Nondestructive Testing (NDT) Methods, Applications

nondestructive testing

Nondestructive Testing (NDT) is a technical and descriptive term used for materials and components examination in the industry. NDT is also known as Nondestructive Evaluation (NDE) and Nondestructive Inspection (NDI). The process allows materials to be evaluated without destroying or changing their properties. NDT is a Quality Assurance management tool. So, in this article, aspiring people can find a complete guide on various aspects of Nondestructive Testing.

Post Highlights:

  • What is Nondestructive Testing?
  • What is Nondestructive Evaluation?
  • Nondestructive Testing Methods
  • Nondestructive Testing Equipment
  • Nondestructive Testing Standards
  • Nondestructive Testing Schools
  • Nondestructive Testing Courses
  • Nondestructive Testing Certification
  • Nondestructive Testing Benefits
  • Nondestructive Testing Disadvantages
  • Nondestructive Testing Applications
  • Nondestructive Testing Handbook
  • Nondestructive Testing Jobs

What is Nondestructive Testing?

NDT (Nondestructive Testing) is a process of analysis techniques that allow inspectors to collect data about materials such as characteristic differences, welding defects, and discontinuities without damaging their basic properties.

What is Nondestructive Evaluation?
Nondestructive Evaluation (NDE) is a term that is often used interchangeably with Nondestructive Testing (NDT). In NDE, it includes both the testing and evaluation of the results. More candidly, NDE is used to locate defects while also measuring the shape, orientation, size, and other physical characteristics of the defect.

Nondestructive Testing Methods

There are many NDT Testing methods namely refer to the equipment or type of penetrating medium used to perform that test. To examine a wide variety of articles, NDT methods employ sound, electromagnetic radiation, and other signal conversions. The following are current NDT methods or techniques.

Sr. No. NDT Methods
1 Acoustic Emission Testing (AE)
2 Electromagnetic Testing (ET)
3 Guided Wave (GW)
4 Laser Testing (LM)
5 Leak Testing (LT)
6 Liquid Penetrant Testing (PT)
7 Magnetic Flux Leakage (MFL)
8 Magnetic Particle Testing (MT)
9 Neutron Radiographic Testing (NR)
10 Radiographic Testing (RT)
11 Thermal/Infrared Testing (IR)
12 Ultrasonic Testing (UT)
13 Vibration Analysis (VA)
14 Visual Testing (VT)

1. Acoustic Emission Testing (AE)

Acoustic Emission Testing employs a localized external force such as an abrupt mechanical load or pressure change or rapid temperature to the part being tested. As a result, the stress waves, in turn, generate short-lived, high-frequency elastic waves in the form of small material displacements, or plastic deformation. It happens on the part surface that is detected by sensors and has been attached to the part surface. By using multiple sensors, the resulting data can be evaluated to locate discontinuities in the part.

2. Electromagnetic Testing (ET)

Electromagnetic Testing consists of Remote Field Testing, Eddy Current Testing, and Alternating Current Field Measurement (ACFM). The electromagnetic test is used widely and is considered a stand-alone test method rather than an electromagnetic testing technique. All the techniques induct a magnetic field or an electric current into a conductive part. As a result, the effects are recorded and evaluated.

i) Remote Field Testing – Mostly, the test is used to inspect ferromagnetic tubing due to the presence of a strong skin effect found in such tubes.

ii) Eddy Current Testing – The test applies the fact that when an alternating current coil induces an electromagnetic field into a conductive test piece. Consequently, it creates a small current around the magnetic flux field, the same as a magnetic field generated around an electric current.

iii) Alternating Current Field Measurement – It employs an alternating current into the surface of the test piece, that creates a magnetic field.

3. Guided Wave Testing (GW)

Guided Wave Testing is ideal for testing pipes. It uses controlled excitation of one or more ultrasonic waveforms. Further, it travels along the length of the pipe, reflecting changes in the pipe stiffness or cross-sectional area. To introduce the guided wave into the pipe and each transducer/exciter a transducer ring or exciter coil assembly is used.

To drive the transducer ring/exciter and analyze the results the control and analysis software can be installed on a laptop computer. The setup of the transducer ring/exciter specifically is designed for the diameter of the pipe being tested. The system is able to inspect the pipe wall volume over long distances without removing insulation or coatings. The Guided Wave Testing can locate the discontinuities of both ID and OD, but cannot differentiate between them.

