CA2035069A1

CA2035069A1 - Method of warm forming and extrusion of metal and metal working compositions useful therein

Info

Publication number: CA2035069A1
Application number: CA002035069A
Authority: CA
Inventors: Lawrence R. Cohen; Edward J. Gudowicz
Original assignee: Individual
Current assignee: Witco Corp
Priority date: 1990-02-07
Filing date: 1991-01-28
Publication date: 1991-08-08
Also published as: EP0442661A1; JPH04213392A

Abstract

PATENT
Case 890936 METHOD OF WARM FORMING AND EXTRUSION OF METAL
AND METAL WORKING COMPOSITIONS USEFUL THEREIN
Edward J. Gudowicz Lawrence R. Cohen Abstract of the Disclosure Warm forming and extrusion of metals, particularly ferrous-containing metals, at elevated temperatures are disclosed wherein a lubricant composition containing a rare earth metal halide is applied to the surface of the metal prior to the deformation thereof. Lathanum trifluoride and cerium trifluoride are particularly useful. The compositions include: a liquid base, preferably an animal oil, vegetable oil, fat or fatty ester; a viscosity enhancer, preferably an asphaltic material;
a lubricant effective at elevated temperatures; and the rare earth metal halide.

Description

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PATENT
Case 890936 MFT~OD OF WARM FORMING AND EXTRUSION OF METAL
AND MFTAL WORRI~G COMPOSITION5 ~S~ UL T~ER~IN
Ed~ard J. Gudowicz Lawrence R. Cohen ~c~ground of be Invention ~15 The~present inventlon generally reIates to the warm forming and extrusion of metals and to improvements in compositions that can advantageously be used in these me~al working operations. More particularly, this invention is directed to the warm forming and extrusion of metals at temperatures above about 1,100 F. In this regard, an important aspect of the present invention is directed to the use of rare~earth metal halides, such as cerium or~lanthanum trifluoride,~in compositions used in the~warm forming ~;25 ~ and extrusion of steel. ~ ` ~
Warm forming and ext~rusion of metal are procéss~es~generally involving applying a metal working, lubricant composition~;to the~surface~of the metal~prior~to the~deformation ther~e~of. As~such, these composi~ions need to meet~a~variety of requl~rements.~ For exampl~e, i~n addl~tion to lubrication performance,~they must provide protection of~the~metal~surface~from abrasion~and like damage.
Furthermore, they~should be~relatively easy to apply and remove as well as compatible with subse~uently applied coating materials.
Many of these metal~worklng lubricant ~; compositions are homogeneous blends ~ormulated for a specific applica~ion wher~ certain properties are favored over others~but which necessarily are a :

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compromise between conflicting requirements.
Heterogeneous metal working lubricants, such as for example dispersions of lubricant substances in water or other volatile medium are also known. Such heterogeneous lubricants are intended, upon application to a metal workpiece and evaporation of the volatile medium, to leave a continuous homogeneous lubricant film on the metal workpiece.
~o achieve a balance of properties compositions useful in the warm forming of metal, these compositions generally employ a range of oils, waxes, soaps and occasionally polymeric materials, each of which has advantages for specific applications. For example, U.S. Patent No. 4,687,587 to Daglish et al. discloses a lubricant for metal forming comprising discrete particles of a waxy material having a softening point above the metal-forming temperatures in a solid or viscous monomeric organic carrier. Similarly, U~S. Patent No. 3,873,458 to Parkinson discloses a process for cold forming or shaping metal having a resin-oil coating prepared ~rom a dispersion of a copolymer of ethylene and acrylic acid in a lubricant oil.
Correspondingly, U.S. Patent No. 3,167,511 to Crawford et al. discloses the use o chlorinated polypropylene in a lubricating oil as a lubricant for broaching, cutting and rolling metal. These and other lubricants known in the art, however, fail to ~ provide the needed lubrication and surface protection to a metal workplace during the forming or extrusion thereof at temperatures above about 1,100 F.
A precoating is often applied to the me~al before the application of the lubricant. This precoating can contain, for example, lime, zinc phosphate and/or soaps. The use of such a precoating procedure, however, also fails to permit the warm 203,~g~

