U.S. patent application number 16/083620 was filed with the patent office on 2019-05-09 for method for producing hot-dip aluminum-coated steel wire.
This patent application is currently assigned to NISSHIN STEEL CO., LTD.. The applicant listed for this patent is NISSHIN STEEL CO., LTD.. Invention is credited to Yasunori HATTORI, Shinichi KAMOSHIDA, Tadaaki MIONO.
Application Number | 20190136358 16/083620 |
Document ID | / |
Family ID | 59790490 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190136358 |
Kind Code |
A1 |
MIONO; Tadaaki ; et
al. |
May 9, 2019 |
METHOD FOR PRODUCING HOT-DIP ALUMINUM-COATED STEEL WIRE
Abstract
A production method for molten-aluminum-plated copper wire, the
production method being characterized by use of a heating device
(6) that is for heating a copper wire (2) before the copper wire
(2) is immersed in a molten aluminum plating bath (1) and of a bath
surface control device (7) that comprises a tube-shaped body (9),
which has a through hole (9a) for passing the copper wire (2)
through the inside thereof, and includes an immersion region (9b)
that is for immersion in the molten aluminum plating bath (1) from
an end part of one end of the tube-shaped body (9) along the long
direction of the tube-shaped body (9). The production method is
also characterized in that the copper wire (2) is passed, in order,
through the heating device (6) and the bath surface control device
(7) and immersed in the molten aluminum plating bath (1) while the
immersion region (9b) of the bath surface control device (7) is
immersed in the molten aluminum plating bath (1).
Inventors: |
MIONO; Tadaaki; (Tokyo,
JP) ; KAMOSHIDA; Shinichi; (Tokyo, JP) ;
HATTORI; Yasunori; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NISSHIN STEEL CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
NISSHIN STEEL CO., LTD.
Tokyo
JP
|
Family ID: |
59790490 |
Appl. No.: |
16/083620 |
Filed: |
March 7, 2017 |
PCT Filed: |
March 7, 2017 |
PCT NO: |
PCT/JP2017/009037 |
371 Date: |
January 18, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 2/00 20130101; C23C
2/38 20130101; C23C 2/12 20130101; C23C 2/003 20130101 |
International
Class: |
C23C 2/38 20060101
C23C002/38; C23C 2/12 20060101 C23C002/12; C23C 2/00 20060101
C23C002/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 11, 2016 |
JP |
2016-047841 |
Claims
1. A method for producing a hot-dip aluminum-coated steel wire by
dipping a steel wire in molten aluminum, and then continuously
drawing up the steel wire from the molten aluminum, to produce a
hot-dip aluminum-coated steel wire, comprising the steps of: using
a heating device for heating a steel wire prior to dipping of the
steel wire in molten aluminum, and a liquid surface-controlling
device comprising a tubular body having a through hole for
introducing the steel wire into the tubular body, wherein the
tubular body has a dipping region for dipping the tubular body in
the molten aluminum from one end part of the tubular body along a
longitudinal direction of the tubular body; introducing the steel
wire into the heating device and the liquid surface-controlling
device sequentially under a condition that the dipping region of
the liquid surface-controlling device is dipped in the molten
aluminum; and dipping the steel wire in the molten aluminum.
2. The method for producing a hot-dip aluminum-coated steel wire
according to claim 1, wherein the steel wire is a steel wire made
of stainless steel or carbon steel.
3. A controller for introducing a steel wire to hot-dip aluminum,
used in producing a hot-dip aluminum-coated steel wire by dipping a
steel wire in molten aluminum, and then continuously drawing up the
steel wire from the molten aluminum, comprising: a heating device
for heating the steel wire prior to dipping of the steel wire in
molten aluminum, and a liquid surface-controlling device comprising
a tubular body having a through hole for introducing the steel wire
into the tubular body, wherein the tubular body has a dipping
region for dipping the tubular body in the molten aluminum from one
end part of the tubular body along a longitudinal direction of the
tubular body.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for producing a
hot-dip aluminum-coated steel wire. More particularly, the present
invention relate to a method for producing a hot-dip
aluminum-coated steel wire which can be suitably used in, for
example, a wire harness of an automobile, and the like, and a
controller for introducing a steel wire to hot-dip aluminum, which
can be suitably used in the method for producing a hot-dip
aluminum-coated steel wire.
[0002] In the present description, the hot-dip aluminum-coated
steel wire means a steel wire which has been plated with aluminum
by dipping a steel wire in molten aluminum, and then continuously
drawing up the steel wire from the molten aluminum. In addition,
the molten aluminum means a plating liquid of molten aluminum.
BACKGROUND ART
[0003] A copper wire has been hitherto used as an electric wire
which is used in a wire harness of an automobile, and the like. As
an electric wire having a light weight without impairing electric
conductivity in place of the copper wire, it has been desired in
recent years to develop a composite electric wire made of a strand
of an aluminum wire having a weight lighter than the copper wire
and a metal wire having strength higher than the aluminum wire. As
a metal wire having strength higher than the aluminum wire, a
hot-dip Al-coated steel wire obtained by plating a steel wire with
hot-dip aluminum has been proposed (for example, see claim 1 and
paragraph [0004] of Patent Literature 1).
[0004] The above-mentioned hot-dip Al-coated steel wire has been
produced by dipping a steel wire or a steel wire having a zinc
plated layer or a nickel plated layer on its surface as a starting
wire in molten aluminum, and then continuously drawing up the steel
wire from the molten aluminum to the air (see, for example,
paragraph of Patent Literature 1).
PRIOR ART LITERATURES
Patent Literatures
[0005] Patent Literature 1: Japanese Patent Unexamined Publication
No. 2014-185355
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0006] In recent years, it has been desired that a steel wire is
dipped in molten aluminum at a high speed of 200 m/min or more in
order to efficiently produce a hot-dip aluminum-coated steel wire.
However, according to the above-mentioned process, when the
starting wire is a steel wire or a steel wire having a nickel
plated layer on its surface, there is a possibility that an
obtained hot-dip aluminum-coated steel wire has an area where a
plating film is not formed on its surface after dipping the steel
wire in molten aluminum, and then continuously drawing up the steel
wire from the molten aluminum to the air.
[0007] The present invention has been made in view of the
above-mentioned prior art. An object of the present invention is to
provide a method for efficiently producing a hot-dip
aluminum-coated steel wire having a plating film over the whole
surface even when a steel wire is dipped in molten aluminum at a
high speed of 200 m/min or more, and a controller for introducing a
steel wire to hot-dip aluminum, which can be suitably used in the
method for producing a hot-dip aluminum-coated steel wire.
