U.S. patent application number 14/153131 was filed with the patent office on 2014-05-08 for modified flux system in cored electrode.
This patent application is currently assigned to LINCOLN GLOBAL, INC.. The applicant listed for this patent is Rajeev Katiyar. Invention is credited to Rajeev Katiyar.
Application Number | 20140124482 14/153131 |
Document ID | / |
Family ID | 36032104 |
Filed Date | 2014-05-08 |
United States Patent
Application |
20140124482 |
Kind Code |
A1 |
Katiyar; Rajeev |
May 8, 2014 |
MODIFIED FLUX SYSTEM IN CORED ELECTRODE
Abstract
A cored electrode having reduced moisture pick-up properties and
which forms a weld bead with low diffusible hydrogen in a gas
shielded electric arc welding process. The cored electrode includes
a metal sheath and a fill composition. The fill composition
includes titanium dioxide, slag forming agent and a
sodium-silica-titanate compound.
Inventors: |
Katiyar; Rajeev; (Highland
Heights, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Katiyar; Rajeev |
Highland Heights |
OH |
US |
|
|
Assignee: |
LINCOLN GLOBAL, INC.
City of Industry
CA
|
Family ID: |
36032104 |
Appl. No.: |
14/153131 |
Filed: |
January 13, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11099267 |
Apr 5, 2005 |
8629374 |
|
|
14153131 |
|
|
|
|
Current U.S.
Class: |
219/74 ;
219/137.2 |
Current CPC
Class: |
B23K 35/362 20130101;
B23K 35/368 20130101; B23K 9/173 20130101; B23K 35/3608 20130101;
B23K 35/3607 20130101 |
Class at
Publication: |
219/74 ;
219/137.2 |
International
Class: |
B23K 9/173 20060101
B23K009/173 |
Claims
1. A method of forming a weld bead having a low diffusible hydrogen
content by use of an electrode having reduced moisture pick-up
comprising: providing a cored electrode that includes a metal
sheath and a fill composition, said fill composition including
titanium dioxide, a slag forming agent and a moisture resistant
compound, said moisture resistant compound comprising a
sodium-silico-titanate compound, wherein said
sodium-silico-titanate compound is formed of a combination of a
titanium compound, a potassium compound, a sodium compound and
colloidal silica, said moisture resistant compound having an
average particle size of 30-250 mesh, said moisture resistant
compound including over 50 weight percent titanium compound, said
moisture resistant compound having a weight ratio of sedum compound
to potassium compound of about 1.1-5:1, said moisture resistant
compound including at least about 1 weight percent colloidal
silica, said colloidal silica having an average particle size of
less than about 40 nm; and, at least partially melting said cored
electrode by an electric current to cause said melted portion of
said cored electrode to be deposited on a workpiece.
2. The method as defined in claim 1, including the step of
directing a shielding gas to said workpiece to at least partially
shield said melted portion of said cored electrode being deposited
on a workpiece.
3. The method as defined in claim 2, wherein said shielding gas
includes argon, carbon dioxide or mixtures thereof.
4. The method as defined in claim 1, wherein said titanium dioxide
minus any titanium dioxide in said moisture resistant compound is
about 2-40 weight percent of said fill composition.
5. The method as defined in claim 2, wherein said titanium dioxide
minus any titanium dioxide in said moisture resistant compound is
about 2-40 weight percent of said fill composition.
6. The method as defined in claim 1, wherein said slag forming
agent constitutes about 10-50 weight percent of said fill
composition.
7. The method as defined in claim 5, wherein said slag forming
agent constitutes about 10-50 weight percent of said fill
composition.
8. The method as defined in claim 1, wherein said slag forming
agent includes a metal oxide.
9. The method as defined in claim 7, wherein a majority of said
slag forming agent includes said metal oxide.
10. The method as defined in claim 1, wherein said moisture
resistant compound constitutes about 1-40 weight percent of said
fill composition.
11. The method as defined in claim 9, wherein said moisture
resistant compound constitutes about 1-40 weight percent of said
fill composition.
12. The method as defined in claim 1, including a metal alloying
agent, said metal alloying agent including aluminum, magnesium,
silicon, titanium, and mixtures thereof.
