Page 25 - ITAN Autumn 2012.indd

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ITAN • Autumn 2012 • www.itatube.org
ITAN
This model is very handy and useful for
process optimisation.
We cut across the section of the pipe at
inlet and we simulated different rolling
processes with different mill setups.
Comparing results of mathematical
model, simulation and practical trials
we found out the effectiveness of our
process control prediction method and
the confirmation of the positive result
expected.
Contact status analysis was our
guideline for investing different pass
designs on our rolls, but it was not
enough. To much close pass design
means good filling of the groove, but
the problem of the gap overfilling can
appear. For that we built a specific post
process output called “Total Equivalent
Plastic Strain” to predict and avoid
marks on pipe skin.
In the picture below (on the right) a
wrong pass design causes marks on
pipes due to overfilling. Of course,
with heavier wall thickness (on the
left) the same pass design produced
less evident marks because of higher
sectional stiffness of the rolled material.
At the end we are now able to simulate
all kinds of reduction process with this
simulation structure.
Structural Design for
Flexibility
Let’s now explain our concept of
Flexibility, just mentioned above.
Our lateral changeover system is
fully automatic and performs stand
changing in a few minutes. The stands
to be replaced are removed from the
mill by inserting the corresponding
new one simultaneously. This is an
example of the effort of Danieli Centro
Tube to produce more flexible and
smart equipment for the end users, well
knowing the importance of time saving
during the standard operation of tooling
changes and maintenance.
Flexibility means even the possibility to
apply DANIELI FRT™ on a wide range
of possible applications:
• Sizing Mill (from 4 to 16 stands)
• Stretch Reducing Mill (generally from
16 to 30 stands)
• Extracting Mill, with FQM™ Retained
Mandrel Mills (generally with 3
stands)
• Extracting-Sizing Mill, with FQM™
retained mandrel mills (from 4 to 14
stands)
• DANIELI FRT™ is also suitable for
Re-Sizing mill in heat treatment lines
Finally, for us Flexibility is the
standardisation of cartridges which can
be used both for even or uneven stands
just flipping 180° along the vertical
axis passing through the centreline;
this operation is performed easily by a
standard crane during handling in the
workshop.
With our Rolls Radial Position
Adjustment, available in all the stands,
we fit the customer needs, allowing the
customer to fine tune up the equipment
according to his will, and at the same
time reducing the inventory: only two
finishing stands are required for a given
finished outside diameter.
Brief Mechanical
Description
DANIELI FRT™ Extracting/Sizing
Mill/Stretch Reducing mill is made of
stands, each one composed by four
driven rolls, mounted in a stand.
A quick changeover device is provided
for side shifting type stands changeover
system.
DANIELI FRT™ simulation system for investigating material
behaviour during rolling
In blue the material during stand 1 biting in the simulations
FEM Simulation System results: Contact
status in three stands mill setup
Total Equivalent Plastic Strain for a wrong pass design. On the left, heavy wall thickness,
on the right, thin wall thickness. Yellow stripes along the pipe axis means possible marks on
the pipe skin