DE3043959A1 - METHOD AND DEVICE FOR PRODUCING A WIRE FROM STEEL FOR REINFORCING ITEMS FROM RUBBER, IN PARTICULAR TIRES - Google Patents

Description

The invention relates to a method for producing metal wires for reinforcing articles made of rubber, in particular pneumatic tires. The invention particularly relates to the production of coated steel wires.

Steel wires coated with a brass layer are used to reinforce objects made of rubber. Main task The brass is the establishment of a suitable bond between the rubber and the steel, with the brass also plays an important role during wire drawing. Generally brass with 60 to 75% copper is used used.

Investigations have shown that brass is used for good adhesion with various types of rubber, especially with aging must be used with a layer with a higher zinc content on the surface.

This zinc gradient can be achieved in different ways. E.g. by alternately coating the steel wire with copper and zinc layers, the last layer being zinc and subsequent thermal diffusion. if the thermal diffusion is not complete, there will be one at the

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" ⁴ " 3043953

Zinc-enriched layer achieved on the surface. Another method according to FR-PS 2 393 856 is that on a Wire coated with a brass of conventional composition, a thin layer of zinc is applied. After wire drawing, a brass with an inhomogeneous composition is obtained, which is rich in zinc on the surface.

With such a treatment, good adhesion behavior is actually achieved during aging. The procedure has but disadvantages. The presence of a zinc-rich layer on the surface creates disturbances in drawing. The specified The patent states that the optimal zinc deposit is about 0.06 g / kg wire and that starting from 0.1 g zinc per kg of wire, problems arise when pulling. Nevertheless, in According to the patent, it is expected that the degree of precipitation of the zinc will go up to 50 χ 10 ~ ^ mg / mm 'of the application area can, which corresponds to an amount of 0.3 g / kg in the case of the wire with the smaller diameter mentioned in the patent specification.

Now, however, additional tests have shown that the best results in terms of adhesion only for zinc quantities of over 0.1 g / kg, preferably between 0.3 and 0.7 s / kg »can be achieved. However, in this case, the problems in drawing become very critical and make this process from an industrial point of view totally impossible.

On the other hand, especially for zinc amounts from 0.1 to Oj .3 g / kg and above found that the pulling problems were aggravate with the storage life of the wire before pulling. So the difficulties are greater if the wire, for example, two months is drawn after galvanizing as if ex: e.g. drawn on the same day. This phenomenon is explained by layers with intermediate phases are formed at the brass-zinc interface by diffusion under ambient conditions, which are brittle and non-deformable and which themselves contribute

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very small thickness make the wire undrawable under industrial conditions (numerous breaks, heavy wear of the drawing iron). The larger the zinc layer, the more pronounced this phenomenon is.

The object of the invention is to create a method that has good adhesion behavior during aging and at the same time allows pulling under good industrial conditions.

The invention relates to a method for production a wire made of steel for reinforcing objects made of rubber, in particular pneumatic tires, with one for the Wire drawing suitable brass-plated wire a zinc layer is applied and the wire afterwards to produce the desired Diameter is drawn, which is characterized by the application of an amount of zinc from 0.1 to 1 g / kg steel and through continuous drawing of the wire together with the galvanizing process.

The amount of zinc applied is preferably 0.1 to 0.6 g / kg steel.

The zinc is preferably applied electrolytically Precipitation as the wire passes through a suitable electrolytic bath. Everyone can do it when galvanizing The types of bath used are: cyan-based bath, basic non-cyanized bath, acidic bath, pyrophosphate bath nsw. Non-toxic baths are preferably used.

The brass is carried out according to conventional methods: electrolytic precipitation or brassing by thermal diffusion. It becomes a common brass with 60 to 75% copper used, the deposited amount being 2 to 7 g / kg steel. Before galvanizing, a light rusting can be carried out. The steel is a at

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hardened ones commonly used in this type of application patented steel. The diameter of the treated wires is preferably 0.80 to 1.90 mm, but can vary are also outside these limits. Continuous drawing with galvanizing takes place under normal conditions regarding the parameters (speed, number of passes, number of dies, type and shape of dies, Lubricants, etc.) · The speed is preferably 10 to 25 m / sec.

