09-12-2008 22:15

I would agree with all but the last question. It could be argued either way though. might be a good one to ask the code writers.
A 1/16" of undercut is quite a lot, My company has a 1/32" for 2inch accumulated on 12" and 1/64" (half of whats allowed in D1.1)on all weldments and we do alot of heavy plate and castings(up to 8").

very seldom even at that I reject a weld for undercut. it usually happens to the new guys, but they learn quick how to control it.

there is something wrong if your getting 1/16" inch undercut and it also reflects on the quality of your product. Personally I'd be embarrased if I left that much undercut!

By michael kniolek (***)

Date 09-12-2008 22:29

true, I do not allow any undercut as you, its can be controlled and is an indication of poor workmanship.
As for my last statment i too feel that it is alot of undercut to allow but i didnot see any further restrctions governing welds under 12" thats why i mentioned that the last part of the statment may have been writen as 12" of full weld.
For such a simple thing its not very clear i read it abot 20 times.
thats why if it doesnt cost a fortune go beyond what is called for and youll have no worries.
MDK

By 803056

Date 09-13-2008 03:09

As a third party inspector, acceptance has to be per the applicable welding standard. Tighter controls can be applied by the fabricator provided they are not less stringent than what is permitted by the applicable standard.

Best regards - Al

By waynekoe (**)

Date 09-14-2008 04:07

I think an important thing to remember here is that the code says "in any 12 inches". I take this to mean that you have two weld toes, so, any 6" weld would have 12 inches that are subject to the two inches in any 12. And then there's the type of weldment or location of the weld in question in a particular weldment. A base plate or column cap to a gravity column is a static load and can absorb the effects of more undercut, whereas a gusset to baseplate in a brace connection would be a primary connection and limited to .01" for transverse welds and 1/32" for all others. Al's corect in saying that what you do in the confines of your shop is up to you, you can be as strict as you desire, but in the field the inspector is bound by the standards set down by code, not what you think it should look like.

By michael kniolek (***)

Date 09-14-2008 13:43

Are you saying that each toe of a weld should be added together? In a six inch weld the top six" and the bottom 6" are added to equal 12"?
so in a 12" weld 24" is the measurment used for evaluation of this weld,12 for the top 12 for the bottom?

if I have a 12 " weld in the first 6" on the upper leg @ the toe, i have undercut just under 1\16 for a length of 1.75 in that same six inches i have no undercut on the bottom toe.......are you saying that this satisfies the 12" requirment?
then in the next six inches on the bottom toe i have undercut just under 1\16 for a length of 1" and no other undercut in that portion, this would be acceptable?
or If i understand your interpitaion ( any i may not ) in a 12 " weld on the upper toe i have undercut just under 1\16 for a length of 1.75 and no other undercut. (does this satisfy the 12")
then on the bottom toe i have undercut just under 1\16 for a length of 1.5 "and no other undercut. what is the disposion?

Because if i were inspecting this 12" weld i would treat both toes as part of the same weld, so in the first 6" on the upper leg @ the toe i have undercut just under 1\16 for a length of 1.75 in that same six inches i have no undercut on the bottom toe,then in the next six inches on the bottom toe i have undercut just under 1\16 for a length of 1" and no other undercut in that portion, i would not accept this.

I may be over analizing this and i know i dont fully understand what it is you mean by (any 6" weld would have 12 inches that are subject to the two inches in any 12)
Could any1 chime in on this maybe a few examples...........
Are the toes to be added together or inspected independently or are both toes considered part of the same weld.
12" is 12" and i always considered both toes as part of a weld together.
MDK

By jrw159

Date 09-14-2008 18:26

waynekoe,
Very interesting outlook on this subject. I had never thought of it in that sense. I am interested in others opinions about this. :-)

jrw159

By ctacker (****)

Date 09-14-2008 19:09 Edited 09-14-2008 19:16

so your saying a 2" skip weld every 4 inches only needs to be 1" in length to cover 2" of weld toes?
I wouldn't think the code would count the 2 toes as seperate welds.
when the code calls for 12" of weld, I take it as a weld 1' long. if you have 1/16" undercut accumulated on both toes that add up to under 2" you would be in compliance!

By michael kniolek (***)

Date 09-14-2008 19:50 Edited 09-14-2008 20:56

Ctacker, i agree with your statment .....

"when the code calls for 12" of weld, I take it as a weld 1' long. if you have 1/16" undercut accumulated on both toes that add up to under 2" you would be in compliance!"

