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How To Effectively Inspect Friction Stir Welds in Manufactured Components for the Aerospace Industry
By: Eddyfi Technologies
Source: Eddyfi Technologies
Friction stir welding is a solid-state joining process frequently used in the aerospace industry. Depending on manufacturing parameters such as rotation and translation speed, the friction stir welding process sometimes creates discontinuities within the weld; therefore, a non-destructive testing method must be applied to ascertain weld integrity. High productivity, efficiency, and accuracy are at the core of these mandatory assessments during the quality assurance stage of newly manufactured aircraft.

The Challenge

Friction stir welding has been known to pose certain inspection challenges when it comes to quality assurance checks. Conventional non-destructive testing techniques tend to be time consuming, unreliable, require setup and calibration of multiple probes, and often do not provide adequate coverage.

Select advanced phased array ultrasonic testing techniques have previously been considered for replacing conventional ultrasonic testing and radiographic testing of friction stir welds in newly manufactured aerospace components. However, the most common inspection method, based on phased array ultrasonic testing, has several limitations in terms of industrialization as well as performance and reliability. The frequently used inspection technique typically requires three different beam angles to detect flaws parallel to the weld center line. The standard inspection offering uses multiple probes and requires each probe be aligned and calibrated, making for a lengthy process. Reliability remains an issue as transverse or skewed flaw types are not reliably detected with a standard probe design. In addition, weld surface conditions and flashing can prevent adequate coverage of the weld area with contact solution. Therefore, industry seeks a more productive solution with trusted inspection results.

The Solution

A dedicated probe design implements multiple simultaneous inspection configurations, minimizing the time required for setup.

The challenges of inspecting friction stir welds have been answered with Eddyfi Technologiesí optimized probes and high-end phased array ultrasonic testing instruments with dedicated onboard software.

To assess the inspection configuration and associated detection performance, a standard 10 MHz 64-element probe was used to scan a friction stir weld sample with artificial indications that simulate realistic friction stir weld discontinuities. This enables a performance baseline to demonstrate the benefits and improvements that the new optimized design offers compared to standard commercially available solutions.

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