Welcome to another edition of our video
format EMG technology Nuggets. Today we are dealing with the question, in
which cases sample tests with the online material testing system EMG IMPOC
are useful and how they are performed in a test stand at EMG in Germany.
As a reminder: EMG IMPOC is a magnetic inductive measuring system for online
determination of tensile strength and yield strength. For that purpose firstly
the magnetic properties of ferromagnetic steels are measured. In a second step the
real material properties are the deduced from the magnetic values using suitable
mathematical modeling for example linear regression.
In the forefront of a new system installation sample testing at EMG in
Germany is generally not required. Today the system covers a wide range of steel
grades. This includes bake hardening and high-strength IF steels, micro alloyed and various multi-phase steels. Only for complex phases and high-strength steels
above 900 respectively 1000 mega pascals sample tests in the IMPOC test stand
are useful in individual cases. Sample testing is also required for strip
thicknesses outside the specification, that means more than 6 millimeters for
the PowerIMPOC system version. If sample tests shall be carried out at
EMG, the provided material samples must meet certain basic conditions which is
summarized here. One important note should not be forgotten: sample tests
with EMG IMPOC test stand relate exclusively to the measurement of the magnetic
properties of the material and do not allow any statement about the absolute
values for yield strength and tensile strength. This would require mathematical
modeling which requires a large number of destructive test results.
The following video shows how a sample analysis is performed in the test
stand at EMG. It allows to move the samples between the and the IMPOC heads on top
and bottom side at a speed of up to 600 meters per minute. During each
measurement the sample is first automatically demagnetized, so that the
measurement result is not distorted. In the second part of the video it is shown,
that for research and development purposes 3d measurements of the magnetic
field can also be carried out using a hall probe in the same test station. The result of a sample analysis for a
selected steel type is shown in this graph. It shows the relationship between
measured IMPOC values on the x-axis and the results of the destructive tests
for tensile strength on the y-axis. The example shows the very good correlation
between the magnetic values of the residual magnetic field strength in ampere per
square meter and the destructive test values for this material.
With about 70 installations worldwide IMPOC is the only industrially proven and
reliable measuring system for online material testing of flat steel. The
models available today cover a wide range of materials including the latest
generation of high-strength steels. The system is used at pickling lines, hot dip
galvanizing lines, annealing lines and increasingly at automotive lines.
EMG offers the necessary services, the transfer of know-how and all necessary
preliminary tests and consulting for all IMPOC projects.
So, in case that you are hungry for more information: don’t hesitate to visit us
in our headquarter in Germany or on our website, don’t forget to follow us on
YouTube and if you like this video please spend us your like also on
YouTube. Thank you very much and we hope to see you soon again!