Title of Invention	METHOD FOR PRODUCTING ELECTRODE WIRE FOR GAS METAL ARC WELDING
Abstract	A method of producing Copper free electrode wire for gas method arc welding comprising steps: - pickling of the wire rod having diameter in the range of 5-5.5mm applying hydrochloric acid solution to remove the oxide layer present on the surface, - boraxing and phosphating the wire rod so formed, - dry drawing of the wire rod, diameter in the range of 2-3mm, - pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid solution to produce pits or grooves on the drawn surface, - drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied with potassium based compound along with silicon free conductive grease to the 0.8-1.2 mm diameter wire, characterized in that the electrode wire is provided with a plurality of pits and grooves, potassium based compound filled in the pits and grooves, said electrode wire being drawn to form deformed pits and grooves for effective trapping of the potassium based compound, and the conductive grease being present on the surface provides the electrical conductivity of the wire.

Title of Invention

METHOD FOR PRODUCTING ELECTRODE WIRE FOR GAS METAL ARC WELDING

Abstract

A method of producing Copper free electrode wire for gas method arc welding comprising steps: - pickling of the wire rod having diameter in the range of 5-5.5mm applying hydrochloric acid solution to remove the oxide layer present on the surface, - boraxing and phosphating the wire rod so formed, - dry drawing of the wire rod, diameter in the range of 2-3mm, - pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid solution to produce pits or grooves on the drawn surface, - drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied with potassium based compound along with silicon free conductive grease to the 0.8-1.2 mm diameter wire, characterized in that the electrode wire is provided with a plurality of pits and grooves, potassium based compound filled in the pits and grooves, said electrode wire being drawn to form deformed pits and grooves for effective trapping of the potassium based compound, and the conductive grease being present on the surface provides the electrical conductivity of the wire.

