NL8000569A - LUBRICANT FOR USE IN DEFORMING, AND METHOD FOR DEFORMING FERRO AND NON-FERROUS METALS USING THIS LUBRICANT. - Google Patents

Description

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Lubricant for use in the deformation process and method for deforming ferrous and non-ferrous metals using this lubricant

The deformation is a method by which the shape and physical properties of a metal can be changed. The method involves placing a piece of metal (usually heated) between the halves of a mold, which is then closed by impact or pressure. The machining causes controlled plastic deformation of the metal, penetrating the cavities of the mold. This material flow not only changes the shape of the metal, but also increases the density and uniformity of the metal, improves grain structure and produces shape-matched grain flow. The workpiece obtained has properties superior to those obtained by other methods, making such shaping essential when workpieces with excellent behavioral properties are required.

One of the critical components of such a molding system is the lubricant, which separates the die from the workpiece. As with all lubrication operations, it is essential that this lubricant counteracts wear of the extremely expensive deformation dies and that it minimizes energy loss or a wide range of operating conditions.

The lubricant must also ensure a high-quality surface when deforming, and no more harmful residues must remain on the mold, nor should corrosion occur.

As the shape has recently increased towards safer and more reliable machine constructions, the deformation has to be applied to more difficult to process materials, at higher temperatures and pressures, to produce more complex moldings. Although oil-based lubricant mixtures, which are effective under extreme conditions, have been developed, their properties appear to be in serious conflict with regulations regarding personal safety and environmental protection. The oil-based lubricants are normally flammable and can ignite significantly below the usual operating temperatures. The normal operation leads to the development of a sooty smoke, which is unpleasant and often poisonous. In addition, cleaning the workpieces and the mold requires solvent washing, yielding large amounts of wax liquid, which, given the economy of recycling and the desire to protect the environment, can lead to serious problems.

The ecological problems associated with oil-based hot-forming multi-agents have led to the development of water-based mixtures. A clear advantage of a water-based lubricant mixture is that cooling can be accomplished by evaporation of water on the hot molds, often requiring internal cooling of the molds. Previous attempts to prepare water-based mixtures containing graphite, clay minerals, iron oxide and molybdenum sulfide E.P. as well as anti-wear additives were often effective because the water did not suitably wet the metal surfaces.

A water-based lubricant is described in U.S. Patent 2,735,814, wherein a deformation die lubricant contained tear, graphite and water. According to U.S. Pat. No. 2,921,874, fatty acids are generally unsuitable as deforming additives unless they are combined with an organic acid reagent, an organic solvent, and water. Fatty acids with more than 7 carbon atoms were used.

U.S. Pat. No. 3,313,729 used a mixture of pyrophosphate or sodium tetraborate, a fatty acid soap having from 8 to 22 carbon atoms, preferably from 35 to 18 carbon atoms, to provide a dry layer on the metal 800 0 5 69 I * 3 * mold for cold forming. A similar dry film-forming lubricant is described in U.S. Patent 3,375,193 and based on a water-soluble colloid, a fatty acid soap containing 12 to 22 carbon atoms, an alkali metal tartrate and inorganic pigments.

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A glass molding lubricant is described in U.S. Pat. No. 3,507,791 and includes an aqueous dispersion of a fatty acid of 10 to 32 carbon atoms, alkanolamine, a water-soluble alcohol and water. U.S. Patent 3,983,042 describes a water-based hot-deformation lubricant containing graphite, organic thickener, sodium molybdate and sodium pentaborate.

It is clear from the above that fatty acids and fatty acid soaps have been widely used as antiwear and lubricant additives in deformation mixtures. These fatty acids and soaps generally have preferably 12 to 20 carbon atoms. Recently, the Metalprep Department of Pennwalt Corporation has marketed a hot-forming lubricant containing the alkali metal salt of azelaic acid in aqueous solution. 2Q However, the use of azelaic acid has some serious shortcomings, which do not occur with adipic acid in water-based hot form lubricants. The main problem with azelaic acid salts lies in that the deformation die is not effectively wetted at the elevated temperatures of, for example, 315 to 425 ° C, while adipic acid salts readily wet the die at these temperatures. In addition, salts of azelaic acid in high temperature molding operations will smoke and even decompose before actual deformation, while the adipic acid salts give relatively little smoke and are stable at high temperatures.

It has now been found a lubricant mixture and a hot deformation process for ferrous and non-ferrous metals, based on an aqueous solution of adipic acid salts, obtained by reacting adipic acid with an alkali metal or alkaline earth metal 800 0 5 69 JT · F 4 metal hydroxide. The usual lubricant additives are also present. In an embodiment of the invention using a dispersion, graphite is used in combination with adipic acid salts as the principal lubricants.

The lubricant mixtures and the deformation processes of the invention are based on the use of aqueous solutions and dispersions, in which salts of adipic acid are the main lubricants. Alkali metal and alkaline earth metal-10 hydroxides are used to convert the adipic acid into adipates. Graphite is used in the blends and in adipate processes where heavier deformation conditions are involved and where additional die life for optimum lubrication is required. As required, at least one and generally several conventional lubricant additives are used, for example, organic thickeners, surfactants, including suspending agents, dispersants, wetting agents and emulsifiers, E.P. additives, corrosion inhibitors, germicides, anti-wear agents, foaming control agents, pigments, dyes and perfumes.

The adipic acid is used in the lubricant mixture according to the invention at a concentration of about 1 to 35% by weight. The alkali metal and alkaline earth metal hydroxides are present in a concentration of about 0.5 to 19% by weight. The usual lubricant additives are present in a concentration of about 0.05 to 25% by weight. The rest of the mixture consists of water. If graphite is present in the mixtures, it is used in a concentration of 5 to 25% by weight.

Many hot form lubricants based on oil will evaporate quickly or cause fire and smoke. Many water-based hot deformation lubricants will cause smoking, unpleasant odors and toxicity problems, or leave harmful residue on the dies. The mixing requirement and the deformation process, using 800 05 69 * 5 * * * adipic acid, solve these problems to a large extent.

The adipic acid is used as the main lubricant in the mixtures according to the invention. It is present in the form of an alkali or alkaline earth metal soap if the water evaporates rapidly during the deformation. The adipic acid is present in a concentration between about 1 and 35% by weight. The adipic acid used is of commercial or technical quality and can be supplied by E.I. du Pont, Allied Chemical, Celanese and other suppliers.

The aqueous solution and / or dispersion contain alkali metal or alkaline earth metal hydroxide in an amount which is not quite sufficient to convert all the adipic acid to the corresponding salts commonly referred to as soaps. This facilitates solubilization of the adipic acid. Generally, the alkaline earth metal or alkali metal hydroxide is used in an amount of about 0.5 to 19% by weight. The actual amount used is determined by chemical control to ensure that the solution or dispersion remains neutral or weakly alkaline (pH 7.0 to 8.5} 20 and does not contain too much free alkali. Sodium hydroxide deserves de and preference / is usually added in the form of an aqueous solution.

When graphite is used in the blends and in the process of the invention, it is present in an amount of from about 5 to 25% by weight. Graphite is commercially available from a number of suppliers.

At least one conventional lubricant additive will be present in the hot-forming mixtures, and often several of these are used as required by the appropriate hot-forming method. The conventional lubricant additive is generally present in the blends of the invention at a concentration of about 0.05 to 25% by weight.

The usual lubricant additive, which is almost always used in the mixing process and method of the invention, is 800 0 5 69 m y 6, consisting of an organic thickener. The organic thickeners are selected from the group consisting of substantially water-dispersible modified cellulose derivatives, such as methyl cellulose, soluble ether cellulose, sodium carboxymethyl cellulose, ammonium carboxyethyl cellulose, methyl ethyl cellulose, hydroxymethyl cellulose, potassium carboxylylulose, potassium carboxylylulose, potassium carboxyhexulose, potassium carboxyhexulose, potassium carboxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, cellulose, cellulose, hydroxyethyl cellulose, cellulose, cellulose, hydroxyethyl cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, sodium cellulose, cellulose, cellulose, hydroxyethyl cellulose, cellulose. Casein and alginates, such as sodium alginate, are satisfactory thickeners. Bentonite is also a satisfactory thickener.

Other suitable water-soluble thickeners include polymethacrylates, polyvinyl alcohol, starch, gelatin, gum arabic and polysaccharides.

The preferred organic thickener is hydroxyethyl cellulose and it is commercially available from Hercules Chemical under the trademark Natrosol 250 HR and 250 HHR.

These thickeners promote solubilization of the other ingredients, enhance the adhesion and wetting of the lubricant mixture to the workpieces. The preferred concentration of organic thickener in the lubricant mixture is about 1% by weight.

Surfactants are advantageously used in the aqueous system to promote wetting of the surface of the dies and in certain cases also to promote wetting of the workpieces with the lubricant mixture, to help water-insoluble components such as graphite, if any , dispersing, suspending and emulsifying and to equalize the lubricant mixture on the workpieces and dies. The wetting agents, dispersing agents, emulsifying agents and leveling agents for aqueous systems are well known. Many examples of each of these are described in McCutcheons Detergents and Emulsions, 1978 edition.

Examples of such wetting and dispersing agents are: a polyoxyalkylene derivative of sorbitan monostearate 80 0 0 5 69 * 7 with a molecular weight of about 1300 (Tween 60, marketed by Atlas Powder Co.) polyoxyethylene sorbitan monooleate (Tween 80, in the marketed by Atlas Powder Co.) sorbitan monostearate (Span 60, marketed by Atlas Powder Co.) 5 sorbitan monooleate (Span 80, marketed by Atlas Powder

Co.) oxyethylene nonylphenol (Tergitol NPX, marketed by Union Carbide Co., composition about one oxyethylene per mole of nonylphenol) polyoxyethylene, nonylphenol (Tergitol NP14, marketed by about 14 moles oxyethylene mole nonylphenol), polyoxyethylene nonyl phenol (Tergitol NP35, marketed by Union Carbide Co., composition about 35 moles oxyethylene mole nonylphenol), sulfated castor oil (marketed by Baker Caster Oil Co.) alkylarylsulfonate (Duponol G, marketed by 15 duPont de Nemours & Co.), alkylarylsulfonate (Textilana MW, marketed by Textilana Corp.) polyoxypropylene glycol (Pluronic L62, marketed by Wyandotte Chemicals Corp.) and fatty alkanolamides (Emcol 510QT , marketed by Witco Chemical Co.).

Other comparable wetting agents can be used.

As mentioned, for comparison of uniform thickness, leveling compounds can be added to the aqueous lubricant to remove brush marks and obtain a smooth, even surface. Examples of such compounds are carboxymethyl cellulose, tricresyl phosphate, glycerol, lecithin, ethylene glycol and sorbitan borate.

Typical emulsifiers are the olefin C 2 to C 6 derivatives of partial fatty acid esters of aliphatic polyhydric alcohols, a fatty alcohol, a fatty acid, an aliphatic amine and alkyl phenol, and mixtures thereof. The partial fatty acid esters include the C8 -C18 aliphatic polyhydric alcohols having about 3 to 12, for example 3 to 8, carbon atoms and about 2 to 8 hydroxy groups per molecule. The mono-, di- and tri-esters of sorbitol are very useful. The fatty acids which react with the 800 0 5 69 & 8 ° lefine oxides include linear aliphatic monobasic acids with 10 to 20 carbon atoms. Ethylene oxide derivatives of stearic acid and oleic acid are preferred. The etoxylated derivatives of the normal primary alcohols with 10 to 18 carbon-5 atoms are very useful. Aliphatic amine derivatives of the linear C 1 to Q 2 are also useful. Alkylphenols which react with ethylene oxide or propylene oxide include the mono and dialkyl phenols having about 8 to 12 carbon atoms in the alkyl group, such as nonylphenol and di-nonylphenol.

The preferred concentration range of surfactant in the blends is about 0.5 to 2.0 wt. %.

For difficult molding operations under very high pressures, it is sometimes desirable to include E.P. additives, such as molybdenum disulfide and sodium molybdate, in the mixtures.

