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Centro de Investigacion
Industrial Center for
Industrial Research FUDETEC, a
non-profit foundation created in Argentina nearly ten years ago by the
Techint group of companies, runs a Center for Industrial Research where
our work on NDT is performed. The final aim of our activities is the
improvement in industrial practices leading to higher standards of
productivity and product quality.
Because our
Center is located within the premises of SIDERCA, a seamless steel tube
manufacturing plant, our work in nondestructive testing has focused on the
inspection of steel tubes by magnetic flux leakage (MFL). The analysis of
this technique involved the numerical modeling of the leaked field, the
measurement of magnetic properties of various steels, laboratory and plant
measurements of signals generated by machined and natural flaws, a Monte
Carlo simulation of the probability of detection and of occurrence of
false alarms, and a model evaluation of the improvement of detection
effectiveness through the use of artificial neural networks to process the
signal. We also devoted considerable effort to the development of a robust
industrial system for digitizing and processing in real time the signals
from conventional MFL equipment.
Our laboratory includes a facility for the MFL testing of pipes and an immersion tank for ultrasonic inspection. We use the latter for the detection of macroinclusions in samples of continuous cast steel, for studying ultrasound attenuation, and for analyzing geometries in flaw detection in steel tube walls.
Center for Industrial Research
FUDETEC stands
for the Spanish words that denote the Foundation for Technological
Development, a non-profit organization that was created by a group of
companies belonging to a corporation that is active in steel, engineering,
construction, oil, and other related industrial activities. This set of
companies, collectively denoted as the Techint Organization, originated in
Argentina nearly half a century ago, but by growth and purchase have
spread over several countries, including Italy, Mexico, Venezuela and even
the United States.
Almost one
decade ago this corporation decided to create FUDETEC, the main purpose of
which is to run CINI, a Center for Industrial Research where, among other
activities, our nondestructive work is performed. The idea was to have an
instance where industrial problems could be examined by people not
directly involved in the manufacturing work, but in close contact with it.
Such people have both stronger scientific background and more time
available than those devoted to production, and are therefore in a better
position to develop a deeper understanding of manufacturing techniques and
of the performance of industrial products in service. The final aim of
such activities is the improvement in industrial practices leading to
higher standards of productivity and product quality.
Our Center is
located within the premises of SIDERCA, a seamless steel tube
manufacturing plant in Campana, some 50 miles Northwest of Buenos Aires,
Argentina, and because of that reason, we have focused our work in
nondestructive testing on the inspection of steel tubes. In more recent
times, two similar seamless tube manufacturing plants have been
incorporated to the Techint group: one is Dalmine, located near Bergamo,
in northern, Italy, and the other one is Tamsa, in Veracruz, Mexico. Thus,
the geographical area to which we have potential access spreads from
Argentina to North America and Europe. This implies a two-way relation
with these manufacturing plants: having access to their problems and
providing or implementing in them whatever technical improvement we may
develop.
Our methodology
is roughly the following: after a problem or issue is raised, a simplified
numerical model is formulated to provide guidelines and identify the
relevant variables and process parameters, and their interdependence.
Laboratory tests, performed either at CINI or outside facilities, are used
to determine material properties which are essential ingredients of the
models. More elaborate finite-element three-dimensional models are also
performed when detailed quantitative results are required. And validation
through laboratory and plant tests is the decisive criterion to judge the
final applicability of a proposed course of action. Plant implementation
is of course performed in a joint effort
Because flaw
detection by magnetic flux leakage (MFL) is widely used in nondestructive
evaluation of steel pipes, our major efforts have been devoted to this
technique. The main problem here is to ensure a high probability of
detection of flaws that exceed some specified critical value, while
minimizing productivity losses due to the inevitable presence of false
alarms. The analysis of this problem involved the numerical modeling of
the leaked magnetic field in the presence of defects, the measurement of
magnetic properties of various steels, laboratory and plant measurements
of signals generated by machined and natural flaws, a Monte Carlo
simulation of the probability of detection and of occurrence of false
alarms, and a model evaluation of the improvement of detection
effectiveness through the use of artificial neural networks to process the
signal. Because we aim at the implementation of this or alternative data
processing techniques in on-line inspection, we have devoted considerable
effort to the development of a robust industrial system for handling in
real time the digitized signals from existing conventional MFL equipment.
Such a system, developed in collaboration with Siderca's personnel, is now
operative in one of the existing Siderca lines, and has also been
installed in one of Tarnsa's lines.
We also share
with Siderca a laboratory where we have a facility for the MFL testing of
pipes and an inunersion tank for ultrasonic inspection. We have used the
latter for the detection of macroinclusions in the inspection of samples
of continuous cast steel, for studying ultrasound attenuation in steel and
for analyzing geometries in flaw detection in steel tube walls.
As a final
remark, it should be mentioned that it is rather uncommon for private
industries in Argentina to sponsor centralized R&D activities such as
those that we carry out at CINI. Even though our budget is still a
negligible fraction of the combined sales of the Techint group of
companies, it is steadily increasing, and by no means includes all the R&D
money spent by such companies. We expect our growth to continue to the
extent that we are able to provide answers to the demands that originate
in our industrial environment, which includes not only the companies that
created our foundation, but any other one willing to resort to us.
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