AWS D1.5 Qualification Test

Date 05-24-2004 16:26

I'm not sure if you are asking a question or simply making a comment here. I have done a fair number of PQR test per D1.5 . I'm not sure how the cost of RT compares elsewhere but here in central Maine, I pay about $50 for a having a 30" plate shot. That represents only about 2% of the total cost for PQR testing.
I really don't know why UT is not allowed as an alternative but that would make no difference in our case. I have had some engineers review our PQR documents, including the RT film, before they would accept our PQR, because the tests were not originally done on their behalf.
And don't forget the requirement for 3rd party witnessing. We have had times when there were no QA inspectors in our shop, so we had to pay for someone to witness testing.
Some tips that could save you some money....make sure your backing is TIGHT against the joint before welding. If not, the RT will show a line that can be rejectable and you will have to seek permission to remove the backing and re-shoot the plate.
Also have your side bends done first. Most of the PQR failures we have had were because of that. So we do them first and stop machining if they fail.

Chet Guilford

By Niekie3 (***)

Date 05-24-2004 16:39

Hi Miguel

I must agree with Chet. Generally RT is not a huge cost. Around our part of the world, it is much cheaper than performing a UT test. Where are you located? Usually places with high RT cost are small places that are not large enough to accommodate full time NDT companies. This means having to "import" these services at a premium from far-off locations.

At any rate, this is all theoretical because at the end of the day, you need to meet code requirements.

Regards
Niekie Jooste

By NDTIII

Date 05-24-2004 22:56

I personally don't see why you could not substitute RT with UT. I think the intent of the tests is to tell you if the test specimine contains defects that exceed the allowable limits. UT can tell you that as well as RT.
As long as your customer and the third party agrees, there is no reason why you can't. The only problem I would see is if you were to use the RT acceptance criteria, UT may tend to oversize your defects and cause you to reject the part, when it is actually acceptable by RT. I would recommend an alternate acceptance criteria or a technique for length sizing of the flaws.

By CHGuilford (****)

Date 05-27-2004 13:13

I just wanted to insert a caution here.....D1.5 requires RT as part of the PQR testing process. UT is nice, but is not specifically allowed per the code. At least not yet.
Naturally, a client's engineer could allow UT as a substitution for work they are responsible for. But the PQR would not comply with D1.5 completely and might not be accepted by other clients.
Chet Guilford

By miguel P (*)

Date 06-02-2004 22:33

Thanks.
Our shop is located in Venezuela.
We are talking about this RT inspection with our client (impreggillo- Astaldi). I am sure they will accept UT inspection.
Miguel P.

By Surefireinspect Date 07-09-2004 22:52

Miguel
Dont feel left out in the boonies. Iam in Hawaii and a RT cost me 135.00 per plate. I personally agree with the fellow about rt vs ut I come from a bit of the old school and can relate to a rt as a solid form of achriving the results for the future. I just finished an inspectiion were the engineer specified UT. Because I am unfimilar with the process its hard for me to understand. I rely on the UT inspector completely for the acceptablity of the weld. Some day I hope t get more involved with the UT results. I have no doubt that this is a valid atlternativeto RT testing.
Surefire

By jwright650 (*****)

Date 07-12-2004 11:33

The thing that is so hard to accept about UT, is when you find something, you don't have a real good picture to go by, only your interpetation of the signal that came back. But, when you use your training and mark it up for the welder to dig out and he finds it exactly where you said it was, it is rewarding. I can tell you, the first time you mark something up for removal, you'll be very nervous and anxious waiting for the welder to dig down to it, I know I was. With RT you have a better idea where the indication is in the part because of a physical picture. Once you go through your 40 hrs of training and get to put that training to use, UT will make a lot more sense than it previously did.
John Wright

By weldeng13 (*)

Date 07-01-2004 04:51

I think the main reason why RT is specified is that the film documents the weld and can easily be archived. I am not sure about this, but was RT a dependable and repeatable NDT method before UT? If so that may be another factor.

I also agree with Chet about acceptability to other clients, it would become a major headache and most likely result in performing another test.

Peter Kinney