Custom made bends - Bilfinger

Piping Systems
Bilfinger Piping Technologies GmbH
Bend geometry
Custom made bends from steel pipes have
a high accuracy of shape. Bending with
induction heat input is an advanced
procedure using a highly automated and
continuous forming process. During the
process the pipe will be pushed into a
narrow zone which is heated by a ring
shaped inductor. The bending force will be
applied axially to the pipe, the front end of
which is fixed in a swivel-arm. During the
bending process the bending arm will move
around its axis on a circular arc with the
specified radius. Through the applied axial
force the pipe follows the set circular path.
WALL THICKNESS
During the bending process the pipe
wall thickness at the bend extrados will
decrease, the same at the bend intrados
will increase. The percentage amount of
difference between the wall thickness of the
finished bend and that of the actual wall
thickness of the prepipe depends mainly on
the ratio of bending radius to pipe outside
diameter (R/D). The following chart gives
guidelines of the changes in the wall
thickness when using our bending
machines.
CHANGE OF WALL THICKNESS AT BENDING
% Increase % Reduction
20
10
0
10
20
30
40
50
max. reduction
min. increase
Air
Water
60
0
1 2
3 4 5 6 7 8 9 10 11
R/D ratio
12
Custom made bends