Using Eddy Current for Improper Heat Treatment Testing in Automotive Manufacturing

Automotive manufacturers need eddy current for improper heat treatment testing.

Defective automotive components are more common than many realize, which is why automakers need a quality nondestructive testing (NDT) regimen to eliminate improper heat treatment. Choosing techniques less favorable to NDT could result in defective parts that incur liability lawsuits or recalls. 

With that, advanced eddy current testing (ECT) instruments featuring simultaneous multi-frequency testing capabilities can help identify multiple material structure differences. This article will showcase why ECT is the best choice for automotive manufacturers conducting improper heat treatment testing.  

The Benefits of Eddy Current Testing in the Automotive Industry

Since heat-process variations are hard to detect visually, technicians need ECT equipment that can pinpoint deviations during the inspection process. Without eddy current, technicians are relegated to ineffective means like visual testing or cumbersome sample testing procedures that include cutting, polishing, and etching. 

Eddy current technology uses coils and magnetic fields to detect irregularities and isolate deviations. Eddy current allows analysts to spot all assembly flaws: delayed/short quenches, shallow case depths, misplaced cases, or short heats. Modern eddy current technology can confirm the quality of heat treatment faster than other NDT methods. Analysts can also achieve faster inspections and a repeatable testing strategy that allows operators to conduct in-line inspections of all manufactured components. 

However, eddy current testing is only as good as the device, and the eddy current equipment should include the following features:

  • Automated multi-frequency and multi-channel test set-up. 
  • Data recording capabilities.
  • Industrial I/O for easier integration with material handling systems.

A purpose-built eddy current instrument for manufacturing can be used to test for proper heat treatment on simple parts such as ball bearings and fasteners, as well as on complex components such as gears, wheel bearings and axles. With multi-frequency, multi-channel capabilities, it’s easy to simultaneously inspect for multiple anomalies at different locations on a single component.  

How to Use Eddy Current for Improper Heat Treatment Testing

With so many variables at play, the automotive industry needs eddy current testing on all parts on the assembly line. Eddy current can detect a variety of anomalies in the form of through depth, hardness and material mix testing.Also, eddy current readings can highlight the parts that haven’t been heat-treated. 

The automotive industry’s behemoth supply is more likely to produce untreated parts that could cause malfunctions and hazards. With eddy current, technicians can test for proper heat treatment on components such as rear axle cross pins wheel bearings and gears.

Example: In 2011, General Motors recalled over 26,000 cars due to real axle cross pins that were never heated. Cross pins without heat treatment are prone to displacement or fracturing, causing the rear axle to malfunction.

Take note of the following errors that could produce a substandard product:

  • Warped coil inductions
  • Tool misalignment
  • Condensation on parts

Importantly, analysts can test an item without destroying it physically. If a technician wanted to test the hardness of a valve tip, for example, they previously relied on batch testing, which involves destroying the parts that were recently hardened. Not only is destructive testing a waste of viable materials, but it also requires additional steps (i.e. visual inspection) that don’t always produce reliable data. 

On the other hand, eddy current will validate if the material is hardened without the need to destroy materials or look for defects with the naked eye. In fact, eddy currents can identify hundreds of defective valves in a row, allowing operators to stop production and further test items to enhance quality control. It will also confirm the correct structure in the material and assess the correct alloy compositions used during assembly. An eddy current system allows analysts to compare assets, ensuring that the tested item meets industry standards. 

Testing Improper Heat Treatment with Eddy Current Technology

To avoid improper heat treatment, technicians need an NDT system that can test items rapidly, reliably and with reproducible results. Eddy current can inspect more components than other testing systems, such as cluster testing. It’s also better than destructive testing and visual testing because both systems rely on the naked eye. 

With eddy current, the currents and magnetic fields spot all discontinuities within a part, and it can confirm if an asset has been heat-treated. Operators can continue operations with peace of mind and confirm whether the manufacturing process remains up to par. With an efficient workflow, automotive plants can prevent defective items that may degrade the durability of a car or cause dangers that jeopardize the lives of consumers.

Zetec is a major provider of eddy current equipment for the automotive industry. Contact us today to get a custom inspection plan and additional guidance on your NDT needs. 

Nondestructive Testing’s Biggest Advantages and Disadvantages

Nondestructive Testing's Biggest Advantages and Disadvantages

The concept of nondestructive testing (NDT) originated in the 18th century with the industrial revolution that enabled mass production of parts—and prompted the need for visual inspection of those parts. Over the decades NDT methods and technologies evolved and now include penetrants, magnetic particles, radiography, eddy current, and ultrasound for inspection and testing.

Digital technology has greatly enhanced the convenience and accuracy to NDT processes, particularly in the areas of eddy current (EC) and ultrasonic (UT) techniques. Eddy current is rapidly replacing liquid penetrant and magnetic particle testing as the preferred method in certain surface inspection applications. Ultrasound technology using advanced techniques like phased array and time of flight diffraction (TOFD) greatly improve inspectors’ ability to identify volumetric flaws or defects.  

Technical advancements are also significantly improving the efficiency and accuracy of NDT methods, especially in oil and gas, aerospace, power generation, and other industrial applications. If you’re finding that your current NDT methods are inadequate, take a few minutes to consider the biggest advantages and disadvantages of the latest technical improvements in NDT techniques and methods.