Means for Solving the Problems
[0008] The present invention relates to:
(1) a method for producing a hot-dip aluminum-coated steel wire by
dipping a steel wire in molten aluminum, and then continuously
drawing up the steel wire from the molten aluminum, to produce a
hot-dip aluminum-coated steel wire, which includes the steps
of:
[0009] using a heating device for heating a steel wire prior to
dipping of the steel wire in molten aluminum, and a liquid
surface-controlling device including a tubular body having a
through hole for introducing the steel wire into the tubular body,
wherein the tubular body has a dipping region for dipping the
tubular body in the molten aluminum from one end part of the
tubular body along a longitudinal direction of the tubular
body;
[0010] introducing the steel wire into the heating device and the
liquid surface-controlling device sequentially under a condition
that the dipping region of the liquid surface-controlling device is
dipped in the molten aluminum; and [0011] dipping the steel wire in
the molten aluminum; (2) the method for producing a hot-dip
aluminum-coated steel wire according to the above item (1), wherein
the steel wire is a steel wire made of stainless steel or carbon
steel; and (3) a controller for introducing a steel wire to hot-dip
aluminum, used in producing a hot-dip aluminum-coated steel wire by
dipping a steel wire in molten aluminum, and then continuously
drawing up the steel wire from the molten aluminum, which includes
a heating device for heating a steel wire prior to dipping of the
steel wire in molten aluminum, and a liquid surface-controlling
device including a tubular body having a through hole for
introducing a steel wire into the tubular body, wherein the tubular
body has a dipping region for dipping the tubular body in the
molten aluminum from one end part of the tubular body along a
longitudinal direction of the tubular body.
Effects of the Invention
[0012] According to the method for producing a hot-dip
aluminum-coated steel wire and the liquid surface-controlling
device of the present invention, there can be exhibited excellent
effects such that a hot-dip aluminum-coated steel wire having a
plating film over the whole surface can be efficiently produced
even when a steel wire is dipped in molten aluminum at a high speed
of 200 m/min or more.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view showing one embodiment of a
method for producing a hot-dip aluminum-coated steel wire according
to the present invention.
[0014] FIG. 2 is a schematic cross-sectional view showing one
embodiment of a heating device used in a controller for introducing
a steel wire to hot-dip aluminum according to the present
invention.
[0015] FIG. 3 is a schematic cross-sectional view showing one
embodiment of a liquid surface-controlling device used in a
controller for introducing a steel wire to hot-dip aluminum
according to the present invention.
[0016] FIG. 4 is a schematic explanatory view showing a boundary
portion between a steel wire and a surface of molten aluminum when
the steel wire is drawn up from the molten aluminum in the method
for producing a hot-dip aluminum-coated steel wire according to the
present invention.
[0017] FIG. 5 is a schematic explanatory view showing one
embodiment of a method for determining an average thickness of a
plating film of a hot-dip aluminum-coated steel wire obtained in
each of working examples and comparative examples.
[0018] FIG. 6 is a photograph substituted for a drawing, showing
appearance of a hot-dip aluminum-coated steel wire obtained in
Example 2, Example 7 and Comparative Examples 1 and 2.
MODE FOR CARRYING OUT THE INVENTION
[0019] The method for producing a hot-dip aluminum-coated steel
wire according to the present invention includes a process for
dipping a steel wire in molten aluminum, and then continuously
drawing up the steel wire from the molten aluminum, to produce a
hot-dip aluminum-coated steel wire. The method includes one of
characteristics in using a heating device for heating a steel wire
prior to dipping of the steel wire in molten aluminum, and a liquid
surface-controlling device including a tubular body having a
through hole for introducing the steel wire into the tubular body,
wherein the tubular body has a dipping region for dipping the
tubular body in the molten aluminum from one end part of the
tubular body along a longitudinal direction of the tubular body;
introducing the steel wire into the heating device and the liquid
surface-controlling device sequentially under a condition that the
dipping region of the liquid surface-controlling device is dipped
in the molten aluminum; and dipping the steel wire in the molten
aluminum, as mentioned above.
[0020] According to the method for producing a hot-dip
aluminum-coated steel wire of the present invention, a hot-dip
aluminum-coated steel wire having a plating film over the whole
surface can be efficiently produced even when a steel wire is
dipped in molten aluminum at a high speed of 200 m/min or more
since the above-mentioned processes are employed in the method.
[0021] In addition, when a hot-dip aluminum-coated steel wire is
produced by using the liquid surface-controlling device included in
the steel wire-introducing device of the present invention, it is
inhibited that an oxide film generated on the surface of the molten
aluminum is included in the molten aluminum together with the steel
wire at a place where the steel wire is introduced from the air to
the molten aluminum. Thereby reactivity of the steel wire with the
molten aluminum can be improved, and therefore generation of an
area where a plating film is not formed on the surface of the
hot-dip aluminum-coated steel wire can be suppressed.
[0022] In addition, the steel wire can be introduced into the
molten aluminum under the condition that the temperature of the
steel wire is increased since the steel wire is introduced into the
heating device included in the steel wire-introducing device of the
present invention in advance of introduction of the steel wire into
the liquid surface-controlling device. Accordingly, reactivity of
the steel wire with the molten aluminum is improved, and therefore
generation of an area where a plating film is not formed on the
surface of the hot-dip aluminum-coated steel wire can be suppressed
even when a line speed of the steel wire is increased.
[0023] Hereinafter, the method for producing a hot-dip
aluminum-coated steel wire according to the present invention will
be described based on drawings. However, the present invention is
not limited only to those embodiments described in the
drawings.
[0024] FIG. 1 is a schematic explanatory view showing one
embodiment of the method for producing a hot-dip aluminum-coated
steel wire according to the present invention.
[0025] According to the method for producing a hot-dip
aluminum-coated steel wire of the present invention, a steel wire 2
is dipped in molten aluminum 1, and then the steel wire 2 is
continuously drawn up from the molten aluminum 1, to produce a
hot-dip aluminum-coated steel wire 3.
[0026] Examples of steel used in the steel wire 2 include, for
example, stainless steel, carbon steel and the like, and the
present invention is not limited only to those exemplified
ones.
[0027] The stainless steel is an alloy steel containing 10% by mass
or more of chromium (Cr). Examples of the stainless steel include,
for example, austenitic steel materials, ferritic steel materials
and martensitic steel materials defined in JIS G4309, and the like,
and the present invention is not limited only to those exemplified
ones. Specific examples of the stainless steel include stainless
steel in which an austenitic phase is generally considered to be
metastable, such as SUS301 and SUS304; stable austenitic stainless
steel such as SUS305, SUS310 and SUS316; ferritic stainless steel
such as SUS405, SUS410L, SUS429, SUS430, SUS434, SUS436, SUS444 and
SUS447; martensitic stainless steel such as SUS403, SUS410, SUS416,
SUS420, SUS431 and SUS440; chromium-nickel-manganese-based
stainless steel classified into SUS200 series, and the like, and
the present invention is not limited only to those exemplified
ones.
[0028] The carbon steel contains 0.02% by mass or more of carbon
(C). Examples of the carbon steel include, for example, high carbon
steel wire rods defined in JIS G3506, low carbon steel wire rods
defined in JIS G3505, and the like, and the present invention is
not limited only to those exemplified ones. Specific examples of
the carbon steel include high carbon steel, low carbon steel and
the like, and the present invention is not limited only to those
exemplified ones.
