Title of Invention	AN IMPROVED METHOD FOR HARDFACING MARTENSTIC STAINLESS STEEL CARRIED OUT BY SUBMERGED ARC WELDING (SAW) TECHNIQUE
Abstract	Thus the invention is directed to a further development that the dissimilar wire combination is fed using a single wire feeder with a single nozzle drawing power from a single power source with parameters of 425 A, 28 V and 0.5 m/min as welding speed. A single weld pool is created in which the required weld chemistry are achieved by the use of two wires of different composition. This results in savings in consumables, cost and time. Accordingly to the present invention, the submerged arc welding wires ER430 of diameter 2.4 mm is used to deposit as buffer layer over the deposit finally hardfacing is carried out using the wire ER410 of diameter 2.4 mm with agglomerated flux in valve seat ring and valve wedges. Hardfacing is carried out using two stainless steel electrodes such as ER430 & ER410 simultaneously fed in twin wire torch in twin wire technique of submerged arc welding process. This leads to less cycle time, lower consumables consumption while achieving the required mechanical and chemical requirement of the deposit.

Title of Invention

AN IMPROVED METHOD FOR HARDFACING MARTENSTIC STAINLESS STEEL CARRIED OUT BY SUBMERGED ARC WELDING (SAW) TECHNIQUE

Abstract

Thus the invention is directed to a further development that the dissimilar wire combination is fed using a single wire feeder with a single nozzle drawing power from a single power source with parameters of 425 A, 28 V and 0.5 m/min as welding speed. A single weld pool is created in which the required weld chemistry are achieved by the use of two wires of different composition. This results in savings in consumables, cost and time. Accordingly to the present invention, the submerged arc welding wires ER430 of diameter 2.4 mm is used to deposit as buffer layer over the deposit finally hardfacing is carried out using the wire ER410 of diameter 2.4 mm with agglomerated flux in valve seat ring and valve wedges. Hardfacing is carried out using two stainless steel electrodes such as ER430 & ER410 simultaneously fed in twin wire torch in twin wire technique of submerged arc welding process. This leads to less cycle time, lower consumables consumption while achieving the required mechanical and chemical requirement of the deposit.

