U.S. patent application number 16/088469 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 | 20190136359 16/088469 |
Document ID | / |
Family ID | 59964825 |
Filed Date | 2019-05-09 |
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United States Patent
Application |
20190136359 |
Kind Code |
A1 |
MIONO; Tadaaki ; et
al. |
May 9, 2019 |
METHOD FOR PRODUCING HOT DIP ALUMINUM-COATED STEEL WIRE
Abstract
Provided is a method for producing a molten aluminum-plated
steel wire in which a steel wire (2) is immersed in a molten
aluminum plating bath (1), the resulting molten aluminum-plated
steel wire (3) is subsequently pulled up from the molten aluminum
plating bath (1) and a stabilizing member (11) is brought into
contact with the bath surface (10) of the molten aluminum plating
bath (1) and the molten aluminum-plated steel wire (3) at the
boundary between the molten aluminum-plated steel wire (3) and the
bath surface (10) of the molten aluminum plating bath (1), a nozzle
(12) for blowing an inert gas is arranged in a position facing the
stabilizing member (11) with the molten aluminum-plated steel wire
(3) therebetween, and an inert gas is blown from the tip (12a) of
the nozzle (12) toward the boundary at a pressure of 0.1-20
kPa.
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: |
59964825 |
Appl. No.: |
16/088469 |
Filed: |
March 30, 2017 |
PCT Filed: |
March 30, 2017 |
PCT NO: |
PCT/JP2017/013474 |
371 Date: |
September 26, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C23C 2/12 20130101; C23C
2/18 20130101; C22C 21/02 20130101; C23C 2/22 20130101; C23C 2/185
20130101; C23C 2/38 20130101 |
International
Class: |
C23C 2/38 20060101
C23C002/38; C23C 2/12 20060101 C23C002/12; C23C 2/18 20060101
C23C002/18 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2016 |
JP |
2016-070331 |
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, which comprises the steps of:
dipping a steel wire in molten aluminum, and then drawing up a
resulting hot-dip aluminum-coated steel wire from the molten
aluminum; contacting a stabilizing member with the surface of the
molten aluminum and the hot-dip aluminum-coated steel wire at the
boundary between the hot-dip aluminum-coated steel wire and the
surface of the molten aluminum; disposing a nozzle for blowing an
inert gas at a place where the nozzle is faced to the stabilizing
member through the hot-dip aluminum-coated steel wire; and blowing
the inert gas from the tip of the nozzle to the above-mentioned
boundary at a pressure of 0.1 to 20 kPa.
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. The method for producing a hot-dip aluminum-coated steel wire
according to claim 1, wherein the temperature of the molten
aluminum is adjusted to a temperature 20.degree. C. or more higher
than the melting point of the molten aluminum.
4. The method for producing a hot-dip aluminum-coated steel wire
according to claim 2, wherein the temperature of the molten
aluminum is adjusted to a temperature 20.degree. C. or more higher
than the melting point of the molten aluminum.
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 relates 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.
[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. In
recent years, it has been desired to develop an electric wire in
which a metal wire having a weight lighter than the copper wire is
used in view of requirement of weight saving.
[0004] As an electric wire having a weight lighter than the copper
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 of Patent Literature 1). 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 in molten aluminum, and then continuously drawing up
the steel wire from the molten aluminum to the air (see, for
example, paragraph [0024] of Patent Literature 1).
[0005] In addition, as a method for producing a hot-dip
aluminum-coated steel wire, there has been proposed 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 dipping a steel wire in
molten aluminum; and then contacting a stabilization member with a
surface of the molten aluminum and the steel wire when the steel
wire is drawn up from the molten aluminum; providing a nozzle
having an inner diameter of 1 mm to 15 mm so that a tip of the
nozzle is positioned at a place apart from the steel wire in a
distance of 1 mm to 50 mm, and blowing an inactive gas having a
temperature of 200 to 800.degree. C. toward the boundary between
the steel wire and the surface of the molten aluminum in a volume
flow rate of 2 to 200 L/min (see, for example, Patent Literature
2). According to the above-mentioned method for producing a hot-dip
aluminum-coated steel wire, there can be exhibited excellent
effects such that a hot-dip aluminum-coated steel wire having a
uniform wire diameter and hardly having an aluminum lump can be
efficiently produced.
[0006] However, when a hot-dip aluminum-coated steel wire is
produced by the above-mentioned method for producing a hot-dip
aluminum-coated steel wire, there is a possibility that a thin part
of a plating layer is generated on the hot-dip aluminum-coated
steel wire. When the hot-dip aluminum-coated steel wire having a
thin part of a plating layer is subjected to a wire-drawing
process, there is a possibility that the steel wire included in the
hot-dip aluminum-coated steel wire is exposed to the outside, and
that the hot-dip aluminum-coated steel wire is broken due to
fluctuation of drawing resistance of the hot-dip aluminum-coated
steel wire in the wire-drawing process.
PRIOR ART LITERATURES
Patent Literatures
[0007] Patent Literature 1: Japanese Patent Unexamined Publication
No. 2014-185355
[0008] Patent Literature 2: Japanese Patent Unexamined Publication
No. 2015-134961
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0009] 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 producing a hot-dip aluminum-coated steel
wire, which can efficiently provide a hot-dip aluminum-coated steel
wire, and which hardly forms a thin part of a plating film and an
aluminum lump on the surface of the plating film.
