I felt like this was a very good article and look forward to the next 3 parts. But I have a few questions for other UT inspectors in the forum:
1) It states that "...Nonprequalified welds and certain combinations of prequalified welds cannot be inspected without specifiic NDT Level III written instructions." Where is this stated in D1.1? I don't find that. What is meant by "prequalified? Joints for which a pWPS can be written? Do you interpret that to mean, according to the author(s), that any weld that you have to test to qualify (non-prequalified) would require a specific procedure by the UT III? Where is that in D1.1?
2) It states "Inspection is limited to 27° - 125°F without an NDT Level III approved procedure." Again, I don't find that in D1.1. D1.1, 6.11 states NDE may begin immediately after the completed welds have cooled to ambient temperature. But that is only "limiting" temperatures I see. I have been guilty of inspecting and/or reinspecting a weld when still warmer than ambient, but only when a hand can be put onto the steel without being burned. Couplant does not last long on warm steel anyway, not to mention possible transducer damage on hot steel.
How many UT IIs here have had the specific and practical exams as discussed in the article and required in 6.21? My specific would qualify. But my practical exams was only to see if I could find and determine acceptability of a discontinuity. He did not really look at my report to see if I filled it out completely or accurately.
How many other UT IIs document their periodic calibrations/verifications during the day? Based upon my Level IIIs recommendation, I started doing that last year, but have never been instructed to do that anywhere I performed UT previously. Told me to record specific values whenever I performed the start of day, "30 minute" recalibration checks and end of day checks. I made a form to attach to my field report form to record the data on.
How many other UT IIs perform and document (do it yourself) the calibrations required in D1.1, 6.30? I have all my records to back up my instrument (except the one that is now overdue to be performed) since we purchased it and put it into service. I used to manage a calibration company and several companies would send us their UT flaw detector (usually the machine only, without any transducers), for us to verify for them. But they only sent them in annually. Guess that means they only used their instruments about 40 hours per year. Wonder who did the rest of the machine verifications for them.
How many UT IIs ALWAYS perform the longitudinal scans of the material that sound will be passed through? Guilty as charged. If I am honest, I often get lazy and skip it. Takes to much time and effort. Guess I will have to do better in the future.
I have been doing UT on and off and on again since 1986. Been to Krautkramer UT I and II back in the 80's. Lobbying my boss to go back for their Weld Inspection 4 day class in March (http://www.geinspectiontechnologies.com/services/Training/training_price.html). Has anyone else attended this class? Did you get your money's worth from the class? Feel I (and my company) would benefit and gain much needed confidence from some additional weld inspection training. Sorry for rambling, but looking forward to feedback from other UT IIs and IIIs.
Doug: You brought up a lot of good questions and concerns. I haven’t read the Trends issue yet. For now I'll give some feed back about my experience with taking a weld inspection class.
In 2002 I was coming from an aviation NDT background moving into the weld NDT industry. I took the Hellier 40-hour weld inspection course in Houston. Although it gave me 40 additional hours of formal UT training and a training certificate, the class did not measure up to my expectations. The first three days were a re-hash of UT II. We did not get into the ASME code until Wed afternoon of that week. There was no time spent on D1.1 other than to cover that it existed.
The late portion of the afternoons was spent on weld specimens and cal blocks. A little hands-on is better than nothing.
My expectations were that the course was intended for Technicians with UT II capability. I expected to do weld inspection on pipe and plate of different thickness’ and materials. I also expected to cover report writing in detail but that did not happen. I expected that the course would cover UT inspection in the Power and Process codes along with AWS D1.1 and the different sections of ASME. I expected that the course would cover all the cal blocks needed to do inspections on the different product forms and codes. I expected too much.
My lessons learned is that I will inquire more deeply into what a course covers before shelling out the bucks. That course was 950.00 then. It has increased since. Also not to offend Hellier or the Instructors, I want to tell you that Hellier and their Instructors are among the best. The course material was disappointing and I am sure it has since changed. If it wasn’t for the three days of the UT II re-hash, I beileve that I would have gotten my monies worth.
Regards, Donnie Mann
I also felt the article was very good. I wish they had published the topics for future articles.
We have a Quality Assurance Manual covering all NDT methods and techniques performed. This manual is submitted and approved by the clients Engineer, QA Manager or Level III. The manual is written by a Level III and fulfills the defination: "NDT Level III written instructions". I took the term "nonprequalified" to mean tecniques other than those in Table 6.7. as well as in the body of the code. For example when I change techniques to evaluate a particular indication, that is noted on the report.
I also wondered about the 27° to 125°. 27° is an odd number to pick out of the air. Have to look into that one.
AWS specific and practical exams are overlooked by many companies. I have taken them for years and they are an adder to the Level II specific and practical exams. (Some are very easy) Generally, they are about 30 questions on the UT sections of the AWS code, many are just fill in the blank with the paragraph number. A sample report has always been part of the exams, as is a demonstration weld or mock-up. I recall most companies using a 10 point checklist to evaluate equipment set-up, calibration, scanning & evaluation.
We note the periodic calibration information in a daily journal only (along with reference dB, and other variables for the daily report) but do not include it in the daily report. In 28 years, the clients that wanted it had their own form to record that information.
I send scopes out for an annual calibration and cleaning, the 6.30 calibrations are performed in house.
Everyone has omitted a lam scan or two ;>)
We do UT work to several codes as well as numerous customer specifications. Several customers do have mock-up welds with reflectors which are very handy. I have looked into some of the kits of welds containing defects and believe they would be valuable, but they are pricey.