Full Text	Field of Application The invention relates to the field of Gas Metal Arc Welding (GMAW), used for joining two or more pieces of metals together in general and to a method of producing copper free electrode wire for GMAW, in particular. Background of the Invention & Prior Art Reference is made to the following publication: 1. D.B.Holliday, "Gas Metal Arc Welding," ASM Handbook, p.180-185. 2. M.Suban and J.Tusek, "Dependence of Melting Rate in MIG/MAG Welding on the Type of Shielding Gas Used," Journal of Materials Processing Technology, 119,(2000),p. 185-192. This GMAW process is widely used in the field of general fabrication, automobile, ship building and construction. Gas Metal Arc Welding (GMAW) is an arc welding process widely used for joining at least two pieces of metals together. Required heat of welding is generated from an electric arc that is established in between a consumable electrode (wire) and the work piece. An externally supplied gas or gas mixtures act to shield the arc and the molten weld pool. In this process Ar or CO2 or mixture of it are used as shielding gas. Schematically GMAW process is shown in Figures 1 and 2. For the purpose of satisfying quality requirements for a welding electrode wire, conductive metal such as copper is conventionally plated on wire surface for smooth welding operation. However, nevertheless several advantage the copper plated wire, it also has following drawbacks: (A) Sometime copper is deposited in the form of copper dust in the dents of the wire surface. During welding process this dust falls from the wire surface and clogging the welding torch, and therefore, causing welding instability. (B) The copper plating is softer than the steel wire surface and thus inevitably peels off from the surface due to the friction between wire and the welding torch and thereby causing welding instability due to clogging of torch. (C) Copper coating gives barrier protection to the steel wire. However, by any means if the copper coating peels off or damage, the steel wire corrodes at much faster rate as compare to bare steel wire. (D) The melting point of copper is 1083°C and it is easily vaporized at ultra high temperature during welding operation, generates copper fume which is detrimental to environment. (E) The density of copper is higher than the iron; as a result the surface tension of copper is higher than the iron. During metal transfer in copper plated wire the droplet is not in spherical form but is in the form of ellipsoid which is elongated along the droplet transfer direction. This cause instantaneous short circuit between droplet and molten pool and facilitates the spatter generation. But in copper plating free wire, no such kind of instantaneous short circuit phenomenon is observed resulting less spatter generation. (F) During copper plating hazardous chemicals such as H2SO4 and CuSO4 are used. Object of invention Copper plated GMAW electrode wire is not only produces hazardous copper fume but also causes spatter loss and clogging of nozzle during welding. A new environmental friendly copper free alternate coating has been proposed to develop which gives higher corrosion resistance, smooth arc, better feedability, less fume generation, less spatter and improved yield. The present invention proposes to produce a new coating, free from copper to overcome the above drawbacks of the copper coating. Summary of the Invention Grooves or pits are produced on the; surface of the drawn wire by means of pickling and other mechanical process. These pits are the potential site of the deposition of the arc stabilizing compound. Compounds of alkali metal such as potassium are used as arc stabilizer, It is mainly due to the lower ionization potential of the potassium which is readily releases electrons and forms ions which stabilize the arc. Potassium can be used in the form of potassium carbonate or potassium stearate. Silicone free conductive grease is applied on the wire surface, which not only enhance the electrical conductivity of the wire but also helps in smooth feeding during welding and gives barrier protection against the corrosion of the bare wire. Brief description of the accompanying drawings Fig.1: Shows schematic of GMAW Process. Fig.2: Shows schematic view illustrating droplet transfer (a) when wire plated with copper and (b) when wire without copper plating. Fig. 3: Shows schematic view of the wire surface (a) before pickling (b) after pickling (c) just before drawing and (d) after drawing. Detailed Description of the Invention The invention will now be described with help of the accompanying drawings which depict an exemplary embodiments of the invention. However, there can be several other embodiments, all of which are covered by the description. The 5-5.5 mm diameter wire rod is pickled using standard hydrochloric acid solution to remove the oxide layer present on the surface. After boraxing and phosphating this wire rod is drawn upto 2-3mm diameter by dry drawing process. The 2-3 mm diameter wire is again pickled using hydrochloric acid to produce sufficient amount of pits or groves on the drawn surface. After pickling, dry drawing followed by wet drawing of the wire is carried out upto the 0.8-1.2 mm diameter wire. During the drawing operation potassium based compound like potassium carbonate and potassium stearate followed by Silicone free conductive grease are used. Figure 3(a-d) shows schematically the surface of the wire at different stages of processing. As shown in Figure 3(b) by pickling operation pits or grooves are formed on the surface of the wire. Arc stabilizing compounds fills in these pits on the wire surface, shown in Figure 3(c). After drawing these pits are deformed and the arc stabilizing compounds are trapped effectively within these pits, as shown schematically in Figure 3(d). Some more relevant details to produce copper free gas metal arc welding electrode wire by the following route: 1. Pickling of the wire rod (Diameter 5-5.5 mm) using hydrochloric acid solution as per following parameters: Concentration: 5-25% Temperature: 25-80° C Time: 10-40 minutes. 2. Dry drawing of the wire rod upto the 2-3 mm diameter wire after boraxing. 3. Pickling of the wire (Diameter 2-3 mm) using hydrochloric acid solution as per following parameters: Concentration: 5-25% Temperature: 25-80° C Time: 10-40 minutes 4. After boraxing and phosphating dry drawing (diameter: 2-3 mm) followed by wet drawing of the wire using potassium based compound like potassium carbonate and potassium stearate along with Silicone free conductive grease to the 0.8-1.2 mm diameter wire. We Claim: 1. A method of producing Copper free electrode wire for gas method arc welding comprising steps: - pickling of the wire rod having diameter in the range of 5-5.5mm applying hydrochloric acid solution to remove the oxide layer present on the surface, - dry drawing of the wire rod, diameter in the range of 2-3mm, - boraxing and phosphating the wire rod so formed, - pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid solution to produce pits or grooves on the drawn surface, - drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied with potassium based compound along with silicon free conductive grease to the 0.8-1.2 mm diameter wire, characterized in that the electrode wire is provided with a plurality of pits and grooves, potassium based compound filled in the pits and grooves, said electrode wire being drawn to form deformed pits and grooves for effective trapping of the potassium based compound, and the conductive grease being present on the surface provides the electrical conductivity of the wire. 2. The method as claimed in claim 1, wherein said potassium based compound is selected from potassium carbonate and potassium stearate. 3. The method as claimed in claim 2, wherein the potassium based compound is provided in combination with silicon free conductive grease. 4. The method as claimed in claim 1, wherein said pickling of wire rod for both dry and wet drawing are carried out with hydrochloric acid solution under conditions: - Concentration of acid : 5-25% - Temperature: 25-80° C - Time of treatment: 10-40 minutes 5. The method as claimed in claim 1, wherein said pickling of wire after dry drawing (diameter: 2-3mm) is done to produce pits and grooves for filling stabilizing compounds on the surface of the wire. 6. The method as claimed in claim 1, wherein said wet drawing of wire (diameter: 0.8-1.2mm) in carried out to trap the arc stabilizing compounds within pits, deformed thereby. 7. The method as claimed in claim 1, wherein said potassium based compound are provided to release electron readily to form ions, which stabilizes the arc, due to the lower ionization potential of potassium. 8. The method as claimed in claim 1, wherein said silicon free conductive grease is applied on the wire surface, which not only enhances the electrical conductivity of the wire but also helps in smooth feeding during welding and gives barrier protection against the corrosion of bare wire. A method of producing Copper free electrode wire for gas method arc welding comprising steps: - pickling of the wire rod having diameter in the range of 5-5.5mm applying hydrochloric acid solution to remove the oxide layer present on the surface, - boraxing and phosphating the wire rod so formed, - dry drawing of the wire rod, diameter in the range of 2-3mm, - pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid solution to produce pits or grooves on the drawn surface, - drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied with potassium based compound along with silicon free conductive grease to the 0.8-1.2 mm diameter wire, characterized in that the electrode wire is provided with a plurality of pits and grooves, potassium based compound filled in the pits and grooves, said electrode wire being drawn to form deformed pits and grooves for effective trapping of the potassium based compound, and the conductive grease being present on the surface provides the electrical conductivity of the wire.