4. Laser Testing (LM)

Laser Testing uses lasers to perform the inspections. It includes three techniques namely Holography, Shearography, and Profilometry.

i) Holographic Testing – It uses a laser to detect changes to the surface of a part as it deforms under induced stress. That can be applied as mechanical stress, heat, pressure, or vibrational energy. The laser beam scans across the surface of the part and reflects back to the sensors. As a result, it records the differences in the surface created by that stress.

The test is used to locate and evaluate disbonds, delaminations, cracks, voids, and residual stresses.

ii) Laser Shearography – It applies laser light to the surface of the part being tested. Then, a charge-coupled device (CCD) picks up the image and stores it on a computer. Further, the surface is stressed. It leads to a new image being generated, recorded, and stored. After that, the computer superimposes the two patterns. If voids or disbonds like defects are present, the patterns developed can reveal the defect. In this way, discontinuities as small as a few micrometers in size can be detected.

iii) Laser Profilometry – The method applies miniature optics, a high-speed rotating laser light source, and a computer with high-speed digital signal processing software. It scans the ID surface of a tube in two dimensions. The reflected light is passed through a lens that focuses that light onto a photodetector. And this generates a signal proportional to the spot’s position in its image plane. The technique is suitable to detect pitting, corrosion, erosion, and cracks in pipes and tubes.

5. Leak Testing (LT)

The technique consists of four methods i.e. Bubble, Halogen Diode, Pressure Change, and Mass Spectrometer Testing.

i) Bubble Leak Testing – It relies on the visual detection of a gas (air) leaking from a pressurized system. In a tank of liquid, the small parts can be pressurized and immersed. By spraying a soap solution, the larger vessels can be pressurized and inspected. As a result, the bubbles will form if there is a leak, and also shows the location of the leak.

ii) Halogen Diode Testing – In this, a system is pressurized with a mixture of air and a halogen-based tracer gas. Then, a halogen diode detection unit or sniffer is employed to detect the leaks after a set period of time.

iii) Pressure Change Testing – This is employed on closed systems only. The leak is detected either by pressurizing the system or pulling a vacuum and then monitoring the pressure. Consequently, if there is a loss of pressure or vacuum over a set period of time, it means there is a leak in the system. Also, temperature changes in the system can cause changes in pressure, therefore adjust readings accordingly.

iv) Mass Spectrometer Testing – The method can be performed by pressurizing the test part with helium or a helium/air mixture within a test chamber. Then use a sniffer to survey the surfaces, it sends an air sample back to the spectrometer. Further, the mass spectrometer is used to sample the vacuum chamber and any helium present will be ionized. It then makes very small amounts of helium readily detectable.

6. Liquid Penetrant Testing (PT)

This testing is performed when a very low viscosity (highly fluid) liquid (the penetrant) is applied to the surface of a part. Next, the fluid penetrates into fissures and voids open to the surface. After removing excess penetrant, the trapped-penetrant in those voids will flow back out and create an indication. This testing is performed on magnetic and non-magnetic materials but does not impart good results on porous materials.

The PT Testing has three techniques i.e. Water-washable, Solvent Removable, and Post-emulsifiable.

i) Water-washable – The penetrants here have an emulsifier that allows the penetrant to be removed using a water spray. Mostly, they are applied by dipping the part in a penetrant tank. But by spraying or brushing, penetrants may be applied to large parts. After this, the part is placed on a drainboard for the penetrant dwell time. Further, the excess penetrant is removed using a course water spray at a rinse station; placed in a warm air dryer or in front of a gentle fan. Before the inspection, the part is placed in a dry developer tank and coated with a developer.

ii) Solvent Removable – The penetrants here require a solvent instead of water to remove the excess penetrant. Usually, these penetrants are visible in nature and dyed with a bright red color that will contrast well against a white developer. After spraying or brushing the penetrants on the part, wait until dwell time has expired. Further, clean the part using a cloth dampened with penetrant cleaner. Finally, the part is examined to detect any penetrant bleed-out.

iii) Post-emulsifiable – In these penetrants, there is no emulsifier included in its chemical make-up like others. They are applied to the surface for a prescribed period of time. After expiring the emulsifier dwell time, the part further undergoes the same water wash. Emulsifiers can be hydrophilic (water-based) or lipophilic (oil-based).

7. Magnetic Flux Leakage (MFL)

The NDT method detects anomalies in normal flux patterns. The discontinuities create anomalies in ferrous material saturated by a magnetic field. The inspectors can use this technique for tank floor inspection, piping/tubing inspection, and other applications.

In tubular applications, the inspection head contains drive and sensor coils and a position transducer. All are connected back to the power source by cable and signal processing computer. For inspection, the head is placed around the pipe or tube and the drive coil is energized. As a result, it creates a magnetic field in the part. As the head travels, the variations in the wall thickness will cause a change in the magnetic flux density. The sensor picks it up and sends it back to the computer. The position transducer sends the location of this signal. So, in this way, the area marked can be evaluated.

8. Magnetic Particle Testing (MT)

The method uses one or more magnetic fields to locate surface and near-surface discontinuities in ferromagnetic materials. The MT techniques consist of Heads, Prods, Coils, Yokes, and Central Conductor

i) Heads – Mostly horizontal wet bath machines have both a coil and a set of heads. When an electric current is passed through, it generates a magnetic field. The name “wet bath” is given due it uses mostly fluorescent magnetic particles in a liquid solution. On the right, a typical bench unit is shown. During the test, the part is placed between the heads. The moveable head moves up and holds the part being tested tightly between the heads. Next, a bath solution containing the magnetic particles is applied to the part. Then the current is applied while the particles are flowing over the part. The current flows from head to head and the magnetic field orients 90° to the current. And this makes visible the indications oriented parallel to a line between the heads. This technique is commonly called a “head shot”.

ii) Prods – These units use direct induction. A circular magnetic field is generated around the legs when the current runs through the part. This happens because the magnetic field between the prods is traveling perpendicular to a line drawn between the prods. Further, it can find the indications oriented parallel to a line drawn between the prods.

iii) Coils – Electric coils are used to generate a longitudinal magnetic field. When energized, the current creates a magnetic field around the wires making up the coil so that the resulting flux lines are oriented through the coil as shown at the right. Because of the longitudinal field, indications in parts placed in a coil are oriented transverse to the longitudinal field.

iv) YokesThis is applied in most of the field inspections. During the process, a central core is wrapped with an electric coil. After applying the current, a magnetic field is generated. Further, it extends from the core down through the articulated legs into the part. It is called “longitudinal magnetization”.

v) Central Conductor – While examining things like tubes, pipes, and fittings, a conductive circular is placed between the heads with the part suspended on the bar. Next, the current is applied after the part is wetted down with the bath solution. It travels through the central conductor rather than the part. Then the OD and ID of the part can be inspected. The magnetic field remains perpendicular to the current flow. Thus, the indications running axially down the length of the part can be found.

9. Neutron Radiographic Testing (NR)

This method employs an intense beam of low-energy neutrons as a penetrating medium. Neutrons penetrate most metallic materials and render them transparent. But they are attenuated by most organic materials and result in the materials being seen within the component being inspected.

10. Radiographic Testing (RT)

This technique involves exposing a test object to penetrating radiation. Further, the radiation passes through the object being inspected and a recording medium is placed against the opposite side of that object. For thinner or less dense materials x-radiation and for thicker or denser materials, gamma radiation is generally used. The RT Techniques comprise Computed Tomography, Digital Radiography, Computed Radiography, and Film Radiography.

i) Computed Tomography – This one uses a computer to reconstruct an image of a cross-sectional plane of an object. Nest, an image is developed from multiple views at different viewing angles. In this method, the computer triangulates using every point in the plane as viewed from many different directions.

ii) Digital Radiography – In this method, radiation is digitized that passes through an object directly into a displayed image on a computer monitor. In direct digital imaging, three technologies namely Charge-Coupled Devices (CCDs), Amorphous Silicon, and Complementary Metal Oxide Semiconductors (CMOSs) are used. These images are available for viewing and analysis.

iii) Computed Radiography – This method employs a flexible, reusable, and photo-stimulated phosphor (PSP) plate. It is loaded into a cassette and is exposed similar to traditional film radiography. It is a transitional technology namely between film and direct digital radiography. Then, the cassette is placed in a laser reader and scanned and translated into a digital image. Finally, the image is uploaded to a computer for interpretation.

iv) Film Radiography – This one uses a film made up of thin transparent plastic. It is coated with a fine layer of silver bromide on one or both sides of it. The crystals undergo a reaction when exposed to radiation. As a result, it allows them to convert to black metallic silver when developing. Further, the silver is fixed to the plastic. It becomes a finished radiographic film when dried.

