Stud Welding Acceptance Criteria

Date 08-26-2014 12:12

Thanks Guys. I’m still looking for a clear explanation/definition of "nonfusion on the legs of the flash and small shrink fissures". I have my own thoughts, but I would still like to hear from others, because my understanding (see my initial post) and what was explained to me are two very different interpretations. That’s what initiated my post. The individual who explained his interpretation also told me that as long as the stud is welded 90% at the base, it’s acceptable per D1.1. In my 37 years, I have never heard of this with regard to acceptance criteria. I would appreciate any further comments.
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By welderbrent (*****)

Date 08-26-2014 13:27

Good morning Scott,

Do you have to work on those or do they just keep coming naturally?? :lol:

Anyway, no, there is no 90%. Now, don't remember all of earlier post, look at 7.7.1.3 in the 2010 edition: "Flash Requirement. Studs shall exhibit full 360° flash with no evidence of undercut into the stud base.

Combine that with some of other references made already on repair and replace look at the commentary for 7.8. We can bend any number of studs we want to a 15° angle to verify soundness. If we don't like the looks of them, no matter how many their people have already 'rung', bent, or whatever, we can bend more.

So, bend them. If they don't come loose or at least tear, they are good to go.

Now, the flash is made up of molten metal that is pushed out from under the stud and comes from both the stud and base metal (I'm sure you know but thought I would start at the beginning and walk through the process). With the shields in place the 'spray' of the metal is controlled and contained to produce the flash around the base of the stud. That spray will often exhibit discontinuities if you will that if it were a weld would be unacceptable. Things like the appearance of lack of fusion- nonfusion on legs, porosity, small shrink fissures, etc. Most of these are acceptable as long as the flash is complete for the full 360°. It may be higher in one area and lower in another. Some may term it incomplete because of these discontinuities but did it produce flash all the way around? If so, it is good. But, if you are unsure, bend it. Don't just ring it, bend it to a 15° angle. Code says you as the Verification Inspector can do that. If you are the contractors in house, you can too. At least smack that baby good and hard and see if she burps. You would be surprised how many I have had go flying that had a 360° flash. I often grab a 4 lb and ring all of them on a member with a pretty good smack.

Bottom line, the flash doesn't have to be a perfect, defect free, ring of tightly adhered metal around the base of the stud. But it does have to be present for the full 360° circle.

All of us have slightly differing views of the gray area between a perfectly sized fillet weld and undersized, between repairable overlap and leave it alone it is acceptable, etc. There are those repair areas that are no brainers. There are welds that are beyond question for acceptance. But there are areas where one of us would accept and another reject and/or even we ourselves would call it one way one time and the opposite the next time. So also with studs. You won't get a perfect solution for some of those in that area. It is a judgement call even if we don't like to admit that we make those. 'It either meets the code or it doesn't!' YEAH RIGHT. Good luck with that one.

But there is no wiggle room for 90%. The code says a full 360° or repair or replace. The question is if the 360° flash is 'pure' enough? Usually so. I look mainly for those that go into the stud. Sometimes you can look at the base and even with a 360° flash you can see under the edge of the stud. OOPPS. Not good. Even if it stands up to my hammer blow it needs repair.

Don't know what else to say. Studs are a different animal. Horses I think. Some men think they are, studs that is.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 08-26-2014 13:39

Thanks Brent. Some did not have a full 360 degree flash (welded all around). On those, they had made the decision to hit them with a hammer in the opposite direction of the unwelded portion, which was no more than 1/8". They didn't break away from the base metal, so they made the decision to let them go. They still don't meet code, so I just noted it on my report.

By 803056

Date 08-26-2014 14:04 Edited 08-26-2014 14:07

In your opinion the stud is noncompliant. Report your observations and include a photograph to aid the Engineer in making a decision to "accept as is" or "require corrective action". Let the Engineer make the final determination. That's his job. It isn't your job to argue the point with the contractor, nor should you have to. D1.1 says the contractor is required to make any corrections required by the Verification Inspector. If they disagree, they can always back charge the Owner for unnecessary work. All the more reason to completely document any and all work deemed to be nonconforming. A ruler in the photograph makes it difficult to argue whether the item is large than or less than the value allowed by code.

Under the auspices of D1.1, the Verification Inspector has very little weight to throw around. The heavy weight belongs to the Engineer representing the Owner.

I worked on one project where my matching orders were "Do not say anything to the contractor. Everything is in your report, including conversations with the contractor (there will be very few), telephone conversations, and your findings. The Engineer will make a determination on all nonconforming work and will communicate the disposition in his written response to the contractor." It made for an interesting project, but the reasoning was sound. The contractor had a reputation of giving previous inspector a hard time. By the end of the project the contractor was pleading to know as soon as possible if there were any deficiencies. I told him he would have to take up the matter with the Owner and the Engineer.

The project was finished with the protocol that was established by the Engineer and the Owner. The contractor jumped through hoops to keep the water smooth on the next project where he and I worked together. The lesson was learned.