13. The method as defined in claim 1, wherein said fill composition
includes: TABLE-US-00009 TiO.sub.2 2-50% Sodium-silico-titanate
compound 1-55% Slag forming Agent 1-60% Metal Alloying Agent
0-70%
14. The method as defined in claim 1, wherein said fill composition
includes: TABLE-US-00010 TiO.sub.2 3-40% Sodium-silico-titanate
compound 1-55% Slag forming Agent 20-50% Metal Alloying Agent
0-55%
15. The method as defined in claim 1, wherein said moisture
resistant compound includes by weight percent: TABLE-US-00011
TiO.sub.2 60-90% Sodium silicate 1-20% Potassium silicate 1-15%
Sodium compound 1-20% Colloidal Silica 1-10% Other components
0-5%
16. The method as defined in claim 15 wherein said moisture
resistant compound having reduced moisture pick-up such that the
moisture pick-up of said moisture resistant compound over a 96 hour
period at 80.degree. F. and 80% relative humidity is less than
about 0.2% for particles having an average particle size of 40-200
mesh.
17. The method as defined in claim 15 wherein said moisture
resistant compound includes by weight percent: TABLE-US-00012
TiO.sub.2 70-90% Sodium silicate 4-15% Potassium silicate 1-10%
Sodium carbonate 3-16% Colloidal Silica 2-6% Other components
0-1%
18. The method as defined in claim 17 wherein said moisture
resistant compound includes by weight percent: TABLE-US-00013
TiO.sub.2 70-80% Sodium silicate 3.5-10% Potassium silicate 1.5-6%
Sodium carbonate 5-15% Colloidal Silica 2-5% Other components
0-0.5%
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The application claims priority to, is a divisional of and
fully incorporates by reference, U.S. patent application Ser. No.
11/099,267 filed 5 Apr. 2005.
TECHNICAL FIELD
[0002] The invention relates generally to the field of welding and
more particularly directed to electrodes having improved weld bead
formation properties, and even more particularly directed to cored
electrodes having reduced moisture pick-up properties and which
form weld beads having reduced amounts of diffusible hydrogen.
BACKGROUND OF THE INVENTION
[0003] In the field of arc welding, the main types of welding
processes are gas-metal arc welding with solid (GMAW) or
metal-cored wires (GMAW-C), gas shielded flux-cored arc welding
(FCAW-G), self shielded flux-cored arc welding (FCAW-S), shielded
metal arc welding (SMAW) and submerged arc welding (SAW). Of these
processes, gas metal arc welding with solid or metal-cored
electrodes are increasingly being used for joining or overlaying
metallic components. These types of welding processes are becoming
increasingly popular because such processes provide increased
productivity and versatility. Such increase in productivity and
versatility results from the continuous nature of the welding
electrodes in gas metal arc welding (GMAW & GMAW-C) which
offers substantial productivity gains over shielded metal arc
welding (SMAW). Moreover, these electrodes produce very good
looking welds with very little slag, thus saving time and expense
associated with cleaning welds and disposing of slag, a problem
that is often encountered in the other welding processes.
[0004] In gas metal arc welding with solid or cored electrodes, a
shielding gas is used to provide protection for the weld against
atmospheric contamination during welding. Solid electrodes are
appropriately alloyed with ingredients that, in combination with
the shielding gas, provide porosity free welds with the desired
physical and mechanical properties. In cored electrodes, these
ingredients are on the inside, in the core (fill) of a metallic
outer sheath, and provide a similar function as in the case of
solid electrodes.
[0005] Solid and cored electrodes are designed to provide, under
appropriate gas shielding, a solid, substantially porosity free
weld with yield strength, tensile strength, ductility and impact
strength to perform satisfactorily in the final applications. These
electrodes are also designed to minimize the quantity of slag
generated during welding. Cored electrodes are used increasingly as
an alternative to solid wires because of increased productivity
during welding fabrication of structural components. Cored
electrodes are composite electrodes consisting of a core (fill)
material surrounded by a metallic outer sheath. The core consists
mainly of metal powder and fluxing ingredients to help with arc
stability, weld wetting and appearance etc., such that the desired
physical and mechanical properties are obtained in the weld. Cored
electrodes are manufactured by mixing up the ingredients of the
core material and depositing them inside a formed strip, and then
closing and drawing the strip to the final diameter. Cored
electrodes provide increased deposition rates and produce a wider,
more consistent weld penetration profile compared to solid
electrodes. Moreover, they provide improved arc action, generate
less fume and spatter, and provide weld deposits with better
wetting compared to solid electrodes.
