Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTI ON
The present lnvention pertains to electrodes,
wires, or rods which are typically used for welding, soldering,
brazing or hard-facing applications. Such electrodes
typically contain filler materials therein along the length
thereof. The filler ingredients in the core of such
electrodes may include base metals, alloys, flux forming
ingredients, deoxidizers, arc stabilizers and the like
; typically in particulate, powder or granular form.
A typical flux cored electrode of the prior art is
disclosed in U.S. Patent in 3,051,822. As taught therein such
electrode is cons~ructed of strip steel formed into tubular
; shape. The tube is formed of the metal to be consumed and
transferred to a weld. The èlectrode further includes a
core of alloy and flux forming ingredients. After the tubular
electrode is closed around the core, the tube may be
successively drawn or rolled to smaller diameters. Such
cold reduction of the cross section of the tube compacts the
core materials, in place, and eliminates void spaces
throughout the length of the elec~rode.
Compaction of core materials inside an electrode
i5 necessary to insure that the filler materials are
distributed uniformly and held in position to prevent such
materials from flowing from the core of the electrode
during welding, soldering, brazing and hard-facing.
.
2 ~
1 The prior art teaches various alternative methods
of holding electrode core materials in place, including the
following. U.S. Patent 1,650,905 teaches the preferred use
of a carbonaceous binder to hold filler materials in a
generally rectangular, open, trough-shaped welding rod.
Also U~Sr Patent 1,891,546 teaches double sheathing of core
materials to prevent the opening of a soldering or brazing
rod during handling. U.S. Patent 4,137,446, which also
pertains to the use of an inner metallic sheath to isolate
the filler materials from ~he weld joint of an outer sheath,
shows a welding wire having a rectangular configuration.
This invention pertains to a generally
rectangular, two piece electrcde housing granular core
materials thereinO The prior art methods of holding
the granular electrode Piller materials in position, as
,discussed above, are not conqidered adequate for the
electrode of the present invention. Accordingly, a new and
improved electrode, and method of making such electrode
are desired which insureæ that granular electrode core
~aterials are held in position within a two piece generally
rectangular electrode.
The present invention may be ~ummarized as providing
an improved method oP making a generally rec~angular continuous
electrode having a wldth to thicknes~ ratio of at least 4:1
comprislng the steps of forming sheet metal into a first
continuous trough ~haped sheath, Pilling the trough with
granular core materials and enclo ing the trough.
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~i2~63
l The core materials are restricted within the electrode by
intermittently mechanically depressing a portion of at
least one electrode wall inwardly of the electrode.
An objective of the present invention is to
provide a new and improved method of restricting electrode
core materials within a two piece, generally rectangular
electrode, particularly electrodes having a large width to
thickness ratio, wherein conventional drawing or rolling is
unable to prevent shiftin~ of the filler materials in the
core.
The above and other ob~ectives and advantages of
this invention will be more fully understood and appreciated
with reference to the following description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1-5 show, sequentially, and in cross
section, various stages of a process for formin~ a two piece
generally rec~angular core filled electrode of the present
lnvention.
Figure 6 is a cross-sectional view of an
alternative electrode of the present invention prior to
restriction of the core materials.
Figure 7 is a cross-sectional view of the
electrode shown in Figure 6 after restriction of the core
materials.
--4--
1 Figure 8 is a cross-sectional view of a trough-
shaped sheath of the present invention as an alternative to
the trough-shaped sheath shown in ~igure 1.
Figure 9 is a cross-sectional view of an
alternative electrode of the present invention.
Figures 10-12 and Figures 13-15 show alternative
seaming arrangements of the present invention in enlarged
cross-section.
Figure 16 is a cross sectional view of an
alternative seaming arrangement for an electrode formed from
the trough-shaped sheath illustrated in Figure 8, prior to
restriction of the core materials.
Figures 17-20 show sequentially, and in cross-
section, various stages of a process for forming a one-piece
generally circular trough into a generally rectangular
electrode in accordance with the present invention.
