DE3438525A1 - METHOD FOR EASIER COLD DEFORMING - Google Patents

Description

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NIHON PARKERIZING CO., LTD. October 15, 1984

Tokyo 103, Japan DROZ / LWÜ / 1868P

Prov. No. 9149 M.

Process to facilitate cold deformation

The invention relates to a method for facilitating the cold working of metals by applying a film of lubricant based on resin.

In order to be able to work in the cold forming of metals, e.g. by pressing, rolling, wire or pipe drawing and forging, friction and Lubricants are applied to prevent wear and tear on metal and tools. With relatively little The degree of deformation is found in lubricants that have high-pressure additives or viscosity regulators are added. With a high degree of deformation, the formation of a coating is common, for example in the case of normal steel by means of phosphating and soaping, in the case of stainless steel by means of oxalate treatment and Soap up. Requires pretreatment by forming a coating a heating of the treatment solution and, as a rule, a cleaning of the rinsing water produced, possibly also a costly removal of used treatment baths. The removal of the coating remaining after the deformation also often causes additional difficulties.

More recently, for energy saving, environmental protection, To increase productivity, etc., a simplification and shortening of the pretreatment process is required. In this The pre-treatment to facilitate the cold forming of metals by applying a lubricant

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Medium films based on resins have a certain importance. For example, from DE-OS 29 34 138, one of the others Known as a suitable lubricant for metalworking, which is an adduct of melamine and cyanuric acid or contains isocyanuric acid. The liquid phase of the lubricant can be water, organic solvent, or mineral oil contain synthetic oil. The melamine / cyanuric acid or isocyanuric acid adduct can also be incorporated into a film-forming resin composition such as an aqueous polymer dispersion Synthetic or natural resin paint or incorporated into a paint made from a thermosetting liquid resin.

Although resin-based coatings for certain applications Having advantages, they are especially flawed in the preparation of metals for cold working. For example, chatter marks occur during wire drawing and the wire often breaks.

The object of the invention is to provide a method to facilitate the cold forming of metals to provide the disadvantages of the known, in particular the aforementioned method does not have, flawless cold forming is permitted, the remaining residues can be easily removed and is easy to carry out.

The object is achieved by the method of the opening paragraph named type is designed according to the invention in such a way that you first apply an aqueous one to the metal surface Solution or dispersion of a water-soluble thermoplastic resin with a content of melamine / cyanuric acid or isocyanuric acid adduct applies and dries up and then applies a metal soap and / or a lubricating oil.

As thermoplastic water-soluble resins are recommended Polyacrylic acid, copolymers of acrylic acid and others

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Vinyl compounds, polyacrylamide, polyvinylpyrrolidone, copolymers of maleic acid and of vinyl compounds, saponification products of polyvinyl acetate, etc. As vinyl compounds with copolymerized acrylic acids or maleic acids are, for example, vinyl acetate, styrene, methyl vinyl ether, acrylamide, Vinyl pyrrolidone listed. In the properties of removability of the residue remaining after cold forming are superior to acrylic acid resins.

A preferred embodiment of the invention provides that an aqueous solution or dispersion is first applied, which contains resin to adduct in a weight ratio of 1: 0.3 to 1: 2. If the ratio is greater than 1: 0.3 it falls the lubricating property, with a value of less than 1: 2, the binding effect of the resin decreases, so that the Adhesive properties of the coating deteriorate. Possibly The coating can also peel off during cold forming and chatter marks can arise.

The aqueous solution or dispersion of melamine / cyanuric acid adduct and resin should not contain any surfactants. Surfactants deteriorate the adhesion properties of the thermoplastic water-soluble Resin on metal. They can also lead to softening of the resin coating, so that the good lubrication results are lost.

The weight of the dried coating should preferably be 0.3 to 30 g / m 2. Below the layer weight of 0.3 g / m decreases the lubricating properties, that is, on the Chatter marks or grooves and signs of wear and tear on the tool can occur on metal surfaces. At a shift weight Adhesions above 30 g / m 2 can occur, so that work performance ultimately deteriorates. For the Cold forming by pressing a layer weight is recommended

2
from 0.5 to 2 g / m, for cold deformation by wire or

2 pipe pull one of 5 to 15 g / m.

Melamine / cyanuric acid adducts - the term cyanuric acid is also understood to mean isocyanuric acid - can be used produce by mixing an aqueous melamine solution and an aqueous cyanuric acid or isocyanuric acid solution and that separating precipitated adduct. It can also be obtained by adding melamine or cyanuric acid or isocyanuric acid or else both dispersed in the solid phase in water and allowed to react with one another. In the latter case, the particle diameter should of the starting materials are approximately in the range of 0.5 to 5 / µm.

In the second process stage, metal soap and / or are used Lubricating oil applied. Suitable metal soaps are, for example, soaps based on calcium stearate, barium stearate, Zinc stearate, sodium stearate and lithium stearate. You can have an addition of calcium carbonate, talc, graphite and / or molybdenum disulfide. Suitable lubricating oils are, for example commercial oils and fats or mineral oils.