Full Text

Field of Application
The invention relates to the field of Gas Metal Arc Welding (GMAW), used for
joining two or more pieces of metals together in general and to a method of
producing copper free electrode wire for GMAW, in particular.
Background of the Invention & Prior Art
Reference is made to the following publication:
1. D.B.Holliday, "Gas Metal Arc Welding," ASM Handbook, p.180-185.
2. M.Suban and J.Tusek, "Dependence of Melting Rate in MIG/MAG Welding on
the Type of Shielding Gas Used," Journal of Materials Processing Technology,
119,(2000),p. 185-192.
This GMAW process is widely used in the field of general fabrication, automobile,
ship building and construction.
Gas Metal Arc Welding (GMAW) is an arc welding process widely used for joining
at least two pieces of metals together. Required heat of welding is generated
from an electric arc that is established in between a consumable electrode (wire)
and the work piece. An externally supplied gas or gas mixtures act to shield the
arc and the molten weld pool. In this process Ar or CO2 or mixture of it are used
as shielding gas. Schematically GMAW process is shown in Figures 1 and 2.
For the purpose of satisfying quality requirements for a welding electrode wire,
conductive metal such as copper is conventionally plated on wire surface for
smooth welding operation. However, nevertheless several advantage the copper
plated wire, it also has following drawbacks:

(A) Sometime copper is deposited in the form of copper dust in the dents of the
wire surface. During welding process this dust falls from the wire surface and
clogging the welding torch, and therefore, causing welding instability.
(B) The copper plating is softer than the steel wire surface and thus inevitably
peels off from the surface due to the friction between wire and the welding torch
and thereby causing welding instability due to clogging of torch.
(C) Copper coating gives barrier protection to the steel wire. However, by any
means if the copper coating peels off or damage, the steel wire corrodes at
much faster rate as compare to bare steel wire.
(D) The melting point of copper is 1083°C and it is easily vaporized at ultra high
temperature during welding operation, generates copper fume which is
detrimental to environment.
(E) The density of copper is higher than the iron; as a result the surface tension
of copper is higher than the iron. During metal transfer in copper plated wire the
droplet is not in spherical form but is in the form of ellipsoid which is elongated
along the droplet transfer direction. This cause instantaneous short circuit
between droplet and molten pool and facilitates the spatter generation. But in
copper plating free wire, no such kind of instantaneous short circuit phenomenon
is observed resulting less spatter generation.
(F) During copper plating hazardous chemicals such as H2SO4 and CuSO4 are
used.

Object of invention
Copper plated GMAW electrode wire is not only produces hazardous copper fume
but also causes spatter loss and clogging of nozzle during welding. A new
environmental friendly copper free alternate coating has been proposed to
develop which gives higher corrosion resistance, smooth arc, better feedability,
less fume generation, less spatter and improved yield.
The present invention proposes to produce a new coating, free from copper to
overcome the above drawbacks of the copper coating.
Summary of the Invention
Grooves or pits are produced on the; surface of the drawn wire by means of
pickling and other mechanical process. These pits are the potential site of the
deposition of the arc stabilizing compound. Compounds of alkali metal such as
potassium are used as arc stabilizer, It is mainly due to the lower ionization
potential of the potassium which is readily releases electrons and forms ions
which stabilize the arc. Potassium can be used in the form of potassium
carbonate or potassium stearate. Silicone free conductive grease is applied on
the wire surface, which not only enhance the electrical conductivity of the wire
but also helps in smooth feeding during welding and gives barrier protection
against the corrosion of the bare wire.
Brief description of the accompanying drawings
Fig.1: Shows schematic of GMAW Process.
Fig.2: Shows schematic view illustrating droplet transfer (a) when wire plated
with copper and (b) when wire without copper plating.
Fig. 3: Shows schematic view of the wire surface (a) before pickling (b) after
pickling (c) just before drawing and (d) after drawing.

Detailed Description of the Invention
The invention will now be described with help of the accompanying drawings
which depict an exemplary embodiments of the invention. However, there can be
several other embodiments, all of which are covered by the description.
The 5-5.5 mm diameter wire rod is pickled using standard hydrochloric acid
solution to remove the oxide layer present on the surface. After boraxing and
phosphating this wire rod is drawn upto 2-3mm diameter by dry drawing
process. The 2-3 mm diameter wire is again pickled using hydrochloric acid to
produce sufficient amount of pits or groves on the drawn surface. After pickling,
dry drawing followed by wet drawing of the wire is carried out upto the 0.8-1.2
mm diameter wire. During the drawing operation potassium based compound
like potassium carbonate and potassium stearate followed by Silicone free
conductive grease are used.
Figure 3(a-d) shows schematically the surface of the wire at different stages of
processing. As shown in Figure 3(b) by pickling operation pits or grooves are
formed on the surface of the wire. Arc stabilizing compounds fills in these pits on
the wire surface, shown in Figure 3(c). After drawing these pits are deformed
and the arc stabilizing compounds are trapped effectively within these pits, as
shown schematically in Figure 3(d).
Some more relevant details to produce copper free gas metal arc welding
electrode wire by the following route:
1. Pickling of the wire rod (Diameter 5-5.5 mm) using hydrochloric acid solution
as per following parameters:
Concentration: 5-25%
Temperature: 25-80° C
Time: 10-40 minutes.
2. Dry drawing of the wire rod upto the 2-3 mm diameter wire after boraxing.

