TW201907026A - Molten aluminum-plated steel wire applicable to wiring harness of a vehicle and having excellent torsion characteristics - Google Patents

Abstract

The present invention relates to a molten aluminum-plated steel wire which has a plating layer on the surface of a steel wire having a diameter of 0.1 to 0.4 mm and is prepared by being subjected to wire drawing. The molten aluminum-plated steel wire is characterized in that the elongation at break is 5 to 30% from the melting. The ratio of the average diameter of each 100 mm long steel wire of the molten aluminum-plated steel wire having the plating layer being removed to the minimum diameter of the steel wire satisfies the mathematical formula: [minimum diameter / average diameter] is greater than or equal to [1-(elongation at break (%) / 100)].

Description

 Molten aluminum plated steel wire  

This invention relates to a molten aluminum plated steel wire. More specifically, the present invention relates to a molten aluminum plated steel wire which is excellent in torsional properties and which can be suitably used, for example, in a wire harness for automobiles, and a method for producing the same.

In the present specification, the "melting aluminum plating" of the molten aluminum-plated steel line indicates the type of aluminum plating, and the molten aluminum-plated steel line means that the steel wire is immersed in the molten aluminum plating bath, and the molten aluminum plating bath is continuously continuous. The steel wire is pulled up, whereby the steel wire of aluminum plating is applied. Further, the torsion type means a property that it is difficult to break when the steel wire is twisted.

In a wire used for a wire harness of a car or the like, a molten aluminum plated steel wire to which a molten aluminum plate is applied to a steel core wire is used in a plurality of strips of seven or nine, and a stranded wire is processed by using the molten aluminum plated steel wire. The resulting stranded wire. In the manufacture of the stranded wire, the molten aluminum-plated steel wire constituting the stranded wire is twisted, and since the molten aluminum-plated steel wire is broken when the twist of the molten aluminum-plated steel wire is large, the molten aluminum-plated steel wire is required to be avoided. An indicator of torsional fracture.

As a molten aluminum-plated steel wire which has improved resistance to torsion, a molten aluminum-plated steel wire has been proposed (refer to Patent Application No. 1 to 2 of Patent Document 1), which is not subjected to wire drawing after molten aluminum plating, and A molten aluminum-plated steel wire having a steel core wire having a diameter of 0.05 to 0.50 mm in the core material, and uniformizing the adhesion amount of the molten aluminum plating to an average diameter D _A (mm) and a minimum diameter D _MIN (mm) in the longitudinal direction thereof are satisfied. Mathematical formula (I), (D _{A -} D _MIN ) / D _A ≦ 0.10 (1).

In the molten aluminum-plated steel wire, it is required to satisfy the mathematical expression (I) in order to ensure the torsional torsion resistance of the molten aluminum-plated steel wire per 100 mm length to 50 times or more (refer to paragraph [Patent Document 1] [ 0022]).

 [Prior patent documents]    [Patent Literature]  

[Patent Document 1] JP-A-2014-185355

In the molten aluminum-plated steel wire, a hard steel wire is used as the steel wire (see paragraph [0034] of Patent Document 1), and the elongation of the hard steel wire is approximately 5% or less, and the hard steel wire is used as the steel wire. When the wire drawing process is applied to the molten aluminum-plated steel wire of the steel wire, the torsional property is remarkably lowered, so that the molten aluminum-plated steel wire is used in a state where the wire drawing process is not applied (refer to paragraph [0023] of Patent Document 1] ).

However, in the case of fracture of the stainless steel wire or the like of the Worthite iron system, the elongation is 30% or more, and the steel wire which is more elongated than the hard steel wire is applied with molten aluminum plating, even if the mathematical formula (I) is not satisfied. The relationship shown is also that the number of fracture torsion per 100 mm length of the molten aluminum plated steel wire is many hundreds of times, and the molten aluminum plated steel wire has a certain degree of torsion even if it is subjected to wire drawing.

In recent years, steel wire used for stranding processing uses a steel wire which is more elongated than a hard steel wire, and it is desired to develop a molten aluminum-plated steel wire which is subjected to wire drawing processing which is excellent in torsion property at the time of twist wire processing.

The present invention has been made in view of the above-described conventional art, and an object thereof is to provide a molten aluminum-plated steel wire which is excellent in torsion property when a stranding process is applied, and a method for producing the same.