[0006] In the art of welding, much prior effort has been expended
in developing flux compositions of the type having predetermined
flux components intended to perform in predetermined manners. A
large number of compositions have been developed for use as fluxes
in arc welding. Fluxes are utilized in arc welding to control the
arc stability, modify the weld metal composition, and provide
protection from atmospheric contamination. Arc stability is
commonly controlled by modifying the composition of the flux. It is
therefore desirable to have substances which function well as
plasma charge carriers in the flux mixture. Fluxes also modify the
weld metal composition by rendering impurities in the metal more
easily fusible and providing substances with which these impurities
may combine, in preference to the metal to form slag. Other
materials may be added to lower the slag melting point, to improve
slag fluidity, and to serve as binders for the flux particles.
[0007] Cored electrodes are commonly used in electric arc welding
of steel base metals. These electrodes generally yield high
strength welds in a single pass and multiple passes at high welding
speeds. These electrodes are formulated to provide a solid,
substantially nonporous weld bead with tensile strength, ductility
and impact strength to meet the desired end use of various
applications.
[0008] One of the many challenges during the formation of a weld
metal is to reduce the amount of diffusible hydrogen in the weld
bead. Diffusible hydrogen is a known cause of cracking in weld
beads. Many studies have shown that an increased amount of moisture
content in the flux system results in an increased amount of
diffusible hydrogen in the weld metal. Hydrogen in the weld metal
can result in hydrogen inducing cracking and eventual detrimental
failure of the weld. Sodium and potassium silicate are commonly
used as arc stabilizers and sometimes used in binder systems for
flux components. Potassium silicate is known for its high moisture
pick-up tendencies.
[0009] In view of the present state of the art of the fill
compositions used in conjunction with cored welding electrodes,
there is a need for a welding electrode that forms a weld bead
having a reduced hydrogen content.
SUMMARY OF THE INVENTION
[0010] The present invention pertains to welding electrodes, and
more particularly, to a welding electrode that includes a fill
composition having reduced moisture pick-up and which facilitates
in reducing the amount of hydrogen in the weld bead. The fill
composition of the present invention is particularly directed to
cored electrodes having a metal sheath that surrounds the fill
composition in the core of the sheath; however, the fill
composition can be applied to other types of electrodes (e.g.,
coating on a stick electrodes, etc.), or be used as part of a fill
composition in a submerged arc welding process. The fill
composition of the present invention is particularly formulated for
use with electrodes used to weld mild and low alloy steel; however,
the fill composition can be used with electrodes for the formation
of welding beads on other types of metals. The metal electrode is
typically formed primarily from iron (e.g., carbon steel, low
carbon steel, stainless steel, low alloy steel, etc.); however, the
base metal can be primarily formed of other materials. The fill
composition typically constitutes at least about 1 weight percent
of the total electrode weight, and not more than about 80 weight
percent of the total electrode weight, and typically about 8-60
weight percent of the total electrode weight, and more typically
about 10-40 weight percent of the total electrode weight, even more
typically about 11-30 weight percent of the total electrode weight,
and still even more about 12-20 weight percent of the total
electrode weight.
[0011] In one aspect of the present invention there is provided a
titanium dioxide based flux system that is formulated for use in a
flux cored electrode; however, it can be appreciated that the flux
system can be used in other types of welding systems. The flux
system of the present invention includes titanium dioxide, slag
forming agents and a moisture resistant compound. The titanium
dioxide content of the flux system, not including the titanium
dioxide content in the moisture resistant compound is generally at
least about 2 weight percent of the flux system, typically about
5-40 weight percent of the flux system, and more typically about
5-35 weight percent of the flux system; however, other weight
percentages can be used. The one or more slag forming agents in the
flux system are generally used to facilitate in the formation of
the weld bead and/or to at least partially shield the formed weld
bead from the atmosphere; however, the slag forming agents can have
other or additional functions. Non-limiting examples of such slag
forming agents include metal oxides (e.g., aluminum oxide, boron
oxide, calcium oxide, chromium oxide, iron oxide, magnesium oxide,
manganese oxide, niobium oxide, potassium oxide, sodium oxide, tin
oxide, vanadium oxide, zirconium oxide, etc.), metal carbonates
(e.g., calcium carbonate, etc.), and/or metal fluorides (e.g.,
barium fluoride, bismuth fluoride, calcium fluoride, potassium
fluoride, sodium fluoride, Teflon, etc.). The slag forming content
of the flux system is typically at least about 5 weight percent of
the flux system, typically about 10-60 weight percent of the flux
system, and more typically about 20-45 weight percent of the flux
system; however, other weight percentages can be used. The moisture
resistant compound is a unique combination of at least four
compounds, namely titanium dioxide, potassium compound, colloidal
silica, and sodium compound. The moisture resistant compound is
significantly less hygroscopic than flux systems that include
silicate compounds (e.g., potassium silicate, sodium silicate,
etc.). The potassium and sodium compounds of the moisture resistant
compound function as binders for the moisture resistant compound
and/or provide arc stability to the arc during a welding process.