Full Text	FIELD OF INVENTION The invention relates to a process development for making hardfacing of different combination of filler wires using twin submerged arc welding applications, More particularly, the invention relates to an improved method of hard facing of martenstic stainless steel adapting submerged welding technique. BACKGROUND OF THE INVENTION Hard facing is widely used for deposition of weld metal for corrosion resistance and wear control applications In steel mills, chemical, nuclear and thermal power plant equipment. This is normally carried out using single wire conventional submerged arc welding process. In present practice, the submerged arc welding wire (E430) 15-18 cr of diarneter 24 mm Is used for depositing 3 buffer layer after machining the final layer, the final layer being made with submerged arc welding wire of (E410) 11- 13.5 Cr of diameter 2.4 mm along with agglomerated flux having hard faced in to the valve seat ring and valve wedges. This current practice is a time consuming process being compressed of the steps of making buffer layer, machining and forming the final layer to attain the required chemistry and hardness. US patent 4,572f936 discloses a submerged arc multiple wire welding system, in which only one or two of the welding wires used are over or mlcroalloyed wires. The other wires are commercially available unalloyed or low-alloyed solid wires. The process produces a weld metal which has unexpectedly high toughness values, and can be performed more economically, This multiple wire welding system is used in single or multiple-pass welding operations. 1 This process comprises a multiple wire system. That means they are feeding the wires separately using different power sources and different wire feeders as mentioned in the examples 1 to 4 of US patent. 'The first wire was connected to 81OA at 30 V, the second wire was connected at 790 A at 33 V. The third wire was connected to 680 A at 34 V. However, this process is aiso time consuming and call for costly equipment. OBJECTS OF THE INVENTION It is therefore, an object of the present invention to propose an improved method of hardfacing of martenstic stainless steel in valve wedges and seat rings using a twin wire submerged arc welding. Another object of the present invention is to propose an improved method of hardfacing of martenstic stainless steel in which fillers of dissimilar compositions can be used by adapting a twin wire submerged arc welding process, resulting in reduced consumption of consumables. Another object of the invention is to propose an improved method of hardfating of martenstic stainless steel in which dissimilar fillers are used by adapting a twin wire technique which create a common weld pool to attain required composition according to the code of highest quality welds, thereby achieving economy. SUMMARY OF THE INVENTION Thus the invention is directed to a further development that the dissimilar wire combination is fed using a single wire feeder with a single nozzle drawing power from a single power source with parameters of 425 A, 28 V and 0.5 m/min as welding speed A single weld pool is created in whitch the required weld 2 chemistry are achieved by the use of two wires of different composition. This results in savings In consumables, cost and time. Accordingly to the present invention, tne submerged arc welding wires ER430 of diameter 2,4 mm is used to deposit as buffer layer over the deposit finally hardfacing is carried out using the wlre ER410 of diameter 2.4 mm with agglomerated flux in valve seat ring and valve wedges. Hardfacing is carried out using two stainless steel electrodes such as ER430 & ER410 simultaneously fed in twin wire torch In twin wire technique of submerged arc welding process. This leads to less cycle time, lower consumables consumption wimte achieving the required mechanical and chemical requirement of the deposit. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig, 1 is a prospective view of a twin-wire feeding device adaptable to Twin wire submerged arc welding technique for hardfacing which achieves the method for hardfacing martenstic stainless steef according to an invention, DETAILED DESCRIPTION OF A PREFFEREP EMBODIMENT OF THE INVENTION A twin wire feeding device can be fitted to conventional submerged arc welding machine. By this technique same/different composition (1) of filler materials weld metal combination can be done effectively. The construction of the twin wire feeding device (2) is shown in fig, 1. The dissimilar wire combination is fed using a single wire feeder with single nozzle drawings power from a single power source (6) with parameters of 425 A, 28 V and 0.5 m/min as 3 welding speed. Thus, a single weld pool is created in which the required weld chemistry are obtained by the use of two wires of different composition. In this technique, to attain the required hardness properties as well as the required microstructure of the weld metal, an improved technique of twfn wire submerged arc welding is adapted in which a common arc pool (4) is created, in the arc cavity, the hardfacing fillers with different chemical composition of different alloy wires are fed simultaneously in a singte torch as sbow in m fig. 1 l.e., one after another which creates the common weld pool to give the desired weld properties. This new method enables welding/surfacing to be carried out in grooves having a width of different sizes. The new twin wire technique can be used surfadng/hardfacing of valves wedges and seat rings (3) of different sizes. This technique can be used for both manual as well as mechanized mode. This results in savings in consumables cost and time. 4 WE CLAIM 1. An improved method for hardfacing marts nstic stainless steel by adapting submerged arc welding technique comprising the steps of: - electrically coupling a plurality of welding wires to a source of eiectricai energy; - feeding wires of different composition in a single wire feeder with a single nozzle drawing power from a single power source. 2. The method as claimed in claim 1, wherein the plurality of welding wires comprises dissimilar wire combination, and wherein said dissimilar wires are fed in a single wire having a single nozzle. 3. The method as claimed in claim 1 or 2, wherein a common weld pool is created by using the dissimilar wire combination in a single feeder. 4. The method as claimed In claim 1, wherein the created flux is analytically neutral, 5. The method as claimed in any one of the proceeding claims, where in the weld metal structure is produced with a high proportion martensetic structure, 6. The method as claimed in claim 1, where in the surface proportions of the martensetic is 100 percent. 5 7. The method as claimed in claim 1, wherein a single pass welding is performed, 8. An improved method for hardfacing martenstic stainless steel by adapting submerged arc welding technique as substantially described herein with reference to the accompanying drawings. Dated this 23rd day of MARCH 2006. 6

