Ultrasonic Testing. New Generation of Non-Destructive Inspection Devices

Ultrasonic testing (UT) with gauges and transducers is one of the most important non-destructive testing (NDT) techniques available today, and it has multiple powerful applications across various industries. Just recently, Tauro Tech’s engineers have finished an important project in this field, designing and producing a new ultrasonic thickness gauge device that implements IoT and other tech innovations to achieve a new level of industrial inspection effectiveness. 

Today, in the era of digital transformation, we have unprecedented opportunities to empower already advanced techniques, such as ultrasonic testing, with latest technological solutions and automation capabilities, producing a new generation of devices able to perform processes with greater efficiency. 

What is Ultrasonic Testing? 

Ultrasonic testing is a non-destructive testing technology that is based on the propagation of high-frequency sound waves in the material or object tested in order to detect internal flaws or gather information about the state and character of the materials. Normally, UT is conducted by transmitting ultrasonic pulse-waves (frequencies typically ranging from  0.1-15 MHz up to 50 MHz) with ultrasonic transducers or thickness gauges.

• What is an ultrasonic transducer? 

An ultrasonic transducer is basically any device that is able to convert electrical energy into high-frequency sound waves, as well as detecting sound waves with ultrasonic sensors and converting it back to electrical energy. There are three types of ultrasonic transducers: 

• Transmitters (they convert electrical signals into ultrasound),
• Receivers (they convert ultrasound into electrical signals),
• Transceivers (they can do both). 

Today typical ultrasonic transducers are small hand-held devices that can come in various forms, shapes and with different sensors depending on the specific type of ultrasonic testing they are used for. 

• What is an ultrasonic thickness gauge? 

Ultrasonic thickness gauge is a type of ultrasonic testing device that works on the same principle and is used to check material properties, for all kinds of thickness measurements primarily. Various types of ultrasonic thickness gauges are used to test the thickness and other parameters of common materials such as metal, cement, glass, ceramics, etc. 

Applications of Ultrasonic Testing 

Ultrasonic testing is commonly applied across industries for two types of measurements: 

1. Detection of fractures, cracks and other kinds of defects in objects.
2. Measuring the thickness of the material. 

Today, UT is the primary way of testing industrial installations and facilities made from materials with dense structures such as metals and alloys. But UT can also be used to test multiple other materials, including plastics, composites, ceramics, concrete, wood, and others. 

Ultrasonic transducers can detect a wide variety of structural integrity problems with an object or material, including voids, cracks, disbounds, etc. Here are some of the most typical applications of ultrasonic transducers when it comes to specific products: 

• Railroad rails, 
• Metal pipelines and tanks,
• Steel beams,
• Structural welds,
• Aircrafts (frames and engines)
• Automobiles and heavy machinery,
• Ship hulls.

Ultrasonic gauges are typically used to measure the wall thickness in metal pipes and tanks, but have multiple other applications in areas where a precise measurement of a wall thickness needs to be done without the access inside or emptying a pipe/tank. To name a few examples: 

• Precision machines or cast parts,
• Molded plastic containers,
• Small diameter medical tubing,
• Rubber tires and conveyor belts,
• Contact lenses. 

Pros and Cons of Ultrasonic Testing 

As you can see, ultrasonic testing is quite a unique technology that has a wide range of extremely useful applications across industries. Naturally, like any solution, it has its set of strengths and weaknesses. 

Pros of UT

1. High sensitivity. UT allows to detect even micro flaws and cracks in objects/materials. 

2. Great penetration power. Thanks to high penetration of UT, even flaws deep in the part can be successfully detected. 

3. High precision. Ultrasonic testing is more accurate than most other nondestructive testing methods.

4. Safety. UT is also completely safe both for human personnel and equipment or materials, which makes it easy to use UT for inspection without the need to stop the production or operations of the facility. 

5. Quick results. Another strength of UT is the fact that testing results are available immediately.

6. Portable and automated. Ultrasonic testing is also a very portable and easy to automate technology, which is an important factor for many large-scale projects. 

Cons of UT 

UT as a technology also has a number of weaknesses, and when designing a new IoT thickness gauge device we at Tauro Technologies were aiming at eliminating or minimizing them as much as possible. 

1. Trained operator is required to set up and conduct the inspection procedure. 

2. Inspection of complex, irregular or rough objects can be challenging. 

3. UT testing devices must be separately calibrated to every material measured. 

4. Surfaces need to be prepared for inspection by cleaning and removing some types of coating and paint. 

5. Complex measurement projects typically require multiple setups. 

6. Ultrasonic testing equipment normally is more expensive compared to mechanical measurement devices.

Ultrasonic Non-Destructive Testing Process

When it comes to the actual UT inspection, it requires an ultrasonic transducer equipped with a set of sensors necessary to conduct the testing, and a display device. The transducer is then connected to the diagnostic machine and applied to the tested object/material. The surface of the tested object should be separated from the transducer with a couplant such as oil or water. 

During the operational stage, ultrasonic waves penetrate through the tested object and reflect back when they hit the boundary with another medium. Being recorded and interpreted by the measurement devices, this data allows qualified technicians to identify flaws and cracks in objects, as well as to measure their thickness. 

Ultrasonic IoT Thickness Gauge Device by Tauro Technologies 

As it should be clear from the above, one of the most crucial challenges about the non-destructive ultrasonic testing process the way it is typically conducted today is that it requires a trained technician walking around the facility and manually measuring the thickness of pipe walls and other installations. Needless to say, this makes ultrasonic testing a tedious process, requiring a lot of time and manual labour. 

And this is the problem we at Tauro Technologies wanted to solve by developing a new battery-powered ultrasonic IoT thickness gauge device that uses off-the-shelf ultrasonic transducers such as Yushi PT-8.

Our UT device can be permanently installed in predefined locations on the manufacturing floor. The IoT sensor will be activated during fixed time intervals that can be set up by the user to perform thickness measurements using echo-to-echo detection technique. 

• What is echo-to-echo?

There are two primary methods used for the ultrasonic non-destructive testing process: echo-to-echo and pulse-echo.

1. Pulse-echo

In the pulse-echo technique, an ultrasound wave is excited and detected by two transducers (transmitter and receiver) that are glued to polished opposite sides of a sample. When a radiofrequency (RF) signal is applied to the transmitter, it generates an ultrasound pulse spreading across the sample and producing an RF pulse in return, which then propagates back and forth creating additional RF pulses at the receiver. The sound velocity and attenuation are then used by the device to obtain the material measurement results. 

2. Echo-to-echo

The echo-to-echo technique uses gates set around two consecutive backwall echoes and measures the difference between them, which allows to extract the coating thickness from the measurement results and return just the part thickness. 

As the coating can add a significant error to the measurement results, echo-to-echo is the method that supports non-destructive ultrasonic testing with highest level of accuracy. 

Once the measurements are collected, the IoT thickness gauge developed by Tauro Technologies automatically performs all the necessary calculations to come up with the measurement results based on the selected material type. The measurement report is then being transferred to a cloud-based server where all this data can be safely stored, accessed and visualized if needed. 

Summary 

Thanks to its multiple strengths, today UT is a truly indispensable way to conduct non-destructive testing of objects and materials. And with new-generation UT devices, such as the IoT thickness gauge by Tauro Technologies, ultrasonic testing gets more accessible, reliable and cost-effective than ever before.

Interested to know more? Get in touch with us for details.