COMUNICAÇÃO TÉCNICA
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Nº 171773
Low-cost device for quantification of magnetic phases
Ramon Valls Martin
Trabalho apresentado no
Soft Magnetic Materials
Conference, 21.,SMM21,
Budapest, Hungary, 2013.
Abstract… IEEE
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Instituto de Pesquisas Tecnológicas do Estado de São Paulo
S/A - IPT
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www.ipt.br
Paper identification code (to be used by editors)
LOW-COST DEVICE FOR QUANTIFICATION OF MAGNETIC PHASES
Ramon V. Martin
Institute for Technological Research, Av. Prof. Almeida Prado 532, 05508-901 São Paulo, Brazil
The identification of magnetic phases in steel and other ferromagnetic materials can be done
reliably by measuring the magnetic polarization of saturation (Js) of small samples of the material.
When there is only two phases, and one is a paramagnetic austenitic phase, and another is a
magnetic martensitic phase or ferrite, the calculation of the volumetric contents is straightforward.
But, if there are three or more phases, then it is necessary to have distinct calibration points and to
know Js of each phase. These points can be provided by samples with previously measured
composition. Another approach to identify different phases is the measurement of the residual
induction (Br). These kinds of quantities are usually measured by bulky and high-cost equipment as
vibrating sample magnetometer (VSM). In order to measure Js and Br, we built a small device
based on the measurement of the magnetic moment by the extraction technique. The device can be
operated alone or in an ensemble of few of them. Also it is possible to get the induction at certain
field intensities (B25, B50, B100) assembling a device composed by several basic units with different
magnets, as that one shown in the figure below. The figure shows an aspect of the basic component
of the measurement system, where it is possible to see the pickup coils, the magnets, and the sample
holder.
We compared the results obtained from this method with the VSM and histeresigraph, using
samples of duplex steels and carbon steels. Despite the simplicity and low cost, the performance of
the device is comparable to large equipment, taking advantage of the portability and ease of
operation.
Name and e-mail of corresponding author:
Ramon Valls Martin - [email protected]
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