Full Text

FIELD OF INVENTION
The invention relates to a process development for making hardfacing of
different combination of filler wires using twin submerged arc welding
applications, More particularly, the invention relates to an improved method of
hard facing of martenstic stainless steel adapting submerged welding technique.
BACKGROUND OF THE INVENTION
Hard facing is widely used for deposition of weld metal for corrosion resistance
and wear control applications In steel mills, chemical, nuclear and thermal power
plant equipment. This is normally carried out using single wire conventional
submerged arc welding process. In present practice, the submerged arc welding
wire (E430) 15-18 cr of diarneter 24 mm Is used for depositing 3 buffer layer
after machining the final layer, the final layer being made with submerged arc
welding wire of (E410) 11- 13.5 Cr of diameter 2.4 mm along with agglomerated
flux having hard faced in to the valve seat ring and valve wedges. This current
practice is a time consuming process being compressed of the steps of making
buffer layer, machining and forming the final layer to attain the required
chemistry and hardness.
US patent 4,572f936 discloses a submerged arc multiple wire welding system, in
which only one or two of the welding wires used are over or mlcroalloyed wires.
The other wires are commercially available unalloyed or low-alloyed solid wires.
The process produces a weld metal which has unexpectedly high toughness
values, and can be performed more economically, This multiple wire welding
system is used in single or multiple-pass welding operations.
1

This process comprises a multiple wire system. That means they are feeding the
wires separately using different power sources and different wire feeders as
mentioned in the examples 1 to 4 of US patent. 'The first wire was connected to
81OA at 30 V, the second wire was connected at 790 A at 33 V. The third wire
was connected to 680 A at 34 V. However, this process is aiso time consuming
and call for costly equipment.
OBJECTS OF THE INVENTION
It is therefore, an object of the present invention to propose an improved
method of hardfacing of martenstic stainless steel in valve wedges and seat rings
using a twin wire submerged arc welding.
Another object of the present invention is to propose an improved method of
hardfacing of martenstic stainless steel in which fillers of dissimilar compositions
can be used by adapting a twin wire submerged arc welding process, resulting in
reduced consumption of consumables.
Another object of the invention is to propose an improved method of hardfating
of martenstic stainless steel in which dissimilar fillers are used by adapting a twin
wire technique which create a common weld pool to attain required composition
according to the code of highest quality welds, thereby achieving economy.
SUMMARY OF THE INVENTION
Thus the invention is directed to a further development that the dissimilar wire
combination is fed using a single wire feeder with a single nozzle drawing power
from a single power source with parameters of 425 A, 28 V and 0.5 m/min as
welding speed A single weld pool is created in whitch the required weld
2

chemistry are achieved by the use of two wires of different composition. This
results in savings In consumables, cost and time.
Accordingly to the present invention, tne submerged arc welding wires ER430 of
diameter 2,4 mm is used to deposit as buffer layer over the deposit finally
hardfacing is carried out using the wlre ER410 of diameter 2.4 mm with
agglomerated flux in valve seat ring and valve wedges. Hardfacing is carried out
using two stainless steel electrodes such as ER430 & ER410 simultaneously fed
in twin wire torch In twin wire technique of submerged arc welding process. This
leads to less cycle time, lower consumables consumption wimte achieving the
required mechanical and chemical requirement of the deposit.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig, 1 is a prospective view of a twin-wire feeding device adaptable to Twin wire
submerged arc welding technique for hardfacing which achieves the method for
hardfacing martenstic stainless steef according to an invention,
DETAILED DESCRIPTION OF A PREFFEREP EMBODIMENT OF THE
INVENTION
A twin wire feeding device can be fitted to conventional submerged arc welding
machine. By this technique same/different composition (1) of filler materials weld
metal combination can be done effectively. The construction of the twin wire
feeding device (2) is shown in fig, 1. The dissimilar wire combination is fed using
a single wire feeder with single nozzle drawings power from a single power
source (6) with parameters of 425 A, 28 V and 0.5 m/min as
3

