EP0617118A1

EP0617118A1 - Forging lubricant composition and process

Info

Publication number: EP0617118A1
Application number: EP94301993A
Authority: EP
Inventors: Anthony Peter Willoughby
Original assignee: Acheson Industries Inc
Current assignee: Acheson Industries Inc
Priority date: 1993-03-23
Filing date: 1994-03-21
Publication date: 1994-09-28
Also published as: CA2116880A1; JPH0770586A; AU5763694A

Abstract

A novel forging lubricant composition containing: suspended polypropylene having an average molecular weight between about 500 and about 300,000, an emulsifying agent to assist in maintaining materials of the composition in emulsified form, a thickening agent to assist in maintaining the composition at a suitable viscosity, a preservative agent, other additives, and the balance of a liquid carrier medium.

Description

Background Of The Invention

Forging of metals, as relates to this invention, is the process whereby solid metal is deformed under pressure by means of dies or tools, in one or several stages resulting in the final shape and size of the metal conforming to that of the dies or tools, or a cross section thereof. Such processes are described as hammer or drop forging or stamping, press forging, warm forging, cold forging, isothermal forging, hot or warm forwards and/or backwards extrusion, cold forwards and/or backwards extrusion, hot or warm or cold drawing, hot or warm or cold pressing and hot or warm or cold deep drawing. Forging or extrusion operations are generally described as falling into one of three broad areas, namely hot forging, warm forging and cold forging. The term "forming" is synonymous with "forging" in the following context.
Hot forging or forming generally describes processes of deformation of a metal workpiece pre-heated to a temperature where it is ductile and malleable and such that the deformation will not work harden the metal. Typically for example, these temperatures range in the case of ferrous alloys and steels from 760°C to 1350°C, and for aluminum alloys from 315°C to 500°C.
Warm forming takes place at temperatures below the normal hot-working ranges and offers certain advantages over both hot and cold forming, in that there can be significant reductions in forming loads as compared with cold forming, while the problems of scaling, due to oxidation, and decarburization of steels encountered in hot forging, can be eliminated. Lubrication can be more effective than with hot forging and the dies can be made to higher tolerances producing forgings of greater accuracy, thus reducing the need for final machining operations. Typical temperatures for warm forging steel alloys are in the range of 650°C to 850°C.
Cold forging is the forming of metal at ambient temperatures by force between dies or by pushing or drawing through dies in the case of extrusions. With little thermal change in dimensions, lack of scale or oxide formation and no decarburization of steels occurring, cold forming can produce components to a high dimensional precision.
In all the above forging processes a lubricant is required to reduce friction between the workpiece and the die. Reduced friction means that the forging loads will be lowered, because the metal can flow and conform to the die shape more easily, wear on the die and tools will be reduced, giving longer lives and lower operating costs and, just as importantly, the forging can be more easily released from the dies.
In the case of hot forging, the oldest of the forging methods, in the past the traditional die lubricants were heavy mineral oils, sometimes with added damp wood sawdust and/or graphite powder thrown onto the dies or mixed with the oil. Later the use of tailor made oil based compositions containing various additives such as colloidal graphite became common place. Oildag™ from Acheson Colloids Co. is one such product.
Still later, for reasons of health and safety, cleanliness and more acceptable working environments, these oil based products were largely replaced by water based lubricants, removing the side effects of contaminating the working environment with large amounts of smoke and oil fumes and the associated health hazards of constant contact with mineral oils.
Water based lubricants usually consist of a finely divided solid lubricant, such as graphite, dispersed in water together with necessary dispersing agents and film forming binders. Other inorganic lubricating or refractory solids have been utilized as well as soluble inorganic salts and soluble organic substances. These lubricants, usually applied by spray or brush on to the hot dies prior to forging, by their nature give a dry coating of solid lubricant or parting agent on the die surface. All surfaces that require lubrication must be coated at the time of application of the lubricant as the dry coatings do not run, spread or creep in the same manner of an oily fluid coating. Various additives in the water based formulations alter the adhesion and abrasion resistance of the coatings to ensure optimum performance for each particular type of forging operation.
Although water based die lubricants based on the latter technology are very successful for most applications in hot and warm forging, there are some forging operations where an oil containing lubricant is necessary. In general the excellent high temperature wetting and coating properties of oils based lubricants, combined with the fluidity and self healing properties of a mobile film of oil carrying the dispersed solid lubricant, give superior performance to the dry coatings deposited by water based products.
As a compromise, where the presence of some oil is essential for adequate lubrication, the practice of using an aqueous emulsion of mineral oil, perhaps containing a solid lubricant or, of adding to a water based product mineral oil in the form of an aqueous emulsion, has proved technically successful. The disadvantages of mineral oil usage, subsequent smoke, smell and fumes, although proportionately reduced from that of neat oil, are still present.
Another variation on the water based lubricant theme is provided by so called "non-pigmented" lubricants, which in practice means "graphite free" products. These are an attempt to further improve the working environment by removing the source of black graphite dust that inevitably collects and contaminates the areas around machines where graphite containing lubricants are in use. Without graphite or the presence of alternative solid lubricants, these non-pigmented products provide little extreme pressure lubrication under forging conditions, but mainly rely on assisting release of the forging from the dies by acting as a parting agent. Use of non-pigmented water based lubricants is thus limited to forgings that require little lubrication to assist metal flow and/or, where die lives or tolerances are not very important.
Other attempts to improve the lubricity of the dry films deposited by water based lubricants on the hot dies have included additions of inorganic salts with selected melting points, and the use of various high melting point waxes of natural, paraffinic and polyethylene types in the form of aqueous emulsions, have met with limited success.

Summary Of The Invention

From a composition aspect, the invention concerns a novel water based forging lubricant composition, comprising in weight percent: (a) about 1% to about 40% polypropylene having an average molecular weight between about 500 and about 300,000, (b) zero to about 8% of emulsifying agent to assist in maintaining materials of the composition in an emulsified form, (c) zero to about 5% of thickening agent to assist in maintaining the composition at a suitable viscosity, (d) zero to about 3 % of a preservative agent, (e) zero to about 45 % of an additive selected from at least one material of the group consisting of graphite powder, boron nitride, polytetrafluoroethylene, talcum powder, naphthalene sulfonate, diammonium phosphate, sodium silicate, depolymerized rubber, dextrin, terephthalic acid, zinc stearate, and molybdenum disulfide, (f) about 0.05% to about 10% by weight of a soluble alkaline agent to maintain the pH of the composition within the range of about 8 to about 11, and the balance water.
In another aspect the invention concerns a novel forging lubricant composition, comprising in weight percent: (a) about 1% to about 30% dispersed polypropylene having an average molecular weight between about 500 and about 300,000, (b) zero to about 8% of emulsifying agent to assist in maintaining materials of the composition in an emulsified form, (c) about 50% to about 92% liquid carrier for the composition, (d) about 0.1% to about 40% of an additive selected from at least one material of the group consisting of molybdenum disulfide, graphite, boron nitride, zinc stearate, a resin binder, and a pH control agent.
It should be understood that the invention described herein relates to forging lubricant compositions, and has no application to compositions used for metal drilling, turning, broaching, pipe rolling, metal machining, or metal cutting.

Technical Advantages Of The New Compositions

It has been found that water based forging lubricant compositions can be formulated so as to retain all the advantages of being water based but giving improved performance levels approaching that of mineral oil containing lubricants, without suffering the attendant disadvantages of using mineral oils. Further, that such products can be formulated with or without graphite or other solid lubricants present, giving increased lubricity over equivalent present state of the art graphite and/or other solid lubricant containing, or non-pigmented, water based forging lubricant formulations.
Also, that non-aqueous forging lubricants can be formulated giving enhanced lubrication when applied to dies which are heated to temperatures above which lubrication provided by mineral and synthetic oil based products becomes marginal due to rapid volatilization and decomposition of the oils.
The above improvements and benefits are obtained by the inclusion of solid polypropylene polymer dispersed in the form of a finely divided powder or as a stable aqueous emulsion, into aqueous or non-aqueous forging die lubricants formulations.
At ambient temperatures the polypropylene is a solid material, having none of the disadvantages of mineral or other oils, synthetic or natural, being non-toxic and resistant to microbiological attack. At temperatures above 161°C and below 460°C for time intervals associated with forging techniques, the polypropylene melts to form an oily fluid that has excellent lubricity properties, especially when in conjunction with finely divided solid lubricant particles such as graphite.
With extended time and heating, polypropylene homopolymers and copolymers thereof, degrade to low molecular weight polymers that do not solidify on cooling, thus avoiding build up of solid residues on dies and workpieces, as could occur if alternative solid polymeric materials were utilized.
Thus, by inclusion of finely dispersed polypropylene, forging die lubricants can be formulated as water or other fluid carrier based products; so that once the carrier fluid has evaporated after application of the product to the dies, as is normal practice in the forging art, the resulting lubricant coating, under the action of heat and applied pressure of forging will, as the polypropylene polymer melts, behave in a manner similar to oil based or oil containing die lubricants. A mobile fluid film is formed, containing the solid lubricant or other additives if present in the formulation, providing the necessary lubrication and release properties essential for good metal flow and dimensional accuracy of the forging.
Being a fluid film the lubricant can move with the metal flow. Compared to dry lubricant coatings, a fluid film gives lower friction between the workpiece and the dies and will to some extent be self healing if the lubricant film is momentarily breached at some point. With dry lubricant coatings such a breakdown will result in further damage to the coating as the metal continues to slide over the rupture. Die wear occurs rapidly under such conditions. This behavior is well recognized in the forging industry.