The moisture resistant compound content of the flux system is
generally at least about 1 weight percent of the flux system,
typically about 2-40 weight percent of the flux system, and more
typically about 2-35 weight percent of the flux system; however,
other weight percentages can be used.
[0012] In another aspect of the present invention, the moisture
resistant compound is formulated to include a majority weight
percent titanium dioxide. and a certain weight percent ratio of
potassium oxide to sodium oxide. The titanium dioxide content of
the moisture resistant compound is at least about 60 weight
percent, typically about 75-92 weight percent, and more typically
about 80-88 weight percent; however, other weight percentages can
be used. The weight percent of the sodium compound in the moisture
resistant compound is generally greater than the weight percent of
the potassium compound; however, this is not required. The weight
percent ratio of sodium compound content to potassium compound
content of the moisture resistant compound is about 1.1-5:1,
typically about 1.5-3.5:1, and more typically about 2-3:1; however,
other weight percent rations can be used. The sodium compound is
typically sodium dioxide, sodium carbonate, and/or sodium silicate;
however, other or additional sodium compounds can be used. The
potassium compound is typically potassium oxide and/or potassium
silicate; however, other or additional potassium compounds can be
used. The sodium compound content of the moisture resistant
compound is at least about 3 weight percent of the moisture
resistant compound, typically about 5-15 weight percent of the
moisture resistant compound, and more typically about 7-12 weight
percent of the moisture resistant compound; however, other weight
percentages can be used. The moisture resistant compound can
include additional components such as, but not limited to, lithium
compounds (e.g., lithium hydroxide, lithium oxide, etc.), carbon,
sulfur, etc. The colloidal silica content of the moisture resistant
compound is typically at least about 1 weight percent, typically
about 2-10 weight percent, and more typically about 2-8 weight
percent; however, other weight percentages can be used. The average
particle size of the colloidal silica is less than about 40 nm,
typically about 0.5-20 nm, and more typically about 4-15 nm;
however, other sizes can be used. The source of silica can be
natural and/or artificial.
[0013] In still another aspect of the present invention, the
moisture resistant compound is typically formed by combining a
solution of colloidal silica with the other components of the
moisture resistant compound. The solution generally includes about
10-70 weight percent colloidal silica, typically about 15-50 weight
percent colloidal silica, and more typically about 25-40 weight
percent colloidal silica; however, other weight percentages can be
used. The water content of the solution is generally at least about
10 weight percent, typically about 30-80 weight percent, and more
typically about 60-75 weight percent; however, other weight
percentages can be used. The solution can also include other
components such as, but not limited to, sodium compound. When
sodium compound is included in the solution, the sodium compound
generally is sodium oxide; however, other or additional sodium
compounds can be used. The sodium compound content in the solution,
when included, is generally about 0.05-1.5 weight percent; however,
other weight percentages can be used. The pH of the solution is
typically basic; however, this is not required.
[0014] In still another aspect of the present invention, the
moisture resistant compound is processed such that the average
particle size of the moisture resistant compound is less than about
30 mesh, typically between about 40-250 mesh, and more typically
about 50-200 mesh. The moisture resistant compound is typically
ground to the desired particle size.
[0015] In yet another aspect of the present invention, the fill
composition includes one or more metal alloying agents, and/or one
or more deoxidizers. The one or more metal alloying agents are
generally included in the fill composition to at least closely
match the desired weld metal composition and/or to obtain the
desired properties of the formed weld bead. Non-limiting examples
of such alloying metals include aluminum, boron, calcium, carbon,
chromium, iron, manganese, nickel, silicon, titanium and/or
zirconium.
