DE1594502A1 - lubricant - Google Patents

Description

METALLGESELLSCHAFT Frankfurt (Main), August 2, 1965

STOCK PARTNERSHIP DrBr / BK

Frankfurt (Main)

prov. Mr. 4665 1594502

lubricant

It is common practice to prepare metals for cold working by applying an emic coating. Before deformation the metal surface provided with the chemical coating is often treated with a lubricant, for example in a hot aqueous soap solution. There is a heat between the hot soap solution and the one before applied chemical coating, for example a phosphate coating, instead, and it forms a metal soap that firmly with the Ph :. sphat coating and thereby with the metal surface itself is connected. The coating is essentially insoluble in water and provides a good release layer during de »subsequent deformation treatments. After deformation In many cases, the workpiece is subjected to further treatments for which the presence of a pure surface is required. However, it often causes considerable difficulties after the deformation on the To remove any adherent film on the surface. Avoiding this disadvantage is therefore very desirable.

When various soap-type lubricants are used, particularly those containing substantial amounts of inorganic pigments such as borax , it has also been found that not only the soap-type lubricants

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Lubricant must be kept at relatively high temperatures, for example above about 82 ^° C., in order to keep it in a sufficiently liquid state for use on the metal surfaces provided with the chemical coating, but that in the case of roller application processes, the rollers themselves are often heated must to prevent solidification of the lubricant on them during application. It is therefore also desirable that the soap-containing lubricant is so composed that it has sufficient flowability even at lower temperatures, e.g. B. 65 ⁰ C or lower, so that it can be used without heating the rollers.

It has now been found that these improvements are obtained with a lubricant which contains fatty acid soap together with alkali pyrophosphate. Preferably, the lubricant contains a fatty acid soap concentrate in amounts of from 15 to 97 wt. I »and Alkalipyr opho sphat in amounts of 3 to 75 #

Alkali pyrophosphates are taken to mean the pyrophosphates of lithium, sodium, potassium, cesium and rubidium. Particularly good results have been obtained using tetrapotassium pyrophophate (TKPP). It is therefore preferred.

The inventive lubricants can use the soap as contain such. However, components that react with one another to form soap can also be used, for example

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Fatty acids, fats or oils on the one hand and alkali on the other hand, such as for example alkali hydroxide or alkali carbonate can be added. Particularly suitable fatty acid soaps are those which contain from about 8 to about 22 carbon atoms, with a content from 12 to about 18 carbon atoms is preferred.

In addition to the tetrapotassium pyrophosphate and the soap you can the lubricants according to the invention also contain various other additives, depending on their particular properties the lubricants are desired in the particular case. For example, various so-called pigments, namely both fusible and infusible can be added. In addition, organic resinous or polymeric binders can be used resin acids and / or various resin soaps are added to the lubricant. In addition, for example, corrosion inhibitors, Dyes, fragrances and the like Lubricants can be added if desired.

Among the pigments added to the lubricant according to the invention include, for example, antimony oxide, antimony sulfide, arsenic oxide, arsenic sulfide, barium pyrophoephate, wispite sulfide, Boric anhydride, calcium tetraborate, calcium carbonate, Cadmium pyrophosphate, cobalt sulfide, chromium fluoride, copper sulfide, Ferrous sulfide, ferrophosphate, lead borate, lead chromate, lead molybdate, Lead oxide, lead phosphate, lead metasilicate, lead sulfide, manganese pyrophosphate, Manganese borate, mercury sulfide, mercury chloride,

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Molybdenum oxide, nickel sulfide, molybdenum sulfide, sodium tetraborate (Borax), vanadium pentoxide, zinc borate, zinc phosphate, clays, such as ζ. Β. Diatomaceous earth, puller earth and the like. These and similar pigments can be added to the lubricant in addition to alkali pyrophosphate be added or replace part of it. When pigments are added to the lubricant, amounts are about 0.1 to about 80 wt. $ is useful. Preferably amounts from about 3 to about $ 75 are used.

Examples of binders that can be used are polymers, acrylic esters, z. B. polymethacrylates} alkyd resins, such as. B. those of the glycerol-phthalic anhydride type} Cellulose acetate} cellulose nitrate} coumarone indene polymers} styrene polymers {chlorinated diphenyl} chlorinated rubber} ethylene polysulphide polymers} chlorinated Paraffins? Neoprene rubber; Vinyl chloride; Vinyl acetate, melmain polymers j Urea-aldehyde polymers} casein-iOrmaldehyde polymers} Phneol-Formaldehyde Polymers Starch, Sodium Naphthenate; Amber} Asphalt, bitumen} gilsonite} dextrin} gelatin} gum arabic and the like. When using such binders amounts ranging from about 0.1 to about 25 percent by weight are suitable. Preferably the amounts are from about 1 to about 15 ^.

The resin acids can be in the form of commercially available gum or wood resin, tall oil. You can also use tall oil residue be extracted. The term "resin acids" is therefore understood in the customary broad sense and also includes special acids such as abietic acid, beoabietin

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acid, pimaric acid, levopimaric acid, dextropimaric acid, isodextropimaric acid and mixtures thereof, and resin soaps made from these acids. If resin soaps and / or resin acids are added to the lubricant quantities are used in the range from 0.1 $ to 30 $> appropriate. Preferably, amounts from about 0.5 "to about 10.0 9 ^ are used.

Suitable corrosion inhibitors are, for example, alkali nitrates, Alkali nitrites and the like. They are conveniently used in amounts of about 0.1 to about $ 5.0, preferably in amounts of about 0.1 to about 3.0 ^ added, dyes, such as Bismark brown and the like, as well as fragrances or other substances that give the lubricant a pleasant smell, such as pine oil and the like, can be added to the lubricant be added. They are used in amounts sufficient to give the agent the desired color or color to give the desired smell.

In addition to the above additives, the soap and tetrapotassium pyrophosphate-containing concentrates can also contain water , the amount of which depends on the physical form desired. Water can be used in amounts up to about 80% by weight of the total composition. Preferably

water

however, 15 to about 75 wt. $ are added. Which physical form or consistency of the soaking agent concentrate? is desired, of course, depends on the way in which the agent is to be treated, packaged and transported. To the-

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accordingly, the amount of water added to the mixture can be will be changed over a wide range. In some cases the water content can even exceed 80% by weight. Even when water is used in amounts of 75% by weight, the concentration is still undesirably high for various Applications on metallic surfaces. In most cases, therefore, the concentrate will be substantial even if it is already substantial Amount of water contains further diluted with water before it is used. Means used contain the lubricant concentrate appropriately in amounts of about .12 g / l to 480 g / l solution. Preferred salary is about 60 to 240 g / l.

A solution containing about 12 to 480 g / l concentrate has a Babcock number in the range from about 0.4 to about 125 and a titration number in the range from about 3 to about 18.5. The Babcock number is determined in the following way: 50 ml of the lubricant solution intended for use are placed in a 100 ml volumetric flask (cassia bottle) with a graduated neck. Add 20 ml of 50% sulfuric acid and mix thoroughly. The flask is then placed in a water bath at a temperature between 82 ⁰ C and the boiling point, and immediately thereafter plenty of hot water is added to the flask to bring the level of the solution in legs graduated sharks. When the oily skin has severed sharply, which usually takes about half an hour

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the pall is, becomes the difference between the lower mirror and the frequent level of the oil column in the neck of the bottle. This value is the Babcock number. The titration number is determined as follows: 50 ml of the heated lubricant solution are placed in a beaker with about 120 ml of hot water. The solution is then titrated with a 0.88 normal sulfuric acid. The titration number is the number of ml of sulfuric acid that are consumed to make up the lubricant solution titrate to the bromocresol green endpoint.