Cold Forming

Cold forming operations are a special case where the lubrication is an integral part of the process. Without lubrication only the very simplest forming would be possible. The most widely used lubricants, where there is a large amount of metal deformation, are metallic soaps combined with chemical surface treatments such as phosphating of various kinds depending on the metal and alloy to be formed. Dry films of molybdenum disulfide coatings on their own, or over phosphated surfaces, are also used. For cold drawing and pressing of sheet metals, lubricants used include oils, waxes, plastic sheets bonded to the metal or dry film lubricants containing solid lubricants such as P.T.F.E., graphite, molybdenum disulfide, metallic soaps, or any combination thereof.
In nearly all cold forming operations the lubricant is applied to the workpiece and not onto the dies or tools. The lubricant coating must be strongly adherent to the workpiece and also be flexible to stretch with the metal as it is deformed.
Cold forming dry film lubricant compositions containing polypropylene have been discovered to show benefits of reduced friction by virtue of the polymer becoming semi-fluid under the instantaneous pressure and skin temperatures encountered during the forging process at the contact points between the workpiece and the dies. As the surface area increase of the workpiece occurs at these points where the coating is mobile, the semi-fluid coating will stretch and retain adhesion on release of the pressure and subsequent cooling and freezing of the film It is therefore believed that such compositions could compete with the traditional lubricants such as graphite, molybdenum disulphide and soaps usually combined with a phosphate pretreatment, showing substantial savings in process costs.

Problems Solved By Usage/Application Of The New Compositions

a) The prior water based, oil free, forging lubricants generally had adequate lubrication performance for most forging operations, but any improvement in lubricity would be an advantage as lower press loads and longer die lives should result. Apart from such improvements there are forging operations where dry, oil free, lubricants do not have the necessary properties, and lubricants containing oils must be utilized. It has been unexpectedly discovered that forging die lubricant compositions can be formulated with polypropylene to have similar performance characteristics to those containing mineral, or other oils, without having the associated disadvantages of toxicity, fumes, smoke, and disposal of waste effluent problems. Preferably the polypropylene is in the form of a dispersion of finely divided powder in a liquid carrier or as an aqueous emulsion. Additionally in some countries, especially in Europe, importation of mineral oil containing products invokes a high level of import duty being levied. The new compositions avoid all these disadvantages.
b) It is most economical to supply forging die lubricants as concentrates for dilution at the point of use by the customer. Oil based product concentrates need to be diluted with a compatible solvent or diluent, which adds extra costs to the process. Water based die lubricant concentrates need only to be diluted with water before use, a significantly cheaper commodity without the hazards of flammability, toxicity and special storage requirements. Therefore a water based lubricant, giving the same order of performance as oil based ones, will show considerable advantages in cost savings.
c) Tests have shown that compared to water based dry film lubricants used as forging lubricants, the new compositions have significantly increased lubricity and reduce the friction between the work piece and dies, resulting in markedly increased speeds of metal flow. The extent of the improvements are difficult to quantify under commercial forging conditions, but in some cases such excellent lubricity was obtained that the forging press loads have had to be reduced to a minimum to prevent damage to the press itself. In one test, when forging an aerofoil section gas turbine blade component in a titanium alloy, the improvement in lubricity was so marked that the metal moved far too quickly and too far between the dies, causing stress fractures in the forging. In this case the amount of polypropylene in the formulation would have to be lowered compared to the graphite content to reduce the lubricity of the product to suit the application. Certain tests and evaluations which were conducted are described herein below.

PART A. -- STEEL GEAR WHEELS FORGING TESTS

In this test involving hot forging of steel gear wheels for automotive use, an aqueous graphite containing die lubricant of the same basic formulation as example composition No. 5 (but not containing any polypropylene solids) was first used. Good lubricity, release and surface finish was achieved but some build up of residues occurred in the dies in the impressions of the gear teeth. This resulted in loss of dimensional accuracy. Next a die lubricant of the basic formulation of example No. 4, but not containing any polypropylene solids, was tested. This time no build up of residues in the dies occurred, but the lubricity and release properties were inferior to those of the previous composition.
A further trial was then conducted, using for the die lubricant composition example No. 4 containing the emulsified polypropylene solids. This die lubricant gave excellent lubricity, release and surface finish with no evidence of build up in the dies. Dimensional accuracy of the forged gear wheels was maintained throughout the test and the forgings were visibly cleaner than those made with the die lubricants not containing the polypropylene solids.
The above tests were done on a 1300 tonne and a 1500 tonne Ajax crank press. The dies were of a high precision type and fully closed on forging allowing no flash to escape. The billets were of an unspecified steel alloy, cut to very accurate weights, so as just to fill the die without any tendency to form flash. On the 1300 tonne press were made precision finished gear wheels, and on the 1500 tonne press were made gear wheel blanks for finishing by a machining operation.

