FIELD OF INVENTION
The present invention relates to a fixture for welding steam generator piping
component of as low as 219 mm outside diameter in automated submerged arc welding
machine.
BACKGROUND OF INVENTION
Circular seam welding of Links (Pressure Pipes) for Super critical boilers
with pipe butt joint is normally carried out with Shielded Metal Arc Welding (SMAW). The
drawbacks in the SMAW process is time consuming, and substantial amount of electrode
is wasted as the same is discarded there by making the process expensive. Further, the
discarded electrode contributes to environmental pollution. For carrying out manual
welding of OD 219mm pipe butt joint, it takes 20 hrs. / joint, with excess man power,
crane usage, energy for continuous pre-heating, surface grinding for NDT (Non
Destructive Testing) and probable manual welding errors which reflects in the
Radiographic test. This consumes more cycle time, more crane usage, unsafe working
environment, more rework, fatigue to operator. The pre heating is repeated twice in the
whenever restart the welding. Alternately, to avoid SMAW process, submerged arc
welding can be used but in the cases the diameter of 219 to 273 x 45 to 65mm thickness
pipe joints cannot be welded in Submerged Arc Welding machine due to limitations like,
clamping the pipe in the pipe positioner. The pipe positioner is designed for straight pipe

clamping with outside diameter more than 323mm only. In complication of this, it is
needed to develop a device to hold the job in the existing pipe positioner, so that the
smaller outer diameter jobs can also be welded in SAW (submerged arc welding) process
to eliminate the draw backs said in the SMAW process.
Prior Art:
Patents search has been made and found no similar patent available.
OBJECTS OF THE INVENTION
Therefore, it is an object of the invention to propose a fixture for welding
steam generator piping component of as low as 219 mm in automated submerged arc
welding machine, which is capable of holding the smaller outer diameter of pipe in the
range of 219 mm to 273 mm for welding in submerged arc welding machine.
SUMMARY OF THE INVENTION
The new developed attachment assembly/fixture consisting of two numbers
of side plates with holes drilled on it so that the side screws on either side can be
forwarded and reversed with the help of the handle provided at the one end. The side
plates are welded with solid block (09) on both sides. The bottom of the solid block is
welded with bottom strip (10) for holding the pipe with more grip to avoid slipping.

The four numbers of the new developed attachment are fixed to the existing
positioner assembly by inserting each assembly in such a way that it touched the holding
block of the existing positioner assembly. The handle is rotated on either side to lock the
side plate with the existing holding block.
Benefits in terms of,
Productivity: Improved the productivity from 20% to 100%
Cycle time reduced by 87% and savings = 6080 hrs / annum
The saving calculation is detailed below:
Man hour saving 16 hours / joint
38 joints for one boiler i.e. 38x16 = 608 hours / boilers
Annually, 10 boilers coming out from the shop i.e., 10x608=6080
hrs / annum.
Quality: At the mean time quality achieved by means of fine surface finish.
Flush grinding for NDT work and Re-work is totally avoided.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 Shows the existing positioner assembly elevation with two pipes in position
with welding.
Fig. 2 View A of Fig. 1 shows the developed device fixed with the existing pipe
positioner assembly for holding lower diameter pipes.
Fig. 3 Shows the assembly of developed device.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTION
According to the figure 2, the new developed attachment assembly/fixture
(07) consisting of two numbers of side plates (08) with holes drilled on it so that the side
screws (13) on either side can be forwarded and reversed with the help of the handle
(11) provided at the one end. The side plates are welded with solid block (09) on both
sides. The bottom of the solid block (09) is welded with bottom strip (10) for holding the
pipe with more grip to avoid slipping.
According to the Figure 1, referring to the View A, the four numbers of the
new developed attachment is fixed to the existing positioner assembly (03) by inserting
each assembly/fixture (07) in such a way that it touched the holding block (06) of the
existing positioner assembly (03). The handle (11) is rotated on either side to lock the
side plate (08) with the existing holding block (06). Now the left side work piece (02) is
fixed by rotating the stud (04) through the guide bush (05) so that the right side work
piece (01) can be welded.
By this arrangement, the outside pipe diameter as low as 219 mm can be
hold to carry out the welding in the SAW machine. The maximum outside diameter of the
pipe up to 273mm can be fixed in this developed assembly for welding the pipes in SAW
machine. The thickness of the pipes is ranging from 45 mm to 65mm depends on the
links required in the super critical boilers.

The developed device (07) design ensures the concentricity and arresting
degrees of freedom in all directions to perform the welding same as for the larger outside
diameter of the pipes greater than 273mm.
Thus the draw backs said in the SMAW process are totally eliminated for
the lower diameter pipes welding in the SAW process using the developed device.
In the manufacturing of links in the high pressure, high temperature boilers,
the larger diameter pipes having more than 273mm outside diameter can be welded in
the sub merged arc welding machine. The positioner assembly will not hold the lower
diameter pipes. Necessarily these lower dimeter pipes are welded with manual shielded
metal arc welding process. To avoid the draw backs in the SMAW process, the new
developed device attached in the existing positioner of SAW machine to carry out the
welding and thereby the cycle time is drastically reduced in such way that the average
time taken in SMAW process is 20 hours is now only 4 hours per joint for the same pipe
diameter.

WE CLAIM
1. A fixture for welding steam generator piping component of as low as 219 mm in
automated submerged arc welding machine, consisting of;
four members of newly designed fixtures (07) fixed to an existing positioner
assembly (03), the said fixture consisting;
two side plates (08) with holes drilled on it for making provisions of side screws
(13) on either side to actuate a forward and reversed movement by a handle (11)
attached to the screw (13), the said side plates (08) being welded on both sides
of a solid block (09);
a plurality of bottom strip (10) welded to the solid block (9) for holding the pipe
with more grip to avoid slipping;
wherein the inserted fixture (07) is configured in the existing positioner
assembly (03) to touch the holding block (06) when the handle (11) disposed on
either side for locking the side plate (08) with the existing holding block, wherein
a stud (04) is disposed to move through a guide bush (05) for fixing left side work
piece (O2) so that right side work piece is welded.