Pigments can be used in the lubricant blends to improve lubrication, act as a separator, and aid cooling of the mold by acting as insulation. Graphite is the most commonly used material of this kind. Other useful and suitable pigments are lithopone, talc, calcium carbonate, zinc oxide, zinc carbonate, mica, magnesium carbonate and titanium dioxide.

Corrosion inhibitors useful in the process of the invention are alkali metal nitrates and alkali metal nitrites.

Benzotriazole is effective in preventing the corrosion of copper. A preferred concentration of corrosion inhibitor is about 0.1% by weight.

Germicides are desirable in the aqueous systems to prevent the growth of bacteria during storage and transportation of the concentrated aqueous systems and also to counteract this during storage in the feed tanks of the dilute use solutions. Dowicil 75 and sodium omadine are suitable germicides. A preferred germicidal concentration is about 0.1% by weight.

35 Typical foaming control means 800 0 5 69 ♦ 9

Sr are linear aliphatic alcohols with 6 to 12 carbon atoms.

A preferred concentration of such an agent is about 0.5% by weight.

Dyes can perform various useful functions in the aqueous hot deformation lubricants. For example, they are means of identification to indicate the supplier of the lubricant. They can also be used to indicate the pH of the aqueous solutions if of interest. Orcoacid alphazurizine 2G dye, Blue dye, Metford Chemical's 10 Green dye and Bismark brown dye are suitable. The inclusion of perfume is made exclusively for aesthetic reasons. Dyes and perfumes are added in amounts that are pleasant to the touch.

The aqueous hot form lubricants of the invention are provided in concentrated form, and the lubricants can be used in the net concentration for the most difficult molding operations. In less difficult shaping operations, the concentrated lubricant can be diluted with water to adapt it to the special needs of the particular operation. The amount of diluent can only be determined by actually working on the molding press or with the particular workpiece. Suitable shaping operations have been performed with up to 15 volumes of water to one volume of concentrated lubricant.

The lubricant mixture can be formulated in the manner described hereinafter. A chain, equipped with stirrer and with either internal or external heating and cooling is necessary. Stainless steel is a preferred metal for the mixing vessel. The vessel is filled with cold water and organic thickener is added with stirring until dissolved. After that, part of the alkali metal hydroxide is added, followed by alternating addition of alkali and adipic acid. The temperature is allowed to rise to about 82 C. Cooling may be necessary to prevent the solution from boiling. The alkali metal or alkaline earth metal hydroxide is added until the acid number is between 0.0 and 0.3. The solution should not contain free allakli.

Finally, the colorant dissolved in hot water is added, as well as other conventional lubricant additives as required. The final solution is a clear liquid with a semi-gelled appearance.

When graphite is used in the lubricant mixture, it is preferable to dissolve the adipic acid and alkali metal hydroxide before adding graphite and organic thickeners. The surfactants, such as dispersants, wetting agents and emulsifying agents, must be added for graphite and the organic thickener. The best embodiment will be apparent from the following examples.

Example I

An effective lubricant mixture in the form of a solution is composed of the following ingredients, the percentages being by weight percent.

a

organic thickener 1% sodium hydroxide (50% solution 13.5% 20 adipic acid 12.5% dye 0.05% germicide B 0.05 water residue A-Natrosol 250 H.R. hydroxyethyl cellulose.

25 B-Dowicil 75.

This mixture is very economical because it is important for diluting with water.It is also biodegradable, which greatly facilitates its discharge. It also has the advantage that it is not adversely affected by freezing, provided it is thawed before use.

Example II

A graphics-containing form of the hot-forming lubricant is composed of the following components, in percent by weight.

8000569 r 11 '-Τ'

Adipic Acid 15, Q% Sodium Hydroxide (50% Solution) 15.2% Graphite 15.0% & Germicide 0.07% 5 Organic Thickener 1.0%

Q

dispersant 1.0% water, residual A mixture of sodium omadine and Dowicil 75.

B-Natrosol 250 HHR.

