JPH02267257A - Method for diffusing multi-element alloy plating of steel wires - Google Patents

Abstract

PURPOSE:To easily obtain a multi-element alloy-plated steel wire having excellent drawability and stabilized quality characteristics at a high rate by plating a steel wire with metals in multiple layers and then passing the wire through a fluidized bed of sand kept at a high temp. to diffuse and alloy the plating metals. CONSTITUTION:A steel wire is plated with metals in multiple layers, and then the plated wire is continuously heated to diffuse and alloy the plating metals. In this case, the alloying is carried out by passing the multilayer plated wire through the fluidized bed of the sand having no reactivity to the alloy, without causing surface infiltration and kept at a high temp. When the plating layer consists of two layers of Cu and Zn and the diameter of the wire is controlled to >=0.7mm, the temp. of the fluidized bed is kept at 470-550 deg.C, and the dipping time is controlled to >=3sec and increased with an increase in the diameter. When the diameter is controlled to 0.7-2.0mm, the dipping time is preferably adjusted to 3.44-d-4.41dsec at the diameter of dmm. By this method, a multi-element alloy-plated steel wire having excellent drawability and stabilized quality characteristics such as a rubber adhesive property and cutting strength is obtained.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention mainly relates to a method for diffusing multi-component alloy plating onto wire for manufacturing rubber-reinforced metal cords. [Prior Art and Technical Problems] Automobile tires Steel cords for reinforcing rubber products, such as steel cords, are constructed by twisting together multiple small-diameter wires (strands), and are usually coated with multiple layers of plating at the wire stage to improve corrosion resistance and adhesion to rubber. Then, a method of alloying by thermal diffusion is adopted. Conventionally, this method has generally adopted an electrical heating method in which several current-carrying rolls are arranged on a line and a current is passed through the plating wire through the current-carrying rolls.

However, with this method, the diffusion temperature becomes unstable due to the unstable contact between the current-carrying roll and the wire and the fact that it is susceptible to the influence of the external environment such as air flow and temperature. Moreover, since the plating surface and the power supply roll come into contact with each other during diffusion, the plating surface is easily damaged and scratched. For this reason, it has been difficult to stably obtain a well-balanced quality of cords made of twisted wires, such as wire drawability, rubber adhesion, tensile strength, and cutting strength. Wire drawability is a parameter used in cold drawing with a die to activate the surface of the wire after multi-component plating, and is expressed by the degree of change in die hole dimensions.

In addition, in the above-mentioned electrical heating method, since a high voltage such as 4.5 V is applied, there is a risk of electric shock and there are problems in terms of work safety. If this is done, the vibration of the wire will increase, resulting in poor contact between the current-carrying roll and the wire, causing sparks. For this reason, even though it is possible to speed up the plating process up to the previous stage, the speed increase is limited in this plating diffusion process, making it impossible to speed up the entire line and hindering improvements in the productivity of plated wire. there were.

The present invention was devised to solve the above-mentioned problems, and its purpose is to provide a wire with excellent drawability,
Another object of the present invention is to provide a method for easily obtaining multi-component alloy plated steel wire at high speed and with excellent stability in quality characteristics such as rubber adhesion and cutting strength.

[Means to solve the problem]

In order to achieve the above object, the present inventor searched for various methods to replace the direct current heating method, and tried passing a multi-layer plated steel wire through solid particles heated and made fluid. In this method, although the heating temperature is stable, common sense would suggest that the plating layer would be abraded by solid particles, leading to removal of the plating layer and frequent surface scratches. However, in reality, it has been found that by setting the temperature conditions and immersion time within appropriate ranges, it is possible to successfully avoid the above-mentioned problems and achieve the intended purpose.

The present invention was devised from two researchers, and its basic characteristics are that multilayer plating is applied to a steel wire, and then the steel wire is continuously heated to diffuse and alloy the plated metal. The method involves passing a multilayer plated steel wire through a fluidized bed containing sand that is not reactive with the alloy and does not cause surface penetration, and maintained at a high temperature.

When the multiple plating layer is Cu-Zn211F plating and the steel wire diameter is 0.7 amφ to 2.0++aφ, the holding temperature of the fluidized bed is 470 to 550°C, the immersion time is 3 seconds or more, and the temperature is adjusted as the wire diameter increases. It is preferable to make it long.

As a fluidized bed, fluidizing air and combustion gas are ejected from radiant tubes to fluidize and heat the sand, or sand is placed on a rectifying plate and heated with a burner from above, while the sand is heated from above. Any method of feeding air from below the rectifying plate may be used.

In these cases, ZrO, A10, is typically used as the sand. In either case, the immersion time is the wire diameter d (mφ
), it is preferable to have a relationship of 3.44 d to 4.41 d.

The steel wire passed through the fluidized bed and subjected to multi-component alloy plating is subsequently cooled and surface cleaned by passing through a water bath. This treatment is preferably carried out using ultrasound.

The present invention is particularly suitable for alloying Cu-Zn plating for tire cords, as well as Cu-Zn-Ni, Cu-
It goes without saying that the present invention can also be applied to thermal diffusion treatment of Cu-based multi-component alloy plated steel wire such as Zn-Go.

The present invention will be specifically described below with reference to the accompanying drawings.

FIG. 1 shows the process of manufacturing plated wire to which the present invention is applied. 1 is a supply section, 2 is a heating/quenching section, 3 is a water cooling section, 5 is a pretreatment section, 6 is a first plating section, and 7 is a Washing section,
8 is a second plating section, 9 is a water washing section, and 10 is a hot water washing section.

These are the same as known lines and processes, and the wire drawn to a predetermined diameter is heated and hardened by passing from the supply section 1 through the heating section 2, and then cooled.
The first plating portion 6 is chemically treated with cl+NaOH, etc.
For example, the substrate is plated with Cu, and the second plating portion 8 is plated with, for example, Zn, so that multilayer plating is continuously applied to the base surface.

In the present invention, a fluidized bed diffusion furnace 11 is provided in the line after the plating process, as shown in FIGS.
A water washing section 12. A hot water washing section 15 and a drying section 16 are provided,
A multilayer plating wire W is passed through these continuously and finally wound up at a winding section 17.

As a result, the multilayer plated wire W is heated by passing through the fluidized bed, the plated layer is alloyed by thermal diffusion, and is cooled and surface cleaned by passing through the water washing section 12, and then the hot water washing section 15, it passes through a drying section 16, where it is washed and dried.

Figures 2 and 3 show a fluidized bed diffusion furnace 11 used in the present invention.
An example is shown in which a large number of radiant tubes 111 are arranged at predetermined intervals in a tunnel-shaped furnace body 110 filled with fine-grained sand 114, and each radiant tube 1
A combustion burner 112 for burning a hydrocarbon gas, for example, butane, and a fluidizing air supply section 113 are provided in a part of the header 11 or a header in which these gases are assembled. gush,
This allows the sand layer to flow due to aeration while being maintained at a high temperature.

4 and 5 show another example of the fluidized bed diffusion furnace 11, in which the interior of the furnace body 110 is partitioned by a baffle plate 116 into an upper chamber 117a and a lower chamber 117b. The upper chamber 117a accommodates sand 114, and
It is heated by a heating burner 118 provided on the ceiling or side wall, and a flow air introduction pipe 119 is arranged in the lower chamber 117b.
It is ejected into the sand layer through countless meshes that exist in the 16th century.

Incidentally, the furnace body 110 is provided with a recovery device 121 for returning the washed sand to the upper chamber 117a.

The sand used is a material that has no chemical reactivity with the plating or alloy and does not cause surface penetration, typical examples of which include ZrO2 and AIO3.

In either fluidized bed structure, the multilayer plating wire W is connected to guides 1 disposed on the outlet side and the inlet side of the furnace body 110.
24, 125 through a sand layer maintained at a high temperature. In this case, the plating in the previous step should be performed under conditions such that the plating composition (Cu %) is 62 to 67%, the plating amount is 3 to 6 g/kg, and the diffusion conditions are as follows.

When the fluidized bed diffusion method according to the present invention is adopted, when the diameter of the multilayer plated wire is within the usual range, that is, 0.7 mmφ or more, the temperature of the fluidized bed should be in the range of 470 to 550°C, and the holding time (immersion time) should be at least 3 seconds. , the upper limit is preferably 3.44 to 3.44 depending on the increase in wire diameter (d).
4.41 should be set to d. For example, when the multilayer plated wire is 0.93 nm + φ, the holding time is 3 to 4.5 seconds using the radiant tube method, which is the same < 1.
In case of 35mm+φ, 4 to 6 seconds, same < 1.65■
In the case of φ, the optimum condition is 5.5 to 7.5 seconds. If the temperature is higher than this and the temperature is maintained for a long time, the dezincing of the surface will be significant and the adhesion to rubber will deteriorate. On the other hand, at low temperatures and short times, the β phase increases, causing problems in mechanical properties such as wire drawability. Furthermore, under conditions of high temperature and short-time holding, or low temperature and long-time holding, the plating and heat treatment conditions are out of the appropriate range, making in-line diffusion treatment difficult.

The above diffusion conditions were discovered by the inventor through experiments,
Taking wire diameter 1, 35mm+φ as an example, the relationship between diffusion conditions and multi-component alloy plating wire characteristics is shown in the following 1st example.
It is as shown in the table.

Table 1 From this Table 1, it can be seen that the above temperature conditions and holding times are essential conditions.

The conditions on the fluidized bed side to achieve the above diffusion conditions are, for example, 240 to 76 ONrn'/h, pressure 1 when the fluidized bed is a radiant tube type.
000-1500mmH2O, combustion gas (for butane) conditions, flow rate 190-650 Nm/h
, pressure 20~1301mm! (20. Combustion gas/(fluidizing air + combustion gas) may be set appropriately from the range of 20 to 70%. In addition, in the case of the baffle plate method, the fluidizing air condition is 1200 to 180 ON m'/h , pressure 3000-3500mmH, 0, combustion gas (in case of butane) flow rate 700-1100N rrl
' / ) i, pressure 650 to 750 mmH2O, and mixing ratio (gas:air) 1:(12 to 15).

〔Example〕

Next, examples of the present invention will be shown.

According to the present invention, copper-zinc double layer plated wire for steel tire cord (wire diameter 0.93, 1,35, 1.65 m+n
φ) was subjected to thermal diffusion treatment using a radiant tube type fluidized bed shown in FIGS. 2 and 3.

The conditions and results are shown in Table 2 in comparison with those using the electrical heating method. In addition, Table 3 shows the properties of a steel cord made using the cold drawn wire of the obtained multi-plated wire in comparison with those made using the electrical heating method. In Table 3, 0.175 is the wire drawn from 0.93111 mmφ, and similarly, 0.28 is the wire drawn from 1.35 mmφ, 0.
38 is a wire drawn from a multi-component alloy plated wire with a diameter of 1.65 mm.

As is clear from Table 3, when the diffusion method according to the present invention is adopted, there is little variation in the β phase, stable reactivity with rubber, good adhesive properties, and good wire drawability. I understand that. Therefore, it can also be seen that the steel cord obtained by twisting plated wires also has good characteristics that are well-balanced and have little variation.

Furthermore, the present invention allows stable production even in the range of wire speeds of 60 m/min or higher, where stable production is impossible with energization diffusion.

〔Effect of the invention〕

According to the present invention as described above, in the method of applying multilayer plating to ms and then continuously heating the steel wire to diffuse and alloy the plated metal, sand that is not reactive with the alloy and does not cause surface penetration. Since the alloy is alloyed by passing multilayer plated steel wire through a fluidized bed kept at high temperature, the diffusion temperature can be kept stable and constant, and the heat transfer coefficient is approximately 1000 kcal/℃・m・hr and high thermal efficiency, the value of the plating β phase is stable, there are few surface scratches, and it is possible to obtain steel wires and cords with excellent stability in quality characteristics such as wire drawability, rubber adhesion, and cutting load. .

In addition, due to its high thermal efficiency, it requires a smaller diffusion space than the single current heating type, and there is no spark problem like the current heating type, so it can handle higher speeds and eliminates problems such as electric shock. Because of this, excellent effects such as improved safety can be obtained.

[Brief explanation of drawings]

Fig. 1 is a flow sheet illustrating a multi-component alloy plated wire manufacturing line to which the present invention is applied, Fig. 1a is a schematic side view of the diffusion treatment process, and Fig. 2 is a plan view showing an example of a fluidized bed used in carrying out the present invention. 3 is a longitudinal sectional view thereof, FIG. 4 is a longitudinal sectional side view showing another example of the fluidized bed, and FIG. 5 is a longitudinal sectional front view thereof. 6.First plating section, 8.Second plating section, 11.Fluidized bed diffusion furnace, 12.Water washing section

Claims (7)

[Claims] (1) In a method in which multilayer plating is applied to a steel wire and then the steel wire is continuously heated to diffuse and alloy the plated metal, sand that is not reactive with the alloy and does not cause surface penetration is maintained at a high temperature. A method for diffusing multi-alloy plating on steel wires, which comprises alloying the multi-layer plated steel wire by passing it through a fluidized bed. (2) When the multilayer plating layer is Cu-Zn double layer plating and the steel wire diameter is 0.7 mmφ or more, the holding temperature of the fluidized bed is set to 47
The method for diffusing multi-component alloy plating on steel wires according to claim 1, which is carried out at 0 to 550°C for a dipping time of 3 seconds or more and lengthening as the wire diameter increases. (3) For wire diameter dmmφ, immersion time is 3.44d~
4. A diffusion method for multi-component alloy plating of steel wires according to claim 2, wherein the diffusion time is 41 d seconds. (4) The method for diffusing multi-component alloy plating on steel wires according to claim 2 or 3, wherein the wire diameter range is from 0.7 to 2.0 mmφ. (5) Claim 1 uses a type of fluidized bed in which both fluidizing air and combustion gas are ejected into the sand layer.
A method for diffusing multi-component alloy plating on steel wires according to any one of items 1 to 4. (6) Steel wires according to any one of claims 1 to 4, in which the fluidized bed is of a type in which fluidizing air is ejected from below into the sand layer and the sand is heated from outside the sand layer. Diffusion method for multi-component alloy plating. (7) The method for diffusing multi-alloy plating on steel wires according to any one of claims 1 to 6, wherein after passing through a fluidized bed, cooling and surface cleaning are performed by superimposing ultrasonic waves.