PART B. -- TURBINE BLADE FORGING TEST

In this test, trials were conducted to determine the effect on lubricity of an addition of emulsified polypropylene to graphite in water die lubricants. The trials involved the hot, precision forging of aerofoil section turbine blade for gas turbine aero engines. In this process the aim is to forge the blades to finished dimensions and shape, with minimal finishing operations to the forged components.
The die lubricant normally used is Acheson product Dag 2885, a semi colloidal dispersion of 4% graphite in water, applied by hand spraying the dies before each forging is made. The die lubricants tested were products APW 4011A, APW 4011B and APW 4011C, containing respectively 5%, 3.5% and 2% semi-colloidal graphite dispersed in water. These die lubricants were test against product APW 4012A which is the same as example composition No.2 (being APW 4011C) with added polypropylene emulsion; and contains 2% graphite plus 2% polypropylene solids.
With precision forging of this type, the lubricity provided by the die lubricant is critical in achieving satisfactory results. Insufficient lubrication will result in oversize forged parts, that is blades that are thicker than the designed tolerance. This is because if the lubrication is poor, high friction between the dies and the billet will retard the sideways spread of the metal as the press closes. This result is often also characterized by evidence of incomplete press closure, lack of flash and incomplete die filling.
Conversely, use of a die lubricant that is too lubricous will be detrimental, as in such cases on closure of the dies the metal flow is too great, causing poor surface finish with open grain defects and undersize forgings; and excessive flash and cracks in the forging can be present. There is also a danger of causing damage to the press due to the dies bottoming.
The effects of varying lubricity of the die lubricants are readily observable in this type of forging, making the process ideal for rapid assessment of the comparative lubricity of different die lubricant compositions. Note that the most lubricating composition found in this test may not necessarily be suitable in practice for the precision forging process, as explained previously.
Two trials were carried out on two different presses, using different steel alloys and making different turbine blades.

Trial 1

This trial was conducted on a 1000 tonne Hasenclever screw press, forging a double ended turbine blade in Jethet M152 12% chrome steel for the Rolls Royce RB 211 engine. The billets were preheated to 1140°C prior to forging. Die temperatures were around 180°C.
For this test the die lubricants were all diluted with 2 parts by volume of water to 3 parts by volume of lubricant before spraying.
The results are summarized as follows:

Trial 2

A Hasenclever 800 tonne screw press was used to forge a single ended turbine blade in Inconel 718 high nickel content steel. The billets were preheated to 1020°C and the dies ran at about 180°C. For this trial the die lubricants were applied without any dilution with water.

The results are summarized as follows:

Die Lubricant	Graphite Content %	Polypropylene Content%	Forged Dimensions	Forged Appearance	Comments
APW 4011A	5.0	-	Slight Undersize	Some open grain	Black residue on blade
APW 4011B	3.5	-	O.K.	Slight open grain	Black residue on blade
APW 4011C	2.0	-	O.K.	O.K. good finish	Slight residue
Example Composition of this Invention (No. 2)	2.0	2.0	Very Undersize	Bad open grain. Heavy flash.	No residues. Too lubricous.

The results from both trials show the markedly increased metal movement obtained when using the example composition No. 2 containing emulsified polypropylene as the die lubricant, when compared to similar lubricants without any polypropylene in their compositions.
Other studies have shown that inclusion of polypropylene in various compositions reduces friction significantly under simulated forging conditions as can been seen from Ring Compression Tests that have been conducted, as set forth below.

PART C. -- TEST EVALUATIONS USING THE RING COMPRESSION TEST

To further evaluate this invention, it was decided to add polypropylene emulsion to two standard forging products, which would then be measured under controlled conditions on the Ring Compression Test. This test simulates regular 'hot' forging conditions, while measuring lubricity in a reproducible manner. A sketch of the actual test 'ring' and its holder are shown in Figure 1.

I. Test Methods

The test rings (OD=3", ID=2", H=1") were machined from 8620 steel. The dimensions of ten rings were measured; both the ring diameters and heights were within + 0.005 inches of the nominal values. See FIGURES 1 and 2.
The rings were induction heated to the forging temperature in nitrogen atmospheres. In order to obtain uniform heating, the rings were mounted on 3" diameter cylinders with one end machined to a 2" diameter to accommodate the rings (Figure 1). The forging temperature, controlled via an infrared thermometer, was monitored and found to be in the range of 1850 to 1900°F.
Two sets of flat insert dies were mounted on the slide and bed of a 1600 tone maxi (mechanical) press. The dies were preheated by both gas flames and contacts with heated cylinders. Measurements via contact thermometers during forging periods indicated die surface temperatures in the range of 200 to 250°F. The lubricants were applied by spraying both the slide and bed die insert surfaces. On exiting the induction heating coils, the rings were removed from their positions on the mounting cylinders (Figure 1) and were forged to height reductions of 23.5% and 39%. The die surfaces were cleaned by washing and/or abrading between each lubricant test series.
Measurements of the inner ring diameters (Figure 2) and ring heights were performed on a Brown and Sharpe Microval measuring instrument. The ring diameters were not always as shown schematically in Figure 2. Differential cooling of the ring surfaces contacting the top and bottom dies resulted in unequal ring diameters (TOP D not equal to BOT D; the coolest surface would have the smallest diameter).