Doug, I only skimmed over the article. I'll look at it a little closer before commenting. I too am guilty of violating the warmer than ambient temp rule, but when you have a shop full of welders to keep up with, there are many times it leaves you with no choice. By the time it is cooled to ambient, most of the time, it's already loaded on the trailer. :(
Gotta run now, they just called me to look at 3 full pen column base plates and 3 more 20ft tapered beams with the bottom flange replaced with a plate, full pen for it's entire length. It may be a while before I can sit down and read that article.
Later,
John Wright
Hi guys (& thcqci)
RE:
1) A large reinforcing fillet weld may make a groove weld UT uninspectable and there are many more combonations that are not UT inspectable. ie reinforcing fillet weld around a tubular T-Y-K Weld Joint after completion with a Negative "G" distance.
If your joint or joint combonations are not listed in D1.1 200x table 6.7 etc. you need a specially qualified UT procedure. (ie Longitudional Transducer on top of T Joint, We all do it)
Only the UT NDT Level III can write and approve these. Procedure development and approval is out of the ASNT SNT description of functions for NDT Level II. However, only UT Levels II & I may perform this work. A NDT Level III must be qualified as a UT Level II and must have taken the specific to AWS D1.1 practical test to do Weld UT.
2) UT Inspection temperature limits are a function of the thermal limits of the couplant See AWS D1.1, 6.26.4 for approved couplant types and mixes. Other than this requires Level III approval and calibration adjustments if needed. ie couplants easily have 4-8dB variations, compare that to the acceptance criteria dB ranges.
If you have not completed the AWS Specific Weld UT Examination Test you are not certified to do this type of ultrasonic test.
A series of check boxes for calibrations on the bottom of the UT Test form would serve to document calibration testings.
Calibration testing of the TEST System: Instrument + Cable + Transducer + Wedge is very time consuming 5-6 days per year are required with minimum UT Equipment and no Failures, Replacements, or Swaps for each UT instrument.
Longitutional base metal scans are important and most always forgotten. They should be listed on the UT Report.
The biggest weld ut audit equipment failure is due to air bubbles under the wedge. Use a good silicone grease once a year and forget about it. To Test look into the wedge for silver bubbles (correct if needed) and at the appropriate gain (+20dB) Wipe the couplant off of the wedge face and observe the ring down times in accordance with AWS D1.1 6.30.3.
Air bubbles result in too much gain, noise and to little defect indication reflections.
I hope this help some of us who do try real hard to do this really right.
It's a nasty job and some one has to do it......
More Later;
GESmith,
ACCP NDT level II-UT, AWS D1.1 qualified
ASNT Professional NDT Level III
Why don't you redo your wedge before every job? It only take a few minutes. I posted below that a lam check needs to be done before welding even starts. I have seen laminations in pipe that was declared lamination free by the pipe manufacturer.
Imagine working offshore on a pipelay vessel that costs a quarter of a million a day to operate (a cheap barge) and a lamination is found and it takes 6 hours to back up and cut the joint out. That is $62,500 for something that could have been avoided.
Do a lam check before you inspect any weld and if you find a lamination tell the customer that you can't examine the weld 100%. If the length of the lamination exceeds the length of a rejectable defect the weld needs to be rejected and cut out. You can't repair the weld and still have a lamination there, you need to have the pipe or plate cut back.
Just some helpful info.
You will be astonished about what we do working on pipe laybarges using AUT. After the last welding stall the pipe travels to the AUT station. The weld and pipe are cooled with water maybe less than a minute after it has been welded on. The temperature of the pipe does not really affect UT. What will cause problems is the wedge material getting warmer. If you can keep your wedge at a constant temp then the steel you inspect can be hot enough for you not to be able to keep your hand on it.
You can actually put a garden hose on a weld that was just made and it won't make it crack. The water never touches the metal because the water boils off until the metal reaches the temp that water does not boil.
Certain welds types are prone to cracking and you must inspect them again 48 hours after the initial inspection.
Sounds crazy but it works.
Oh yeah I forgot to add, I have never failed to to a lam check. You must do them or the weld needs to be cut out. If no lam check was done before the weld was made it is an automatic cut out. I will refuse to inspect it. You can't do a lam check over what has been welded even if they grind it flush for you. So don't let people push you around with that argument.
On a majority of jobs I have been on we have had to calibrate before the weld is inspected and after. You Cal in, inspect the weld and then Cal out. If you change anything between the Cal in or out you must re-inspect the weld after you Cal in again.
Doug,
I apologize, I still haven't looked at that article. Those 3 tapered beams ended up being a total of 32 and boy am I using up the couplant around here. They are placing 4 and 5 to each fitter's table and of course they are finishing up about the same time, so I just keep traveling from table to table. I'm hoping to catch up later this week before the next wave of full pen columns come through. I've also got to get into my office and get these reports caught up. I'm taking good notes and fortunatley there have been very few indication worth noting or rejecting.
John Wright
I have actually enjoyed this thread as good comments have been made.
My only suggestion would be for you to consider taking a hands-on UT flaw detection and characterization course and immediately take the API QUTE test afterwards. This course will improve your skills and prepare you for a somewhat challenging examination. The results will possibly yield an additional certification that in my opinion will separates the men from the boys. As for the other courses specific to fundamentals, consider reading the general dynamics books and save your employer the expense and to justify my more practical course of action.
Keep in mind this is just my opinion and it is based on my personal needs as I’m a self-employed inspector. The value of this certification would be based on your local clients needs and requirements. Regardless, I have no doubt that this certification will increase both your value and volatility as a UT shear wave examiner.
Course link:
http://www.nde.com/API%20QUTE%20Course%20Outline.pdf
Examination Link:
http://api-ep.api.org/quality/index.cfm?bitmask=002001003010000000
If you have any questions or require and additional information, please don’t hesitate to drop me a line.
D Payne
ASNT Level III, AWS-CWI,
API 510/570/653/QUTE
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