Nondestructive Detection of Tilted Planar Flaws on Back Surfaces Using Ultrasonic Wave Interference

Arai, Yasuhiko; Sato, Marie; Kawamoto, Daiki

doi:10.1299/jmmp.3.518

Cited by 1 publication

(2 citation statements)

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“…Before Fourier transformation, the echo signal was four times zero padded and windowed from the zero-crossing points of the derivative of the echo envelope (calculated using the Hilbert transform) to minimize the effect of the grain structure-induced scattering. The analyzed frequency range was windowed to the ultrasonic transducer's −20 dB bandwidth (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20).…”

Section: Signal Processing and Classificationmentioning

confidence: 99%

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Discriminating pores from inclusions in rolled steel by ultrasonic echo analysis

Kananen

Eskelinen

Hæggström

2011

Meas. Sci. Technol.

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The quality of steel is degraded by inclusions and pores which form during production. When exposed to external stress, large inclusions initiate cracks that weaken the mechanical strength of steel components. In this study, an ultrasonic immersion pulse-echo setup, which is currently used for quality control, was employed for signal-based inclusion and pore discrimination. The results from the used wavelet and short-time Fourier transform methods were verified with optical microscopy and scanning electron microscopy. The ultrasonic method was tested on 22 rolled bearing steel 100Cr6 samples featuring a total of 24 inclusions and 16 pores. Based on the differences in the echo peak frequency, it was possible to discriminate all pores from inclusions with the wavelet transform method. Sulfide and oxide inclusions also featured differences within the 9–14 MHz frequency range. The developed ultrasonic method was found to be capable of discriminating inclusions from pores in rolled bearing steel 100Cr6.

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Section: Signal Processing and Classificationmentioning

confidence: 99%

“…Ultrasonic non-destructive testing (NDT) employing an immersion pulse-echo setup is a potential method for flaw detection in steel [3,4]. The method provides an inclusion and pore count based on larger sampled volumes than the abovementioned common methods, thus potentially improving the quality control.…”

Section: Introductionmentioning

confidence: 99%