KR820000631B1 - Ternary alloy of cu-zn-co coated metall wire - Google Patents

Abstract

This invention is the steel wire coated by ternary alloy of Cu-Zn-Co contained cobalt of 0.1-50 wt %. The precipitation line of phase moves to the direction decreasing the component ratio of Cu to Zn by adding cobalt to brass like the equilibrium phase diagram of Cu-Zn-Co and the drawability of this alloy is raised by inhibiting precipitations of β phase due to that without decreasing the adherent force to rubber.

Description

Alloy coated steel wire (for tire cord)

1 is a state diagram of a CU-Zn-Co tertiary alloy.

2 is a schematic view of the adhesion test method of the metal striae.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to metal struts, and more particularly to metal struts excellent in freshness and salt water adhesion.

Conventionally, a striae obtained by plating brass containing 63.5 to 72% by weight of copper on the surface of steel wire has been used as a tire cord.

However, these structural members had the drawback of disconnection or plating during the drawing process, and in particular, the demand for safety and water resistance of steel tires has increased recently. Adhesiveness is important.

In general, the water adhesion of steel cord and rubber was often improved by reducing the proportion of copper in brass.

However, when the copper component is lowered to 63 wt% or less, the β phase of the body-centered cubic (b, c, c) structure is formed in the α phase of the face-centered cubic (f, c, c) structure. In the production of steel cords, the disconnection is frequently caused in the drawing process according to the plating process, causing a reduction in the life of the drawing die and a roughening of the plating surface.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems in the drawing process and to provide a metal wire structure having excellent adhesion to rubber at the same time.

The present invention provides a metal structure comprising a coating layer of a copper-zinc-cobalt ternary alloy covering a metal wire and the surface of the metal wire and containing cobalt (Co) in a proportion of 0.1 to 50% by weight.

The present invention has found that addition of cobalt as a third component to brass can improve freshness without lowering the adhesion to rubber.

That is, as can be seen from the Cu-Zn-Co three-way equilibrium diagram shown in FIG. 1, as Co is added to the Cu-Zn binary alloy, the β-phase precipitation line shifts to a lower direction of the Cu / Zn ratio and β It is thought that freshness improves because precipitation of a phase is suppressed.

As Co is added to Cu-Zn, the adhesion to rubber is higher than that of Cu-Zn alloys in all composition ranges under the strong corrosion environment such as in salt water conditions. The selectivity for is also relatively low.

This is presumably because the metal emulsion including cobalt formed at the interface between the Cu-Zn-Co alloy and the vulcanized rubber in contact with it is relatively stable physically and chemically.

The above-mentioned metal emulsion may be because the salt corrosion resistance of the Cu-Zn-Co tertiary alloy is superior to that of the Cu-Zn binary alloy.

In view of the freshness, the Cu-Zn-Co alloy used in the present invention contains the three-membered fraction in a proportion such that the β phase does not substantially precipitate (ie, substantially only the α phase).

In general, the Zn content of the ternary alloy used in the present invention is 10% by weight to 45% by weight, more preferably 20% by weight to 40% by weight.

In addition, the Co content of the ternary alloy used in the present invention is 0.1% by weight to 50% by weight, more preferably 0.5% by weight to 30% by weight or 1% by weight to 10% by weight.

Remainder is Cu.

Therefore, in order to manufacture the metal wire body of the present invention, the above-described Cu-Zn-Co tertiary alloy layer is coated on a steel wire or the like.

The coating means may be any one of chemical plating, electroplating, and hot-dip plating, and may be directly alloyed or multi-plated with each component to diffuse each component by heating to obtain a desired three-way alloy layer. It is irrelevant.

As a suitable method, Cu, Zn, and Co are plated separately in this order by a conventional electroplating method to obtain a multi-plated layer, followed by heating with sufficient temperature and time to obtain a Cu-Zn-Co insert alloy. Spread.

This heat diffusion is performed at 400-600 ° C. for 5 to 20 seconds.

The thickness of the finally plated ternary alloy layer is usually 1 to 2 mu.

The metal wire body of the present invention thus obtained can be used as fine wire for rubber reinforcement such as steel tire cord as it is drawn by a conventional drawing machine.

Generally, the freshness reduction rate is 85% to 97%.

Hereinafter, the Example of this invention is explained in full detail ([%] in an Example is a weight ratio).

Example 1

Cu, Zn, and Co were sequentially plated on the steel wire surface of wire diameter of 1.24mm by single plating to form three layers, followed by heat diffusion treatment at 550 ° C for 5-30 seconds for no and 1-no. , And the composition Cu-Zn-Co tertiary alloy plated layer represented by 9 was formed to a thickness of 1 mu.

The plated merchant wire thus obtained was successively drawn 19 times with a die by a continuous wet drawing machine to have a finishing (finishing) diameter of 0.25.

The dies used a commercially available alloy die, and the drawing speed was 700 m / min at the time when the last die passed.

In this drawing operation, the disconnection frequency and die life of the plated steel wire were determined to evaluate the freshness.

The measurement results are shown in the first table.

On the other hand, the criterion for evaluating the freshness is determined in consideration of both the disconnection frequency and the die life, and the disconnection frequency is measured for the number of disconnections between 1 ton of coated steel wire having a wire diameter of 0.25 mm, and the die life is the die 1 It was based on the fresh dose per piece.

"Right" in the table is 5 times / tons of disconnection times, the freshness per die is 600 kg or more, and "quantity" is 6-9 / tons of the disconnection times, and the freshness is 100-600 kg, "Fire" was defined as a case where the number of disconnections was 20 times / ton or more and the freshness was 100 kg or less.

On the other hand, the freshness and the die life are greatly influenced by the type of the die, the type of the fresh lubricant, and the type of the fresh machine.

As a comparative example, when the conventional Cu-Zn binary alloy plating was formed (no, 10, 11 in the first table), as in the case of 0, continuous drawing was conducted, and the freshness in the drawing process was examined.

The result is as stated in the 1st table | surface.

TABLE 1

Samples of no and 10, even though brass plating was uniformly plated in several plating furnaces, precipitated β phase by dividing Cu% = 63.

In other words, the plating results in several plating furnaces have a case where the β phase precipitates in some plating furnaces in a composition close to Cu% = 63 due to the change of plating conditions, and is mixed with the α phase.

In this case, the freshness was poor, and the freshness was also low in this sample.

Example 2

Cu, Zn, and Co were sequentially plated on the steel wires of wire diameters of 0.97mm, 1.10mm, 1.24mm and 1.60mm by electroplating to form a three-layer plating layer, followed by heat diffusion treatment and Cu-Zn-Co tertiary alloy plating layer. Formed.

These coated steel wires were sequentially drawn and stranded to prepare steel cords of Cu-Zn-Co three-way alloy plating of the structures and compositions shown in Table 2 below.

In order to investigate the adhesiveness of the thus obtained cord with rubber, the cord was buried in a rubber compound with a length of 12.7 mm in accordance with ASTMD-2229.

On the other hand, the adhesive rubber was immersed in a 5% sodium chloride solution for 30 seconds at room temperature (18-25 ℃) for the measurement of salt resistance adhesion (shown in Figure 2 experimental equipment). At the time of 4-5 days, the cord is drawn at a speed of 100 m / min to obtain a deposit (0-100%) of the rubber attached to the cord at this time, and the measurement results are shown in Table 3.

On the other hand, the used compound is a rubber compound for commercial tires of a different kind from the usual ones indicated by no, A-no, and G of the fifth table. The heating temperature, time, and vulcanization pressure at the time of vulcanization were respectively performed in accordance with the conditions of the number of rubber compounds.

In addition, the vulcanization of the present embodiment generally refers to the original vulcanization.

As a comparative example, the seawater adhesion resistance of the conventional Cu-Zn binary alloy plating codes of no, A-no, and G marks of Table 3 was investigated.

The measurement results are as in Table 3.

As can be seen from Examples 1 and 2, the metal-plated body plated with Cu-Zn-Co tertiary alloy has excellent freshness and excellent salt water-resistance adhesion compared with Cu-Zn binary alloy plating. .

[Table 2]

[Table 3]

The figures in the table indicate the rubber adhesion area (%) on the surface of tire cords subjected to tensile test after immersion in saline solution.

Example 3

Example 2 A tire cord of 1 × 5 (0.25) was produced from a steel plate coated with a Cu—Zn-Co alloy containing Cu at a ratio of 62.5% Co in Table 4 and Zn as a balance according to the process. It was.

The tire cord was tested in the same manner as in Example 2 with respect to the salt water adhesion, and the results are shown in Table 4 below.

TABLE 4

Note: 1. Adhesive to vulcanized rubber (after 1 day)

2. Force (kg / 12.7mm) when drawn at the rate of 100mm / min

As can be seen from Table 4, the Cu-Zn-Co alloy containing Co at a ratio of 0.1 to 20% by weight has a special effect in improving salt water adhesion.

Claims (1)

An alloy coated steel wire, which covers the surface of a metal wire and is formed of a coating layer of copper, zinc, and cobalt ternary alloy containing cobalt in a ratio of 0.1-50% by weight.

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