excessive grinding on weld toe

By swnorris (****)

Date 03-26-2008 10:58

In case of no requirements, it should be at the discretion of the EOR, not the inspector.

By new tito (***)

Date 03-26-2008 12:49

I would write an NCR, especially if the grinding depth exceeds the acceptable undercut limits. I would also explain the concern about the depth, in regards to the criteria for undercut (if undercut is rejectable at 1/32", why should we allow grinding beyond this depth), just in case you're dealing with an idiot that signs off on NCR's.

By js55

Date 03-26-2008 13:51

Keep in mind that if you have no criteria you have no justification for an NCR. How could you. What are you NCing to if there is no criteria to detemrine a C from an NC?
If there is a concern, then the proper authority should be made aware. This is entriely ligit, and well within the responsibility and authority of the inspector.

By jwright650 (*****)

Date 03-26-2008 14:04

I agree...if there is nothing to judge whether something is acceptable or not, you don't have any criteria to base your findings on. Listing it as a concern of your's in a report of inspection is definietly the way to go. You have performed your job as an inspector and the descision will be for someone responsible to make the call.

By waynekoe (**)

Date 03-26-2008 15:35

I don't know about that. I feel that there is always a code to specify weld quality, whether stated or not. Its the code of practical standard practice. Everone out there that has anything to do welding can tell you that you can't develop the full strength of the steel if the groove isn't filled out, or, the fillet isn't the required size. To fall back on the excuse that there isn't any governing code to inspect to, when you know the weld has been undercut by grinding, or, I guess, would now be underfilled, is a load of crap. We, as professionals (welders or inspectors or both), know whats good and whats not, and not applying that knowledge because of no presiding code is a cop out. Good is good and **** is ****. Just my opinion-Wayne

By js55

Date 03-26-2008 19:39

Wayne,
"We, as professionals (welders or inspectors or both), know whats good and whats not, and not applying that knowledge because of no presiding code is a cop out. Good is good."
So if I were to receive a specification that concisely stated ya'll know whats good. Just do it. That wouldn't be problematic? :)

By waynekoe (**)

Date 03-26-2008 20:13 Edited 03-26-2008 20:33

Firstly, anybody stupid enough to write that in a spec would deserve what ever they got. And secondly, the original post said something about "in case there is no requirement". So no, I don't find it problematic, and, if at this stage of the game you don't know what constitutes a good weld, your in the wrong business. Would you by a trailer hitch with ground out weld toes? Most likely not. So I stand by my comment, we do know what constitutes a good weld and voice our opinions each time we walk into a store or some other office building, by a home built trailer or carnival ride (reference FC07). And further more, if I was someplace where they wrote specs with "Y'all" in them, I'd shoot myself, or at least start doing drugs again.

By js55

Date 03-26-2008 21:06

Just messin around Wayne. Although, i just don't have as much confidence as you do when it comes to an inspectors refrain when utilizing one of those self justifying 'rectumus extracticus/I'm the mommy thats why' codes.
As John indicated not all things in real life are so clear. Thats why we need specs and why inspectors authority is by necesity, limited. An engineer is an engineer and an inspector is an inspector. I believe the segregation is a good one.

By waynekoe (**)

Date 03-26-2008 22:30

I hear you there, brother!

By jrw159

Date 03-26-2008 16:24

Here is my take on this, and purely opinion at this time. What is undercut? An area at the toe of the weld that is lacking filler/base metal. When you file the toe of a weld you are removeing filler/base metal. The results are the same no matter how you produce this void of material. In my opinion, when the toe of a weld is filed it should be held to the same criteria as undercut. I have done B31.3 and B31.1 inspections in the past and have run across this practice a few times. Every time I saw this used it was to try to hide/mask the undercut produced during welding and I have not been able to come up with any solid backup to show this practice as neccessary or acceptable.Where does the welder come up with the notion that he is allowed or is required to remove base metal from the toe of the weld??

By jwright650 (*****)

Date 03-26-2008 16:52

The undercut when left by itself presents a stress riser, therefore grinding smooths this transition and removes the stress concentrator. Excessive grinding is subjective to whomever is looking at the weld, the welder thinks he has done a good job, the inspector thinks it is excessive, now who is to say who is correct? Without a governing code you now have an inspector or the welder splitting hairs trying to decide the acceptability.....that is why we have governing codes to keep us in the middle of the road and out of the ditches muddying up the waters.
My opinion.

By hogan

Date 03-26-2008 16:59

Our shop doesn't work with a lot of pipe, mostly plate and shapes. I typically hold this type of thing to the criteria of A6.

By jrw159

Date 03-26-2008 20:06

I can understand the reasoning for the transition, and have seen this in the past for very minor touch up. What I was refering to, I think but not for sure, is commonly refered to as "wedding banding" the weld. This is accomplished by using just the sharp edge of the file to produce a groove in the toe of the weld with very little transition. I never got deep enough into it to find out why it was being done, other than verifying through EOR that this was not wanted, due to the fact that the few welders that I found doing it could only tell me that they had done it for years, with no valid explination of why other than they thought it looked good. Better than the undercut in thier opinion, I guess. But on to the real issue. I believe that one could make a determination of acceptance based on material thickness tolerances for the material in question, as well as the acceptance criteria for whatever code you may be working to, in this case I believe it was B31.3 and if the depth of material removal at its deepest point exceeds the criteria for both material and weld then I would venture to say that it is rejectable. Very good point about transitioning the stress risers.

By jwright650 (*****)

Date 03-26-2008 20:24

I agree that if the through thickness has been reduced, then too much material was removed. My point really is more to do with not having any criteria to go on other than an inspector who thinks this is a concern and that in his opinion it should be rejected and repaired. It may very well need to be repaired, but what do you base this on other than his opinion? That's all that I was saying, when it gets tricky is when it is a borderline case, what do you do then? I still feel somebody in authority like the EOR should make the call, unless they give the inspector free reign to do as he/she sees fit and can trust that is the correct decision.

I've been a CWI for a number of years now and have seen outside inspector come into my shop and want to argue the size of one fillet weld out of thousands. Then I ask them to show me and they can't even use the filletweld gage properly, and then they tell me that they thought it looked low....this is why I take opinions with a grain of salt. I'm alot like Joe Kane in that I need to see it in black and white...and trust me, there's no grey stuff with him.(NBL Joe)

By jrw159

Date 03-26-2008 20:48 Edited 03-26-2008 21:09

I totaly agree. The question is "what is the criteria, and does it even exist?" I believe it does. Mill certs to verify material. Material specifications listing the thickness tolerances for said material. Customer specifications, and last but not least, code. With this information you can make a determination. For example, and these are just #'s pulled from the sky, and nothing stated in any code anywhere, lets say we are welding two 1" X 30" X 10' pipes together. The thickness tolerances for this material is plus or minus 1/4". Acceptance criteria for undercut as listed by code is 1/4". The material has been removed to a depth of 5/16". This would be unnacceptable.

Would the documents and records stated not be available or not exist? Key to the original post is "B31.3" So it would be my guess that under circumstances requireing this code that yes they do exist and are available. imho of course

btw I am a black and white guy myself. I HATE grey areas. That is why I love being an inspector. D1.1 / B31.3 / B31.1 do not leave much to the grey area if inspectors have been trained properly to read codes.

By Jim Hughes (***)

Date 03-27-2008 14:04

John,
I agree with your post. I would add this. The original post said it was B31.1 they are working to. It gives clear direction on undercut, acceptable and unaccepable limits. I think it would be easy to dertermine if it's undercut in the as welded condition or self induced by grinding and that's how I would make the call. Nothing that a V-Wac gauge could not discern.

Also I think we find ourselves in real trouble if we start making calls based on the "code of practical standard practice" that was mentioned in this thread. I think I would have to go to work as a greeter at Wal-Mart if I saw a drawing that said inspect to the code of practical standard practice. :)

Jim

By waynekoe (**)

Date 03-27-2008 15:22

Jim, please. Don't take something out of context and try to beat me over the head with it. The only point I was stressing was if asked for an opinion, we, as welders and inspectors, know what constitutes a a clean, sound weld. We see read about them every day, hence, the code of practical standard practice. It,s a figure of speach. If your neighbor came to you and asked your opinion on some welds he just made, would you say?-"I can't have an opinion on your weld unless I'm told what code you welded to!" No, I don't think you would. But, if you find your self in trouble for having an opinion, then you should be at Walmart, because you know full well you'll never see a drawing that says that. I feel dumber for even having read that in your reply. And remember, this is all in great fun! Wayne

By Jim Hughes (***)

Date 03-27-2008 16:19

Sorry about that Wayne. Please except my appoligies. No offence intended.