forming and extrusion of metal at the high tempera-tures desired for the forming and extrusion of numerous metal parts, particularly those made from hard metals.
It has been known for some time that rare earth trifluorides such as lanthanum trifluoride and cerium trifluoride are useful as solid lubricants.
See Rare Earth Fluorides and Oxides--An Exploratory Study of Their Use as Solid Lubricants at Temperatures to 1,800 F. (1,000) C. NASA TND-5301, 1969). Similarly, U.S. Patent No. 4,507,214 to Aldorf discloses the use of rare earth metal halides in a lubricating grease to form a lubricating composition to lubricate wheel bearings. U.S. Patent No. 4,715,972 to Pacholke likewise describes the use of cerium fluoride as one of several solid lubricant particle additives for gear oil. Correspondingly, U.S. Patent No. 3,830,280 to Larsen discloses the use of rare earth halide such as cerium trifluoride or lanthanum trifluoride as lubricants for die casting components. None of these prior art disclosures, however, contains any suggestion of a liquid metal working lubricant composition which is suitable for the warm forming and extrusion of metals at temperatures above about 1,100 F.
It is; therefore an object of this invention to provide a method for the warm formirlg and extrusion of metals at high temperatures, particularly a'c temperatures above about l,lon F.
Another object of this invention is to provide an improved composition useful for the warm forming and extrusion of metals especially at high temperatures.
Another object of the present invention is ~o provide a metal working lubricant composition which is stable and does not decompose at elevated temperatures above about l,100F.

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Another objec~ of this invention is to provide a metal working composition which exhibits improved lubricating characteristics during metal forming and extrusion at high temperatures and also protects the surface of the metal workpiece from corrosion and abrasion.
Another object of the present invention is to provide a composition for the warm forming and extrusion of metals which, in addition to providing the lubrication during the forming and extrusion, continues to provide lubrication after the cooling of the metal.
Another object of the present invention is to provide a high temperature, metal working, lubricant composition that can readily be removed from the metal workpiece after it has been removed from the form.
Other objects of the present invention will become apparent from the ensuing description:
Su-mary of the In~ention The present inqention is directed to improvements in methods for warm forming and extrusion of metals, and to compositions useful thereinO These improvements permit the performance of those metal workiny operations at temperatures of up to about 1,800 F and higher.
In accordance with an important aspect of the present invention, the methods and compositions thereof which are especially useful in warm forming and extruding metal involve the use of a rare earth metal halide in such compositions~ These compositions are liquids having a viscosity less than about 1,500 S.U.S. at 100 F. and include a liquid base, viscosity enhancer increasing the viscosity of -5- ~3~

the composition to between about 150 and about 1,500 S.U.S. at 100 F.; a lubricant effective at elevated temperatures of at least about 400 F., and a rare earth metal halide. Optional components include graphite and/or molybdenum disulfide.

Deta ed Description of _he Present Invention In the process of warm forming metall liquid lubricant is generally applied to the metal by fl~ooding, dipping, brushing or spraying on the part, preferably on a continuous process with the overflow being collected and returned to a central reservoir ; for recirculation. Consequently lt is required that ~he lubricant composition be a liquid. In order that it be abl~ to provide the necessary lubrication it should have a viscosity at 100 F. of between about 150 and about 1~500 S.U.S. Liquid compositions of this viscosity can be pumped and~at the same time furnish the ne ded lubricity. Following;application of the liquid lubricant deformation of th metal workpieve takes place followed~ by removal of the lubricant from the formed product. Often the metal ;
workpiece has a precoating which can contain lime, zinc phosphate~and/or soaps.
It has now been found that the incorporation~of rare earh metal halides into the lubrlcant compositlon lDcteases~the~t~emperature at which metal forming can be effected to about 1,800 F. and higher. This is~a sign1ficant~increase from prior methods which have an upper limit of effective performance of about 1,100 F. Thus, the present process can be performed at~temperatures ~ between about 300 F. and 1~,800 F. For many ; applications, the process is performed at temperatures between about 900 P. and 1,500 F.

