Everything You Need To Know About Nondestructive Testing

Nondestructive Testing (NDT) is a critical requirement in running day-to-day operations in companies. NDT procedures protect not only the people but also ensures that production processes meet required standards. With NDT, industries can manufacture safe products. In terms of cost, NDT is economical and cost-effective. Nondestructive testing technicians are trained to utilize various technologies to perform inspections and analyze procedures and equipment necessary to ensure that all company's operations are safe and reliable.

What is Nondestructive Testing?

NDT, or Nondestructive Testing, is an effective way to check the mechanical quality of many different materials while keeping them structurally sound. This means the part can be tested with it still attached to an aircraft, while fluid is flowing through a pipe, or even in an operational nuclear power plant. NDT is a way to ensure the safety of the general public by making sure tested parts meet strict guidelines and stringent procedures are followed.

Nondestructive Testing Methods

While there are many different NDT test methods, Spartan College of Aeronautics and Technology nondestructive testing technology program focuses on six techniques. Our current NDT methods include:

Visual Testing (VT)

Also known as visual inspection, visual testing is a popular NDT method that involves collecting visual data on the test object without altering it. You can either use a naked eye to observe or non-specialized optical equipment like magnifying glasses, mirrors, borescopes, and computer-assisted systems.

Visual testing helps evaluate the intensity of surface defects such as corrosion, misalignment, and cracks. This method is mostly used in terms of welding. At Spartan College of Aeronautics and Technology, we offer courses that give you in-depth knowledge on how to visually recognize material defects and utilize various tools and gages to take precise measurements.

Liquid Penetrant Testing (PT)

Liquid penetrant nondestructive testing identifies imperfections in a material by applying a low viscosity liquid on a components surface. As the liquid spreads, it seeps into the surface defects such as cracks, surface porosity, and leaks. Excess liquid is then drawn out using a developer, leaving visible indications of the defects. Liquid penetrants containing visible dyes provide better contrast with the developer.

At Spartan College, we utilize various penetrant dyes and developers to equip your skills on liquid penetrant setup, application, and interpretation of the resulting indications.

Magnetic Particle Testing (MT)

Magnetic particle testing uses magnetic fields to detect defects on surfaces or in shallow sub surfaces. This method works only in ferromagnetic materials. A magnetic field is first created on the inspection area. In the defect-free parts of the test object, the magnetic flux remains steady, while in the presence of cracks, pores, and other defects, some magnetic lines are displaced. Magnetic poles and a magnetic field then form above the defect. The ferromagnetic particles in the magnetic field get influenced, magnetized, move to the defect area, and create cluster strips. This formation allows the detection of the tiniest of hair cracks since the strip width is more than that of the cracks and other defects.

Does it sound complex? At Spartan College, we break it down for you in theory and practical equipment setup, application, and train you on how to interpret and measure magnetic particle testing indications.

Ultrasonic Testing (UT)

With UT nondestructive testing, it involves the transmission of high-frequency sound waves into a material to identify the flaws. Short waves and frequencies of up to 50MHz are more favorable in this method. Simply put, ultrasonic testing utilizes ultrasound (AKA high-frequency sound waves that produces imaging within objects) to perform inspections. The ultrasonic inspection process involves passing a transducer connected to a flaw detector over the inspection material. The transducer is normally coupled to the test object by gel, oil, or water for efficient sound transmission.

The pulse-echo is among the most common types of ultrasonic testing techniques. The method entails the direction of vibrations into the material and obtaining the intensity of the echo caused by defects on the object surface. There are advanced ultrasonic testing techniques which include, Phased Array Ultrasonic Testing (PAUT), Time-Of-Flight Diffraction (TOFD), and Automated Ultrasonic Testing (AUT).

Ultrasonic testing is commonly used to measure and ascertain object thickness, especially in the pipework.