Jim

By waynekoe (**)

Date 03-27-2008 17:43

No apologies required-and no offence taken.

By jrw159

Date 03-28-2008 13:23

Jim,
Not trying to pick you apart, because you are right, except the original post concerned B31.3. This however makes what you have stated even more valid, imo, because I believe the requirements are the same for undercut, and B31.3 is a more critical application than B31.1, to my knowledge.

By Jim Hughes (***)

Date 03-30-2008 12:28

John,
My bad. good catch.

Thanks
Jim

By Joey

Date 03-26-2008 17:00

Instead of repair welding on undercut...... I guess the welder used files to remove the undercut which caused excessive grinding. If that is the case, I would suggest to the piping or welding supervisor not to issue files to the welders.

Excessive grinding will reduce the thickness of the base metal, consequently, will reduce the corrosion allowance. To me, I will accept it if there's gradual transition and if it is not more than depth of allowable undercut.

If NCR is not appropriate then write it in the punch list.

Regards
Joey

By pipewelder_1999 (****)

Date 03-26-2008 21:29

In addition to the fine responses let me add a little opinion.

The project engineer could be consulted. The piping was designed with a minimum wall thickness requirement. This could be a value used to express concern with the condition. Not accepted or rejected but addressed.

Some companies use a system for requesting information in area in which the information is not clear. I have seen it referred to as an RFI (Request for Information) form. No acceptance or rejection, just getting the required parties on board with what is happening.

Undercut and reduced base metal thickness are two different conditions. I have seen some standards in which a rounded profile is suggested at the toe of the weld. The actually reduces the stress concentration.

A reduction in base metal thickness around the circumference of a pipe designed to hold pressure is not as detrimental as it would seem. The majority of the stress in a pipe is hoop stress (trying to open the pipe along the centerline). This does not take into account any stress generated by forces other than pressure.

B31.1 Addresses this as below

(C) As-welded surfaces are permitted; however, the
surface of welds shall be sufficiently free from coarse
ripples, grooves, overlaps, abrupt ridges, and valleys to
meet the following.
(C.1) The surface condition of the finished welds
shall be suitable for the proper interpretation of radiographic
and other nondestructive examinations when
nondestructive examinations are required by Table
136.4. In those cases where there is a question regarding
the surface condition on the interpretation of a radiographic
film, the film shall be compared to the actual
weld surface for interpretation and determination of
acceptability.
(C.2) Reinforcements are permitted in accordance
with Table 127.4.2.
(C.3) Undercuts shall not exceed 1/32 in. (1.0 mm)
and shall not encroach on the minimum required section
thickness.
(C.4) If the surface of the weld requires grinding
to meet the above criteria, care shall be taken to avoid
reducing the weld or base material below the minimum
required thickness.

I'll look through my B31.3 to see if I see anything.

Have a nice day

Gerald Austin

By CWI555

Date 03-27-2008 14:08 Edited 03-27-2008 18:39

Gerald,

Just trying to stick to the quoted code. B31.3. No edition was listed, so I'll use 04.

328.6 Weld Repair
A weld defect to be repaired shall be removed to
sound metal. Repair welds shall be made using a welding
procedure qualified in accordance with para. 328.2.1,
recognizing that the cavity to be repaired may differ in
contour and dimensions from the original joint. Repair
welds shall be made by welders or welding operators
qualified in accordance with para. 328.2.1. Preheating
and heat treatment shall be as required for the original
welding. See also para. 341.3.3

341.3.3 Defective Components and Workmanship. An
examined item with one or more defects (imperfections
of a type or magnitude exceeding the acceptance criteria
of this Code) shall be repaired or replaced; and the new
work shall be reexamined by the same methods, to the
same extent, and by the same acceptance criteria as
required for the original work.