welding speed. Thus, a single weld pool is created in which the required weld
chemistry are obtained by the use of two wires of different composition. In this
technique, to attain the required hardness properties as well as the required
microstructure of the weld metal, an improved technique of twfn wire submerged
arc welding is adapted in which a common arc pool (4) is created, in the arc
cavity, the hardfacing fillers with different chemical composition of different alloy
wires are fed simultaneously in a singte torch as sbow in m fig. 1 l.e., one after
another which creates the common weld pool to give the desired weld
properties.
This new method enables welding/surfacing to be carried out in grooves having a
width of different sizes. The new twin wire technique can be used
surfadng/hardfacing of valves wedges and seat rings (3) of different sizes. This
technique can be used for both manual as well as mechanized mode. This results
in savings in consumables cost and time.
4

WE CLAIM
1. An improved method for hardfacing marts nstic stainless steel by adapting
submerged arc welding technique comprising the steps of:
- electrically coupling a plurality of welding wires to a source of
eiectricai energy;
- feeding wires of different composition in a single wire feeder with a
single nozzle drawing power from a single power source.
2. The method as claimed in claim 1, wherein the plurality of welding wires
comprises dissimilar wire combination, and wherein said dissimilar wires
are fed in a single wire having a single nozzle.
3. The method as claimed in claim 1 or 2, wherein a common weld pool is
created by using the dissimilar wire combination in a single feeder.
4. The method as claimed In claim 1, wherein the created flux is analytically
neutral,
5. The method as claimed in any one of the proceeding claims, where in the
weld metal structure is produced with a high proportion martensetic
structure,
6. The method as claimed in claim 1, where in the surface proportions of the
martensetic is 100 percent.
5

7. The method as claimed in claim 1, wherein a single pass welding is
performed,
8. An improved method for hardfacing martenstic stainless steel by adapting
submerged arc welding technique as substantially described herein with
reference to the accompanying drawings.
Dated this 23rd day of MARCH 2006.

6

Documents:

00246-kol-2006-claims.pdf

00246-kol-2006-description complete.pdf

00246-kol-2006-drawings.pdf

00246-kol-2006-form 1.pdf

00246-kol-2006-form 2.pdf

00246-kol-2006-form 3.pdf

00246-kol-2006-gpa.pdf

246-KOL-2006-(26-10-2012)-ABSTRACT.pdf

246-KOL-2006-(26-10-2012)-CLAIMS.pdf

246-KOL-2006-(26-10-2012)-CORRESPONDENCE.pdf

246-KOL-2006-(26-10-2012)-DESCRIPTION (COMPLETE).pdf

246-KOL-2006-(26-10-2012)-DRAWINGS.pdf

246-KOL-2006-(26-10-2012)-FORM-1.pdf

246-KOL-2006-(26-10-2012)-FORM-2.pdf

246-KOL-2006-(26-10-2012)-OTHERS.pdf

246-KOL-2006-CORRESPONDENCE.pdf

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Patent Number

255217

Indian Patent Application Number

246/KOL/2006

PG Journal Number

06/2013

Publication Date

08-Feb-2013

Grant Date

04-Feb-2013

Date of Filing

23-Mar-2006

Name of Patentee

BHARAT HEAVY ELECTRICALS LIMITED

Applicant Address

REGIONAL OPERATIONS DIVISION (ROD), PLOT NO : 9/1, DJBLOCK, 3RD FLOOR, KARUNAMOYEE, SALT LAKE CITY, KOLKATA-700091, HAVING ITS REGISTERED OFFICE AT BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	MANNARSAMY RAMAKRISHNAN	WELDING RESEARCH INSTITUTE, BHEL, TRICHY-620014
2	KRISHNASWAMY PRDMANABAN	WELDING RESEARCH INSTITUTE, BHEL, TRICHY-620014

PCT International Classification Number

N/A

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA