FIELD OF INVENTION
The invention generally relates to Strip-Electrode Gas Metal Arc Welding
(SEGMAW). More particularly, the invention relates to an improved welding torch
for "Strip-electrode Gas Metal Arc Welding". The invention further relates to an
improved strip electrode gas metal arc welding system.
BACKGROUND OF THE INVENTION
There has been a continuous demand for newer welding processes and
techniques with improved productivity, better quality in order to bring down the
cost of welding. It was demands such as these, which prompted the
development of high-performance welding processes with enhanced wire feed
speeds and deposition rates. A process is regarded as a "high-performance"
welding process if it achieves a deposition rate more than 8 kg/h.
"Tandem" MIG welding is one such high performance MIG welding technique
developed to achieve higher productivity. It involves feeding of two electrode
wires through the same torch, creating two arcs acting on the same weld pool
and melting off simultaneously. Though tandem MIG gives higher deposition rate
and welding speed, there are problems with guiding the torch along curved
welding seams, as the geometrical relative positions of the leading and trailing
wires have to be maintained with respect to the direction of welding.
A new approach to boost the performance of GMA welding is to use flat strip-
wires, with which higher deposition rates comparable to that of tandem MIG can
be achieved. The advantages of strip electrode GMA welding over tandem

welding are, firstly, that only one power source is needed, and secondly, it is
considerably easier to set the welding parameters.
Strip-wire electrodes are produced either by additional rolling of round wires, or
by slitting wide strips. Rolled strip-wires have rounded edges, while slit strip-
wires tend to be sharp-edged. From the wire feed point of view, then, rolled
strip-wires are preferable.
However, winding the strip electrode on standard welding spool is quite difficult
and feeding of the strip-wire electrode causes problems due to twisting of strips.
Therefore, it would be desirable if the standard MIG welding wire is converted
into continuous strip online and is fed through an improved welding torch. Such
a development shall eliminate the need for winding the strip wire on the spool.
An improved torch must be capable for feeding strip electrode. Additionally, it
will be necessary to develop a corresponding gun and contact tip for
accommodating the strip electrode wire.
OBJECTS OF THE INVENTION
It is therefore an object of the invention to propose an improved welding torch
capable of accommodating strip electrode wire, which eliminates the
disadvantages in prior art strip - electrode gas metal arc welding technique.
Another object of the invention is to propose an improved welding torch, which is
capable for consistent transfer of the current to the strip electrode wire.

A further object of the invention is to propose a strip electrode gas metal arc
welding system which is capable of converting online the MIG welding wire to
continuous strip for feeding into the improved welding torch.
These and other objects and advantages of the invention will be apparent from
the ensuing description.
At the outset of the description, which follows, it is to be understood that the
ensuing description only illustrates a particular form of this invention. However,
such a particular form is only an exemplary embodiment and the teachings of the
invention are not intended to be taken restrictively.
SUMMARY OF THE INVENTION
Accordingly, in a first aspect of the invention there is provided an improved strip
electrode gas metal arc welding system for providing higher deposition rate,
improved gap bridging capability, higher welding speed and better weld quality,
the improvement is characterized by comprising; a guide tube for feeding a
standard MIG welding wire; a rolling - cum - feeding means for converting the
standard MIG welding wire to a flat strip being fed through an improved torch via
a contact tube; and a constant voltage type power source with reverse polarity
connection.
In a second aspect of the invention, there is provided an improved torch
adaptable in a strip electrode gas metal arc welding system, comprising; a torch
body for guiding the gas flow, the body housing at least two strip-wire guide
tubes, a gas cup being screwably attached to the torch body; a contact tip holder

including a contact tip cap and split contact caps, the contact tip cap allowing
feeding of the strip electrode, a stable arc being produced to provide a good
weld beat with higher deposition rate at a higher welding speed.
In a second aspect of the invention, there is provided an improved torch
adaptable in a strip electrode gas metal arc welding system, comprising; a torch
body for guiding the gas flow, the body housing at least two strip-wire guide
tubes, a gas cup being screwably attached to the torch body; a contact tip holder
including a contact tip cap and split contact caps, the contact tip cap allowing
feeding of the strip electrode, a stable arc being produced to provide a good
weld beat with higher deposition rate at a higher welding speed.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows an embodiment of the apparatus according to the invention.
Figure 2 - shows an improved welding torch according to the invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
Referring now to the drawings, wherein like reference numerals designate
identical or corresponding parts throughout the several views.
Fig1 shows the schematic of the Strip Electrode Gas Metal Arc Welding system.
In this system, a standard MIG welding wire (1) available in 300 mm diameter

spool (2) is fed through a guide tube (3) and then it is converted into a flat strip
(4) by a rolling cum feeding means (5). The flat strip (4) thus formed is fed
through a torch (6). The torch (6) incorporates a contact tube (7) to allow
feeding of the strip electrode (4). A standard Constant Voltage type power
source (8) is used with reverse polarity connection.
The welding system converts a standard 1.6 mm diameter MIG wire into a flat
strip (4) and feeds the strip (4) through the torch (6). A contact tube (7) has
been configured to allow feeding of strip electrode (4).
As shown in fig - 2, the welding torch of the invention comprises a torch body
(11) which houses atleast two strip-wire guide tubes (10, 13), and having a
contact tip holder (14), a contact tip cap (15) and a split contact tips (16). A gas
cup (12) is screwed on to the body (11) for guiding the gas flow. The shielding
gas is supplied through an inlet nipple (9) of the torch (6).
The advantages of the invention can be seen, inter alia, in the fact that the strip
electrode wire (4) is fed smoothly through the modified contact tube (15) and a
stable arc is produced resulting in good weld bead at higher welding speed and
deposition rate. The novel system provides higher deposition rate, improved gap
bridging capability, higher welding speed and better weld quality.

WE CLAIM
1. An improved strip electrode gas metal arc welding system for providing
higher deposition rate, improved gap bridging capability, higher welding
speed and better weld quality, the improvement is characterized by
comprising;
- a guide tube (3) for feeding a standard MIG welding wire (1);
- a rolling - cum - feeding means (5) for converting the standard
MIG welding wire (1) to a flat strip (4), being fed through an
improved torch (6) via a contact tube (7); and
- a constant voltage type power source (8) with reverse polarity
connection.
2. An improved torch adaptable in a strip electrode gas metal arc welding
system, comprising;
- a torch body (11) for guiding the gas flow, the body (11) housing
at least two strip-wire guide tubes (10, 13), a gas cup (12) being
screwably attached to the torch body (11);

- a contact tip holder (14) including a contact tip cap (15) and split
contact caps (16), the contact tip cap (15) allowing feeding of the
strip electrode (4), a stable arc being produced to provide a good
weld beat with higher deposition rate at a higher welding speed.
3. An improved strip electrode gas metal arc welding system for providing
higher deposition rate, improved gap bridging capability, higher welding
speed and better weld quality, as substantially described and illustrated
herein with reference to the accompanying drawings.
4. An improved torch adaptable in a strip electrode gas metal arc welding
system, as substantially described and illustrated herein with reference to
the accompanying drawings.

This invention relates to an improved strip electrode gas metal arc welding system for providing higher deposition rate, improved gap bridging capability, higher welding speed and better weld quality. A guide tube (3) for feeding a standard MIG welding wire (1); a rolling - cum - feeding means (5) for
converting the standard MIG welding wire (1) to a flat strip (4), being fed through an improved torch (6) via a contact tube (7); and a constant voltage type power source (8) with reverse polarity connection.