JPH06212181A - Carrier-free metal working lubricant, its preparation and method of using it - Google Patents

Abstract

PURPOSE: To obtain a carrier-free pulverulent metalworking lubricant composition comprising at least two particulate lubricant components producing less smoke and oily dirt, and to provide a method for producing the composition.

CONSTITUTION: This invention relates to a pulverulent metalworking lubricant composition. In one preferred form, this composition contains at least two lubricant components, one of which comprises a resin having a highly polar functional group, and the composition is formed by a method comprising the steps of: (a) forming a dry mixture of the particulate lubricant components, and (b) agglomerating the admixture to form agglomerated particles.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates generally to the field of metalworking lubricants, and in one particular aspect to forging lubricants. More specifically, in one aspect, it relates to a forging lubricant composition and a method of using the composition for thermal forging of metal working.
Metal parts of various shapes and sizes are manufactured by various types of forging operations, and these parts are formed from a large number of metals and metal alloys. So many parts are, for example, steel, to name a few,
Forged from metals and metal alloys such as aluminum, titanium, and high nickel alloys.

[0002] The conditions under which a metal part is forged, of course, vary widely depending not only on the characteristics of the metal but also on the complexity of the size and shape of the designed part. Small, thin, and easily shaped parts are clearly less rigorous than relatively flowable metals such as aluminum, as compared to what it takes to forge large, more complex shaped parts from metals such as steel. It could be forged under other conditions.

[0003]

BACKGROUND OF THE INVENTION This application is a continuation-in-part application of application number 07 / 664,104, filed March 4, 1991, the latter of which was filed on June 16, 1989. It is a partial continuation application of No. 07 / 367,311.

Each forging condition requires a special lubricant for each, and there are now many water-based, oil-based and organic solvent-based lubricants for use in various forging operations. Due to the nature of many lubricant systems, especially those used under the most demanding forging conditions, the safety, occupational health, and environmental hazards associated with use should be avoided as much as possible while maintaining the required function. Requires a compromise to the user in order for the property to work. Moreover, in some cases, more stringent health and environmental guidelines are now being enforced, which may make the use of certain lubricant systems very expensive or even difficult to use at all. It is at this point and related problems that the present invention is directed.

In standard high die forging operations, such as those suitable for making large and complex parts from aluminum alloy raw materials, effective lubricants include carriers containing common mineral oils and / or volatile organic solvents. Various lubricants are contained therein. The die used in the forging operation should be between 350 ° F and 82 ° F to ensure proper metal flow during the forging operation.
It is kept at a high temperature in the range of 5 ° F.

Forging lubricants are commonly used by spraying dies and workpieces, and because of their temperature, mineral oils and volatile organic compounds burn up quickly, and relatively small amounts of residue that actually act as lubricants. Leave. As anyone who has observed forging operations is well aware, the ignition of mineral oils and volatile organic compounds creates a fairly large flame, and the spray wand spraying the lubricant appears to be firing. In addition, in general, when mineral oil and volatile organic compounds burn up, a large amount of smoke is generated because at the same time a significant portion of the lubricant burns. Because of this situation, it is well known that attempts to improve the performance of forging lubricants lead to re-formulation, which is accompanied by a significant amount of smoke generation.

Similar difficulties are inherent in the use of oil-based paste die lubricants. Although paste die lubricants contain little or no volatile organic compounds, their carrier oils burn partially or completely at normal forging temperatures, producing a significant amount of smoke.

The hazards, costs and environmental problems associated with such forging operations are large and rapidly becoming greater. In states like California, where environmental protection laws and regulations design strict standards for industrial activity, and in other states with similar environmental protection plans,
Smoke generated by large-scale forging operations poses a serious problem.

Since the Environment Agency often monitors smoke emissions by atmospheric surveys, it takes great care to reduce the smoke generated from forging operations. Unfortunately,
This sometimes limits efforts to emit smoke from the building containing the forging operation. This results in air pollution inside the building.

The important economic issues to consider are:
For example, California imposes a tax on each gallon of volatile organic compounds released into the atmosphere. More importantly, as air quality standards continue to rise, it will soon be foreseeable that forging operations will strictly prohibit the emission of large amounts of smoke.
You will then be forced to find an alternative lubricant that emits very little smoke or to stop working altogether.

A similar problem exists with the use of oil-based or solvent-based lubricants in small-scale forging or other metalworking operations, because the extra lubricant material in this die is an environmental hazard. It is thought that there is. Therefore, the disposal will be tightly controlled and costly.

Another related concern is the strong need for alternative metalworking lubricants. As mentioned above, a flame is generated when plain mineral oil and a volatile organic compound-based lubricant are applied to a heated die. Therefore, effective fire protection and fire-fighting equipment such as fire extinguishers and sprinklers must be provided in the immediate vicinity of the forging operation. In fact, the digestive system is regularly used in many forging operations and the cost of maintaining it is substantial. In general, all types of fire prevention, firefighting equipment and fire detection systems are legitimate and substantial investments in thermal forging operations and are a maintenance cost item.

A problem associated with conventional volatile organic compound-based lubricants is the need for special equipment due to their high flammability. This also imposes considerable costs with normal lubricant usage.

The fact that these flammable lubricants have to be transported in special containers and special vehicles is also a source of extra expense, risk and inconvenience in their use.

Yet another disadvantage caused by the flaming of oil and solvent carriers is that the smoke produced tars on the machine, finished parts, floors, windows and almost everything else in the same building as the forging equipment. To deposit deposits. Apart from the aesthetic inconvenience of such deposits, there are also economic and health concerns. Many large forging facilities must maintain a permanent steam cleaning facility at a significant cost.

Various types of dry lubricants and methods of applying them to metal surfaces have been proposed for use in a wide range of environments, either because of the lubricant itself or because of the use thereof. None have been widely applied due to their inherent drawbacks.

For example, in titanium forging work, it has been proposed to use a powder lubricant consisting of glass and a ceramic component by shooting a steel material if necessary and embedding the lubricant in the forging tool surface by high pressure spraying. ing. The method is described as sandblasting a lubricant onto the workpiece surface and is intended for cold work and the effect of smoothing the workpiece surface. Of course, such a high pressure spray method requires the use of fairly expensive spray equipment and there is also the risk of injury to workers if misdirected.

It has also been proposed to spray the dried reactants onto a hot metal surface to form a reaction product at that location. Furthermore, combinations of various dry lubricants have also been proposed for use in a wide range of applications. But,
Many of these lubricating compositions are similarly defective.

After forging, whether normal lubricants or dry lubricants, aluminum parts are subjected to corrosive etching to remove lubricant residues. Corrosive etching may be used in combination with pickling in a preferred manner well known in the art. In many aluminum forging operations, pickling favors corrosive etching.

