Clad defects & radiography

[nktqc]

Hi friends

Well here is the case -

After cladding of pipe and flange with all approved WPS we carried out NDT ( UT for dis- bonding and PT for open surface defects as per approved procedure with approved NDT technicians ) and same was witnessed , accepted and released by vendor inspector as well as client inspector also for spooling activity.

After butt welding ( Flange to Pipe ) we took RT for butt weld and we found some linear line ( having width more nearly 2~3 mm ) and porosity ( dia nearly 6 ~ 7 mm ) in clad area. Kindly note that butt weld area is free from any defects/ indication.

Questions are -

1- Is this clad defects treated as butt weld defects ( acceptance and rejection )

2- If this clad defects are rejected then what about those cladded area where there is NO RT ?

3- what would be rejection / acceptance criteria for clad defects in radiography ? ( kindly refer if any code is there for RT in cladding )

further more information on this issue is hearty welcomed.

Thanks

 

[ColonelSanders83]

For starters, the code with the aceptance criteria you are working to is needed. Are you talking BPVC? API? Maybe a foriegn to the US application?

I'm sorry to say, but I suspect you are in grey area here. The safest thing to do would have been to do your flange to pipe weld first, then done the radiography of the joint, then performed all your cladding and cladding inpections. As it stands you have a joint failing criteria due to a more stringent than required inspection. This is always tough to get around.

I wonder how you made the butt weld without first removing the cladding in the area behind the weld? Is your weld procedure qualified for bimettallic welding?

I would have thought the cladding would have been removed in the vacinity of the butt weld prior to making the weld and inspecting it (RT), with the final step after the required radiography being the application of cladding in behind the butt weld, and then perform cladding inspection.



A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[nktqc]

Dear Sanders

I will try to reply on your query / suggestion point wise

1- Code we are using are BPVC , B 31.3 for spooling , for cladding there are several MECS's , shell specs , Client specs , and of-course materials related codes.

2- Well , after spooling its almost impossible to carry the cladding , kindly note that i am talking about spooling also which are having sizes vary from 6" to 48" with lots of elbows , tee's , flange joints and so on.

3- I am talking about CRA clad , and if we remove the clad from joint area then there is NO us of cladding ( as we loose corrosion protection )

This is the clad pipe fabrication ( spooling ) , we are doing the cladding of flanges , fittings ( elbows tee's , reducers )and pipes , and then carrying the spooling work.

I hope above information will give some clear picture. As for as approval , we are using approved WPS , Procedure and methodology for cladding and spooling.

Thanks

 

[ColonelSanders83]

Ok, this clarifies matters a bit (I have attached a sketch of what you appear to have)

Here is how I would procede.

Hello Mr. Owner, the butt welds have all passed radiograpgy, Here are the prints. Please approve.

If Mr. Owner rejects the welds based on the indications shown within the cladd regions, demand the rejection criteria (thier basis for rejecting the weld). Mr Owner will likley state that you have indications of these sizes and based on BUTT WELD criteria you have failed and must repair.

At this point you will need to take a hard stand. It is imperitive to point out that the indications are not within the butt weld, but rather in the main component cladding. The main component cladding has alredy passed its inspection criteria and has been approved. Radiography is not an inspection criteria for cladding (confirm your contractual requirements for inspection, you need to be %100 sure that you have no contractually invoked acceptance criteria for radiography of cladding).

The thing you must keep in mind is that you have indications on a radiograph for which you have no acceptance criteria.

Additionally these indication do not fall fall within B31.3's definition of the weld. See the interpretation below.


Interpretation 11-01
Subject: ASME/ANSI B31.3-1987 Edition, Para. 341.4, Extent of Required Examination
Date Issued: May 22, 1992
File: B31-91-034
Question (1): In accordance with ASME/ANSI B31.3-1987 Edition, para. 341.4, when applied to the radiography of welds, what areas, in addition to the weld, are to be included in the "area of interest" for interpretation and evaluation?
Reply (1): The Code does not specifically define "area of interest."

Question (2): Does the term "weld" include the base metal heat affected zone adjacent to the weld deposit when applied to radiography?
Reply (2): No. See the definition for "weld" in para. 300.2.

Now, keep in mind Mr. Owner may demand it be repaired. At this point you will need to fall back to the contractual requirements. As long as you are %100 sure you are not contractually required to perform this examination, I would hit them up with an appropriatly massive change order for the repair.

Additionally I would provide the cost to radiograph everything and an hourly rate for repair of any further defects found. As the owner is now specifying more than they originally contracted for it is entirely appropriate for them to pay for it.

I only see one major problem to the above argument. I hope these flaws were acceptable or otherwise not an issue for the original UT disbonding inspections. If the UT inspections you performed should have caught this you are gonna be stuck fixing the flaws at your cost.

Just My two cents worth

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[nktqc]

Sanders , awesome reply ..

Thanks a Ton

I got it.

Now let me try

 

[ColonelSanders83]

Any Word?

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[nktqc]

Hi

finally client is NOT accepting , so we have to do the re-work or reject the cladded items.

Any way we had a very good and informative post and a lot thanks.

Regards

 

[ColonelSanders83]

Just out of Curiosity, what is thier basis of rejection?

Did they have any contractual requirements on the matter?

It seems to me that would be an expensive fix that you are very likely to have reoccurances on. I would fight this issue to the death if it happened to me.

Just my two cents worth.

A question properly stated is a problem half solved.

Always remember, free advice is worth exactly what you pay for it!

http://www.ap-dynamics.ab.ca/

 

[stanweld]

If the cladding is included in the strength calculations, defects related to the cladding in the weld subject to RT must be included and repairs required. If the cladding is not included in the design calcs, RT the strength weld before clad restoration. After confirming sound, complete the clad restoration. If you must provide a weld from one side only into the clad section as well as the base metal and RT is required and the defect therein conjoins the strength weld, you should repair. Finally under B31.3, the Owner's Inspector must be convinced as to the necessity of repair.

 

[nktqc]

ColonelSanders

Well there was nothing mentioned in contracts except Company can ask for alternate or another NDT method if required and based on this they firmly said to repair and rejection is based on B31.3 ( as applicable for butt weld )

 

[nktqc]

dear stanweld

here cladding is not included in the strength calculations, its only for Corrosion protection.

Here question is , for cladding there is UT and PT , but not RT , and after butt welding we are going for RT of butt weld as required. Any indication which is coming in weld or originating from weld and going to HAZ or HAZ to weld , as per applicable codes ( B 31.3 and Section VIII ) we are repairing / attending.

But for clad Is we really need to apply above codes for rejection ?

As cladding is only for corrosion protection then how come soundness of butt weld required for cladding?

Finally , if company asking to repair we have to do , ultimately codes also silent or favoring company.

Regards