JPH08209387A - Brass plated steel wire having excellent drawability - Google Patents

Abstract

PURPOSE: To produce a brass plated steel wire having excellent drawability by regulating the sizes of Cu plating particles and Zn plating particles particularly before diffusion plating or the gaps after diffusion, with respect to an improvement in the brass plating of the steel wire for steel cords produced by drawing for reinforcing rubber. CONSTITUTION: This brass plated steel wire 2 is formed by specifying the sizes of the Cu plating particles 1 and the Zn plating particles before diffusion plating respectively to 0.05 to 5μm in brass diffusion plating to successively precipitate Cu and Zn by electroplating on a steel base and to alloy both by subsequent thermal diffusion and has the excellent drawability. The sizes of the gaps 3 in the surface layer parts formed by these brass plating particles are 0.02 to 3μm as the distance between the average particles at apertures. The lubricant at the time of drawing are stored in these gaps 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in brass plating of a steel wire for steel cord for rubber reinforcement which is produced by wire drawing, and particularly, to improve the size or voids of Cu plated particles and Zn plated particles before diffusion plating. The present invention relates to a technique for improving wire drawing workability by regulating the wire drawing workability.

[0002]

2. Description of the Related Art At present, there are various industrial technologies for embedding a steel wire in rubber to improve the strength and durability of the rubber. In particular, it is often used for automobile tires, high-pressure rubber hoses, conveyor belts, and the like. Generally, automobile tire cords are cold drawn to a wire diameter in an extremely fine area of about 0.2 mm. At this time, the brass wire is used to improve the drawing lubrication and improve the adhesion with rubber. Apply plating. At this time, the adhesiveness changes due to factors such as the surface Cu concentration after the wire drawing, the thickness, and the surface condition.
It is particularly important not only to control the liquid flow velocity during plating, the current change, the die during wire drawing, the area reduction ratio, but at the same time to improve the wire drawing workability of steel wire. Is getting tougher.

On the other hand, brass plating does not satisfy this regulation in the conventional alloy plating using a cyan bath due to pollution problems. Therefore, instead of diffusion plating in which Cu and Zn plating are performed individually and then heat diffusion is performed. It is coming.
This diffusion plating method has a great advantage in terms of adhesiveness with rubber, but some improvement is required to improve drawability of steel wire. Improvements to add that benefit include:
It is desired to develop a technology for imparting an improvement in wire drawing workability to a diffusion plated steel wire.

Further, as a known technique in this field, for example, in JP-A-58-84992, a method of suppressing β brass which deteriorates wire drawing workability within a range of β / (α + β) = 10 to 30%. However, Japanese Patent Application Laid-Open No. 62-23977 discloses a method of suppressing the generation of an oxide layer which causes deterioration of wire drawing workability and die life as much as possible by quenching Cu and Zn with water immediately after thermal diffusion. However, the control of β brass and oxide layer of these known techniques is a good means for wire drawing workability, but the control method is difficult, and even if the material is rapidly cooled with water, it is necessary to adjust the quenching rate, etc. Has a problem in terms of equipment cost. Further, as the plating thickness becomes thicker, the diffusion migration distance of Cu and Zn becomes longer, so that it becomes more difficult to control.

[0005]

SUMMARY OF THE INVENTION In view of the above conventional problems, an object of the present invention is to improve the lubricity during wire drawing by controlling the size of Cu and Zn plated particles after diffusion plating. Provided is a brass-plated steel wire having excellent wire drawability that facilitates process control and reduces manufacturing costs.

Another object of the present invention is to adjust the voids in the plating layer formed by Cu and Zn plated particles after diffusion plating so that the liquid lubricant in wet lubrication can be held more effectively. Provide a brass-plated steel wire excellent in wire drawing workability.

[0007]

Means for Solving the Problems The present invention is to solve the above-mentioned problems, and the gist thereof is as follows: (1) Cu and Zn are sequentially deposited on a steel substrate by electroplating, followed by heat treatment. In brass diffusion plating for alloying by diffusion, the sizes of the Cu-plated particles and the Zn-plated particles before diffusion plating are each 0.05 to 5 μm.
m, a brass-plated steel wire excellent in wire drawing workability, characterized in that a lubricant during wire drawing is stored in the void after thermal diffusion,

(2) C on the steel substrate by electroplating
In brass diffusion plating in which u and Zn are sequentially deposited and then alloyed by thermal diffusion, the size of the voids in the surface layer portion formed by the brass plating particles after diffusion plating is 0. It is a brass-plated steel wire having an excellent wire drawing workability, which is characterized in that it has a diameter of 02 to 3 μm and stores a lubricant during wire drawing in the void.

[0009]

From a number of experiments, the inventors of the present invention have found that the plated particles on the steel species are almost spherically precipitated, and a slight void is generated between the particles, and the wire drawing lubricant enters and is stored in the void. Based on the finding that it is possible to improve the lubricating ability during wire drawing, the size of the plating particles or the opening of the voids formed by the plating particles are not controlled without controlling β-brass and surface oxide layer as in the past. By defining the portion, it was easy to put the wire-drawing lubricant in, and it was easy to hold the wire-drawing lubricant, and it was possible to improve drawability.

An example of the surface condition after plating is shown in FIG. 1 as an explanatory view. In this figure, FIG. 1 (a) shows the surface condition of the steel wire after diffusion brass plating, and FIG. 1 (b) is an enlarged view of a part of the surface after brass diffusion plating of FIG. 1 (a). is there. It can be seen that the brass-plated particles 1 are considerably porous after the diffusion plating, and the Cu and Zn particles are substantially spherical and are aligned and deposited. Furthermore, the voids 3 they form have openings with an open surface and can hold solid and liquid lubricants up to a depth of several layers.

In this case, the voids are substantially determined by the size of adjacent particles, and the voids are formed even if the particles are randomly arranged. Furthermore, FIG.
As shown in (b), it is possible to control the particle size and the voids within appropriate ranges by changing the current density from the characteristics of electroplating. In the distribution state, large plating particles 4 and medium plating particles 5 are used.
And, if the ratio of the small plating particles 6 is preferably 30%: 40%: 30% in volume ratio, the voids in an appropriate range are expressed. That is, by controlling the current value of electroplating, the distance between the particles is controlled, and the voids are also controlled within the required range. As a result, the ease with which the lubricant enters can be adjusted. In this case, if the gap is too large,
If the lubricant is too small, it will be difficult for the lubricant to enter. The lubricant used in the present invention has the same effect on solid and liquid lubricants of any component.

In the first invention of the present invention, the sizes of the Cu-plated particles and the Zn-plated particles after plating are each 0.
If it is less than 05 μm, it becomes difficult for the lubricant to enter. On the other hand, if the size of the Cu-plated particles and the Zn-plated particles after plating is more than 5 μm, the contained lubricant is likely to fall off. For this reason, Cu plated particles and Zn after plating
The size of the plated particles was 0.05 to 5 μm. Further, in the second invention of the present invention, the size of the voids in the surface layer portion formed by the brass-plated particles is appropriately in the range of 0.02 to 3 μm as the average interparticle distance of the openings. If this is less than 0.02 μm, it becomes difficult for the lubricant to enter, and if it exceeds 3 μm, the lubricant is likely to fall off, so this range was made.

The present invention will be described in more detail based on the following examples.

[0014]

【Example】

Example 1 As an example of the first invention of the present invention, a diffusion plating method in which a 1.2 mm diameter patenting-treated steel wire corresponding to SWRS82A is descaled, neutralized with alkali, and then Cu-plated and Zn-plated are sequentially applied for thermal diffusion. Brass plating was performed by. The Cu plating bath is a pyrophosphate Cu bath, and the Zn plating is a sulfuric acid Zn plating bath. Plating is Cu / Zn = 65/3
5, the total thickness was about 2 μm. The plating particles were changed according to the current density. Brass alloy diffusion is 50 in fluidized bed heat treatment furnace
The heat treatment was performed at 0 ° C. for about 10 seconds. About 0 after diffusion plating.
Wire drawing with a dry lubricant to a diameter of 9 mm, then wire drawing with a wet lubricant (sodium or calcium stearate) at a step reduction rate of 14% at a speed of 600 m / min, and a final wire diameter of 0.20 mm. The diameter.

For the evaluation of the wire drawing workability, the life of the die is judged, and for the ultrafine wire drawing having a diameter of 0.9 mm to 0.20 mm, 20 wire drawing dies are used, and any one of the final three stages is used. For wire drawing until one die is consumed, a drawing amount of 500 kg or more is ◎ (very good), 200 to 500 kg
Was evaluated as ◯ (good), and 200 kg or less was evaluated as x (impossible).

The size of the plated particles was measured by observing the sample immediately after plating with a scanning electron microscope. Table 1 shows the results of the size and wire drawability of the Cu and Zn particles of this example.

[0017]

[Table 1]

In Examples 1 to 6 of the present invention, the size of the Cu-plated particles and the size of the Zn-plated particles were both within the range of 0.05 to 5 μm, and the die life was also good because the lubricity during wire drawing was good. . In Comparative Examples 1 and 2, the size of the Zn-plated particles is less than 0.05 μm and exceeds 5 μm, so that in Comparative Examples 3 and 4, the size of the Cu-plated particles is 0.05.
Comparative Example 6 is less than 5 μm, and Comparative Example 5 is less than 0.05 μm.
Since it exceeds μm, lubricity becomes poor and die life is deteriorated.

Second Embodiment Next, a second embodiment of the present invention will be described. The plating and wire drawing conditions and the method for evaluating the wire drawing workability in this example are the same as those of the above-described first invention. The results of this example are summarized in Table 2. Table 2 shows the results of measuring the average inter-particle distance at the openings of the voids on the plated surface of the sample immediately after plating with a scanning electron microscope, and the drawing workability of the brass-plated steel wire corresponding to the sample. It is an evaluation result.

[0020]

[Table 2]

In Examples 1 and 2 of the present invention, the average interparticle distance at the opening of the void is in the range of 0.02 to 3 μm, and the die life is also good because the lubricity during wire drawing is good.
In Comparative Example 1, the average interparticle distance at the opening of the void is 0.02μ.
and the average interparticle distance of voids is 3 in Comparative Example 2.
Since it is more than μm, the lubricity becomes poor and the die life is deteriorated.

[0022]

As is apparent from the above embodiments, the present invention improves the storage capacity of the lubricant by controlling the size of the plating particles or the interval between the openings of the voids formed by the plating particles, and the ultrafine particles The wire drawing workability of the brass-plated steel wire in wire drawing is greatly improved, the die life is improved and the frequency of wire breakage is significantly reduced, and its industrial utility value is high.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a surface condition after plating according to the present invention, in which (a) a distribution condition of plated particles and (b)
It is the figure which expanded a part of (a) figure.

[Explanation of symbols] 1 ... plated particles 2 ... steel wire 3 ... voids 4 ... plated particles (large particle size) 5 ... plated particles (medium particle size) 6 ... plated particles (small particle size)

Claims (2)

[Claims] 1. A Cu, Z layer formed on a steel substrate by electroplating.
In brass diffusion plating in which n is sequentially deposited and then alloyed by thermal diffusion, the size of each of the Cu plated particles and the Zn plated particles before diffusion plating is 0.0
A brass-plated steel wire having an excellent drawability of 5 to 5 μm, which stores a lubricant during wire drawing in a void after thermal diffusion. 2. Cu, Z by electroplating on a steel substrate
In brass diffusion plating in which n is sequentially deposited and then alloyed by thermal diffusion, the size of the voids in the surface layer portion formed by the brass plating particles after diffusion plating is 0.02 as the average interparticle distance of the openings. A brass-plated steel wire having a wire drawing workability of 3 μm, which stores a lubricant during wire drawing in the void.