II. Test Result Calculations

The forged heights were measured and averaged to determine the mean % height reduction (= 23.5% and 39% respectively) and to determine the ranges in the forged heights (+.005 inches). For each lubricant, all of the ring diameter measurements at the mid-height (MH D), top (TOP D), and bottom (BOT) were averaged to give the AVERAGE OF ALL DIAMETERS.
The larger the inner ring diameter is after forging, the smaller is the die/workpiece interface friction.
The rings were machined from 8620 steel, within an inner diameter of 2.000 ± 0.050 inches. These rings were preheated to 1900°F and then forged in a 1600-ton mechanical press, such that each ring was reduced in height by 23.5%. At least three replications were done for each type of lubricant, yielding a reasonable statistical sampling. Using this well-established method, the increase in the inner diameter of each ring can be directly correlated with interfacial friction between the tool and work-piece.

Series 1

The first series of tests were done in the following manner: two commercial forging lubricants products were chosen, DF-1001 and DF-31 (these are Acheson products Deltaforge 1001 and Deltaforge 31). DF-1001 is non-graphite material based on the salt of a carboxylic acid; while DF-31 is primarily graphite in water.
To each of these materials, there was added polypropylene emulsion such that the polypropylene comprised 25% by weight of the final product solids. These were designated as DF-1001PP and DF-31PP, respectively. Each of the modified products was then submitted for test, together with it's 'parent' product as a control. All products were diluted 1:4 with water and sprayed onto the dies, after which the rings were deformed in height by 23.5% The specimens were then cooled and measured. The average results were as follows:

Product Inner Diameter @ 23.5% Reduction Coefficient of Friction Calculated @ 23.5%

DF-1001 2.088 in. 0.2010

DF-1001PP 2.096 0.1970

DF-31 2.054 0.1650

DF-31PP 2.162 0.1567
It was apparent that the products of DF-1001PP and 31PP gave a measurable decrease in frictional forces. Further, the parts made with polypropylene added had a bright, glossy surface; while the rings formed without polypropylene did not have this improved appearance.

Series 2

To further test this inventive composition it was decided to run a more difficult forging; this time, the rings were to be compressed by 40% of their original height. In this series, due to time constraints, only the DF-31 and it's analog were tested. The same sequence was followed, except that the press spacing was reduced to give a 40% reduction. The results are tabulated below:

Product Inner Diameter @ 40% Reduction Coefficient of Friction Calculated @ 40%

DF-31 1.970 0.1640

DF-31PP 2.111 0.1530
Again, very significant beneficial effects were generated by the addition of polypropylene emulsion. Lubricity was enhanced, while the appearance of the finished ring was glossy and clean. There could be no further doubt regarding the very significant technical advantages and benefits of this invention.

Basic Ingredients Required In The New Compositions

a) The essential ingredient is polypropylene homo or copolymers. Preferably the polypropylene is in the form of a finely divided powder or an aqueous emulsion. Examples of the aqueous Emulsion are Emrel 7, from Hickson and Welch Co., available as 30% and 40% solids content versions and, Poly Emulsion 43N40, a 40% solids content polypropylene emulsion from the Chemical Corporation of America (Chemcor).
Particle size: suitable finely divided polypropylene powder for incorporation in to aqueous and non-aqueous based products should preferably have a maximum particle size diameter not exceeding approximately 75 microns. More preferably the powder should have a particle size not exceeding approximately 20 microns with a mean size diameter of approximately 10 microns. For aqueous dispersion the powder should ideally have a mean maximum particle size of approximately 2 microns with the maximum not exceeding approximately 5 microns.
b) With the polypropylene may be included in the compositions:
- i. Solid lubricants, as, for example but not limited to, graphite, boron nitride, molybdenum disulfide, polytetrafluoroethylene (PTFE) and the like.
- ii. Wetting and dispersing agents, as, for example but not limited to, alkyl naphthalene sulphonates, alkyl lignum sulphonates, surfactants including non-ionic, anionic and cationic surfactants, polysaccharides, cellulosic derivatives, and the like.
- iii. Refractory inorganic dispersed solids, for example but not limited to, talcum, mica, clays, chalks, etc.
- iv. Suspending agents and thickening agents, for example but not limited to, organo modified clays, soluble organic polymers, soluble thixotropic polymers and the like.
- v. Binders and film forming ingredients, for example but not limited to cellulosic derivatives, polysaccharides, acrylic polymers and the like.
- vi. Inorganic salts for example but not limited to, alkali silicates, alkali phosphates, poly phosphates, alkali carbonates, borates, nitrates and the like.
- vii. Organic acids and organic salts, for example but not limited to, polycarboxylic acids and their alkali salts.
- viii. Dyes and pigments for coloration, visual application aids and cosmetic additives.
- ix. In the case of water based compositions, preservatives.
- x. Carrier base fluids such as but not limited to, water, mineral oils, natural oils, synthetic oils, glycols, mineral solvents, hydrocarbon solvents and the like.