11. Thermal/Infrared Testing (IR)

Thermal/Infrared Testing is also known as infrared thermography. The method is used to measure or map surface temperatures. Infrared radiation is given off by an object after heat flows to, from, or through that object. The majority of infrared radiation is longer in wavelength and can be detected using thermal imaging devices like infrared cameras. For accurate IR testing, the part should be in a direct line of sight with the camera.

12. Ultrasonic Testing (UT)

The method uses the same principle as that of naval SONAR and fish finders. Ultra-high frequency sound is introduced to the object. If the sound hits the very object with a different acoustic impedance, then some of the sounds will reflect back to the sending unit. And it can be presented on a visual display. The most common sound frequencies this technique uses are between 1.0 and 10.0 MHz. The compression (longitudinal) wave and the shear (transverse) wave are common ones used in industrial inspections.

The Ultrasonic Testing techniques consist of Angle Beam, Through Transmission, Straight Beam, Phased Array, Immersion Testing, and Time of Flight Diffraction.

i) Angle Beam – This one uses a transducer that is mounted on an angled wedge. A transducer is designed in such a way that transmits the sound beam into the part at a known angle. The most common angles used in an inspection are 45°, 60°, and 70°. During an inspection, the transducer and wedge combination is moved back and forth towards the weld. It lets the sound beam passes through the full volume of the weld.

ii) Through Transmission – This method uses two transducers for inspections, one on each side of the part. One transducer sends the sound through the part and another receives the sound. Reflectors in the part cause a reduction in the sound amount that reaches the receiver. As a result, the screen presentation shows a signal with a lower amplitude.

iii) Straight Beam – This technique uses longitudinal waves to interrogate the test object. The sound from that reflector will reflect the transducer if the sound hits an internal reflector. It is faster than the sound coming back from the back wall of the part. Further, it imparts screen display (result).

iv) Phased Array – It uses a probe with multiple elements for inspections. They can be activated individually. When each element is activated, the resulting sound beam can be steered. So, the resulting data can be combined to form a visual image. The image represents a slice through the part being inspected.

v) Immersion Testing – In this technique, the part is immersed in a water tank with the water being used as the coupling medium. It allows the sound beam to travel between the part and the transducer. Put the UT machine on a movable platform on the tank side for traveling down the length of the tank. The transducer is swivel-mounted on a waterproof tube at the bottom. Then, both the tube and bridge movement permits the transducer to move on the X-, Y-, and Z-axes. Here, all the travel directions are gear-driven.

Often, the round test parts are mounted on powered rollers. For multiple scans, multiple transducers can be used at the same time.

vi) Time of Flight Diffraction – It uses two transducers placed on opposite sides of a weld with transducers. They are set at a specified distance from each other. One transducer transmits sound waves and another works as a receiver. Here, the transducers are not manipulated back and forth towards the weld like in other beam inspections. During this, two sound waves are generated. One travels along the part surface between the transducers, another down through the weld at an angle. If there is a crack on the part, the sound is diffracted from the crack-tip. After that, it generates a low-strength sound wave that a receiver unit picks up. In this way, defect size and location can be detected by amplifying and running these signals.

13. Vibration Analysis (VA)

This method is a process of monitoring the vibration signatures specific to a piece of rotating machinery and analyzing it. It uses three types of sensors accelerometers, velocity sensors, and displacement sensors.

i) Basic Accelerometers – It uses a piezoelectric crystal that vibrates due to the part-motion to which the sensor casing is attached. As both the crystal and mass vibrate, it generates a low voltage current. Further, it passes through a pre-amplifier and sends it to the recording device. Accelerometers detect high frequencies very effectively.

ii) Basic Velocity Sensors – This uses a spring-mounted magnet. It moves through a coil of wire. The outer case of the sensor is attached to the part being inspected. As the wire-coil moves through the magnetic field, it generates an electrical signal. Further, it is sent back to the receiver and recorded for analysis.

iii) Displacement Sensors – This one uses an eddy current to detect vertical and horizontal motions.

14. Visual Testing (VT)

The method consists of visual observation of the test object surface for evaluating the surface discontinuities. These inspections may comprise line-of-sight vision, direct viewing, enhanced using optical instruments, and computer-assisted viewing systems. In most industries, Visual Testing techniques are commonly used for inspection.

Nondestructive Testing Equipment

The main purpose of NDT is to detect the discontinuities of an object despite affecting its future usefulness. In simple words, NDT allows a thorough careful evaluation of materials without any damage. Also, it is used to measure pores and cracks in materials that may be subject to a brittle failure.