The lubricant solutions can be applied in any desired manner to the metal surfaces to be deformed, for example by dipping, flooding, spraying or rolling on. In these applications, the temperature of the lubricant can be varied within wide limits, from room temperature up to about 100.degree. In a dipping process, in general, higher temperatures of the lubricant are desired, for example 60 to 100 ⁰ C. When rolling other hand, can lower temperatures, eg. B. room temperature to 60 ⁰ O, can be used. When applying the lubricant by roller application at room temperature , it may be desirable to apply the lubricant as a concentrate without further dilution. The application to the rollers is then expediently carried out by compressed air, a piston pump or a rotary pump.

The lubricant according to the invention is provided with a chemical coating on metal surfaces before they are deformed

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■ ™ O · "·

have been applied. Suitable chemical coatings are phosphate coatings, oxide coatings, oxalate coatings, sulfide coatings and the same. When the desired amount of lubricant is applied to the surface, the lubricant coating becomes dried. The workpiece is then drawn or otherwise cold-formed.

Before applying the chemical coating to the metal surface a cleaning or pickling stage is usually used. A rinse is also carried out to remove the Remove cleaning or pickling solution from the surface. In many cases there is between the application of the chemical Coating and the application of the lubricant coating one further rinsing is carried out to remove coating material that has not reacted from the surface. The latter The rinse can be a water rinse, but rinses with alkaline or neutralizing solutions are often used carried out.

It was found that workpieces produced in the specified manner and using the lubricant according to the invention prepared for deformation, after deformation it is considerably easier to remove the remaining lubricant and coating film could be cleaned in comparison to other workpieces where the well-known soap-based lubricants had been applied to the chemical coating. In addition, it was found that the lubricant according to the invention

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medium on the surfaces to be deformed at lower Temperatures can be used than previously with the known soap-containing lubricants, especially those the pigments, such as B. borax included, was possible. In many cases it has also been found that the inventive Lubricant coatings have a greater hardness and thus greater protection against damage during mechanical Communicate treatment of the workpieces. It has also often been found that the lubricants according to the invention have an increased effect Have corrosion resistance and that they do not tend to accumulate to any appreciable extent on the rolls, if roll-on processes are used for application. In all cases it was found that the deformability of the metal surfaces, which were coated with the lubricant according to the invention was at least equal to, if not greater than, them was obtained with the known lubricants.

Example I.

A lubricant concentrate was prepared from 75% by weight of a sodium tallow soap and 25% by weight of anhydrous lethal potassium pyrophosphate. An aqueous lubricant solution containing 90 g / l of the solid concentrate was prepared from this concentrate. Stainless steel plates were immersed for 1 minute in this solution at a lubricant! Temperature of about 80 ⁰ O. After being removed from the lubricant bath, the panels were dried. There was an im on the metal sheets

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an essentially uniform coating of gray to whitish color.

Example II

0.2 g Bismarck brown was dissolved in 740 g water. 84.5 g of potassium hydroxide were added to this solution. The solution was heated to about 95 ⁰ O. To the heated solution were added 18 g of sodium nitrite, 27 g of borax (decahydrate) and 523 g of anhydrous tetrapotassium pyrophosphate. 454 g of a mixture of stearic acid and palmitic acid were melted and heated to about 95 ⁰ C. 4.5 g of pine oil were added to this melt. The mixture of fatty acid and pine oil was then added to the previously prepared aqueous solution with stirring. The mixture obtained was held for about 2Ό minutes to about 95 ⁰ C, the solution was stirred to cause an intensive mixing and reaction. The solution was then cooled to room temperature while stirring. An aqueous lubricant solution containing 180 g / l concentrate was then prepared from the concentrate. This solution was maintained at about 75 ⁰ C with the aid of rolling devices on automobile bumpers blanks, which had been previously coated with a conventional zinc phosphate coating applied. After the lubricant had been applied, the film obtained was dried and the blanks coated in this way were subjected to conventional cold forming. A total of about 1000 such bumper blanks were made in this way

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treated. In each case, excellent bumpers were obtained.

