UT Testing Requirements for Tubular T connections

By ejohn90472 Date 02-23-2009 00:28

To everyone:

I have a current project that has numerous Structural Steel brace frames whose tube steel (A500 Grade B) columns are to be full penetration welded (with backing) to 1-3/8" flat base plates (A36) or embedded WT's of various sizes in the horizontal position.

Per the approved design drawings all full penetration (CJP) welds are to be ultrasonically tested. My question concerns the corners of the HSS tube steel columns to a flat A36 base plate - are corners of tube steel columns required to be ultrasonically tested per AWS? If so - where is this stated in AWS D1.1?

Could you please clarify what section of the AWS D.1 welding code requires UT testing of corners of tubular connections? Thank you

By kipman

Date 02-23-2009 23:39

John,
There is no requirement anywhere in D1.1 that requires this type of weld to be ultrasonically examined. Any such requirement has to come from the Engineer. If the drawings specify UT, then that means it was required by the Engineer. If the drawings do not specifically exclude the corner areas of these square or rectangular tubulars, then that means they also need to be UT'd.
The problem with that is that it is not possible to do an effective Section 6 UT due to the small radius at the corners (the main problem is the large transducer shoe size required by Section 6 and the inherent coupling problems, though sizing of detected discontinuities is also a problem is using Section 6). Do a search and you'll find some other threads on this.
This will likely require that somebody get the Engineer to clarify the requirements. Possibilities are to exclude the corners (though if I were the Engineer I wouldn't do that - we've all seen how welders like to stack up their starts & stops in the corners) or to clarify the techniques and acceptance criteria for UT of the corners.
Mankenberg

By ejohn90472 Date 02-24-2009 03:27

Kipman:

The design drawings state that all CJP welds are to be UT'ed however it does not mention the corners as being excluded or included. The Welding Inspector feels that the corners do not require UT inspection citing numerous challenges in trying to perform such a test. I am not fimilar with this process and am looking to those that have experience in UT. Your feed back is greatly appreciated. If you have any other guidance on where I can find additional information I would greatly appreciate it. Thank you

john

By kipman

Date 02-24-2009 16:28

In my opinion the welding inspector is correct in that UT of the corners is difficult. However, and also in my opinion, he is dead wrong if he believes that fact in and of itself means that you don't have to UT the corners. That is the Engineer's decision and has absolutely nothing to do with the opinions of any welding inspector.
Think about it from this point of view - the Engineer believes that these welds are important enough that they are specified to be CJP and they are required to be UT'd. The corners are the most difficult portions of these joints to weld (this can be surmised by additional welder qualification test requiring a macroetch that is required for box tubulars). Why would the Engineer simply say that it is okay to not inspect the most difficult portion of the joint to weld, simply because it is difficult to inspect.
Anyway, this is the Engineer's decision.
Mankenberg

By CWI555

Date 02-24-2009 16:36

I've performed this in the past, but your not going to do it with the standard AWS setup. Your weld inspector is stepping out of his or her bounds stating so in the manner you quote. The only really difficulty I see is that the engineer needs to be more specific with requirments and will likely need a D1.1 experienced LIII UT hand to design the test around the given acceptance criteria.

can it be done? Yes
Is it easy? no

Regards,
Gerald
CWI
LIII UT, MT, PT, VT, RT