As is well known in the art, these cleaning and etching methods are quite handy. Generally, corrosive etching baths contain 5 to 15 hydroxides of alkali metals in water.
It is the one that is dissolved by weight. Common acid baths are similarly strong, often containing high concentrations of nitric acid. In forging operations using conventional solvent or oil based lubricants, cleaning and etching methods work well to remove substantially all lubricant residues from the forged parts.

However, despite the harsh cleaning and etching conditions, even after the cleaning has been left unetched and the part is subjected to physical removal methods such as brushing or polishing, the powder lubricant residue still remains. It is known that it adheres strongly to parts.

It has also been found that when using a multi-component powder lubricant, it is difficult to obtain a solid spray pattern by using an ordinary powder coating device. Overspray, underspray, puffing, and spattering can also have significant drawbacks both in terms of providing a functional lubricant coating on the workpiece and in effectively using the powdered lubricant material. all right. Overall, the spray method has hitherto been far too far off for commercial acceptance. It has also been found that spraying using a fluidized tank, as is commonly used as a powder spray tank, is completely unthinkable when using powder coating equipment. Even the use of powder coating equipment with self-feeding tanks has generally not been a significant improvement in robustness.

Although the particular problems encountered in aluminum forging operations have been detailed, many of the same and related other problems exist in other metal working environments. This includes not only hot forging operations such as the production of steel and titanium parts by forging, but also various other metal working and metal forming operations. Examples include extrusion, drawing, die removal and other hot and cold forming operations, many of which use lubricants in aqueous or solvent based carriers.
Technical and economic advantages could be realized by applying the improved dry lubricating composition to such operations.

[0024]

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a forging lubricant and method of use thereof that significantly reduces the amount of smoke and greasy dirt produced during forging operations. . The related objective is to remove the organic carrier, which is an essential part of conventional high performance forging lubricants.

Thus, a general object of the present invention is to provide a lubricant which eliminates many of the health, environmental and safety drawbacks of conventional lubricants having mineral oil as a carrier and volatile organic compounds. It is to be.

Yet another object is to eliminate the need for specific shipping and storage facilities needed with conventional lubricants. A further important object of the present invention is to provide a powder lubricating composition that can be applied to a workpiece and / or die for providing a substantially uniform coating using conventional powder coating equipment.

A related object is to provide a method of making a powder lubricant composition that can be applied to a work piece and / or die for providing a substantially uniform coating using conventional powder coating equipment.

Yet another important objective is to provide a high performance dry lubricant that does not form residues that cannot be removed by conventional cleaning methods. Other objects and advantages of the invention will be apparent to those skilled in the art from the following description and claims of the invention.

[0029]

[Means for solving the problems] As the most basic form,
The compositions of the present invention are carrier-free powder metalworking lubricants, i.e., oils and volatile organic compound-free lubricants commonly used as carriers for lubricating compositions for forging. Similarly, in one form, the method of the present invention is a method of forming a workpiece in a metal forming machine, wherein the carrier-free powder lubricant composition is in an amount effective for at least one metal forming machine and the work piece. Coating and forming the workpiece in the machine.

The carrier-free powder lubricating composition of the present invention generally has lubricating properties at temperatures commonly employed in forging processes and is a physical material that can be applied to dies or workpieces by conventional powder coating equipment. It may include any substance that can be in the form.

According to the invention, the need for incorporating mineral oil and / or volatile organic compound-based carriers is completely eliminated, so that the smoke produced by conventional lubricants is significantly reduced.

In one form, the present invention is a carrier-free powder metal having a highly polar functional group, capable of dissolving under strongly acidic or basic conditions, and containing at least one resin which is solid at room temperature. It is a work lubricating composition.

In another aspect, the present invention is a carrier-free powder metal working lubricant composition having a substantially uniform particle size. Yet another aspect of the present invention is a method of making a carrier-free powder metalworking lubricating composition comprising the steps of forming a dry mixture of lubricant components, the mixture being heated to a temperature at which at least one component of the mixture melts. Heating, stirring the heated mixture to form a substantially uniform melt, cooling the substantially uniform melt to form a substantially solidified mass, and substantially The step of crushing the solidified mass into the required particle size is included. In another aspect, the invention is a method of forming a homogeneous melt of a lubricant component and spray drying the melt to the required particle size.

In yet another aspect of omitting the melting step, the present invention comprises the steps of forming a dry mixture of the specified components, and agitating the mixture to form agglomerated particles of carrier-free powder metal working lubricant. It is intended for a method of forming a carrier-free powder metal working lubricant. Preferably, the method further comprises adding an adhesive to allow the particles to adhere to each other. More preferably the adhesive is an aqueous solution; most preferably the adhesive is an aqueous solution containing a thickener and / or a surfactant.

Yet another aspect of the present invention is a carrier-free powder metalworking lubricating composition having at least one resin which has a highly polar functional group, is soluble under strong acidic or basic conditions and is solid at room temperature. Of a work piece in a die, the method comprising the steps of applying an effective amount of at least one of the die and the work piece and forging the work piece in the die.

There are many advantages inherent in the compositions and methods of the present invention. In particular, it will be possible to remove much of the smoke that has been generated by burning mineral oil and volatile organic compound carriers up to now, and to continue the forging work as a business while fully complying with environmental laws and regulations. Became possible. Furthermore, the project can be continued without the financial burden of paying taxes due to the release of volatile organic compounds. In many cases, the compositions and methods of the present invention allow forging operations to continue under tightly regulated environmental guidelines that would otherwise be completely closed.

Other economic advantages of the present invention are of great importance as well. The reduction in weight and volume achieved by eliminating conventional lubricant carriers has resulted in savings in shipping and storage costs. Furthermore,
The carrier-free composition of the present invention is neither flammable nor dangerous and can be shipped and stored like any other non-hazardous material, resulting in savings in transportation and storage costs. . Further, instead of the conventional 55 gallon steel drums of lubricant, the 5 gallon plastic cans of the carrier-free powder metal working lubricant of the present invention are sufficient, thus significantly reducing packaging costs.

In the forging operation itself, the compositions and methods of the present invention allow for significant reductions in the installation and maintenance costs of fire prevention and firefighting systems, generally much less costly and much safer for people. It becomes possible to maintain a good environment.

By using the compositions and methods of the present invention, further savings can be realized in terms of fire, worker compensation, and liability insurance coverage. In conventional lubricants, the cost of raw materials can be significantly reduced by removing the carrier material, which makes up more than 80% of the composition on a weight and volume basis.