Means for Solving the Problems
[0010] 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:
dipping a steel wire in molten aluminum; thereafter drawing up a
resulting hot-dip aluminum-coated steel wire from the molten
aluminum; contacting a stabilizing member with the surface of the
molten aluminum and the hot-dip aluminum-coated steel wire at the
boundary between the hot-dip aluminum-coated steel wire and the
surface of the molten aluminum; disposing a nozzle for blowing an
inert gas at a place where the nozzle is faced to the stabilizing
member through the hot-dip aluminum-coated steel wire; and blowing
the inert gas from the tip of the nozzle to the above-mentioned
boundary at a pressure of 0.1 to 20 kPa; (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) the method for producing a
hot-dip aluminum-coated steel wire according to the above item (1)
or (2), wherein the temperature of the molten aluminum is adjusted
to a temperature 20.degree. C. or more higher than the melting
point of the molten aluminum.
Effects of the Invention
[0011] According to the method for producing a hot-dip
aluminum-coated steel wire of the present invention, there can be
exhibited excellent effects such that a hot-dip aluminum-coated
steel wire can be efficiently produced so that a plating film
having a thin portion of the plating film is hardly formed, and an
aluminum lump is hardly deposited on the surface of the plating
film.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] 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.
[0013] FIG. 2 is a schematic cross-sectional view showing one
embodiment of a steel wire-introducing controller shown in FIG.
1.
[0014] FIG. 3 is a schematic cross-sectional view showing one
embodiment of a liquid surface-controlling device used in the steel
wire-introducing controller shown in FIG. 1 and FIG. 2.
[0015] FIG. 4 is a schematic explanatory view showing the boundary
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.
[0016] 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.
MODE FOR CARRYING OUT THE INVENTION
[0017] 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 dipping the steel wire in molten aluminum;
thereafter drawing up a resulting hot-dip aluminum-coated steel
wire from the molten aluminum; contacting a stabilizing member with
the surface of the molten aluminum and the hot-dip aluminum-coated
steel wire at the boundary between the hot-dip aluminum-coated
steel wire and the surface of the molten aluminum; disposing a
nozzle for blowing an inert gas at a place where the nozzle is
faced to the stabilizing member through the hot-dip aluminum-coated
steel wire; and blowing the inert gas from the tip of the nozzle to
the above-mentioned boundary at a pressure of 0.1 to 20 kPa, as
mentioned above.
[0018] According to the method for producing a hot-dip
aluminum-coated steel wire of the present invention, since the
above-mentioned operations are employed in the method, a hot-dip
aluminum-coated steel wire can be efficiently produced so that a
plating film having a thin portion of the plating film is hardly
formed, and an aluminum lump is hardly deposited on the surface of
the plating film.
[0019] Hereinafter, the method of 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.
[0020] 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.
[0021] According to the method of 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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 by washing with water, and washing again 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 so 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.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] The 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. 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.
[0032] Incidentally, an element such as nickel, chrome, zinc,
copper or iron is possibly inevitably incorporated in the molten
aluminum 1.
[0033] The lower limit of the temperature of the molten aluminum 1
is a temperature which is equal to or higher than the melting
temperature of the molten aluminum 1 when the hot-dip
aluminum-coated steel wire 3 is produced, and is usually a
temperature which is equal to or higher than the melting
temperature of the molten aluminum 1 at atmospheric pressure.
[0034] When the temperature of the molten aluminum 1 is adjusted to
a temperature 20.degree. C. or more higher than the melting point
of the molten aluminum 1, the hot-dip aluminum-coated steel wire 3
can be produced so that a plating film having a thin portion of the
plating film is hardly formed, and an aluminum lump is hardly
deposited on the surface of the plating film, even when the
temperature of the inert gas discharged from the tip 12a of the
nozzle 12 is room temperature (for example, room temperature of
0.degree. C. or higher). Accordingly, the lower limit of the
temperature of the molten aluminum 1 is adjusted preferably to a
temperature 20.degree. C. or more higher than the melting point of
the molten aluminum 1, and more preferably to a temperature
25.degree. C. or more higher than the melting point of the molten
aluminum 1, from the viewpoint of production of the hot-dip
aluminum-coated steel wire 3 so that a plating film having a thin
portion of the plating film is hardly formed, and an aluminum lump
is hardly deposited on the surface of the plating film without an
operation for heating the inert gas discharged from the tip 12a of
the nozzle 12.
[0035] The upper limit of the temperature of the molten aluminum 1
is preferably 800.degree. C. or lower, more preferably 780.degree.
C. or lower, and further preferably 750.degree. C. or lower, from
the viewpoint of improvement in thermal efficiency.
[0036] In addition, it is preferred that the temperature of the
molten aluminum 1 is 650 to 750.degree. C. from the viewpoint of
efficient production of the hot-dip aluminum-coated steel wire 3 so
that a plating film having a thin portion of the plating film is
hardly formed, and an aluminum lump is hardly deposited on the
surface of the plating film.
[0037] Incidentally, the temperature of the molten aluminum 1 is a
temperature as determined by dipping a temperature sensor produced
by inserting a thermocouple into a protective pipe for protecting
the thermocouple in the molten aluminum 1 at a depth of about 300
mm from the surface of the molten aluminum 1 near the steel wire 2
which is drawn up from the molten aluminum 1.
[0038] In the present invention, it is preferred that the steel
wire 2 is passed through a steel wire-introducing controller 8 for
aluminum plating having a heating device 6 for heating the steel
wire 2 and a liquid surface-controlling device 7 for preventing the
surface of the steel wire 2 from adhesion of an oxide film, prior
to dipping of the steel wire 2 in the molten aluminum 1, from the
viewpoint of efficient production of the hot-dip aluminum-coated
steel wire 3 so that a plating film having a thin portion of the
plating film is hardly formed, and an aluminum lump is hardly
deposited on the surface of the plating film.
[0039] As the steel wire-introducing controller 8, there can be
cited, for example, a steel wire-introducing controller 8 shown in
FIG. 2 and the like, and the present invention is not limited to
the exemplified one. FIG. 2 is a schematic cross-sectional view
showing one embodiment of the steel wire-introducing controller 8
shown in FIG. 1. The steel wire-introducing controller 8 has the
heating device 6 and the liquid surface-controlling device 7.
[0040] As shown in FIG. 2, the heating device 6 has a heating
device body 6a having a cylindrical shape, made of, for example,
steel such as 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 of 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 of the 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.
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 as determined
in accordance with a method described in the following working
examples.
[0043] The length of the heating device body 6a shown FIG. 2 can be
a length where 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 m to 5 m or so. In
addition, it is preferred that a diameter of the inside 6b of the
heating device body 6a cannot be absolutely determined, 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 is usually about 1.5 times to about
50 times larger than 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.
[0044] 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. 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 or so.
[0045] 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 to 10 mm or so from the viewpoint of efficient discharge of
the heating gas from the gap D. 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.
[0046] 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.
[0047] As the liquid surface-controlling device 7, there can be
cited, for example, a liquid surface-controlling device 7 shown in
FIG. 3 and the like, and the present invention is not limited to
the exemplified one. FIG. 3 is a schematic cross-sectional view
showing one embodiment of the liquid surface-controlling device 7
used in the steel wire-introducing controller 8 shown in FIG. 1 and
FIG. 2.
[0048] 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 in the direction of arrow
C. The total length L of the liquid surface-controlling device 7 is
preferably 30 mm to 500 mm, more preferably 40 mm to 300 mm, and
furthermore preferably 50 mm to 100 mm.
[0049] 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 9 which is to be dipped in the molten aluminum 1 to a
virtual line P shown in FIG. 3 along a longitudinal direction of
the tubular body 9. The length of the dipping region 9b is usually
preferably 2 mm to 20 mm, and more preferably 5 mm to 15 mm.
[0050] 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 usually preferably 5 mm or more,
and more preferably 10 mm or more.
[0051] 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. 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 prevention of the steel wire 2 from adhesion
of an oxide film.
[0052] The shape of the opening part of the through hole 9a of the
tubular body 9 is arbitrary, and can be circular or other shape.
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.
[0053] 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 are 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 with
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.
[0054] The steel wire 2 passed through the steel wire-introducing
controller 8 as occasion demands is dipped in the molten aluminum
1.
[0055] The line speed of the steel wire 2 is 100 m/min or more from
the viewpoint of efficient production of the hot-dip
aluminum-coated steel wire 3, and is preferably 1000 m/min or
lower, and more preferably 800 mm/min or lower, from the viewpoint
of prevention of scatter of an oxide film formed on the surface of
the molten aluminum 1, and efficient production of the hot-dip
aluminum-coated steel wire 3 having little oxide film adhered to
its surface.
[0056] The period of time for dipping the steel wire 2 in the
molten aluminum 1 (plating period of time) is controlled so that
the plating film formed on the surface of the steel wire 1 has a
predetermined thickness. The period of time for dipping the steel
wire 2 in the molten aluminum 1 (plating period of time) cannot be
absolutely determined because the plating period of time differs
depending on a required thickness of the plating film, a
temperature of the molten aluminum 1 and the like. The plating
period of time is usually 0.3 seconds to 1 second or so.
[0057] Next, as shown in FIG. 1, the steel wire 2 dipped in the
molten aluminum 1 is drawn up 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.
[0058] When the steel wire 2 is drawn up from the molten aluminum 1
in the direction of arrow E as illustrated in FIG. 4, the surface
10 of the molten aluminum is lifted upward together with the
hot-dip aluminum-coated steel wire 3 which is drawn up from the
molten aluminum 1, and thereby a meniscus 17 is formed. When the
tip 17a of the meniscus 17 grows upward, the tip 17a of the
meniscus 17 is solidified to form an aluminum lump. Accordingly,
there is a possibility that the aluminum lump is adhered as a
foreign substance to the surface of the plating film 18 of the
hot-dip aluminum-coated steel wire 3.
[0059] In order to prevent the surface of the hot-dip
aluminum-coated steel wire 3 from adhering the foreign substance
such as an aluminum lump by inhibiting the excess growth of the tip
17a of the meniscus 17 upward, a stabilizing member 11 is contacted
with the surface 10 of the molten aluminum 1 and the hot-dip
aluminum-coated steel wire 3 at the boundary between the hot-dip
aluminum-coated steel wire 3 drawn up from the molten aluminum 1
and the surface 10 of the molten aluminum 1, and a nozzle 12 for
blowing an inert gas is disposed at a place where the nozzle 12 is
faced to the stabilizing member 11 through the hot-dip
aluminum-coated steel wire 3.
[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 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 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 is contacted with the hot-dip
aluminum-coated steel wire 3 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 hot-dip aluminum-coated steel wire 3 at the same time. When the
stabilization member 11 is contacted with both of the surface 10 of
the molten aluminum 1 and the hot-dip aluminum-coated steel wire 3
at the same time as mentioned above, pulsation of the surface 10 of
the molten aluminum 1 is suppressed, and thereby pulsation of the
meniscus 17 is suppressed. Accordingly, a plating film 18 can be
uniformly formed on the surface of the steel wire 2. Incidentally,
when the stabilization member 11 is contacted with the hot-dip
aluminum-coated steel wire 3, the stabilization member 11 can be
slightly pressed toward the hot-dip aluminum-coated steel wire 3 as
occasion demands in order to suppress minute vibration of the
hot-dip aluminum-coated steel wire 3.
[0063] A nozzle 12 for blowing an inert gas is disposed at a place
where the nozzle 12 is faced to the stabilizing member 11 through
the hot-dip aluminum-coated steel wire 3. The tip 12a of the nozzle
12 is placed so that the inert gas is blown to the boundary between
the hot-dip aluminum-coated steel wire 3 and the surface 10 of the
molten aluminum 1. The distance (the shortest distance) from the
hot-dip aluminum-coated steel wire 3 to the tip 12a of the nozzle
12 is preferably 1 mm or more from the viewpoint of avoidance of
contact of the tip 12a of the nozzle 12 with the hot-dip
aluminum-coated steel wire 3, 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 12a of the nozzle 12 is
preferably 50 mm or less, more preferably 40 mm or less, still more
preferably 30 mm or less, furthermore preferably 10 mm or less, and
still furthermore preferably 5 mm or less, from the viewpoint of
production of a hot-dip aluminum-coated steel wire 3 so that the
plating film 18 having a thin portion of the plating film 18 is
hardly formed, and an aluminum lump is hardly deposited on the
surface of the plating film 18.
[0064] The inside diameter of the tip 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 the hot-dip aluminum-coated
steel wire 3 by accurately blowing the inert gas from the tip 12a
of the nozzle 12 to the boundary between the hot-dip
aluminum-coated steel wire 3 and the surface 10 of the molten
aluminum 1. The inside diameter of the tip 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 so that the
plating film 18 having a thin portion of the plating film is hardly
formed, and an aluminum lump is hardly deposited on the surface of
the plating film 18.
[0065] 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.
[0066] 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. Incidentally, 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.
[0067] The pressure of the inert gas exhausted from the tip 12a of
the nozzle 12 is controlled to 0.1 to 20 kPa. According to the
present invention, when the steel wire 2 is dipped in the molten
aluminum 1, and thereafter the hot-dip aluminum-coated steel wire 3
is drawn up from the molten aluminum 1, the pressure of the inert
gas blown from the tip 12a of the nozzle 12 to the boundary between
the hot-dip aluminum-coated steel wire 3 and the surface 10 of the
molten aluminum 1 is controlled to 0.1 to 20 kPa at the tip 12a of
the nozzle 12. Accordingly, the hot-dip aluminum-coated steel wire
3 can be produced so that the plating film 18 having a thin portion
of the plating film is hardly formed, and an aluminum lump is
hardly deposited on the surface of the plating film 18.
[0068] The pressure of the inert gas exhausted from the tip 12a of
the nozzle 12 is 0.1 kPa or higher from the viewpoint of production
of the hot-dip aluminum-coated steel wire 3 so that an aluminum
lump is hardly deposited on the surface. The pressure of the inert
gas is 20 kPa or lower, preferably 10 kPa or lower, and furthermore
preferably 3 kPa or lower, from the viewpoint of production of the
hot-dip aluminum-coated steel wire 3 so that the plating film 18
having a thin portion of the plating film is hardly formed, and an
aluminum lump is hardly deposited on the surface of the plating
film 18.
[0069] Incidentally, the pressure of the inert gas discharged from
the tip 12a of the nozzle 12 is a pressure as determined by
inserting a tube made of stainless steel having an inner diameter
of 0.5 mm into the inert gas inside the nozzle 12 at a place apart
from the tip 12a of the nozzle 12 in a distance of 2 mm so that the
tip of the tube is opposed to the tip 12a of the nozzle 12, and
determining the pressure of the inert gas applied to the tip of the
tube by means of a pressure sensor.
[0070] The volume flow rate of the inert gas discharged from the
tip 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 efficient inhibition of
oxidization of the surface of the meniscus 17. 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 production of the hot-dip
aluminum-coated steel wire 3 so that the plating film 18 having a
thin portion of the plating film is hardly formed, and an aluminum
lump is hardly deposited on the surface of the plating film 18.
[0071] The temperature of the inert gas discharged from the tip 12a
of the nozzle 12 is preferably 10.degree. C. or higher, more
preferably 20.degree. C. or higher, and furthermore preferably
30.degree. C. or higher, from the viewpoint of production of a
hot-dip aluminum-coated steel wire 3 so that the plating film 18
having a thin portion of the plating film is hardly formed, and an
aluminum lump is hardly deposited on the surface of the plating
film 18. 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.
[0072] Incidentally, the temperature of the inert gas discharged
from the tip 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
at a place apart from the tip 12a of the nozzle 12 in a distance of
2 mm.
[0073] The line speed of the hot-dip aluminum-coated steel wire 3
drawing up from the surface 10 of the molten aluminum 1 is not
particularly limited. The average thickness of the plating film 18
formed on the surface of the hot-dip aluminum-coated steel wire 3
can be controlled by appropriately controlling the line speed of
the hot-dip aluminum-coated steel wire 3. Accordingly, it is
preferred that the line speed of the hot-dip aluminum-coated steel
wire 3 is appropriately adjusted in accordance with the average
thickness of the plating film 18 formed on the surface of the
hot-dip aluminum-coated steel wire 3.
[0074] 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 18 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.
[0075] 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.
[0076] The average thickness of the plating film 18 formed on the
surface of the hot-dip aluminum-coated steel wire 3 is preferably 5
.mu.m to 10 .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 diameter of the hot-dip
aluminum-coated steel wire 3.
[0077] The minimum thickness of the thin part of the plating film
18 formed on the surface of the hot-dip aluminum-coated steel wire
3 is preferably 1 .mu.m or more, and more preferably 2 .mu.m or
more, 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
diameter of the hot-dip aluminum-coated steel wire 3.
[0078] Before the steel wire 2 is dipped in the molten aluminum 1,
pre-plating of the surface of the steel wire 2 can be carried out
from the viewpoint of efficient formation of the smooth plating
film 18. The metal used in the pre-plating includes, for example,
zinc, nickel, chrome, an alloy thereof and the like, and the
present invention is not limited only to those exemplified ones. In
addition, the plating layer 18 formed on the surface of the steel
wire by pre-plating can be formed only by one layer. Alternatively,
the plating layer 18 can be formed by plural plating layers made of
the same kind or a different kind of a metal.
[0079] 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 outer diameter.
[0080] The hot-dip aluminum-coated steel wire 3 obtained by the
method for producing a hot-dip aluminum-coated steel wire according
to the present invention can be suitably used, for example, in a
wire harness of an automobile, and the like.
Examples
[0081] 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.
[0082] Examples 1 to 66 and comparative examples 1 to 6 In each of
working examples and each of comparative examples, a hot-dip
aluminum-coated steel wire was produced based on the embodiment as
illustrated in FIG. 1.
[0083] As a steel wire, a steel wire having a diameter shown in
each table, and made of steel shown in each table was used. A steel
wire on which surface was not treated by zinc plating (referred to
as "non" in the column "pre Zn" in each table), or a steel wire
having an average thickness of 5 .mu.m or less of a zinc plating
layer (referred to as "existing" in the column "pre Zn" in each
table) was used. In Table 5, the term "37A" listed in the column of
"kind of steel" means a steel wire made of high carbon steel
containing 0.37% by mass of carbon.
[0084] Incidentally, the steel wire on which surface was not
treated by zinc plating 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.
[0085] In addition, before the steel wire was dipped in the molten
aluminum, the steel wire was passed through the steel
wire-introducing controller 8 shown in FIG. 2, and the steel wire
was preheated to about 400.degree. C. by using the heating device
6. As a heating gas, nitrogen gas was used. Incidentally, a steel
wire connected with a thermocouple was prepared, and the
thermocouple was passed through the heating device 6 together with
the steel wire, to determine the preheating temperature.
[0086] In addition, as the liquid surface-controlling device which
was used in the steel wire-introducing controller 8 shown in FIG.
2, the liquid surface-controlling device 7 as shown in FIG. 3, in
which the shape, size and area of the opening part 9d of the
introducing port 9c of the through hole 9a of the tubular body 9
were the same as those of the opening part 9f of the discharge port
9e of the through hole 9a of the tubular body 9, was used. 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 (area of the opening part of the through hole 9a of
the tubular body 9/area of the cross section of the steel wire) was
adjusted to 57. The steel wire was dipped in the molten aluminum
through the liquid surface-controlling device 7 for 0.3 seconds to
1 second.
[0087] As the molten aluminum, molten aluminum (purity of aluminum:
99.7% or more, referred to as "Al" in the column "kind" of "hot-dip
Al" in each table), molten aluminum containing 4% by mass of
silicon (referred to as "4% Si" in the column "kind" of "hot-dip
Al" in each table), molten aluminum containing 8% by mass of
silicon (referred to as "8% Si" in the column "kind" of "hot-dip
Al" in each table), molten aluminum containing 11% by mass of
silicon (referred to as "11% Si" in the column "kind" of "hot-dip
Al" in each table), or molten aluminum containing 13% by mass of
silicon (referred to as "13% Si" in the column "kind" of "hot-dip
Al" in each table) was used. The steel wire was dipped in the
molten aluminum having a temperature 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.
[0088] At that time, a stabilizing member having a width of 40 mm
was contacted with the surface of the molten aluminum and the
hot-dip aluminum-coated steel wire which was drawn up from the
molten aluminum at the boundary between the hot-dip aluminum-coated
steel wire and the surface of the molten aluminum. Incidentally, as
the stabilizing member, a square rod made of stainless steel of
which surface was wound with a heat-resistant cloth was used. The
length for contacting the hot-dip aluminum-coated steel wire with
the heat-resistant cloth was adjusted to 5 mm.
[0089] In addition, a nozzle having an inner diameter shown in each
table was arranged so that the tip of the nozzle was located at a
place apart from the hot-dip aluminum-coated steel wire in a
distance of 2 mm. An inert gas (nitrogen gas) of which temperature
was controlled to a temperature shown in each table was discharged
from the tip of the nozzle at a volume flow rate shown in each
table, and was blown to the boundary between the hot-dip
aluminum-coated steel wire and the surface of the molten aluminum
at a pressure shown in each table.
[0090] 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 and the minimum thickness of the thin
part of the plating film shown in each table.
[0091] Incidentally, a method for determining the average thickness
of the plating film is shown below. In addition, a method for
determining the minimum thickness of the thin part of the plating
film is described in the following paragraph "(2) Measuring of the
minimum thickness of the thin part of the plating film".
[0092] [Method for Determining Average Thickness of Plating
Film]
[0093] The average thickness of the plating film of the hot-dip
aluminum-coated steel wire obtained in each working example and
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 the method for determining the average
thickness of the plating film of the hot-dip aluminum-coated steel
wire obtained in each working example and each comparative
example.
[0094] As a device 19 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 19 for measuring a
diameter had a pair of a pulley 19c and a pulley 19d which were
positioned in a vertical direction against the steel wire, and a
pair of a light emitting unit 19a and a light receiving unit 19b
which were arranged in a horizontal direction at a central position
between the pulley 19c and the pulley 19d. The light emitting unit
19a and the light receiving unit 19b were arranged so that the
light emitting unit 19a and the light receiving unit 19b were
opposed to each other. The light emitting unit 19a and the light
receiving unit 19b adjacent each other were arranged so that an
angle between the light emitting unit 19a and the light receiving
unit 19b was 90.degree. as shown in FIG. 5.
[0095] 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 19c and the pulley 19d, the
outer diameter of the hot-dip aluminum-coated steel wire 3 was
measured at an interval of about 1.4 mm in the longitudinal
direction of the aluminum-plated steel wire 3 by means of the
device 19 for measuring a diameter. Incidentally, the number of
measurement points of the outer diameter was adjusted to about
71000 points.
[0096] 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.
[0097] [Evaluation of Properties of Plating Film]
[0098] As the properties of the hot-dip aluminum-coated steel wire
obtained in each working example or each comparative example,
adhesion of aluminum lump and stability of the plating film at the
thin part of the plating film having the minimum thickness were
examined in accordance with the following methods. Its results are
shown in each table.
[0099] (1) Adhesion of Aluminum Lump
[0100] A hot-dip aluminum-coated steel wire having a length of 300
m was run at a line speed of 100 m/min, and the outer diameter of
the hot-dip aluminum-coated steel wire was measured over the whole
length of the hot-dip aluminum-coated steel wire. At that time,
whether or not a convex portion due to local increase in outer
diameter exists was examined. Whether or not an aluminum lump
exists in the convex portion due to local increase in outer
diameter was observed with naked eyes, and adhesion of the aluminum
lump was evaluated in accordance with the following evaluation
criteria. Incidentally, the outer diameter of the hot-dip
aluminum-coated steel wire was determined by means of an optical
micrometer commercially available from KEYENCE CORPORATION under
the product number of LS-7000.
[0101] [Evaluation Criteria]
.largecircle.: Adhesion of an aluminum lump is not observed. x:
Adhesion of an aluminum lump is observed.
[0102] (2) Measuring of the Minimum Thickness of the Thin Part of
the Plating Film
[0103] In order to measure the minimum thickness at the thin part
of the plating film, the section of the hot-dip aluminum-coated
steel wire was observed. More specifically, a specimen having a
length of 300 mm was obtained by arbitrarily cutting the hot-dip
aluminum-coated steel wire, and six test pieces were obtained from
the specimen by cutting the specimen. Thereafter, the test pieces
were embedded in a resin. The resulting embedded resin product was
cut, and its cross section was polished, to expose the cross
section of the hot-dip aluminum-coated steel wire. This cross
section was observed with an optical microscope (magnification: 500
times), and the minimum thickness at the thin part of the plating
film was measured. The minimum thickness at the thin part of the
plating film was selected from the six test pieces, and the minimum
thickness was regarded as the minimum thickness of thin part of
plating film.
[0104] (3) Stability of Minimum Thickness of Thin Part of the
Plating Film
[0105] The stability of the minimum thickness of the thin part of
the plating film was evaluated based on the minimum thickness of
the thin part of the plating film obtained in the above, and judged
on the basis of the following evaluation criteria:
[0106] (Evaluation Criteria)
.circleincircle.: The minimum thickness of the thin part of the
plating film is 2 .mu.m or more. .largecircle.: The minimum
thickness of the thin part of the plating film is 1 .mu.m or more
and less than 2 .mu.m. x: The minimum thickness of the thin part of
the plating film is less than 1 .mu.m.
[0107] (4) Comprehensive Evaluation
[0108] In accordance with the results for evaluating the adhesion
of aluminum lump and the stability of minimum thickness of thin
part of the plating film, comprehensive evaluation was carried out
on the basis of the following evaluation criteria:
[0109] (Evaluation Criteria)
.circleincircle.: The evaluation of the adhesion of aluminum lump
is .largecircle., and the evaluation of the stability of minimum
thickness of thin part of the plating film is .circleincircle.
(Excellent). .largecircle.: The evaluation of the adhesion of
aluminum lump and the evaluation of the stability of minimum
thickness of thin part of the plating film are .largecircle.,
respectively (Good). x: The evaluation of x is included in any of
the evaluation of the adhesion of aluminum lump and the evaluation
of the stability of minimum thickness of thin part of the plating
film (Failure).
TABLE-US-00001 TABLE 1 Hot-dip Al Nozzle Kind of steel wire Melting
Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of temp.
hot-dip Al Speed diameter Temp. No. Zn (mm) steel Kind (.degree.
C.) (.degree. C.) (m/min) (mm) (.degree. C.) 1 Non 0.20 SUS304 8%
Si 615 700 300 7.6 780 2 Non 0.20 SUS304 8% Si 615 700 300 7.6 740
3 Non 0.20 SUS304 8% Si 615 700 300 4.0 720 4 Non 0.20 SUS304 8% Si
615 700 300 4.0 720 5 Non 0.20 SUS304 8% Si 615 700 300 3.0 720 6
Non 0.20 SUS304 8% Si 615 700 300 3.0 710 7 Non 0.20 SUS304 8% Si
615 700 300 3.0 670 8 Non 0.20 SUS304 8% Si 615 700 300 3.0 590 9
Non 0.20 SUS304 8% Si 615 700 300 2.4 660 10 Non 0.20 SUS304 8% Si
615 700 300 2.4 580 11 Non 0.20 SUS304 8% Si 615 700 300 2.4 580 12
Non 0.20 SUS304 8% Si 615 700 300 1.7 520 13 Non 0.20 SUS304 8% Si
615 700 300 1.7 520 14 Non 0.20 SUS304 8% Si 615 700 300 1.3 450 15
Non 0.20 SUS304 8% Si 615 700 300 1.1 400 16 Non 0.20 SUS304 8% Si
615 720 300 3.0 590 17 Non 0.20 SUS304 8% Si 615 720 300 2.4 660 18
Non 0.20 SUS304 8% Si 615 720 300 2.4 580 19 Non 0.20 SUS304 8% Si
615 680 300 3.0 590 20 Non 0.20 SUS304 8% Si 615 680 300 2.4 660 21
Non 0.20 SUS304 8% Si 615 680 300 2.4 580 Evaluation of Al-plated
Plating film steel wire Inert gas Minimum Stability of Volume
Average thickness of Adhesion of minimum Compre- Ex. flow rate
Pressure thickness thin part aluminum thickness of hensive No.
(L/min) (kPa) (.mu.m) (.mu.m) lump thin part evaluation 1 100 3.8
7.2 2.1 .largecircle. .circleincircle. .circleincircle. 2 50 0.75
7.4 2.9 .largecircle. .circleincircle. .circleincircle. 3 50 8.0
7.6 1.7 .largecircle. .largecircle. .largecircle. 4 10 0.38 7.2 3.2
.largecircle. .circleincircle. .circleincircle. 5 40 20.0 7.7 1.1
.largecircle. .largecircle. .largecircle. 6 30 10.0 7.7 1.6
.largecircle. .largecircle. .largecircle. 7 10 1.8 6.9 2.8
.largecircle. .circleincircle. .circleincircle. 8 2.5 0.12 8.1 4.8
.largecircle. .circleincircle. .circleincircle. 9 10 3.0 6.5 2.3
.largecircle. .circleincircle. .circleincircle. 10 5.0 0.92 7.8 3.3
.largecircle. .circleincircle. .circleincircle. 11 2.5 0.27 8.5 4.1
.largecircle. .circleincircle. .circleincircle. 12 5.0 4.0 7.1 2.0
.largecircle. .circleincircle. .circleincircle. 13 2.5 1.2 6.9 2.4
.largecircle. .circleincircle. .circleincircle. 14 2.5 4.0 7.6 1.9
.largecircle. .largecircle. .largecircle. 15 2.5 5.0 8.0 1.8
.largecircle. .largecircle. .largecircle. 16 2.5 0.12 7.1 4.4
.largecircle. .circleincircle. .circleincircle. 17 10 3.0 6.8 2.2
.largecircle. .circleincircle. .circleincircle. 18 5.0 0.92 6.9 3.1
.largecircle. .circleincircle. .circleincircle. 19 2.5 0.12 7.1 4.8
.largecircle. .circleincircle. .circleincircle. 20 10 3.0 7.2 2.6
.largecircle. .circleincircle. .circleincircle. 21 5.0 0.92 7.5 3.4
.largecircle. .circleincircle. .circleincircle.
TABLE-US-00002 TABLE 2 Hot-dip Al Nozzle Kind of steel wire Melting
Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of temp.
hot-dip Al speed diameter Temp. No. Zn (mm) steel Kind (.degree.
