Published on 15-Feb-2024

A Materials Guide to Ultrasonic Testing Applications

A Materials Guide to Ultrasonic Testing Applications


Ultrasonic Testing (UT) has emerged as a pivotal technique in material testing, offering a highly accurate method for assessing the integrity of materials like a materials guide.

Ultrasonic testing uses high-frequency sound waves to detect internal flaws in materials. 

Techniques like thickness testing, flaw detection, and density measurement are essential for understanding their applications and determining their effectiveness. 

Material Testing In Ultrasonic Testing

Non-destructive Testing (NDT) ultrasonic testing equipment provides outstanding capabilities to nondestructively measure thickness, locate defects, and test the structural integrity of a material or component:

UT thickness gauges can measure thickness in most engineering materials

Ultrasonic/phased array flaw detectors can locate and size hidden cracks, voids, disbands, and similar discontinuities in a wide range of materials

These ultrasonic testing instruments are used in many applications across the aerospace, automotive, railway, mining, and oil and gas industries.

Listed in alphabetical order, here are the various applications you can perform using ultrasonic testing:

  • Aluminum

Aluminum cans used in the beverage industry are routinely inspected for wall thickness accuracy.

With ultrasonic ndt gauging, you can measure wall thickness instantly and digitally by simply coupling ultrasound into the part from the outside.

  • Austenitic (and Other Alloys)

Austenitic materials account for 70% of all commercially produced stainless steel, which is primarily due to its good resistance to corrosion.

Corrosion-resistant alloys (CRAs) and Babbitt metals fit into this material group. Ultrasonic testing is helpful when inspecting:

 * Thick wall, thick components

 *Thick, dissimilar welds

 *Thin-walled austenitic steel inspection of pipes, where standard linear shear-wave inspection is impossible

  • Carbon Steel

Structures made of carbon steel are subject to corrosion that reduces the original thickness of the material.

If undetected over time, corrosion will weaken walls and can cause dangerous structural failures.

Both safety and economic considerations require that metal pipes, tanks, or structures that are susceptible to corrosion are inspected regularly.

Ultrasonic inspection enables you to accurately detect potential internal corrosion without damaging the material while accessing one side of the surface, even through paint and at hot temperatures (while in service).

Axial inspection of metal pipes is another possibility using our ultrasonic testing NDT equipment and scanners.

Along with corrosion measurement involving metal pipes and tanks, precision thickness measurement during the manufacturing process is another application.

One example is the measurement of the wall thickness of hollow turbine blades for aircraft engines, both to detect core shifts during manufacturing and to gauge wear in service.

Ultrasonic testing for welds and steel on pipes and other tube geometry is also a challenge that ultrasonic examination equipment, such as an NDT ultrasonic testing industrial scanner, can meet both acoustically and mechanically.

  • Castings

The wall thickness of hollow ferrous and nonferrous castings can be measured by ultrasonic testing methods, even those with complex shapes like engine blocks.

Ultrasonic NDT testing can also be used to check nodularity in cast iron.

Voids, porosity, inclusions, and cracks in the metal can occur during the casting process.

These conditions produce ultrasonic test indications that can be identified by a trained operator using an ultrasonic flaw detector with the appropriate transducers.

Additive manufacturing, which is expanding rapidly in the composites industry, is also used for castings.

  • Ceramics

Most structural and electronic ceramic components are well suited for ultrasonic testing inspection.

Fired ceramics can generally be measured over a wide thickness range and with a great degree of precision.

Ultrasonic gauges can be used to measure the thickness of structural ceramic products, such as turbine blades, valves, and other engine components.

Elastic modulus can also be calculated through the measurement of longitudinal and shear wave velocities.

  • Clad Metal Cookware

Conventional ultrasonic testing work enables the monitoring of the thickness of clad metal cookware, which incorporates a stainless steel body with a base made from a relatively thick core of either copper or aluminum sandwiched between two thin layers of steel.

This is important for quality control, as manufacturers of clad cookware need to monitor the thickness of the three layers comprising the base.

  • Composites 

Composites are often stronger and lighter than conventional materials (such as aluminum, steel, or even titanium). Ultrasound during the ultrasonic testing procedure enables the detection of inner and outer skin disbands , the presence of fluids, and crushed cores.

The increasing use of aircraft with composite structures has created the need to quickly check for impact damage at the airport during plane turnaround, for example.

Phased array ultrasonic testing applications can be used for full volumetric inspection of complex aerospace composite parts.

Also, ultrasonic thickness measurements of aerospace composites can be made instantly on parts such as wings, fuselage, ducts, panels, and fan blades.

