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Up Topic Welding Industry / Inspection & Qualification / Visual acceptance length of discontinuity?
- - By Hellbent Date 09-02-2015 21:17
Hello everyone, I'm new here so take it easy on me.

I'm a CWI/E that has just started with a manufacturing company. I've had my CWI less than 2 years but never really had to use it in my previous job. There are two other CWI's at my place that I'd ask this question to, but they basically hate my guts since I'm the "young punk that asks too many questions." I will admit that I have a nasty habit of asking "why do we do it that way" or "Have we tried any other ways to do that better?"

We are run under D1.1 and only use visual inspection with the exception of lab testing.

I have found that there are many things in the code that are subject to interpretation; so I figured this was the best place to get professional interpretation so here goes.

Under visual inspection where can you find acceptable lengths of discontinuities? Table 6.1 provides some lengths but doesn't seem to answer many of my questions.

Does Figure 6.1, 6.2, 6.3 ONLY apply to welds subject to RT?

The specific question I have relates to undercut. We have a series of 2" intermittent fillet welds. We are seeing undercut running the length of one of the beads, (2 total a side) but nothing greater than 1/32." It would be a cyclically loaded nontubular connections. It would be a 1/4" bead on 1/4" plate. The other CWI's say that no more than 1/32" undercut 1/32" in length...

I hope I provided enough info... Thanks
Parent - By thirdeye (***) Date 09-02-2015 23:12 Edited 09-02-2015 23:16
For cyclically loaded non tubular connections, undercut greater than 1/32 is unacceptable unless the weld in question is transverse to stress under design loading conditions (in which case this is determined by an engineer and should be called out on the drawings... which is another issue all in itself) and then the maximum depth allowed is 0.01".

Personally... undercut and monitoring of proper heat (preheat, interpass temps, and post heat control) are two of my pet peeves, and I'm probably too strict on undercut.  I do have a go-no-go gage as well as a V-WAC gage just to prove I'm not using a fingernail and eyeball, but in the long run I shoot for no undercut and I rarely get any arguments.

I realize this is above and beyond the Code, and I am not an engineer... but in your case (with the 1/4" plate) a 1/32" of undercut is 1/8th of the plate thickness, and undercut presents a "notch" situation as well. A smooth transition is better than the stress risers associated with a sharp notch, and I have one customer that uses the term "wash" as an undercut-like condition  but without sharp edges and makes an allowance for that in their inspection procedures.  Thankfully they work mostly with thick steel, and after 35 years of having me around... they know what to expect when it comes to undercut.
Parent - - By welderbrent (*****) Date 09-03-2015 00:27 Edited 09-03-2015 01:34


Easy is our middle name... :eek:  well, okay, maybe we do bite once in a while. 

There is no such thing as a stupid question nor of asking too many questions, especially when one is new to a company and trying to learn their application of the codes.  No, there are not MANY things subject to interpretation.  BUT, there may be things open to application, especially if you have an engineer who does the altering of the applicable code per Clause 1.4.1. Your in house inspections can call items above and beyond OR behind and below the code.  It all depends upon exact application and the contract documents as to if it will be accepted by the customer and the TPI representing the customer/EOR. 

People who resent the new guy usually are insecure in their own abilities, knowledge, skills, and future.  Don't worry about it, but, watch your back.

The figures only apply when you are sent to them from a Table or the Text of the Code.  You can't just go to the ones mentioned and use that criteria as suits you. 

So, lengths of discontinuities.  Undercut in particular.  Can be a little tricky but isn't really that misleading or hard to understand.  There will be room for some variation for a manufacturer compared to a fabricator of structural steel for a high rise.  It will depend upon the product and it's usage and why D1.1 has been chosen as the applicable code.  Many things are cyclic but that doesn't mean they fall into the arena of public safety.  Also, as noted from Clause 2, you must consider number of cycles, time, and stress limits. 

So, back to lengths of undercut.  1st, doesn't matter what others say, what does the code say and what do the contract documents say? Either yours as the manufacturer or the customer's when they spec out a product for purchase? 

Going by the code, Lets work backwards: Material UNDER 1", Nothing over 1/16" undercut is allowed for over 2" of length in any 12".  Now, you didn't tell us the whole story or pitch on your intermittent fillet welds.  2" in how many inches?  2-6, 2-12?  If it is 2-6 then you will have more than 2" of undercut, according to your description, in every 12" of weld.  If it is 2-12 it might be arguable. 

Thus far, the length would be 2" of undercut is allowable in every 12" of weld if it is less than or equal to 1/16" deep.  '0' length is acceptable if it is over 1/16" in depth.

Now, you say yours is not greater than 1/32".  Code says that can be the entire length of the weld.  Even for primary members.  It can be less than or equal to 1/32" the entire length of the weld in material less than 1" in thickness.  Which applies to your situation. 

