Page 17 - ITAtube-journal_2-13

Large pipes, such as those used
to construct pipelines, are either
welded together with a spiral seam
or with a longitudinal seam. In co-
operation with the Swiss company
Maurer Magnetic, the plant and ma-
chinery manufacturer Schuler has
now developed a process which can
already demagnetize large pipes
during their production. This pre-
vents deflection of the arc during
welding and ensures the quality of
the welds, thus enabling them to
withstand the guaranteed loads.
“Magnetization can result on the
one hand from the rolling, machin-
ing, forming and plasma cutting
of steel sheets and on the other
hand from the submerged welding
of pipes with spiral or longitudinal
seams,” explains Dietmar Rieser,
Managing Director of Schuler ATIS.
“When pipe ends are then welded
together on site, the arc can be
deflected if there is too much re-
sidual magnetism – thus reducing
the quality of the weld. This is not
the case with demagnetized large
pipes.” Moreover, it avoids disrup-
tive influences during the quality
control process – e.g. when x-ray-
ing. Recent research results also
indicate an increased incidence of
corrosion on pipes which have not
been demagnetized.
“Pipelines are exposed to extreme
loads, as they often have to span
hundreds of kilometers of inhospi-
table territory with extreme tem-
peratures,” adds Schuler Managing
Director Jochen Früh. At the same
time, the transport pressure of me-
dia such as oil, gas or drinking wa-
ter inside the pipes is constantly
being raised in order to extend the
range and bridge the growing dis-
tances between individual extrac-
tion areas.
No delay in production
In the process developed by Mau-
rer Magnetic and Schuler, pipes
with spiral or longitudinal seams
are transported through an electro-
magnetic coil and demagnetized.
“There is no delay at all in produc-
tion,” assures Marek Rohner, Head
of Technology at Maurer Magnetic.
“We have therefore patented this
innovative process.”
Intensive tests at Schuler’s site
in Weingarten have shown that
the method is suitable for spirally
welded pipes with a wall thickness
of up to 25.4 millimeters and a di-
ameter of 20 to 120 inches. Pipes
with longitudinal welds can have
diameters of 16 to 64 inches and
a wall thickness of up to 80 milli-
meters.
Maurer Magnetic’s experts also use
their patented “Maurer Degaussing
Technology” for the process. The
large pipes are completely demag-
netized by an alternating magnet-
ic field, which can reach a field
strength of up to 80 kA/m in the
high-performance coils. The pro-
cess can also be used for rectangu-
lar, ERW and seamless pipes.
17
ITAtube Journal No2/September 2013
Companies
More stable pipelines for oil,
gas and water
Schuler developing new process for demagnetizing large pipes together with Maurer Magnetic
Demagnetizing pipes ensures the
quality of welds and enables them
to withstand high loads.
©Schuler
Meet us at
Tubotech Brazil 2013
Hall 01, booth 633