The invention is related to

(1) A molten aluminum-plated steel wire is a molten aluminum-plated steel wire having a plating layer on the surface of a steel wire having a diameter of 0.1 to 0.4 mm, and the elongation at break is 5 to 30%, from the molten aluminum-plated steel. The ratio of the average diameter per 100 mm length of the steel wire from which the wire has been removed to the minimum diameter of the steel wire satisfies the formula (I): [minimum diameter / average diameter] ≧ [1 - elongation at break (%) ) /100)] (I).

(2) A method for producing a molten aluminum-plated steel wire, which is a method for producing a molten aluminum-plated steel wire having a plating layer on a surface of a steel wire having a diameter of 0.1 to 0.4 mm, from which the molten aluminum-plated steel wire has been removed The ratio of the average diameter per 100 mm length of the steel wire of the electroplated layer to the minimum diameter of the steel wire satisfies the formula (I): [minimum diameter / average diameter] ≧ [1 (elongation at break (%) / 100) ] (I)

The molten aluminum-plated steel wire is subjected to wire drawing in such a manner that the elongation at the time of fracture of the molten aluminum-plated steel wire is 5 to 30%.

According to the present invention, there is provided a molten aluminum-plated steel wire excellent in torsion property when a stranding process is applied, and a method for producing the same.

1‧‧‧Fused aluminum plating bath

2‧‧‧Steel wire

3‧‧‧Fused aluminum plated steel wire

4‧‧‧ delivery device

5‧‧‧ plating bath

6‧‧‧ bath surface of molten aluminum plating bath

7‧‧‧Stabilized components

8‧‧‧ nozzle

8a‧‧‧ front end of the nozzle

9‧‧‧Inert gas supply device

10‧‧‧Pipe

11‧‧‧Cooling device

12‧‧‧Winding device

13‧‧‧Test line

14a‧‧‧ chuck

14b‧‧‧ chuck

15‧‧‧ test bench

16‧‧‧Trolley

17‧‧‧Code

Fig. 1 is a schematic explanatory view showing an embodiment of a molten aluminum-plated steel wire of the present invention.

Fig. 2 is a schematic cross-sectional view showing a boundary portion between a steel wire and a bath surface of a molten aluminum plating bath when a steel wire is drawn from a molten aluminum plating bath in the production of the molten aluminum-plated steel wire of the present invention.

Fig. 3 is a schematic explanatory view showing a torsion test apparatus for a molten aluminum-plated steel wire used in each of the examples and comparative examples of the present invention.

Hereinafter, an embodiment of a method for producing a molten aluminum-plated steel wire according to the present invention will be described based on the drawings, but the present invention is not limited to this embodiment.

Fig. 1 is a schematic explanatory view showing an embodiment of a method for producing a molten aluminum-plated steel wire according to the present invention. Fig. 2 is a schematic cross-sectional view showing a boundary portion between a steel wire and a bath surface of a molten aluminum plating bath when a steel wire is pulled from a molten aluminum plating bath in the production of the molten aluminum-plated steel wire of the present invention.

In the present invention, after the steel wire 2 is immersed in the molten aluminum plating bath 1, the molten aluminum plating bath 1 continuously pulls up the molten aluminum plated steel wire 3, whereby the molten aluminum plated steel wire 3 can be produced.

Examples of the steel material constituting the steel wire 2 include stainless steel and mild steel, but the present invention is not limited to this example.

The stainless steel is an alloy steel containing 10% by mass or more of chromium (Cr). For example, stainless steel, ferrite-based stainless steel, and 麻田散铁-based stainless steel, which are defined by JIS G4309, are exemplified, but the present invention is not limited to this example. Specific examples of the stainless steel include stainless steel which is stable with a general Worthite iron phase such as SUS301 or SUS304, and a stable Worstian iron-based stainless steel such as SUS305, SUS310, and SUS316; SUS405, SUS410, SUS429, SUS430, and SUS434. SUS 436, SUS 444, SUS 447, etc., and the rust-iron-based stainless steels of the SUS, SUS, SUS, SUS, SUS, SUS, and SUS440, and the SUS200 series of chromium-nickel-manganese Stainless steel or the like, but the present invention is not limited to this example only.

The mild steel series is a steel material specified by the iron wire of JIS G3532, a steel material specified by the specification of the soft steel wire of JIS G3505, etc., but the present invention is not limited to this example only.

In the steel wire 2, stainless steel is preferable from the viewpoint of improving the tensile strength of the molten aluminum plated steel wire 3.

The diameter of the steel wire 2 before the wire drawing process is not particularly limited, and is preferably adjusted as appropriate in accordance with the use of the molten aluminum plated steel wire 3. For example, in the case where the molten aluminum plated steel wire 3 is used for a wire harness of an automobile or the like, the diameter of the steel wire 2 before the wire drawing process is generally preferably about 0.2 to 0.4 mm.

In the first drawing, the steel wire 2 is sent out from the feeding device 4 of the steel wire 2, and is continuously conveyed in the direction of the arrow A, and then immersed in the molten aluminum plating bath 1 in the plating bath 5. The molten aluminum-plated steel to which the molten aluminum plating bath 1 adheres to the surface of the steel wire 2 can be obtained by pulling up the steel wire 2 immersed in the molten aluminum plating bath 1 from the bath surface 6 of the molten aluminum plating bath 1. Line 3.

Since the plating film (electroplating layer) to which the aluminum plating bath 1 is adhered is formed on the surface of the molten aluminum plated steel wire 3 in this manner, the molten aluminum plated steel wire 3 is excellent in adhesion to the aluminum wire, and is in tensile strength. And the aging stability of the resistor is also excellent.

In the molten aluminum plating bath 1, aluminum may be used alone, and other elements may be contained in a range not inhibiting the object of the present invention as needed.

As other elements, for example, nickel, chromium, zinc, bismuth, copper, iron, or the like is exemplified, but the present invention is not limited to this example only. When aluminum is contained in these other elements, the mechanical strength of the plating film can be improved, and further, the tensile strength of the molten aluminum-plated steel wire 3 can be improved. In the other elements, the generation of a brittle iron-aluminum alloy layer between the iron contained in the steel wire and the aluminum contained in the plating film is suppressed depending on the type of the steel wire to improve the mechanical mechanism of the plating film. The strength is excellent, and the viewpoint of efficiently melting the steel wire 2 by lowering the melting point of the molten aluminum plating bath 1 is preferable.

The lower limit of the content ratio of the other elements in the plating film is 0% by mass, but from the viewpoint of sufficiently exhibiting the properties of the other elements, it is preferably 0.3% by mass or more, more preferably 0.5% by mass or more. It is preferably 1% by mass or more, and is preferably 50% by mass or less, more preferably 20% by mass or less, from the viewpoint of suppressing potential difference corrosion caused by contact with the aluminum wire used in the production of the strand. The best quality below is %.

In the molten aluminum plating bath 1, elements such as Fe, Cr, Ni, Zn, and Cu may be inevitably mixed.

When the steel wire 2 is pulled up from the molten aluminum plating bath 1, as shown in Fig. 2, the stabilizing member 7 is brought into contact with the steel wire 2 at the boundary portion between the steel wire 2 and the bath surface 6 of the molten aluminum plating bath 1. good.

As the stabilizing member 7, for example, a corner bar made of stainless steel whose surface is wound with a heat-resistant cloth material is exemplified. The heat-resistant fabric wound around the stabilizing member 7 preferably contacts the new surface (new surface) of the stabilizing member 7 with the steel wire 2 from the viewpoint of suppressing adhesion of the molten aluminum block to the surface of the molten aluminum-plated steel wire 3. In the new surface (new surface) of the stabilizing member 7, for example, when the stabilizing member 7 is brought into contact with the steel wire 2 while the stabilizing member 7 is wound with the heat-resistant cloth, the steel wire 2 is pulled up, in order The heat-resistant cloth is wound, whereby it can be formed.

It is preferable that the stabilizing member 7 is in contact with both the bath surface 6 of the molten aluminum plating bath 1 and the steel wire 2 at the same time. When the stabilization member 7 and the bath surface 6 of the molten aluminum plating bath 1 and the steel wire 2 are simultaneously contacted in this manner, the pulsation of the bath surface 6 of the molten aluminum plating bath 1 is suppressed, and the steel wire 2 is stabilized. When the state in which the chemical member 7 is in contact is lifted, the steel wire 2 is suppressed from being slightly vibrated, and further, the plating film of the molten aluminum plating bath 1 can be uniformly formed on the surface of the steel wire 2. When the stabilizing member 7 is brought into contact with the steel wire 2, from the viewpoint of suppressing the slight vibration of the steel wire 2, the steel wire 2 may be lightly pressed against the steel wire 2 as needed, and the steel wire 2 may be lightly pressed against the stabilizing member 7 as needed. .

In the embodiment shown in Fig. 1, a nozzle 8 for injecting an inert gas into a boundary portion between the steel wire 2 and the bath surface 6 of the molten aluminum plating bath 1 is provided. The inert gas system can be supplied to the nozzle 8 from the inert gas supply device 9 via the pipe 10, for example. In order to adjust the flow rate of the inert gas in the inert gas supply device 9 or the pipe 10, for example, a flow rate control device (not shown) such as a valve may be provided.

In the present invention, since the distance from the steel wire 2 to the front end 8a of the nozzle 8 (the shortest distance) and the temperature of the inert gas discharged from the front end 8a of the nozzle 8 are appropriately controlled, and the inner diameter of the front end of the nozzle 8 is appropriately controlled Since the volume flow rate of the inert gas discharged from the nozzle 8 is high, the molten aluminum-plated steel wire 3 having a uniform wire diameter and hardly adhering the molten aluminum block to the surface can be efficiently produced.

The inner diameter of the front end of the nozzle 8 is such that the inert gas discharged from the front end 8a of the nozzle 8 is accurately injected from the boundary portion between the steel wire 2 and the bath surface 6 of the molten aluminum plating bath 1, so that the melting can be efficiently performed. The viewpoint of the aluminum-plated steel wire 3 is preferably 1 mm or more, more preferably 2 mm or more, and from the viewpoint of obtaining a molten aluminum-plated steel wire 3 having a uniform wire diameter and hardly adhering the molten aluminum block to the surface, it is 15 mm or less. Good, better than 10mm, best under 5mm.

The distance (the shortest distance) from the steel wire 2 to the front end 8a of the nozzle 8 is obtained from the viewpoint of avoiding contact with the steel wire 2 and efficiently manufacturing the molten aluminum-plated steel wire 3, preferably 1 mm or more. The wire diameter is a viewpoint of a molten aluminum-plated steel wire 3 in which the molten aluminum block hardly adheres to the surface, and is preferably 50 mm or less, preferably 40 mm or less, more preferably 30 mm or less, and most preferably 10 mm or less.

Inert gas means a gas that is inert to molten aluminum. Examples of the inert gas include nitrogen gas, argon gas, helium gas, and the like, but the present invention is not limited to this example only. Among the inert gases, nitrogen is preferred. The inert gas may contain, for example, oxygen, carbon dioxide or the like within a range not inhibiting the object of the present invention.

The volume flow rate of the inert gas discharged from the tip end 8a of the nozzle 8 is preferably 2 L (liter) / min or more from the viewpoint of obtaining a molten aluminum-plated steel wire 3 having a uniform wire diameter and a molten aluminum block hardly adhering to the surface. It is preferably 5 L/min or more, and is preferably 10 L/min or more, and is preferably 200 L/min or less from the viewpoint of suppressing the scattering of the molten aluminum block by the molten aluminum plating bath 1 and adhering to the surface of the molten aluminum-plated steel wire 3. It is preferably 150 L/min or less, and is preferably 100 L/min or less.

The temperature of the inert gas discharged from the tip end 8a of the nozzle 8 is preferably 200 ° C or higher from the viewpoint of obtaining a molten aluminum-plated steel wire 3 having a uniform wire diameter and hardly adhering the molten aluminum block to the surface, and is preferably 300 ° C or higher. Preferably, it is preferably 400 ° C or higher, because the thermal efficiency is lowered when it is too high, so it is preferably 800 ° C or less, preferably 780 ° C or less, and preferably 750 ° C or less. The temperature of the inert gas discharged from the front end 8a of the nozzle 8 is a value measured by inserting a thermocouple for temperature measurement into an inert gas discharged from the front end 8a of the nozzle 8 at the front end 8a of the nozzle 8.

The pulling speed at which the molten aluminum-plated steel wire 3 is pulled up from the bath surface 6 of the molten aluminum plating bath 1 is not particularly limited because the surface of the molten aluminum-plated steel wire 3 can be adjusted by appropriately adjusting the pulling speed. The average thickness of the molten aluminum plating film present is appropriately adjusted in accordance with the average thickness of the molten aluminum plating film.

The process of cooling the molten aluminum-plated steel wire 3 is cooled, and in order to efficiently solidify the aluminum plating film formed on the surface, as shown in Fig. 1, a cooling device 11 may be disposed as needed. In the cooling device 11, the molten aluminum-plated steel wire 3 can be cooled by spraying a mist of a gas, a liquid, or the like on the molten aluminum-plated steel wire 3.

The molten aluminum plated steel wire 3 manufactured in the above manner can be recovered, for example, by the winding device 12 or the like.

The average thickness of the molten aluminum plating film present on the surface of the molten aluminum-plated steel wire 3 is from the viewpoint of suppressing the exposure of the steel wire 2 of the substrate during stranding, caulking, and the like, and improving the mechanical strength per unit wire diameter. It is preferably about 5 to 10 μm.

The plating layer may be formed between the steel wire 2 of the molten aluminum-plated steel wire 3 and the molten aluminum plating film as an intermediate layer. Examples of the metal constituting the plating layer include zinc, nickel, chromium, an alloy of these metals, and the like, but the present invention is not limited to this example only. Further, the molten aluminum plating film may be formed of only one layer, or a plurality of plating films made of the same or different metals may be formed.

The molten aluminum-plated steel wire 3 obtained as described above can be subjected to wire drawing processing using, for example, a mold to have a wire diameter of 0.1 to 0.4 mm.

Further, the elongation at the time of the fracture of the molten aluminum-plated steel wire 3 is 5% or more from the viewpoint of improving the torsional properties of the molten aluminum-plated steel wire 3 after the wire drawing, and is preferably 10% or more, and is 15% or more. Preferably, it is 30% or less from the viewpoint of improving the torsional properties of the molten aluminum-plated steel wire 3 after the wire drawing process.

The elongation at the time of the fracture of the molten aluminum-plated steel wire 3 after the wire drawing is adjusted according to the "metal material tensile test method" prescribed in JIS Z2241, the original puncture distance is adjusted to 100 ± 1 mm, and the grip pitch is set to 150 mm. The value at the time of measurement of the test piece No. 9A described in the column "The type of the linear or rod-shaped test piece used for the wire or the rod having a diameter or a side length of less than 4 mm" in JIS Z2241 is used.

In the present invention, the average diameter per 100 mm length of the steel wire from which the electroplated layer of the molten aluminum-plated steel wire after the wire drawing process is removed and the minimum diameter of the steel wire are measured.

The method of removing the plating layer from the molten aluminum plated steel wire after the wire drawing process is not particularly limited. For example, the molten aluminum plated steel wire is immersed in hydrochloric acid having a liquid temperature of 5 to 10% at a normal temperature for about 10 minutes. The plating layer can be removed from the molten aluminum plated steel wire.

The present inventors measured the wire diameter of the molten aluminum-plated stainless steel wire after plating molten aluminum, and investigated the unevenness of the adhesion amount of the plating layer, and applied the molten aluminum-plated stainless steel wire to the molten aluminum-plated stainless steel wire. After the wire drawing process and measuring the elongation caused by the tensile test of the molten aluminum-plated stainless steel wire which has been applied by the wire drawing, the torsion test is performed, thereby investigating the elongation of the molten aluminum-plated stainless steel wire after the wire drawing process. And the influence of the unevenness of the adhesion amount of the plating layer on the torsion property. As a result, it was found that the torsional properties of the molten aluminum-plated stainless steel wire were substantially as follows.

(1) Under the condition that the adhesion amount of the plating layer is the same, the unevenness of the adhesion amount of the plating layer tends to be large, and the torsional property tends to decrease.

(2) The smaller the elongation of the molten aluminum-plated stainless steel wire after the wire drawing process, the more the twisting property tends to decrease.

The thickness of the electroplated layer of the molten aluminum-plated stainless steel wire is completely uniform, because the minimum diameter of the stainless steel wire of the molten aluminum-plated stainless steel wire becomes the same as the average diameter of the stainless steel wire, so the melting is reversed. When aluminum-plated stainless steel wire is used, since the molten aluminum-plated stainless steel wire can be uniformly twisted as a whole, the number of twists is maximized.

However, when manufacturing a molten aluminum-plated stainless steel wire, it is difficult to make the thickness of the plating layer completely uniform. By applying a wire drawing process to a molten aluminum-plated stainless steel wire having a uniform thickness of the plating layer, a molten aluminum-plated stainless steel wire having a uniform outer diameter to which wire drawing is applied is produced because of the area of the stainless steel wire and the plating layer. The ratio is unchanged before and after the wire drawing process, so the cross-sectional area of the stainless steel wire after the wire drawing process is relatively smaller than the cross-sectional area of the stainless steel wire before the wire drawing process, and plating on the molten aluminum plated stainless steel wire. In the portion where the thickness of the layer is large, the wire diameter of the cross-sectional area of the stainless steel wire after the wire drawing is relatively small becomes small.

Therefore, in the case where the molten aluminum-plated stainless steel wire which is not uniform in thickness of the plating layer is twisted, the molten aluminum-plated stainless steel wire which has been twisted is broken at the portion where the wire diameter of the stainless steel wire is the smallest.

The smallest diameter of the molten aluminum-plated stainless steel wire is the thickest portion of the plating layer, but the plating layer is formed of aluminum, and since the aluminum strength is lower than that of the stainless steel, there is almost no contribution to the improvement of the torsion property.

The inventors estimated the number of twists required to apply the stranding process to the molten aluminum-plated stainless steel wire from the processing conditions of the strand.

The standard stranding pitch of the strands of the molten aluminum-plated stainless steel wire is set to be 20 to 40 times the wire diameter of the molten aluminum-plated stainless steel wire. That is, on the molten aluminum-plated stainless steel wire, the molten aluminum-plated stainless steel wire is twisted once at this pitch. In order to prevent the fracture caused by the twisting of the stranded wire of the molten aluminum-plated stainless steel wire, it is considered that the state in which the twist is applied within 10 times of the wire diameter of the molten aluminum-plated stainless steel wire is not broken. There is no problem in actual use, so it is considered that the qualification criteria are met.

Therefore, for example, in the case where the wire diameter of the molten aluminum-plated stainless steel wire is 0.2 mm, even if the molten aluminum-plated stainless steel wire is twisted more than 50 times per 100 mm length, the steel wire does not break, the qualified standard is satisfied, and the molten metal is melted. When the wire diameter of the aluminum-plated stainless steel wire is 0.32 mm, the steel wire does not break even if the molten aluminum-plated stainless steel wire is twisted 32 times or more per 100 mm length, and the qualified standard is satisfied.

Based on the acceptance criteria, the relationship between the unevenness of the adhesion amount of the plating layer of the molten aluminum-plated stainless steel wire and the elongation at the time of the fracture of the molten aluminum-plated stainless steel wire after the wire drawing was examined.

As a result, the relationship between the minimum wire diameter/average wire diameter of the stainless steel wire after the wire-plated layer of the molten aluminum-plated stainless steel wire after the wire drawing process and the elongation of the molten aluminum-plated stainless steel wire satisfy the mathematical formula (I) When [Minimum Diameter/Average Diameter] ≧ [1-(Elongation at Break (%)/100)] (I)

It is known that the molten aluminum-plated stainless steel wire after the twisted wire drawing is 10 times of the wire diameter of the molten aluminum-plated stainless steel wire does not break.

Therefore, in the present invention, the elongation at break is 5 to 30%, and it is considered that the ratio of the average diameter per 100 mm of the steel wire from which the electroplated steel layer has been removed to the minimum diameter of the steel wire satisfies the ratio The molten aluminum-plated steel wire of the mathematical formula (I) is excellent in torsional properties.

The molten aluminum-plated steel wire of the present invention can be suitably used, for example, in a wire harness of an automobile or the like.

[Examples]

Next, the present invention will be described in more detail based on examples, but the present invention is not limited to only this embodiment.

First to eighth embodiments and first to ninth comparative examples

According to the embodiment shown in Fig. 1, a molten aluminum plated steel wire is produced.

As the steel wire, a stainless steel wire having a wire diameter before plating shown in Table 1 and having SUS304 having elongation at the time of fracture shown in Table 1 was used. After preheating the stainless steel wire in nitrogen, it is sent to a molten aluminum plating bath, and then pulled up vertically from the bath surface, and the heat-resistant cloth and the bend formed around the steel wire are pulled in the lifting portion of the self-bath surface. The lunar surface contacts and sprays heated nitrogen gas to the contact portion, whereby the amount of plating is stabilized. Further, the wire feed speed was set to 300 m/min.

The wire diameter of the molten aluminum plated steel wire obtained in the above manner was measured. The wire diameter of the molten aluminum-plated steel wire is an optical outer diameter measuring device [(Company) KEYENCE, model: LS-7000], and two of the diameter cross sections of the steel wire are spaced at 0.08 mm in the longitudinal direction. The direction is measured 10 times, and the average value is taken as the wire diameter. The wire diameter of the molten aluminum plated steel wire is described in the column of "wire diameter after plating" in the first table.

Then, the molten aluminum-plated steel wire is passed through a mold, and the molten aluminum-plated steel wire is subjected to wire drawing so as to have a wire diameter as shown in the column of "wire diameter after wire drawing" of the first table.

A part (length: 100 mm) of the molten aluminum-plated steel wire to which the wire drawing was applied was cut out, and the molten aluminum-plated steel wire was immersed in hydrochloric acid having a liquid temperature of 10% at a normal temperature for about 10 minutes from the molten aluminum. The plating line was removed, and a stainless steel wire was obtained, and the wire diameter of the stainless steel wire was investigated in the same manner as above. The wire diameter of the stainless steel wire is described in the column of "the wire diameter of the steel wire after the wire drawing" in the first table.

Next, the 100 mm-thick molten aluminum-plated steel wire obtained above was subjected to a tensile test five times, and the elongation at break was measured from the average. This result is shown in the column of "Elongation at break" in the first table.

Moreover, the torsion test of the molten aluminum-plated steel wire obtained above was performed using the torsion test apparatus of the molten aluminum-plated steel wire shown in FIG. Fig. 3 is a schematic explanatory view of a torsion test apparatus for a molten aluminum plated steel wire.

More specifically, the test leads 13 of the torsion test apparatus are clamped by the chucks 14a and 14b, and the distance between the chuck 14a and the chuck 14b is set to 100 mm by the carriage 16 fixed to the test stand 15. The code 17 (mass: 50 g) is assigned to the load, and the test line 13 is not bent. Next, the chuck 14b is rotated in the direction of the arrow B, and the number of revolutions when the test wire 13 is broken is obtained as an integer value, and this is taken as the number of twists. This measurement result is described in the column of "Twisting Times" in the first table.

[assessment]

It is investigated whether or not the molten aluminum-plated steel wire obtained in each of the examples and the comparative examples satisfies the mathematical formula (I), and the mathematical formula (I) is satisfied in the column of "diagnostic mathematical formula" of "torsity" in the first table. In the case of "○", "X" is described in the case where the mathematical expression (I) is not satisfied.

In addition, the case where the actual measured value of the number of twists measured is equal to or greater than the target value described in the first table is evaluated as "○", and the case where the value is not evaluated is evaluated as "x", and in the first table The column of "Measurement" of "Sex" describes the result.

From the results shown in the first table, according to the respective examples, it was found that a molten aluminum plated steel wire to which wire drawing was applied, which is excellent in torsion property at the time of twisting, can be obtained.

 [Industrial Applicability]  

The molten aluminum plated steel wire obtained by the production method of the present invention can be suitably used, for example, in a wire harness of an automobile or the like.

Claims (2)

 A molten aluminum-plated steel wire is a molten aluminum-plated steel wire having a plating layer on a surface of a steel wire having a diameter of 0.1 to 0.4 mm, and the elongation at break is 5 to 30%, from which the molten aluminum-plated steel wire has been The ratio of the average diameter per 100 mm length of the steel wire from which the plating layer is removed to the minimum diameter of the steel wire satisfies the formula (I): [minimum diameter / average diameter] ≧ [1 - elongation at break (%) / 100 )] (I).    A method for manufacturing a molten aluminum-plated steel wire is a method for manufacturing a molten aluminum-plated steel wire having a plating layer on a surface of a steel wire having a diameter of 0.1 to 0.4 mm, from which the plating layer has been removed The ratio of the average diameter per 100 mm length of the steel wire to the minimum diameter of the steel wire satisfies the formula (I): [minimum diameter / average diameter] ≧ [1 (elongation at break (%) / 100)] (I The wire drawing process is applied to the molten aluminum plated steel wire in such a manner that the elongation at the time of fracture of the molten aluminum plated steel wire is 5 to 30%.