Materials that fit into this category include carbon fiber (CFRP) and glass fiber (GFRP).

  • Fiberglass

Materials Guide to Ultrasonic Testing Applications in thickness gauges can be used for various fiberglass applications by measuring parts from one side.

Fiberglass storage tanks and pipes, for example, can be checked as part of the manufacturing process and while in service to help ensure that no erosion or delamination from corrosive chemicals has occurred.

Thickness gauging of fiberglass boat hulls and the measurement of fiberglass gelcoats are also known uses of ultrasound in the boating industry.

  • Glass

Glass is an inexpensive and highly versatile engineering material that can be cast, molded, or blown into a wide variety of shapes. It’s also highly transmissive to high-frequency sound waves, making it an excellent material for ultrasonic thickness gauging.

The geometry of most common glass products makes mechanical thickness measurement with calipers or micrometers difficult or impossible. However, virtually all common glass products can be easily measured with ultrasonic thickness gauges.NDT techniques doesn’t damage the glass, and thickness measurements are instant, accurate, and reliable.

  • Gold

Ultrasonic flaw detectors can also help ensure a gold bullion bar is homogeneous and free of insertions.

The sound waves from the flaw detector will reflect from the bottom of the gold bar, an insertion within the gold bar (e.g., a tungsten metal insertion), or an internal void. You can use a flaw detector to distinguish between the waves reflecting from the bottom of the gold bar and waves reflecting from insertions or internal voids.

  • Iron

Ultrasonic testing equipment can be used to measure the degree of nodularity in cast iron or distinguish nodular iron from gray iron.

This NDT test technology is helpful for foundries that need to check nodular iron for uniformity.

  • Liquid

If you need fast, automatic measurement of the liquid levels in a large number of containers going through a filling process, ultrasonic liquid level measurement is a good solution.

Ultrasonic testing can measure liquid levels on tanks/pipeline using a noninvasive method (direct level measurement) or detect the presence or absence of liquid in a sealed container (presence/absence test).

There are are many applications for underwater ultrasonic testing due to hygge demand. 

  • Mining Equipment

In the mining industry, phased array ultrasonics and ultrasonic transducers offer many benefits to heavy equipment component inspections, such as:

Thick wall lug and bore inspections

Gear inspections inside mining equipment

Inspection of an excavator’s swing shaft component

  • Plastic

All common plastics can be measured ultrasonically. Examples include:

Multilayer packaging used for food products and beverages

Automotive air bag cover tear seams

Fuel tanks

Polymer aircraft windshields

Also fitting into this material category is high-density polyethylene (HDPE), a versatile thermoplastic used in piping and many other fabricated parts and components.


Sound attenuation in rubber is typically high in comparison to other materials, but thickness can usually be measured with high-penetration gauges.

Common applications include:

Wall thickness of rubber tubing

Total thickness and depth of reinforcement in rubber conveyor belts

Tread thickness in tires


Some aircrafts structural parts, such as the engine mount and frame, are built with titanium casting. This material is very difficult to inspect because of its large grain structure. Using ultrasound phased arrays to inspect titanium castings offers much better detectability than conventional methods using X-ray or ultrasound technology.


Some aircrafts structural parts, such as the engine mount and frame, are built with titanium casting. This material is very difficult to inspect because of its large grain structure. Using ultrasound phased arrays to inspect titanium castings offers much better detectability than conventional methods using X-ray or ultrasound technology.

What are the applications of Ultrasonic Testing?

Ultrasonic Testing is like giving materials a guide to a health check-up using sound waves.

It involves sending high-frequency sound waves through a material to detect flaws or changes in its properties.

Ultrasonic Testing is a versatile technology with applications spanning various industries to underwater Ultrasonic Testing.

Here are a few applications. 

1. Manufacturing Quality Control

UT is the unsung hero in manufacturing. It ensures the quality of welds, detects hidden defects in materials, and guarantees that the products rolling off the assembly line meet the highest standards.

2. Ensuring Structural Integrity

Imagine Ultrasonic Testing as a guardian for structures. It plays a crucial role in ensuring the structural integrity of bridges, buildings, and other construction.

By detecting flaws invisible to the naked eye, it helps prevent potential disasters.

3. Aerospace Precision

In the Aerospace Industry, precision is paramount. UT steps in as the quality control expert, verifying the integrity of critical components in aircraft and spacecraft.

This ensures the safety of flights and space exploration missions.

4. Medical Imaging and Diagnostics

UT has a role in healthcare too. It contributes to medical imaging and diagnostics, providing detailed insights without invasive procedures.