[0016] In still yet another aspect of the present invention, the
flux coded electrode generally includes a metal sheath. The metal
sheath generally includes a majority of iron when welding a ferrous
based workpiece (e.g., carbon steel, stainless steel, etc.);
however, the composition of the sheath can include various types of
metals to achieve a particular weld bead composition. In one
embodiment of the invention, the metal sheath primarily includes
iron and can include one or more other elements such as, but not
limited to, aluminum, antimony, bismuth, boron, carbon, cobalt,
copper, lead, manganese, molybdenum, nickel, niobium, silicon,
sulfur, tin, titanium, tungsten, vanadium, zinc and/or zirconium.
In still another and/or alternative embodiment of the invention,
the iron content of the metal sheath is at least about 80 weight
percent.
[0017] In a further and/or alternative aspect of the present
invention, a shielding gas is used in conjunction with the flux
cored electrode to provide protection to the weld bead from
elements and/or compounds in the atmosphere. The shielding gas
generally includes one or more gases. These one or more gases are
generally inert or substantially inert with respect to the
composition of the weld bead. In one embodiment, argon, carbon
dioxide or mixtures thereof are at least partially used as a
shielding gas. In one aspect of this embodiment, the shielding gas
includes about 2-40 percent by volume carbon dioxide and the
balance of argon. In another and/or alternative aspect of this
embodiment, the shielding gas includes about 5-25 percent by volume
carbon dioxide and the balance of argon. As can be appreciated,
other and/or additional inert or substantially inert gases can be
used.
[0018] It is a primary object of the invention to provide a welding
electrode that reduces moisture pick-up properties.
[0019] Another and/or alternative object of the present invention
is the provision of a welding electrode and welding process that
results in a reduction of the amount of diffusible hydrogen in the
weld bead.
[0020] Still another and/or alternative object of the present
invention is the provision of a welding process that includes the
use of a gas shielded cored electrode.
[0021] Yet another and/or alternative object of the present
invention is the provision of a welding electrode that includes
sodium-silico-titanate compound in a flux system to reduce moisture
pick-up of the flux system.
[0022] These and other objects and advantages will become apparent
from the discussion of the distinction between the invention and
the prior art and when considering the preferred embodiment.
BRIEF DESCRIPTION OF THE INVENTION
[0023] The cored electrode of the present invention overcomes the
past limitations of prior art cored electrodes by including a
sodium-silico-titanate compound that reduces the moisture pick-up
of the flux system of the cored electrode.
[0024] A general formulation of the fill composition (weight
percent) in accordance with the present invention is set forth as
follows:
TABLE-US-00001 TABLE I TiO.sub.2 2-50% Sodium-silico-titanate
compound 1-55% Slag forming Agent 1-60% Metal Alloying Agent
0-70%
[0025] In another more specific general formulation of the fill
composition (weight percent):
TABLE-US-00002 TABLE II TiO.sub.2 3-40% Sodium-silico-titanate
compound 1-55% Slag forming Agent 20-50% Metal Alloying Agent
0-55%
[0026] In another more specific general formulation of the fill
composition (weight percent):
TABLE-US-00003 TABLE III TiO.sub.2 20-40% Sodium-silico-titanate
compound 20-50% Slag forming Agent 25-45% Metal Alloying Agent
0-35%
[0027] In still another more specific general formulation of the
fill composition (weight percent):
TABLE-US-00004 TABLE IV TiO.sub.2 3-15% Sodium-silico-titanate
compound 15-25% Slag forming Agent 30-40% Metal Alloying Agent
35-45%
[0028] In yet another more specific general formulation of the fill
composition (weight percent):
TABLE-US-00005 TABLE V TiO.sub.2 20-30% Sodium-silico-titanate
compound 1-5% Slag forming Agent 20-30% Metal Alloying Agent
45-55%
[0029] In the above examples, the weight percent of the fill
composition is typically about 8-60 weight percent of the cored
electrode, and more typically about 10-28 weight percent of the
cored electrode; however, other weight percentages can be used. The
metal sheath that can be used to form the weld bead can include
about 0-0.2 weight percent B, about 0-0.2 weight percent C, about
0-12 weight percent Cr, about 0-5 weight percent Mn, about 0-2
weight percent Mo, less than about 0.01% N, about 0-5 weight
percent Ni, less than about 0.014% P, about 0-4 weight percent Si,
less than about 0.02% S, about 0-0.4 weight percent Ti, about 0-0.4
weight percent V and about 75-99.9 weight percent Fe. During an arc
welding process, a shielding gas is typically used with the cored
electrode; however, this is not required. When a shielding gas is
used, the shielding gas is typically a carbon dioxide and argon
blend.