The method can be carried out by an apparatus according to the invention which contains a cell for electrolytic galvanizing connected to a wire drawing machine. The device according to the invention preferably has a galvanizing cell which is regulated after the operation of the wire drawing machine. According to the control system, the electrical current is only switched on when the wire drawing machine is running has reached normal working speed. The circuit is automatically interrupted when the wire drawing machine stands still.

Advantageously, according to the invention, the direct current supply, starting from the alternating current network, takes place via a rectifier with regulated intensity. This system is advantageous over the constant voltage system. By the phenomenon of polarization a deposit forms on the anode, increasing the resistance of the circuit. When the tension is held constant, the intensity decreases at the same time as the resistance increases, with that proportional to the intensity the amount depressed is also decreasing. There is irregular precipitation. Condition according to the invention the regulation and the supply with constant intensity a regular precipitation, consequently a regular one Product.

130023/0651 ORIGINAL INSPECTED

The invention is described, for example, with reference to the drawing. It shows:

Fig. 1 is a schematic representation of a front

direction for performing the method according to the invention;

Figure 2 is a graph of the benefits

the invention;

Fig. 3 is a graphic representation of a change

change of the brass composition as a function of the depth for according to the Invention treated wires.

The apparatus according to FIG. 1 mainly contains an electrolytic galvanizing cell 1 and a partially illustrated wire drawing machine 2 arranged in a downward direction of movement. The galvanizing cell 1 contains a trough 3 with a bath through which a brass-plated wire F passes. The brass-plated wire is supplied from a supply reel 4. The bath circulates in a closed circuit by means of a pump 5, starting from a container 6. It is fed into the trough through an inlet line 7 and emptied at the two ends of the trough through lines 8 and 0 which lead it back to the container 6. The anode consists of a basket 10 in which Zirkabletten are placed. The wire F is connected to the cathode via the axes of guide wheels 11 and / or 12 which are located at the entry and exit of the trough 3. The wire is drawn through the trough by the wire drawing machine 2. At the outlet of the bath, the galvanized wire is rinsed in a trough 14. The wire then continuously penetrates the wire drawing machine 2, of which only two drawing dies 15 and two drawing rollers 16 are shown. The one under normal conditions

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Drawn wire is drawn on any suitable, not shown Carrier added. The device also contains a device, not shown, for regulating the operation the galvanizing cell after the operation of the wire drawing machine. According to this device, the galvanizing cell is only in Operation is set when the wire drawing machine has reached its normal operating speed. The operation of the galvanizing cell stops at the same time as that of the wire drawing machine. The device also has one not shown Establishment of known design for power supply with regulated intensity.

In order to demonstrate the advantages of the invention, a number of experiments were carried out which are the subject of the following examples are:

example 1

This example concerns tests for the behavior of adhesion with aging.

The adhesion test is carried out on a strand in the following way;

Is used a rubber A for the production of calendered sheets with the strand to be tested, wherein these layers are aged in a strictly controlled atmosphere during 5 weeks at 21 ⁰ C and 65% relative humidity. At time zero and every week, cord covered with rubber cord is removed, which is placed in an adhesion test specimen which is standardized in accordance with the American standard ASTM D 2229-73 and which in turn is made of rubber A. The posture is measured by the method according to this standard.

The results are in Table 1 and the graph indicated by Fig. 2, in which the aging time T as Abscissa and the liability expressed in dean newtons as ordi-

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nate are given.

l§r? E2ii consists of a strand with the designation 4 χ 0.25 S 12.5 and thus from 4 wires with a diameter of 0.25 mm, which are twisted with an S-twist and have a lay length of 12.5 mm. The wire with a diameter of 0.25 mm is made by pulling a wire with a 1.25 mm diameter and drawn from patented hard steel. Before drawing, the wire was made with a diameter of 1.25 mm coated with a layer of brass, in the ratio of 5.8 g of brass per kg of steel wire, the brass Contains 66% copper and 34% zinc. After pulling, a Brass-plated wire with a diameter of 0.25 mm obtained with 5 g / kg brass with 65.8% copper and 34.2% zinc. The weight loss of 0.8% o Brass is a normal loss that is often seen when pulling. Based on this Wire a strand of 4 χ 0.25 S 12.5 is produced and the adhesion test is carried out on this strand.