So, as long as you keep it below 1/32" you are allowable in all circumstances, lengths, and loads.  UNLESS it is transverse to tensile stress in a primary member.

Having said that, if the company policy is to not allow that much undercut, far be it from a TPI to say, 'OH, don't make our product so good.'  If the in house inspectors call out stricter controls than the code mandates that's their option.  Spend all the time, money, and resources you want to make my product ultra spectacular.

You may need to reference the company QC Manual and see what it says.  Especially if they have some form of Prequalified Fabrication Shop status.  Many companies will call out things that seem good on paper but are really costing them money that need not be spent. 

Better stop for now. 

He Is In Control, Have a Great Day,  Brent
Parent - - By louis2 (**) Date 10-24-2015 01:43 Edited 10-24-2015 01:55
Would a weld only 7" long with undercut 1/16" deep and 2" long still pass? Or would a percentage of undercut to length of weld be applied? For example, would a 1/16" depth of undercut 1" in length, along a 6" long weld pass?
Parent - - By welderbrent (*****) Date 10-24-2015 02:46
Sometimes that's the problem with codes and lines in the sand, they are always being challenged, questioned, pushed to the limit, or just plain ignored (or blown in the wind). 

Personally, if the fabricator tries to push the 'legalistic' boundaries and starts working percentages which are not found in the code, my V-Wac gauge is going into overdrive to find the smallest point that may be over 1/16" deep. 

Work with me and be reasonable and things go much smoother. 

So, part of your question will depend upon the thickness and application of the material because it says "For material equal to or greater than 1 in thick, undercut shall not exceed 1/16 in for any length of weld. (emphasis mine) Again though it is for undercut OVER 1/16" deep.  For material less than 1" it is only allowed to be 1/32" unless it is under 2" in length in any 12".  So, I don't have to start at the end of a weld and mark every foot and then measure the undercut.  I can pick my 12" any where I want.  So, with a 36" long weld I mark a 12" distance from inches 15-27 because that is where the undercut appears the worst.  And if it is an accumulated length of over 2" in that 12" and over 1/16" deep then it gets repaired.  It doesn't have to be 2" uninterrupted. 

Most companies I have worked with are very good about repairs to undercut over 1/32".  Seldom do they argue about it because they have been told by so many CA TPI's that 'if I can catch my fingernail on it you have to repair it.'  Good luck with that one in a court of law.  When was your fingernail last calibrated?  Dismissed! 

I'd have to look and see if there is already a Technical Interpretation dealing with that, but it sounds like it should be dealt with if you really want something to hang your hat on.

He Is In Control, Have a Great Day,  Brent
Parent - By louis2 (**) Date 10-24-2015 06:04
Just to clarify for me, what we're talking about here is in section six and is concerned with production welds, is that correct? What about qualifying welders as in section four? There I find simply "Undercut shall not exceed 1/32 in." What is the length here, along the full length of the weld?

My interest here comes from being a simple welding instructor trying to qualify welding students. I want to follow and apply the code correctly and I don't want to make it overly difficult on the students to achieve their goals. We are using 3/8" thick material, backing strips, 3G and 4G positions, for the S.E.N.S.E. program and other state educational/vocational type qualifications.

On a separate note, does the code say anything about using metal in the qualifying of welders where the coupons would be bent in a direction across the steel's "grain"? I was taught to bend with the length of your original piece of steel, just as a precaution. So, we use 3/8" x 8" flat plate. We cut it to length and bevel along the cut edges, weld it back together and then bend the cut out coupons in the original piece's direction of length.
- - By 803056 (*****) Date 09-03-2015 01:09
The contractor's in-house QC inspector is free to limit the allowable undercut, porosity, the amount a fillet can be undersized, etc. to what every he feels is appropriate as long as the code imposed limits are not exceeded. Of course such stringent acceptance criteria can make it nearly impossible to turn a profit. A company that isn't making a profit has a very limited life expectancy. The inspector involved, his employment will be even shorter if the management has anything between their ears and they catch on to the inspector's shenanigans.

The inspector's job is to ensure the acceptance criteria established by engineering/management and the code are met. Generally it is not the inspectors responsibility to establish what the acceptance criteria  should be.

While D1.1 may not be perfect, it is easier to comprehend and apply that some of the other welding standards I've been involved with. If there is a question regarding the code, it is the Owner's Engineer that makes the call, says "yes" or "no". It is rare that a project has the time or budget to wait for the code committee to make an official interpretation.

Best regards - Al
Parent - By Joey (***) Date 09-03-2015 15:55 Edited 09-03-2015 15:59
If you're asking for status or work progress then I see no problem. But if you ask for direction then I think you have to buy them beer first...because of asking for help or favor:yell:
Up Topic Welding Industry / Inspection & Qualification / Visual acceptance length of discontinuity?

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