[0030] The slag forming agent typically includes, but is not
limited to, metal oxides such as aluminum oxide, boron oxide,
calcium oxide, chromium oxide, iron oxide, magnesium oxide, niobium
oxide, potassium oxide, silicon dioxide, sodium oxide, tin oxide,
vanadium oxide and/or zirconium oxide. The metal alloying agent,
when used, typically includes, but is not limited to, aluminum,
boron, calcium, carbon, iron, manganese, nickel, silicon, titanium
and/or zirconium. The flux system can include other compounds such
as, but not limited to, metal carbonates (e.g., calcium carbonate,
etc.) and/or metal fluorides (e.g., barium fluoride, bismuth
fluoride, calcium fluoride, potassium fluoride, sodium fluoride,
Teflon, etc.). The particular components of the flux system
typically depend on the type of welding process (SAW, SMAW, FCAW)
to be used and/or the type of workpiece to be welded.
[0031] The sodium-silico-titanate compound is specifically
formulated to provide arc stability and to reduce moisture pick-up
of the flux system. The sodium-silico-titanate compound typically
includes titanium dioxide, potassium silicate, sodium silicate and
colloidal silica. The titanium dioxide content of the
sodium-silico-titanate compound typically is a majority weight
percent. The weight percent ratio of the sodium silicate to
potassium silicate is generally about 1.5-3.5:1, and more typically
about 1.75-2.5:1. Typically, a majority of the silicon dioxide that
forms the colloidal silica is from a pure source. Typically, the
particles of silica have an average particle size of about 2-25
nanometers, and more typically, an average particle size of about
6-12 nanometers. The sodium-silico-titanate compound can include
other sodium compounds such as, but not limited to sodium
carbonate. These sodium compounds can be used to provide arc
stability and/or gas shielding during the welding process. The
sodium-silico-titanate compound can also include other components
such as water, lithium compounds, sulfur, carbon, etc.; however,
this is not required. These other components, when included in the
sodium-silico-titanate compound typically constitute less than
about 10 weight percent of the sodium-silico-titanate compound.
[0032] The sodium-silico-titanate compound is typically formed by
mixing the solution of colloidal silica with the titanium oxide
(e.g., rutile), the silicates, and any other components of
sodium-silico-titanate compound. After the components of the
sodium-silico-titanate compound have been properly mixed together,
the sodium-silico-titanate compound is dried to remove the water
from the sodium-silico-titanate compound. After the
sodium-silico-titanate compound has been dried, the water content
of the sodium-silico-titanate compound is generally less than about
0.1 weight percent, typically less than about 0.08 weight percent,
and more typically, less than about 0.06 weight percent. After the
sodium-silico-titanate compound has been dried, the
sodium-silico-titanate compound is typically sized. This sizing
process is typically performed by a grinding and screening
operation; however, other or additional sizing processes can be
used. The average particle size of the sodium-silico-titanate
compound after sizing is typically less than 40 mesh and more
typically about 50-200 mesh.
[0033] Examples of the sodium-silico-titanate compound are set
forth below (weight percent of sodium-silico-titanate
compound):
EXAMPLE 1
TABLE-US-00006 [0034] TiO.sub.2 60-90% Sodium silicate 1-20%
Potassium silicate 1-15% Sodium compound 1-20% Colloidal Silica
1-10% Other components 0-5%
EXAMPLE 2
TABLE-US-00007 [0035] TiO.sub.2 70-90% Sodium silicate 4-15%
Potassium silicate 1-10% Sodium carbonate 3-16% Colloidal Silica
2-6% Other components 0-1%
EXAMPLE 3
TABLE-US-00008 [0036] TiO.sub.2 70-80% Sodium silicate 3.5-10%
Potassium silicate 1.5-6% Sodium carbonate 5-15% Colloidal Silica
2-5% Other components 0-0.5%
[0037] These and other modifications of the discussed embodiments,
as well as other embodiments of the invention, will be obvious and
suggested to those skilled in the art from the disclosure herein,
whereby it is to be distinctly understood that the foregoing
descriptive matter is to be interpreted merely as illustrative of
the present invention and not as a limitation thereof.
* * * * *