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Up Topic American Welding Society Services / Technical Standards & Publications / Table 6.1 Undercut
- - By SCOTTN (***) Date 10-07-2013 13:10
The table states: For material less than 1" thick, undercut shall not exceed 1/32"with the following exception: undercut shall not exceed 1/16" for any accumulated length up to 2" in any 12" of weld.

With regard to material less than 1" thick, my interpretation of this requirement:

If a weld has only one single spot that has undercut, that one single spot cannot exceed 1/32" deep. 

If any weld has multiple spots that have undercut, these multiple spots, when the undercut lengths are added together, cannot exceed a total sum of 2" of accumulated undercut lengths in any 12" of weld, nor can any single spot of this undercut exceed 1/16" deep.  When there is an accumulation of undercut, this accumulation can exceed 1/32", but can't exceed 1/16 at any spot.

I'm on a new job and after discussions on the shop floor, I'm questioning my own interpretation.  Is my understanding correct? If not, can someone please easily explain this?
Parent - - By jwright650 (*****) Date 10-07-2013 13:22
Baiscally, if you can hang your fingernail on it, it needs to be repaired. A flashlight shown across the base material will highlight undercut so that it's easy to detect, then you can whip out the V-Wac gage on it and determine how deep it is.
Parent - - By SCOTTN (***) Date 10-07-2013 14:10
Hi John.  It's been a while.  I'm back on the forum (used to be swnorris) after a new job in Atlanta.  I'm very particular about undercut, but here, I'm told if it meets code, it's ok.  The undercut is noticeable without a flashlight, and I can hang my (uncalibrated) fingernail on it.  I've been told by the shop supervisor that 1/16" meets code, but I disagree.  There's also undercut for cyclic and tubular to consider.  I just need to be able to explain this to the guys. Is my understanding correct? If so, I will just read it to the guys just as I have posted it.
Parent - - By jwright650 (*****) Date 10-07-2013 14:46
I was wondering where you've been. Your old sign-on probably has a few PM's that are out there in cyberspace waiting for you. :wink:

I think you have the correct understanding, as written in your post above.
Do you have a way to measure it(V-Wac)? IMHO, if you can see undercut without a flashlight, it will mostlikey measure deep enough to need repairing.
Parent - By SCOTTN (***) Date 10-07-2013 14:51
I have the bridgecam to check the depth.  Thanks John.
Parent - - By ctacker (****) Date 10-08-2013 04:40 Edited 10-08-2013 04:50
I think your interpretation is a little off, Basically (my interpretation) you can have undercut up to 1/16" for up to 2" of weld in any 12" of weld. If a weld has one single spot of undercut,   up to 1/16" is allowed. you can have 32 spots of (up to) 1/16" undercut that is 1/16" long in 12" of weld, or a 2" long undercut that is up to 1/16" deep in 12" of weld.

There were many times when I was QA manager where the third party came in and hooked his fingernail and tried to reject undercut without using a v-wac gauge. My reply after I verified with my own V-wac gauge was that we would repair it, document and photograph before and after pictures and send his company the bill. (I always won that argument, even though I don't like undercut myself, but I was paid to help the company put out a product that met the specifications, and not waste money going overboard.) I have learned as a third party inspector that you can't reject something if it is not out of tolerance, or you may be picking a battle you can't win (and don't want to fight).
Hope my explanation was ok. (it was somewhat easy :lol: )

