EP0334977B1 - Lubricant for metal deformation - Google Patents

Abstract

The invention relates to lubricants for the deformation of metallic materials which are suitable for cold-forming, in particular for drawing elongate formed material, and for hot-forming, in particular for drop-forging. The lubricant for cold-forming contains (A) 0.01 to 15% by mass of alkaline earth metal soaps, (B) 0.05 to 15% by mass of alkali metal borate or ammonium borate, (C) 0 to 14% by mass of alkali metal phosphate or ammonium phosphate, (D) 0 to 10% by mass of polymeric organic compounds and (E) 0.005 to 10% by mass of reaction products of components A to D, which have been formed in aqueous solution at a pH above 6.9 and at temperatures below 95 DEG C, the total of the proportions of components A to E being less than 35% by mass. The lubricant for hot-forming contains, in water, (A) 0.25 to 10% by mass of alkaline earth metal soaps, (B) 0.05 to 3% by mass of alkali metal borate or ammonium borate, (C) 0.05 to 8% by mass of alkali metal phosphate or ammonium phosphate, (D) 0.01 to 2% by mass of polymeric organic compounds and (E) 0.005 to 8% by mass of reaction products of components A to D, which have formed in aqueous solution at a pH above 6.9 and at temperatures below 80 DEG C, the total of the proportion of components A to E being less than 20% by mass. The lubricants are environmentally compatible, stable for a long time, highly effective and cheap.

Description

The invention relates to lubricants for hot forming, in particular for drop forging, and for cold forming, for example for cold rolling, cold upsetting, thread rolling, drawing sheet metal parts, calibrating sintered parts, stranding and bending, and in particular for drawing strand-shaped material, such as wire, Profiles and tubes.

The drop forging of metal forming material uses lubricants which serve to achieve a separating effect between the material to be formed and the tool, reduce tool wear and contribute to cooling the tool. The lubricants include known water-based.

One of these known lubricants contains adipic acid, alkali or alkaline earth hydroxide, conventional lubricant additives and, for certain applications, graphite (DE-A-30 13 842) in water. Hot forging converts the adipic acid with the alkali or alkaline earth hydroxide to form adipic acid salts, which are the main lubricant. This lubricant is with the Deficiency afflicted that it cannot be used without graphite additive for severe forming conditions in which the tools are subjected to particularly high loads and good lubrication is required since the adipic acid salts cannot be subjected to high loads due to their relatively low melting point. The graphite additive required for such conditions, on the other hand, leads to an increase in the cost of the lubricant, causes a deterioration in the separating effect of the lubricant between the tool and the material to be formed, and leads to environmental problems due to pollutant emissions and pollution of the workplace.

A large number of lubricants are known for the application of lubricant layers for cold forming, which are applied either directly to the metallic material or to previously applied lubricant carrier layers. also those that contain one or more lubricants in water.

One of these lubricants consists of an aqueous suspension containing calcium, magnesium, aluminum and / or barium stearate as a lubricant. In addition, this suspension also contains surface-active agents as dispersants, a lignin compound as a dispersion stabilizer and chlorinated paraffins and / or sulfurized fatty oil. This lubricant is used in such a way that the drawn material is immersed in heated lubricant, then dried and then shaped. These lubricant coatings do not have a very high dynamic viscosity, so that only relatively low forming speeds and degrees of forming can be achieved with materials that are difficult to form. As a result of the low heat resistance and the insufficient pressure absorption capacity during the Strain during the forming process, materials with a high specific heat of forming cannot be formed with this lubricant or only with increased technical effort. Also, several forming stages with only one application of lubricant can hardly be achieved due to the low dynamic viscosity and insufficient lubricant adhesion to the drawn material. Finally, it is disadvantageous that a wide variation in the dynamic viscosity of the lubricant is not possible. As a result, the surface condition of the drawn material cannot be set sufficiently material-specifically as a result of the shaping, and there is only insufficient adaptation of the lubricant to the load during the shaping.

An aqueous lubricant is also known which contains water-soluble alkali soaps and pyrophosphate (DE-A-1 594 512; US-A-3 313 729). Pyrophosphate cannot be used in conjunction with water-insoluble soaps, such as alkaline earth soaps, since the alkaline earth soaps react with the pyrophosphate and result in an unstable product that cannot be used as a lubricant. In this way, aqueous lubricants based on calcium stearate and soluble pyrophosphate solidify into a solid gel within hours to days, depending on the concentration.

From US-A-3 998 984 a lubricant carrier for lubricants for wire drawing is known, which is first applied to the wire material to be drawn, which is pulled through a bath with the actual lubricant for drawing. The composition for the base coating contains water-insoluble metal soaps, e.g. B. alkaline earth soaps, also sodium tetraborate and organic emulsifiers. According to one example, this composition can also contain sodium phosphate, sodium carbonate and sodium nitrite. The resulting base coating is less sensitive to softening due to air humidity due to the presence of the water-insoluble metal soap.

US-A-3 725 274 can also be found in lubricants for cold-forming metals which contain a meltable, water-soluble inorganic pigment, e.g. B. borax, a water-soluble metal soap, a hydrophilic colloid, e.g. B. from polyethylene glycol, polyvinyl alcohol, starch or cellulose derivatives, a finely divided water-insoluble thermoplastic polymer, for. As PVC, polyacrylonitrile or polyacrylates, also an organic phosphate and a water-insoluble soap, for. B. contain an alkaline earth soap.

Reaction products from alkaline earth soaps, borates, phosphates and organic compounds as additional components to lubricants were not known from the prior art explained above.

The invention has for its object to provide suitable for a high-performance hot and cold forming, environmentally friendly, long-term stable and cheap lubricants, which have good adhesiveness and a high pressure absorption capacity or a high and variable dynamic viscosity and thus the economical production of high quality Enable products with low tool wear.

The object is achieved according to claim 1. The dependent claims relate to preferred embodiments of the invention.

0,01 bis 15

Masse-% Erdalkaliseifen A,

0,05 bis 15

Masse-% Alkali- oder Ammoniumborat B,

0 bis 14

Masse-% Alkali- oder Ammoniumphosphat C
und

0 bis 10

Masse-% polymere organische Verbindungen D
sowie

0,005 bis 10

Masse-% in wässeriger Lösung bei einem pH-Wert über 6,9 und bei Temperaturen unter 95 °C entstandene Reaktionsprodukte E der Komponenten A bis D,

wobei die Summe der Anteile der Komponenten A bis E kleiner als 35 Masse-% ist.The invention Lubricants for the shaping of metallic materials consist of water and the following components dispersed or dissolved in it:

0.01 to 15

Mass% alkaline earth soaps A,

0.05 to 15

Mass% alkali or ammonium borate B,

0 to 14

% By mass of alkali or ammonium phosphate C
and

0 to 10

% By mass of polymeric organic compounds D
such as

0.005 to 10

% By mass in aqueous solution at a pH above 6.9 and reaction products E of components A to D formed at temperatures below 95 ° C.,

the sum of the proportions of components A to E being less than 35% by mass.

The optional components C and D are accordingly essential starting materials for the reaction products E.

These lubricants are particularly suitable for cold forming metallic materials.

Preferably in the above-defined lubricants according to the invention, which are particularly suitable for cold forming in this composition, 2 to 8% by mass of alkaline earth soap A, 0.2 to 1.5% by weight of alkali metal or ammonium borate B, 3 to 6% by weight % Alkali or ammonium phosphate C and 0.1 to 0.8% by mass of polymeric organic compounds.

According to a further preferred embodiment of these lubricants, 2 to 8 mass% of alkaline earth soap A, 1.2 to 8 mass% of alkali or ammonium borate B, 0 to 0.5 mass% of alkali or ammonium phosphate C and 0 to 2.5 % By mass of polymeric organic compounds D.

