EP0334977A1 - 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 die forging, as well as for cold forming, for example for cold rolling, cold heading, thread rolling, drawing sheet metal parts, calibrating sintered parts, stranding and bending and in particular for the drawing of stranded Umformgut, such as wire, Profiles and pipes.

When forging metal forming material, lubricants are used which serve to achieve a separating effect between the material to be formed and the tool, reduce tool wear and contribute to the cooling of the tool. As a lubricant, i.a. such known on water basis.

One of these known lubricants contains in water adipic acid, alkali or alkaline earth metal hydroxide, conventional lubricant additives and graphite for certain applications (DE-A-30 13 842). In warm forging reaction of adipic acid with the alkali or alkaline earth metal hydroxide to adipic acid salts, which are the main lubricant. This lubricant is with the Lack lacks that it can not be used without graphite addition for severe forming conditions in which the tools are particularly highly stressed and good lubrication is required because the adipic acid salts are not highly resilient due to their relatively low melting point. On the other hand, the graphite additive necessary for such conditions leads to an increase in the cost of the lubricant, causes a deterioration of the release effect of the lubricant between the tool and Umformgut and leads to environmental problems due to pollutant emissions and pollution of the workplace.

For the application of cold-working lubricant layers applied either directly to the metallic material or to previously applied lubricant carrier layers, a variety of lubricants are known, i.a. also those containing 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, surfactants are also present in this suspension as dispersants, a lignin compound as a dispersion stabilizer and chloroparaffins and / or sulfurized fatty oil. The application of this lubricant is carried out in such a way that the drawn material dipped in heated lubricant, then dried and then transformed. These lubricant coatings do not have a very high dynamic viscosity, so that only relatively low deformation rates and deformation rates can be realized in difficult to convert materials. Due to the low heat resistance and the low pressure absorption during the Strain during forming can not be converted materials with large specific forming heat or only with increased technical effort with this lubricant. Also, several forming stages are difficult to achieve with only one lubricant application due to the low dynamic viscosity and insufficient adhesion of the lubricant on the stock. The disadvantage is finally that a wide variation of the dynamic viscosity of the lubricant is not possible. As a result, the surface state of the drawn material as a result of the transformation can not be set sufficiently specific material and there is only an insufficient adjustment of the lubricant to the load during the forming given.

An aqueous lubricant containing water-soluble alkali soaps and pyrophosphate is also known (DE-A-1 594 502, US-A-3 313 728). In conjunction with water-insoluble soaps, e.g. Alkaline earth soap, the use of pyrophosphate is not possible because the alkaline earth metal soaps react with the pyrophosphate and an unstable, as a lubricant unusable product results. Thus, aqueous lubricants based on calcium stearate and soluble pyrophosphate solidify depending on the concentration within hours to days to a solid gel.

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

The problem is solved according to claim 1. The dependent claims relate to preferred embodiments of the invention.

• (A) 0,01 bis 15 Masse-% Erdalkaliseifen,
• (B) 0,05 bis 15 Masse-% Alkali- oder Ammoniumborat,
• (C) 0 bis 14 Masse-% Alkali- oder Ammoniumphosphat,
• (D) 0 bis 10 Masse-% polymere organische Verbindungen und
• (E) 0,005 bis 10 Masse-% in wässeriger Lösung bei einem pH-Wert über 6,9 und bei Temperaturen unter 95 °C entstandene Reaktionsprodukte der Kompo­nenten A bis D

enthalten sind, wobei die Summe der Anteile der Kompo­nenten A bis E kleiner als 35 Masse-% ist.The lubricant according to the invention for the transformation of metallic materials, in which lubricant components are dispersed and dissolved in water, is characterized in that

• (A) 0.01 to 15% by mass alkaline earth soap,
• (B) 0.05 to 15% by mass of alkali or ammonium borate,
• (C) 0 to 14% by mass of alkali or ammonium phosphate,
• (D) 0 to 10% by mass of polymeric organic compounds and
• (E) 0.005 to 10% by mass in aqueous solution at a pH above 6.9 and at temperatures below 95 ° C resulting reaction products of components A to D.

are included, wherein the sum of the proportions of the components A to E is less than 35% by mass.

