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Title: Correlation Between Eddy Current Signal Noise and Peened Surface Roughness

Abstract

For advanced uses of eddy current (EC) NDE models in, e.g., model-assisted POD, there is a need to understand the origin of EC noise sources so that noise estimations can be made for a given set of inspection conditions, in addition to defect signal predictions. This paper focuses on the material-oriented noise sources that exhibit some universality when isolated from electrical and mechanical noises. Specifically, we report on experimental measurements that show explicit correlations between surface roughness and EC noise as seen in post-peen EC measurements of shot-peened roughness specimens. The samples are 3''-by-3'' Inconel 718 and Ti-6A1-4V blocks, pre-polished and shot-peened at Almen intensities ranging from a low of 4N to as high as 16A, created by smaller ({approx}350 {mu}m) and larger ({approx}1 mm) diameter zirconium oxide shots. Strong correlations are observed between the Almen intensities and the measured surface roughness. The EC noise correlates equally strongly with the Almen intensities for the superalloy specimens. The correlation for the Ti-alloy samples is only apparent at higher intensities, while being weak for lower intensities, indicating the grain noise dominance for smoother surfaces.

Authors:
; ; ;  [1]
  1. Center for NDE, Iowa State University, Ames, IA 50011 (United States)
Publication Date:
OSTI Identifier:
21054933
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 894; Journal Issue: 1; Conference: Conference on review of progress in quantitative nondestructive evaluation, Portland, OR (United States), 30 Jul - 4 Aug 2006; Other Information: DOI: 10.1063/1.2718103; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CORRELATIONS; DATA PROCESSING; DEFECTS; EDDY CURRENT TESTING; EDDY CURRENTS; INCONEL 718; NOISE; ROUGHNESS; SURFACES; ZIRCONIUM OXIDES

Citation Formats

Wendt, S. E., Hentscher, S. R., Raithel, D. C., and Nakagawa, N. Correlation Between Eddy Current Signal Noise and Peened Surface Roughness. United States: N. p., 2007. Web. doi:10.1063/1.2718103.
Wendt, S. E., Hentscher, S. R., Raithel, D. C., & Nakagawa, N. Correlation Between Eddy Current Signal Noise and Peened Surface Roughness. United States. doi:10.1063/1.2718103.
Wendt, S. E., Hentscher, S. R., Raithel, D. C., and Nakagawa, N. Wed . "Correlation Between Eddy Current Signal Noise and Peened Surface Roughness". United States. doi:10.1063/1.2718103.
@article{osti_21054933,
title = {Correlation Between Eddy Current Signal Noise and Peened Surface Roughness},
author = {Wendt, S. E. and Hentscher, S. R. and Raithel, D. C. and Nakagawa, N.},
abstractNote = {For advanced uses of eddy current (EC) NDE models in, e.g., model-assisted POD, there is a need to understand the origin of EC noise sources so that noise estimations can be made for a given set of inspection conditions, in addition to defect signal predictions. This paper focuses on the material-oriented noise sources that exhibit some universality when isolated from electrical and mechanical noises. Specifically, we report on experimental measurements that show explicit correlations between surface roughness and EC noise as seen in post-peen EC measurements of shot-peened roughness specimens. The samples are 3''-by-3'' Inconel 718 and Ti-6A1-4V blocks, pre-polished and shot-peened at Almen intensities ranging from a low of 4N to as high as 16A, created by smaller ({approx}350 {mu}m) and larger ({approx}1 mm) diameter zirconium oxide shots. Strong correlations are observed between the Almen intensities and the measured surface roughness. The EC noise correlates equally strongly with the Almen intensities for the superalloy specimens. The correlation for the Ti-alloy samples is only apparent at higher intensities, while being weak for lower intensities, indicating the grain noise dominance for smoother surfaces.},
doi = {10.1063/1.2718103},
journal = {AIP Conference Proceedings},
number = 1,
volume = 894,
place = {United States},
year = {Wed Mar 21 00:00:00 EDT 2007},
month = {Wed Mar 21 00:00:00 EDT 2007}
}