Note: Descriptions are shown in the official language in which they were submitted.
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Back round of the Invention
(1) Field of the Invention:
This invention relates to a process and material for treating
metal handling and shaping devices such as steel forging dies and ingot
molds.
(2) Description of the Prior Art:
The present invention relates to a process and material for build-
ing up a penetrating coating on forging dies and the like with a
material that is not affected by the heat of the metal shaping operation
and to which foreign materials will not adhere. The material used in
the process forms a penetrating lubricating adhesive coating on the
metal handling devices.
The prior art comprises my U.S. Patents Nos. 4,187,334 and
4,187,335, issued February 5, 1980.
Summary of the Invention
A process and material for treating metal handling and shaping
devices comprises the coating of the devices as by spraying or other
application of a material which is essentially sub micron sized particles
of graphite in an improved liquid carrier of the extremely fine size of
the submicron s7zed particles of graphite which lowers the surface tension
of the liquid carrier and enables the graphite particles to penetrate the
metal surfaces of the devices and bu;ld up a smooth adhering coating
thereover. The liquid carrier comprises water, an aqueous sodium
silicate solution and hydrochloric acid, a water soluable resin of the
carboxyl group of carboxylic acids, either COOH or C02H and/or composed
of a carboxyl group and a hydroxyl group, ("carboxyl; oxatyl, carboxy,
27 the ac7dic COOH group, it determines the basicity of an organic acid "),
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such as carboxy polymethylene polymers as a dry fluffy acid powder which
is power mixed with the submicron sized graphite particles and the
liquid carrier to obtain a suitable hydrogen bonding in the solution.
Description of the Preferred Embodiment
The material of this invention is particularly suitable for
building up penetrating and lubricating adhesive coatings on metal handling
and shaping devices and comprises between about 5~ to 25% by weight sub -
micron sized particles of graphite, between about 34% to 75% of a solution
of water and sodium silicate (Na2Si307) wherein the sodium silicate is present
at about 40% of the solution, between about 2~ to 10% concentrated hydro-
chloric acid of a 90% purity by weight, between about 33% to 75% of a
solution of water and a carboxy polymethylene polymer resin wherein the
resin is present in amounts between 1% to 10% of the solution by weight,
and between about 15% to 20% water by weight.
The critical particle size of the submicron sized graphite
particles being substantially amicron; less than 5m~or 10-7cm as deter-
mined by electron microscopy. The submicron sized graphite particles are
made by ball milling the finest mesh colloidal graphite particles commer-
cially available for a time sufficient to obtain the desired sub micron
graphite particle size which eliminates the platelets. The carboxy
polymethylene polymer resin powder has a specific gravity of 1.41 and
a bulk density of 13 lbs. per cubic foot. It is available as "CARBOPOL"
from B.F. Goodrich Chemical Co. and low cencentrations mixed with water
as herein disclosed produce a thin gel-like liquid with penetrating and
adhesive qualities.
The liquid carrier as set forth hereinbefore comprises an
effective wetting agent which contributes to the ability of the sub
micron sized particles of graphite to penetrate the metal of the metal
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handling and shaping devices.
The lower percentages of the submicron sized particles of graphite
in the liquid carrier perform most effectively when a number of applica-
tions of the material are applied and when only one or a few applications
of the materials are applied to the metal surfaces, higher percentages
of the subm;cron sized particles of graphite are more desirable.
In either case, the critical particle size of the graphite in
the material penetrates the metal surfaces being treated and builds
up an extremely smooth, slick coating to which the metal being handled
or shaped will not adhere.
In using the material disclosed herein, the process involves
mixing the materials to form a liquid suspension of the submicron sized
particles of graphite and then spraying the same by any suitable spraying
equipment on cleaned metal surfaces of the metal handling and shaping
devices to be treated. One or more coatings are applied as necessary to
build up a smooth unbroken surface of the material on the metal devices
being treated and the material may be applied to the metal surfaces
while they are either hot or cold.
Ingot molds are advantageously treated with the material of the
invention and such treatment expedites the stripping of ingots from
the molds.
The following specific examples of the material have been found
satisfactory:
A. Substantially 8% by weight submicron sized particles of high
purity synthetic graphite, substantially 7% by weight concentrated
hydrochloric acid of substantially 90% purity, substantially 18% by weight
water (H20), substantially 34% by weight aqueous sodium silicate solution
28 wherein the Na2Si307 is present at about 40% by weight of the solution
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and substantially 33% by weight water soluable carboxy polymethylene
polymer resin as a powder wherein the resin is present at substantially
8% by weight of the solution.
B. Substantially 8% by weight submicron sized particles of high
purity synthetic graphite, substantially 7~ by weight concentrated hydro-
chloric acid of substantially 9G% purity, substantially 18% by weight
water (HzO), substantially 67% by weight aqueous sodium silicate solu-
tion wherein the Na2Si307 is present at about 40% by weight of the~solu-
tion .
C. Substantially 8% by weight submicron sized particles of high
purity synthetic graphite, substantially 7% by wight concentrated hydro-
chloric acid of substantially 90% purity, substantially 18% by weight water
(H20~, substantially 67% by weight aqueous solution of carboxy polymethylene
polymer resin as a powder wherein the resin is present at substantially
8% by weight of the aqueous solution of carboxy polymethylene polymer
resin as a powder wherein the resin is present at substantially 8% by
weight of the aqueous solution.
An alternate liquid carrier has been found to produce a suitable
suspension of the submicron sized particles of graphite and substitutes
xanthan gum for the resin, the gum is a nutural high molecular weight
linear polysaccharide, functioning as a hydrophilic colloid to maintain
the submicron sized particles of graphite in suspension and contribute
to the penetrating lubricating adhesive coating as described hereinbefore.
A specific example of such an alternate material follows:
D. Substantially 8% by weight submicron sized particles of high
purity synthetic graphite, substantially 7~ by weight concentrated
hydrochloric acid of substantially 90% purity, substantially 18% by
28 weight water (H20), substantially 67% by weight aqueous solution of
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xanthan gum as a powder wherein the gum is present at substantially
8% by weight of the aqueous solution.
Variations in the amounts of xanthan gum may be used as from 1%
to 19% of the aqueous solution.
; The treatment of ingot molds hereinbefore referred to by the process
and with the material disclosed herein obtains the desired results by
reason of the very fine sized graphite of the material and the manner of
the application. Specifically it is known in the art that molten steel
in an ingot mold takes carbon from the metal of the ingot mold thereby
adversely affecting the interior of the mold by removing the portions
thereof and it is also known that when this occurs the stripping of the
cooled ingot from the mold becomes more difficult because of the interlock
obtained between the solidified metal and the irregular surface of the mold.
By heating an ingot mold the grain structure enlarges and the porosity
of the metal increases and in the present process the material is preferably
applied to the ingot mold when it is heated as by spraying or dipping the
heated mold in the liquid suspension material. Under such conditions
the submicron sized particles of graphite aided by the liquid carrier
penetrates the metal surfaces of the ingot mold which have been previously
cleaned and build up a smooth lubricating and adhering coating which
being largely graphite which is able to supply the carbon that molten
steel usually absorbs from the ingot mold.
Thus the treating material is sacrificed to some degree and the inner
surface of the ingot mild is retained in i-ts desirable smooth condition.
Stripping ingots from the smooth inner surface of the mold is thus consider-
ably expedited and the molds last considerably longer as the carbon from
the metal of the molds is not sacrificed as has heretofore been common in
28 the art.
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