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Likewise in the extrusion of metal, liquid lubricant is applied so that a lubricant film is present between the extruded billet and the die. As with warm forming, the viscosity of this liquid composition should be between about 150 and about 1,500 S.~.S. at 100 F.
The presence of a rare earth metal halide in the lubricant composition raises the temperature at which extrusions can be effected in an efficient manner to about 1,800 F. and higher. Prior compositions do not afford the necessary lubrication and metal protection properties at these high temperatures.
Since the methods of warm forming and extrusion of metal allow for the use of temperatures of up to about 1,800 F. and higher, they are particularly valuable in applications using the ferrous metals e.g. steel as well as other metals such as, for example, copper, bronze, brass and aluminum. These methods can be performed at temperatures between about 300 F. and 1,800 F. For the forming and extrusion of many objects, however, temperatures between about 900 F. and 1,500 F. aré
generally employed.
Various liquid compositions can be used to perform the present methods.
One such composition is an oil based composition. A particularly useful oil-based composition comprises the following components:

3~0 1) liquid base 2) viscosity enhancer to increase the viscosity of the composition to between 150 and 1~500 S.U.S. at 100 F.
3) lubricant effective at elevated temperatures of at least about 400 F.

4) rare earth metal halide.
Among optional components of the lubricant , ' : . ' ' - ~3~

composition of this invention are graphite and molybdenum disulfide.
The amount of the li~uid base component in the composition will vary with the specific method being performed and the metal being warm formed or extruded. In general this component constitutes from about 40 to about 90 weight percent of the composition.
Various animal oils, vegetable oils, fats, ~10 fatty esters and mixtures thereof can be used as the liquid base in the present lubricant compositions.
Since this non-petroleum derived material constitutes an important portion of the composition, its `~ selection will necessarily materially effect the physical characteristics of the composition, such as its viscosity and adherence to the metal workpiece.
It is pre~erred that the base be a fat, e.g. a triglyceride. Since triglycerides are made by esterifying the three hydroxy groups of glycerin with fatty acids, often the triglycerides will contain unreacted fatty acids. Fatty acids are in general straight-chain compounds, containing from about 8 to about 18 carbon atoms. A;particularly useful triglyceride, prime burning lard oil, is about 99.5 weight percent trigl~ycerides or related compounds and less than 0~5 weight percent fatty acids. Another useful base is soybean oil having lubricating viscosities from 50~S.U.~S. ~o about 1,000 S.U.S. a~
100 F. Also useful are oleic acid, sul~urize~ lard ~30 oil, marine oil trlglyceride, rape seed oil~ tall oil and paraffin oil.
Since the purpose of the viscosity enhancer is to have a liquid composition with a viscosity of from about 150 to about 1,000 S.U.S. at 100 F., a variety of materials that will increase viscosity of a liquid can be used. A particularly useful viscosity enhancer is aspha1tic material. In .
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"` 2 addition to increasing the viscosity of the liquid base, it also improves the adhesion of the composition and imparts lubricity. In general the viscosity enhancer should be present in an amount of from about 2 to about 25 weight percent of the composition. Other viscosity enhancers that can be used in the present composition are polybutene, aluminum stearate and degras.
Numerous lubricants can be used as the low temperature lubricant composition of the present composition so long as they provide efficient lubrication at a temperature of at least about 400 F. and preferably from about 400 F. to about 1,100 F. A particular class of lubricants of value in the present compositions are sulfur-containing compounds. These lubricants are well known in the art and provide good lubrication properties at temperatures up to about 1,100 F. Sulfurized mineral oil and sulfurized fatty oil are useful for this compo~ent. Examples of other such materials are sulfurized fat, mineralized sulfur, sulfurized hydrocarbons, sulfurized caster oil, sulfurized and - chlorinated oil, and the like.
In general, the sulfurized compound can be present in an amount of from about 5 to about 50 weight percent of the lubricant~composition; however, for most purposes this amount will be between about 10 and about 20 weight percent.
In accordance with an important aspect of the present invention, the metal working lubricant composition includes a rare earth metal halide, preferably fluoride. While other halides such as the chloride are known, available and useful, the fluorides are more preferred. In particular the rare earth trifluorides such as lanthanum trifluoride and ` _9_ cerium trifluoride are preferred. Normally these rare earth metal halides are present in amounts of up to from about 2 to about 30 weight percent or hi~her of the composition with an amount of from about 5 to 10 percent being generally desired. The particle size of the rare earth metal fluoride should be relatively ine.
In addition other solid lubricants can also be included in the present composition as optional components. These solid lubricants which include molybdenum disulfide and graphite can each be present in amounts up to about 10 weight percent of the composition. Their presence can improve the overall lubricity of the composition.
Other optional lubricants that can be included in the present compositions include mica, calcium carbonate and zinc stearate.
The molybdenum disulfide, other optional solid lubricants and the rare earth metal halide can be incorporated as finely divided powders having a particle size for example, from about 0.01 microns to about 100 microns, preferably from about 0.1 to about 45 microns. This invention, however, is not limited to any specific particle size component.
The composition of this invention can be prepared by standard procedures known to the art. In gener~al they can be prepared by mixing the in~redients at a slightly elevated temperature. In order to make a uniform mixture, the rare earth metal trifluoride should be added slowly with mixing. Sufficient mixing, about an hour, should be per~ormed so as to obtain a uniform composition. As an alternative procedure, the composition of the present invention can be prepared by milIing its components.
In addition to oil based compositions, it is often desirable to have available a water-based composition, which can be lower in cost and toxicity.

