What Is NDT Testing – Equipment Guide & Best Applications
Traditionally, collecting data about different materials required testing methods that resulted in damage to the material under study. Non-destructive testing (NDT) gives inspectors a chance to learn about materials without damaging side effects.
You can learn more about these processes, the best ways to apply them, and the equipment used in NDT in this article. If you have any questions after you finish this article, feel free to contact our team at MFE Inspection Solutions. You can reach us at 844-867-3686.
What is Non-Destructive Testing?
Non-destructive testing allows technicians to gather information about the state of your equipment without causing any damage to said equipment. Crews use NDT methods to detect corrosion, perform penetrant testing, handle vibration analysis, and other necessary assessments.
This form of testing allows crews to detect defects and perform quality control without damaging your equipment, saving you money in the long run. Note that NDT methods go beyond visual testing and provide detailed information about your equipment.
What is Non-Destructive Equipment?
Technicians use non-destructive testing equipment to perform non-destructive testing. There are several common forms of non-destructive testing, so the professionals use many different forms of equipment, depending upon the process they plan to carry out.
During NDT inspections, testing crews generally bring their own specialized equipment along. You may ask about the specific equipment required for the NDT techniques used in your facility to learn more.
What is the Difference Between Destructive and Non-Destructive Testing (NDT)?
What is destructive and non-destructive testing? These forms of testing both play a role in equipment maintenance. Testing allows professionals to fully assess the condition of mechanical components by focusing on their:
- Materials
- Design
- Structure
We look at the condition of the tested component following the assessment to determine if a test is destructive or non-destructive. Destructive testing methods either destroy or damage parts.
Non-destructive testing, on the other hand, does not cause damage to tested equipment. For this reason, many companies prefer NDT methods.
Examples of Destructive Testing
Some industries use both destructive and non-destructive testing. Examples of destructive testing – which destroy the material or equipment tested – include:
3-Point Bend Testing
During this testing procedure, mechanical engineers focus on assessing the flexibility of a material. They take a sample (traditionally referred to as a “coupon”) and bend it into a specified angle. The test requires technicians to bend the material at three distinct points.
Macro Sectioning
Inspectors perform macro sectioning when testing welded material. They extract a section of the material, often etching it during the examination process.
Tensile Testing (Tension Testing)
Sometimes, businesses need to know the material’s failure point or find out how the material would respond to certain conditions. In this situation, they may perform tensile testing using the application of controlled tension.
In many industries, businesses use both destructive and non-destructive testing to ensure products and equipment continue to work correctly. Both forms of testing have an essential role to play.
Why Use Non-Destructive Testing?
Nondestructive testing provides you with many benefits. This form of testing ensures that your equipment and assets function correctly without damaging them in the assessment process.
The experts often recommend NDT methods because they:
Increase Your Savings
Businesses save resources and money by carrying out NDT tests instead of destructive testing. Your equipment comes out of the other side of the testing process intact if you use non-destructive testing, meaning you do not have to replace it after the test.
Represent Safe Testing Options
Most NDT tests have no potential to harm people, allowing you to feel confident about this testing method. However, remember that radiographic testing may be dangerous to people if performed incorrectly.
Work Efficiently
Efficiency matters for businesses around the country. Generally, NDT methods allow for quick and thorough assessments, meaning you can quickly get back to total production. Destructive methods often take longer to complete.
Provide Accurate Results
Equipment assessments should provide you with accurate results. NDT methods give you predictable results with a high degree of accuracy, allowing you to feel confident about the condition of your equipment and worker safety.
What Industries Use Non-Destructive Testing?
Many different industries use nondestructive testing. Companies often use this form of testing for quality control and condition assessment for equipment. A non-exhaustive list of industries using the NDT testing method includes:
- Aerospace Engineering
- Automotive
- Manufacturing
- Medical devices
- Military
- Mining
- Packaging
- Marine Industries
- Petrochemical Industry
- Power Generation
- Waste Management
These industries use NDT tests to assess casings and components. For example, they often look at the durability of different components, look for leaks, and check for defects in products before they ship out.