DETAILED DESCRIPTION
The electrodes which are the subject of the
present invention are those used in welding, soldering,
brazing and hard-facing applications. It is conventional to
construct such electrodes of a sheet metal housing or
sheath disposed around and enclosing granular core
materials in the central portion of the electrode. Common
electrodes are generally of tubular construction, typically
having a diameter on the order of about 1/16 to 1/4 inch.
The present invention, on the other hand, is directed
to a generally rectangular electrode having a width to
~2~3
1 thickness ratio of at least 4:1. Such generally rectangular
electrodes are particularly useful in applications such
as overlay welding and cladding of a base metal with
higher alloy materials for the purpose of enhancing wear
resistance, corrosion resistance and the like. It should be
understood that the term generally rectangular is to be
given broad interpretation, and in particular, is meant to
include ovular structures, as well as structures which do
not have substantially planar walls, wherein the maximu~
width to maximum thickness ratio is at least 4:1.
Referring particularly to the drawings, Figures
1-5 illustrate sequentially, in cross-section, exemplary
steps involved in making an electrode of the present invention.
As shown in Figure 1, a first step in forming an electrode
of the present invention may involve forming a strip of
sheet metal into a rectangular, trough-shaped sheath 10
having a botto~ wall 12 and sidewalls 14 and 16~ As shown
in Figure 2, the end portions of the sidewalls 14 and 16 may
be formed into a ledge or step 18 for receiving a closure
20 for the electrode as explained in detail belowO Forming
sheet metal in accordance with the present invention is
considered, in and of i~self~ known technology. Therefor~,
the tools and dies which may be utilized to form the sheet
metal of the present invention are not illustrated herein.
~he electrode of the present invention may be
provided with a sheath of any metal which lends itself to
the desired configuration as explained below. Typically,
tlle sheath 10 is made of mild steel, stainless steel,
copper, aluminum, nickel, cobalt or alloys thereof.
;3
1 It should be apparent that the formation of
the electrode of the present invention is a continuous
operationA It is conventional that a coil of strip material
would be continuously fed through appropriate tools and dies
to form a trough-shaped sheath 10 such as that illustrated
in Figure 1. After the strip is formed into the trough-
shaped sheath, the sheath is fed through appropriate feeding
mechanisms which fill the trough with appropriate filler
materials, or core materials 22.
The core materials 22 are granular in form,
including particulate and powder materials. Typical core
ingredients for electrodes include slag forming ingredients,
deoxidizers and various alloying ingredients. Additionally,
.
weld metal powder such as iron powder may be added to the
core of an electrode of the present invention. A typical
core composltion of an electrode of the present invention
for an austenitic stainless steel weld deposit may consist
of a mixture of the following ingredients:
~ Per Cent
-
Ferrochrome61.5Q
Nickel 25.50
Manganese 2.00
Ferrosilicon2.00
~ Iron Powder9.00
; , 25 Total 100.00
It is conventional to feed electrode core
materials ~rom a hopper through a metering feeder and onto a
moving conveyor which feeds a trough-shaped sheathO By
such conventional feeding equipment, the feed rate, in terms
~iZ~63
1 of volu~e, can be stringently controlled. It is also
conventional to employ a scraper or doctor blade above the
trough to remove any excess core materials from the trough
prior to closing the core. In order to minimize void spaces
in the core and to assist in compaction of the core, the
doctor blade may be arranged to permit slight overfill of
the core materials 22 into the trough-shaped sheath 10 as
illustrated in Figure 2.
After the sheath 10 is filled with core materials
22, a separate cover, lid or closure 20 may be placed over
the sheath 10. A typical closure 20 comprises a generally
planar strip of sheet metal which is continuously disposed
over the filled trough 10. It should be understood that the
type of metal employed for the closure 20 may or may not be
the same as that employed for the trough 10. The core
materials should be completely enclosed within the electrode.
As shown in Figure 4, the edges of the strip 20 are then
mechanically bound with the edges of the sheath 10~ This is
typically accomplished by crimping or seaming the respective
edges with one another.
A single seam, or crimp may be provided as shown
in Figure 4 by folding the end portions of the sheath walls
14 and 16 over the edged portions of the strip 20.