Nondestructive Testing’s Biggest Advantages

Although specific NDT advantages and disadvantages vary by industry and the types of inspections you conduct, we’ll focus on three areas that should be universally applicable—convenience, accuracy, and performance. Both individually and collectively, they offer compelling reasons to take advantage of the latest NDT capabilities, even when taking into account the inherent disadvantages involved in making that transition.

Greater Convenience in Conducting Inspections

Miniaturization characterizes much of the digital revolution. Smaller components with greater capabilities are manufactured more economically. The result? Devices are available with substantially better functionality and a smaller form factor than devices from a few years ago. Think smartphones, earbuds, and LED lights.

The same holds for NDT devices. Today’s eddy current and ultrasound devices have long-lasting, rechargeable batteries and are eminently portable. Many of these newer instruments are fully integrated and can handle an inspection from acquisition to analysis and reporting, without any external software or bulky equipment.The refined design and user interface of some handheld EC devices allow inspectors to easily hold the device in one hand and the probe in the other, greatly reducing fatigue and increasing the efficiency of any inspection. Portable UT devices can replace radiographic methods and eliminate the associated safety hazards and challenges including inspecting large, irregular shaped parts or difficult to access specimens.

Smaller form factor and intuitive user interface make these EC and UT devices far more convenient and adaptable to a wider range of inspection applications. These enhancements allow technicians and inspectors to:

  • Quickly set up equipment and conduct inspections, particularly in confined environments or remote locations.
  • Complete inspections and reporting faster, leading to reduced downtime.
  • Minimize interference with operations or personnel working in close proximity in factory, plant, or field locations.

Greater convenience and adaptability to a wider variety of inspection environments and situations is a significant nondestructive testing advantage enabled by smaller, portable NDT devices.

Increased Accuracy of Inspections

Advances in the EC and UT technologies enable far more accurate testing and inspection in comparison to other traditional NDT methods or earlier generations of EC and UT devices.

  • Improved signal-to-noise ratio (SNR) leads to better flaw detection.
  • Transducer improvements such as beam steering enable greater penetration of materials, detecting defects at greater depth.
  • Higher sensitivity uncovers minute flaws previously unrecognized by earlier generations of NDT hardware.

Each of these capabilities gives inspectors greater ability to detect flaws or defects, gain a more detailed understanding of the nature of the flaw, and do so far more efficiently in comparison to older methods or technologies.

Faster, More Powerful Performance

Smaller devices are the result of smaller components that deliver ever-increasing processing power. Greater processing power and the software that takes advantage of this capability are reasons enough to consider the advantages of the latest EC and UT devices. As an example, phased array technology with advanced examination techniques—as well as the ability to store, analyze and visualize volumes of data—allow inspectors to:

  • Create configuration profiles for frequently conducted tests and inspections, thereby reducing setup time.
  • Quickly interpret and diagnose defects using 3D visualization and analysis.
  • Easily share data and analysis with other subject matter experts to confirm findings.
  • Retain inspection data for future reference or as required by industry or government regulations.
  • Easily compare data from previous inspections to monitor conditions such as changes in crack size, corrosion, thickness, and delamination.
  • Automatically create and customize reports that include 3D images, data fields, and other vital inspection details.

The ability to gather, analyze, visualize, and retain greater volumes of inspection and testing data as well as efficiently monitoring changes over time facilitates easy comparison of sequential inspections. It provides greater detail and continuity in detecting, diagnosing, and monitoring defects.

Nondestructive Testing’s Biggest Disadvantages

Of course, any decision to make a change in strategy or processes is not without some challenges. Organizations that rely on well-established, low-cost NDT methods (like penetrants and magnetic particles) or have substantial investments in radiographic technology may find it hard to justify the investment in new NDT technologies.

In addition to hardware, you’ll need to consider training or certification of technicians. Alternatively, you may need to hire technicians with established skills to fill those gaps. Highly-regulated industries or companies with prescribed inspection codes will need to update procedures to ensure they comply with current regulations.

A multi-year cost-benefit analysis may provide a financial rationale for adopting the latest EC and UT technologies. Choosing instruments and software platforms that are easy to use with highly intuitive user interfaces will help reduce initial training costs. As a result, you’ll likely find that benefits outweigh any of the disadvantages. Greater accuracy, efficiency, and confidence in inspection results are worth the investment.

Reasons to Consider the Latest Nondestructive Testing Technologies

Improvements in NDT technologies should compel any organization with significant physical operational quality inspection or testing requirements to evaluate the latest developments in eddy current and ultrasound technologies. Improvements in portability allow technicians to conduct inspections in more locations with greater efficiency, leading to reduced downtime. Greater accuracy improves the probability of detecting material flaws and defects. Powerful performance enables inspectors to visualize and analyze data in greater detail, faster than before and supporting more confident inspection findings.

Zetec is a global leader in nondestructive testing (NDT) solutions for the critical inspection needs of industries. We are a single source for high-performance solutions in both eddy current and ultrasonic technologies that help clients ensure asset integrity and product quality. Contact us today to learn how Zetec delivers solutions that optimize productivity, safety, and total cost of ownership.