This lubricant is particularly suitable for the cold forming of metallic materials.

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

According to a further preferred embodiment of this lubricant are 2 to 8 mass% Erdalkaliseifen A, 1.2 to 8 mass% alkali or ammonium borate B, 0 to 0.5 mass% of alkali metal or ammonium phosphate C and 0 to 2.5 Mass% polymeric organic compounds D included.

• (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

enthalten sind, wobei die Summe der Anteile der Komponen­ten A bis E kleiner als 20 Masse-% ist.An inventive, especially for the hot forming of metallic materials suitable lubricant in which lubricant components are dispersed and dissolved in water, characterized in that

• (A) 0.25 to 10 mass% 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 at temperatures below 80 ° C resulting reaction products of components A to D.

are included, wherein the sum of the proportions of the components A to E is less than 20 mass%.

Preferably, in this lubricant for hot forming 0.5 to 6 mass% alkaline earth metal soaps A, 0.5 to 3 mass% alkali or ammonium borate B, 1 to 7 mass% alkali or ammonium phosphate C and 0.15 to 0 , 5 mass% contain polymeric organic compounds.

According to the invention, alkaline earth soap A can be lime soaps having an increased stearate content of up to 65% by mass and sodium borate or sodium metaborate as alkali borate B.

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

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 metal soaps A with the alkali or ammonium borate B in a partial non-stoichiometric composition,
• b) products of partial or complete hydrolysis of sodium polyphosphate,
• c) products of reactions of alkaline-earth soaps A with products b),
• d) products of reactions of the products b) with the alkali or ammonium borate B,
• e) products of reactions of alkaline-earth soaps A with products d),
• f) products of reactions of the products b) with the polymeric organic compounds D,
• g) products of reactions of the 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 lubricant according to the invention, considerable advantages are achieved in the hot forming compared to the previously customary procedure in which working with a graphite dispersion. Thus, as a result of the elimination of the graphite contamination, the working conditions and environmental protection are substantially improved. Due to the very good lubricating properties also the tool life is much higher. The very good forming properties of the lubricant arise in a surprising manner probably by taking place on the tool partial thermal decomposition of the components contained in the lubricant to form acidic reactive decomposition products, apparently a favorable combination of lubricating and blowing action in the Wirkfuge between the workpiece and tool , combined with a favorable thermal insulation result.

The lubricants according to the invention can be produced with inexpensive raw materials and thus have a favorable effect on the cost-effectiveness of forming metallic products. It is also advantageous that the lubricants are prone to settling or gel formation even after prolonged storage.

For cold forming, adhesive-resistant and high-performance lubricant layers can be produced with the lubricants according to the invention. This reduces tool wear, improves product quality and allows high degrees of reshaping and forming speeds will be realized. Furthermore, intermediate coatings between individual forming stages can be largely eliminated.

The invention will be explained in more detail below with reference to exemplary embodiments.

example 1

The example concerns a lubricant for die forging. The lubricant contains in water
1.6% by mass of calcium stearate,
0.16% by mass of sodium tetraborate,
1.3% by mass of sodium polyphosphate,
0.05% by mass of alkylphenol polyglycol ether and
0.3 mass% in aqueous solution at a pH of 8 and a temperature of 25 ° C resulting reaction products of the aforementioned components.

This lubricant forged to about 1250 ° C St 52 ingots forged. Here, the lubricant is applied to the working surfaces of the tool. The application is carried out by means of spray nozzles and in the form of an air-lubricant jet. It can be varied to influence the temperature of the tool, the sprayed amount of lubricant or the air-lubricant ratio. Advantageously, the spray pressure is chosen so high that any spray particles on the tool are removed with the spray. Before the lubricant is applied for the first time, and also after a number of forming operations, the tool can be treated with a lubricant carrier be subjected, for example by immersion in a borax or phosphate solution.