My understanding of the parts that makes up a fillet weld basicly consists of two toes, two legs, 1 throat,and 1 root.
Now what about a weld that is 6" in that weld if i had just under 1/16 undercut that added up to 1 3/4" would you consider that acceptable i would because the accumulation of 2" in the 12" length has not been exceeded what do you think?
If the toes were considered as top and bottom i feel that the spec could be minipulated in many different ways,like if the top toe was inspected for 12" and found to have the 1/16 undercut for a length of 1.75" with that thought applied the top would pass, then moving to the bottom 12" and the same condition was found it would also be dispositioned as acceptable, but if both toes were considered at the same time the weld is clearly a reject.
MDK

On another note
If a spec calls for 10% of all welds to be MT inspected how would you do this......
The job has one weld measuring 10" another weld @ 50" And a third @ 40" in 3 locations 10 at one location 50 at another and 40 @ the third.

would you mt 10" of any weld and be done with it, or you you MT 10" of each weld?

By ctacker (****)

Date 09-14-2008 20:13 Edited 09-14-2008 20:28

I would also agree, If you counted each weld toe as accumulated length,you would have 12" (accumulated) in 6" of weld length,thereby allowing 2 times what would be acceptable.
you would be allowed 4" of 1/16" undercut every 12" of weld length.

Edit:
"Now what about a weld that is 6" in that weld if i had just under 1/16 undercut that added up to 1 3/4" would you consider that acceptable i would because the accumulation of 2" in the 12" length has not been exceeded what do you think?"
I see where your thinking comes from, because if your undercut(1/16") is 1-3/4" long, and that all falls in 2" of length in a weld that is 12" long you would be acceptable.
BUT, if your weld was only 6" in length, with 1-3/4" of undercut(1/16") your weld would be half as strong as the 12" weld and the undercut would be more than allowed.
I would prorate it.

take a 6" sq. tube that was welded on the flats and not the radiused corners, you weld 4 sides (except the radius corners). you would have 4 welds under 6" long. do you actually think that 1-3/4" of undercut would be allowed on each side?
My guess is no, 2 sides would equal 12" acumulated( minus the corners that were not welded).
I would agree with Al about prorating the length!

By michael kniolek (***)

Date 09-14-2008 20:54

As for the 6" i see where your thinking comes from.
THX
MDK

By ctacker (****)

Date 09-14-2008 20:32 Edited 09-14-2008 20:36

On another note
If a spec calls for 10% of all welds to be MT inspected how would you do this......
The job has one weld measuring 10" another weld @ 50" And a third @ 40" in 3 locations.

would you mt 10" of any weld and be done with it, or you you MT 10" of each weld?

I would add up all the welds length 10 + 50 + (40X3) = 180 " take .10 X180 and you would MT 18 inches of weld!
Edit,
if it said 10% of EACH weld, then i would MT 1" of the 10" weld 5" of the 50" weld and so forth!

By michael kniolek (***)

Date 09-14-2008 20:40

Bingo
this was an issue years ago for me and the spec actualy did say each weld the shop manager wanted me to inspect some of the bearings near the end of the job and i told him i needed to MT each weld.
MDK

By waynekoe (**)

Date 09-15-2008 18:46 Edited 09-15-2008 18:50

10% is 10%. You can take from any place your little heart desires. If you take 10% of each and every weld or 10% of the total number of welds which is the most practical way to go about it I think, your still doing 10%.

As for the fillet welds, I don't feel you can, from a code point of view, lump all fillet welds together. Table 6.1 spells out 3 situations. Situation A-Statically loaded connections of non primary members of 1" and less and situation B-greater than 1" in thickness and situation C which are primary members. So, the way I see it, a fillet welded lap joint 10' long could have 1/16" deep undercut running its entire length and be in compliance with the code. Table 6.1 7A says "shall not exceed 1/16" for any accumulated 2" in any 12" which I interpret to mean 6" ea. top and bottom combined; 12" top and 12" bottom; or turn the freakin thing inside out, any 12 is any 12. Like was stated earlier by Al, when your in a shop situation, and your in charge of things like that, you can call it any way you like.

By HgTX

Date 09-23-2008 17:04

Make sure it really says 10% of all welds.

D1.5, for example, says 12" in every 10' of weld, and 12" for every weld under 10'. We simplify that to "10% MT" but that's not really what it is. (Even though every once in a while someone still asks if they can do 100% MT on one out of every ten girders.)

Hg

By CHGuilford (****)

Date 09-24-2008 17:00

HgTX,
Interesting that you brought that up. I run into that interpretaion all the time - that many folks believe you can MT a few welds at 100%, supposedly to add up to 10% of the total of all weld lengths. I don't share that thinking; many disagree, but the wording is clear to me.

All,
I too appreciate this thread. I had never really thought a lot about measuring undercut but some interesting points are brought up. In general I solve it by injecting my personal opinion. Even 1/32" undercut looks like a lot, so I have it corrected - largely because it takes far less time to do that than it does to justify my acceptance of noticeable undercut to a customer. And frankly, if we are getting so much that I have to look hard at the undercut, then something or someone needs adjusting.

