CWB Weld Journal - Spring 2022
Basic factors affecting the accuracy of ultrasonic weld testing
Non-destructive testing uses the application of physics to reveal the invisible. Tiny cracks which cannot be seen by the eye suddenly pop out under UV light, steel is turned translucent when imaged using radiation, and those trained in the dark arts of eddy currents cast spells and throw chicken bones. At the basis of them all are well-understood processes and equations with practical limitations and variations.
This article presents a summary of the variables affecting the accuracy of conventional ultrasonic techniques, although they can also be applied to phased array. A brief understanding of variables is important to appreciate the practical effects they can have on real-life inspections and for managing expectations.
CWB Weld Journal - Fall 2019
Phased Array and Changes to Ultrasonic Testing of Structural Welds in Canada
Most inspection codes worldwide have made strides to introduce newer technologies in the past few decades. Phased array ultrasonic testing (PAUT) is one major advancement which is now common practice. This article attempts to distill the technology down to a few main talking points, highlight the introduction of PAUT into CSA W59-18, and discuss the implications on inspection results.
AWS Welding Journal - March 2018
distance-amplitude techniques and their adaptation to structural steel weld inspection
Ultrasonic inspection techniques for structural steel welds in North America were developed in the late 1960's. Since then, technology has exploded and a vast array of UT applications has spread across the industry. Yet we continue to use the old "2 dB per inch" technique, complete with bulky probes and angle-specific inspection procedures.
The CSA W59 committee put a great deal of time and effort into adapting the tried and true acceptance levels to modern UT techniques.
This is "the white paper" for upcoming changes to W59, including adoption of the use of DAC/TCG and a variety of different probe sizes and frequencies, not to mention phased array.
Cinde Journal Vol. 38 NO. 3 - May/June 2017
Structural UT: Variables affecting attenuation and review of the 2 db per inch model
This article serves as the precursor to a presentation made at the NDT in Canada 2017 Conference. It provides the mathematical models and experimental data to rationalize a paradigm shift away from the linear attenuation model used for many years in North American structural UT codes to a time corrected gain (TCG) for sensitivity calibration. Ever wonder what would happen if you used a 5MHz, 1/2" diameter probe with AWS D1.1 or CSA W59? No? Never mind then.
ASNT Materials Evaluation Vol. 74 No. 9 - September 2016
Ultrasonic Testing of Structural Welds: Improving on the 6 dB Drop Technique for Determination of Discontinuity Length
This article begins with a painfully long title, but then it gets better. Here's the executive summary:
The indication peak is rarely just 6 dB louder than the ends of a real weld flaw... yet this is what is classically taught as the golden rule. If you keep doing it this way, you're going to undersize the length. The welder may fix only what you marked, potentially leaving two "new" (but not new) indications, one on each end of the original flaw. The welder will end up hating you.
CINDE Journal Vol. 37 No. 3 - May/June 2016
Gating Techniques for Ultrasonic Thickness Testing Using Flaw Detectors
An entertaining romp through the ins and outs of setting up a flaw detector to take thickness measurements. Thickness gauges like the Olympus 38DL Plus are great, but oftentimes you find yourself armed with a full fledged flaw detector like an Epoch 600. It's important to know your gate modes and the repercussions of differences in measurement and calibration points.
This was my first published article, which is why it's written in crayon.