By using the compositions and methods of the present invention, there is a significant reduction in the dregs produced due to the absence of mineral oil and volatile organic compound carrier burnout, which is a costly addition to plant and finished parts. The need to maintain space-consuming cleaning equipment can also be reduced.

In addition, functional advantages are also achieved by the present invention. The addition of a resin that dissolves in an alkaline and / or acid bath can provide the benefits of a cleanable forged part even when using a dry powder lubricant.

Furthermore, by maintaining the particle size of the lubricant powder in a narrow range, even when applying a conventional powder coating apparatus and using a fluidized tank as a powder storage tank,
The lubricant particles can be applied uniformly. And, by controlling the lubricant powder particle size by a novel manufacturing method, not only is the reliability of the spray provided, but the properties and cleaning properties of the lubricant are improved.

As mentioned above, the composition of the present invention, in its most basic form, is a carrier-free powder metal working lubricant. It generally has any lubricating properties at the temperatures applied in the metal forming process and includes any substance that can be brought into a physical form that can be applied to dies and / or workpieces by conventional powder coating equipment. You may stay.

Many materials are known that can impart a lubricating function to the die and physically separate the die from the work piece, and many of these materials are the physical ones required to carry out the present invention. It is in the form of; that is, it is a solid at room temperature.
The materials used in the compositions of the present invention are typically at the temperatures normally used during forging operations, for example about 600 for aluminum.
° F to 1000 ° F, about 1500 for steel or titanium
It does not have to remain solid or powder from -20 ° F to 2500 ° F. It is sufficient that they are present in a particular form at the temperature of use. Partially or completely melts or burns when it comes into contact with a heated die or workpiece, but in certain configurations it can be subjected to conventional powder coating equipment. In fact, when at least one component of a carrier-free powder metalworking lubricant becomes tacky when heated, it can help the dry metalworking lubricating composition to adhere to the surface of the workpiece and die. preferable.

It is contemplated that any conventional die material capable of maintaining a physical barrier between the die and the workpiece and functioning as a solid lubricant can be used in the compositions of the present invention. This is just one example, and it ’s a metal soap,
Included are fatty acids, graphite, ceramics, high melting polymer resins, natural and synthetic waxes, gilsonites, glasses, and mixtures thereof.

Useful metal soaps are solid at room temperature and include many sulfonates, naphthenates, and carboxylates. Of course, aliphatic metal soaps such as zinc stearate and sodium stearate are preferred in view of their known properties, ease of use and low cost. However, other metal soaps known for their lubricant properties,
For example, by way of example, metal soaps including salts of the fatty acids tin, copper, titanium, lithium, calcium, and other alkali and alkaline earth soaps are included as useful.

Fatty acids themselves which are solid at room temperature may also be included and are attractive for such use due to their relatively low cost, ease of use and their property of imparting lubricity to the overall composition. . An example is stearic acid, which is convenient to use because it has good lubricating properties, is non-toxic, inexpensive and easy to use.

Certain ceramic materials, such as graphite and boron nitride, are useful because they maintain physical separation performance between the die and the workpiece. The exact mechanism of physical separation is unknown, but it is believed that this property is due to the relatively planar crystal structure of these materials.

Poly (tetrafluoroethylene) (PTF) is just one example of useful high melting point polymeric resins.
E), high density polyethylene (HDPE), poly (vinyl chloride) (PVC), polyesters, polyethylene glycols, polyacrylates, polymethacrylates, and polyamides. In fact, almost any thermoplastic is used.

The thermoplastics of the present invention act as a plastic matrix on the heated metal surface where the individual lubricant components can be retained during metal forming. As is well known,
Thermosetting resins, such as phenolic resole resins, generally lose their fluidity when heated. The ability of thermoplastics to remain plastic throughout the metal forming process is believed to be an important property of the polymeric resin component of the lubricants of the present invention.

Among the natural and synthetic waxes used as useful, the relatively high molecular weight polyethylene wax is generally preferred due to the lubricity it imparts.

The glass materials used in the present invention are preferably low melting glasses and include alumina, alumina / silica, silica, and borax. These glass materials may optionally be used in the form of chopped fibers.

As one basic form of the method of the present invention, at least one of the die and the workpiece is coated with an effective amount of a carrier-free powder lubricant composition and then formed into a finished part that requires the workpiece. To die. Generally, application of the lubricant according to the invention is carried out using conventional powder coating equipment.

As an alternative to that within the scope of the present invention, carrier-free powder metal machining lubricants have little lubricant loss due to electrostatic attraction of particles to the die and / or workpiece. And, because electrostatic coating is known to be applied uniformly on even complex shaped parts, it is applied to electrostatic coating equipment.

In high temperature environments such as aluminum, steel, and titanium forging operations, it is quite difficult to maintain a sufficient charge on the lubricant particles when the powder spray is directed at the die or workpiece near the press. Yes, electrostatic powder coating equipment offers little advantage over non-electrostatic equipment. However, electrostatic devices have considerable utility at any temperature for prepainted aluminum, steel or titanium workpieces, after which the workpieces are heated in a dryer prior to entering the press. Similarly, cold forming, such as stamping, which takes place at much lower temperatures, retains the advantages of electrostatic coating.

The lubricants of the present invention may be applied to the heated or heating die in the same manner as conventional lubricants are applied. Alternatively, the lubricating composition may be sprayed onto an unforged cold work piece, which is then heated to partially melt the composition and placed in a heated die to forge it. . In cold forming operations, the workpiece may be spray painted and the conventional step of heating the workpiece to burn or vaporize the aqueous solvent or oil carrier may be omitted.

Due to their very dusty nature, which is even dust-like, materials such as graphite and amorphous boron nitride, if not charged electrostatically, are some of the other listed above. Does not stay on the surface of the die and workpiece as easily as the compound. Thus, undesirably, draft air or air flow causes powder forging lubricant to be lost from the die and / or workpiece prior to performing the forging operation. Therefore, if one or more of these materials is included in the lubricant of the present invention formed as a dry mixture to be carried to a powder coating machine operated without charge, the lubricant will be retained on the die and the work piece. Therefore, it is also preferable to include at least one or more components having adhesiveness at a general forging temperature, such as glass, gilsonite, or high melting polymer resin. Some examples of the lubricating composition and metalworking method of the present invention are described below.

[0058]

Examples 1 and 2 The following compositions were used to forge box channels with thick walls of about 0.125 inches in a lap die made of aluminum alloy stock. The press was hydraulic, the workpiece temperature was 700 ° F and the die temperature was 375 ° F:

Example 1

Example 2

Only 7 parts were forged; spray technology could not be optimized. However, the forged parts were tested and found to have excellent metal deformation and the die groove walls were well filled. Excellent downsizing was found in the dimensions of the critical areas and the parts could be easily removed from the die without sticking at all. Die comrades tended to stick together a bit; but this is usually the case with parts of this shape. The extent of smoke generation was significantly less than with conventional solvents, oils and graphite lubricants. Based on this rather limited trial, both were effective as forging lubricants, but the composition of Example 1 outperformed the composition of Example 2 in each aspect observed.