• (A) 0,25 bis 10 Masse-% Erdalkaliseifen,
• (B) 0,05 bis 3 Masse-% Alkali- oder Ammoniumborat,
• (C) 0,05 bis 8 Masse-% Alkali- oder Ammoniumphosphat,
• (D) 0,01 bis 2 Masse-% polymere organische Verbindungen und
• (E) 0,005 bis 8 Masse-% in wässeriger Lösung bei einem pH-Wert über 6,9 und bei Temperaturen unter 80 °C entstandene Reaktionsprodukte der Komponenten A bis D,

wobei die Summe der Anteile der Komponenten A bis E kleiner als 20 Masse-% ist.Lubricants according to the invention, especially suitable for the hot forming of metallic materials, have the following composition of the lubricant components:

• (A) 0.25 to 10% by mass of alkaline earth soaps,
• (B) 0.05 to 3% by mass of alkali or ammonium borate,
• (C) 0.05 to 8% by mass of alkali or ammonium phosphate,
• (D) 0.01 to 2% by mass of polymeric organic compounds and
• (E) 0.005 to 8% by mass in aqueous solution at a pH above 6.9 and reaction products of components A to D formed at temperatures below 80 ° C.,

the sum of the proportions of components A to E being less than 20% by mass.

This hot-working lubricant preferably contains 0.5 to 6% by mass of alkaline earth soap A, 0.5 to 3% by weight of alkali or ammonium borate B, 1 to 7% by weight of alkali or ammonium phosphate C and 0.15 to 0 , 5% by mass contain polymeric organic compounds.

Lime soaps with an increased stearate content of up to 65% by mass can be used as alkaline earth soaps A and sodium tetra- or sodium metaborate as alkali borate B.

According to the invention, sodium polyphosphate, in particular Graham's salt, is preferably used as alkali metal phosphate C.

Suitable polymeric organic compounds D are in particular polyvinyl alcohol, oxidatively modified polyvinyl alcohol, gelatinized starch and / or nonylphenol-polyethylene oxide adducts.

• a) Produkte von Reaktionen der Erdalkaliseifen A mit dem Alkali- oder Ammoniumborat B in teilweiser nichtstöchiometrischer Zusammensetzung,
• b) Produkte einer teilweisen oder vollständigen Hydrolyse von Natriumpolyphosphat,
• c) Produkte von Reaktionen der Erdalkaliseifen A mit den Produkten b),
• d) Produkte von Reaktionen der Produkte b) mit dem Alkali-  oder Ammoniumborat B,
• e) Produkte von Reaktionen der Erdalkaliseifen A mit den Produkten d),
• f) Produkte von Reaktionen der Produkte b) mit den polymeren organischen Verbindungen D,
• g) Produkte von Reaktionen des Alkali- oder Ammoniumborats B mit den polymeren organischen Verbindungen D
  und
• h) Produkte von Reaktionen der Produkte b) mit den Produkten g).

The reaction products E contained are in particular

• a) products of reactions of the alkaline earth soaps A with the alkali metal or ammonium borate B in partial non-stoichiometric composition,
• b) products of a partial or complete hydrolysis of sodium polyphosphate,
• c) products of reactions of the alkaline earth soaps A with the products b),
• d) products of reactions of products b) with the alkali metal or ammonium borate B,
• e) products of reactions of the alkaline earth soaps A with the products d),
• f) products of reactions of products b) with the polymeric organic compounds D,
• g) products of reactions of alkali or ammonium borate B with the polymeric organic compounds D
  and
• h) products of reactions of the products b) with the products g).

With the lubricants according to the invention, considerable advantages are achieved in hot forming compared to the previously customary procedure in which a graphite dispersion is used. As a result of the elimination of the graphite contamination, the working conditions and environmental protection are significantly improved. Thanks to the very good lubricating properties, the tool life is also significantly longer. The very good forming properties of the lubricants are surprisingly probably due to a partial thermal decomposition of the components contained in the lubricants on the tool with the formation of acidic reactive decomposition products, which apparently have a favorable combination of lubricating and blowing action in the active joint between the workpiece and Tool, combined with a favorable thermal insulation.

The lubricants according to the invention can be produced with cheap raw materials and thus have a favorable effect on the economy of the forming of metallic products. It is also advantageous that the lubricants do not tend to settle or gel, even after prolonged storage.

For cold forming, adhesive and high-performance lubricant layers can be produced with the lubricants according to the invention. This reduces tool wear and improves product quality, as well as high degrees of forming and speeds will be realized. In addition, intermediate coatings between individual forming stages can be largely avoided.