3. Pickling of the wire (Diameter 2-3 mm) using hydrochloric acid solution as per
following parameters:
Concentration: 5-25%
Temperature: 25-80° C
Time: 10-40 minutes
4. After boraxing and phosphating dry drawing (diameter: 2-3 mm) followed by
wet drawing of the wire using potassium based compound like potassium
carbonate and potassium stearate along with Silicone free conductive grease to
the 0.8-1.2 mm diameter wire.

We Claim:
1. A method of producing Copper free electrode wire for gas method arc welding
comprising steps:
- pickling of the wire rod having diameter in the range of 5-5.5mm applying
hydrochloric acid solution to remove the oxide layer present on the surface,
- dry drawing of the wire rod, diameter in the range of 2-3mm,
- boraxing and phosphating the wire rod so formed,
- pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid
solution to produce pits or grooves on the drawn surface,
- drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied
with potassium based compound along with silicon free conductive grease to the
0.8-1.2 mm diameter wire,
characterized in that the electrode wire is provided with a plurality of pits and
grooves, potassium based compound filled in the pits and grooves, said electrode
wire being drawn to form deformed pits and grooves for effective trapping of the
potassium based compound, and the conductive grease being present on the
surface provides the electrical conductivity of the wire.
2. The method as claimed in claim 1, wherein said potassium based compound is
selected from potassium carbonate and potassium stearate.
3. The method as claimed in claim 2, wherein the potassium based compound is
provided in combination with silicon free conductive grease.
4. The method as claimed in claim 1, wherein said pickling of wire rod for both
dry and wet drawing are carried out with hydrochloric acid solution under
conditions:
- Concentration of acid : 5-25%

- Temperature: 25-80° C
- Time of treatment: 10-40 minutes

5. The method as claimed in claim 1, wherein said pickling of wire after dry
drawing (diameter: 2-3mm) is done to produce pits and grooves for filling
stabilizing compounds on the surface of the wire.
6. The method as claimed in claim 1, wherein said wet drawing of wire
(diameter: 0.8-1.2mm) in carried out to trap the arc stabilizing compounds within
pits, deformed thereby.
7. The method as claimed in claim 1, wherein said potassium based compound
are provided to release electron readily to form ions, which stabilizes the arc, due
to the lower ionization potential of potassium.
8. The method as claimed in claim 1, wherein said silicon free conductive grease
is applied on the wire surface, which not only enhances the electrical conductivity
of the wire but also helps in smooth feeding during welding and gives barrier
protection against the corrosion of bare wire.

A method of producing Copper free electrode wire for gas method arc welding
comprising steps:
- pickling of the wire rod having diameter in the range of 5-5.5mm applying
hydrochloric acid solution to remove the oxide layer present on the surface,
- boraxing and phosphating the wire rod so formed,
- dry drawing of the wire rod, diameter in the range of 2-3mm,
- pickling the wire, diameter drawn in the range 2-3mm, with hydrochloric acid
solution to produce pits or grooves on the drawn surface,
- drawing dry (diameter: 2-3 mm) followed by wet drawing of the wire applied
with potassium based compound along with silicon free conductive grease to the
0.8-1.2 mm diameter wire,
characterized in that the electrode wire is provided with a plurality of pits and
grooves, potassium based compound filled in the pits and grooves, said electrode
wire being drawn to form deformed pits and grooves for effective trapping of the
potassium based compound, and the conductive grease being present on the
surface provides the electrical conductivity of the wire.

Documents:

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Patent Number

272023

Indian Patent Application Number

1980/KOL/2008

PG Journal Number

12/2016

Publication Date

18-Mar-2016

Grant Date

14-Mar-2016

Date of Filing

07-Nov-2008

Name of Patentee

TATA STEEL LIMITED

Applicant Address

JAMSHEDPUR

Inventors:

#	Inventor's Name	Inventor's Address
1	MR. SUJIT CHATTERJEE	TATA STEEL LIMITED, JAMSHEDPUR-831001
2	MR. ANIRBAN CHAKRABORTY	TATA STEEL LIMITED, JAMSHEDPUR-831001

PCT International Classification Number

B23K35/22;B23K35/38

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA