U.S. patent application number 15/954814 was filed with the patent office on 2018-08-23 for bimetallic welding electrode.
The applicant listed for this patent is The ESAB Group Inc.. Invention is credited to Nathanael Micah Colvin, Valerio Cozzi, James G. Schopp.
Application Number | 20180236610 15/954814 |
Document ID | / |
Family ID | 50389121 |
Filed Date | 2018-08-23 |
United States Patent
Application |
20180236610 |
Kind Code |
A1 |
Colvin; Nathanael Micah ; et
al. |
August 23, 2018 |
BIMETALLIC WELDING ELECTRODE
Abstract
An electrode is disclosed for use in MIG/MAG welding. The
electrode comprises an elongated electrode body within which is
embedded a metallic filament. In some embodiments, the filament is
copper, and is offset from the center of the electrode body. A
method is disclosed for forming an electrode. The method may
include removing oxidation from a surface of an electrode body,
forming the electrode body to a desired size and geometry, removing
lubricants from the surface of the electrode body, forming an
elongated channel in a surface of the electrode body, depositing a
filament in the elongated channel, and forming the electrode body
over the filament. Other embodiments are disclosed and claimed.
Inventors: |
Colvin; Nathanael Micah;
(Spartanburg, SC) ; Cozzi; Valerio; (Varese,
IT) ; Schopp; James G.; (York, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The ESAB Group Inc. |
Florence |
SC |
US |
|
|
Family ID: |
50389121 |
Appl. No.: |
15/954814 |
Filed: |
April 17, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
14034661 |
Sep 24, 2013 |
9969032 |
|
|
15954814 |
|
|
|
|
61705222 |
Sep 25, 2012 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
Y10T 29/49982 20150115;
Y10T 29/4998 20150115; B23K 35/0261 20130101; B23K 35/302 20130101;
B23K 35/406 20130101; Y10T 29/49993 20150115; B23K 35/3053
20130101 |
International
Class: |
B23K 35/30 20060101
B23K035/30; B23K 35/40 20060101 B23K035/40; B23K 35/02 20060101
B23K035/02 |
Claims
1. A method of making a welding wire, comprising: forming an
elongated channel in a welding wire, the welding wire having a
longitudinal axis, the elongated channel being offset from the
longitudinal axis; depositing a first material in the elongated
channel; and deforming the welding wire to fix the first material
to the welding wire.
2. The method of claim 1, wherein the first material is a metal
filament.
3. The method of claim 1, wherein the welding wire comprises steel
and the metal filament comprises copper.
4. The method of claim 1, wherein the first material is an arc
enhancing material.
5. The method of claim 1, wherein the arc enhancing material is
selected from the list consisting of lithium, sodium, potassium,
cesium rubidium, tungsten and carbon, including their forms in
either a salt, compound molecule or elemental form.
6. The method of claim 1, further comprising depositing a second
material in the elongated channel, wherein the step of deforming
the welding wire fixes the first material and the second material
to the welding wire.
7. The method of claim 6, wherein the first material is a metal
filament and the second material is an arc enhancer.
8. The method of claim 6, wherein the first material is an alloying
element and the second material is an arc enhancer.
9. The method of claim 1, a longitudinal axis of the elongated
channel is oriented parallel to the longitudinal axis of the
welding wire.
10. The method of claim 1, wherein the first material is an
alloying element.
11. The method of claim 10, wherein the alloying element is
selected from the list consisting of carbon, silicon, manganese,
chromium, molybdenum, nickel and vanadium.
12. A method of making a welding wire, comprising: forming an
elongated channel in a welding wire; depositing a first material in
the elongated channel; depositing a second material in the
elongated channel; and deforming the welding wire to secure the
first and second materials within the elongated channel.
13. The method of claim 12, wherein the elongated channel is offset
from a longitudinal axis of the welding wire and oriented parallel
to the longitudinal axis of the welding wire.
14. The method of claim 12, wherein the first material is an arch
enhancing material.
15. The method of claim 14, wherein the second material is a metal
filament.
16. The method of claim 14, wherein the second material is an alloy
material in the form of a strip.
17. The method of claim 15, wherein deforming the welding wire
further comprises: feeding the welding wire between a pair of pinch
rollers that forcibly press the metal filament into the elongated
channel while forcing walls of the elongated channel inward to
partially enclose the metal filament such that a portion of the
metal filament is exposed to a surface of the welding wire.
18. The method of claim 15, wherein deforming the welding wire
further comprises: feeding the welding wire between a pair of pinch
rollers that forcibly press the metal filament into the elongated
channel while forcing walls of the elongated channel inward to
fully enclose the metal filament within the elongated channel.
19. The method of claim 12, wherein forming an elongated channel in
a welding wire further comprises: feeding the welding wire between
a pair of rollers disposed in an opposing laterally-spaced
relationship, where one of the rollers includes a circumferential
projection that is forcibly pressed into an outer surface of the
welding wire to form the elongated channel.
20. The method of claim 12, wherein the elongated channel has a
substantially rounded U-shaped cross-section.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Non-Provisional
patent application Ser. No. 14/034,661, filed on Sep. 24, 2013,
entitled "BIMETALLIC WELDING ELECTRODE," which claims the benefit
of U.S. Provisional Patent Application Ser. no. 61/705,222, filed
Sep. 25, 2012. The disclosures of the above applications are
incorporated herein by reference in their entirety.
FIELD OF THE DISCLOSURE
[0002] The disclosure relates generally to the field of consumable
welding electrodes and more particularly an improved bimetallic
welding electrode and method of making the same.
BACKGROUND OF THE DISCLOSURE
[0003] In the art of gas metal arc welding it is common practice to
use a process in which a metal wire, often referred to as a
consumable electrode, is advanced through a welding gun while
electrical energy is transmitted to the electrode by an electrified
contact tip of the welding gun. Exemplary techniques for gas metal
arc welding include MIG (Metal Inert Gas) and MAG (Metal Active
Gas), with the difference between the two primarily being the type
of shielding gas used. Typical inert gases are argon and helium.
Typical active gases are mixtures of argon, carbon dioxide and
oxygen.
[0004] In MIG/MAG-welding, the workpiece is heated primarily by an
arc. The electrode is heated, partly by the power supplied when the
weld current flows through the electrode and partly by the arc
itself. MIG/MAG-welding takes place in one of three states. In
short arc welding, the material transport from the electrode to the
workpiece takes place through large short-circuiting droplets. When
the supplied power is increased, the process passes into the mixed
arc area, where the material transport takes place through a
mixture of short-circuiting and non-short-circuiting droplets. The
result is an unstable arc with significant weld spatter and weld
smoke. Welding in this area is normally avoided. At a sufficiently
high supplied power, the process enters the spray area, where
material transport takes place through small finely dispersed
droplets without short circuits. The third state is referred to as
pulsed welding and means that, by means of advanced control, proper
cut off of the droplets can be controlled by means of a suitable
current pulse. Each pulse cuts off a droplet and the droplets
become sufficiently small so as not to short-circuit. This method
results in advantages from the spray area in the form of low weld
spatter without the disadvantages of large heat transfer.
[0005] MIG/MAG welding electrodes are generally offered in two
basic varieties: bare and coated. Both varieties can be alloyed
with additional materials and provided with surface additives for
enhancing performance characteristics, such as arc stability and
feeding resistance. Bare electrodes, sometimes referred to as solid
or uncovered electrodes, typically consist of a bare, base metal
wire, such as may be formed primarily of steel, aluminum or
stainless steel, that is drawn down to a desired diameter. Bare
electrodes generally provide good arc start and stability between
an electrode and a workpiece, as well as low feeding resistance and
minimal spatter when melted. However, a problem commonly associated
with bare electrodes is poor current transfer between an electrode
and the contact tip of a welding gun. Current transfer instability
can result in significant wear on the contact tip over a relatively
short period of time, thus requiring frequent replacement of the
tip. Such replacement is both inconvenient and costly.
[0006] Coated electrodes, sometimes referred to as covered
electrodes, are substantially similar to bare electrodes but are
provided with an exterior coating of copper, such as may be applied
through conventional electroplating and electroless plating
processes. The copper coating provides superior current transfer
stability between the electrode and the tip of the welding gun
relative to bare electrodes, thus resulting in less tip wear and
less frequent tip replacement. However, coated electrodes are more
costly, have greater feeding resistance, produce more spatter, and
exhibit inferior arc start and arc stability between the electrode
and a workpiece relative to bare electrodes. Moreover, the
electroplating or electroless plating processes required for
producing coated electrodes require specialized facilities and
involve the use and disposal of caustic and acidic chemical agents
that are harmful to the environment.
SUMMARY
[0007] In view of the forgoing, it a consumable MIG/MAG welding
electrode is disclosed that facilitates good arc start and
stability between the electrode and a workpiece as well as good arc
stability between the electrode and a contact tip of a welding gun.
The disclosed MIG/MAG electrode also exhibits low feeding
resistance and produces minimal spatter when melted. A convenient
method is also disclosed for producing such an electrode that does
not require highly specialized facilities or equipment and that
does not involve the use, or require the disposal of, harmful
chemical agents.
[0008] The disclosed electrode is a hybrid electrode that will
fuses the production, environmental and welding benefits of bare
wire with the superior tip wear of copper-coated wire. The
disclosed electrode may include a current conducting filament. In
one exemplary embodiment, the current conducting filament may be
comprised of elemental copper. The current conducting filament may
also be made from one or more of the following: metallic elements,
compounds, plasmas, conductive polymers, salts and salt solutions
composed of one or more of the following: alkali element metals,
alkali element earth metals, transition element metals, and
non-element metals and graphite. A filament containing one or more
of these materials may be embedded into the surface of the MIG
wire, running parallel to the wire axis. The effect of the filament
present on the consumable MIG electrode is to serve as a
sacrificial material to stabilize the current interface erosion
process between the welding tip and the electrode.
[0009] The disclosed design may also include alloying elements
below the current conducting filament. The addition of the
contained arc enhancing element to the electrode body facilitates
the use of very reactive arc enhancers in the welding electrode due
to the removal of atmospheric interaction with the material sealed
below the surface filament. The addition of the alloying element in
or below the arc conducting filament will allow for the manufacture
to transform the filer metal from its base rod alloy to a new alloy
in its as finish welded state.
[0010] Benefits of the disclosed electrode and process of making
the disclosed electrode include elimination of the use of
environmentally harmful acid, caustic, and copper sulfate solutions
used in the copper plating process, reduction of contaminated waste
water generated during the copper plating process. In addition,
greater control of the copper filament lay process is achieved by
incorporating the filament at a rate of about 1-3 meters/second, as
opposed to plating which is normally achieved at rates of 24-25
meters/second.
[0011] In addition, the disclosed process facilitates the
standardization of rod alloys to one base alloy, thus reducing the
number of different types of rod alloys required to be stocked. All
finish alloying can be achieved through the introduction of the
metallic filament into the parent alloy of the stock rod.
[0012] In an exemplary embodiment, a rod element according to
normal product specification (e.g., S2, S3, S6) is provided.
Surface oxides are removed via one or more chemical or mechanical
processes. The rod element may be rolled/drawn using a reduction
die to ensure the wire has a concentric geometry. The surface of
the rolled/drawn wire may then be prepared, such as by the removal
of any remaining forming lubricants. The rod may then be roll
formed to create a longitudinal recess in the surface of the rod to
allow for the addition of a copper filament. A copper filament may
then be provided in the recess so that the longitudinal axis of the
filament aligns with the longitudinal recess. The filament may then
be compressed within the recess by die or roll forming such that
the filament is enclosed within the rod. The percentage of filament
material, expressed as a function of the total weight of the
resulting electrode, may be less than the AWS specification for
maximum copper content. The rod may then be drawn/rolled to obtain
a desired finish diameter.
[0013] In some embodiments, are enhancing agents/compounds are
introduced into the recess before the filament is provided in the
recess. If arc enhancers are disposed in the recess before the
filament, they will be enclosed within the rod during the
subsequent die or roll forming operation.
[0014] Further options for this portion of the process include not
only introducing the filament to the rod material, but also to
apply the principles of the invention to flux cored wire
technology. In such applications, a filament-embedded strip
material may be engineered that includes arc enhancers sealed in
the core. This option would maximize the retention of arc enhancing
material from below the filament in the mechanical fusion portion
of the process.
[0015] In additional embodiments, alloying elements may be
introduced into the recess formed in the rod. These alloying
elements may be introduced into the void and encapsulated with
either a copper strip or simply enveloped by the base material by
subsequent die or roll forming. The disclosed methods and
arrangements may facilitate the use of relative low generic grades
of steel, and custom alloying them in the factory to the
specifications of the customer.
[0016] In accordance with the present disclosure, a method for
adding an element or compound to the composition of a stock welding
electrode is provided. An embodiment of the method may include the
steps of removing oxidation from a surface of the stock electrode,
conforming the stock electrode to a desired size and geometry,
removing lubricants from the surface of the stock electrode, and
forming an elongated channel in the surface of the stock electrode.
The method may further include depositing a filament formed of an
additional element in the elongated channel, compressing the stock
electrode and the filament together, and reducing a diameter the
compressed stock electrode and filament to a desired size.
[0017] A bimetallic welding wire is disclosed. The welding wire may
comprise a wire having a longitudinal axis, the wire having an
elongated channel formed on a surface thereof. The elongated
channel may be aligned with a longitudinal axis of the elongated
member. The welding wire may include a first material disposed in
the elongated channel. The elongated channel may be offset from a
center of the welding wire.
[0018] A method of making a welding wire is disclosed. The method
may include forming an elongated channel in a welding wire, the
welding wire having a longitudinal axis, the elongated channel
being offset from the longitudinal axis; depositing a first
material in the elongated channel; and deforming the welding wire
to fix the first material to the welding wire.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] By way of example, specific embodiments of the disclosed
device will now be described, with reference to the accompanying
drawings, in which:
[0020] FIG. 1 is a schematic diagram of an exemplary device for
MIG/MAG-welding;
[0021] FIG. 2 is a schematic diagram illustrating an exemplary
arrangement for making an electrode in accordance with the
disclosure;
[0022] FIGS. 3A-3E are cross-section views of the electrode at
various points in the manufacturing process;
[0023] FIG. 4 is a schematic diagram illustrating an alternative
exemplary arrangement for making an electrode in accordance with
the disclosure;
[0024] FIG. 5 is a flow chart illustrating an exemplary method of
making an electrode in accordance with the disclosure; and
[0025] FIG. 6 is a flow chart illustrating an exemplary alternative
method of making an electrode in accordance with the
disclosure.
DETAILED DESCRIPTION
[0026] FIG. 1 illustrates an exemplary arrangement of welding
equipment used for MIG/MAG welding. A welding machine 10 includes a
power source 1 adapted to supply welding energy, or melting power,
to an electrode 7. In some cases, the power source 1 comprises an
inverter power supply. An electrode feeder 2 is provided on the
welding machine 10, and operates to feed the electrode 7 to a
welding torch 3. The welding torch 3 is connected to the electrode
feeder 2, the welding machine 10 and a gas container 4 via a
welding cable. The welding torch 3 comprises a gas cup 5 and a
contact tube 6 through which the electrode 7 is fed to a position
in the proximity of the workpiece 8. Welding gas is supplied from
the gas container 4 to the space enclosed between the gas cup 5 and
the contact tube 6. The welding equipment may also comprise a
welding controller 20. The welding controller 20 includes a general
controller 21 which is arranged to control the welding current and
voltage by setting appropriate static and dynamic characteristics
for a work piece to be welded. The general controller 21 can also
be configured to regulate the feeding velocity of the electrode
feeder 2. The general controller 21 specifically sets a reference
voltage which is used as a reference for an average voltage during
the welding process.
[0027] Referring to FIGS. 2 and 3A-3E, an exemplary process is
illustrated for making electrodes for use with the welding machine
1 of FIG. 1. It will be appreciated that the disclosed electrodes
are not limited to use with the welding machine of FIG. 1, but
instead can be used with any of a variety of appropriate welding
equipment.
[0028] FIG. 2 shows an exemplary process for converting a length of
stock welding wire 22 into a bimetallic welding electrode having
enhanced performance characteristics in accordance with the present
disclosure. The stock wire 22 may be any variety of conventional
materials used for MIG/MAG welding, such as steel, aluminum,
stainless steel, or various composite materials, and may conform to
any desired electrode specification (e.g., S2, S3, S6, etc.). As
will be appreciated by those of ordinary skill in the art, the
stock wire may be alloyed with additional metals to improve certain
attributes of the resulting, such as arc stability, feeding
resistance, and susceptibility to surface oxidation.