BEST MODE OF CARRYING OUT THE INVENTION & DESCRIPTION OF PREFERRED EMBODIMENTS

The polypropylene for this invention should, in general, have an average molecular weight between about 500 and 300,000; and preferably between about 2500 and about 10,000; with most preferred results being obtained using polypropylene having an average molecular weight of between about 4,000 and about 5,000. So called crystalline polypropylene is ideal, for example having a relatively sharp melting point (for example in the range of approximately 125-180°C). Typically the polypropylene is used in the composition in the form of an aqueous emulsion such as Emrel 7 (40% solids) obtained from Hickson & Welch Ltd. Other types of polypropylene may also be used, such as polypropylene particulate material or powdered material; for example, Eltex HY-P or Eltex RP-P products (obtained from Solvay Chemical Co.). The polypropylene used whether an aqueous emulsion form or solid powder form, in either event, is dispersed in the composition. As will be seen from certain examples given herein, the molecular weight of the polypropylene is sometime specified with the letter "D" being used. This stands for Dalton technique or methodology of describing or delineating the molecular weight. By the term polypropylene as used herein it is meant to include polypropylene homopolymers, polypropylene block-propylene-ethylene co-polymers, polypropylene random propylene-ethylene co-polymers, and polypropylene block or random propylene-other unsaturated hydrocarbon monomer co-polymers. Normally the polypropylene used is the homopolymer form, however if a copolymer form thereof is used then preferably at least about 60% of the copolymer is polypropylene, with more preferred results being obtained at an 80% level for the polypropylene and best results being at 90% or higher.
The polypropylene in the composition should generally be present within the range of approximately 1% to 40% by weight of the composition; with preferred results being obtained when the polypropylene is present within the range of about 2% to about 30% by weight of the composition; and with best results being obtained when the polypropylene is present within the range of about 4% to about 15% by weight of the composition.
As referred to, polypropylene or polypropylene emulsions used herein contain appropriate emulsifying agents or suspending agents. Particularly useful for this purpose are non-ionic surfactants (e.g., ethoxylated alcohols), anionic surfactants, cationic surfactants, and amphoteric surfactants. Preferred materials for this purpose are as follows.

Non-ionic Surfactants:

Ethoxylated Alcohols
Ethoxylated Alkyl Phenols
Ethoxylated Fatty Acids
Fatty Esters
Glycerol Esters and Derivatives
Sorbitan Derivatives
Glycol Esters and Polyethylene Glycols

Anionic Surfactants:

Alkyl Aryl Sulphonates
Alkyl Ether Sulphates
Alkyl Sulphates
Carboxylic and Polycarboxylic Derivatives
Detergents Intermediates
Olefin Sulphonates
Sulphates and Sulphonates of Ethoxylated Alkyl Phenol
Sulphates and Sulphonates of Oils, Amines, Amides and Fatty Esters

Cationic and Amphoteric Surfactants:

Amines Ethoxylates
Imidazolines
Quaternary Salts
Tertiary Amines
Typical emulsifying agents or wetting and dispersing agents are: the ethoxylated alcohols, such as: Genapol X-060 and Genapol X-080 (available from Hoechst Chemicals); also usable are the Nonyl Phenol alcohols, such as, Antarox CO-530 and Antarox CO-630 (available from Rhone-Poulenc Chemicals Co.) [available in the U.S.A. as Igepal CO-530 or CO-630]; and ethoxylated castor oil, such as Emulan-EL (available from BASF).
The thickening agent used in the composition should generally be present within the range of 0% up to 5% by weight of the composition; with preferred results being obtained when it is present within the range of about 0.05% to about 5% by weight; and best results being obtained when it is present within the range of about 0.01% to about 3% by weight of the composition. These thickening agents, or suspending agents as they are sometimes referred to, may be: organo modified clays, soluble organic polymers, soluble thixotropic polymers; with specific thickening agents being materials such as, hydroxyethylcellulose or, sodium carboxymethyl cellulose.
The preservative agent used in the composition should generally be present within the range of about 0% to about 3% by weight of the composition; with preferred results being obtained when it is present within the range of about 0.01% to about 3% by weight; and with best results being obtained when it is present within the range of about 0.1% to about 2% by weight of the composition. Typical preservative agents that may be used are: hexahydrotriazine, Acticide BX (Thor Chemicals Co., U.K.) which can be described as a synergistic blend of aromatic compounds, that is, a blend of isothiazilone and chloroacetamide with n-formal; or Emulcid (available from Thor Chemicals), or Grotan BK (available from Sterling Industrial company), with both of these latter materials being Hexahydro-1, 3, 5 Tris (2 hydroxy ethyl) - s - triazine.
Other additives may also be used in the composition of this invention, such as graphite powder, boron nitride, polytetrafluoroethylene, talcum powder, naphthalene sulphonate, diammonium phosphate, sodium silicate, depolymerized rubber, dextrin, terephthalic acid, zinc stearate, and molybdenum disulfide. When these other additives are used they should generally be present within the range of about 0% to about 45% by weight of the composition; with preferred results being obtained when these other additives are present within the range of about 0.01% to about 40% by weight; with best results being obtained when these other additives are present within the range of about 0.2% to about 30% by weight of the composition.
The pH control agent for use in the invention should be a soluble alkaline agent such as ammonium hydroxide; however, other caustic materials may be used such as sodium hydroxide or the like. The pH control agent is not necessary in non-aqueous formulations of the invention; and even with respect to certain aqueous formulations (e.g., Example No. 6, which is acidic in nature) it may not be necessary to use a pH control agent. Broadly stated, the soluble alkaline agent may be present within the range of about 0.05% to about 10% by weight of the composition; with preferred results being obtained if it is present within the range of about 0.1% to about 6% by weight; and with best results being obtained if it is present within the range of about 0.2% to about 3% by weight of the composition. As referred to above this agent should preferably control the pH of the composition such that it is within the range of approximately 8 to 11; with preferred results being obtained when the pH is controlled such that it falls within the range of about 8.5 to 10.
In order to further illustrate the invention, the following examples are provided. It is to be understood, however, that the examples are included for illustrative purposes and are not intended to be limiting of the scope of the invention as set forth in the subjoined claims.