Example 2

The example concerns a lubricant for wire drawing. The lubricant contains in water
4.5% by mass of calcium stearate,
0.4% by mass of sodium tetraborate,
3.8% by mass of sodium polyphosphate and
0.5 mass% in aqueous solution at a pH of 8 and a temperature of 35 ° C resulting reaction products of the aforementioned components.

This lubricant is coated in a 3.5 mm thick M7 grade steel wire in a continuous process. After coating, the wire is dried and drawn to 1.2 mm in 7 passes without an intermediate lubricant coating.

Example 3

The example concerns a lubricant for wire drawing. The lubricant contains in water
5% by mass of calcium stearate,
2.5% by mass of sodium tetraborate,
1.5% by weight of polyvinyl alcohol and
0.6 mass% in aqueous solution at a pH of 8.5 and a temperature of 45 ° C resulting reaction products of the aforementioned components.

This lubricant is used to draw 1.2 mm thick C 15 Q Grade C 15 Q steel wire in a wet drawing machine in 15 passes at 0.3 mm.

Claims (9)

1. A lubricant for the forming of metallic materials, wherein the lubricant components are dispersed in water and dissolved, characterized in that
(A) 0.01 to 15% by mass alkaline earth soap,
(B) 0.05 to 15% by mass of alkali or ammonium borate,
(C) 0 to 14% by mass of alkali or ammonium phosphate,
(D) 0 to 10% by mass of polymeric organic compounds and
(E) 0.005 to 10% by mass in aqueous solution at a pH above 6.9 and at temperatures below 95 ° C resulting reaction products of components A to D.
are included, wherein the sum of the proportions of the components A to E is less than 35% by mass. 2. A lubricant according to claim 1 for the hot forming of metallic materials, wherein the lubricant components are dispersed in water and dissolved, characterized in that (A) 0.25 to 10 mass% 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 at temperatures below 80 ° C resulting reaction products of components A to D.
are included, wherein the sum of the proportions of the components A to E is less than 20 mass%. 3. A lubricant according to claim 2, characterized in that 0.5 to 6 mass% alkaline earth metal soaps A, 0.5 to 3 mass% alkali or ammonium borate B, 1 to 7 mass% alkali or ammonium phosphate C and 0, 15 to 0.5 mass% of polymeric organic compounds are contained. 4. A lubricant according to claim 1, characterized in that 2 to 8% by mass of alkaline earth metal soaps A, 0.2 to 1.5% by mass of alkali metal or ammonium borate B, 3 to 6% by mass of alkali or ammonium phosphate C and 0, 1 to 0.8% by mass of polymeric organic compounds D are contained. 5. A lubricant according to claim 1, characterized in that 2 to 8 mass% alkaline earth metal soaps A, 1.2 to 8 mass% alkali or ammonium borate B, 0 to 0.5 mass% of alkali metal or ammonium phosphate C and 0 to 2.5% by mass of polymeric organic compounds D are contained. 6. Lubricant according to one of claims 1 to 5, characterized in that contained as alkaline earth metal soaps A lime soaps having an increased stearate content of up to 65% by mass. 7. A lubricant according to any one of claims 1 to 6, characterized in that as alkali borate B sodium tetra- or sodium metaborate is included. 8. A lubricant according to any one of claims 1 to 7, characterized in that the alkali phosphate C is sodium polyphosphate, preferably Graham's salt. 9. A lubricant according to any one of claims 1 to 8, characterized in that as polymeric organic compounds D polyvinyl alcohol, oxidatively modified polyvinyl alcohol, gelatinized starch and / or nonylphenol-polyethylene oxide adducts are included.