The nondestructive examination allows companies in these industries to ensure their equipment and products are safe for use efficiently and effectively
Organizations That Regulation Non-Destructive Testing
NDT techniques are generally safe for workers and inspectors. However, tests often assess the functions of equipment like pressure vessels and boilers, which may malfunction and lead to injuries if not handled correctly.
These pieces of equipment require careful maintenance to avoid dangerous failures. Therefore, many industries require businesses to adhere to strict safety regulations and follow clear-cut inspection codes, including when handling NDT.
The exact regulations designed to handle NDT vary by country and industry. Examples of organizations that regulate NFT include:
- ASTM (American Society for Testing and Materials)
- ASNT (American Society For Nondestructive Testing)
- COFREND (French Committee for Non-destructive Testing Studies)
- CSA Group (Canadian Standards Association)
- CGSB (Canadian General Standards Board)
It’s essential to follow all regulations issued by the applicable organization in your area. NDT technicians can provide information about these regulations and how they apply to various inspection techniques.
Equipment Used in NDT
What is NDT equipment? There are many types of NDT inspections performed in different industries. Therefore, there is no set list of tools used in non-destructive testing. Instead, inspectors may use everything from their eyes to high-tech machinery to detect defects in various pieces of equipment.
You can learn more about different forms of testing to learn more about the possible equipment required for testing procedures.
Types of Non-Destructive Testing
You can explore different non-destructive inspection techniques right here. Depending upon your industry, you may utilize one or more of these testing methods.
Visual Testing
Performing a visual inspection represents the most basic form of NDT testing. Technicians look at the equipment, material, or asset and notice flaws during visual inspections. They may also use a specialized device to handle a Remote Visual Inspection.
Visual testing often provides an excellent place to start assessments, but you may require more in-depth assessments to get definitive results. Find out more about visual inspections with our team.
Vibration Analysis
Technicians use vibration analysis when checking on rotating parts within a piece of machinery or equipment. Each material has a distinct vibration signature, and by assessing these signatures, crews can check on their overall function.
This form of analysis requires a vibration meter device and may also involve other sensors. These sensors can keep track of factors like acceleration, displacement, velocity, looseness, and misalignments. Based on the vibration signatures they detect, they may approve a piece of equipment or suggest repairs.
Weld Testing
Inspectors commonly end up testing welds while handling industrial assets. Technicians focus on assessing the strength of the weld while looking for any defects that could impact the integrity of the finished equipment or structure.
A technician may perform a weld inspection to look for issues caused by fatigue, incorrect techniques, or environmental damage. In addition, they often look for the presence of slag as they work to detect flaws in the weld.
After making a preliminary determination with visual testing, technicians may perform other tests to assess the welding process.
Here is an example of the MFE team using remote visual inspection equipment to get the job done:
Magnetic Particle Testing (MPT)
Magnetic particle testing (MPT) involves looking for the flaws in ferromagnetic materials by assessing any disruptions in the flow of their magnetic field. Inspectors perform these tests by inducing a magnetic field and introducing iron particles to the material’s surface.
Inspectors observe the movement of the magnetic particles to look for imperfections. Assessing the magnetic field in this way allows technicians to check on the state of equipment without damaging the material.
Magnetic particles should not cause any health risks to inspectors.
Magnetic Flux Leakage
Magnetic flux leakage testing utilizes a strong magnet, which creates a magnetic field that crews use when assessing structures made of steel. Technicians use sensors to track any changes in the magnetic flux lines or density, which may indicate issues like:
- Pitting
- Erosion
- Corrosion
Monitoring the magnetic field allows crews to assess issues with large structures without causing any damage. Technicians often spend a significant amount of time studying magnetic field science and magnetic flux density before completing these tests.
Liquid Penetrant Testing
Liquid penetrant tests indicate breaks or defects in the surface of pieces of equipment. Technicians perform liquid penetrant testing by applying a liquid that contains either a visible dye or a fluorescent dye to the surface of an object.
The inspectors rub away excess liquid; any liquid that remains behind indicates a defect. Once crews notice the flaws, they examine them in greater detail with ultraviolet (UV) lights if they use a fluorescent dye.
Penetrant testing works very well to identify defects, and technicians can easily clean up after the process by washing away the last of the dye.
Ultrasonic Testing
Inspectors use high-frequency sound waves during ultrasonic testing. They transmit the sound waves at the material or asset under inspection and look for any property changes. Many forms of ultrasonic testing use pulse echoes, which involve looking for surface imperfections based on the echoes reflected off of an item.
In addition to pulse-echo tests, crews may perform Through Transmission Testing (TTT), which utilizes transducers to measure the material’s porosity.
Technicians may also use Time of Flight Diffraction (ToFD) to look for discontinuities in different materials. For example, crews may use this form of testing during rear wall inspections. Finally, you may want to consider immersion testing for the ultrasonic testing performed in an immersion tank.
Acoustic Emission Testing
Technicians use acoustic emissions to look for defects and imperfections with this NDT testing method. First, they monitor acoustic energy bursts, focusing on the location of the burst, its intensity, and its arrival time.
Acoustic emission testing works well for companies operating in many different industries.
Phased Array Ultrasonic Testing (PAUT)
Phased array ultrasonic testing serves as a variation of traditional ultrasonic testing. This kind of test uses an array that can create independent pulses. Technicians control how each element fires, allowing them to steer or focus the sound beams.
They can move the beam to various depths and angles, easily generating cross-section views of equipment or materials. Some examples of PAUT used a virtual probe to gather additional information in this NDT method.
Electromagnetic Testing (Eddy Current Testing)
During ECT testing, technicians often use a form of electromagnetic testing called eddy current testing. This process allows crews to measure the magnetic field of a material based on its eddy currents (or electrical currents).
Eddy current testing generally works best on non-ferrous materials.
Technicians use eddy current testing to find defects in a piece of equipment or material. Sometimes, crews blend this process with remote field testing. Remote field testing allows companies to test ferrous pipes for structural integrity and other flaws.
Radiographic Testing
Technicians use radiation to complete radiography testing. Often, crews use x-rays if they’re dealing with thin materials. However, they may choose gamma radiation instead if they need to assess a dense or thick material, requiring a thickness measurement before beginning the assessment.
Experts use a variety of processes to report the results of radiography testing. For example, they may use computed tomography, computed radiography, digital radiography, or film radiography. The results may show any defects in the material tested.
Industrial radiography – and testing – is used in many different industries worldwide. Depending on the equipment under review, crews may use computed tomography and other assessment techniques.
Neutron Radiographic Testing
Neutron radiography is one of many NDT techniques. Trained inspectors utilize low-energy neutrons during this form of testing. Crews can see the beam in many organic materials, allowing technicians to assess equipment’s internal components when looking for possible flaws.
Thermal Testing
Some industries use infrared (or thermal) testing. These tests assess the wavelength of different forms of light to determine the condition of various objects or pieces of equipment.
There are two primary forms of thermal testing: passive and active thermology. Passive forms of thermal testing utilize sensors to assess emitted radiation. The testing results allow crews to find bearings, electrical components, or motors that are overheating.
Crews use active thermography to look at a structure’s temperature gradient. This test can find bonding defects and surface delaminations within a structure.
Mass Spectrometer Testing
Mass spectrometer testing represents one option used to carry out leak testing. Technicians place materials inside a test chamber to complete this test and introduce either helium or a helium-air mix to the chamber.
They may also complete this form of testing in a vacuum, looking for ionized helium.