Example III

A lubricant concentrate was prepared by mixing 46.7 i ° a Natriumtalgseife, 20 $ Borax (decahydrate) and 33 »$ 3 of anhydrous tetrapotassium pyrophosphate. An aqueous lubricant solution containing 120 g / l concentrate was prepared from this concentrate. The solution was applied at room temperature by roller application to steel surfaces which had been provided with an oxalate coating. A piston pump was used to apply the lubricant to the rollers. After the applied lubricant coating had dried, substantially uniform lubricant coatings were obtained on the metal surfaces which were suitable for protecting the metal during relatively severe drawing treatments.

Example IV

3.8 l of an aqueous soap solution containing 227 g of sodium tallow soap were prepared. The solution was brought to a temperature of 80 ⁰ C. Steel panels which had previously been provided with a conventional zinc phosphate coating were immersed in this soap solution and left in it for 1 minute. The metal sheets were removed from the bath and dried in the oven ^{at about 110 ° C. for 15 minutes.} The solutions then became different

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Amounts of tetrapotassium pyrophosphate added. Steel sheets with were provided with a zinc phosphate coating, were then immersed in this soap solution and then in the above manner in Oven dried. All panels were weighed "before the soap-containing lubricant was applied and then re-weighed reweighed the drying of the lubricant. The weight gain was the amount of soap lubricant that was on the sheets had been deposited.

After the second weighing, the metal sheets were cleaned by holding them in overflowing hot water for 30 seconds at a temperature of approximately 71 ^° C. The panels were then quickly immersed in and immediately removed from cold water, and then blown dry with air. The sheets were then weighed again. The weight loss was the amount of coating that was removed by cleaning the panels. To determine the percentage cleaning achieved on the panels, the weight of the coating removed by cleaning was divided by the weight of the lubricant applied to the panels and the quotient was multiplied by 100. If the value obtained is greater than 100, it indicates that, in addition to the soap lubricant, some of the previously applied phosphate chemical coating has also apparently been removed. Using the procedure outlined above, the following results were obtained:

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- 13 8AD Of = MGIlMAL

Follow the “·, medium” “β coating

TKPP in the lubricant. _

0 100

1 '101 4 109

10 123

25 147

50 132

100 114

Example V

The working method according to example IT was repeated with the change, that as a soap solution, which was used to coat the metal sheets and the tetrapotassium pyrophosphate was added, 3 »8 Solution containing 113.5 g borax and 113.5 g sodium tallow soap, were used »The following results were obtained:

fo TKPP in the lubricant f> the coating when cleaning
removed 0 94 10 102 25th 132 50 126 100 111

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-H- Example YI

Steel bars coated with a conventional zinc phosphate coating were treated as described in Example IV. The bars were then passed through a test device in which the stress on the workpieces during the heaviest drawing operations is simulated. The bars were then cleaned in the manner indicated in Example IV. The weight of the coating removed was determined. The following results were obtained:

"jo TKPP in the lubricant coating removed by cleaning (in mg / m ² )

0 572

33. 3212

66 1100

100 3817

From the results of Examples IV to VI it can be seen that when using tetrapotassium pyrophosphate containing Lubricants the cleaning of the metal surfaces is considerably facilitated and that "this improvement is also obtained after previous deformation treatment

The experiments of the above examples were repeated using lubricants containing tetrasodium pyrophoephate and Resin acids contained, and which were applied to oxide and sulfide coatings. Similar results were obtained.

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Claims (4)

- 15 claims 1. Soapy lubricant to facilitate cold working of metallic workpieces provided with a chemical coating, characterized in that it is alkali metal pyrophosphate contains. 2 «Lubricant according to claim 1, characterized in that it contains 15 to 97 percent by weight fatty acid soap, 3 to 75 percent by weight alkali metal pyrophosphate and optionally water in amounts up to 80% by weight contains. 3. Lubricant according to claim 1 and 2, characterized in that it contains tetrapotassium pyrophosphate. 4. Lubricant according to claim 1 to 3, characterized in that the fatty acid soap in situ in the lubricant by Reaction of alkali hydroxide and fatty acids is formed. 009819/1554 - "* BATH ORIGINAL