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What Are the Most Popular NDT Methods Used for Welding?

calendar Oct. 18, 2021user-iconTXNDT

Nondestructive testing is an important process that supports a wide variety of industries that keep the world as we know it functioning at top capacity. From infrastructure to renewable energy to utilities, nondestructive testing is vital to maintain a safe and efficient world.

In many of the industries supported by nondestructive testing, welding is used to create, join, and repair assets. Nondestructive testing methods can be specific to the component’s materials, location, and ease of access, to list a few.

When it comes to assets that have been welded, there are three specific methods that are used most often: liquid penetrant testing, magnetic particle testing, and ultrasonic testing.

Here is why these methods are popular NDT choices for welding.

Liquid Penetrant Testing

Liquid penetrant testing is a commonly used method of nondestructive testing for all types of jobs and materials, but especially for welded materials.

Liquid penetrant testing is a nondestructive testing method in which capillary action finds flaws or discontinuities by using a low viscosity liquid poured over the surface of the component. The property of capillary action causes the penetrant to enter any fissures or voids that may be present in the asset’s surface. After all excess penetrant is removed, the flaws or voids will be indicated.

This method of testing works well for welding because of how easily the liquid penetrant can identify flaws in the weld. A secure weld will not allow any penetrant in. If any of the liquid flows through the weld, a flaw is indicated, and the technician will know immediately where the flaw is.

Magnetic Particle Testing

Magnetic particle testing is another common nondestructive testing method. Much like liquid penetrant testing, magnetic particle testing involves applying a substance to the surface of the part. Magnetic particle testing uses a fine, pigmented ferromagnetic powder on the surface of the part. Since magnetic particle testing must be performed on ferromagnetic materials, when the magnetic field is applied to the component under inspection, the pigmented powder will be drawn into any flaws or discontinuities, creating a visible indication.

This method is effective for welding because carbon steel welds are ferromagnetic and therefore can be tested effectively through magnetic particle testing.

Ultrasonic Testing

Many technicians agree that the best testing method for welds is ultrasonic testing. Ultrasonic testing is the process by which high frequency sound waves are applied to the component to detect flaws. Using a sending unit and transducer, sound waves will travel through the component under inspection, and any flaws will be indicated on the indication screen.

Ultrasonic testing is one of the most precise methods of nondestructive testing, so it can quickly and accurately identify flaws in welds without labor intensive set-up and with simple equipment. A technique known as phased array involves using multiple transducers to scan a broad region of a weld, increasing this method’s efficiency.

Contact TXNDT Today!

Welding is an important part of fields like manufacturing, infrastructure, and utilities, among many others. It is critical that nondestructive testing technicians are well-versed in the best ways to approach welded materials.

If you are looking to become a technician through NDT technician training or hire nondestructive testing services to protect your assets, it is crucial to choose the right company to meet your NDT needs, especially if you have welded materials that need servicing.

TXNDT is a cut above the rest with superior NDT courses, knowledgeable instructors, and hands-on coursework to prepare all prospective technicians for NDT certification. Check us out online or give us a call today at 281-231-0001 to see how TXNDT can work for you!