The invention is explained in more detail below using an exemplary embodiment.

example

1,6

Masse-% Calciumstearat,

0,16

Masse-% Natriumtetraborat,

1,3

Masse-% Natriumpolyphosphat,

0,05

Masse-% Alkylphenolpolyglycolether
und

0,3

Masse-% in wässeriger Lösung bei einem pH-Wert von 8 und einer Temperatur von 25 °C entstandene Reaktionsprodukte der vorgenannten Komponenten.

The example concerns a lubricant for drop forging. The lubricant contains in water

1.6

Mass% calcium stearate,

0.16

Mass% sodium tetraborate,

1.3

Mass% sodium polyphosphate,

0.05

% By mass of alkylphenol polyglycol ether
and

0.3

% By mass in aqueous solution at a pH of 8 and a temperature of 25 ° C. reaction products of the aforementioned components.

This lubricant is used to drop-forged St 52 ingots heated to around 1250 ° C. The lubricant is applied to the work surfaces of the tool. The application is carried out with the help of spray nozzles and in the form of an air-lubricant jet. The amount of lubricant sprayed or the air-lubricant ratio can be varied to influence the temperature of the tool. The spray pressure is advantageously chosen so high that any scale particles on the tool are removed with the spray jet. Before the first application of the lubricant and also after a series of forming processes, the tool can be treated with a lubricant carrier be subjected, for example, by immersion in a borax or phosphate solution.

Claims (9)

1. Lubricants that consist of water and the following components dispersed or dissolved therein:
   0.01 to 15 % by weight of alkaline earth soaps A,
   0.05 to 15 % by weight of alkali or ammonium borate B,
   0 to 14 % by weight of alkali or ammonium phosphate C
   and
   0 to 10 % by weight of polymeric organic compounds D
   as well as
   0.005 to 10 % by weight of reaction products E of components A to D produced in aqueous solution at a pH value above 6.9 and at temperatures below 95 °C,
   the sum of the proportions of components A to E being less than 35 % by weight, for the forming of metallic materials.
2. Lubricants according to Claim 1, characterized in that they contain
   0.25 to 10 % by weight of alkaline earth soaps A,
   0.05 to 3 % by weight of alkali or ammonium borate B,
   0.05 to 8 % by weight of alkali or ammonium phosphate C,
   0.01 to 2 % by weight of polymeric organic compounds D
   and
   0.005 to 8 % by weight of reaction products E of components A to D produced in aqueous solution at a pH value above 6.9 and at temperatures below 80 °C,
   the sum of the proportions of components A to E being less than 20 % by weight, for the hot forming of metallic materials.
3. Lubricants according to Claim 2, characterized in that they contain 0.5 to 6 % by weight of alkaline earth soaps A, 0.5 to 3 % by weight of alkali or ammonium borate B, 1 to 7 % by weight of alkali or ammonium phosphate C and 0.15 to 0.5 % by weight of polymeric organic compounds D.
4. Lubricants according to Claim 1, characterized in that they contain 2 to 8 % by weight of alkaline earth soaps A, 0.2 to 1.5 % by weight of alkali or ammonium borate B, 3 to 6 % by weight of alkali or ammonium phosphate C and 0.1 to 0.8 % by weight of polymeric organic compounds D.
5. Lubricants according to Claim 1, characterized in that they contain 2 to 8 % by weight of alkaline earth soaps A, 1.2 to 8 % by weight of alkali or ammonium borate B, 0 to 0.5 % by weight of alkali or ammonium phosphate C and 0 to 2.5 % by weight of polymeric organic compounds D.
6. Lubricants according to one of Claims 1 to 5, characterized in that they contain calcium soaps with an elevated stearate content of up to 65 % by weight as alkaline earth soaps A.
7. Lubricants according to one of Claims 1 to 6, characterized in that they contain sodium tetraborate or sodium metaborate as alkali borate B.
8. Lubricants according to one of Claims 1 to 7, characterized in that they contain sodium polyphosphate, preferably Graham's salt, as alkali phosphate C.
9. Lubricants according to one of Claims 1 to 8, characterized in that they contain polyvinyl alcohol, oxidatively modified polyvinyl alcohol, gelatinized starch and/or nonylphenol-poly(ethylene oxide) adducts as polymeric organic compounds D.