Alternatively, as shown in Figures 10, 11 and 12 and ;n
1 25 Figures 13, 14 and 15 a double seam or side seam may be
provided. Also, the bulk of the finished seam may be
disposed 3bove the closure 20 as shown in Figure 12, or
adjacent the side walls 14 and 16 as shown in Figure 16. It
should ~e understood that the various crimps or seams shown
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~ l~ ~
~z~v~
1 in the drawings may be further compressed with the appropriate
equipment such as by passing the seam through a pair of
flattening rolls. What is required of the crimp or seam of
the present invention is that the closure 20 remain attached
to the sheath 10 during subsequent forming operations and
during handling, winding and operation of the electrode of
the present invention. It should be further understood that
the seamed area of the electrode of the present invention
may be strengthened by spot welding or the liker
As explained above, the sheath ln may be slightly
overfilled, as shown in Figure 2, to accommodate a certain
degree of compaction of filler materials 22 as the closure
20 is attached thereto. Despite such preliminary compaction
of the filler materials, further compartmentalization must
be effected to assure that the core materials 22 remain
in-place during the handling, coiling and operation of the
electrode of the present invention. In accordance with the
present invention, a portion o~ at least one electrode wall
is intermittently, mechanically depressed inwardly toward
the core 22 to restrict the electrode core materials 22 into
compartments within the electrode.
Intermittent, mechanical depression of a portion
of at least one wall of the electrode may be accomplished by
a variety of methods. For example, a series of score lines
may be provided in one or both electrode walls defining the
width of the electrode. 5uch score lines may have the
effect of thinn1ng the metal wall in certain of the
depressed areas, but should not cut through the metal wall.
163
1 The preferred method of restricting the electrode
materials 22 is by knurling at least one wall of the
electrode. Any knurling pattern which accomplishes the
required restriction and, perhaps, densification of the core
materials 22 may be employed, the most common being a
diamond pattern. Rnurling efficiently creates a number of
core compression pockets or cavities 24 within the electrode
each defined within each indentation pattern, or knurl
pattern 26. As a result of knurling, the core materials 22
formerly located at the points of the knurl pattern 26 may
be forced into a compression cavity, or pocket 24, in such a
manner that the free flow of the core materials 22 is
restricted.
As discussed above, the preferred process of
mechanically depressing a rectangular electrode of the
present invention 1s by knurling which compresses the
granular core materials 22 into compartments such that free
flow i6 restricted. This means that because of such
compartmentalization the core materials 22 cannot flow
~0 freely from the tubular electrode without some form of
external impact or agitation. The knurl pattern may be of
any configuration, such as diamond, ~quare or parallel, but
mu~t be able to restrict the flow of core materials 22~
The spacing of the knurl patterns may depend upon
the thickness of ~he originally seamed electrode, the gauge
, ~
of the ~etal sheath 10 and closure ~0, the type of metal
employed and the particle Ri~e of the granular core
material~ 22 inside the electrode. Typical BpacingS between
knurl pattern~ can be expected to be less than about one-
--10--
1 half inch, although larger patterns may be comprehended in
certain conditions~ It is also expected that the knurl
patterns would be spaced at least about one-sixteenth inch
from one another. It has been found that a mechanical
depression must be provided within a spacing of about 25% of
the width of the electrode in order for the core materials
to be adequately restricted. In other words, the size of
any undepressed area, at least on one side of the electrode
which is provided with mechanical depressions, must have at
least one dimension which does not exceed 25~ o~ the maximu~
wldth of the electrode.
