UT help

[bob74r]

Building piping to ASME B31.3. Client spec requires that all branch connections have 100% MPI and 10% UT. Have tried a specification deviation to allow only MPI which was approved but only for piping with wall thickness less then 3/8".

Had a stub-on "Straight piece of pipe beveled end full pen weld" fail UT now as code calls I am require to have two tracers.Weld failed for incomplete penetration.

Now here is where I'm running into issues.
Only other branch type welds this welder has complete is one stub on some make as failed weld and olets.

The one stub on has a massive re-pad currently welded on top of it. After speaking with NDT contractor they claim that this weld can not be UT.

Now as for the olets (These sit up top of the pipe with a diagonal full pen from the olet to the hole cut into the main run of piping. Current UT guy claims these can not be inspected but means of UT. So as it stands right now i'm hooped for tracers and client does require inspection on olets.

Now my question would be is UT on olets actually possible or am I dealing with a poor technician?
Reason I ask this was 5 months ago on a different job same type of olets same NDT company just a different office had no issue performing UT these olets with a straight beam looking for IP which is about all you will be able to see. We were actually receiving reports stating accept or reject on these welds with identical geometry. So are these reports actually legit? Someone here is giving us false information

Anyone had any experience with this?

 

[gtaw]

I think the reinforcing pad is the problem. The UT is only going to penetrate the reinforcing pad and will never reach the run pipe using straight beam interogation.

Your use of jargon doesn't exactly help me understand the joint configurations or your problem.



Best regards - Al

 

[weldtek]

I'm having a little trouble picturing the joint in question. Usually the weld on an o'let would have an exterior surface profile not conducive to UT scanning, however, if the inside was accessible and ground flush, UT could be performed from that side.
I'd suggest you have the Level III come out and give you his opinion.

 

[Mr168]

I see this situation quite a bit. Client-spec'd NDE requirement, and a combination of factors that make it unfeasible for a given joint.


Contractor says the joint configuration isn't doable. Even if it IS physically possible to UT the joint, the contractor's position is a good indicator that there is a strong possibility of you getting false indications/incorrect readings. End result - you go cutting and digging into a weld, find nothing, waste a lot of time and money, close it up, and repeat the cycle.

Or, you take the easier option, and send the client the specifics of this particular scenario, along with the contractor's response, and allow them to provide you a suitable means of addressing the situation that will satisfy them. If they say "hey, this should be doable", then you can look at sub'ing the UT out to someone else or discussing it further with the contractor.

 

[deco0404]

Bob,

it is plausible they are both right. Ut is not an ideal test for olet's, but you can detect IP depending on thickness ( very important ) and diameter.! The problem with these types of weld is that a good deal of the weld is above the pipe and this part is very difficult ( if not impossible ) to fully examine. You can tell if the weld is fused or has penetrated the pipe, but not the weld reinforcement.

As for reporting, you shouldn't issue a report saying that the weld is ok by Ultrasonic testing when only a 0(zero)degree compression probe was used......you would need at least a 45 & 60 or 70 degree probe to make a complete evaluation......

how this helps a little

Declan

 

[stanweld]

UT is a poor choice for detecting IP on set on branch connections. A better method is visual using a boroscope.

 

[tidraie]

Olets are inspected by magnetic particle and /or liquid penetrant inspection. As mentioned above one can do a complimentary inspection with the use of a boroscope to see if the weld has a full root penetration.

The use of UT on this type of joint preparation can only give you a partial inspection and that is worth what it's worth.

Need more info? Just ask.

André

 

[PAN]

How about MT or PT on the root pass? Please comment...

 

[tidraie]

Yes, MT or PT can be done on a root pass. But a final inspection must be performed after final pass (cap) . The inspector must then add on test results that the inspection was carried out on initial weld pass root pass and final weld pass. This practice is often used on heavy piping and multiple weld passes (8 passes and over).

Andre

 

[vanmorrison]

Yes Mt/Pt can be done on a root pass but unless you are performing the inspection on the inside you will not detect IP at the root.

What is the inspection criteria?

Depending on the thickness of the material (min 5/16") and the diameter( min 1 1/2"), and the curvature, Sectorial Phase Array could be utilized to sweep the root to detect IP.

Boroscope is an excellent tool for inspection if you have access but the client is requesting UT. What are you looking for?

Depending on the configuration RT in lieu of UT might be an option for consideration.

 

[Duwe6]

I vote for borescope and a better/more aggressive UT tech.

I can and have UT'd nozzles successfully. All returns need to be plotted on grid paper to insure that you know where the return is coming from. Unless the vessel/pipe engineer came up with a mismatched nozz & repad -- medium-to-thin nozz pipe welded into a thick repad -- UT is doable. Results should be written up as "Client info" unless a Level III signs off on your technique.

Borescope is MUCH better than MT or PT of root pass of O'let or nozz. MT & PT only reveal surface-breaking defects. The most probable defect and worst defect is Incomplete Penetration. IP cannot be detected with MT or PT. On the O'let-to-vessel or header weld, it cannot be detected with UT. Your field QC Inspector should have looked at the root [dental mirror & flashlight] of the O'let weld prior to having the branch pipe fitted to the O'let. If he wasn't there, shame on him. If he did not have the authority to require the welder wait to fit the branch pipe until the O'let root was inspected, shame on you. An inspector on a 'short leash' cannot keep these problems from constantly cropping up.