Example 3 For comparison, the composition of Example 1 was evaluated using a conventional solvent based zinc stearate forging lubricant as a standard. The press was a mechanical pressure type with a workpiece temperature of 700 ° F and a die temperature of 400 ° F.

Forty parts were each forged for each composition. As a result of testing the forged parts, excellent metal deformation was observed without any catch (drag). An excellent downsize was seen in the size of the important part. The part could be easily peeled off the die without sticking at all, and there was no lubricant residue on the part. The extent of smoke generation using the composition of Example 1 was significantly less than that generated during the trials reported in Examples 1 and 2.

Examples 4 and 5 The following compositions were evaluated under the same conditions as in Example 3. Each exhibited satisfactory performance and produced significantly less smoke than conventional solvent-based lubricants.

Example 4

Example 5

The composition of Example 5 was also evaluated by forging steel and titanium in a high temperature environment and found to have satisfactory performance with either metal forging.

Examples 6-8 The following carrier-free powder lubricant compositions were also found to be useful for forging aluminum and aluminum alloy workpieces:

Example 6

Example 7

Example 8

Example 9

Examples 10-15 It was found that other carrier-free powder lubricant compositions can be used for high temperature forging of titanium and steel. Its composition is as follows:

Example 10

Example 11

Example 12

Example 13

Example 14-1

Example 14-2

In special applications, forging of steel engine valves, many advantages have been found by using lubricants of the following composition:

Example 15

In this particular application, the composition of Example 15 outperformed the composition of Example 5 in many respects.
In particular, the metal flow was better, so cracks were eliminated, the shape of the part could be improved, and the die life was improved. The exact mechanism that produces these improved results is unknown, but the sulfur particles melt at the surface of the die and workpiece,
It is believed that the molten sulfur further enhances lubricity and greatly enhances the pressure characteristics of the dry lubricating composition. In addition, sulfur can promote the formation of carbon sulfide and other lubricious residues that act as a die release agent to ensure a clean separation between the forged part and the die.

Addition of about 2 to about 30% by weight of sulfur in the composition produces the above benefits, but for functional and economic reasons about 5 to about 20% by weight is preferred. Since gilsonite tends to promote the formation of tar-like residues on forged parts, reducing or removing it from the composition can improve the cleanability of aluminum and aluminum alloy parts to some extent. However, since Gilsonite has excellent lubricity, removing this component only slightly improves the cleanability and sacrifices performance, while Gilsonite is a dry mix due to its stickiness at forging temperatures. Helps the lubricant being made adhere to the work piece and die.

However, in addition to a level of cleanability comparable to conventional solvent-based and / or oil-based forging lubricants, the same required functional properties due to Gilsonite and other similar tacky materials are unexpectedly expected. It has been discovered that a component that can replace Gilsonite and that can be exerted is extremely effective.

In particular, by using a resin component having certain physical and chemical properties, it is possible to combine the excellent function with the extremely excellent cleaning property required for commercial use. .

In general, resins having excellent lubricating properties at forging temperatures are solid at the temperature of use and have high polar functional groups so that they can be dissolved in corrosive etches and / or acid baths, as described above. It will have both properties. In general, halogenated resins produce dangerous combustion products and are preferably avoided in hot forging operations.

Specific resins that can be used in the practice of the present invention include polyethylene glycol resins, polyester resins having hydroxyl or carboxyl functional groups at the terminals, polyacrylic acid ester resins, polymethacrylic acid ester resins, and polyamide resins, and There are mixtures of these.

Further, the thermoplastic resin plastics of the present invention are
It facilitates the removal of lubricant from the die after the forming die. As is well known, a thermoplastic resin having a bond of oxygen atoms in a polymer skeleton has an active site against an attack of an acid or a base, which allows the resin to be easily disintegrated and solubilized. Generally, the resin tends to attach other components to the work piece, so that the long chain polymer is decomposed during the cleaning of the work piece after the die is formed in an acid or basic solvent, so that other lubricants are not formed. It also helps remove ingredients.

Currently, polyester and polyethylene glycol resins are preferred because of their excellent lubricating performance, excellent cleaning properties and lack of inconvenient burning properties. Examples of these resins are polyethylene glycol resins such as E4000 and E8000 sold by BASF under the registered trademark "Pluracol", Cargill.
There are polyester resins having a hydroxyl group such as 30-3016 sold by the company and carboxyl group polyester resins such as 30-3065 sold by Cargill. These materials are generally dry solids at room and use temperatures and therefore can be applied to workpieces and dies by conventional powder coating equipment.

These resins are used when they are used in the carrier-free powder lubricant compositions of the invention in an amount of from about 5 to about 50% by weight, preferably from about 10 to about 30% by weight in the plastic. It provides properties that combine lubricity and cleaning properties. While these resins are more expensive per unit weight than many of the other components, they have the preferred functional properties, but it is most preferred that the amount of resin be as low as possible. Generally, a high melting point resin having a highly polar functional group is
If the amount is at least 5% by weight, the improvement of the cleaning property can be observed, but the upper limit concentration is more limited from the economical aspect than the functional aspect.

A slight variation in the amount of resin used does not result in easily observable changes in functionality or cleanability (and in determining the optimum concentration of any other component of the composition). It is important to be careful.
In fact, performance and cleanability ratings are highly subjective, and neither quantitatively sensitive to meaning. Therefore, the weight percentage of resin or any other component in the lubricating composition is not narrow and critical in the practice of the invention, and significant variations do not adversely affect performance.

Example 16 A lubricating powder composition was formulated according to the invention as follows:

The above compounded lubricants have been successfully utilized in high performance aluminum forging operations to forge many aircraft parts. Additionally, the lubricant of Example 16 was found to perform well in typical steel (engine valve) and titanium (turbine blade) forging operations.

Example 17 First Aluminum Part Using the Composition of Example 16
Was forged with a second group of forged aluminum parts using the composition of Example 5 and a series of three comparative cleaning tests was performed. The cleaning procedure and the results obtained are summarized below.