The application of the aqueous solution or dispersion of resin and melamine / cyanuric acid adduct to the metal surface takes place in the usual way, e.g. by dipping, spraying, brushing, pouring over and rolling up. After that one generally leaves first dry at ambient temperature, which can take about 30 minutes and more. After that, under Further dried under the influence of heat. Metal soap and / or lubricating oil are then applied.

The implementation of the process in the aforementioned two-stage form is necessary because the simultaneous application of the Solution or dispersion of the thermoplastic water-soluble resin and the melamine / cyanuric acid adduct together with Metal soap and / or lubricating oil does not allow the aim pursued by the invention to be achieved. A one-step way of working would reduce the adhesion of the thermoplastic water-soluble resin

deteriorate on the metal surface and upon deformation lead to the peeling of the coating and thus to chatter marks.

During the deformation process, the coating does not come off in any phase of the cold working. There is no contact between the metal surface and the tool, although the temperature of the metal surface rises ^{to about 100 to 150 ° C. as a result of the deformation and frictional heat of the metal.} Nevertheless, the elasticity of the coating is so high that it adapts well to the change in shape of the workpiece and does not tear.

Since the melamine / cyanuric acid or isocyanuric acid adduct ^{does not decompose up to 300 °} C. and has good lubricating properties, it acts as a lubricant in cold working. The coating of water-soluble resin and melamine / cyanuric acid adduct separates in two stages. The lower layer, which is located close to the metal surface and has increased components of thermoplastic water-soluble resin, improves the adhesive properties in particular, while the upper layer improves the lubricating properties of the coating in particular.

With the invention it is possible, in contrast to the conventional coating formation, by applying lubricant during cold forming of metals to save energy, to simplify the pretreatment process and to reduce environmental damage. Simultaneously has succeeded in providing a coating that has a good lubricating effect achieve.

The invention is illustrated by way of example and in greater detail on the basis of the following examples.

Examples 1 to 5

Steel wire of stainless steel 304 was pickled with acid, washed with water and immersed in a treatment solution of water-soluble resin and melamine / cyanuric acid adduct in accordance with Table 1 for 1 minute at 30 ⁰ C. After draining and natural drying in the course of 1 hour, drying was carried out with hot air at 120 ^° C. for 30 minutes and a solid coating was formed. Calcium stearate powder was then applied and drawn in the wire drawing bench. The drawing conditions were:

Processing steps: Dimensions: Reduction in cross section :

- Output wire: 2.30mm 0

- 1st pass: 1.92 mm 0 27.4%

- 2nd pass: 1.72 mm 0 20.0%

- 3rd pass: 1.54 mm 0 20.0%

- 4th pass: 1.38 mm 0 20.0%

- 5th pass: 1.23 mm 0 20.0%

Drawing speed 50 m / min.

The tensile force was measured, the appearance of the wire and the removability property were observed of the coating remaining on the metal surface was examined. The results are given in TABLE 2.

Examples 6 to 10

In the same manner as described in Examples 1 to 5, pipes made of SUS 304 stainless steel with a solid coating were made Mistake. Then, after applying lubricating oil (rapeseed oil), the draw bench was pulled. The drawing conditions were:

Test material: 2.5 cm in diameter before drawing

2.5 mm wall thickness

200 cm length

Reduction of cross section: 40%

Drawing speed: 17.8 m / min

The pulling forces and the plug forces were measured. Furthermore, the external appearance after drawing was observed, and the removability of the smear layer was examined. The results are shown in TABLE 3.

Examples 11-15

SUS 304 stainless steel sheets were coated on one side using the same treatment solutions as in Examples 6 to 10 so that a coating of 3 µm was obtained after drying. The mixture was then dried in hot air at up to 120 ⁰ C. Then lubricating oil (machine oil) was applied to the same side and deep-drawn in the deep-drawing test press.

Deep drawing conditions:

- Test material: 90 0 χ 0.8 mm

- Deep drawing test: flat-bottom cylinder drawing

Wrinkle Suppression Force: 20,000 Newtons

The results of the appearance after deep drawing and the removability of the remaining coating is shown in TABLE 4.

Comparative experiment 1:

Stainless steel wire of the quality mentioned in Examples 1 to 5 was pickled with acid, washed with water, with

2
provided with an oxalate coating of 10 g / m layer weight.

This was followed by washing with water and metallic soap in one

2
Amount of 4 g / m applied. After drying, the same conditions as in Examples 1 to 5 were used for pulling. The results are shown in Table 2.

Comparative experiment 2:

Stainless steel wire of the quality mentioned in Examples 1 to 5 was pickled with acid, washed with water and after drying, immersed in a resin diluted with solvent for 1 minute at room temperature. Subsequently was Naturally dried for 1 day and grown under the same conditions as specified in Examples 1 to 5. The amount of resin applied was 10 g / m 2. The results are shown in Table 2.

