FIELD OF THE INVENTION
The present invention relates to welding process applicable to high pressure
boilers, in particular a Flux Cored Arc-Welding (FCAW) process. More particularly,
the invention relates to an improved method of an improved flux cored arc-
welding process for forming water well panels.
BACKGROUND OF THE INVENTION
The water wall panel for all utility boilers is welded through manual process and
the productivity is not more than 0.5 m/min for panel forming by the Sub
merged Arc Welding (SAW) process. Further, the defects of following nature
developed during the welding process increases the rework. The defects are
generally in the nature of burn through, undercut, off line, excessive penetration,
porosity, distortion etc. this SAW process has limitation due to the above
reasons. The recent conversion of SAW process into MIG/MAG welding process
using 100% C02 % C02 + Argon Mixture as a shielding gas, is presently used
for water wall panel's formation.
OBJECTS OF THE INVENTION
It is therefore an object of the invention is to propose a flux-cored arc welding
process, which increases the productivity.
Another object of the invention is to propose a flux-cored arc welding process,
which uses 100% CO2 or CO2 + Argon Mixture, as the shield gas.

A still another of the invention is to propose a flux-cored arc welding process,
which is enabled to increase the welding speed by adapting a multi torch
arrangement.
Yet another of the invention is to propose a flux-cored arc welding process,
which is implemented in a Flux Cored Arc Welding (FCAW).
A further of the invention is to propose a flux-cored arc welding process, which
uses a thin metal strip of tubular wire containing flux inside is used.
A still further object of the invention is to propose a flux-cored arc welding
process, which uses a shielding gas such as carbon dioxide or argon + carbon
dioxide gas mixture.
Yet further of the invention is to propose a flux-cored arc welding process, which
is simple and easy to implement.
SUMMARY OF THE INVENTION
According to the invention, firstly, the welding current is being applied to a small
cross section of a metal wire and a forcible arc is applied through the CO2 shield,
which enables an increased welding penetration resulting in an increase in
welding speed. The welding speed up to 1.3 m/min is achieved in this process in
the down hand position leading to an enhanced productivity. The operators
ability to view the arc and elimination of use of a flux allows elimination of
defects in the weld, such as porosity, burn through, undercut and off line which

were common in the prior art process. The metal wire comprises a thin metal
strip of tubular wire having flux inside the wire. Further, the process uses a
multi-torch device for welding.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows the top view/general lay-out of a flux cored arc welding-
panel processing machine according to the invention.
Figure 2 - shows the front view/general lay-out of a flux cored arc welding-
panel processing machine of Figure-1.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 shows the top view of a flux cored arc welding-panel processing
machine to implement the inventive process. The machine comprises a welding
chamber (1), a tube pressing roller (2) an out feed conveyor (3) an in feed
conveyor (4) a return conveyor (5) and a tube with fins (6).
Figure 2 shows top view of the machine of Figure-1. The machine further
comprises a gas supply and distribution system (2), an wire feeder unit (3), an
welding torch assemblies (4), an welding wire inside a torch assembly and (5)
controllers (C).
The auxiliary and supporting equipment required for implementing inventive
process for a multi torch panel welding machine, comprises means for hot fumes
extraction, means for operator eye protection, and remote torch control devices.

Parameters:
PANEL WIDTH : 2500MM
TUBE DIA : 25.4 - 76.1 mm
WALL THICKNESS : 2.3 - 10 mm
FIN WIDTH : 10 - 110 mm
FIN THICKNESS : 4 - 12 mm
PANEL LENGTH : 4m - 25 m
FLOOR SPACE : 66.5 * 13 m
Before Conversion:
Welding wire : 1.6 - 4 mm
Avg. Welding speed/min : 200 - 500 mm
Power : 360 kw
No of Torches / SAW : 6
After Conversion:
Welding wire : 1.6 - 4 mm
Avg. Welding speed/min : 1200 - 1400 mm
Power : 360 kw
No of Torches /FCAW : 6

WE CLAIM
1. An improved Flux Cored Arc Welding process for forming water panels,
the improvement is characterized in that:
- applying an welding current to a small section of a metal wire to generate
a forcible arc being applied on the job through a shield gas, the shielding
gas constitutes one of 100% CO2 and a mixture of CO2 and argon gas;
- applying the forcible arc in combination with the metal wire under shield
gas protection enhancing the welding penetration;
- adapting a multi-torch device in the welding process;
- allowing a downhand-position welding by the operator resulting from
visibility of the arc in absence of flux addition during the welding process;
and
- the metal wire comprises a thin metal strip of tubular wire internally
accommodating the flux.

The present invention relates to a method of welding water wall panels using
flux cored wire that consists of a flux inside the core with a shielding gas of
carbon dioxide or argon + carbon dioxides gas mixture with multi torch
arrangement, which increased the welding penetration resulting in increasing
welding speed and up to 1.3 m/min is achieved in this process. This process is
having capability of increasing the welding arc and eliminating the use of flux
which leads to depictive joints and further allows substantial reduction in
consumables including the flux. The invention being free from flux and slag, it
maintains a cleaner environment for efficient working.