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Such compositions are composed of the same components as the oil-based compositions; i.e. liquid base, viscosi~y enhancer, lower temperature lubricant effective at temperatures of at least about 400 F.
and rare earth metal halide.
Thus while many of the operative components of the water-based compositions are identical to the components in the oil-based compositions, there are certain distinctions.
As with the oil-based compositions, the aqueous compositions ùtilize a viscosity enhancer.
Generally, this can be any material that increases the viscosity of the composition to between about 150 and 1,500 S.U.S. at 100 F. and is water compatible.
15~ useful materials include cellulose compounds such as sodium carboxymethyl cellulose, glycols, such as diethylene glycol, propylene glycol and butylene glycol, and certain specialized waxes, such as Carbowax 3350.
Since it is more difficult to obtain a uniform mixture in water than in oil, usually there should also be present in the composit~ion wetting agents and dispersants. As is general with water-based compositions containing solid components, the wetting agents and dispersants assist in retaining - particles in dispersion so that the compo ition will be uniform. Numerou~s dispersants and wetting agents are known in~the art.
Optional components in an aqueous composition of the present in~ention include defoamers,anti-microbial agents and corrosion ~ inhibitors. These components can~perform useful ; ~ functions in the present compositions.
Since it is~uneconomical to ship water, rather than prepare compositions containing water, it is often desirable to prepare a concentrate that is shipped to the site of the warm forming or extrusion , ,.

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operation as a concentrate and then dilute it with water to a composition usable in the method for warm forming or extruding metal. In preparing a concentrate that can be diluted to an aqueous composition, a glycol such as diethylene glycol, propylene glycol or butylene glycol may be used in the composition as the viscosity enhancer.
It has been found that the heretofore described lubricant compositions provide excellent lubrication in the warm forming and extrusion of metals at temperatures in excess of 1,100 F. The composition is stable at temperatures higher than 1,100 F. and is stable at 1,800 F. or higher.
Furthermore, the composition protects the metal from corrosion and abrasion and can be easily applied and ; removed by conventional means.
In its application for warm forming and extrusion of metal, the present composition is applied to the metal by conventional methods such as dipping, flooding, brushing or spraying. For best results it is preferred~that the viscosity of the composition be between about 500 and 1,000 S.U.S. at 100 F. This permits reaay~application of the lubricant composition to the metal. Among the metals for which the present composition may be used~are steel, copper, bronze, brass, aluminum and the like.
other metals may also be used in the present method for warm~forming which comprisez applying de~ormation pressure to metal which has been coated with the present composition. This method is especially applicable to metals being formed at temperatures up to and in excess of 1,100 F. and up to about 1,800 F. and higher.
Also the composition of the present invention can be used in the extrusion of metals. In this method, metal, including those previously v ~

described as being applicable for metal forming are coated with the present composition and extruded at temperatures up to about 1,800 F. and higher. The composition of the present invention provides excellent lubrication and protection of the metal from corrosion and abrasion.

