Page 24 - ITAN Autumn 2012.indd

24 ITAN • Autumn 2012 • www.itatube.org
ITAN
Market trends in pipe production are
swinging towards smaller and smaller
production batches with a move
towards production of hundreds of
tonnes instead of thousands. Requests
for very high production mixes however,
remain unvaried.
Danieli’s policy has always followed the
principle that requests from end users
are for smarter, more sophisticated
and more flexible solutions. Studies
are geared towards offering clients
innovative plant arrangements and
equipment technologies which are easy
to use but also aimed at reducing
production costs and time.
Flexibility is the basic line which was
driving Danieli Engineers team, but this
is not the only target through which
Danieli Centro Tube developed this
project.
The other point is the new design
philosophy of Danieli Centro Tube
FRT™, according to the idea of “Total
Quality”. This concept gives rigid rules
about the way to lead a project.
DANIELI FRT™ – The four roll
technology: new boundaries for
hot rolling OD finishing
Ing. Fabio Lacapruccia, Sales Manager DCT, Danieli Centro Tube, Italy
For us “Total Quality” is the only way
to achieve the best results, mainly
focusing of the high quality level of
products and process. Our belief is
that the final quality of the product
pass through the entire mill plant flow.
Because of that, each equipment we
provide customers is deeply studied,
taking care of each detail.
DANIELI FRT™ is one of the best
examples of Danieli’s way to work with
high synergy between departments to
have smart design focused on quality.
The Physics
The physical principle on which the
equipment is working is as effective as
easy to be understood.
While in the old two and three roll
technologies for Outside Diameter
finishing the trend of the rolled material
is to spread out on the roll groove; with
DANIELI FRT™ (Four Roll Technology)
the material natural trend is to collapse
in, achieving our main purpose that is
the Outside Diameter reduction. This
principle brings several conclusions.
One direct conclusion, very easy to
be understood, is to achieve a higher
reduction per stand or, on the other
side, higher stretches among stands.
Another direct conclusion is that the
wall thickness variation we produce
while we are reducing diameter is more
predictable and, for this reason, easier
to be kept under control. The uniformity
of wall thickness distribution across the
axis leads to a better tolerance of wall
thickness on the green pipe.
Regarding internal polygonisation
effects, both two and three rolls
technology needs oval pass designs
with high energy consumption. The
total amount of power absorption is
due basically by two terms: “Natural
Reduction Energy” and “Ovalisation
Energy ” . The second term (“Ovalisation
Energy ”) is less in Four Roll Technology
(FRT) process, because the pass
design is less oval and is focused
on our main target that is to produce
a perfect circle. So the deformation
energy is better spent to have higher
deformation efficiency.
This new kind of pass design reduces
the Outside Diameter tolerances
because it is much closer to the final
result since the first stand, and causes
less roll wear because the peripheral
speed is more uniform. It means that
there are reduced speed differences
between side areas and bottom gorge
areas.
FEM Simulation
Analysis System
for Technological
Optimisation
To develop and to fine tune up the
new equipment, we built up a new
simulation system with FEM analysis.
DANIELI FRT™ Full Scale
Prototype, Danieli CRD,
Buttrio (UD), Italy