Guided Wave Testing (GWT) Leak Testing
Technicians use several non-destructive testing methods to check for leaks, including:
- Bubble Leak Testing
- Pressure Change Testing
- Halogen Diode Testing
Technicians submerge equipment in a tank of liquid to look for gas leaks with bubble leak testing. However, some pieces of equipment are too large to submerge. In these cases, technicians apply a soap solution to the surface of the equipment and look for bubbles.
If you have a closed system, technicians may use pressure change testing. They look for losses in either vacuum or pressure to identify possible leaks.
Finally, you may schedule halogen diode pressure testing. Crews mix a tracer gas and air and then “sniff” out leaks with a halogen diode detection unit.
You may use this NDT inspection to test pipes that stretch across long distances. The tests use ultrasonic waveforms to detect any issues in the walls of the line. Guided wave testing returns the results to a computer, allowing crews to look for possible problems.
Companies can order either guided wave medium-range ultrasonic testing (GW MRUT) or guided wave long-range ultrasonic testing (GW LRUT). You may assess areas hundreds of feet away from the starting location with GW LRUT testing.
Ground Penetrating Radar (GPR)
Technicians use radar pulses for this NDT. They emit the pulses into a structure below the ground’s surface, including materials like ice, rock, or soil. How the waves reflect can help technicians identify material boundaries or buried objects.
Laser Testing Methods
There are three primary kinds of laser tests used in NDT testing. Your company may decide to use:
- Holographic testing
- Laser profilometry
- Laser shearography
Crews use lasers to look for changes in a material’s surface with holographic testing. Generally, technicians perform this kind of testing on materials exposed to stressors like vibrations, pressure, or extreme. Then, crews compare the results to a piece of material never exposed to these stressors.
Technicians utilize a rotating laser to handle laser profilometry. This process looks for cracks, erosion, corrosion, and pitting and projects the results as a 3D image.
Finally, some industries use laser shearography, which creates images of a material before and after it experiences stress. You can learn more about laser testing with members of our team.
Non-Destructive Testing – 5 Unique Applications
What is non-destructive testing? NDT focuses on assessing issues with materials or equipment without causing any damage during the process. The unique applications associated with this form of testing provide several applications, including:
#1: The Ability to Detect External Flaws
Sometimes, equipment or materials have flaws in their exterior casing. However, these flows may be microscopic, making them hard to identify with only a visual inspection. NDT testing allows technicians to identify these flaws before they become a problem.
#2: Help Identifying Internal Flaws
Assessing the inside of a part or piece of equipment poses unique challenges, especially if you want the equipment to continue functioning afterward. NDT inspectors have various assessment tools at their disposal to handle these tests.
#3: Testing Untouchable Objects
How do you test for defects on an object underwater or in a high-temperature environment? NDT provides a way to assess the condition of these parts without destroying them, without exposing technicians to dangerous situations in most cases.
#4: NDT Allows for Medical Assessments
We’ve primarily focused on the industrial uses of NDT. However, these tests play an essential role in most medical testing, as doctors do not want to damage their patients while carrying out tests to assess their health and well-being.
Going for a check-up at the doctor may involve a non-destructive inspection as medical professionals take your pulse, check your blood pressure, and assess your reflexes. In addition, doctors use other NDT technology when they take an X-ray to look at a broken bone or perform a CAT scan to look for other internal injuries.
#5: NDT Determines Machinery’s Lifespan
Different machines wear down at different rates, and it can be difficult to tell when a machine is on its last legs. NDT inspections can help determine the rate at which a machine is degrading and how much longer it is likely to be useful before needing to be replaced.
Speak to Us to Learn More About NDT
Are you interested in NDT techniques for your business? You can get professional help reviewing the tests that might work best to address your needs by reaching out to our team at MFE Inspection Solutions.
We focus on staying on the cutting-edge of emerging NDT technology. Our technicians constantly educate themselves about new forms of testing to provide you with the optimal configuration for your business needs. Find out more about your options by calling us at 844-867-3686 or send us an email.
We’re ready to offer our advice and expertise to you.