Examples of Forging Lubricant Compositions Hot and Warm Forging Lubricants

Example 1:	Emulsified Polypropylene Solids	8.4%
	(From An Aqueous Emulsion Such As Emrel 7) Avg. M.W. 4500D Hickson & Welch Ltd.
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.8%
	Terephthalic Acid	3.0%
	Dextrin	2.8%
	Sodium Hydroxide	1.4%
	Hydroxyethyl Cellulose	0.4%
	Preservative (e.g. Acticide BX)	0.1%
	Water	83.1%
		$\bar{100.0%}$

Example 2:	Emulsified Polypropylene Solids	2.0%
	(From An Aqueous Emulsion Such As Emrel 7) Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.2%
	Graphite Powder	2.0%
	Sodium Carboxymethyl Cellulose	0.15%
	Sodium Hydroxide	0.10%
	Dextrin	0.3%
	Preservative (e.g. Acticide BX)	0.1%
	Water	95.15%
		$\bar{100.0%}$

Example 3:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	3.3%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.3%
	Graphite Powder	2.0%
	Sodium Carboxymethyl Cellulose	0.15%
	Sodium Hydroxide	0.10%
	Dextrin	0.3%
	Preservative (e.g. Acticide BX)	0.1%
	Water	93.75%
		$\bar{100.0%}$

Example 4:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	8.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.8%
	Graphite Powder	8.0%
	Sodium Carboxymethyl Cellulose	0.6%
	Sodium Hydroxide	0.3%
	Dextrin	1.3%
	Preservative (e.g. Acticide BX)	0.2%
	Water	80.8%
		$\bar{100.0%}$

Example 5:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	8.6%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.9%
	Graphite Powder	8.6%
	Sodium Carboxymethyl Cellulose	0.7%
	Sodium Hydroxide	.
	Dextrin	1.5%
	Sodium Silicate Solution (42% Solids)	3.8%
	Preservative (e.g. Acticide BX)	0.5%
	Water	75.4%
		$\bar{100.0%}$

Example 6:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	5.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.5%
	Graphite Powder	19.5%
	Naphthalene Sulphonate	5.0%
	Diammonium Phosphate	10.0%
	Water	60.0%
		$\bar{100.0%}$

Example 7:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	5.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	0.5%
	Graphite Powder	17.3%
	Naphthalene Sulphonate	2.6%
	Sodium Carboxymethyl Cellulose	1.3%
	Sodium Silicate Solution	5.3%
	Ammonium Hydroxide 25% Solution	0.4%
	Preservative, Hexahydrotriazine	0.2%
	Water	67.4%
		$\bar{100.0%}$

Example 8:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	36.4%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	3.6%
	Water	60.0%
		$\bar{100.0%}$

Example 9:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	10.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	1.0%
	Talcuum Powder	8.0%
	Sodium Naphthalene Sulphonate	1.0%
	Sodium Carboxymethyl Cellulose	1.0%
	Preservative (e.g. Acticide BX)	0.4%
	Water	78.6%
		$\bar{100.0%}$

Example 10:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	10.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	1.0%
	Boron Nitride Powder	2.0%
	Sodium Naphthalene Sulphonate	1.0%
	Sodium Carboxymethyl Cellulose	1.0%
	Preservative (e.g. Acticide BX)	0.4%
	Water	84.6%
		$\bar{100.0%}$

