manufacturing process is completely automatic and has an optimum
capacity to produce 15000 metric tones per annum. The company is using
widely accepted high frequency induction resistance welding process under which
the current is made to flow through contract resistance to fuse the metals that
are held firming together by mechanical pressure.
process has so many advantages like :-
It is possible
to manufacture high polished tubes without any mark scratches or distortion on
the surface which is inherent with other manufacturing process using surface contacts.
Better welding is assured because the stitching effect which is inherent with
a lower frequency welding is eliminated. Steel tubes manufactured by this process
are most suitable for subsequent processing. With the high welding speed, heating
time is considerably reduced. Thus removing the risk of the structure of the metal
undergoing basic structural changes.
CR Coils are slitted
to predetermined widths for each size of tubes as per the outer diameter.
coil is uncoiled at the entry of ERW mill and the ends are sheared and welded
one after another to make it a single endless strip.
When slitted coil
is passed through the ERW tube mill then at the initial stage it is bended from
center and the coil obtains the U shape and then into a cylindrical shape with
open edges using a series of forming rolls.
The open edges
of the slitted coil are heated to the forging temperature through high frequency
low voltage high current and high frequency induction resistance welding process
under which the current is made to flow through contract resistance to fuse the
metals that are held firming together by mechanical pressure.
Weld flash on top
is trimmed out through carbide tools.
The steel tube
formed is passed from the cooling block so that at the last roles the accurate
shape can be formed. The final shape is given by the last roll sets.
Steel tubes are
cut to required lengths by flying cut off disc/saw cutter.