10 C-Polywet WD-1.

The lubricant mixtures described above can be applied to the molds in any suitable manner, for example by dipping, soaking, by circulating the lubricant over the mold or by spraying. Application by spraying is most effective. The molding operation consists of bringing the workpiece to the molding machine, applying an effective amount of lubricant to the mold, closing the mold, applying pressure to the mold, opening the mold and removing the molding. The effective amount and a lubricating amount. This amount can only be determined by practical tests, since the effective amount of lubricant required depends on many variables, such as the temperature, the molding pressure, the hardness of the workpiece, whether or not it is difficult to shape, the 25 design required time and other factors.

Example XII

The molds of a molding press were pre-coated with the lubricant mixture of Example I at the net concentration while being heated to 812 ° C. Three dies work -30 in time. A 10 cm diameter thick-walled tube was brought to the mold and the mixture of Example I, diluted with an equal volume of water, was sprayed onto the mold. The dies were closed at a pressure of 17.5 MPa and elbows 90 o with a large radius were formed.

35 Continued molding showed no smoke, no fire, and no unpleasant odors occurred. Good lubrication and adhesion of the lubricant was obtained and only minimal splashing occurred. There was no unwanted accumulation of lubricant on the dies. Occasionally, a powder-like residue appeared, which could be easily removed by rinsing with steam or hot water. The nozzles did not get clogged.

800 0 5 69

Claims (9)

Lubricant mixture for use in hot-forming, characterized in that it is achieved by reacting adipic acid, about 1 to 35%, with alkali metal or alkaline earth metal hydroxide, about 0.5 to 19%, to form adipic acid salts and by adding at least one conventional lubricant additive selected from the group consisting of organic thickeners, wetting agents, suspending agents, germicides, foam control agents, EP additives, pigments, corrosion inhibitors, dyes and perfumes, in amounts from about 0.1 to 10%, the remainder being water and all percentages being weight percent. Lubricant mixture according to claim 1, characterized in that the alkali metal hydroxide consists of sodium hydroxide and that the organic thickener is hydroxyethyl cellulose. Lubricant mixture comprising 12.5% adipic acid, 1. organic thickener, 6.8% sodium hydroxide, 0.05% dye, 0.05% germicide and the balance water, all percentages being by weight. Lubricant mixtures, characterized in that it is prepared by the reaction of adipic acid, about 1 to 35%, with alkali or alkaline earth metal hydroxide, about 0.5 to 19%, to form adipic acid salts, and further containing about 5 to 25% graphite, at least one lubricant additive, selected from the group consisting of organic thickeners, wetting agents, suspending agents, germicides, foam control agents, EP additives, pigments, corrosion inhibitors, dyes and perfumes, in amounts of 0, 1 to 10%, and the remainder being water, with all percentages being 30% by weight. Lubricant mixture according to claim 4, characterized in that the alkali metal hydroxide is sodium hydroxide and the organic thickener is hydroxyethyl cellulose. 6. Lubricant mixture, characterized in that it comprises 15% adipic acid, 8.1% sodium hydroxide, 15% graphite, 1% dispersant, 1% hydroxyethyl cellulose, 0.07% germicide and for the rest water, where all percentages are weight percent. 7. Process for deforming ferrous or non-ferrous metals, characterized in that the molding dies are contacted with an effective amount of a molding mixture prepared by the reaction of adipic acid, about 1 to 35%, with alkali metal or alkaline earth metal hydroxide, about 0.5 to 19%, to form adipic acid salts, and further containing at least one conventional lubricant additive selected from the group consisting of organic thickeners, wetting agents, suspending agents, germicides, foam control agents, Ξ.Ρ.additives, pigments, corrosion inhibitors, dyes and perfumes, in amounts from about 0.1 to 10% and the remainder being water, all percentages being 15% by weight molds close under pressure, the molds open again and the moldings removed. 8. Process for deforming ferrous or non-ferrous metals, characterized in that the molds are contacted with an effective amount of a molding mixture, which is prepared by reacting 15% adipic acid with 8 , 1% sodium hydroxide, to form sodium adipate, which further contains 15% graphite, 1% dispersant, 1% hydroxyethyl cellulose, 0.07% germicide and the remainder being water, all percentages being percent by weight. molds under pressure, then open them again and remove the molding. Lubricant mixtures and methods for their use according to any one of the preceding claims, substantially as described in the foregoing description and / or illustrated by the examples. ! ji 800 0 5 69 V;