TPi October 2009

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developmentsproducts &
32 Tube Products International October 2009
AMPCOMetal provideshigh-technology
alloys for demanding applications. The
company’s comprehensive range of
high-performance aluminium bronze
alloys for pressings, tube bending,
deep drawing, rolling and profiling
applications are readily available.
When producing stainless steel tubes
from strip, it is possible that the tube
surface can adhere to the roll surface,
(so called ‘cold welding’ or ‘galling’).
As the roll turns, such cold welding
causes damage to the surface of the
stainless steel tube, resulting in higher
rejection rates and lower productivity.
Additionally, when working with a semi-
circular forming roll in order to obtain a
tube out of a flat stainless steel strip,
any differences in tangential speeds
along the surface of the tube will induce
sliding between the forming roll and the
stainless steel sheet. Because of the
potential cold welding effect caused
by this difference in speed on the
forming rolls, the rolls must be made
from a material with excellent sliding
characteristics, in order to obtain a
perfect surface on the tubes.
Ampco Metal’s patented alloy Ampco®
25 offers multiple advantages, including
the extended life of forming rolls and
the quality of the finish to the stainless
steel tubes it produces. Ampco 25
alloy requires no further heat-treatment
or expensive coatings to give these
results.
Ampco 25 rolls are also used on the
same production lines at the tube
welding station, when producing
mild steel tubes. The non-magnetic
properties of Ampco 25 rolls at these
welding stations provides another
advantage, avoiding over-heating of
the pressure rolls, due to induction
from the high-frequency welding loop.
For bending stainless steel or other
tubular exhaust pipe materials, the
family of Ampco 18, Ampco 21 and
Ampco M4 alloys provide benefits for
product quality and prolonged life of
the production tooling. Ampco M4
used as mandrel and wiper dies in
tube bending have been proven to
last longer than commercial aluminium
bronzes. Ampco M4 mandrels do not
need hardening or expensive coatings,
and the advantages for wiper dies
are no galling or scratching, so no
corrosion starting point.
Ampco Metal SA – Switzerland
Copper alloys used to create
tubes with a smooth surface