Radiographic Testing (RT)

Radiographic testing is an NDT technique that utilizes gamma rays or x-rays to identify defects on materials by assessing their internal formation. The test material is usually placed between the radiation source, such as a radioactive isotope or an X-ray generator, and the detector. The test material thickness and density reduce the radiation penetration through absorption or deflection. The absorption variations are then recorded on the sensors. It is these readings that uncover the internal aspects of the inspected object when electronically processed.

A radiographic testing course at Spartan College offers training on a wide range of imaging techniques in industrial radiography such as Film Radiography, Digital Radiography, and Computed Radiography. We equip you to safely produce radiographs using x-ray tubes, digital imaging, automatic film processing, and film viewing and interpretation.

Eddy Current Testing (ET)

Eddy current testing is a nondestructive testing method that uses the electromagnetism principle to locate defects in a material. When the testing surface interacts with the magnetic field resulting from a highly energized coil, it produces an eddy current. The operator monitors and measures the magnetic permeability and electrical conductivity variations to determine whether there are defects. The presence of defects alters the density and amplitude of the measured current.

At Spartan College, we train you to calibrate the standard and acceptable procedures, testing conductivity, and different eddy current testing methods.

There are other methods that are subcategories of the above techniques, which are also used in inspections, such as leak testing, hydrostatic testing, digital thermography, and acoustic emission testing.

Where Is nondestructive Testing Used?

NDT is used in many of today's industries, such as pipelines, high-steel construction, bridgework, automotive, aviation, and shipbuilding. This is just a short list; there are almost too many applications to name. Many folks do not realize all the work that goes into the bridges, buildings, airplanes, ships, and automobiles to make them safe and reliable. However, NDT is one of those "behind the scenes" jobs that is done that we may never have known about. We will just say that not all heroes wear capes.

Here are some of the positions you can potentially take up in these industries after successfully training in NDT:

Eddy Current Technician

As an eddy current technician, you plan, prepare, and set up equipment and examine the system(s) to locate and identify cracks or other defects. You are also able to troubleshoot, perform preventative maintenance tasks, and repair machines. Due to your expertise, you supervise and train lower personnel on inspection evaluation and examination of the test results.

Eddy current technicians are also responsible for the calibration of test equipment using standard practices depending on the type of inspection you are conducting.

Magnetic Particle Technician

As a magnetic particle technician, you generate, update, and prepare documentation based on the test performed. The reports consist of test results and procedures which aid in engineering and production. It is your interpretation of test results that determine whether the tested materials are useful or not. 

Also, you examine the condition of engine parts and shafting to ensure they are functioning as expected.

Ultrasonic Testing Technician

As an ultrasonic testing technician, you inspect surfaces with dye penetrant materials. After inspection, you interpret and evaluate the results on a range of weldments castings and materials obtained from various methods. You also actively support the research and development of systems that match the crucial requirements and processes.

You are also responsible for performing a visual inspection, volumetric NDE inspections with advanced ultrasonic equipment, and assisting in developing NDE inspection procedures for complex structures.

Industrial Radiographer Assistant

An industrial radiographer assistant's roles entail performing radiographic inspections to ASME, ANSI, AWS, and API-related codes and standards. Other responsibilities include:

• Training other assistant radiographers.
• Ensuring the radiographic equipment is safe and secure.
• Preparing inspection reports.
• Interpreting the results per code of customer needs.

Industrial Radiographer

As an industrial radiographer, you are responsible for all radiographic procedures in the company, including selecting appropriate techniques, positioning materials, exposure of the film, etc., to identify and assess defects in castings and weldments. Employers require your knowledge and skills in radiography to help capture images that may otherwise be impossible.

As part of your roles, you are required to conduct research, present the finding to other members of your team and prepare the necessary documentation for inspection.

Start Your Nondestructive Testing Technology Training Today

With training in NDT, the opportunities to choose your path opens up to what you’re interested in training in. NDT opens the door to many sectors. Do not wait any longer; enroll today at Spartan College to get the career oriented training in NDT you’ve been looking for.

Click here to begin the Spartan College enrollment process.