The results are in Table 1 and the graph of Fig. 2 (curve A).

Ib: The above adhesion test is carried out on a strand, made from a first wire treated according to the invention is. The initial wire is identical to that of Example 1a, thus has a diameter of 1.5 mm and is coated with a brass made of 66% copper and 34% zinc in a ratio of 5.8 g brass per kg steel wire. Afterward According to the invention, a zinc coating in a ratio of 0.15 g zinc per kg steel wire is applied to the brass. Man receives a wire with 5.95 g of coating per kg of steel wire, its average composition, before entering the wire drawing machine 64.5% copper and 35.5% zinc. The wire is continuously along with the galvanizing under the conditions drawn to the invention. You get a thin wire with a

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Diameter of 0.25 mm and plated with 4.8 g / kg brass with the total composition of 65% copper and 35% zinc. For this Wire, a strand 4 χ 0.25 S 1.25 is produced as in Example 1a and the same adhesion test is carried out on this strand.

The results are in Table 1 and the graph of Fig. 2 (curve B). There is already a clear improvement in the aging behavior.

Icj: The above adhesion test is carried out on a strand, which is made from a second wire according to the invention.

The starting wire is identical to that of Examples 1a and 1b. Then, according to the invention, galvanizing takes place, the amount of zinc being 0.5 g / kg of steel wire. Before entering the wire drawing machine, a wire is obtained with a coating amount of 6.3 g / kg, the total amount of which consists of 60.5% copper and 39.5% zinc. The wire is continuously drawn together with the galvanizing under the conditions of the invention. After drawing, a thin wire with a diameter of 0.25 mm and coated with 5.6 g / kg of brass with a total composition of 62% copper and 38% zinc is obtained. A strand 4 χ 0.25 S 12.5 is produced from this wire, as in Examples 1a and 1b, and subjected to an adhesion test.

The results are in Table 1 and the graph of Fig. 2 (curve C).

It is a significant improvement in adhesion performance determine the aging.

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Table 1

at
games Liability in the Dean Newton (-daN) l Voche 2 W.-. 3 W.. 4 W. 5 W, Sample:
1a 'Time 6 21.2 18.2 16.2 Π, 3 17th 1 b 38 28.3 26.8 24.2 23.3 21.2 1 c 37 32.a 'ί 31 30.8 30, U 30.6 36

The above examples correspond to a storage period of calendered Lay before the manufacture of pneumatic tires. It is note that the improvement in the adhesion behavior with aging with the amount of zinc applied to the surface increases.

The amount of zinc applied to the surface prior to wire drawing partially mixes with the brass during wire drawing due to mechanical phenomena and the partial Thermal diffusion. A finished wire is obtained which is coated with brass of inhomogeneous composition and attached the surface is rich in zinc, as shown by surface analyzes carried out by means of photoelectron spectroscopy ESCA (Electron Spectroscopy for Chemical Analysis) show.

The graph according to FIG. 3 indicates the value of the atomic percentage as a function of the depth or "layer depth" Copper, measured on the basis of intensity maxima which correspond to the electron energy levels 2 ρ 3/2. The analysis will carried out on three wires: test wire according to example 1a and wires according to examples 1b and 1c.

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The following is to be noted:

- The composition of brass is developing in general for the three wires according to the depth: the copper content increases with depth and then practically stabilizes at about 500 A,

- In the wires treated according to the invention, the brass on the surface is poorer in copper: when approaching the above adhesion results confirm that the adhesion behavior during aging with the zinc content on the surface increases.

Example 2

This example is intended to show that the drawability of the wire is not affected by the zinc coating when in accordance with the invention the drawing takes place continuously together with the galvanizing.

2a: The test wire is a brass-plated wire with a Diameter of 1.25 mm according to Example 1a and is subjected to drawing under the usual conditions for production of a wire with a final diameter of 0.25 mm. Of the The test consists in measuring the distance in km on the drawn wire before the drawing dies have to be changed, taking into account the usual tolerances in the diameter of the finished wire. This distance is given for the trial wire by the base number 100 expressed.