344.2 Visual Examination
344.2.1 Definition. Visual examination is observation
of the portion of components, joints, and other piping
elements that are or can be exposed to view before,
during, or after manufacture, fabrication, assembly, erection,
examination, or testing. This examination includes
verification of Code and engineering design requirements
for materials, components, dimensions, joint
preparation, alignment, welding, bonding, brazing, bolting,
threading, or other joining method, supports,
assembly, and erection.
344.2.2 Method. Visual examination shall be performed
in accordance with the BPV Code, Section V,
Article 9. Records of individual visual examinations are
not required, except for those of in-process examination
as specified in para. 344.7.

(least anyone get any bright idea about not recording individual weld exams for VT the finished joint is listed under 344.7)

344.7
(f) (for welding) slag removal and weld condition
between passes
(g) appearance of the finished joint

There is a marked difference between the requirements of 31.3 and 31.1.

My interpretation:
Unless the EOR has specified something other than Base 31.3 requirements, repair by grinding is not permitted by this code. (see quotes 328.6 and 341.3.3)
Care must be taken here for the following reasons;
There is nothing in B31.3 prohibiting "work in progress dressing of the weld". However; if it's been turned over "officially" for inspection, anything found to be defective per
"Table 341.3.2 Acceptance Criteria for Welds and Examination Methods for Evaluating Weld Imperfections" would have to be repair "welded" per the requirements of Para. 328.6. (341.3.3 "shall be repaired or replaced") (328.6 "Weld Repair: A weld defect to be repaired shall be removed to sound metal. Repair welds shall be made using a welding procedure qualified in accordance with para. 328.2.1, recognizing that the cavity to be repaired may differ in contour and dimensions from the original joint. ")

Up until the time the weld is "officially" turned over to inspection, there is no code based specific instruction other than using a qualified WPS and welder for making the weld.
This is were experienced foreman and welders come into play. If that welder/forman or anyone other than the inspector notes undercut in excess of whats allowed by code before inspection turnover, *there is no prohibition that I can find for blending it in as long as min wall is not violated, a smooth transition is maintained, and any variables for welding are not violated.
In my opinion, this is the reason for a "clear and concise to all" understanding of 'at what point the weld is turned over' is needed.

Production owns that weld until it's turned over except for matters specifically addressed in para 344.7 which leaves plenty of room for interpretation.

If production turns that weld over "officially" and it contains anything that can be rated as a "defect" There is no option given by the code alone for anything other than repair by welding in B31.3 04 edition. Conversly, if it's found "in process", removal of the stress riser by grinding is not prohibited. Therefore if it was removed prior to 'official turnover' by grinding it was in process per *, no undercut/riser exist, the inspector has no basis for reject and the weld passes visual.

That all may sound chicken SH**, but the inspector does not have the option to insert common sense or opinion and must stick to documented requirements. If production doesn't understand that, it's their problem, not the inspector. Bottom line is, it is what it is when it's turned over to inspection. Production has considerably more leway to put a handle on these problems, but they have to recognize it for what it is first.

My opinion and interpretations for what it's worth
Gerald

By pipewelder_1999 (****)

Date 03-27-2008 15:16 Edited 03-27-2008 17:11

I agree with what you stated above.

Thanks for the effort and your time.

Have a nice day

Gerald Austin

By js55

Date 03-27-2008 19:19

WOW Gerald. That was quite excellent.

By jrw159

Date 03-28-2008 13:24

Very well spoken.

By Richman (**)

Date 03-29-2008 09:27

Thanks for the brilliantly details you give to us Gerald. And thanks for your valued times and effort you share not only to me but too many inspectors who wants to clear things like this on this forum.

By Joey

Date 03-30-2008 17:42 Edited 03-30-2008 17:44

I don't understand the need to offer "officially".... I've seen toe cracks being repaired without prior approval which welding operation / contractor claimed as minor undercut only. With the welding inspector on the site during welding work, it is possible for any unusual activities or repair to be noticed. Visual examination during welding is often required, it may not be specified in the code but is common practice for high-quality work. In many situations repair work, must be described and approved prior to doing repair the work.

Regards
Joey