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What Is Non-Destructive Testing (NDT)? A Complete Guide

Apr 7, 2023 ·

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Non-destructive testing (NDT) is a set of testing and analysis processes that evaluate the quality and structural integrity of a manufactured product. Factories and manufacturing plants commonly use NDT. However, some unexpected fields, such as medicine, have also found a use for it.

NDT technician skills are of value to various industries because they save them time and money and determine safety with a high level of accuracy.

Want to learn more about NDT? In this blog post, we’ll define non-destructive testing in further detail and share how you can train to pursue a career in NDT.1

What Is Non-Destructive Testing?

Non-destructive testing (NDT) is sometimes referred to as non-destructive evaluation (NDE), non-destructive examination (NDE) or non-destructive inspection (NDI).

Each of these titles involves the same process of inspecting the integrity of a product without destroying it. In other words, as long as the product meets set specifications, it should still be usable once the testing is complete.

Many industries prefer NDT to destructive testing (DT), where technicians analyze a material by pushing it to failure. Because destructive testing destroys products, companies must allocate resources to create samples for testing. On the contrary, if a product passes NDT, it can move through the supply chain.

Not only does this save companies time and money, but it also creates a more accurate testing process and improves customer satisfaction.

So, how do you test a product's strength without pushing it to its breaking point? NDT relies on technology and science to do so.

Non-Destructive Testing Methods

While there are countless ways to carry out NDT inspection, the five most common types of non-destructive testing include eddy current, visual penetrant, magnetic particle, radiography and ultrasound testing.

MIAT College of Technology teaches each method in its NDT technician program in Houston, Texas. Read more about these NDT techniques below.1

Eddy Current Testing

Eddy current is a type of electromagnetic testing (ET). This type of NDT introduces an electric current or magnetic field to a workpiece.

In this method, an alternating current coil is used to create an electromagnetic field. When the magnetic field forms, so do eddy currents. The eddy currents then counter the magnetic field by forming a second one.

This process allows NDT technicians to examine the currents' behavior closely. If the currents present abnormally over a certain part of the workpiece, there are likely discontinuities or flaws, such as cracks.

Visual Penetrant Testing

Also known as liquid penetrant testing, this method of NDT identifies impurities, such as cracks, in the surface of a part. Visual penetrant NDT is typically used on non-ferrous metals.

This type of NDT involves spraying a dyed liquid penetrant on top of the base metal and leaving it to sit according to the product's instructions. As the liquid sits on the workpiece, it will sink into any present cracks.

After some time, the NDT technician wipes the penetrant away and adds a thin layer of a developer. The developer pulls penetrant that may have seeped into the metal’s impurities back to the surface for the NDT to evaluate.

Magnetic Particle Testing

Magnetic particle NDT identifies impurities on or just below the surface of a workpiece by creating a magnetic field using a permanent magnet or electromagnet. An electromagnet requires a current.

Both methods create magnetic flux lines that alter in the presence of impurities. Unfortunately, this isn’t visible to the human eye. Therefore, NDT technicians add colored magnetic particles in powder or liquid form. If flaws are present, the particles will gravitate toward them for the NDT technician to examine.

Radiography Testing

In radiography NDT, a radiographic film is placed on the opposite side of the metal part. The technician applies a radiation source, such as an X-ray to the part. It passes through both the test object and film.

If there are discontinuities in the metal part, the radiation will darken the film in this area.

Ultrasound Testing

In ultrasound testing, a transducer transmits through a test piece via a probe. The sound wave travels through the material. If the sound wave hits a reflector or flaw within the material, it will return to the transducer as an electric impulse.

These electric impulses are typically displayed on a screen for the NDT technician to evaluate.

Where Is Non-Destructive Testing Used?

While NDT can be used in a variety of environments, the Bureau of Labor Statistics (BLS) lists the following industries as the most common:

  • Architectural, engineering and related services
  • Machinery manufacturing
  • Transportation equipment manufacturing
  • Scientific research and development services
  • Computer and electronic product manufacturing

NDT technicians may also be employed in the mining, aerospace, automotive, power generation, or oil and gas industries.

Real-World Non-Destructive Testing Examples

To communicate how significant NDT inspection is to our every day, we'll specify a few ways it is used in the real world. Non-destructive testing examples include:

  • Testing manufactured medical devices to ensure they're durable and functional
  • Testing pipelines that carry hazardous materials like oil and nuclear elements
  • Testing welds for the transportation, automotive and infrastructure industries
  • Evaluating the condition and lifespan of equipment used in manufacturing, oil refineries and more

NDT technicians have a job that matters. They can prevent accidents, maintain important machines and structures, guarantee product quality and more.

If this sounds like shoes you'd like to fill, keep reading to learn about the career outlook for an NDT tech.