[0029] Among the above-mentioned steels, the stainless steel and
the carbon steel are preferred, and the stainless steel is more
preferred, from the viewpoint of increase in tensile strength of
the hot-dip aluminum-coated steel wire 3.
[0030] The diameter of the steel wire 2 is not particularly
limited. It is preferred that the diameter of the steel wire 2 is
appropriately controlled in accordance with uses of the hot-dip
aluminum-coated steel wire 3. For example, when the hot-dip
aluminum-coated steel wire 3 is used in a wire harness of an
automobile and the like, it is preferred that the diameter of the
steel wire 2 is usually 0.05 to 0.5 mm or so.
[0031] The steel wire 2 can be previously degreased before carrying
out hot-dip aluminum plating of the steel wire 2. The degreasing of
the steel wire 2 can be carried out by, for example, a method which
includes dipping the steel wire 2 in an alkaline degreasing liquid,
taking out the steel wire 2 from the alkaline degreasing liquid,
neutralizing the alkaline degreasing liquid deposited on the steel
wire 2, and washing the steel wire 2 with water; a method which
includes carrying out electrolytic degreasing of the steel wire 2
by passing electricity through the steel wire 2 under a condition
such that the steel wire 2 is dipped in an alkaline degreasing
liquid; and the like. Incidentally, the above-mentioned alkaline
degreasing liquid may contain a surfactant from the viewpoint of
improvement in degreasing property.
[0032] A plating film (not shown in the figure) made of aluminum or
an aluminum alloy has been formed on the surface of the hot-dip
aluminum-coated steel wire 3. In the present invention, since the
plating film made of aluminum or an aluminum alloy has been formed
on the surface of the hot-dip aluminum-coated steel wire 3 as
mentioned above, the hot-dip aluminum-coated steel wire 3 is
excellent in adhesiveness to an aluminum wire when a wire harness
is produced by bundling the hot-dip aluminum-coated steel wire 3
with the aluminum wire, and tensile strength and temporal stability
of electric resistance.
[0033] In FIG. 1, the steel wire 2 is provided from a delivery
device 4 of the steel wire 2. Thereafter, the steel wire 2 is
continuously transferred in the direction of arrow A, and dipped in
the molten aluminum 1 charged in a plating bath 5.
[0034] Incidentally, when the steel wire 2 is made of carbon steel,
it is preferred that degreasing of the steel wire 2 is carried out
between the delivery device 4 and the molten aluminum 1, because
there is a possibility that rust is generated on the surface of the
steel wire 2 due to degreasing of the steel wire 2 until hot-dip
aluminum plating of the steel wire 2 is carried out. The degreasing
of the steel wire 2 made of carbon steel can be carried out in the
same manner as the above-mentioned method for degreasing the steel
wire 2.
[0035] The molten aluminum 1 may contain only aluminum.
Alternatively, the molten aluminum 1 may contain an element other
than aluminum as occasion demands within a scope which would not
hinder an object of the present invention. Examples of the element
other than aluminum include, for example, nickel, chromium, zinc,
silicon, copper, iron and the like, and the present invention is
not limited only to those exemplified ones. When the element other
than aluminum is contained in aluminum, mechanical strength of a
plating film can be increased, and moreover, tensile strength of
the hot-dip aluminum-coated steel wire 3 can be increased. Among
the elements other than aluminum, although the kind of the element
depends on the kind of the steel wire 2, silicon is preferred from
the viewpoint of suppression of generation of a brittle
iron-aluminum alloy layer between iron contained in the steel wire
2 and aluminum contained in the plating film, increase in
mechanical strength of the plating film and lowering in melting
point of the molten aluminum 1, thereby increase in efficiency of
plating of the steel wire 2.
[0036] The lower limit of the content of the above-mentioned
element other than aluminum in the plating film is 0% by mass. From
the viewpoint of sufficient exhibition of properties based on the
element other than aluminum, the lower limit thereof is preferably
0.3% by mass or more, more preferably 0.5% by mass or more, and
furthermore preferably 1% by mass or more. From the viewpoint of
suppression of galvanic corrosion caused by contacting with an
aluminum wire, the upper limit thereof is preferably 50% by mass or
less, more preferably 20% by mass or less, and furthermore
preferably 15% by mass or less.
[0037] Incidentally, an element such as nickel, chrome, zinc,
copper or iron is possibly inevitably incorporated in the molten
aluminum 1.
[0038] According to the present invention, the steel wire 2 is
passed through a controller 8 for introducing a steel wire to
hot-dip aluminum, which has a heating device 6 for heating the
steel wire 2 prior to dipping of the steel wire 2 in the molten
aluminum 1, and a liquid surface-controlling device 7. Since the
present invention employs the above processes, a hot-dip
aluminum-coated steel wire 3 having a plating film over the whole
surface can be efficiently produced even when a steel wire is
dipped in molten aluminum at a high speed of 200 m/min or more.
[0039] The heating device 6 used in the controller 8 for
introducing a steel wire to hot-dip aluminum according to the
present invention will be described hereinafter with reference to
FIG. 2. FIG. 2 is a schematic cross-sectional view showing one
embodiment of the heating device 6 used in the controller 8 for
introducing a steel wire to hot-dip aluminum according to the
present invention shown in FIG. 1.
[0040] As shown in FIG. 2, the heating device 6 has a heating
device body 6a having a cylindrical shape, made of, for example,
stainless steel. An inside 6b of the heating device body 6a is
vacant in order to pass through the steel wire 2 in a direction of
arrow B. A branch pipe 6e having a heating gas inlet 6c for
introducing a heating gas is provided at the side surface of the
heating device body 6a.
[0041] The heating gas which is introduced into the heating device
6 includes, for example, air, inert gases such as nitrogen gas,
argon gas and helium gas, and the like, and the present invention
is not limited only to those exemplified ones. Among them, the
inert gases are preferred from the viewpoint of prevention of
oxidization of the molten aluminum 1 existing in the liquid
surface-controlling device 7 by ventilating the heating gas
exhausted from the lower end 6d of the heating device 6 to an
introducing port equipped at the upper end 7a of the liquid
surface-controlling device 7 which is provided below the heating
device 6, to make the inside of the liquid surface-controlling
device 7 an inert gas atmosphere. The temperature of the heating
gas cannot be absolutely determined because the temperature of the
heating gas differs depending on the kind and diameter steel wire 2
being used, conditions such as a line speed of the steel wire 2 and
a flow rate of the heating gas, and the like. Accordingly, it is
preferred that the temperature of the heating gas is controlled so
that the steel wire 2 is appropriately heated under the above
conditions.
[0042] The heating temperature of the steel wire 2 is preferably
60.degree. C. or higher, more preferably 80.degree. C. or higher,
furthermore preferably 150.degree. C. or higher, and still more
preferably 200.degree. C. or higher, from the viewpoint of
efficient production of the hot-dip aluminum-coated steel wire 3
having a plating film over the whole surface even when the speed
for drawing up the hot-dip aluminum-coated steel wire 3 is
controlled to a high speed such as 200 m/min or more. The upper
limit of the heating temperature cannot be absolutely determined
because the upper limit of the heating temperature differs
depending on the kind of the steel wire 2 and the like. It is
preferred that the upper limit of the heating temperature is
usually preferably 1000.degree. C. or lower, more preferably
900.degree. C. or lower, and furthermore preferably 800.degree. C.
or lower, in consideration of energy efficiency. Incidentally, the
above-mentioned heating temperature is a temperature determined in
accordance with a method as described in the following working
examples.