Edit: BTW, welcome back Scott. wondered where you disappeared to. Sounds like your in a fabrication plant where you will be battling production trying to get a quality product. I did that, and done just fine by learning to let the minimum requirements go and even going to battle for the company when we were rejected by third party inspectors that did not have the proper gauges to do their job. (I always did, and always won those battles, that's why I was offered another 6K a year to stay. but I hated it actually and left anyway). Its a fine line you have to walk to keep everyone happy and get a quality product.
Parent - - By Superflux (****) Date 10-08-2013 06:28 Edited 10-08-2013 07:05
My interpretation for U/C per Table 6.1 is closer to ctacker's than Scott's. It IS a confusing piece of literature that has at least one more possible interpretive twist to it.
Now my "calibrated" fingernail (middle one left hand, so I can show the shop QC) and flashlight can detect <1/64th" U/C. 2mm(?), This is the 3rd 1/16" to metric conversion in codes/specs I've run into, others are 1.5mm and 1.6mm (Which is my personal favorite since it is so easy to correlate with 1/16... 1.6 - 1/16 is just easy to remember). When I work as TPI/Client Rep, I am very careful to reject anything that is more than a few seconds of "cosmetic touch up". Rule #1! "NEVER quote the code unless reading it from the book!". Many TPI contracts require that I use ONLY the shop's gauges and tools. Cambridge Gauges and V-Wacs can be adjusted to re-zero and it is amazing how many times I have seen them out of whack. I love it when you see welders use the point of a Cambridge gauge to pick slag with... grrrrrr!

Welcome back Scott.
I was just thinking about you a while back and hoped you would return. Any words of wisdom you could share from your cornflakes these days?

edit. BridgeCam, sorry I'm old and still call them Cambridge gages from the old days when they were made in and by Cambridge Tools before selling the mfg. rights to GAL Gage Co.
Parent - - By SCOTTN (***) Date 10-08-2013 11:30
Great to be back.  As for words of wisdom, my cornflakes have instructed me to keep my thoughts to myself.  Against my better judgement, I will have to do that, because my cornflakes will kill me if I disobey them.
Parent - By Lawrence (*****) Date 10-08-2013 12:15
Welcome back Scott.

My low carb breakfast welcomes you back also.   It has no problem speaking up... Usually about 8:30 am   :)
Parent - - By ctacker (****) Date 10-08-2013 15:55
Have we worked together before?  I have seen that calibrated fingernail saluting me on more than one occasion.
Parent - By Superflux (****) Date 10-08-2013 17:16 Edited 10-08-2013 17:19
"Have we worked together before?"
Hmmm. Maybe? I do stray out of the neighborhood on occasion.
I'm still not sure about the 32 places of U/C you mentioned in an earlier post. But I can only count to 21 with my available birth given digits.
Parent - - By jwright650 (*****) Date 10-08-2013 12:50
I'm sticking with Scott on this, The 1/16" that you guys are saying is acceptable, is the length not the depth.
1/32" is the max depth for material less than 1" thick. (one spot or dozens of spots) more than 2" of total accumulated length of undercut 1/32" deep that is 1/16" or longer in length for any 12" of weld.
Parent - - By Superflux (****) Date 10-08-2013 13:56
Copied from D1.1 2004:
"(A) For material less than 1 in. [25 mm] thick, undercut shall not exceed 1/32 in. [1 mm], with the following exception: undercut shall not exceed 1/16 in. [2 mm] for any accumulated length up to 2 in. [50 mm] in any 12 in. [300 mm]. For material equal to or greater than 1 in. thick, undercut shall not exceed 1/16 in. [2 mm] for any length of weld"
jwright650 Sir, as I reread this over and over, it seems to (ME to) indicate that 1/16" maximum is acceptable for OVER 1" thick material, Correct?
BUT that 1/32" to 1/16" (maximum!) is ok as long as it's total length (multiple places) does not exceed 2" in any 12 inches.
Put differently, A little bit of no more than 1/16" is ok here and there as long as it aint TOO MUCH...
Not wanting to be argumentative, only desperately trying to get it all sorted out in my very abused brain.
I wish that the author of paragraph 7 would not have been so brief and added some words like depth to clarify this for us "challenged" readers.
I'm sticking with 1/16" depth right now and think the weld could have a single length of 1/16" U/C up to 2" long in a 12" weld.
I've been wrong before.
Parent - By jwright650 (*****) Date 10-08-2013 14:15
I'm in agreement with materials 1" and over. (1/16" max for the 1" and over materials.)
But Scott asked about materials less than 1" to which I read 1/32" max. except with the following exception regarding the accummulated length up to 2" in 12"[paraphrased]