NDT Demand and Salary Outlook

According to the BLS, total NDT technician employment is expected to exceed 78,000 by 2031, suggesting there is a demand for NDT technical skills.70

A career in NDT could be a good career path for the right candidates. Per the BLS, the median annual salary for NDT technicians in the United States was $65,520 in May 2022.62 This means half of NDT technicians earned more and half earned less. Keep in mind salary depends on several factors, including experience, employer, demand and cost of living in the area.

Before pursuing careers in this industry, most aspiring technicians attend a trade school to learn the complex processes associated with non-destructive testing. MIAT’s NDT program starts from the ground up, providing students with a base of knowledge they can build upon.1

Potential NDT Career Paths

There are multiple career paths NDT technicians can pursue. However, most begin in entry-level positions in one of the industries mentioned above. Common entry-level positions include NDT technicians, quality control technicians and inspectors.

Most of our grads start out working as entry-level technicians or in other entry-level roles. As with any industry, over time, you may be able to advance in your career with hard work.77 Experienced NDT technicians may advance into positions such as industrial radiographers, NDT/NDE technician level I, RT assistants or QC/QA inspector assistants.

Non-Destructive Testing Schooling

Aspiring NDT technicians can prepare for careers in this field by completing a training program. NDT is a highly complex field that could be difficult to break into without a formal education. Upon completing a training program, graduates have a foundation of knowledge to build on.

MIAT's nine-month training program provides students with over 800 hours of hands-on training in a lab. Throughout those nine months, students take the following courses:

  • Visual Theory/Application I and II
  • Penetrant Theory/Application I and II
  • Eddy Current Theory/Application I and II
  • Magnetic Particle Theory/Application I and II
  • Ultrasound Theory/Application I and II
  • Radiography Theory I

These courses prepare them to examine properties of a material, component, structure or system and ensure it’s free of defects.

Non-Destructive Testing FAQ

What Are the Different NDT Techniques?

NDT employs several techniques, and each one serves a unique purpose. The type of technique a technician should use depends on the industry or company's needs. MIAT teaches the primary techniques: eddy current, visual penetrant, magnetic particle, radiography, and ultrasound.

How Long Does It Take to Get NDT Certified?

To become certified, aspiring NDT technicians require formal training and on-the-job hours. Upon completing a training program and securing employment, your employer can lead you through certification if needed.

What Certification Is Best for NDT?

The American Society for Non-destructive Testing (ASNT) has distinguishable certifications that are internationally recognized. Becoming certified typically requires formal training as well as on-the-job experience. ANST offers multiple certifications. An employer can help prepare you for the right one.

Train for Non-Destructive Testing at MIAT

NDT technicians are responsible for ensuring the integrity of materials, structures and components crucial to various industries and our day-to-day activities.

Taking on this responsibility is a lot of pressure but can be very exciting for anyone who is detail oriented, enjoys being challenged and has a passion for science and technology. Are you up to the challenge?

If so, request info to learn more about MIAT’s NDT Technician training program today.

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1) UTI and MIAT are educational institutions and cannot guarantee employment or salary.

2) For program outcome information and other disclosures, visit for UTI and for MIAT.

62) The Non-Destructive Testing (NDT) Program prepares graduates for entry-level positions using the provided training, primarily as non-destructive testing technicians. Estimated annual salary is for Engineering Technologists and Technicians, Except Drafters, All Other as published in the U.S. Bureau of Labor Statistics’ May 2022 Occupational Employment and Wages. Entry-level salaries are lower for graduates. UTI and MIAT are educational institutions and cannot guarantee employment or salary. Graduates’ achievements may vary. Individual circumstances and wages depend on economic factors, personal credentials, work experience, industry certifications, the location of the employer, and their compensation programs. Some graduates get jobs within their field of study in positions other than as non-destructive testing technicians, such as quality control technicians and inspectors. Salary information for the Commonwealth of Massachusetts is available at Salary information for North Carolina: The U.S. Department of Labor estimates the hourly median wage for skilled non-destructive testing technicians in North Carolina is $33.29 (Bureau of Labor Statistics, U.S. Department of Labor, May 2022 Occupational Employment and Wages, Engineering Technologists and Technicians, Except Drafters, All Other). The Bureau of Labor Statistics does not publish entry-level salary data. However, the 25th and 10th percentile of hourly earnings in North Carolina are $24.51 and $18.40, respectively.

70) For Engineering Technologists and Technicians, Except Drafters, All Other, the U.S. Bureau of Labor Statistics projects an annual average of 7,800 job openings between 2021 and 2031. Job openings include openings due to net employment changes and net replacements. See Table 1.10 Occupational separations and openings, projected 2021-31, U.S. Bureau of Labor Statistics,, viewed October 13, 2022. UTI and MIAT are educational institutions and cannot guarantee employment or salary.

77) UTI is an educational institution and cannot guarantee employment or salary. UTI prepares graduates for entry-level careers using the provided training. UTI graduates’ achievements may vary. Some UTI graduates get jobs within their field of study in positions other than those listed.

Universal Technical Institute of Illinois, Inc. is approved by the Division of Private Business and Vocational Schools of the Illinois Board of Higher Education.


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