[0043] The upper limit of a line speed of the steel wire 2 is not
particularly limited, and is preferably 1000 m/min or lower, and
more preferably 800 mm/min or lower, from the viewpoint of
efficient production of the hot-dip aluminum-coated steel wire 3
having a plating film over the whole surface.
[0044] The length of the heating device body 6a shown FIG. 2 can be
a length in which the steel wire 2 is heated to a predetermined
temperature, and is not particularly limited. As one example of the
length thereof, for example, the length can be 1 to 5 m or so. In
addition, it is preferred that a diameter of the inside 6b of the
heating device body 6a is appropriately adjusted in accordance with
the diameter and kind of the steel wire 2 being used and the like,
because the diameter of the inside 6b differs depending on the
diameter and kind of the steel wire 2 being used. The diameter of
the inside 6b of the heating device body 6a can be usually
appropriately selected from a range of about 1.5 times to about 50
times of the diameter of the steel wire 2 in accordance with the
diameter of the steel wire 2. As one example of the diameter of the
inside 6b of the heating device body 6a, it is preferred that the
diameter of the inside 6b of the heating device body 6a is, for
example, 0.3 mm to 10 mm or so when the steel wire 2 having a
diameter of 0.2 mm is used.
[0045] The branch pipe 6e having the heating gas inlet 6c is
provided on the side surface of the heating device body 6a. The
steel wire 2 passing through the heating device 6 can be heated by
introducing the heating gas into the heating gas inlet 6c of the
branch pipe 6e. Alternatively, the steel wire 2 can be heated by
providing a heater (not shown in the figure) inside the branch pipe
6e, and heating the heating gas passing through the branch pipe 6e
with the heater.
[0046] In the embodiment shown in FIG. 2, seven branch pipes 6e are
provided. However, the number of the branch pipe 6e is not
particularly limited, and the number of the branch pipe 6e can be
only one, or can be 2 to 10.
[0047] In the embodiment shown in FIG. 2, a gap D is provided
between a lower end 6d of the heating device 6 and an upper end 7a
of the liquid surface-controlling device 7 provided below the
heating device 6. It is preferred that the above-mentioned gap D is
3 mm or more from the viewpoint of efficient discharge of the
heating gas from the gap D, and that the gap D is 10 mm or less
when an inert gas is used as the heating gas, and the inside of the
liquid surface-controlling device 7 is controlled to be an inert
gas atmosphere. Incidentally, there is no necessity that the
above-mentioned gap D is always provided. The heating device 6 can
be separately produced from the liquid surface-controlling device
7, and the heating device 6 and the liquid surface-controlling
device 7 can be united into one body by, for example, screw mating
and the like. When the heating device 6 and the liquid
surface-controlling device 7 are united into one body, an exhaust
port (not shown in the figure) for exhausting the heating gas,
which is passed through the inside of the heating device 6, can be
provided on the side surface of the heating device 6 or the liquid
surface-controlling device 7 as occasion demands.
[0048] Incidentally, a heating device such as an electric heating
device or an induction heating device can be used in place of the
heating device 6 in the present invention.
[0049] Next, the liquid surface-controlling device 7 which is used
in the controller 8 for introducing a steel wire to the hot-dip
aluminum is described on the basis of FIG. 3. FIG. 3 is a schematic
cross-sectional view showing one embodiment of the liquid
surface-controlling device 7 used in the controller for introducing
a steel wire to the hot-dip aluminum 8 according to the present
invention.
[0050] As shown in FIG. 3, the liquid surface-controlling device 7
includes a tubular body 9 having a through hole 9a for introducing
the steel wire 2 into the tubular body 9. The tubular body 9 has a
dipping region 9b for dipping the tubular body 9 in the molten
aluminum 1 from one end part of the tubular body which is to be
dipped in the molten aluminum 1 to a virtual lime P along a
longitudinal direction of the tubular body 9.
[0051] The total length L of the liquid surface-controlling device
7 is preferably 30 mm or more, more preferably 40 mm or more,
furthermore preferably 50 mm or more, from the viewpoint of
prevention of intrusion of the plating liquid of the molten
aluminum 1 into an introducing port 9c for introducing the steel
wire 2 when the dipping region 9b is dipped in the molten aluminum
1, or prevention of intrusion of an oxide film which is generated
on the surface of the molten aluminum 1 into the through hole 9a of
the tubular body 9. The total length L of the liquid
surface-controlling device 7 is preferably 500 mm or less, more
preferably 300 mm or less, and furthermore preferably 100 mm or
less, from the viewpoint of miniaturization of the tubular body 9,
improvement in workability and efficient production of the hot-dip
aluminum-coated steel wire 3 having a plating film over the whole
surface.
[0052] The length of the dipping region 9b is preferably 2 mm or
more, more preferably 5 mm or more, and furthermore preferably 10
mm or more, from the viewpoint of avoidance of affection of swaying
of the surface of the molten aluminum 1, and efficient production
of the hot-dip aluminum-coated steel wire 3 having a plating film
over the whole surface. The length of the dipping region 9b is
preferably 20 mm or less, and more preferably 15 mm or less, from
the viewpoint of miniaturization of the tubular body 9, improvement
in workability, and efficient production of the hot-dip
aluminum-coated steel wire 3 having a plating film over the whole
surface.
[0053] The length of the tubular body 9 along the longitudinal
direction of the tubular body 9 where the tubular body 9 is not
dipped in the molten aluminum 1 is preferably 5 mm or more, and
more preferably 10 mm or more, from the viewpoint of prevention of
intrusion of the plating liquid of the molten aluminum 1 into the
introducing port 9c of the tubular body 9, or prevention of
intrusion of an oxide film which is generated on the surface of the
molten aluminum 1 into the through hole 9a of the tubular body
9.
[0054] A value of a ratio of an area of the opening part of the
through hole 9a of the tubular body 9 to an area of the cross
section of the steel wire 2 used in hot-dip aluminum plating, which
is a so-called cross-section of the steel wire 2 [area of the
opening part of the through hole 9a of the tubular body 9/area of
the cross section of the steel wire 2] is preferably 3 or more from
the viewpoint of smooth introduction of the steel wire 2 into the
through hole 9a of the tubular body 9 and efficient production of
the hot-dip aluminum-coated steel wire 3 having a plating film over
the whole surface. The value of the ratio is preferably 4000 or
less, more preferably 3000 or less, furthermore preferably 2000 or
less, and still more preferably 1000 or less, from the viewpoint of
efficient production of the hot-dip aluminum-coated steel wire 3
having a plating film over the whole surface.