During knurling, precautions may be taken to
hold the seam, or crimp, from dislodging or otherwise coming
loose~ In certain instances it may be necessary or helpful
to weld the joint after seaming or crimping. It has been
found that in some applications seam disassembly may be
avoided by knurling the bottom wall 12 which is located more
remotely from the seam than the cover 20. Alternatively,
either or both sidewalls 14 and 16 of an electrode as shown
in Figures 8 and 16 may be knurled with little or no effect
on the seam. However, it should be understood that the
present lnvention applies to the knurling, or other mechanical
depression of either electrode wall, or both electrode
walls, defining the larger width dimension w of the electrode
~5 of the present invention over the continuous length of the
electrode. Those skilled in the art should appreciate that
the entire length of an electrode may be provided with
mechanical depressions by intermittently alternating the
side tha~ is depressed or knurled~ Consideration may have
~2~L~3
1 to be given to the particular knurl pattern employed to
restrict the core materials. For example if the rectangular
electrode of the present invention is to be coiled, a knurl
pattern which compliments coiling should be usedO A
rectangular knurl pattern disposed with its rectangle length
parallel with the longitudinal axis of the electrode may
create stress patterns in the sheet metal which resist
coiling. Alternatively, rectangular knurl patterns disposed
with the rectangle length perpendicular to the longitudinal
axis of the electrode may contribute to the efficient
coiling of the electrode.
A further result of knurling can be bulging of the
6idewalls 14 and 16 of the electrode as illustrated in
Figure 7. However, if desired such sidewalls 14 and 16 may
be given side support during knurling to prevent bulging
during knurling and to produce an electrode such as that
shown in Figure 9 with generally planar sidewalls.
In certain instances it may be beneficial to
~inter the core materials 22 or to utilize binders
in the core. Such methods would contribute to the restriction
o the free ~low of the granular materials from the
gen~rally rectangular electrode of the present invention.
Additionally, resi-tance welding, ~pot welding, multiple
sPam weld1ng, electron beam welding and laser welding may be
utilized to as~ist in holdiny the granular filler materials
22 ~nd the seam in po~ition in the electrode.
In an alternative embodiment~ ~s ~llustrated in
F~gures 17-20, a generally circular trough i~ filled with
-12-
1 core materials 22. Then the edge portions are bound, such
as by the interlocking seam or crimp arrangement shown in
Figure 18. After seaming, the electrode may be flattened
into a generally rectangular structure having ~ width to
thickness ratio of at least about 4:1, as shown in Figure
19. Thereafter, at least one side of the rectangular
electrode is mechanically depressed to restrict the core
materials 22, in place, in the electrode. It should be
understood that the flattening and the knurling operation
may be performed simultaneously by the present in~ention.
Also, the flat~ening operation may have the beneficial
effect of tightening the electrode seam.
Rect~ngular electrodes are generally used for
the s~me purposes as conventional tubular electrodes.
However, it has been found that electrodes of rectangular
construction may deposit a greater amount of weld metal over
a wide area at one time with a minimum of dilution of the
base metal into the weld metal. A rectangular electrode has
the advantage of spreading a great amount of power over a
greater area. With conventional tubular electrodes this
can only be accomplished by manually or automatically
oscillatiny the electrode. ~he possibility of a defect
in the weld metal is thu~ reduced with the rectangular
electrode of the present invention as compared to
~5 -oscillatin~ application6 with tubular electrodes.
~ypical rectangular electrodes of the present
inventlon would have the ollowing characteristicR:
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1 Example 1 Example 2
Sheath: AISI alloy: 1002 1008
dimension (inch)
trough: oOll x 1.671 .011 x 1.671
cover:~011 x 1.340.011 x 1.340
Core: Composition (Per Cent)
FeCr (73.8% Cr~ 61.50
FeMn (77% Mn;
6.6% C) - 3.50
F~Mo (62~ Mo) - 3.75
FeSi (50~ Si) 2.00 11.25
Ni 25.00
Mn 2.00
Cr (86.5~ Cr,
10.5% C) - 62.25
Graphite - 4.25
Fe Powder_ 9.00 15.00
Total 100.00 100.00
Fill (Per Cent) 55% 50~
Density (g/cc~ 3.25 3.00
Type of Deposit: Austenitic Stainless Hard-Facing
Whereas the particular embodiments of this
inven~ion have been described above for the purpos~s of
illustration, it will be apparent to those skilled in the
25 art that numerous variations of the details may be made
~ithout departing from the zpirit of the invention.
I claim-
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