[0029] Referring to FIGS. 2 and 3A-3E, a first embodiment of the
disclosed technique for manufacturing a MIG/MAG electrode will be
described. A stock wire 22 may be introduced into a reduction or
shaping die 24 along the direction of arrow "A." The reduction or
shaping die 24 may be configured to provide the wire with a
consistent, circular cross section. The wire 22 is then introduced
between first and second rollers 26, 28, at least one of which is
provided with a surface feature 30 configured to impart a
longitudinally-extending channel 32 to the surface of the wire 22.
In the illustrated embodiment, the pair of rollers 26, 28 are
disposed in an opposing, laterally-spaced relationship, and the
first rollers 26 includes a circumferential projection 30 extending
radially therefrom so that as the wire 22 is fed through the
rollers 26, 28, the projection 30 is forcibly pressed into the
surface of the wire 22, thus forming the longitudinally-extending
channel 32. The channel 32 is shown in FIG. 3A as having a
substantially rounded, U-shaped cross-section. It will be
appreciated, however, that the channel 32 may be provided in any of
a variety of different cross sectional shapes, such as rectangular,
V-shaped or the like. In addition, the dimensions of the channel 32
may be selected to accommodate the particular size and shape of the
material being deposited therein, and to ensure that at least a
portion of the filament is exposed to the surface of the resulting
electrode. The shape and size of the channel 32 may be controlled
through selection of the projection 30 used to form the channel
32.
[0030] In some embodiments, one or more arc enhancing materials 34
may be deposited in the channel 32. The arc enhancing materials may
provide the finished electrode with desired arc start and stability
characteristics. Examples of arc enhancing materials 34 include
lithium, sodium, potassium, cesium rubidium, tungsten, carbon and
the like including their forms in either a salt, compound molecule
or elemental form. Such materials 34 may be applied to an interior
surface of the channel 32. Nominal % of these material can range
from 1 g per kilogram to 100 g per kilogram depending on the
element and the welding application. If arc enhancing materials 34
are used, the channel 32 may be sized accordingly.
[0031] A current conducting filament 36 may be disposed in the
channel 32 so that it lays on top of the arc enhancing material 34
(where such materials are used). The arrangement of the wire 22,
arc enhancing materials 34 and filament 36 is shown in
cross-section in FIGS. 3B and 3C. The filament 36 may be drawn from
a spool 38 in a continuous fashion and laid into the channel 32 as
the wire 22 is moved in the direction of arrow "A." In some
embodiments, the filament 36 may comprise copper so as to provide
the resulting "bare" electrode with all of beneficial
characteristics of copper coated electrodes. The filament 36 may
have a diameter that results in a desired weight percent of copper
in relation to the base metal in the wire 22, such as may be
required by the particular application. In one non-limiting
exemplary embodiment, the filament is sized so that the resulting
electrode includes 0.12% copper, which may correspond to a filament
having a diameter of 0.012-inches. In other embodiments, the
filament 36 may be sized so that resulting electrode includes 0.5%
copper, such that a correspondingly larger filament may be used.
The channel 32 may be sized appropriately to fit within the
filament 36 in a closely conforming relationship therewith.
Although the filament 36 is shown as being circular in
cross-section, it will be appreciated that it can instead be
provided in other shapes, such as flat (strip), rectangular,
triangular, and the like.
[0032] The wire 22, with the filament 36 and optionally the arc
enhancing materials 34, may then be passed through a pair of
rollers 40, 42 disposed in an opposing, laterally-spaced
relationship. The rollers 26 and 28 may compress the wire, forcing
the walls of the channel 32 inward, and forming the wire material
over the filament so as to partially or completely enclose the
filament 36 within the wire 22. The cross-section at this stage is
shown in FIG. 3D. If arc enhancing materials 22 are used, they will
be sealed within the wire 22 along with the filament. Nominally the
base material will interface with the filament to join the filament
to the base material. The filament may be joined to the base
material via various methods to ensure it is held in place in the
base material.
[0033] Preferably, the filament material will be placed into the
base material in a manner that ensures that a portion of the
filament is exposed to the surface. The wire 22, including the
filament 36 and the arc enhancing materials (if used) may then be
introduced into a reduction die 44 to reduce the diameter of the
wire 22 to a desired final size and outer contour is provided. The
cross-section at this stage is shown in FIG. 3E. The finished
electrode 46 may be cut to a desired length and packaged, or may be
passed along for further processing.
[0034] As can be seen, the filament 36 (along with any arc
enhancing materials) are offset from the longitudinal axis "A" of
the finished electrode 46 by an offset distance "O," so that the
filament lies directly adjacent to the electrode's outer surface 47
and a portion of the filament is exposed to the outer surface 47.
The copper present on the electrode 46 wire will effectively serve
as a sacrificial material to stabilize the arc erosion process
between the tip and the electrode.
[0035] As previously noted, applying a copper or other current
transferring filament to the wire 22 in the manner described above
provides several advantages relative to conventional copper plating
techniques. The above-described process does not require
specialized electroplating equipment or facilities and may
therefore be performed on-site and on an as-needed basis by a
retailer or other non-manufacturer party. Moreover, the process of
the present disclosure does not require the use of acids, caustic
agents, or copper sulfate (CuSO.sub.4), and does not produce
contaminated waste water or fumes that can be harmful to the
environment.
[0036] Referring now to FIG. 4, an embodiment will be described in
which alloying materials may be introduced into a wire in a manner
similar to that described in relation to FIG. 2. As will be
appreciated, by providing alloying materials within a channel in a
generic wire, cost savings can be achieved by eliminating the need
to stock a large number of different wires having different alloy
compositions. Rather, a large volume of a relative small number of
different wire base materials can be stocked, and when an order is
received, a desired alloy formulation may be added to the base
material in an efficient and tightly controllable manner. In one
embodiment the base material of the stock wire 48 is steel. It will
be appreciated, however, that the invention is not so limited, and
other base materials can also be used, as desired. The disclosed
technique may facilitate the manufacture of most desired alloyed
grades starting from the same non-alloyed base wire material.
[0037] The stock wire 48 may be introduced into a reduction or
shaping die 50 along the direction of arrow "A." The reduction or
shaping die 50 may be configured to provide the wire with a
consistent, circular cross section. The wire 48 is then introduced
between first and second rollers 52, 54, at least one of which is
provided with a surface feature 56 configured to impart a
longitudinally-extending channel 58 to the surface of the wire 48.
In one embodiment, the surface feature 56 is a circumferential
projection extending radially therefrom so that as the wire 48 is
fed through the rollers 52, 54, the projection is forcibly pressed
into the surface of the wire 48, thus forming the
longitudinally-extending channel 58. The channel 58 may have some
or all of the characteristics described in relation to the channel
32 of FIGS. 2-3E.
[0038] In some embodiments, one or more alloying materials 60 may
be disposed in the channel 58. These alloying materials 60 may be
formulated so that a finished weld will have a desired material
composition. Examples of appropriate alloying materials include
Aluminum, Arsenic, Boron, Carbon, Calcium, Chromium, Copper,
Hydrogen, Mangenese, Molybdenum, Nitrogen, neodymium, Nickle,
Oxygen, Antimony, Silicon, Tin, Titanium, Tungsten, Zirconium and
the like in elemental, salt or compound format. In the illustrated
embodiment, the alloying material 60 is provided in the form of a
strip which is laid into the channel 58. Although not shown, in
some embodiments, are enhancing materials, similar to those
described in relation to FIGS. 2-3E may be disposed in the channel
58 so that the alloying material 60 is laid on top thereof. The
alloying material 60 may be drawn from a spool 62 in a continuous
fashion and laid into the channel 58 as the wire 48 is moved in the
direction of arrow "A." When provided in strip form, the alloying
material 60 may have a diameter that results in a desired material
composition of the resulting weld. The channel 58 may be sized
appropriately to fit around the alloying material 60 in a closely
conforming relationship therewith. The alloying material 60, when
provided in strip form, may have a cross-section that is circular,
flat (strip), rectangular, triangular, and the like.
[0039] The wire 48, with the alloying material 60 and optionally
the arc enhancing materials, may then be passed through a pair of
rollers 64, 66 disposed in an opposing, laterally-spaced
relationship. The rollers 64, 66 may compress the wire 48, forcing
the walls of the channel 58 inward, and forming the wire material
over the alloying material so as to partially or completely enclose
the alloying material within the wire 48. If arc enhancing
materials are used, they will be sealed within the wire 48 along
with the alloying material.
[0040] The wire 48, including the alloying material 60 and the arc
enhancing materials (if used) may then be introduced into a
reduction die 68 to reduce the diameter of the wire 48 to a desired
final size and outer contour is provided. The finished electrode 70
may be cut to a desired length and packaged, or may be passed along
for further processing.
[0041] As with the previously described embodiment, the additives
(the alloying material and any arc enhancing materials) are offset
from the longitudinal axis of the wire, at or beneath the wire's
surface. During welding, the alloying materials will combined with
the base wire material to result in a weld having desired alloy
properties.
[0042] It will be appreciated that the alloying material can also
be used in combination with a metal filament. In addition, in some
embodiments, a metal filament may be used in combination with arc
enhancing materials and alloying materials.
[0043] Referring now to FIG. 5, an exemplary method of making an
electrode will be described. At step 100, surface oxidation may be
removed from a stock wire using one or more chemical and/or
mechanical processes. At step 110, the wire may be drawn down
slightly to provide a desired consistent outer shape. At step 120,
a surface treatment may be performed to remove forming lubricants
from the surface of the wire. At step 130, a
longitudinally-extending channel may be formed in the wire using a
roll forming process. In one embodiment, the wire is fed between a
pair of rollers disposed in an opposing, laterally-spaced apart
relationship. One the rollers may include a circumferential
projection so that as the wire is fed between the rollers the
projection is forcibly pressed into the surface of the wire, thus
forming the channel therein. At optional step 140, one or more arc
enhancing elements or compounds may be deposited in the channel. At
step 150, a metal filament is disposed in the channel. The filament
may be formed of copper, for example, for providing the electrode
with beneficial characteristics that have heretofore been realized
by providing electrodes with a copper coating using conventional
copper plating processes. At step 160, the wire and filament may be
mechanically compressed by a die or roll forming process. In one
embodiment, the wire (with the embedded filament) may be fed
between a pair of pinch rollers so that the filament is forcibly
pressed into the channel and the walls of the channel are forced
inward to partially or completely enclose the filament. At step
170, the wire, including the filament and any additional optional
arc enhancing materials, may be drawn through a reduction die to
reduce the diameter of the wire to a desired final size and to
ensure concentric geometry. The resulting finished electrode may be
cut to a desired length and packaged, or may be passed along for
further processing.
[0044] FIG. 6 shows an exemplary alternative method according to
the disclosure. At step 200, surface oxidation may be removed from
a stock wire using one or more chemical and/or mechanical
processes. At step 210, the wire may be drawn down slightly to
provide a desired consistent outer shape. At step 220, a surface
treatment may be performed to remove forming lubricants from the
surface of the wire. At step 230, a longitudinally-extending
channel may be formed in the wire using a roll forming process. In
one embodiment, the wire is fed between a pair of rollers disposed
in an opposing, laterally-spaced apart relationship. One the
rollers may include a circumferential projection so that as the
wire is fed between the rollers the projection is forcibly pressed
into the surface of the wire, thus forming the channel therein. At
optional step 240, one or more arc enhancing elements or compounds
may be deposited in the channel. At step 250, an alloying element
is disposed in the channel. The alloying element may be formed of
Chromium, for example, for providing the ultimate weld metal with a
desired alloy composition. At step 260, the wire and alloying
element may be mechanically compressed by a die or roll forming
process. In one embodiment, the wire (with the embedded alloying
element) may be fed between a pair of pinch rollers so that the
alloying element is forcibly pressed into the channel and the walls
of the channel are forced inward to partially or completely enclose
the alloying element. At step 270, the wire, including the alloying
element and any additional optional arc enhancing materials, may be
drawn through a reduction die to reduce the diameter of the wire to
a desired final size and to ensure concentric geometry. The
resulting finished electrode may be cut to a desired length and
packaged, or may be passed along for further processing.
[0045] As used herein, an element or step recited in the singular
and proceeded with the word "a" or "an" should be understood as not
excluding plural elements or steps, unless such exclusion is
explicitly recited. Furthermore, references to "one embodiment" of
the present invention are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features.
[0046] While certain embodiments of the disclosure have been
described herein, it is not intended that the disclosure be limited
thereto, as it is intended that the disclosure be as broad in scope
as the art will allow and that the specification be read likewise.
Therefore, the above description should not be construed as
limiting, but merely as exemplifications of particular embodiments.
Those skilled in the art will envision other modifications within
the scope and spirit of the claims appended hereto.
* * * * *