FIELD OF INVENTION:
The present invention relates to a method for low cost automation of support
trunion welding with stepped header of rotor post assembly. More particularly
the invention relates to automation in welding of support trunion by flux cored
are welding process.
BACKGROUND AND PRIOR ART OF THE INVENTION:-
In engineering many processes like machining, rolling, cutting welding are
employed. Of all the process welding is the only process which joins two
materials of same kind or different. Though welding looks simple it has got many
parameters like current, voltage, travel of torch, electrode fed in speed etc.,
need to be controlled to achieve the weldment with all the quality aspects set.
We deploy many welding process like Manual Metal Arc Welding, Flux Cored Arc
Welding, Sub-merged Arc Welding etc. The efficiency of the welding process
depends upon material deposition rate and quality of the welding produced.
Rotor post is one of the main components in the Air Pre Heater assembly. This
rotor post takes the full load of regenerative type Air Pre heater and rotated at 2
to 3 rpm. The load varies from 200T to 300T.

The rotor posts are exposed to corrosive atmosphere with temp more than
300°C. The weight of the rotor post is around 8T to 16T depends upon the size
of the Air Pre Heaters.
Rotor post is subjected to severe cyclic load and all the circumferential and
longitudinal joints are subjected to this load. Hence the quality of the weld
should pass through Magnetic Particle Inspection and Ultrasonic Tests. The
stepped header Vs trunion welding since it is subjected to major load should be
tested ultrasonically. The efficiency of the process shall be improved only by
increasing the metal deposition rate. In any welding process the cycle time
reduction can be achieved only by increasing the metal deposition.
Flux Cored Arc Welding(FCAW) process qualifies the requirements like higher
metal deposition rate, low heat input and flawless welding. Because of which
FCAW finds its place in "Weld Automation Industries".
The present field of invention is also development of one such semi automatic
weld automation for welding of Support trunnion and stepped header of rotor
post assy.
OBJECTS OF THE INVENTION:-
Therefore it is an object of the invention to propose a method for law cost
automation of support trunion welding with stepped header of rotor post

assembly which is capable of reducing time cycle and hence improves the
productivity.
Another object of the invention is to propose a method for law cost automation
of support trunion welding with stepped header of rotor post assembly, which
enables to achieve higher metal deposition rate.
Yet another object of the invention is to propose a method for law cost
automation of support trunion welding with stepped header of rotor post
assembly which is capable of reducing the Cost of operation.
A further object of the invention is to propose a method for law cost automation
of support trunion welding with stepped header of rotor post assembly which
makes the welding process automatic.
BRIEF DESCRIPTION OF THE ACCOMPAYNING DRAWINGS:-
Fig.l- Shows an arrangement of low cost automation welding of support trunion
with stepped header of rotor post assembly.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION:-
As shown in fig.1 groove welding of support trunion (8) with stepped header (9)
is done using the present invention. The device consists of rotating table(l)
carrying the support trunion (8) and driven by the gearbox(2) and motor (3)

arrangement to the speed required for welding. The Metal Insert Gas/Metal
Active Gas torch provided for groove welding as shown in fig.l uses CO2(7) or
mixture of CO2 and Argon gas as shielding medium and a standard power source
consists of wire feeding unit(5) with capacity to feed wire at the rate of 9.0 to
12.0 mtr/min and an invertor power source(6). Direct Current is used for the
rotating motor. Rotational speed of the motor is maintained equivalent to the
linear speed of the torch 40mm to 500mm/min. Wire feed in the torch is at the
rate of 9.00 to 12.00 mtrs/min. CO2 gas feed to the metal pool is at the rate of
16 to 20 Ipm. Amperage maintained at Power source 210 to 230Amps. Voltage
maintained in between 26 to 28 Volts. Low Cost automation for support trunion
welding involves the method of synchronizing rotating speed of the support
trunion, the wire feed rate and metal deposition rate to complete the welding by
flux core are welding.

We Claim:-
1. A method for law cost automation of support trunion welding with stepped
header of rotor post assembly comprising;
driving a rotating table(l) carrying the support trunion(8) by a gear box (2) and
motor(3) to suit the speed required for welding;
providing CO2(7) or a mixture of CO2 and Argon gas as shielding medium to a
metal inert gas/metal active gas torch(4);
supplying power by invertor power source(6);
feeding wire by wire feeding unit(5);
characterized in that the flux cored arc welding of support trunion (8) with
stepped header (9) is carried out by synchronizing rotating speed of the support
trunion (8), the wire feed rate and metal deposition rate.
2. A method of welding as claimed in claim 1, wherein the wire is fed by the wire
feeding unit(5) at the rate of atleast 9.0 to 12 mtr./min.
3. A method of welding as claimed in claim 1, wherein the rotational speed of the
motor is maintained equivalent to the linear speed of the torch (4) of atleast
400mm/min to 500 mm/min.

4. A method of welding as claimed in claim 1, wherein CO2 gas is fed to metal
pool at the rate of atleast 16 to 20 Ipm.
5. A method of welding as claimed in claim 1, wherein amperage maintained at
power source(6) is 210 to 230 amps and voltage is maintained in between 26 to
28 volts.

A method for low cost automation of support trunion welding with stepped header of rotor post assembly consists of driving a rotating table(l) carrying the support trunion(8) by a gear box (2) and motor (3) to suit the speed required for welding and providing CO2(7) or a mixture of CO2 and Argon gas as shielding
medium to a metal inert gas/metal active gas torch (4) when power is supplied by invertor power source (6) and wire is fed by wire feeding unit (5). The flux cored arc welding of support trunion(8) with stepped header is carried out by
synchronizing rotating speed of the support trunion (8), the wire feed rate and metal deposition rate.