The improved high temperature performance of the metal working composition and method of the present invention was demonstrated by comparing the performance of a commercially available metal working lubrlcant ~EXTRUDOIL 519HT), a chemically identical commercial ~etal working lubricant which also includes molybdenum disulfide (EXTRUDOIL 519HT-MOS), and a metal working composition chemically identical to the EXTRUDOIL 519HT-MOS which also included c~rium trifluoride. Both thQ EXTRUDOIL 519HT and EXTRUDOIL 519HT-MOS are available from Witco Corporation, Allied-Relite Div1sion.
The EXTRUDOIL 519HT product is composed of ~1 Lard Oil (a prime burning lard containing 99.5 weight percent glyceride~derivatives and less than 0.5 weight percent free fatty acids), an asphaltic 25~ viscosity enhancer, and a lubricant~constituent made up of a ulfurized fatty oil and a sulfur-cont~aining mineral oil. The EXTRUDOIL 519HT MOS contains the same ingredients as EXTRUDOIL 519HT in the same relative amounts and, in addition includes 10 percent, by weight, of a molybdenum disulfide dispersion. The metal working lub~icant product embodying the present invention contained the same ingredients as the EXTRUDOIL 519HT ln the same relative amounts and, in addition, included 5 percent, by weight, each of a molybdenum disulfide dispersion and cerium trifluoride.

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Each of these metal working lubricants was tested during the extrusion of 15/16 inch diameter 1050 steel wire to form cam shaft lobes with a National Machinery Model 1000 extruder having a carbide die. The die was flooded with the lubricant which was continuously recirculated and the extrusion temperatures incrementally raised while observing the performance of the lubricant.
The EXTRUDOIL 519HT metal working lubricant which did not contain molybdenum disulfide or a rar~
earth metal halide worked well within the temperature ;~ range of 800-900 F. Increasing the temperature beyond 900 F. decomposed the composition and at ` ~ these higher temperatures there was insufficient lubrication to form the lobe.
The EXTRUDOIL 519HT-MOS metal working lubricant containing molybdenum disulfide but not containing a rare earth halide permitted formation of the lobe at temperatures between about 1,000 F. and ~0 1,100 F. Increasing the temperature beyond 1,100~F. decomposed the composition and caused insufficient lubrication to form the lobe.
The metal working lubricant which contained cerium trifluoride permitted formation of the lobes at temperatures of 1,500 F. and above without any observable breakdown of the metal working lubricant.
Thus the present compositions can be u~sed effectively at temperatures no~ readily lubricated by prior petroleum-based compositions. This permits the ready formation of warm molded and extruded parts efficiently at temperatures of about l,500 F. and higher.
The following examples are illustrative of other compositions which are within the scope of the present invention. Examples 2-9 describe oil based compositions; Examples 10-13 describe aqueous compositions of the present invention; and Examples 14 and 15 describe concentrates which are readily dispersible in water.

ComPonent ~ ht Percent #1 Lard Oil 54 Asphaltic Type Material 14 Sul-Perm 18* 11 Mineralized Oil 6 Containing Sulfur Molydenum Disulfide 5 Dispersion Graphite 5 Cerium Trifluoride 5 : 20 *Sul-Perm 18 is a sulfurized fatty oil having a viscosity at 100 F. of approximately 2,800 S.U.S. to 3,300 S.U.S.; a flash point of 450 F.; a fire point of 490 F.; a weight of : 8.4 pounds per gallon; and containing 17 :25 weight percent sulfur.

: Example 3 Component Weight Percent :
~1 Lard OiI 40 ~ Asphaltic Type Material 8 : Sulfurized/Chlor~nated Oil 29 : Molydenum Disulfide :12 Dispersion Lanthanum Trifluoride11 Exampl e 4 Component Weiqht Percent Marine Oil 56 2 ~

