American Welding Society Forum
I HAVE A QUESTION ON EXCESSIVE WELD BUILD UP ON THE FACE OF A WELD.I WORK FOR SUP SHIP PASCAGOULA QA SPECIALIST US NAVY CIVIL SERVICE AT INGALLS SHIPYARD.I KNOW FROM GOING TO THE CWI TRAINING CLASS AND OTHER CLASSES THAT EXCESSIVE WELD REINFORCEMENT CAUSES A STRESS RISER AND SHOULD BE GROUND OFF.WELL THE CONTRACTOR DOESNT REALLY FOLLOW THIS LINE OF REASONING.WHAT BOTHERS ME IS THAT INGALLS HAS MANY TECHNICAL WELDING ENGINEERS,ETC. WHO KNOW THAT THIS DOES HAPPEN IN THE SHIPYARD ON A DAILY BASIS BUT THEY DO NOT SEEM TO BE CONCERNED.ALSO OUR IN HOUSE SUP SHIP FOLKS ARE NOT VERY CONCERNED ABOUT THIS[WELDING ENGINEERS,TECHNICIANS,LEVEL3, ETC. WHAT HAPPENS IN THE CIVILIAN WORLD DEALING WITH EXCESSIVE WELD REINFORCEMENT? DON KUMPUNEN
In the areas I work, if its not visually acceptable as indicated by the applicable specification, It's corrected. If the reinforcement is not in accordance with the specifications, It should be easy to get corrected. IF it's not easy to get corrected then it may be a different Navy than the one I was in. Of course the yardbirds always had a little more leeway than we did.
The codes vary between what is acceptable re-inforcement. ASME SEC I allows 5/32" for a .250 wall boiler tube however Sec VIII and B31.1 allow less.
It's my opinion that the angle that the toe of the weld re-enters the base metal has more affect on the ability of the weld to resist certain types of failure. I don't work with any codes that mention this but I do remember the use of the term "Re-Entrant Angle" when I was in the Navy. I cant remember if it was in Milstd 1688 or 1689 or NS 250-1500 and it may have been from somewhere else.
Have a nice day
Yes, the real issue with the excess reinforcement is the angle that the weld bead makes with the base metal. Often people will grind the top of the weld flat, to meet the code requirements. This is not the intention. Those that understand that the issue is the angle, will often try to grind the toe of the weld, but usually this leads to a reduction in thickness of the base metal at the toe of the weld. This too is a problem.
What am I trying to say? Welders need to be told why certain requirements are stated. This way they will try their best to get it right the first time. Repairing this later is costly.
I have acxtually seen technical articles that show the dressing of the toes of welds with rotary files(Burr Bits) to increase fatigue life and resistance to impact loads. The base metal was actually reduce in thickness a small amount.
Have a good day
What you are referring to is called weld toe grinding and is discussed briefly in the D1.1 Commentary, Section C22.214.171.124.
Thats it. I knew I had read it somewhere.
You are correct, but then this procedure is performed under very strictly controlled conditions. (e.g. The grinding striations need to run perpendicular to the weld direction etc.) The average "repair" to sort out excessive reinforcement will be performed under much less strictly controlled conditions. (Using a large angle grinder, grinding parallel to the weld direction.) Once smoothed out, it is very difficult to observe the reduction in thickness, which could have taken place over a relatively large area. How do you try to measure this without it taking you an eternity?
A height gauge or depth gauge is used to ascertain a reduction in base metal after welding (or grinding) when access to both sides of the joint is limited. Takes a few minutes, not an eternity unless your on T&M.
Obviously it is easy and quick to measure this at a point, or to "scan" the weld here and there, but how long will it take you to perform a 100% coverage of 50m of weld, especially when the weld was "blended" over a rather wide band?
If you had as many weld inspectors as you had grinders, it would take you as long as it took them to perform the grinding, (An hour or two?) but usually you have one inspector for maybe 30 people that could be used to grind the weld.
I still maintain, you do not want to get into this territory, because you are trying to inspect quality in rather than to build it in. Under the circumstances illustrated above, you WILL miss problem areas. A thorough inspector will just miss less than the sloppy inspector.
Mr. Jooste is correct in that weld toe grinding is not a commonly applied method of weld toe dressing, and of course it has nothing to do with the correction of excessive cap reinforcement. I have seen weld toe grinding specified for highly fatigue sensitive joints that were also either ground flush with a 250rms finish and direction of grinding perpendicular to the weld axis (in the case of butt welds) or had a concave surface, also ground to 250rms finish with direction of grinding perpendicular to the weld axis for tee-joints.
The depth of toe grinding had a tight range in these cases, minimum 1mm and a maximum of 2mm. It was performed with carbide tip rotary grinders with a diameter based on base material thickness.
DGXL gives the best way to measure the depth, although I must admit there was always alot of head scratching when it came time to inspect toe grinding on a TKY.
TO ALL,ARE YOU TELLING ME THERE IS NO LIMIT ON THE WELD FACE HEIGHT IN THE MIDDLE OF THE WELD?I HAVE SEEN SOME WELDS THAT ARE EXCESSIVELY HIGH IN THE MIDDLE OF THE WELD FACE. DON KUMPUNEN
I'm not saying that. Reinforcement is measured from the base metal to the highest point on the face of the weld. If that is beyond the requirements of the applicable code, then it would be un-acceptable.
Look at D1.1,I can remember catching hell from inspectors for build up on moment connections,Now with the seismic code you must put on an extra fillet on top of the full pen weld.I think good blending technics of common sense shoud be used when joining ood sized sections.
Late as usual on this matter but check out Section 5.24.4 D1.1:2000. Unless otherise specified butt, corner joints etc, face reinforcement shall not exceed 1/8" in height. It further states all welds shall have a gradual transition.
I have had inspectors go both ways as to excessive reinforcement. From a fabrication stand point excessive welds anywhere is costly in time and money. So what code are you working with?
I AM WORKING TO MIL-STD-1689 WHICH IS USED BY THE US NAVY IN SHIP BUILDING. THE CONTRACTORS WELDERS PUT IN A LOT OF WELDS USING FCAW THAT HAVE EXCESSIVE WELD FACE REINFORCEMENT. DON KUMPUNEN
Are you dealing with fillet welds or groove welds or both? It seems transition is the key to blending without undercut. D1.1 gives clear cut examples and dimensions that are not to be exceeded. Does the code you work to give you this type of info to inspect by? D1.1 merely states in paragraph 126.96.36.199 that the excessive weld metal "shall be" removed. Paragraph 5.26 gives examples of the ways this material can be removed, and says additional weld metal shall be deposited to compensate for any deficiency in size. I'm not sure I completely answered your question, but I hope I helped.
I do not have any information on Mil-Spec but I re-read your original post. Because you mention "weld reinforcement" I assume you are only referring to grove welds. This is controlled by D1.1 to 1/8" max for butt and corner joints. (5.24.4).
Another interesting point is in FEMA-353 this is a post Northridge Earthquake study on CJP joints. Section 5.7.1. only allows 1/32" of face reinforcement to be left.
Also see figure 5.4:2000 which shows acceptable weld profiles.The convexity of a fillet weld is also addressed but increases with weld size.
In reference to how it is handled in the private sector - We have had excessive face reinforcement called to the attention of several welders especially with NR232 (E71T-8). If the welder is unable to control this he may be faced with re-test or for sure lots of grinding. Some inspectors do not mention this but it does create a stress riser and AWS does not allow above 1/8".
If the Mil-spec you are under specificies AWS D1.1 for standards then have your contractor grab his grinders - he will see to it that the welders refine their techniques.
Hope this helps.
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