Cleaning Test Details Test A-Process (Standard Etch) Step 1-Caustic Soda, 8 oz / gal (oz / ga)
l), 175-180 ° F, 120 seconds. Step 2-Rinse, Cold Step 3-Rinse, Cold Step 4-Smut removal, 25% nitric acid, 60 seconds Smut 5-Rinse, Cold Step 6-Rinse, Cold Step 7-Rinse, Thermal Results: Lubricant of Example 5 Removal: Poor Cleaning Removal of Lubricant of Example 16: Just Acceptable Cleaning

Test B-Process Step 1-24% sulfuric acid, 6% nitric acid, 180 ° F, 10
Min Step 2-Rinse, Cold Step 3-Rinse, Cold Step 4-Caustic soda, 8 oz / gal, 175-180
° F, 120 seconds Step 5-Rinse, Cold Step 6-Rinse, Cold Step 7-Desmut, Nitric acid 25%, 60
Second Smut 8-Rinse, Cold Step 9-Rinse, Cold Step 10-Rinse, Thermal Results: Example 16 Lubricant Removal: Essentially Clean; Equivalent to cleaning liquid lubricant with standard etch process.

Test C-Process Step 1-Nitric acid 50%, 120 seconds Step 2-Rinse, Cold Step 3-Caustic soda, 8 oz / gal, 140 ° F, 3
0-180 seconds Smut 4-rinse, cold Step 5-Smut removal, nitric acid 50%, 120 seconds Step 6-rinse, cold Step 7-rinse, thermal Results: Lubricant removal of Example 16: essentially clean; Equivalent to cleaning the liquid lubricant with the same etch process.

Following many such comparative cleaning tests, a further advantage of the lubricant of Example 16 was discovered over conventional zinc-containing lubricants; that is, the amount of zinc present in the etch solution. 95% reduction. Reducing the metal content of industrial waste is of course a valuable environmental and economic benefit

Examples 18-21 Lubricating powder compositions were formulated according to the present invention:

Example 18

Example 19

Example 20

Example 21

Maintaining a narrow particle size range for the carrier-free powder lubricants of the present invention can greatly improve spray efficiency and consistency, allowing the powder lubricant to be applied to the workpiece substantially uniformly. It has been determined.
And in another aspect, the invention is directed to a carrier-free powder lubricating composition in which the particles are of substantially uniform size.

As used herein, "substantially uniform diameter"
The phrase means that there are few or no particles having a diameter that is 50% larger or 50% smaller than the average particle size, as measured by "diameter". Most preferably,
Relatively little or no lubricating powder having a particle size that is 10% larger or 10% smaller than the average particle size.

Satisfactory results have been obtained with substantially uniform diameter lubricant particles having an average particle size (ie diameter) in the range of 10 microns to 420 microns. But,
A particle size of 40 microns or greater is preferred. This lower diameter limit is chosen to minimize the extent of lubricant particles left in the air in the form of dust. The purpose of minimizing dusting is twofold: to provide an environmentally safer environment for workers and to reduce loss of lubricating material by increasing the efficiency and accuracy of powder spraying. The upper limit of particle size is essentially a function of the sprayer's ability and the ability of the particles to adhere to the surface of the workpiece in a substantially uniform coating. The commercially available powder coating equipment used here has a diameter of 5
Particles between 0 and 100 microns seemed to work best.

One way to control both the average particle size and the range of particle sizes is to utilize as the starting material a milling and / or sieving substantially uniform size lubricating component. The screened ingredients are easily added using conventional dry blending techniques such as ribbon blenders, tumbling blenders, V-blenders from Patterson-Kelly, Inc., East Stroudsburg, PA. Mixed. An obvious drawback of the dry mixing procedure is the time, effort and expense involved in purchasing each component or processing it to the desired size and size range. A second drawback is that in the dry mixing process itself, the particles are ground by a large number of small particles, again widening the particle size range. Difficulties also occur with lubricants produced in this way; separation of lubricant particles due to particle size and weight differences of the various components, unacceptable degree of dusting and poor flowability due to the presence of fines. Etc.

A second method of preparing a carrier-free powder lubricant composition having a substantially uniform diameter involves grinding the solidified molten layer of the lubricant composition with a hammer mill. In particular, it has been found that high performance powdered lubricants having particles of substantially uniform size are formed in the following manner. First, the lubricating component, which may be in any conventionally available crushed form regardless of particle size, such as powders, flakes, small pellets, etc., is added and mixed in the desired proportions for dry lubrication preliminary. A mixture is formed. The dry lubricated premix is then heated with stirring to form an essentially homogeneous melt. About 100 ℃ to about 200 ℃
Is usually sufficient to obtain a melt-mixing consistency. The homogeneous melt is then cooled to form a solid mass. The solid mass is crushed at low temperature to the desired particle size by cold crushing technique. Devices capable of performing this operation are commercially available. In one such process, the homogeneous lubricating melt is loaded onto a rotating metal plate that has been cooled to about 40 ° F (10 ° C) and solidified into a sheet-shaped mass. The sheet is then broken into pieces in the width range of 1 to 3 centimeters. The debris is then milled in an air conditioned room with a hammer mill to the desired particle size. Other similar processes solidify the melt into a ribbon form which is then broken into chips and ground under appropriate conditions to the desired particle size. Grinding the melt phase with a hammer mill overcomes the disadvantage of the dry mixing method, ie particle size control. Other important improvements can also be achieved by forming the lubricating powder in a completely different way.

Hammer milling equipment is typically quite large and is constructed of steel or other metal.
When the equipment is conditioned to ambient room temperature, ie, about 60 ° F. to 70 ° F., there is a high efficiency cooling radiator for the lubricating composition in grinding the lubricating composition. If necessary, the device can be further cooled, for example by circulating liquid nitrogen in the network of internal channels supplied for cooling purposes. Simply injecting liquid nitrogen into the inlet hopper of a conventional grinder along with a lubricating material is also a rudimentary but effective cooling method. By this temperature control, the process can be optimized in terms of particle size control. This is because many lubricating components are sticky or semi-solid when subjected to conventional heat-generating milling processes, but keep dry solids at low temperatures.

When the lubricating composition is produced in this manner, a lubricating powder having a very narrow particle size distribution can be produced, which has better fluidity due to a more uniform particle size and produces little or no dust. , Avoids the undesirable consequences of dry mixing methods.

Lubricating powders produced by the melt mixing process are also physically different because the individual particles are a heterogeneous composition. Visual inspection of lubricating particles produced by the melt mixing process reveals that the fusible component melts to form a solid matrix in which the non-melting component (eg, graphite) is fixed. This matrix structure is such that separate particles of the non-melting component are fixed in the matrix of the fusible component, but the structure is at a magnification of 20: 1 to 100: 1 due to the color difference between the lubricating components. You can see clearly.

While the melt mix milling process is effective in overcoming many of the drawbacks of the dry mix process, its effectiveness comes at the expense of a very complex and expensive multi-step process. Moreover, the process also has functional drawbacks. On the other hand, typical equipment used to melt mix lubricating components, i.e. vessels heated by oil filled jackets, is used to melt the highly desirable component of the lubricating composition, metal soap (e.g. tin soap). It cannot produce a high enough temperature. On the other hand, typical milling equipment (unless operated in a refrigerated environment, or without a built-in refrigeration system) has temperatures up to temperatures at which low-melting components (eg waxes) become sticky and can no longer be processed as powders. The lubricating composition is heated.

Alternatively, the lubricants of this invention are formed by forming a homogenous melt of the components as described above, and spray drying the melt to the desired particle size in the conventional manner and melt mixing as described above. Heterogeneous particles may be produced that have a matrix structure similar to that produced by the milling process.

These lubricant making processes of the present invention make it much easier to control the particle size of the composition and not only optimize the process of die and workpiece application, but also improve the performance of the lubricating composition. Since the lubricating particles are ground or spray dried from an essentially homogeneous mass, the lubricating components are much more evenly distributed in the composition than is achieved using conventional dry mixing techniques.

The third method of preparing a carrier-free powder lubricating composition in which the particles have a substantially uniform size is wet granulation. In the wet granulation method, the lubricating components are premixed in, for example, a Patterson-Kelly granulator or V mixer to obtain a homogenous mixture. Thereafter, a sufficient amount of aqueous binder is added to the homogeneous mixture to produce a slurry. The binder may be a thickening agent such as polyvinylpyrrolidone (ISP Technologies / GAF, Wayne, New Jersey, PVP K series, eg K30.
(MW = 40000), K60 (MW = 16000)
0), K90 (MW = 360000)) or hydroxymethyl cellulose (eg, QP300 cellose (ce)
llosize, Union Carbide, Danbury, CT), which forms bridges between adjacent particles when dried, but may also contain them. Optionally, the binder is one or more nonionic surfactants such as diisopropyl adipate (Van Dyke Therapy 2).
30 (Van Dyke Ceraphy 230); octyldodecyl stearoyl stearate (Seraphy 847); or polyoxyethylene ethers such as Triton N-1.
01 (Triton is Rohm and Haas)
Haas) is a registered trademark of the company), preferably 0.1
To 0.3 wt% may be contained. Various polyoxyethylene ethers are available from Sigma Chemical (Sigma Che
mical), St. Louis, Mo. under the Triton mark. The slurry is poured onto a cookie sheet and dried in an oven, preferably set at about 210-220 ° F. The dried slurry breaks into chips,
Grind into lubricating particles of heterogeneous composition and separate by particle size. Separation can be accomplished by passing particles through a 40 mesh and 80 mesh filter, passing through 40 mesh but retained by the 80 mesh filter. The retained particles provide a carrier-free powder composition in which the lubricating particles are of substantially uniform size.

A fourth method of preparing a carrier-free powder lubricant composition having particles of substantially uniform size is agglomeration. It has been found that agglomerating the particulate lubricating components to form agglomerated particles of a heterogeneous composition is beneficial in that it eliminates all of the above-described melting and slurry steps and their attendant drawbacks. Various techniques for agglomerating particles are known in the art. For example, Ulmann's Encylopedia of Industrial Chemistry,
VCH Publishing Company, NY, NY 1988, Volume B-2, 7-1
See pages 7-37. This is incorporated herein by reference.

The process of forming the agglomerated lubricating particles may be carried out either in the presence or absence of a binder; preferably in the presence of a binder; more preferably an aqueous binder; most preferably a polymeric binder (ie a booster). It is carried out in the presence of an aqueous binder containing a sticky agent) and / or a nonionic detergent. For the purposes of the present invention, the phrase "aqueous binder" comprises all binder solutions in which more than 50% of the solvent is water, preferably more than 75%, more preferably more than 90%. Means The balance of the solution solvent, which is essentially an aqueous solution, is a non-interfering, water-miscible organic solvent. Typical water-miscible organic solvents are alcohols having 1 to 3 carbon atoms, polyols such as ethylene glycol, propylene glycol or glycerin, polyethylene glycol having a molecular weight (MW) of 200-600, acetone,
Tetrahydrofuran (THF), dimethyl sulfoxide (DMSO) and the like are included. Other water-miscible organic solvents are well known to those of ordinary skill in the art. However, many of these solvents must be taken care to prevent the build-up of static electricity in the device which can be a source of ignition.

The binder components used to efficiently deposit the component lubricating particles in the agglomeration process of the present invention include natural gums or products including algin, starch, and xanthene gum; methyl cellulose, hydroxypropyl methyl cellulose and glyoxal hydroxymethyl cellulose. Cellulose derivatives containing; Polymers containing polyvinylpyrrolidone (PVP) and sodium carboxymethyl starch; Compressibility enhancers containing microcrystalline cellulose and bentonite; Matrix binders such as corn syrup, wax, sorbitol, paraffin, shellac alcohol and polymethacrylate. Etc. are included. Many other chemical binders are available. The binder component is a type of agglomeration,
The choice may be based on many factors such as viscosity, concentration, cohesive strength and drying properties.

When agglomerated in the presence of a binder, many individual particles of different composition, size, and surface characteristics coalesce and adhere to form larger particles of various constituent particles. The strength and size of the resulting agglomerated particles depends on the binding properties, binder properties and stirring method of each individual constituent particle.

In the present invention, the various particulate components are selected based on their performance in the heterogeneous particulate metalworking lubricating composition. From an economic standpoint, it is desirable to utilize the agglomeration process of the present invention to form (heterogeneous) carrier-free powder metal working lubricant compositions. Various constituent particles may be purchased in a suitable particle size range to facilitate control of the particle size range of the carrier-free powder lubricant composition.

Depending on the relative size of the constituent particles, cohesion is very small due to coalescence between particles of equal diameter, layering of larger particles with smaller particles or due to partially filled binder drops. Described as the absorption of particles.

It is possible to predict a rough relationship between the amount of binder, the stirring intensity and the process time, and the selection of the optimum parameters requires routine experimentation with each particular part of the aggregator. To do. Agglomeration devices useful in forming the agglomerated particles of the present invention include drum and disk blenders, pin mixers, spray dryers,
It includes a compressor and a bed granulator with a fluidized bed or swallowing mouth.

In a typical drum blender agglomeration process, agglomeration can be expressed as a function of dimensionless Stokes number (Stv), with the equation:

[Equation 1] (In the formula, m = mass of particles (mg), U = fluid binder viscosity (cps), a = particle radius (micron), p = particle material density (g / m ³ ), w = drum rotation speed (rpm) ) U ₀ = relative particle velocity = 2 aw (drum coarse) (m / s).

Usually, a particle size distribution is encountered in a one-component system. The various constituent particles have various shapes, surface contours, radii,
In a multi-component particle system that has mass and density,
Some experimentation is required to achieve effective aggregation. The two variables that are most easily adjusted are the fluid binder viscosity (U) and the relative particle velocity (u) due to the speed of stirring.
₀ ).

In Examples 22-23 below, a carrier-free powder metalworking lubricant having a substantially uniform diameter was tested on an experimental or commercial scale V liquid-solid blender / granulator (Patterson). −
Kelly Co., East Stroudsburg, PA) (hereinafter referred to as "granulator") was used and prepared by aggregation. This granulator performs batch process agglomeration. However, continuous process flocculators can also be used. In the agglomeration process, the particulate components of the lubricating composition were added to the granulator chamber and dry blended for a time sufficient to ensure a homogenous mixture. Then, the binder solution was added all at once while dry mixing the granulator. The commercial scale V-blender utilized in some examples was modified to allow excess moisture to escape during processing. The modification is to make a small hole about 1/4 "in diameter at the top of the conveyor plate, cover the hole with a filter paper of sufficient pore size to allow air to escape while retaining virtually all fines, and liquid. It consisted of pumping relatively dry air through the dispersion bar to reduce the water content of the agglomerated particles therein.

Maintaining the water content of the product as low as possible during coagulation, preventing caking, avoiding the condition in which microorganisms can grow, and further applying the lubricant in a free-flowing state to which the powder coating apparatus can be effectively applied. It is desirable to maintain. According to the method of the present invention, the water content of the agglomerated metal working lubricant is preferably less than 15% by weight; more preferably less than 2% by weight, most preferably 0.5% by weight.
Is less than. If desired, anti-caking agents such as silica, tricalcium phosphate, calcium aluminum silicate and microcrystalline cellulose may be added in amounts up to about 10% by weight to improve the flow properties of the agglomerated particles.

The following were used for the following examples: graphite 3731, average particle size 50 microns, S
F33 as Superior Graphit
available from e); sodium stearate, average particle size 3
Less than 25 mesh, Witco Chemica
l) available; zinc stearate, average particle size <325 mesh, available from Witco Chemical.

Example 22 Raw Material Weight% Granular Component 1 Graphite 3731 14.50 2 Sodium Stearate 24.00 3 Cargill 30-3065 9.60 4 Pluracol E-4000 19.23 5 Zinc Stearate 28.80 Binder Component 1 Water 3.67 2 QP300 Cellosize 0.16 (Hydroxymethyl cellulose) 3 Triton N-101 (Nonionic surfactant) 0.04 100.00%

In the proportions listed above for the binder components,
Premixed until clear and thick. The premix was set aside. The granular components were added in the order described above in the dry state to the aggregator and mixed dry for one and a half hours. The binder was then added to the aggregator, taking care not to hit the wall or the sweep bar. The contents of the aggregator were stirred for 4 hours at a drum rotation speed of 15 rpm. Then, the obtained aggregated particles were separated by size through a 40 mesh screen and an 80 mesh screen. The substantially uniform particles of the carrier-free powder metalworking lubricant of the present invention are 40
Pass through a mesh screen, but retained by an 80 mesh screen. In terms of relative particle size, this is about 170 microns to about 42 for substantially uniform particles.
It is meant to have a diameter in the range of 0 micron. Aggregated carrier-free lubricating particles in this size range were properly delivered to the metal surface with minimal dusting.

Examples 23-32 Examples 23-32 are 3 pound batches (Example 23-2
9) It also describes the lubricating composition particle size distribution as a function of time for a 200 pound batch (Examples 30-32). Examples 23-32 use the same granular components 1-5 listed in Example 22, but with varying amounts and compositions of binder solution. FIG. 1-10 shows Example 23-
Corresponding to 32, the particle size distributions are compared graphically as a function of aggregation time. The particle size distribution at time zero reflects the particle size distribution after mixing and before binder addition. As Example 24 reflects, if the raw material is not ground prior to agglomeration, there is a high proportion of larger particles distributed at time zero. The highest yields of ideal sized particles were obtained as described in Example 32.

[0131]

[Table 1]

[0132]

[Table 2]

[0133]

[Table 3]

[0134]

[Table 4]

[0135]

[Table 5]

[0136]

[Table 6]

[0137]

[Table 7]

[0138]

[Table 8]

[0139]

[Table 9]

[0140]

[Table 10]

The process of Example 32 resulted in a 62% yield of a carrier-free powder lubricating composition having a substantially uniform diameter. When the amount of binder solution was reduced from 5% by weight (Example 31) to 3% by weight (Example 32), Example 32 had 40% of ideal size particles compared to Example 31.
%Increased.

As is apparent from the above, the individual particles of the lubricating composition produced by the agglomeration process are essentially inhomogeneous in composition and are therefore physically different from the particles produced by the dry mixing process. It is also physically different from the particles produced by the melt mix milling process and the melt mix spray drying process. Because agglomerated particles are aggregates of the individual lubricating components that melt in the absence of a molten matrix into a heterogeneous mass. Although physically different, the lubricating composition produced by the melt-mix grinding process and that produced by the agglomeration process are:
They do not show functional differences that are easily observed.
That is, their performance seems to be equivalent.

Each of the processes of the present invention (whether molten phase, dry slurry, or agglomerates) can produce individual particles of heterogeneous composition, producing more uniform dielectric properties than strictly dry mixed compositions. Have.

One benefit of producing a carrier-free powdered lubricating composition of substantially uniform size is that when the lubricating particles are sprayed onto the die or workpiece at higher temperatures, the particles melt and melt substantially. Is to form a uniform lubricating film. When the particles are produced in this way, the lubricating components are more evenly distributed on the die or workpiece surface, improving adhesion resistance and forming a more uniform metal flow along the surface. The cleanliness of the composition is improved by the more uniform distribution of the resin included for that purpose. Further, since there are no carriers, flushing is eliminated or minimized.

Application of the carrier-free powder lubricating composition of the present invention can be accomplished using conventional powder coating equipment, essentially at ambient pressure. For example, in conventional electrostatic powder coating equipment, it is well known that a fluidized bed of powder is replenished and exposed to a spray wand having an electrode at the tip. By the time the powder arrives at the applicator wand tip (typically about 20 feet distance), the device injects air into the powder at a fairly low pressure to form a fluidized bed and carry the powder (ie, the powder stream). ) Is done at a fairly low, essentially ambient pressure. Die (maintained on the ground) due to the charge given to the powder by the electrodes
It is accelerated to carry powder. Once carried on the die surface, the lubricating powder is retained thereon by virtue of the adhesive properties of at least one component contained for deposition purposes.

Alternatively, conventional powder coating equipment, whether electrostatic or non-electrostatic, has
It may utilize a gravity fed hopper as a powder source. Such an apparatus may be particularly useful when utilizing a wide range of particle sizes or lubricating powders of relatively heavy lubricating mixtures that do not readily form a fluidized bed. understood. Further, when utilizing such gravity feeders, the optimum result in delivering powder to the spray wand is whether the lubricating particles have a substantially spherical or substantially smooth surface, and most preferably It turns out that you can get it when you have both. Due to these properties, the lubricating particles melt or are wedged against one another upon impact, reducing the tendency to block the flow of material and allowing the lubricating particles to flow more easily. From the point of view of optimizing both the shape and the surface properties, the above-mentioned manufacturing method employing spray drying is preferred. This is because spray drying is essentially spherical in shape and produces substantially smooth particles.

The agglomeration process of the present invention is preferred from the standpoint of obtaining substantially uniform particles of inhomogeneous composition without the need for a melting step.

In the process of the present invention, the lubricating powder is coated on the work piece or die in a coating-like manner. The lubricant is not processed on or in the die or workpiece. Rather, the process is similar to painting a lubricant on a die and not driving it onto the surface.

From the above description and examples it is clear that the objects of the invention have been achieved. Only some specific examples have been given, and various other variants will be apparent to those skilled in the art. These other choices and variations are equivalent and are considered to be within the scope of the invention.

[Brief description of drawings]

1 is a graphical representation of the time course of particle size distribution during the process of Example 23. FIG.

FIG. 2 is a graphical representation of particle size distribution over time during the process of Example 24.

FIG. 3 is a graphical representation of the change in particle size distribution over time during the process of Example 25.

FIG. 4 is a graphical representation of particle size distribution over time during the process of Example 26.

FIG. 5 is a graphical representation of the change in particle size distribution over time during the process of Example 27.

FIG. 6 is a graphical representation of the time course of particle size distribution during the process of Example 28.

FIG. 7 is a graphical representation of the time course of particle size distribution during the process of Example 29.

FIG. 8 is a graphical representation of the change in particle size distribution over time during the process of Example 30.

FIG. 9 is a graphical representation of the time course of particle size distribution during the process of Example 31.

FIG. 10 is a graphical representation of the time course of particle size distribution during the process of Example 32.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C10M 105: 22 119: 02 107: 04) C10N 10:02 10:04 20:06 Z 8217-4H 40:24 50:08 70:00 (72) Inventor Juan M. Yulibe 1551 Pass and Covina Road, Ballinda, CA 91744, USA (72) Inventor John M. Hogan, USA 90804 Lo, CA, USA Ing Beach, East Nineth Street 4213 (72) Inventor Richard A. Persinger, United States 60190 Arbor Court Owen, Winfield, Illinois 524 (72) Inventor James F. Miller United States 91748 California State Roller De, Heights, Monteru Court 19002 No. (72) inventor Ramesh TA Nabarattonamu United States 60544 Illinois Plainfield, West Mary Lane 25033 No.

Claims (24)

[Claims] 1. A carrier-free powder metal working lubricating composition comprising at least two types of granular lubricating components, comprising:
A lubricating composition formed by a method comprising the steps of: (a) forming a dry additive mixture of the particulate lubricating component; and (b) stirring the additive mixture to form agglomerated particles. 2. The composition of claim 1, wherein the agglomerated particles are formed in the presence of an aqueous binder. 3. At least one particulate lubricating component is a polymeric resin having highly polar functional groups in the polymer backbone, the resin being soluble under strong acid or base conditions,
The composition of claim 1 which is solid at room temperature. 4. A composition according to claim 1, wherein the at least one particulate lubricating component is selected from the group consisting of metal soaps, graphite, ceramics, natural and synthetic waxes, glasses, fatty acids and mixtures thereof. 5. The composition of claim 1 having relatively little or no agglomerated particles 50% larger or smaller than the average particle size. 6. A composition according to claim 1, wherein the water content of the agglomerated particles is lower than 15% by weight. 7. A carrier-free powder metalworking lubricating composition in which the individual lubricating particles are of a substantially heterogeneous composition. 8. A step of agitating the additive mixture under conditions sufficient to (a) form a dry additive mixture of the particulate lubricating component and (b) form agglomerated particles of the carrier-free powder metalworking lubricant. A method for forming a carrier-free powder metal working lubricating composition from a granular lubricating component comprising: 9. The additive mixture of the lubricating component is metal soap, graphite, ceramics, high melting point polymer resin,
At least one selected from the group consisting of natural and synthetic waxes, glasses, fatty acids and mixtures thereof.
The method of claim 8 comprising a solid lubricant of a type. 10. The method of claim 8 further comprising the step of adding a binder to facilitate adhesion of the particles to each other. 11. The method of claim 10 wherein the binder is essentially an aqueous solution. 12. The method according to claim 11, wherein the stirring is performed by loading the granular lubricating composition into a container and tumbling the container by mechanical means. 13. The method according to claim 11, wherein the stirring is carried out by injecting a vaporizing gas vapor into the dry addition mixture. 14. The method of claim 11, wherein the binder is added by spraying finely divided droplets. 15. The method of claim 11 wherein the binder component comprises a thickener. 16. The method of claim 15, wherein the thickening agent is one of the group consisting of glyoxal hydroxymethyl erulose, polyvinylpyrrolidone, xanthene gum, hydroxypropylmethylcellulose, methylcellulose, algin and mixtures thereof. 17. The method of claim 11, wherein the solution comprises a nonionic surfactant. 18. The method of claim 17, wherein the nonionic surfactant is present in an amount of about 0.3% to about 0.1% by weight of the binder. 19. The method of claim 11 wherein the water content of the agglomerated particles is less than about 15% by weight. 20. The method of claim 19, wherein the water content of the agglomerated particles is less than about 5% by weight. 21. Further retaining the agglomerated particles by passing the agglomerated particles through a 40 mesh screen followed by an 80 mesh screen and then through a 40 mesh screen but not through an 80 mesh screen, 11. The method of claim 10, comprising the step of obtaining an agglomerated carrier-free powder metalworking lubricant of substantially uniform particle size. 22. The substantially uniform particle size of the agglomerated carrier-free powder metalworking lubricant having an average particle size of from about 170 microns to about 420 microns.
The method described. 23. A carrier-free powder metalworking lubricating composition comprising from about 2 to about 30 weight percent sulfur and at least one component having adhesive properties at forging temperatures. 24. The composition of claim 23 comprising about 5 to about 30% by weight sulfur, graphite, gilsonite, and polyethylene wax.