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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.