[0055] The shape of the opening part of the through hole 9a of the
tubular body 9 can be circular, oval, or polygon such as square or
rectangle, and the present invention is not limited by the shape
thereof. The gap (clearance) between the opening part of the
through hole 9a of the tubular body 9 and the steel wire 2 is
preferably 10 .mu.m or more, more preferably 20 .mu.m or more,
furthermore preferably 50 .mu.m or more, and still more preferably
100 .mu.m or more, from the viewpoint of avoidance of sliding of an
inner wall of the through hole 9a of the tubular body 9 and the
steel wire 2.
[0056] Incidentally, the opening parts of the through hole 9a
provided in the tubular body 9 are an opening part 9d provided at
the introducing port 9c for introducing the steel wire 2 from one
end of the tubular body 9, and an opening part 9f provided at a
discharge port 9e for discharging the steel wire 2 from another end
of the tubular body 9 as shown in FIG. 3. The area and shape of the
opening part 9d can be the same as those of the opening part 9f
Alternatively, the area and shape of the opening part 9d can be
different from those of the opening part 9f However, it is
preferred that the area and shape of the opening part 9d is the
same as those of the opening part 9f, respectively, as shown in
FIG. 3 from the viewpoint that the steel wire 2 is smoothly passed
through the through hole 9a of the tubular body 9, that sliding of
the inner wall of the through hole 9a of the tubular body 9 and the
steel wire 2 is avoided, and that the hot-dip aluminum-coated steel
wire 3 having a plating film over the whole surface is efficiently
produced.
[0057] The steel wire 2 is introduced to the introducing port 9c of
the tubular body 9 which constructs the liquid surface-controlling
device 7 shown in FIG. 3. The steel wire 2 is taken out from the
discharge port 9e, and dipped in the molten aluminum 1.
[0058] Next, the steel wire 2 dipped in the molten aluminum 1 is
drawn up upward from the surface 10 of the molten aluminum 1, to
form a plating film made of the molten aluminum 1 on the surface of
the steel wire 2, and thereby the hot-dip aluminum-coated steel
wire 3 is obtained.
[0059] When the steel wire 2 is drawn up from the molten aluminum 1
in the direction of arrow E as illustrated in FIG. 4, it is
preferred that a stabilization member 11 is contacted with the
steel wire 2 at a boundary between the steel wire 2 and the surface
10 of the molten aluminum 1.
[0060] Incidentally, FIG. 4 is a schematic explanatory view showing
the boundary between the steel wire 2 and the surface 10 of the
molten aluminum 1 when the steel wire 2 is drawn up from the molten
aluminum 1 in the method for producing a hot-dip aluminum-coated
steel wire according to the present invention.
[0061] The stabilization member 11 includes, for example, a square
rod made of stainless steel, in which a heat-resistant cloth 11a is
wound around the surface of the square rod, and the like. The
heat-resistant cloth 11a wound around the surface of the square rod
includes, for example, woven fabric and non-woven fabric,
containing a heat-resistant fiber such as a ceramic fiber, a carbon
fiber, an aramid fiber or an imide fiber, and the present invention
is not limited only to those exemplified ones. It is preferred that
a virgin surface (new surface) of the heat-resistant cloth 11a of
the stabilization member 11 is contacted with the steel wire 2 from
the viewpoint of suppression of deposition of an aluminum lump on
the surface of the hot-dip aluminum-coated steel wire 3.
[0062] It is preferred that the stabilization member 11 is
contacted with both of the surface 10 of the molten aluminum 1 and
the steel wire 2 at the same time. When the stabilization member 11
is contacted with both of the surface 10 of the molten aluminum 1
and the steel wire 2 at the same time as mentioned above, pulsation
of the surface 10 of the molten aluminum 1 can be suppressed, and
minute vibration of the steel wire 2 can be suppressed by the
stabilization member 11 during drawing up of the steel wire 2 in
contact of the steel wire 2 with the stabilization member 11.
Thereby a plating film 17 of the molten aluminum 1 can be uniformly
formed on the surface of the steel wire 2. Incidentally, when the
stabilization member 11 is contacted with the steel wire 2, it is
preferred that the stabilization member 11 is slightly pressed
toward the steel wire 2 in order to apply tension to the steel wire
2 as occasion demands from the viewpoint of suppression of minute
vibration of the steel wire 2.
[0063] In the embodiments illustrated in FIG. 1, a nozzle 12 for
blowing an inert gas to the boundary between the steel wire 2 and
the surface 10 of the molten aluminum 1 is provided. In addition,
in the embodiment illustrated in FIG. 4, a tip end 12a of a nozzle
12 is provided so that an inert gas is blown from the tip end 12a
to the boundary between the steel wire 2 and the surface 10 of the
molten aluminum 1.
[0064] According to the present invention, the hot-dip
aluminum-coated steel wire 3 having a uniform outer diameter and
little aluminum lump on its surface can be efficiently produced by
appropriately controlling the distance (the shortest distance) from
the steel wire 2 to a tip end 12a of the nozzle 12, the temperature
of the inert gas discharged from the tip end 12a of the nozzle 12,
an inner diameter of the tip end 12a of the nozzle 12, and a volume
flow rate discharged from the nozzle 12.
[0065] The distance (the shortest distance) from the steel wire 2
to the tip end 12a of the nozzle 12 is preferably 1 mm or more from
the viewpoint of avoidance of a contact of the tip end 12a with the
steel wire 2, and efficient production of the hot-dip
aluminum-coated steel wire 3. The distance (the shortest distance)
from the steel wire 2 to the tip end 12a of the nozzle 12 is
preferably 50 mm or less, more preferably 40 mm or less,
furthermore preferably 30 mm or less, and still more preferably 10
mm or less, from the viewpoint of production of a hot-dip
aluminum-coated steel wire 3 having a uniform outer diameter and
little aluminum lump on its surface.
[0066] The inside diameter of the tip end 12a of the nozzle 12 is
preferably 1 mm or more, and more preferably 2 mm or more, from the
viewpoint of efficient production of a hot-dip aluminum-coated
steel wire 3 by accurately blowing an inert gas from the tip end
12a of the nozzle 12 to the boundary between the steel wire 2 and
the surface 10 of the molten aluminum 1. The inside diameter of the
tip end 12a of the nozzle 12 is preferably 15 mm or less, more
preferably 10 mm or less, and furthermore preferably 5 mm or less,
from the viewpoint of production of a hot-dip aluminum-coated steel
wire 3 having a uniform outer diameter and little aluminum lump on
its surface.
[0067] The inert gas can be provided, for example, from an inert
gas providing apparatus 13 shown in FIG. 1 through a pipe 14 to the
nozzle 12. Incidentally, a flow controller such as a valve (not
shown in the figure) can be provided in the inert gas providing
apparatus 13 or the pipe 14 in order to control the flow rate of
the inert gas.
[0068] The inert gas means a gas which is inert to molten aluminum.
Examples of the inert gas include, for example, nitrogen gas, argon
gas, helium gas and the like, and the present invention is not
limited only to those exemplified ones. Among the inert gases,
nitrogen gas is preferable. The inert gas may contain, for example,
oxygen gas, carbon dioxide gas and the like within a scope which
would not hinder an object of the present invention.
[0069] In FIG. 4, the volume flow rate of the inert gas discharged
from the tip end 12a of the nozzle 12 is preferably 2 L (liter)/min
or more, more preferably 5 L/min or more, and furthermore
preferably 10 L/min or more, from the viewpoint of production of a
hot-dip aluminum-coated steel wire 3 having a uniform outer
diameter and little aluminum lump on its surface. The volume flow
rate of the inert gas thereof is preferably 200 L/min or less, more
preferably 150 L/min or less, and furthermore preferably 100 L/min
or less, from the viewpoint of suppression of deposition of an
aluminum lump on the surface of the hot-dip aluminum-coated steel
wire 3 due to scattering of the molten aluminum 1.
[0070] The temperature of the inert gas discharged from the tip end
12a of the nozzle 12 is preferably 200.degree. C. or higher, more
preferably 300.degree. C. or higher, and furthermore preferably
400.degree. C. or higher, from the viewpoint of production of a
hot-dip aluminum-coated steel wire 3 having a uniform outer
diameter and little aluminum lump on its surface. The temperature
of the inert gas thereof is preferably 800.degree. C. or lower,
more preferably 780.degree. C. or lower, and furthermore preferably
750.degree. C. or lower, from the viewpoint of increase in thermal
efficiency. Incidentally, the temperature of the inert gas
discharged from the tip end 12a of the nozzle 12 is a temperature
as determined by inserting a thermocouple for measuring a
temperature, such as a sheath thermocouple having a diameter of 1.6
mm into the inert gas apart from the tip end 12a of the nozzle 12
in a distance of 2 mm.
[0071] The line speed in drawing up the hot-dip aluminum-coated
steel wire 3 from the surface 10 of the molten aluminum 1 is not
particularly limited. It is preferred that the line speed is
appropriately controlled in accordance with the average thickness
of a plating film formed on the surface of the hot-dip
aluminum-coated steel wire 3. The average thickness of the plating
film 17 formed on the surface of the hot-dip aluminum-coated steel
wire 3 can be appropriately controlled by adjusting the line
speed.
[0072] In the present invention, even when the line speed of the
hot-dip aluminum-coated steel wire 3 is controlled to a high speed
such as 200 m/min or more, the hot-dip aluminum-coated steel wire 3
having a uniform outer diameter and a plating film 17 formed over
the whole surface can be produced. Accordingly, the method for
producing a hot-dip aluminum-coated steel wire 3 according to the
present invention is excellent in industrial productivity of the
hot-dip aluminum-coated steel wire 3, because the hot-dip
aluminum-coated steel wire 3 having a plating film 17 formed over
the whole surface can be efficiently produced.
[0073] Incidentally, a cooling device 15 can be provided above the
nozzle 12 as occasion demands as illustrated in FIG. 1 in order to
cool the hot-dip aluminum-coated steel wire 3 in the course of
drawing up of the hot-dip aluminum-coated steel wire 3, and
efficiently solidify the plating film 17 formed on the surface of
the hot-dip aluminum-coated steel wire 3. The hot-dip
aluminum-coated steel wire 3 can be cooled by blowing, for example,
gas, liquid mist or the like to the hot-dip aluminum-coated steel
wire 3 in the cooling device 15.
[0074] The hot-dip aluminum-coated steel wire 3 produced in the
above can be collected by means of, for example, a winding device
16 or the like as shown in FIG. 1.
[0075] The average thickness of the plating film formed on the
surface of the hot-dip aluminum-coated steel wire 3 is preferably 2
.mu.m to 20 .mu.m or so, more preferably 4 .mu.m to 15 .mu.m or so,
from the viewpoint of suppression of exposure of the steel wire 2
included in the hot-dip aluminum-coated steel wire 3 to the air in
carrying out a process such as a wire stranding process or a
crimpling process, and increase in mechanical strength per unit
outer diameter of the hot-dip aluminum-coated steel wire 3.
[0076] The hot-dip aluminum-coated steel wire 3 obtained in the
above can be subjected to a drawing process using dies and the like
as occasion demands so that the hot-dip aluminum-coated steel wire
3 has an appropriate diameter.
[0077] The hot-dip aluminum-coated steel wire 3 obtained in the
present invention can be suitably used, for example, in a wire
harness of an automobile, and the like.
Examples
[0078] Next, the present invention will be more specifically
described based on working examples. However, the present invention
is not limited only to those working examples.
[0079] A hot-dip aluminum-coated steel wire was produced based on
the embodiment as illustrated in FIG. 1.
[0080] As a steel wire, a steel wire having a diameter shown in
each table, and made of steel shown in each table was used. The
term "37A" listed in the column of "kind" of "steel wire" in Table
2 and Table 3 means a steel wire made of high carbon steel
containing 0.37% by mass of carbon.
[0081] Incidentally, the steel wire was subjected to degreasing by
dipping the steel wire in a degreasing liquid containing sodium
orthosilicate and a surfactant, before the steel wire was dipped in
the hot-dip aluminum.
[0082] The steel wire was heated at a heating temperature shown in
each table by introducing the steel wire into a heating device,
before the steel wire was introduced into a liquid
surface-controlling device. As the heating device, a heating device
having a heating device body of which inner diameter is 10 mm, and
eight branch pipes in each of which a Kanthal.RTM. wire (not shown
in the figure) wound in a coil shape was built. An introducing gas
shown in each table was supplied to each branch pipe, to heat the
introducing gas, and the heated introducing gas was introduced to
the inside of the heating device body, to preheat the steel wire.
Incidentally, a steel wire connected with a thermocouple was
prepared, and the thermocouple was passed through the heating
device together with the steel wire, to determine the preheating
temperature.
[0083] As the liquid surface-controlling device, a liquid
surface-controlling device 7 shown in FIG. 3, which was produced by
assembling blocks or square bars made of stainless steel, was used.
The liquid surface-controlling device 7 had a total length L of 100
mm, and the shape, size and area of the opening part 9d of the
introducing port 9c of the through hole 9a were the same as those
of the opening part 9f of the discharge port 9e of the through hole
9a. The shape, size and area of the opening part of the through
hole 9a of the liquid surface-controlling device 7, and the value
of the ratio of the area of the opening part of the through hole 9a
of the tubular body 9 to the area of the cross section of the steel
wire (referred to as "value of area ratio" in each table) were
listed in each table. The dipping region 9b having a length of 10
mm from the lower end of the liquid surface-controlling device 7
was dipped in the molten aluminum, and the steel wire being
introduced into the liquid surface-controlling device 7 was
subsequently dipped in the molten aluminum.
[0084] As the molten aluminum, molten aluminum containing 8% by
mass of silicon (referred to as "8% Si" in the column "kind" of
"hot-dip Al" in each table) was used. The steel wire was dipped in
the molten aluminum at a temperature of the molten aluminum shown
in each table at a line speed (speed of drawing up of steel wire)
shown in each table, and then the steel wire was drawn up from the
molten aluminum.