Example 11:	Finely Divided Polypropylene Powder (derived from Eltex HY-P)	10.0%
	Graphite Powder	10.0%
	Sodium Carboxymethyl Cellulose	2.0%
	Preservative (e.g. Acticide BX)	0.4%
	Water	77.6%
		$\bar{100.0%}$

Example 12:	Finely Divided Polypropylene Powder (derived from Eltex RP-P)	10.0%
	Mineral Oil (e.g. BP 1201 Solvent Neutral)	70.0%
	Graphite Powder	10.0%
	Depolymerized Rubber	2.0%
	Zinc Stearate	8.0%
		$\bar{100.0%}$

Cold forming lubricants designed to lubricate under cold forming conditions are shown below, and could be utilized under other conditions.

Example 13:	Emulsified Polypropylene Solids (From An Aqueous Emulsion Such As Emrel 7)	10.0%
	Non-ionic Emulsifiers, (Ethoxylated Alcohol Types)	1.0%
	Molybdenum Disulfide Powder	12.5%
	Sodium Carboxymethyl Cellulose	1.3%
	Preservative (e.g. Acticide BX)	0.4%
	Water	74.8%
		$\bar{100.0%}$

Example 14:	Finely Divided Polypropylene Powder (derived from Eltex HY-P)	10.0%
	Acrylic Resin (e.g. Paraloid B48N)	5.0%
	Trichloroethylene	80.0%
	Methyl Ethyl Ketone	5.0%
	Dyestuff (e.g. Waxoline Green PC)	Trace
		$\bar{100.0%}$

Example 15:	Finely Divided Polypropylene Powder	2.0%
	Acrylic Resin Aqueous Emulsion (e.g. Glascol 616E from Allied Colloids Co.)	17.0%
	Isopropyl Alcohol	80.0%
	Ammonium Hydroxide 25% Solution	1.0%
	Dyestuff (e.g. Waxoline Blue A)	Trace
		$\bar{100.0%}$

While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to fulfill the objects, benefits, and/or advantages of the invention, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

Claims

A water based forging lubricant composition, comprising in weight percent:
(a) about 1% to about 40% polypropylene having an average molecular weight between about 500 and about 300,000,

(b) zero to about 8% of emulsifying agent to assist in maintaining materials of the composition in an emulsified form,

(c) zero to about 5% of thickening agent to assist in maintaining the composition at a suitable viscosity,

(d) zero to about 3% of a preservative agent,

(e) zero to about 45% of an additive selected from at least one material of the group consisting of graphite powder, boron nitride, polytetrafluoroethylene, talcum powder, naphthalene sulfonate, diammonium phosphate, sodium silicate, depolymerized rubber, dextrin, terephthalic acid, zinc stearate, and molybdenum disulfide,

(f) about 0.05% to about 10% of a soluble alkaline agent to maintain the pH of the composition within the range of about 8 to about 11,
and the balance water.
The composition of claim 1 wherein said polypropylene is in finely divided dispersed form.
The composition of claim 1 or 2 wherein component (b) is present from about 0.01% to about 8%.
The composition of any one of claims 1 to 3 wherein component (c) is present from about 0.05% to about 5%.
The composition of any one of claims 1 to 4 wherein component (d) is present from about 0.01% to about 3%.
The composition of any one of claims 1 to 5 wherein component (e) is present from about 0.1% to about 40%.
The composition of any one of claims 1 to 6 wherein component (f) is present from about 0.1% to about 6%.
The composition of claim 1 or 2 wherein
component (a) is present from about 2% to about 30%,
component (b) is a non-ionic emulsifying agent present from about 0.01% to about 8%.
component (c) is present from about 0.05% to about 5%,
component (d) is present from about 0.01% to about 3%,
component (e) is present from about 0.1% to about 40%,
component (f) is present from about 0.1% to about 6%.
The composition of claim 8 wherein
component (a) is present from about 3% to about 15%,
component (b) is a non-ionic emulsifying agent present from about 0.1% to about 5%,
component (c) is present from about 0.1% to about 3%,
component (d) is present from about 0.1% to about 2%,
component (e) is present from about 0.2% to about 30%,
component (f) is present from about 0.2% to about 3%.
A process of forging a metal part using the lubricant composition of any one of claims 1 to 9.
A forging lubricant composition, comprising in weight percent:
(a) about 1% to about 30% dispersed polypropylene having an average molecular weight between about 500 and about 300,000,

(b) zero to about 8% of emulsifying agent to assist in maintaining materials of the composition in an emulsified form,

(c) about 50% to about 92% liquid carrier for the composition,

(d) about 0.1% to about 40% of an additive selected from at least one material of the group consisting of molybdenum disulfide, graphite, boron nitride, zinc stearate, a resin binder, and a pH control agent.
The composition of claim 11 wherein component (b) is present from about 0.01% to about 8%.
The process of forging a metal part using the lubricant composition of claim 11 or 12.