One point I would really like to see resolved is the notion that each side of a weld counts for the total undercut length. I have never thought about that either because, again, it's easier to fix that it is to justify it. But that is an interesting point.

A very good thread!

By ctacker (****)

Date 10-05-2008 22:45

Wayne,
I found this in one of my specs. that is also the way I interpret D1.1 using a "layer" of weld for a weld length. don't want to stir the pot but it was a good discusion that ended without a clear answer.
That could bring another question, you have a 4 inch wide weld face, would you count each weld pass or just the toes?
ACCEPTANCE STANDARD
The following requirements apply to any one layer of weld, including root and final. "One layer" is generally intended to mean a single plane of weld stringer beads, but suitable interpretation must be used if the shape results in a curving layer.

LINEAR DISCONTINUITY: No cracks, including crater cracks, are allowed in welds or heat affected zones. No other linear discontinuity in these areas shall exceed 6mm/.25" in length.

POROSITY: Porosity shall not exceed (4) holes in every 100 mm/4.0" of length of a single weld bead. No single void shall exceed 1.5 mm/.06" in diameter.

SLAG: No visual slag in any layer is allowed.

UNDERCUTTING: Undercutting shall not exceed 1.5 mm/.06" for material over 13 mm/.50" in thickness.

By waynekoe (**)

Date 10-07-2008 04:30 Edited 10-07-2008 04:36

I guess I'm basing my theory on the description of "any 12 inches". And, if so, under that clause, wouldn't, couldn't, or shouldn't undercut be deemed a linear discontinuity limited to a maximum length of .250" regardless of depth or location or accumulated length? I guess I could be answering my own question here, but, I take it this way. If you need to have an accumulated length of two inches in any twelve, both weld toes have to be combined in order to get an accumulated length, why shouldn't the length of each weld toe be considered when acquiring those twelve inches?

This is the edited part, I keep wanting to call you either Charlie or Carl for some reason, am I screwed up on that, or are any of those actually your name?-Wayne

By ctacker (****)

Date 10-07-2008 14:04

Wayne,
I would agree with you on the both weld toes being combined to get an accumulated length, and I could agree with you on counting each toe as part of the 12".(but I won't for the time being :) ) The way I have always done it and seen it done is counting the Layer as the weld, a 12" weld has 24" of weld toes, I think we would agree on that! The part I don't agree on is counting each toe as a seperate weld. I do realize that on a 1-3/4 inch weld, you do have almost 2.5 iches of weld face, and each toe would be a different weld pass, but they are all still in the same layer, which I take to be a single weld.
I would like to hear how the experts are seeing this (Not that I don't consider you an expert yourself). I am open to change if I have been doing it wrong!
Regards, Carl (that answers your last question :) )

By waynekoe (**)

Date 10-07-2008 15:11

Carl, Please. My name and the word expert should never be used in the same paragraph. I agree with you all the way around, and the weld length probably should be considered as the sum of all its parts, but it is an interesting way to look at it. In looking back at the whole thing, a person really could get carried away in breaking down the weld length if considering both weld toes. I feel a more concise definition of "in any 12 inches" wouldn't hurt either. Each leg height of a fillet weld is measured indepently of the each other, so, If one leg is short by 1/16" and the other leg is a 1/16" longer, you can't average the two out and say, "well, I still have the required weld area". I'm not arguing any point here, pro or con. I just thought it was an interesting way to look at it at the time I wrote it. Well, I must go earn my keep for the day. Stay safe. Wayne

By ctacker (****)

Date 10-07-2008 18:50

Wayne,
I agree it is an interesting way to look at it. But it does seem like it would allow 2 times what the code intended. maybe I'm wrong. but I gotta admit, I never even looked at it the way you mentioned. and it did get me thinking about it.
As for being an expert, aren't we all in one way or another, Even if it is in BS'n :)
Have a great day!
Carl

By Travis Collins (**)

Date 09-15-2008 18:51

MDK
I havent thought of that, but would you really want to allow the 2" in any weld? I understand that you havent exceed the 2 in 12, but would it be correct to use that on a 4" weld? That is why I thought that it would go in a pecentage of the weld length. Or maybe Im incorrect because it doesnt give you a percentage of the 12" that can be undercut, just a inch amount.

By Mikeqc1 (****)

Date 09-15-2008 19:29

i agree i would not want to see that undercut in a small weld, but i dont see any reference to welds smaller than that.
MDK

By Travis Collins (**)

Date 09-15-2008 20:50

Well I guess I will let my fellow CWI check welds as he sees the code is written, and I will check them as I see it. It is confusing for the fabricators tho, because we are checking the same people and reading the code differently. And he is a person who will not admit he is wrong even if he knows he is. I can not convince him to look at it from my point of view. He thought you guys would laugh and think this was a stupid question when I posted it. Thanks for all your help