BC Material Testing and Validation: Ultrasonic Testing (UT)

Posted on March 14, 2023 by Boston Centerless

Material testing and validation are essential aspects of manufacturing. There is always the potential for material integrity issues, defects, or human error during production – and testing is the checkpoint to catch these problems. The use of testing to identify and resolve quality issues is critical to the performance, functionality, integrity, and reliability of the final product – and is crucial to maintaining your brand reputation. The time and effort required to test materials are well worth it.

One way precision machine shops ensure the quality assurance of products is with a robust testing and validation program. A common method used to confirm material integrity is Non-Destructive Testing (NDT). NDT covers a wide range of inspection techniques that are used across a variety of industries – all of which allow inspectors to assess the structural integrity of a material without damaging it. The purpose of non-destructive testing is to identify potential issues on the surface or within the material that may result in performance problems including failure. These tests are able to identify potential density or porosity issues as well as tiny cracks or gaps that could lead to integrity problems.

There are several different NDT techniques that vary in the level of time, equipment, and cost required to perform the test. Common NDTs for material testing and validation include ultrasonic, eddy current, magnetic particle, and x-ray technologies. Ultrasonic testing (UT) is one of the most prevalent practices and provides high quality results quickly without much setup required. The following explores the details and benefits of Ultrasonic Testing (UT) of materials.

It should be noted that comprehensive material testing is becoming more crucial as functionality and reliability demands increase for products in the field, especially in sensitive industries such as the medical and aerospace sectors. For this reason, it is important that companies partner with a proven precision machining shop, like Boston Centerless, that has an outstanding material testing and validation program – and that stands behind their products. At Boston Centerless, we are able to perform all testing and validation services in-house. This is a huge advantage for our customers as we avoid significant time and money spent on the transport of products to a 3^rd party location for these services – enabling our team to deliver unmatched lead times. Additionally, because we perform testing in-house, Boston Centerless is able to perform 100% product testing as opposed to testing a small sample size. This is another significant benefit for our customers, especially those that supply critical products to industries like the medical and aerospace sectors where failure in the field is not an option. Our ability to test 100% of our products gives customers a level of quality assurance that other suppliers simply cannot deliver.

Ultrasonic Testing (UT) 101

As noted above, non-destructive testing methods, like UT, do not damage or compromise the material. UT sends high-frequency sound waves through a material to identify any defects or flaws that may be present, and to determine the thickness of the material in the case of corrosion inspections. UT is ideally used for analysis of dense, crystalline structures like metals that conduct sound waves in a manner conducive to this form of testing.

During UT, a technician uses a probe or some form of transducer to send sound waves through the test material. If there are no defects or flaws present, the sound waves will pass through the material consistently; however, if defects are present, the sound waves will bounce off of the flaw resulting in inconsistent sound wave travel. The results of UT are often used to create a 3-dimensional graphic of the material to visually depict where the flaws are located.

There are several benefits of UT for precision machine shops and customers. First and foremost, with NDT methods, the material being inspected is not damaged or compromised by the testing – avoiding costly replacement or repair costs. UT delivers reliable results immediately. In comparison to other testing methods, UT is known for its accuracy, high sensitivity and penetration power, and ability to estimate the size, shape, depth, and nature of any defects detected. UT processes are easily automated and can be used with a wide range of geometries. Simply put, machine shops and OEMs can rely on UT inspections for precise material analysis.

There are two primary methods for UT: through transmission and pulse echo. Through transmission utilizes two transducers, one on each end of the material being tested. One transducer generates an ultrasonic wave and the other receives it. Imperfections in the material reduce the volume of waves that is received, allowing any flaws to be detected.

While both are excellent UT methods, the pulse echo method is typically more sensitive than the through transmission technique. With pulse echo testing, the same transducer emits and receives the sound wave energy. This method uses echo signals at an interface, such as the back of the test object, to reflect the waves back to the probe, measuring the time it takes the waves to return. Variances in the return time of the waves identifies any inconsistencies or defects in the material.

UT technologies have continued to advance over time, and today’s equipment is typically portable. Technicians are able to perform the inspection, analysis of the data, and report the results autonomously without the need for additional software or equipment. This advancement provides more timely results and gives real-time feedback to machine shop operators – yielding a more cost-effective solution compared to prior NDT generations.

Are you interested in the quality assurance and risk reduction that ultrasonic testing provides?

Contact Boston Centerless to learn more about our material testing and validation services including UT.

Boston Centerless Material Testing and Validation

One of the areas that sets Boston Centerless apart from the competition is our material testing and validation service. We are Nadcap^TM certified, which confirms to our customers’ that our UT process is sound and delivers trusted results. Additionally, Boston Centerless is investing in additional material testing equipment so in the near future we will be able to perform in-house testing of mechanical strength, elongation, and hardness. By performing these tests in-house and avoiding shipping, we can further drive down costs and enable even faster delivery times for our customers.

Integrity and certification of bar material is extremely important to mitigate risk. In order to gain the ability to verify the integrity of each and every precision bar product manufactured by Boston Centerless, our team has invested in equipment that tests for internal defects, surface defects, alloy verification and performs laser marking of the bar with customer-provided identifiers. Each of these capabilities can be provided in any combination based on the requirements of the customer. BC offers the following testing and validation services for round bar:

Ultrasonic Testing (UT)
- Round bar from approximately .180” diameter to a maximum of 1.000+0” diameter
- UT test standards including AMS-STD-215 Class A and Class AA
- Detects internal defects to within approximately 1 mm of the surface
- Automated re-direct of rejected bars to a separate collection bed

Eddy Current Testing
- Detects surface defects in bar products
- Adheres to ASTM E309, 571, E426, 576 (OD Solid Bar) test standards
XRF Alloy Verification Analyzer
- X-Ray analysis to detect non-conforming chemistry
- Pass/fail test for alloy verification
- Automatic identification and capture of rejected bars
Laser Line Marking
- Diameter Range of 0.090” to 3” dia.
- Standard Font Height of 1 mm to 1.5 mm with custom fonts available.
- Laser marking typically applied to the drop-end of the bar; can be used as Lot Retain Sample for material traceability

About Boston Centerless

Boston Centerless provides solutions that enhance our customer’s manufacturing processes. With over 65 years of experience with precision machining, we grind the tightest tolerances in the industry. When we were established, we were primarily a centerless grinding company, and over time we expanded our offerings to include manufacturing and distribution of precision raw materials and material preparation services.

We are a fully integrated product and service provider that can assist you with material selection, procurement, grinding, material testing and validation, customized inventory programs and supply chain management. Since we can procure and grind your material, we serve as your “one-stop shop” – saving time and money, and reducing risk, across your supply chain. We have proven experience with an extensive range of materials, and our manufacturing solutions include:

Contact us today at (781) 994-5000 to see how we can help with your next precision machining project, or click here for a quote.

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