Knowledge

Improving Small Diameter Pipe Weld Inspections with Encoded Phased Array Webinar

This webinar provides a brief overview of the physics of phased array ultrasound and demonstrates the benefits of this innovative technology for the inspection of small diameter piping in new construction or during the maintenance of boilers, heaters, cracking furnaces and other piping systems. Although radiography has been the inspection tool of choice for many years for these inspections, this 45-minute presentation discusses the many advantages of phased array ultrasound: mainly faster and safer inspections without shutting down the work area around the inspection and providing additional flaw measurement capability over radiography. The latest advances in portable semi-automated ultrasonic systems along with low-profile scanners, probes and wedges optimized for small diameter piping are important factors that have contributed to the acceptance of phased array in the petrochemical and related industries.
Q&A from Webinar below.

Question: Would this be appropriate for industrial use if it were only used approximately 6-12 times per year. My concern is that limited usage would not allow for familiarization with the equipment.

Maybe, it depends on several variables. As shown a cost savings and other benefits can be had even with a small amount of welds. The decision to buy equipment or have an outside service provider already trained is a big question for many of our potential customers. Either one can make sense depending on the individual variables. It is important that inspectors keep up on the operation of the equipment along with any required certifications.

Question: Larger diameter pipe inspections would require different wedges and probes?

Yes, you can view our entire line of Industrial scanners on our website at http://www.olympus-ims.com/en/scanners

Question: using sectorial scan, how do you know what the probability of detection is on the weldboundary for planar defects

There are a variety of simulation software programs that can help predict these types of things but often n a mock up of the weld with representational artificial defects or a sampling of real world known samples is the best approach to develop a quantified test.

Question: is there a technique or scanner for socket weld inspections on small diameter pipe?

These types of inspections can vary in geometry greatly; suitability of off the shelf solutions should be confirmed with a representative

Question: What about transverse cracks?

Transverse crack scan requirements are often met with a quick conventional shear wave test that is documented on the report.

Question: How to quantitatively evaluate the location/size error for different diameters considering elevation direction fixed focusing?

The passive mechanical focusing results in a wide beam that is less wide throughout the inspection range compared to flat array, but does not have the same affect as the active focusing. A Proper calibration and test setup ensures results through the entire range

Question: Can you comment on single sided access and does this meet 100% coverage requirements?

You should confirm your specific code requirements but yes, many codes do allow for this. It may be part of the performance demonstration process to demonstrate capability from one side. Phased array is generally much better than conventional methods.

Question: Calibration standards - do you offer ability to purchase cal standards through Olympus? If not, where can they be obtained?

We only offer a handful of basic calibration blocks but many manufacturers offer them. You can do a web search or contact your regional representative for some options.

Question: Is the equipment suitable for HDPE weld inspections?

Maybe, we actually offer a different solution that can be seen on our website, HDPE often has unique considerations. http://www.olympus-ims.com/en/applications/ultrasonic-tofd-butt-fusion/

Question: What NDT qualification you need to do a PA inspection?

That can vary greatly on whether it is code based and what code. ASNT SNT-TC1A recently published some guidelines and there are various other specific code reference. You should confirm to the inspection n code you are working to.

Question: You mentioned in Example 3, austenitic steel inspection. How you are testing that material with Phased Array?

I have no results with larger thickness. With Cobra I have tried 5mm pipe and it was also very difficult. A lot of material noises. Austenitic can vary greatly from one to another and should be tested. Often refracted longitudinal waves can offer some benefit. Depending on the material it may be attenuative, noisy, scattering etc., so it is hard to generalize.

Question: What is your procedure for calibrating with curved wedges?

We have seen many approaches, from using curved calibration samples or using flat wedges and SDH and then attaching curved wedge and adjusting pn piping samples and notches. This is up the procedure writer and LIII.

Question: How to calibrate wedge delay with curved wedge?

We have seen many approaches, from using curved calibration samples or using flat wedges and SDH and then attaching curved wedge and adjusting pn piping samples and notches. This is up the procedure writer and LIII. If the wedge is already in a suitable tolerance you may decide a wedge delay is unnecessary.

Question: What MHZ PA probe do you suggest for WT between 1/2"-1 1/2"

There are many variables to that question (material, minimum flaw size, etc.) In general 5 MHz may be a good place to start.

Question: For large diameter welds with counter bores. How do you assure you get sound in the upper portion of the weld, since bouncing off the counter bore won't let you get sound where you intend on the bounce.

We would need more info to provide an exact answer. Often with the Multigroup capability and/or multiple probe positions a relatively easy scan plan can be designed.

Question: How you make characterization with only Phased Array UT?

Characterization is usually made by a combination of location of flaw and A-scan and S-scan characteristics. The same flaw information we know from conventional is all in the A-scans but know we have the images, digital readings, weld overlays and merges at our disposal.

Question: Is it possible to use Cobra for PA corrosion mapping on boiler tubes?

The cobra is designed for weld scanning only, so maybe for weld root corrosion/erosion. We have other solutions for wall corrosion mapping utilizing the chain scanner. http://www.olympus-ims.com/en/corrosion-solutions/

Question: You showed inspection data from Austenitic tubes, what frequency are you operating at for this and what limitations to test are there?

In general austenitic can be scattering, noisy, attenuative, etc. Lower frequencies of 1 and 2 MHz are not uncommon. Also the use of refracted longitudinal waves over shear may be necessary.

Question: Is Phased Array a good system to inspect the wind towers welding?

We have had a lot of success here with phased array, but also just Tofd and conventional. We have several scanning systems and approached for this inspection and lots of expertise.http://www.olympus-ims.com/en/weld-solutions/

Question: What is the best solution for 8mm austenitic steel weld? 2.25 MHz, A10 probe didn't bring any results... I wasn't able to see any defects (real and artificial flaws visible on X-ray)

There are too many variables for an exact answer. You may want to try refracted longitudinal waves as an option to start.

Question: About wind tower welding - what PA solution do you propose? For PA I see a problem because of large thickness (up to 70 mm).

That thickness in general is not a big issue. I would typically suggest Tofd and conventional (with creeping wave as necessary for top surface) or Phased array and Tofd. Which one is suitable comes down to the inspection specifics but usually either can be employed relatively simply.