2b_: The treated wire is the wire according to example 1b, i.e. the wire according to Example 1a coated with 0.15 g / kg zinc. He is continuously taking along with the galvanizing Conditions identical to those of the test wire of Example 2a were drawn. The drawn length before changing the drawing iron returned to base 100 is 120.

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£ The wire treated is the wire according to the example 1c, i.e. the wire according to example 1a, coated with 0.5 g / kg zinc. He will be ongoing along with the galvanizing drawn under conditions similar to those of the trial wire of Example 2a are identical. The drawn length before changing the dies, traced back to the base 100, is 95.

2d: A wire is used which has a treatment according to the PR-PS 2 393 856 has learned. The output wire is that Brass-plated wire of Example 1a, coated with 0.35 g / kg zinc. After tine, the wire is stored for 15 days and then drawn under the same conditions as the test wire of Example 2a. The length drawn before changing the The drawing iron, returned to the base 100, is 5 to In addition, it can be seen that the wire is very irregular and that fractures occur frequently. Pulling under industrial conditions is not feasible.

Example 2 shows that, in contrast to the known processes, that neither particular drawing difficulties nor an increase in the difficulties with the deposited on the surface Amount of zinc occur when, according to the invention, the drawing is carried out continuously together with the galvanizing. if on the other hand, is drawn discontinuously according to the prior art, great drawing difficulties occur, which are related to the content of applied zinc and the duration of the interim storage increase.

Examples 1 and 2 together make the "advantages of the invention." apparently:

- No difficulty in pulling with deposits of Zinc up to 1 g / kg steel,

- Adhesion behavior during aging: compared to the state

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the technology significantly improved due to the larger deposits from zinc up to 1 g / kg steel.

Example 3

This example is intended to demonstrate the improvement in the adhesion behavior with aging.

The test is carried out in the following way:

A calendered layer with a rubber B is produced with the wire to be tested. Samples are prepared, each of which is formed by cutting two pieces of the sheet which are placed on top of each other in a 90 ° crossed manner. Aging takes place in a climatic cabinet at 35 ^° C. and 98% relative humidity with the aim of reproducing the storage conditions in the tropical climate. The samples are aged for 0, 3, 6, 9 or 15 days, after which they are vulcanized. After vulcanization, the two layer particles are torn apart, with a rating from 0 to 5 depending on the rubber coating adhering to the wires: the rating 5 corresponds to a maximum coating, while the rating 0 corresponds to a coating of size 0.

The test wire is made of a steel wire with a diameter of 1.25 mm and a brass coating of 65% copper in proportion of 4.7 g / kg. Under normal conditions, the wire is drawn up to a diameter of 0.25 mm. Man receives a wire with a diameter of 0.25 mm, coated with a brass of 64.5% copper in the ratio of 4 g / kg. From this wire, as in the previous examples, a strand 4 χ 0.25 S 12.5 is made, the following Test is subjected. The following results are obtained:

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Table 2

Days 0 3 6 9 15 Grade 5 3 10 0

Thereafter - a test is carried out on one by the method according to the Invention made wire.

The starting wire is a brass-plated steel wire with a diameter of 1.25 mm, the amount of brass being 4.5 g / kg and its composition being 9.5% copper and 31.5% zinc. This brass-plated wire is galvanized in a ratio of 0.4 g of zinc per kg of steel . You get "yrler after αένα. Galvanizing and before entering the wire drawing machine with

an amount of brass of 4.9 g / kg with a total of 63.8% copper is over,
drawn-y-The galvanized wire is drawn continuously according to the invention. After drawing, a brass-plated wire with a final diameter of 0.25 mm is obtained, the amount of brass being 4.1 g / kg with a total composition of 65% copper and 35% zinc. The wire is processed as strand 4 χ 0.25 S 12.5, which is subjected to the above test. The following results will be obtained:

Table 3

Days 0369 15

Grade 5 5 5 5 4

It's a huge improvement in adhesion the aging in which by. The method according to the invention

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established wire.