Best regards - Al

By SCOTTN

Date 08-26-2014 14:19

Thanks Al.

By welderbrent (*****)

Date 08-26-2014 14:43

For all I said above, I agree with Al. Way too often, some among us try to take the responsibility upon themselves to be judge, jury, and executioner. Not so. But that doesn't mean I have to accept anything that doesn't meet the code requirements. Just make it known to the contractor and if they don't repair it I put it in a Non-Compliant report. These steps are mandatory on my current project which has LA codes to comply to.

Always know your job specs as well as your applicable codes in order to follow the proper procedures. (I know you know most of this, just covering my bases with other readers so they don't think I am one of the god complex inspectors)

There is more structure and order to our job than many realize but the main marching orders come from our client. So then one must also distinguish their responsibilities between QC and QA. There is more than a little difference.

Anyway, thought I'd better clarify my position as to job descriptions.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 08-26-2014 15:28

Thanks Brent. I simply cite what I feel are solid code references. I always listen to the interpretations of others, which are often far fetched attempts to justify letting something go that clearly does not meet code. They try to read something into it that's just not there, and some are just as serious in their interpretations as I am in mine. I just report what I see, and if the higher ups make the decision to let something go, I state it as such in my report. As you mentioned, some inspectors do have a God complex, but like you, I'm not one of them. Sometimes I don't like what I see, but as long as it meets code criteria and job specs., I won't reject it. I always try to help the fabricator and work with them as much as possible. I stand firm on my understandings and interpretations, though I'm always open to hear other interpretations. I think about what's being said, and if it makes sense to me and causes me to question my own interpretation, then I reconsider my stance.

By 46.00

Date 08-30-2014 04:49

From your description, these studs are non compliant with your working standard! I would document it and pass on to the Engineer if I was overruled! We all eventually get into this situation, as Inspectors, most times it's an interpretation issue, sometime times it's a 'I know better than you' issue! Never feel the need to revert to 'When I was a Welder........!'

By weldingpolice Date 09-12-2014 13:21 Edited 11-01-2014 15:38

By 803056

Date 09-12-2014 16:56

Where in AWS D1.1 is the "ringing" test described or criteria provided for what passes or what fails?

Just asking.

Al

By weldingpolice Date 09-12-2014 18:16 Edited 11-01-2014 15:38

By 803056

Date 09-12-2014 18:43

Not specifically but I am referring to the good folks that developed the LA specifications; Forest Gump had it right, "Stupid is as stupid does."

I imagine a good number of acceptable studs would fly off when smacked with a 6 pound sledge hammer.

Al

By welderbrent (*****)

Date 09-12-2014 23:26

You are correct about the LA requirements but Al's point, TO ME, is that the code would take into account that a percentage will not be good for strength but that has been engineered in and for VT requirements ringing studs is actually beyond the average inspectors responsibility and/or need. We are visual inspectors and AWS committees tasked with establishing a minimum standard did so full well knowing that VT cannot catch everything. Are you going to RT, UT, and MT all of those studs as well just to make sure that you didn't miss one when you rang them? Just a rhetorical question to show my point and how overboard people can go when left to emotions and money motives for making decisions.

Having said that, so others can see how varied our jobs are and not everything is cut and dried with only D1.1 as our standard, for jobs going into LA we ring studs as well. Current project specifies use of a 6 lb hammer.... now you did it, I have to look it up but I'm pretty sure it is a 6 lb haven't done one in a while. And yes, it would surprise many how often a perfectly good looking stud with 360° flash will go flying without a super heavy swing. LA has obvious if not sound reasons for going beyond D1.1 and D1.8 even if they seem hard to scientifically justify to many of us. But earthquakes will give the best of engineering a real test and especially on buildings over 50 floors high, current project is 76 floors in downtown LA.

To become LA Deputy Inspector certified you must know LA building code which is modified CA building code which is modified IBC. Includes all addendums that they deemed proprietary for safety of the public in their jurisdiction. Then, you must have a copy of and be familiar with additional requirements as spelled out in the LADBS Bulletins. 100's of them dealing with information beyond even the LABC.

As the original question was not aimed at LA this has been a slight hijack of the actual practices that need to be considered when meeting the requirements of D1.1 for stud inspections. But I hope it is enlightening to others as to making sure they know everything about the job they are inspecting. Look at your contract documents every time you are tasked with project verification regardless of your employer; contractor or engineer.

He Is In Control, Have a Great Day, Brent

By welderbrent (*****)

Date 09-12-2014 23:27

Sorry Al, should have put that other one under his post, hit the wrong 'reply' button.