Hmmm.....Maybe I'm reading too much into what is being said for Item(7) on Table 6.1.
That "exception" is bothering me now that you guys have challenged my interpretation.....maybe I've been too hard on undercut for the past 15 years.
Parent - - By ctacker (****) Date 10-08-2013 14:11
This is straight out of the steel structures technology center handbook, for steel less than 1 inch thick, undercut up to and including one 32nd inch is permitted. A maximum 1/16 inch undercut is permitted for an accumulated length of 2 inches in any 12 inches of Weld length.
Parent - - By SCOTTN (***) Date 10-08-2013 15:05
So, to understand, for materials 1" or less, 1/32 deep or less is acceptable, period, regardless of whether it exists for the entire length of the weld or not.  And, a maximum undercut of no more than 1/16 deep is acceptable as long as, when it's length(s) are added together, do not add up to more than 2" in any 12" of weld length.  Is my understanding correct? If so, like John, maybe I've been too hard on undercut in the past.  I just don't like to see it, but I'm good with it as long as it meets code.
Parent - - By ctacker (****) Date 10-08-2013 15:08
That is correct. Sorry for the short post it's hard to type my phone while in the middle of a job.
Parent - - By jwright650 (*****) Date 10-08-2013 15:26
Thanks guys for straightening me my shop, I can be tougher on the undercut and have the guys repair as I please, but I sure wouldn't want to make waves out on someone else's jobsite when I didn't need to.
Parent - By Superflux (****) Date 10-08-2013 17:13

Yes, there is much joy to be had bludgeoning the welders and foremen (and other QC!) into submission when in your own shop, but when doing the TPI thing, I am very quick at the draw to say "I'll get back with you on this (or that)."
Undercut and "ropiness" are 2 of my pet peeves. I find U/C to be well defined, but overlap and excess convexity can be tough to make a full fledged call without additional NDE (and sometimes if the point really needs to be made, DESTRUCTIVE) other than Visual.
Parent - By welderbrent (*****) Date 10-08-2013 17:59
John and Scott (alias ScottN, or swnorris: welcome BACK to the AWS Welding Forum),

I would have to side with ctacker and Super on this.  And I must say I love it when the inhouse guys are so picky about undercut that they mark every little thing. 

Then there are those who think the cyclic dimensions apply because the materials are going into a seismic zone.  But, unless it is called out to be part of the seismic framing it isn't seismic code applicable.  And there is a difference between seismic, dynamic, and cyclic.  Sometimes they go together, sometimes they don't.  Bottom line, TPI's and in house apply the cyclic rules for undercut when it doesn't apply.  Let the in house guys do it.  But be very careful as the TPI if you want to enforce cyclic undercut specs on a job.

But, 1/32 for the continuous run or up to 1/16 for short spots not to exceed 2" out of 12".

Have a Great Day,  Brent
- - By SCOTTN (***) Date 10-08-2013 15:20
Oops. I meant to say "for materials less than 1" thick...
Parent - - By rjtinsp (*) Date 10-08-2013 17:43
For statically loaded nontubular connections the following would apply:

For materials less than 1 inch thick undercut 1/32 inch deep is allowed regardless of length, and under cut 1/16 inch is acceptable with an accumulated length up to 2 inches.

For materials 1inch thick and greater undercut 1/16 inch deep is allowed regardless of length.
Parent - - By SCOTTN (***) Date 10-08-2013 17:50
What about undercut for cyclic loaded non tubular, and tubular?
Parent - - By jwright650 (*****) Date 10-08-2013 17:52
See Table 6.1(7)(B)....for tubular and cyclically loaded
Parent - By Superflux (****) Date 10-08-2013 20:41
Whoahhh. Time out.
See item "B"!
One issue at a time.
We are deviating beyond the Original Posting.
Oooohhhh! Cyclics. Bad to the bone stuff. FUN.
Let the Games Begin!
Up Topic American Welding Society Services / Technical Standards & Publications / Table 6.1 Undercut

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