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What’s the Advantage and Limitation of Ultrasonic Testing?

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Ultrasonic testing, or UT as it is often called, has many uses in the world of manufacturing and quality control. It involves the use of ultrasound to detect defects in products such as metal components and other structures, even when they are hidden under paint or another surface layer.

Ultrasonic testing can be used to find ut flaws that may have been overlooked with more traditional quality control techniques, improving product safety and reliability while reducing costs over time.

However, there are several limitations to ultrasonic testing that should be kept in mind when considering this technology as part of your QA process. Continue reading below to learn more about the advantages and limitations of ultrasonic testing.



I. What is Ultrasonic Testing? 



Ultrasonic Flaw Detector UE0040


Ultrasonic testing, also known as UT, or ultrasonic examination, uses high-frequency sound waves to inspect an object’s surface and detect flaws.

UT was originally developed in the 1940s to determine the thickness of welded seams in aircraft carriers and battleships, but since then, it has evolved into an indispensable tool that quality control technicians use every day to ensure consumer safety and monitor manufacturing quality.

It works by emitting high-frequency sounds and detecting how they bounce off the subject under inspection—subtly different sounds will mean there are surface defects on the object being tested.

The testing involves placing a transducer over a material and transmitting sound waves into it. When these waves hit an imperfection in a structure, they will reflect back to their source at an altered frequency; that’s how you can measure flaws in real-time with no contact.

An expert ultrasonics technician may be able to pinpoint problems that traditional methods miss—that’s why ultrasonic testing is so commonly used for detecting cracks in structures like aircraft wings or bridges.

The test results in images are called sonograms. Like any type of nondestructive testing (NDT), ultrasonics is a valuable technique because it allows engineers to evaluate a product without causing physical damage.


➤ Related Article: Everything you Want to Know About Ultrasonic Testing



II. Why is Ultrasonic Testing Important?


Ultrasonic testing (UT) is an important part of many manufacturing processes. It is used to detect defects or check for flaws in an object’s construction.

Ultrasonic testing gives manufacturers better insight into how their products age over time; if a manufacturer can find out why some products fail faster than others after shipping—whether it’s environmental factors or incorrect manufacturing processes—they can reduce those risks for future shipments.

This can help a manufacturer identify issues that may cause problems in later stages and be addressed before they affect quality or functionality.



III. How Ultrasonic Testing Works?


The most common type of ultrasonic testing works by producing a sound that’s above what humans can hear. It then analyzes how long it takes for that sound to bounce back after colliding with something like a surface or object.

The time taken for reflection, along with properties like amplitude, is used to determine information about whatever is being tested. These test results can be used to evaluate things like weld quality on car doors or weld integrity on bridges.

They also allow technicians to detect problems early before they become major issues. Small variations in sound waves could indicate cracks or other structural defects. In some cases, when combined with other testing methods, it allows engineers to test components during operation without stopping any processes or interrupting anything happening at all.



IV. What is the Basic Principle of Ultrasonic Testing?


Often referred to as ultrasonic inspection, ultrasonic testing uses sound waves to examine a material’s internal and external structure. The basic principle underlying ultrasonic testing is that materials have different acoustic properties.

A pulse of high-frequency sound is produced in an emitter or piezoelectric transducer, transmitted into a receiving transducer and recorded by a receiver or strain gauge. Sound travels at approximately 3.1 miles per second in the air (or 5 miles per second through water). The speed of sound varies depending on temperature, however.


V. What are Advantages and Disadvantages of Ultrasonic Testing?


Here are the advantages and limitations of ultrasonic testing are so that you can make an informed decision about using this technology during your production line inspections.


Advantages Of Ultrasonic Testing

  • Portability

The equipment can be portable. It is also one of several methods that can be used to detect flaws in metal, plastic, wood, concrete, etc.

  • It’s reasonably simple to use

The most common types of ultrasonic testing equipment are sound source generators and electronic receivers.

Both must have a specific frequency for optimal results—typically 40 kilohertz for ferrous materials (metal), 50 kilohertz for nonferrous material (plastic or wood), and 20 kilohertz for concrete structures or structures made from composite metals.

A typical test may last only two or three minutes, but tests with more sensitive equipment may take longer.

  • Little to no damage

An ultrasonic inspection does not damage items being tested because it uses sound waves at frequencies too high to cause pain when humans hear them.

  • Lower energy consumption

Energy consumption is low compared with other physical non-destructive testing processes such as magnetic particle inspection and radiography, which use ionizing radiation to evaluate objects (although they do not involve sound waves).

Moreover, ultrasound is unaffected by magnetism and radioactivity, so it can be used on these types of objects without damaging them.

  • Safe for testers

The devices that create and receive ultrasonic signals are designed to protect against possible harm caused by exposure to loud noises. This can help prevent temporary hearing loss caused by continuous loud sounds or permanent hearing loss caused by repeated exposure over time.


Disadvantages Of Ultrasonic Testing

  • Cost

The testing equipment is expensive. Unless you can afford to own a device, you have to pay per test. Per-test fees can run $1,000 or more if you test often or with small parts. You might need special adapters for some parts and surface finishes. Test points tend to be concentrated on larger, more complex parts.

  • Convenience

It’s hard to get a lot of test points when ultrasonic testing involves heating samples in an oven, so it takes time to go back and forth between tests on different surfaces, especially with small samples that heat up quickly.

  • Reliability

This type of testing uses visual methods rather than instruments to see flaws, making them subject to operator interpretation errors.

  • Repeatability

Visual methods are less accurate than destructive analytical techniques like magnetic particle inspection (MPI). They lack sensitivity, too: even top technicians find it hard to diagnose fine cracks at one micron or smaller.

  • Accuracy

An ultrasonic flaw inspection will miss some tiny defects and likely overestimate others, which creates more significant uncertainty in your results.

  • Simplicity

Ultrasonic inspections require experience for anyone outside a lab setting to interpret images correctly—even techs who do nothing but interpret images every day struggle sometimes.


➤ Related Article: Phased Array Ultrasonic Testing: Definition and Working Principle





In conclusion, you should use ultrasonic testing in order to inspect your product. Its advantages are long-term usage, precision, and detection.

Its limitation is if there is noise interference while testing. Therefore, we suggest using ultrasonic testing for inspection of your products on various scales such as pipes or plates. Also, ultrasonic tests can be used not only for plastic pipes but also for metal materials like plates due to their versatility despite different test surfaces.

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