The methods could be applied for material quality control purposes, life cycle, and service-related conditions of parts/materials.

The NDT equipment are handheld X-ray fluorescence analyzers and ultrasonic thickness gauges.

Nondestructive Testing Standards

The codes and standards are some specific instructions and guidelines for operation keeping in mind the properties of metals. The following are some of the more commonly used ASTM NDT standards or guidelines.

Standards Explanations
ASTM E709 Standard Guide for Magnetic Particle Testing
ASTM E1444 Standard Practice for Magnetic Particle Testing
ASTM E165 Standard Practice for Liquid Penetrant Examination for General Industry
ASTM E1417 Standard Practice for Liquid Penetrant Testing
ASTM E1208 Standard Practice for Liquid Penetrant Testing using the Lipophilic Post-Emulsifiable Process
ASTM E1209 Standard Practice for Liquid Penetrant Testing using the Water-Washable Process
ASTM E1210 Standard Practice for Liquid Penetrant Testing using the Hydrophilic Post-Emulsifiable Process
ASTM E1219 Standard Practice for Liquid Penetrant Testing using the Solvent-Removable Process
ASTM E114 Practice for Ultrasonic Pulse-Echo Straight-Beam Examination by the Contact Method
ASTM E164 Standard Practice for Contact Ultrasonic Testing of Weldments
ASTM E213 Standard Practice for Ultrasonic Testing of Metal Pipe and Tubing
ASTM E2375 Standard Practice for Ultrasonic Testing of Wrought Products
ASTM E94 Guide for Radiographic Examination
ASTM E1742 Practice for Radiographic Examination
ASTM E1000 Guide for Radioscopy
ASTM E1255 Practice for Radioscopy
ASTM E1030 Test Method for Radiographic Examination of Metallic Castings
ASTM E1032 Test Method for Radiographic Examination of Weldments
ASTM E999 Guide for Controlling the Quality of Industrial Radiographic Film Processing
ASTM E142 Method for Controlling Quality of Radiographic Testing
ASTM E2007 Standard Guide for Computed Radiography
ASTM E2738 Standard Practice for Digital Imaging and Communication Nondestructive Evaluation (DICONDE) for Computed Radiography (CR) Test methods
ASTM E268 Electromagnetic testing
ASTM E426 Practice for Electromagnetic (Eddy-Current) Examination of Seamless and Welded Tubular Products, Austenitic Stainless Steel, and Similar Alloys
ASTM E1962 Standard Practice for Ultrasonic Surface Testing Using Electromagnetic Acoustic Transducer (EMAT) Techniques

Nondestructive Testing Applications

NDT Testing is applied in most industries like automotive, marine, aerospace, oil/gas, and power. The industries use NDT to test machine conditions, quality control, condition assessment, and the quality of components before or during their active use.

Industry Purposes
Aerospace Testing Castings
Automotive Testing piston heads durability
Manufacturing Testing components quality before it goes into production
Marine Identify Corrosion
Medical Devices Testing stents’ durability and composition
Military/Defense Ballistics testing and analysis
Packaging Testing structure/chances of leakage for packages
Petrochemical Testing pipelines used to transport oil
Power Generation Test welding-related defects
Waste Management Identify redeemable metals in waste

Nondestructive Testing Schools

Before selecting an NDT School, aspiring applicants must consider things like location, program type, and affordability. There are many institutes in the United States and outside as well for NDT certification or degree programs. The following are some of the schools offering amazing programs.

  • American Aerospace Technical Academy (AATA)
  • American Institute of Nondestructive Testing (AINDT)
  • Clover Park Technical College
  • Cowley College
  • Great Bay Community College
  • Iowa State University (ISU)
  • Northeast Wisconsin Technical College (NWTC)
  • Ridgewater College
  • University of Illinois (UIUC)
  • Virginia Tech (VT)

Nondestructive Testing Courses

The are many institutes offering courses for NDT throughout the United States. Some of the prominent programs are as follows.

  • Acoustic Emission Testing (AE)
  • Electromagnetic Testing (ET)
  • Ground Penetrating Radar (GPR)
  • Guided Wave (GW)
  • Laser Testing (LM)
  • Leak Testing (LT)
  • Liquid Penetrant Testing (PT)
  • Magnetic Flux Leakage (MFL)
  • Magnetic Particle and Liquid Penetrant Testing (MT/PT)
  • Magnetic Particle Testing (MT)
  • Radiographic Testing (RT)
  • Thermal/Infrared Testing (IR)
  • Ultrasonic Testing (UT)
  • Vibration Analysis (VA)
  • Visual Testing (VT)

Nondestructive Testing Certification

There are many institutions that offer NDT certifications, a few of them is the American Welding Society and the American Society for Nondestructive Testing. Generally, there are three levels of NDT certification programs i.e. Level I, Level II, and Level III. The requirements for all Level 1,2,3 certifications look similar. As per the old edition, the qualification description is as follows.

