FIELD OF THE INVENTION
The present invention relates to a method of holding Elbows and reducers for
conventional welding process. More particularly, the invention relates to a joining
of multi plane bend pipes called steam generator package links in supercritical
steam generators. The invention further relates to a device for fabrication of
steam generator package links of super critical high pressure boilers.
BACKGROUND OF THE INVENTION
A closed stationery installation for-transporting/distributing fluids like steak and
water in super critical boilers is called steam generators package links. These
steam generator package links are made up of high thickness pipes having
outside diameter 508 mm with thickness of mm. These pipes are having bends in
XZY (all three planes) position. These pipes are joined by SAW (sub Merged Arc
Welding) process. An auto welding of the rotor body only accepts straight pipes.
On the other hand, a manual welding requires the job or work piece to be
rotated for every layer of weld deposition, with help of a crane as the weight of
the job is 5500 Kg.
The time taken is normally 12 days to complete full welding. Moreover, the rust
and pores be formed on the surface during this period affects the quality of the
work and result in the rejection in the radiographic testing.

JP 2008249010 describes Seamless bend pipe and weld joint between seamless
bend pipe and seamless straight pipe and their manufacturing method.
This prior art invention describes a welded joint produced by welding and joining
the seamless bend pipe to a seamless straight pipe with the pipe and having the
same inner diameter on pipe end thereof.
The present invention is related to welding of seamless pipes in multi plane
having same diameter.
US 8112088 entitled "Method for repairing riser pipe elbow welding in boiling
water nuclear reactor" discloses a support clamp assembly for mechanically
securing a thermal sleeve to an elbow conduit in a jet pump of a nuclear reactor
vessel, the support clamp assembly including a tension shaft and an opposite
end with a head; a cruciform assembly to receive the tension shaft and seats in
the thermal sleeve seating on outside surface of the elbow conduit with a
coupling device places the tension shaft under tension.
Hence this more cycle time, more crane usage, more rework and above all
fatigue of the operator call for development of a device to hold the job so that
the job can be welded in SAW auto welding.

OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose a method of
welding elbows in auto welding machine which eliminates the draw back of the
prior art.
Another object of the invention is to propose a method of welding of super
critical boiler pipes having multi plane bend in auto welding machines.
A still another object of the invention is to propose a method of welding of super
critical boiler pipes having multi plane bend in auto welding machines which
includes more than one joints in the multi plane bends.
A further object of the invention is to propose a device to support welding of
super critical boiler pipes with multi plate bend.
SUMMALRY OF THE INVENTION
Accordingly, there is provided a method of joining bend pipes by SAW process
(Auto welding) by placing the bend pipes in the inventive device for easy holding
by a plurality of fasteners (bolts and nuts) and handling of the multi plane bend
(supercritical links) having outside diameter of 508mm with thickness of 70mm
weighing 5.5 MT. The work piece is placed on the horizontal pipe (01) which was

suitably cut at an angle of 60 degree to horizontal plane with a vertical curved
plate (07) to suit the elbow (10) diameter of the work piece and the job is
clamped with other clamps (03, 04) to arrest the movement of the other axes.
Now the job is ready for machine welding.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 shows an elbow including reducer in position in the inventive device.
Figure 2 shows a top view of Figure 1.
Figure 3 shows an isometric view of the inventive device without work piece in
position.
DETAILED DESCRIPTON OF A PREFERRED EMBODIMENT OF THE
INVENTION
According to the present invention, the auto welding is carried out by positioning
the work piece in the device with suitable clamps and adjustable screws at three
places. One clamp is in the vertical direction and two clamps are in the horizontal
direction. The whole assembly is attached to the rotor body of the welding
machine (not shown). As the rotor rotates, multi plane bend is carried out with
easy handling of the work piece without much effort.

Figure 1 shows the different parts of the device with elbow (10) and another wok
piece (11) which was already welded with a reducer (12). A horizontal pipe (01)
is having inclined opening for easy positioning of the work and the angle of taper
is made 60 degree to the horizontal. An inclined curved plate (07) is welded with
the horizontal pipe (01) to perfect seating of the net work piece (10) and its
clamped with semi circle clamps (08) and tightened with adjustable screws (09).
The other portion of the elbow is fixed with two circular clamps (03, 04) at a
distance of 500mm and these two clamps are also tightened with adjustable
screws (05 and 06) respectively.
The maximum outside diameter of the work piece is 508 mm and thickness of
the pipe is 70mm and these pipes are used as steam generator package links.
The horizontal pipe (01) is welded with two rectangular bars (02) on either side
of the pipe for fixing the semi circular clamps (03, 04) so as to use the
adjustable screws effectively.

WE CLAIM :
1. A method of welding multi plane bend pipes in auto welding machines,
comprising the steps of :
placing an elbow (10) in a horizontal pipe (01) which is having 60 degrees
slant opening to position the job with a curved plate (07) welded on the
bottom, including adjusting the job by adjustment screws (09) provided
on both sides;
- positioning the work piece along the horizontal directions by adjustable
screws (05,06) with semi circular clamps (03,04) respectively;
- fixing the outside diameter of the work piece perfectly on the horizontal
pipe (01) and welding rectangular bars (02) on each side of the work
piece.

2. The method as claimed in claim 1, wherein the semi circular clamps can
be varied according to the outside diameter of the elbow (10) and a
curved plate (12) for vertical position.
3. The method as claimed in claim 1, wherein the auto welding (7) for
straight joints achieves substantial reduction in cycle time of 96 hours to 8
hours.

4. A device for fabrication of steam generator package links of super critical
high pressure boilers by welding mult iplane bend pipe in an auto welding
machine, the device comprising :
a horizontal pipe (01) having tapered opening of 60 degree to horizontal
axis with a plurality of welded clamps (07) in horizontal direction and
curved clamps (12) in vertical direction;
at least one each rectangular bars (02) fixed on either side of the
horizontal pipe (01);
a plurality of semi circular clamp (08) with adjustable screws (09) in the
vertical direction;
a plurality of semi circular clamps (03, 04) with adjustable screws (05, 06)
disposed in the horizontal direction to arrest movement of the job along
XYZ directions;
and the device with the job fitted on the rotor body of the auto welding
machine to carry out welding of the job.

ABSTRACT

The invention relates to a method of welding multi plane bend in auto welding
machine. The invented device having horizontal pipe (01) having tapered
opening of 60 degree to the horizontal axis with welded clamps (07) and curved
clamps (12) in the vertical direction. The rectangular bars (02) fixed on the
either side of the horizontal pipe (01). All the XYZ movements one arrested by
the semi circular clamp (08) with adjustable screws (09) in the vertical direction,
where in the horizontal direction the semi circular clamps (03) and (04) are
positioned by adjustable screws (05) and (06) respectively. The work piece thus
made is ready for fitting in the rotor body of the auto welding machine to carry
out the SAW welding uniformly for the work piece having outside diameter
550mm with thickness of 70mm seamless pipe of having specification SA 335
P91 and SA 335 P12 and the weight of work piece is 5.5 tons/job.