| ELECTRIC
RESISTANCE WELDED
PIPE ( ERW ) |
Gulf International
Pipe Industry LLC
uses the High frequency
electric resistance
welding process
to manufacture pipes
ranging in nominal
diameter from 219
mm (8,58 inch) to
610 mm (24 inch),
and in wall thickness
from 4,0mm (0,118
inch) to 25.4 mm
(1,00 inch).
Side trimming and
Edge milled steel
strip is mechanically
formed into pipe.
There are two break
down rolls to make
a round shape and
feed the strip into
cage forming stand.
After passing three
fin pass stand,
a high-frequency
electrical current
is applied to fuse
pipe skelp to form
a weld. Unlike the
arc-welding process
no filler material
is added. The weld
becomes a homogeneous
part of the completed
pipe. The welding
facilities are equipped
with diagnostic
system to control
and show the all
information of operating
such as cooling
water circulation,
input & output
voltage, power consumption,
and all the weld
parameters.
In order to ensure
completely smooth
pipes, welds are
trimmed both internally
and externally.
Immediate confirmation
of welds is assured
as pipes pass through
a multi-probe ultrasonic
inspection system
located after the
welding and trimming
stations.
Following ultrasonic
assessment, weld
joints are induction
heated to normalize
the metallic structure
of the weld. Seam
Normalising calls
“N”
process also improves
toughness of the
steel in the region
and significantly
decreases the weld
line corrosion effect.
After air cooling,
the pipe goes to
water cooling stand
to reduce the temperature
of weld seam. Prior
to hydrostatic testing,
pipes are sized
to required tolerances
before being cut
to length and the
ends beveled. Weld
seams are again
ultrasonically tested
for not only weld
seam but also full
body lamination
upon client requirements.
Pipes are inspected,
weighed and can
be varnished and
marked prior to
final inspection
and dispatch, or
transferred to the
coating plant to
continue FBE and
3 Layer PE/PP coating
for corrosion protection
treatment.
When required, pipe
is threaded and
coupled at the mill.
Couplings are automatically
made-up to position
with position/torque
capability. After
coupling make-up,
the pipe is transferred
to an automatic
drift station.
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