NDT Level I

  • The candidates should be qualified to perform specific calibrations, specific NDT, and specific evaluations, and record results for acceptance or rejection determinations according to written instructions.
  • The NDT Level I should receive specific instructions and supervision from NDT Level II or III certified individuals.

NDT Level II

  • The individuals should be qualified to set up and calibrate equipment and interpret/evaluate results as per applicable codes, standards, and specifications.
  • They should be familiar with technique limitations.
  • They should organize and report the results.
  • Individuals should exercise assigned responsibility for on-the-job training and guidance of trainees and Level I personnel.


  • The individual should be qualified to develop, qualify and approve procedures, establish techniques, and interpret codes and standards.
  • They should have a sufficient practical background in applicable materials, fabrication, and product technology.
  • Individuals should be capable of training and examining Level I and II personnel.

Nondestructive Testing Benefits

NDT is an effective way for businesses to save both time and money. Using these technologies, companies are able to test qualities and find any potential corrosion, imperfections, or risks before the object becomes problematic. Normally, NDT has more advantages than disadvantages.

i) Safe Operating Method – It is a safe testing method for operators. Most of the techniques are harmless to humans. Yet, while using tests like radiographic testing, individuals must conduct it under strict conditions. Also, this method helps to prevent fatalities or injuries by ensuring machinery, structures, and components are safe.

ii) Cost-Effective Technique – NDT methods are economical in nature. Cost-effective means, they prevent the replace-need of an item before a malfunction occurs without destroying the piece itself.

iii) Verification/Testing Usage – The techniques employed for testing welds and welding procedures verifications. And this ensures that the welding process has been completed to the correct specification within the bounds of quality control. For example, the base metal has reached the correct temperature, cooled at a specific rate, and compatible materials have been used.

iv) High Inspection Accuracy – NDT testing is an accurate way of inspection. Because the test is repeatable and correlates the results, a number of tests can be used together.

v) Imparts Peace of Mind – These methods also give a sense of safety and peace of mind to operators by making sure equipment is functioning well, determining any measures, and preventing future accidents.

Nondestructive Testing Disadvantages

The disadvantages of NDT methods are few. They depend on the type of technique used on a component.

  • Components need to clean before and after inspection
  • In some cases, there might be a lack of depth sizing
  • Some NDT methods only can inspect relatively non-porous surfaces
  • Some of the test methods require electricity
  • Some tests are only effective on conductive materials
  • Sometimes, component finishing can affect the sensitivity of the inspection
  • Variations in magnetic permeability can affect some of the tests
  • Some tests can also create a bit of a mess, depending on the materials used for testing
  • Sometimes, hiring an experienced NDT technician requires more financial investment

NDT Handbooks

The following are some of the handbooks used in the industry.

Third Edition-

Volume 3 – Infrared and Thermal Testing
Volume 4 – Radiographic Testing
Volume 5 – Electromagnetic Testing
Volume 6 – Acoustic Emission Testing
Volume 7 – Ultrasonic Testing
Volume 8 – Magnetic Particle Testing
Volume 9 – Visual Testing
Volume 10 – NDT Overview

Fourth Edition

Volume 1 – Liquid Penetrant Testing
Volume 2 – Leak Testing
Volume 3 – Radiographic Testing
Volume 4 – Thermal and Infrared Testing

Nondestructive Testing Jobs

The NDT technicians provide quality assurance in various settings during the job. Most commonly, they are employed in the industries like railways, aviation, pipelines, construction, manufacturing, and industrial plants (petrochemical, nuclear, refineries, power, fabrication shops, etc.)

Note: Aspiring applicants can search for NDT Jobs in the United States.


Nondestructive Testing (NDT) methods are very popular in the industry for their usage in various forms on different objects/parts. Basically, they provide any potential malfunctioning in the machinery or any part of it before or during its use. Additionally, these techniques ensure machinery life before destroying them completely. Thus, the above information on NDT methods is useful in many forms for technicians, operators, companies, and other individuals working in the welding industry.

Related: Other Welding Technology Topics

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