[0085] A nozzle having an inner diameter of 3 mm at the tip was
provided so that the tip of the nozzle was positioned at a place
apart from the steel wire in a distance of 2 mm. An inert gas
(nitrogen gas) of which temperature was controlled to 600.degree.
C. was discharged from the tip of the nozzle at a volume flow rate
of 10 L/min, and was blown to the boundary between the steel wire
and the surface of the molten aluminum.
[0086] The above operations were carried out, to obtain a hot-dip
aluminum-coated steel wire having a plating film of an average
thickness shown in each table. Incidentally, a method for
determining the average thickness of the plating film is as
follows:
[0087] [Method for Determining Average Thickness of Plating
Film]
[0088] The average thickness of a plating film of a hot-dip
aluminum-coated steel wire obtained in each example or each
comparative example was determined on the basis of an embodiment
shown in FIG. 5. FIG. 5 is a schematic explanatory view showing one
embodiment of a method for determining an average thickness of a
plating film of a hot-dip aluminum-coated steel wire obtained in
each of working examples and comparative examples.
[0089] As a device 18 for measuring a diameter of a steel wire by
passing through the steel wire, a device for measuring a diameter
having two optical micrometers each of which was commercially
available from KEYENCE CORPORATION under the product number of
LS-7000 was used as shown in FIG. 5. The device 18 for measuring a
diameter had a pair of a pulley 18c and a pulley 18d which were
positioned in a vertical direction against the steel wire, and a
pair of a light emitting unit 18a and a light receiving unit 18b
which were arranged in a horizontal direction at a central position
between the pulley 18c and the pulley 18d. The light emitting unit
18a and the light receiving unit 18b were arranged so that the
light emitting unit 18a and the light receiving unit 18b were
opposed to each other. The light emitting unit 18a and the light
receiving unit 18b adjacent each other were arranged so that an
angle between the light emitting unit 18a and the light receiving
unit 18b was 90.degree. as shown in FIG. 5.
[0090] While the hot-dip aluminum-coated steel wire 3 having a
length of 100 m obtained in each working example or each
comparative example was being run at a line speed of 100 m/min in a
direction of arrow F between the pulley 18c and the pulley 18d, the
outer diameter of the hot-dip aluminum-coated steel wire 3 was
measured at an interval of a length of about 1.4 mm in the
longitudinal direction of the aluminum-plated steel wire 3 by means
of the device 18 for measuring a diameter. The number of
measurement points of the outer diameter was adjusted to about
71000 points.
[0091] Next, an average value of the outer diameters of the hot-dip
aluminum-coated steel wire as measured in the above was calculated.
The value of the diameter of the steel wire before forming a
plating film (diameter of steel wire shown in the following each
table) was subtracted from the average value, and an obtained value
was divided by 2, to give an average thickness of a plating film.
The results are shown in each table.
[0092] [Stability of Plating Film]
[0093] As a property of the hot-dip aluminum-coated steel wire
obtained in each working example or each comparative example,
stability of a plating film was examined in accordance with the
following method. The results are shown in each table.
[0094] The surface of the hot-dip aluminum-coated steel wire having
a length of 100 m, obtained in each working example or each
comparative example was observed over the entire length with a
naked eye by using a microscope. When a portion where a plating
film was not formed on the surface of the steel wire was observed,
the length of the portion where a plating film was not formed was
measured by pulling out the steel wire within a range from 250 mm
before the portion where a plating film was not formed to 250 mm
after the portion where a plating film was not formed [hereinafter
referred to as observed length (500 mm)].
[0095] The length of the portion where a plating film was not
formed in the longitudinal direction (hereinafter referred to as
non-plated length) was measured, and non-plated rate was determined
in accordance with the following equation:
[Non-plated rate]={[Non-plated length (mm)]/[Observed length
(mm)]}.times.100. The stability of the plating film was evaluated
in accordance with the following evaluation criteria.
[0096] (Evaluation Criteria of Stability of Plating Film).
5: Non-plated rate is less than 1% (pass). 4: Non-plated rate is 1%
or more and less than 5% (pass). 3: Non-plated rate is 5% or more
and less than 30% (pass). 2: Non-plated rate is 30% or more and
less than 60% (failure). 1: Non-plated rate is 60% or more
(failure).
TABLE-US-00001 TABLE 1 Average Heating device Opening part of
through hole of thickness Steel wire Hot-dip Al Line Heating liquid
surface-controlling device Value of plating Stability Ex. Diameter
Temp. speed temp. Introduc- Size Area of area film of plating No.
(mm) Kind Kind (.degree. C.) (m/min) (.degree. C.) ing gas Shape
(mm) (mm.sup.2) ratio (.mu.m) film Ex. 1 0.20 SUS304 8% Si 700 300
82 Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 5.9 3 Ex. 2 0.20
SUS304 8% Si 700 300 168 Nitrogen Rectangle 0.25 .times. 3.0 0.75
24 6.0 4 Ex. 3 0.20 SUS304 8% Si 700 300 250 Nitrogen Rectangle
0.25 .times. 3.0 0.75 24 5.8 5 Ex. 4 0.20 SUS304 8% Si 700 300 390
Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 5.7 5 Ex. 5 0.20 SUS304
8% Si 700 300 582 Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 6.1 5
Ex. 6 0.20 SUS804 8% Si 700 300 710 Nitrogen Rectangle 0.25 .times.
3.0 0.75 24 5.8 5 Ex. 7 0.20 SUS304 8% Si 700 400 330 Nitrogen
Rectangle 0.25 .times. 3.0 0.75 24 6.4 5 Ex. 8 0.20 SUS304 8% Si
700 300 330 Nitrogen Round .phi.2.0 3.14 100 5.9 5 Ex. 9 0.20
SUS304 8% Si 685 300 390 Nitrogen Rectangle 0.8 .times. 3.0 2.4 76
6.2 5 Ex. 10 0.20 SUS304 8% Si 720 300 390 Nitrogen Rectangle 0.8
.times. 3.0 2.4 76 5.6 5 Ex. 11 0.20 SUS304 8% Si 685 300 390
Nitrogen Rectangle 0.8 .times. 3.0 2.4 76 5.5 5 Ex. 12 0.20 SUS304
8% Si 700 300 390 Nitrogen Rectangle 0.31 .times. 0.31 0.096 3.1
4.4 5 Ex. 13 0.20 SUS304 8% Si 700 300 390 Nitrogen Round .phi.0.35
0.096 3.1 4.5 5 Ex. 14 0.07 SUS304 8% Si 700 600 322 Nitrogen
Rectangle 1.0 .times. 2.0 2.0 520 4.8 5 Ex. 15 0.10 SUS304 8% Si
700 600 333 Nitrogen Rectangle 1.0 .times. 2.0 2.0 255 5.2 5 Comp.
0.20 SUS304 8% Si 700 200 32 Nitrogen Rectangle 0.25 .times. 3.0
0.75 24 5.5 2 Ex. 1 Comp. 0.20 SUS304 8% Si 700 400 32 Nitrogen
Rectangle 0.25 .times. 3.0 0.75 24 5.8 1 Ex. 2 (Note) "Value of
area ratio" means a value of area ratio [area of opening part of
through hole/area of cross section of steel wire].
