Eddy current measurements on case hardened steel

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Sun, H.
Johnson, M. J.
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AIP Publishing
Bowler, John
Professor Emeritus
Bowler, Nicola
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Materials Science and Engineering

The Department of Materials Science and Engineering teaches the composition, microstructure, and processing of materials as well as their properties, uses, and performance. These fields of research utilize technologies in metals, ceramics, polymers, composites, and electronic materials.

The Department of Materials Science and Engineering was formed in 1975 from the merger of the Department of Ceramics Engineering and the Department of Metallurgical Engineering.

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Center for Nondestructive Evaluation

The Center for Nondestructive Evaluation at Iowa State has been involved in the use of nondestructive evaluation testing (NDT) technologies to: assess the integrity of a substance, material or structure; assess the criticality of any flaws, and to predict the object’s remaining serviceability. NDT technologies used include ultrasonics and acoustic emissions, electromagnetic technologies, computer tomography, thermal imaging, and others.

In October of 1985 the CNDE was approved by the State Board of Regents after it had received a grant from the National Science Foundation (NSF) as an Industry/University Cooperative Research Center.

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Electrical and Computer Engineering

The Department of Electrical and Computer Engineering (ECpE) contains two focuses. The focus on Electrical Engineering teaches students in the fields of control systems, electromagnetics and non-destructive evaluation, microelectronics, electric power & energy systems, and the like. The Computer Engineering focus teaches in the fields of software systems, embedded systems, networking, information security, computer architecture, etc.

The Department of Electrical Engineering was formed in 1909 from the division of the Department of Physics and Electrical Engineering. In 1985 its name changed to Department of Electrical Engineering and Computer Engineering. In 1995 it became the Department of Electrical and Computer Engineering.

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  • Department of Electrical Engineering (1909-1985)
  • Department of Electrical Engineering and Computer Engineering (1985-1995)

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The case-hardening process modifies the near-surface permeability and conductivity of steel, as can be observed through changes in eddy current probe signals measured over a range of frequency. In this work, experiments have been performed using normal absolute probe coils on flat steel specimens and coils encircling case-hardened steel rods. By fitting model results to the experimental data, estimates of electrical material properties are found. The approach also allows an assessment of the sensitivity of the measurements to the case depth.
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Sun, H., J. R. Bowler, N. Bowler, and M. J. Johnson. "Eddy current measurements on case hardened steel." In AIP Conference Proceedings, vol. 615, no. 1, pp. 1561-1568. American Institute of Physics, 2002, and may be found at DOI: 10.1063/1.1472979. Copyright 2002 American Institute of Physics. Posted with permission.