It's like a medical detective, revealing the mysteries within our bodies.

5. Construction Assurance

Constructing the future? Ultrasonic Testing ensures the materials used are of top-notch quality.

It acts as a proactive measure, identifying potential issues before they become major concerns in construction projects.

6. Oil and Gas Industry

In the Oil and Gas Sector, where safety is paramount, UT is a key player.

It's used for inspecting Pipelines and critical equipment, ensuring the reliability and safety of operations.

7. Automotive Excellence

UT is part of the automotive quality assurance process. It checks the integrity of welds and ensures the reliability of crucial components, contributing to the overall safety of vehicles on the road.

8. Electronics and Semiconductor Industry

In the world of electronics and semiconductors, precision is everything.

Ultrasonic Testing assists in checking for defects in electronic components and ensuring the flawless performance of delicate devices.

9. Marine Environment Inspection

UT isn't afraid to get wet. It's used for underwater inspections in marine environments, ensuring the structural integrity of ships, offshore platforms, and other submerged structures.

10. Railway Safety Checks

For the railway industry, Ultrasonic Testing is a valuable tool for inspecting tracks and components.

It helps detect hidden flaws that could compromise the safety and reliability of railway systems.

These applications highlight the breadth of Ultrasonic Testing's reach. From the microscopic world of electronics to the grand scale of construction, UT ensures the quality, safety, and reliability of materials in diverse industries.


Ultrasonic Testing (UT) stands as a cornerstone in material evaluation, with applications spanning diverse industries.

Its non-destructive nature and high precision make it an invaluable tool for ensuring safety, reliability, and quality across various sectors.

Key Takeaways

  • UT is a pivotal technique in material testing, providing non-destructive and highly accurate assessments.
  • High-frequency sound waves are used to detect internal flaws in materials.
  • Essential techniques include thickness testing, flaw detection, and density measurement.
  • NDT Ultrasonic Testing Equipment is crucial for nondestructive measurement of thickness, defect location, and structural integrity.
  • UT instruments are widely used in the aerospace, automotive, railway, mining, and oil and gas industries.
  • Inspection of beverage cans for wall thickness accuracy using ultrasonic gauging.
  • Inspection of thick components, dissimilar welds, and thin-walled austenitic steel.
  • Detection of internal corrosion in structures susceptible to corrosion, such as pipes and tanks.
  • Measurement of wall thickness in ferrous and nonferrous castings, and checking nodularity in cast iron.
  • Ultrasonic thickness gauging for structural and electronic ceramic components.
  • Monitoring thickness of clad layers in cookware.
  • Detection of disbonds, impact damage, and ultrasonic thickness measurements in aerospace composites.
  • Ultrasonic Thickness Gauging for fiberglass applications, including storage tanks, pipes, and boat hulls.
  • UT is a versatile technology with applications in various industries.
  • Applications include manufacturing quality control, ensuring structural integrity, and railway safety checks.
  • Ultrasonic Testing is a cornerstone in material evaluation, ensuring safety, reliability, and quality across diverse industries.
  • Its non-destructive nature and high precision make it invaluable for material assessment. 


Q. What is the application of ultrasonics in non-destructive testing?

A: Ultrasonics in Non-destructive Testing involves using high-frequency sound waves to assess the integrity of materials without causing damage.

   It is applied to detect internal flaws, measure thickness, and ensure structural soundness in various industries.

Q. What materials can ultrasonic testing be used on?

A: Ultrasonic Testing is versatile and can be used on a wide range of materials, including metals (such as aluminum, steel, and titanium), alloys, ceramics, composites (like carbon fiber and glass fiber), fiberglass, glass, plastics, rubber, and even precious metals like gold.

 Q. What is ultrasonic testing of materials?

A: Ultrasonic Testing of Materials is a Non-destructive Testing Technique that involves sending high-frequency sound waves through a material to detect internal flaws, measure thickness, and assess the structural integrity of the material.

It is widely used in industries such as Aerospace Industry, automotive, oil and gas, and more.

 Q. On what type of materials or products can ultrasonic thickness be applied?

A: Ultrasonic Thickness Measurement can be applied to various materials and products, including but not limited to metal pipes, tanks, structures susceptible to corrosion, castings, ceramics, composites, fiberglass applications, glass products, and even precious metals like gold bullion bars.

Q. What is the UT material thickness?

A: UT material thickness refers to the measurement of the thickness of a material using Ultrasonic Testing (UT) equipment.

   This technique allows for the non-destructive assessment of material thickness in applications such as manufacturing, construction, and inspections in various industries

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Application Notes