Example 4 (CONT.) Coml~onentWeight Percent Asphaltic Type Material 15 Sulfuri2ed Caster Oil 19 Graphite 5 Cerium Trifluoride 5 Example 5 ComponentWei~ht Percent Soybean Oil 70 : ~ Aluminum Stearate 4 Sulfurized Fat 12 Mineraliæed Oil 10 ; 1~5 ~ Containing Sulfur Zinc Stearate 2 ~ : Ceri~m Trifluoride 2 : ~ Example 6 ComponentWeiqht Percent Soybean Oil 65 Degras : 4 Sulfurized Sperm Oil 12 ; Mica 5 : :25 : Cerium Trifluoride: 14 ~ ~ Exampl e ?
: Component :Weiqht Percent ~ Rape~Seed Oil ~ 60 ~:
: 30 : Polybutene 2Q
: Pearsall 0~ 319* 10 Lanthanum Trifluoride 10 ~ *Pearsall OA 319 is a synthetic sulfurized : 35 sperm oil replacement containing about 17~.8 weight percent sulfur having a viscosity of 270 S.U.S. at 210 F. and~3tOOO, S.U.S~ at 100 F. and~weighing 8.6 pounds per gallon.

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, Example 8 Component Weiqht Percent Tall Oil 58 Asphalt 5 Pearsall OA 319 15 Base 380* 5 Graphite 3 Lanthanum Trifluoride 14 *Base 330 is a sulfurized hydrocarbon having a : sulfur content of 38 weight percent, weighing 9.2 pounds per gallon, having a viscosity at 100 F. of 420 S.~.S. and 60 at 210 F.

15 : ExamPle 9 Component ~ Weiqht Percent Sulfurized Lard Oil ~ 65 Asphaltic Type Material 15 Di-tert-nonyl Polysulfide 6 Pearsall OA 377* 5 Calcium Carbonate 3 ; Cerium Trifluoride 6 : *Pearsall OA 377 is a sulfurized olefinic 25 : hydrocarbon:containing typically 36 weight percent sulfur and having a viscosity at~51 S.U.S. at 210 F. ~and 245 S.U.S. at 1:00 F.
and weighing 8.5:8: pounds per gallon. It is completely soluble in naphthinic and paraffinic oils and has a flash point of 335 F~ and a fire point of:360 F.

~: : Exam~le 10 Component Weig~
Water 40 '. ' ,' ~' "' , '' ' , ~3~

xam~ e _ 0 (CONT. L
mponent Weiqht Percent Diethylene Glycol Carboxymethyl Cellulose 0.5 Sodium Hydroxide (50~) 5 Adipic Acid 5 Molybdenum Disulfide 18.5 Dispersion Cerium Trifluoride 30 ExamPle ll _omponent Weiqht Percent Water 60 Diethylene Glycol 2 Carboxymethyl Cellulose Sodium Hydroxide 15 Adipic Acid 10 Molybdenum Disulfide 5 Dispersion Cerium Trifluoride 7 Example 12 : Component Wei~ht Percent : 25 ~ : Water 40 Diethylene Glycol 5 Borax ~ l :
Tripolyphosphate 20 N-lO (surfactant) 30 : Carboxymethyl Cellulose Molybdenum Disulfide 7 : Disparsion Cerium Trifluoride 2S
:: :
Example 13 _o~ponent Weiqht Percent Water 60 ~18-Example 13 tCONT.) Component Weiqht Percent Diethylene Glycol lO
Borax 2 Tripolyphosphate lO
N-10 tsurfactant) Carboxymethyl Cellulose 5 Molybdenum Disulfide 6 Dispersion Cerium Trifluoride 6 : Exam~le 14 Component Weight Percent Borax 38 Dispersant Carboxymethyl Cellulose Adipic Acid 5 Sodium Hydroxide Granules 5 Graphite 30 Molybdenum Disulfide lO
: ~ Dispersion Cerium Trifluoride 10 : Exa~ple 15 25:: : Component Weight Percent Borax 30 Dispersant 0.5 Carboxymethyl Cellulose 0.5 : Adipic Acid 10 Sodium Hydroxide Granules 5 : ~ Molybdenum Disulfide 10 : Dispersion Graphite 19 : Cerium Trifluoride 25 ~35 It will be understood that the above-described embodiments of the present invention are .
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merely illustrative of the present invention and that modifications thereto may be made by those skilled in the art without departing from the sp.irit and scope thereof.

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Claims

1. In the method of warm-forming metal wherein a lubricant is applied to the surface of a metal workpiece which is thereafter deformed, the improvement wherein said lubricant includes a a rare earth metal halide.

2. The method of claim 1 wherein said lubricant is a liquid.

3. The method of claim 1 wherein the rare earth metal halide is present in an amount of up to about 30 weight percent of the lubricant composition.

