Page 26 - ITAN Autumn 2012.indd

26 ITAN • Autumn 2012 • www.itatube.org
ITAN
We can divide the main structure as
follows:
Frame for top Gear boxes and Motors
This consists of a welded steel structure,
designed to support the top gearboxes
and motors and to permit easy access
to the top drive group.
Roll Stands
The DANIELI FRT™ roll stand is a shell
type in two halves. Redressing of the
rolls is foreseen into a dedicated lathe,
which machines the rolls mounted in
the relevant stand. For each rolling unit,
two motorised systems are provided for
roll position adjustment by eccentrics
(one for two rolls).
The stands are provided with locking
pins placed on both sides of each stand
to align stands.
The stands are locked axially by means
of four cylinders cross disposed (two
north south NS, two east and west
EW) placed at the exit side of the fixed
structure. The two EW cylinders push
the pins in order to lock and align the
stands, while, the two NS cylinders
lock axially; all four cylinders (horizontal
and vertical) push the stand package
against the fixed structure on entry
side.
Stand Quick Changing System
(Side-Shift)
For the stand changeover a lateral
changeover system is foreseen: the
new stands are prepared onto a shifting
carriage at the charging side of the
mill in a position parallel to the stands
in the mill; when the change of the
rolls is required, the stands in the mill
are unlocked and the drives of the
rolls are disengaged. The new stands
are moved transversally to the rolling
centreline and they push the used
stands from the mill centreline onto
a lateral discharging shifting carriage
provided at the discharging side of the
mill.
The shifting carriages of the quick
changeover system have a movement
parallel to the mill centreline to transport
the stands out of the mill frame in order
to be carried out to the workshop by
crane.
Roll Adjustment Device
The roll adjustment device is made by
means of eccentrics systems for the
four rolls.
The eccentrics are driven by electric
motor and gear box; the adjustment of
the second roll is performed using a gear
that transmits the same adjustment.
The adjustment device can be rotated
out of the way of the stand by means of
a hydraulic cylinder in order to permit
the extraction of the stand.
Roll Drive Group
For each stand, two motors are
provided to drive the four rolls, through
two double output speed reducing gear
boxes, two reducers and by means of
coupling and spindles.
A gear box transmits power to spindles
oriented 90°.
Motor couplings: The motor torque is
transmitted to the gear box by floating
gear type couplings. This is done to
protect the drive elements.
Gear boxes: Each gear box is connected
to the relevant motor on one side and
has a slow output shaft connected
to the roll through the spindles. All
the gear boxes are connected to the
centralised oil lubrication system.
Spindle disconnecting and supporting:
The four spindles (telescopic type) are
equipped with four hydraulic cylinders
for engaging/disengaging.
When the stand has to be changed, the
cylinder allows the axial engagement
and disengagement of the spindles
from the relevant rolls. The back stroke
frees the way to allow the extraction.
Four supporting devices, consisting of
support wheels, are provided to support
the disconnected spindle.
Philosophy of
“Total Quality”
Quality is important and we proved we
can achieve it. But to keep it reliable is
very difficult.
We designed an automatic axial and
radial locking system for the cartridge
which keeps always perfect alignment
and robust locking during rolling,
creating a unique package of stands
compressed and aligned to each other.
Easy to understand for all, that is
the right way to have the deformation
process under control and tolerance
performances reliable.
Finally we can provide a lathe
machine which is able to machine
the rolls mounted on cartridge, to
avoid assembling problems during
reassembling operations; redressing of
rolls becomes automatic and does not
require special skills of the operators.
Two/three rolls technology…. The past
is away. DANIELI FRT™ is looking for
the future. But the future is today for
Danieli Centro Tube.
Fixed and Variable
Costs Saving
It is well known that especially for
sizing/stretch reducing mills, tooling
costs have to be considered in the
investment because it is not negligible.
The overall cost for a sizing/stretch
reducing mill can be mainly split in two
DANIELI FRT™
3D Full Scale
Prototype overview
Four Roll Cartridge Main Frame