Example 4

This example is intended to show the adhesion behavior during aging. It is one carried out in an autoclave Aging test in the presence of moisture at 120 ° C for 8 days at a pressure of about 2 bar. Liability is carried out with a rubber C in accordance with the ASTM - D 2229-73 standard Test specimens measured.

The samples consist of two strands 4 0.25 S 12.5 and 5 x 0.25 S 9.5t, the wires of which were produced by drawing a brass-plated steel wire with a diameter of 1.25 mm. The tests were carried out on strands with a structure identical to the samples formed by the wires made by the same process as the wires of the samples with the difference in the application of the galvanizing according to the invention.

The results are shown in Table 4:

- The "Construction" column shows the structure of the strands.

- The column "Brass: wire AZ" concerns the brass-plated Wire before galvanizing and gives the amount of brass deposited in g / kg in relation to the steel and the percentage of copper in this brass on.

- The "Zn addition" column shows the amount of zinc applied in g / kg in relation to the steel for the case of wires according to the invention.

- The column "Me: wire AT" gives the amount of brass after the Zinc plating and before wire drawing and the total percentage of copper in that brass.

- The column "Me: Litze" _% indicates the amount of brass remaining after wire drawing and the total percentage of copper in this brass.

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- In the "Adhesion" column, measured according to the ASTM D 2229-73 standard, A _Q denotes the initial adhesion before passage in the autoclave and A ₀ the adhesion after 8 hours in the autoclave, expressed in daN.

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Table 4

C? O N> CO -ν. O CD OI

I. Me: Wire AZ Z Cu Zn - Me.: Wire '.AT, \ Cu Me :. Strand Tsp Cu Liability. λ
a ! forgive construction g / kg 66.5 to
sentence ' g / kg 66.5 g / kg 65.7 A.
O 18.0 number 5.6 69, A 0
sample 5.6 65 4.5 67 A7.0 33.5 Al 5.3 68.8 0.35 5.65 63.5 5.1 65.2 53.5 3A.5 42 5 χ 0.25 S 9.5 A.2 67.5 0.35 A, 55 67.5 3.6 68 50, c 13th A3 A, 8 68.0 O
sample A, 8 63.6 3.9 65.5 AO, S 25th AA 4 χ 0.25 SLL2.S A.2 0.35 A, 55 3.9 A3.5 A3
I.

Oo ι

co cn

CD

Comment;

On the first test strand 41 there is a large decrease in adhesion between the initial adhesion and after passage in the autoclave ascertain.

On the strand 42, made from wires treated according to the invention, it can be seen that if the adhesion at time O is in the same order of magnitude as with strand 41, the loss of adhesion with aging, however, is much lower.

The same versions are used for strand 45 in comparison with strand 44 close.

There is also a slight decrease in adhesion for the strand 43.

The above examples show the advantages of the invention, which is an improved adhesion behavior with aging compared to the known method in connection with a good drawability of the wire allows.

The invention is applicable to steel wires for reinforcement of articles made of rubber, in particular for reinforcing pneumatic tires.

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Claims (1)

PATENT CLAIMS Method of making a wire from steel for reinforcement of articles made of rubber, in particular pneumatic tires, with one suitable for wire drawing A zinc layer is applied to brass-plated wire and the wire is then used to produce the desired diameter is pulled, characterized by applying a zinc amount of 0.1 to 1 g / kg steel and by continuously pulling the wire along with the sinking process. Process according to Claim 1, characterized in that the amount of zinc applied is 0.1 Ms 0.6 g / kg of steel. Method according to claim 1 or 2, characterized in that that the application of zinc by electrolytic deposition 130023/0651 blow occurs. 4. The method according to any one of claims 1 to 3, characterized in that that the galvanizing is applied to a brass-plated wire, the amount of brass of which is 2 to 7 g / kg Steel is. 5. Device for performing the method according to a of Claims 1 to 4, characterized by a wire drawing machine (2) arranged upwards in the direction of movement Cell (1) for electrolytic galvanizing. 6. Apparatus according to claim 5, characterized in that the operation of the cell (1) is regulated after the operation of the wire drawing machine (2). 7. Apparatus according to claim 6, characterized in that the electrolytic power supply with constant intensity he follows. 130023/0651