4. The method of claim 1 wherein the rare earth metal halide is a lanthanide halide.

5. The method of claim 1 wherein the rare earth metal halide is cerium halide.

6. The method of claim 4 wherein the rare earth metal halide is lanthanum halide trifluoride.

7. The method of claim 5 wherein the rare earth metal halide is cerium trifluoride.

8. The method of claim 7 wherein the cerium trifluoride is present in an amount of up to about 10 weight percent of the lubricant composition.

9. The method of claim 1 wherein the lubricant composition also contains up to about 10 weight percent graphite.

10. The method of claim 1 wherein the lubricant composition also contains up to about 10 weight percent molybdenum disulfide.

11. The method of claim 1 wherein said metal is a ferrous metal.

12. The method of claim 1 wherein the metal is steel.

13. The method of claim 1 wherein the temperature at which said metal workpiece is deformed is between about 300° F. and about 1,800° F.

14. The method of claim 1 wherein the temperature at which said metal workpieve is formed is between about 900° F. and about 1,500° F.

15. In the method of metal extrusion wherein a lubricant is applied to the surface of the metal being supplied to an extrusion die, the improvement wherein said lubricant includes a rare earth metal halide.

16. The method of claim 15 wherein said lubricant is a liquid.

17. The method of claim 15 wherein the rare earth metal halide is added in an amount of up to about 30 weight percent of the lubricant composition.

18. The method of claim 15 wherein the rare earth metal halide is a lanthanide halide.

19. The method of claim 15 wherein the rare earth metal halide is a cerium halide.

20. The method of claim 18 wherein the rare earth metal halide is lanthanum trifluoride.

21. The method of claim 19 wherein the rare earth metal halide is cerium trifluoride.

22. The method of claim 21 wherein the cerium trifluoride is present in an amount of up to about 10 weight percent of the lubricant composition.

23. The method of claim 15 wherein the lubricant composition also contains up to about 10 weight percent molybdenum disulfide.

24. The method of claim 15 wherein the lubricant composition also contains up to about 10 weight percent graphite.

25. The method of claim 15 wherein the metal is a ferrous metal.

26. The method of claim 15 wherein the metal is steel, copper, bronze, brass or aluminum.

27. The method of claim 15 wherein the extrusion temperature is between about 300° F. and about 1,800° F.

28. The method of claim 15 wherein the extrusion temperature is between about 900° F. and 1,500° F.

29. A liquid metal working lubricant composition having a viscosity less than about 1,500 S.U.S.
at 100° F. useful in the warm forming and extrusion of metal at temperatures up to about 1,800° F., said lubricant composition comprising: a liquid base; a viscosity enhancer; a lubricant effective at elevated temperatures, and a rare earth metal halide.

30. The composition of claim 29 wherein the liquid base is present in an amount of from about 40 to about 90 weight percent of the composition; the viscosity enhancer is present in an amount of from about 2 to about 25 weight percent of the composition; the lubricant effective at elevated temperatures, is present in an amount of from about 5 to about 50 weight percent of the composition, and the rare earth metal halide is present in an amount of from about 2 to about 30 weight percent of the composition.

31. The composition of claim 29 which also contains up to about 10 weight percent of molybdenum disulfide.

32. The composition of claim 29 which also contains up to about 10 weight percent of graphite

33. The composition of claim 29 wherein the liquid base is an oil

34. The composition of claim 29 wherein the liquid base is water.

35. The composition of claim 29 wherein the liquid base is selected from the group consisting of animal oils, vegetable oils, fats, fatty esters and mixtures thereof.

36. The composition of claim 29 wherein the viscosity enhancer is asphaltic material.

37. The composition of claim 29 wherein the lubricant contains sulfur.

38. The composition of claim 29 wherein the sulfur containing lubricant is selected from the group consisting of sulfurized mineral oil, sulfurized fatty oil, elemental sulfur and mixtures thereof.

39. The composition of claim 29 wherein the rare earth metal halide is a fluoride.

40. The composition of claim 39 wherein the rare earth metal halide is lanthanum trifluoride.

41. The composition of claim 39 wherein the rare earth metal halide is cerium trifluoride.