BB

By weldingpolice Date 09-13-2014 03:43 Edited 11-01-2014 15:38

By welderbrent (*****)

Date 09-13-2014 05:48

As previously brought up, the inspector can choose to bend test a reasonable number of additional studs per D1.1. To me, that means I can go down and ring any amount of studs I want. If I have nothing better to do and am not holding up the job by ringing studs on a column or beam then go ahead, knock oneself out (with a bad bounce off a bad stud...LOL). Since I am not bending them but satisfying my own morbid curiosity, why not?

I believe most of us with any amount of stud shooting and inspecting experience can spot indicators that there may be a problem even with a good flash; excessive uncleaned rust on the WF down through the area where the studs were shot, quality of flash ring, and many other items that make the red flags tell us to ring a few for safety sake.

Example, on this job, I was watching as they started in house inspection of studs. The rust seemed a little heavy. Sure enough, studs with good flash started coming off and leaving about an 1/8" deep hole everywhere they had been. We had told them to clean better before shooting studs. Not that it has to be cleaned to shiny metal, but you can't leave heavy rust on the surface and expect to get a good bond when shooting through it. We made sure they used the six pounder with a little extra effort on every stud on two different columns that were not prepared as they should have been. They also had many extra repairs because of lack of good flash on those two. Haven't had much problem with them doing the prep since then.

Many shops here in AZ hate to see me coming when they are shooting studs. Even without the mandatory ring I often grab my 4 pounder and ring a good many if not all studs. Just a good bounce off the side of each one on the first couple of beams or columns. It will quickly show if proper procedures have been used in the attachment process. After that I check those that I think look suspicious.

I understand Al's query about where the specification calls for such in order to justify the test, but as a good portion of my work is headed for LA, San Diego, Las Vegas, and other earthquake code required areas, if I have the ability to bend them, I most certainly can ring as many of them as I see fit. And while the shops don't always like it, they have never complained and neither have my customers.

One more thing, I thought this was already posted, one must take all the different sub-clauses into account when considering bends on studs without 360° flash. The fabricator/contractor has the choice to remove and replace, or, repair the stud. Either way, the inspector, in house or verification, is to bend the stud either before or after the repair/replace and make sure of it's soundness. This, my interpretation of this portion, is based also upon the commentary, C5.4 Standard Practices for Stud Welding (or some such title), and what I believe to be proper critical interpretation, comprehension, and application of Clause 7.5 and 7.7.

Just my two tin pennies worth.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 09-13-2014 12:05

Sounds like more problems with studs in the field than in my experience in the shop. I have just a couple of thoughts on that. Although improper setup accounts for probably 90% of weld failures, If specific thru-deck ferrules are not being used in the field, that could be part of the problem. Thru-deck ferrules typically have a thicker wall than standard ferrules, and if I remember correctly, they have a different venting pattern at the base of the ferrule so that when the arc is initiated, the flux in the end of the stud end is consumed and deoxidizes the weld area by expelling gases through the vents, which prevents oxygen from entering the weld area, so it’s important to make sure the stud supplier is furnishing the correct type of ferrules for the application. Also, ferrules must be kept dry. If they absorb too much moisture, the weld will turn the absorbed moisture into steam, allowing a substantial amount of molten metal to be expelled, which will make the weld very porous and very weak. Ferrules that have absorbed moisture can be dried by heating them to around 250 degrees until the moisture is gone.

Another thought on ferrules. Their cartons are marked with a warning that they contain silica, which can be a possible health hazard. Ferrules are commonly made from “green” fire clay with binders and then fired at high temperatures, so that there is no free silica material in respirable sizes released during the weld. When broken away from the weld, they’re basically an inert, inorganic material, similar to fire aggregate or rock, and can be disposed of. Although it would take an enormous amount of ferrule breakage and/or grinding to produce a dangerous hazard level to the operator or to anyone nearby, I thought it was worthy of mentioning.

By welderbrent (*****)

Date 09-13-2014 16:12

On my job, I am in the shop as a TPI. Ferrules are properly stored and are dry. They are not being shot through decking either. Straight to the WF or other material.

Good points though Scott.

He Is In Control, Have a Great Day, Brent

By SCOTTN

Date 09-15-2014 12:27

Thanks Brent. A couple other points with regard to weldingpolice’s reference to studs on metal deck that are worthy of mentioning, which could also result in failures…

The top flange of the beam must be free of paint and “excessive” overspray at the stud welding area.

The decking should rest completely flat across the entire surface of the flange. If there are cases where this doesn’t occur, the weld pool will run into the gaps, which can result in unsatisfactory welds to the flange and to the decking.

Also, be careful of shooting studs where the decking overlaps, so that the studs are not being shot through two sheets of decking.

By bb29510 Date 12-28-2014 21:54

7.7.1.4

By welderbrent (*****)

Date 12-28-2014 23:01

BB,

WELCOME TO THE AWS WELDING FORUM!!

I'm not sure, but I think you responded to the question Al asked about where to find ringing and acceptance/rejection criteria. If so, 7.7.1.4 is not it. That is bending, not ringing. Ringing is not found in D1.1.

He Is In Control, Have a Great Day, Brent