Comparative experiment 3:

The pulling test according to Example 2 was repeated, except that it contained the treatment solution applied in the first stage no melamine / cyanuric acid adduct. The amount of resin applied

2
was 10 g / m. The result of the experiment is shown in Table 2

laid down.
Comparative experiment 4:

The procedure was as in Example 1. However, no calcium stearate was applied. The result of the experiment contains table 2.

Comparative experiment 5:

Stainless steel pipes of the same quality as used in Examples to 10 were pickled with acid, with water washed, provided with an oxalate coating of 12 g / m and washed again with water. After drying, metal

2
soap applied in an amount of 4 g / m and under the

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the same conditions as in Examples 6 to 10 drawn. The results are shown in Table 3.

Comparative experiment 6:

Stainless steel pipes of the quality mentioned in Examples 6 to 10 were pickled with acid, washed with water and after drying, immersed in a resin diluted with solvent for 1 minute at room temperature. Subsequently was Naturally dried and lubricating oil applied for 1 day. Eventually it was under the same conditions as drawn in Examples 6 to 10. The amount of applied

2 resin was 10 g / m. The results are shown in Table 3.

Comparative experiment 7:

The pulling test according to Example 7 was repeated, only the treatment solution applied in the first stage was free from Melamine / cyanuric acid adduct. The amount of carmine applied was included 10 g / m. The test result is given in Table 3.

Comparative experiment 8:

The experiment according to Example 6 was repeated, but no lubricating oil was applied. The result of the experiment is given from table 3.

Comparative experiment 9:

Analogously to Examples 11 to 15, an acrylic resin film of 3 μm was applied to stainless steel plates and then with Lubricating oil of 3 / um provided. It was under the conditions of Examples 11 to 15 deep-drawn. The results are shown in Table 4.

To determine the removability of the after cold forming

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remaining residues (Tables 2 to 4) were worked with an alkaline degreasing ^{solution, in which the deformed metal objects were immersed at 80 0} C for 1 hour. The removal of the lubricant residue was assessed with the naked eye.

Table 1 Composition examples

1 + 6 2 + 7 3 + 8 4 + 9 5 + 10 thermoplastic water-soluble resin (in% by weight):

- polyacrylic acid

(Degree of polymerisation 500 - 1000) 4

- saponification product of 97% modified Polyvinyl acetate

(Degree of polymerisation 1500 - 2000) 9 2

- vinyl acetate - acrylic acid - copolymer (1: 1) (Degree of polymerisation 500 - 1000) 6

- saponification product of 87% modified Polyvinyl acetate

(Degree of polymerisation 500 - 1000) 4

- polyvinylpyrrolidone

(Molecular weight 900,000) 8

- Maleic acid - methyl vinyl ether - copolymer

(GANIREZ AN 139) 7

Melamine - cyanuric acid adduct.

(Particle diameter 0.5 to 5 microns) 8 7 10 10 8 ^

Water 84 84 82 83 84 co

solid cover: weight (g / m2) 10 13 13 11 12 f'O

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Table 2: test results

Test: Wire drawing test (drawing force in units of

10 Newtons)

Number of passes: 1. 2. Appearance removability
wire d, lubricants after debris
Draw

4th

5. Passage Well 69 defect free Well 68 defect free Well 70 defect free Well 70 defect free Well 69 defect free

Example:

121 120 123 124 125

Comparative experiment:

107 106 108 108 107

100 100 101 103 102

78 76 79 80 80

126 107 101 78

122 107 Chatter marks, wire torn

129 106 103 chatter marks,

Wire torn

Chatter marks, wire torn

faultless bad

flawed bad

faulty good

faulty good

Note: The lower the pulling force, the better the lubricating properties. Table 3: Test results

Attempt: Pulling test
Matrix plugs
force * force *
.because? ίη units of 540 Appearance of the pipes
after pulling
10 newtons Removability
of the lubricating
medium return
state Example: 580 6th 6,300 560 defect free Well 7th 6,500 600 defect free Well 8th 6,400 610 defect free Well 9 6,600 defect free Well 10 6,700 700 defect free Well Comparison
attempt: 690 5 7,100 660 defect free bad 6th 7,200 - flawed bad 7th 7,000 flawed Well 8th - while pulling
Broken stopper;
Impossible to pull

♦ The lower the values of the die force and the plug force, the better the lubricating properties.

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Table k

Together Look after the setting: Deep drawing Example: 11 without pull marks 12th ti 13th dd 14th π 15th ti Comparative attempt:

Entfembarkext of the lubricant residue

Well ti

ti

Cracked floor

Claims (3)

Claims 1. A method for facilitating the cold working of metals by applying a resin-based lubricant film, characterized in that an aqueous solution or dispersion of a water-soluble thermoplastic resin containing melamine / cyanuric acid or isocyanuric acid adduct is first applied to the metal surfaces and dried and then applying a metal soap and / or a lubricating oil. 2. The method according to claim 1, characterized in that an aqueous solution or dispersion which contains resin to adduct in a weight ratio of 1: 0.3 to 1: is applied. 3. The method according to claim 1 or 2, characterized in that an aqueous solution or dispersion is applied in such a way that, after drying, a layer weight of 2 0.3 to 30 g / m 2 results.