TABLE-US-00002 TABLE 2 Average Heating device Opening part of
through hole of thickness Steel wire Hot-dip Al Line Heating liquid
surface-controlling device Value of plating Stability Ex. Diameter
Temp. speed temp. Introduc- Size Area of area film of plating No.
(mm) Kind Kind (.degree. C.) (m/min) (.degree. C.) ing gas Shape
(mm) (mm.sup.2) ratio (.mu.m) film Ex. 16 0.15 SUS304 8% Si 700 200
315 Nitrogen Rectangle 1.0 .times. 2.0 2.0 113 5.3 5 Ex. 17 0.30
SUS304 8% Si 700 300 302 Nitrogen Rectangle 2.0 .times. 3.0 6.0 85
9.3 5 Ex. 18 0.60 SUS304 8% Si 700 300 282 Nitrogen Rectangle 2.0
.times. 3.0 6.0 21 12.3 5 Ex. 19 1.00 SUS304 8% Si 700 300 240
Nitrogen Rectangle 2.0 .times. 3.0 6.0 8 14.9 5 Ex. 20 0.20 SUS430
8% Si 700 300 82 Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 5.9 3
Ex. 21 0.20 SUS430 8% Si 700 300 168 Nitrogen Rectangle 0.25
.times. 3.0 0.75 24 6.0 4 Ex. 22 0.20 SUS430 8% Si 700 300 390
Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 5.8 5 Ex. 23 0.20 37A
8% Si 700 300 84 Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 5.9 3
Ex. 24 0.20 37A 8% Si 700 300 172 Nitrogen Rectangle 0.25 .times.
3.0 0.75 24 6.1 4 Ex. 25 0.20 37A 8% Si 700 300 394 Nitrogen
Rectangle 0.25 .times. 3.0 0.75 24 5.7 5 Ex. 26 0.20 37A 8% Si 700
300 715 Nitrogen Rectangle 0.25 .times. 3.0 0.75 24 6.2 5 Ex. 27
0.20 37A 8% Si 700 400 340 Nitrogen Rectangle 0.25 .times. 3.0 0.75
24 5.4 5 Ex. 28 0.20 37A 8% Si 700 300 330 Nitrogen Round .phi.2.0
3.14 100 5.5 5 (Note) "Value of area ratio" means a value of area
ratio [area of opening part of through hole/area of cross section
of steel wire].
TABLE-US-00003 TABLE 3 Average Heating device Opening part of
through hole of thickness Steel wire Hot-dip Al Line Heating liquid
surface-controlling device Value of plating Stability Ex. Diameter
Temp. speed temp. Introduc- Size Area of area film of plating No.
(mm) Kind Kind (.degree. C.) (m/min) (.degree. C.) ing gas Shape
(mm) (mm.sup.2) ratio (.mu.m) film Ex. 29 0.20 SUS304 8% Si 700 300
167 Air Rectangle 0.25 .times. 3.0 0.75 24 5.9 3 Ex. 30 0.20 SUS304
8% Si 700 300 330 Air Rectangle 0.25 .times. 3.0 0.75 24 6.2 4
Comp. 0.20 SUS304 8% Si 700 300 32 Air Rectangle 0.25 .times. 3.0
0.75 24 5.4 2 Ex. 3 Ex. 31 0.20 37A 8% Si 700 300 170 Air Rectangle
0.25 .times. 3.0 0.75 24 6.0 3 Ex. 32 0.20 37A 8% Si 700 300 331
Air Rectangle 0.25 .times. 3.0 0.75 24 5.9 4 Comp. 0.20 37A 8% Si
700 300 34 Air Rectangle 0.25 .times. 3.0 0.75 24 5.8 2 Ex. 4
(Note) "Value of area ratio" means a value of area ratio [area of
opening part of through hole/area of cross section of steel
wire].
[0097] Each outer appearance of the hot-dip aluminum-coated steel
wires obtained in Example 2, Example 7 and Comparative Examples 1-2
is shown in FIG. 6. A white arrow shown in the figure denotes the
area where a plating film was not formed (non-plating area) when
the surface of the hot-dip aluminum-coated steel wire was observed.
From the results shown in FIG. 6, it can be seen that a hot-dip
aluminum-coated steel wire having a plating film over the whole
surface can be efficiently produced according to the
above-mentioned working examples.
[0098] In addition, from the results shown in Table 3, it can be
seen that a hot-dip aluminum-coated steel wire having a plating
film over the whole surface can be efficiently produced even when
air is used in place of nitrogen gas as a heating gas for
preheating a steel wire prior to dipping of the steel wire in
molten aluminum, according to the method for producing a hot-dip
aluminum-coated steel wire of the present invention.
[0099] From the above results, according to a method for producing
a hot-dip aluminum-coated steel wire according to each working
example, it can be seen that excellent effects, such that a hot-dip
aluminum-coated steel wire having a plating film over the whole
surface can be efficiently produced, are exhibited even when a
steel wire is dipped in molten aluminum at a high speed of 200
m/min or more.
INDUSTRIAL APPLICABILITY
[0100] The hot-dip aluminum-coated steel wire obtained by the
method for producing a hot-dip aluminum-coated steel wire according
to the present invention can be suitably used in, for example, a
wire harness of automobiles.
DESCRIPTION OF SYMBOLS
[0101] 1: molten aluminum [0102] 2: steel wire [0103] 3: hot-dip
aluminum-coated steel wire [0104] 4: delivery device [0105] 5:
plating bath [0106] 6: heating device [0107] 6a: heating device
body [0108] 6b: inside of heating device body [0109] 6c: heating
gas inlet of heating device body [0110] 6d: lower end of heating
device body [0111] 6e: branch pipe of heating device body [0112] 7:
liquid surface-controlling device [0113] 7a: upper end of liquid
surface-controlling device [0114] 8: controller for introducing a
steel wire [0115] 9: tubular body [0116] 9a: through hole of
tubular body [0117] 9b: dipping region of tubular body [0118] 9c:
introducing port of tubular body [0119] 9d: opening part of
introducing port of tubular body [0120] 9e: discharge port of
tubular body [0121] 9f opening part of discharge port of tubular
body [0122] 10: surface of molten aluminum [0123] 11: stabilizing
member [0124] 11a: heat-resistant cloth of stabilizing member
[0125] 12: nozzle [0126] 12a: tip end of nozzle [0127] 13: inert
gas providing apparatus [0128] 14: pipe [0129] 15: cooling device
[0130] 16: winding device [0131] 17: plating film [0132] 18: device
for measuring a diameter of a steel wire by passing through a steel
wire [0133] 18a: light-emitting unit of a device for measuring
diameter of a steel wire by passing through a steel wire [0134]
18b: light receiving unit of a device for measuring a diameter of a
steel wire by passing through a steel wire [0135] 18c: pulley of a
device for measuring a diameter of a steel wire by passing through
a steel wire [0136] 18d: pulley of a device for measuring a
diameter of a steel wire by passing through a steel
* * * * *