Investigators: L. J. Swartzendruber, D. E. Mathews, L. H. Bennett, R. D. McMichael, G. E. Hicho

Technical Description:

In this project we are investigating the use of magnetic properties to characterize the mechanical properties of steel. Magnetic properties can be measured non-destructively, whereas direct mechanical measurements must be done destructively.

Technical Objectives:

• Develop sensors for measuring the magnetic properties of steel in various geometries.

• Use state-of-the-art analog to digital conversion and digital processing techniques to process sensor outputs.

• Collect experimental data on the magnetic and mechanical properties of a wide variety of commercial sheet steels and on low carbon steel as a function of thermomechanical treatment.

• Relate the magnetic properties of the steel to the microstructure using phenomenological and micromagnetic models.

Anticipated Outcome:

• More consistent production of large quantities of steel with well controlled and uniform mechanical properties.

• Reduction in the number of costly and time consuming mechanical tests required.

• Improved understanding of the relationship between the magnetic and mechanical properties of steel.

Accomplishments for FY 1995:

• Determined useful multi-parameter models for relating yield strength to magnetic properties in high strength-low alloy (HSLA) sheet steel.

• Determined useful multi-parameter models for relating yield strength to magnetic properties in ultra low carbon (ULC) and low carbon (LC) sheet steel.

Impacts and Technical Highlights:

• The mechanical and magnetic properties of a series of HSLA and ULC sheet steels, produced on a continuous annealing line simulator under a wide range of processing conditions, were determined in detail. These results were used to determine phenomenological models that used the magnetic properties to predict the mechanical properties. Models were found which, using only the magnetic properties, were better predictors of yield strength and ultimate tensile strength than the processing conditions.

• Portions of this project were carried out in cooperation with LTV Steel Company and Weirton Steel Corporation, who provided the sheet steel samples, and with the Industrial Materials Institute in Canada, who provided ultrasonically determined structure parameters for evaluation. Results have possible applications for measurement of mechanical properties on-line in a steel mill and for rapid determination of steel uniformity, thus improving quality and reducing production and testing costs.

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Last modified: Mon Jan 06 09:46:15 1997 Metallurgy Webmeister