C.) (.degree. C.) (m/min) (mm) (.degree. C.) 22 Non 0.20 SUS304 Al
660 720 300 3.0 670 23 Non 0.20 SUS304 Al 660 700 300 3.0 670 24
Non 0.20 SUS304 Al 660 680 300 3.0 670 25 Non 0.20 SUS304 4% Si 640
720 300 3.0 670 26 Non 0.20 SUS304 4% Si 640 700 300 3.0 670 27 Non
0.20 SUS304 4% Si 640 680 300 3.0 670 28 Non 0.20 SUS304 4% Si 640
660 300 3.0 670 29 Non 0.20 SUS304 8% Si 615 720 300 3.0 670 30 Non
0.20 SUS304 8% Si 615 680 300 3.0 670 31 Non 0.20 SUS304 8% Si 615
660 300 3.0 670 32 Non 0.20 SUS304 8% Si 615 635 300 3.0 670 33 Non
0.20 SUS304 11% Si 590 700 300 3.0 670 34 Non 0.20 SUS304 11% Si
590 680 300 3.0 670 35 Non 0.20 SUS304 11% Si 590 660 300 3.0 670
36 Non 0.20 SUS304 11% Si 590 640 300 3.0 670 37 Non 0.20 SUS304
11% Si 590 620 300 3.0 670 38 Non 0.20 SUS304 11% Si 590 610 300
3.0 670 39 Non 0.20 SUS304 13% Si 585 700 300 3.0 670 40 Non 0.20
SUS304 13% Si 585 680 300 3.0 670 41 Non 0.20 SUS304 13% Si 585 640
300 3.0 670 42 Non 0.20 SUS304 13% Si 585 605 300 3.0 670
Evaluation of Al-plated Plating film steel wire Inert gas Minimum
Stability of Volume Average thickness of Adhesion of minimum
Compre- Ex. flow rate Pressure thickness thin part aluminum
thickness of hensive No. (L/min) (kPa) (.mu.m) (.mu.m) lump thin
part evaluation 22 10 1.8 7.1 2.6 .largecircle. .circleincircle.
.circleincircle. 23 10 1.8 7.1 3.0 .largecircle. .circleincircle.
.circleincircle. 24 10 1.8 7.1 3.3 .largecircle. .circleincircle.
.circleincircle. 25 10 1.8 7.3 2.5 .largecircle. .circleincircle.
.circleincircle. 26 10 1.8 6.9 2.8 .largecircle. .circleincircle.
.circleincircle. 27 10 1.8 7.5 3.0 .largecircle. .circleincircle.
.circleincircle. 28 10 1.8 7.9 3.2 .largecircle. .circleincircle.
.circleincircle. 29 10 1.8 6.7 2.4 .largecircle. .circleincircle.
.circleincircle. 30 10 1.8 7.2 2.8 .largecircle. .circleincircle.
.circleincircle. 31 10 1.8 7.3 3.3 .largecircle. .circleincircle.
.circleincircle. 32 10 1.8 7.3 3.1 .largecircle. .circleincircle.
.circleincircle. 33 10 1.8 7.1 2.5 .largecircle. .circleincircle.
.circleincircle. 34 10 1.8 7.3 2.9 .largecircle. .circleincircle.
.circleincircle. 35 10 1.8 6.6 3.1 .largecircle. .circleincircle.
.circleincircle. 36 10 1.8 7.1 3.1 .largecircle. .circleincircle.
.circleincircle. 37 10 1.8 7.4 3.2 .largecircle. .circleincircle.
.circleincircle. 38 10 1.8 7.3 3.6 .largecircle. .circleincircle.
.circleincircle. 39 10 1.8 7.4 2.5 .largecircle. .circleincircle.
.circleincircle. 40 10 1.8 7.4 2.6 .largecircle. .circleincircle.
.circleincircle. 41 10 1.8 7.3 2.9 .largecircle. .circleincircle.
.circleincircle. 42 10 1.8 7.2 3.2 .largecircle. .circleincircle.
.circleincircle.
TABLE-US-00003 TABLE 3 Hot-dip Al Nozzle Kind of steel wire Melting
Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of temp.
hot-dip Al speed diameter Temp. No. Zn (mm) steel Kind (.degree.
C.) (.degree. C.) (m/min) (mm) (.degree. C.) 43 Non 0.20 SUS304 8%
Si 615 700 300 7.6 18 44 Non 0.20 SUS304 8% Si 615 700 300 7.6 47
45 Non 0.20 SUS304 8% Si 615 700 300 4.0 84 46 Non 0.20 SUS304 8%
Si 615 700 300 3.0 145 47 Non 0.20 SUS304 8% Si 615 700 300 2.4 142
48 Non 0.20 SUS304 8% Si 615 700 300 1.5 142 49 Non 0.20 SUS304 8%
Si 615 680 300 7.6 47 50 Non 0.20 SUS304 8% Si 615 660 300 7.6 47
51 Non 0.20 SUS304 8% Si 615 645 300 7.6 47 Evaluation of Al-plated
Plating film steel wire Inert gas Minimum Stability of Volume
Average thickness of Adhesion of minimum Compre- Ex. flow rate
Pressure thickness thin part aluminum thickness of hensive No.
(L/min) (kPa) (.mu.m) (.mu.m) lump thin part evaluation 43 100 0.61
7.6 2.7 .largecircle. .circleincircle. .circleincircle. 44 50 1.8
8.0 4.7 .largecircle. .circleincircle. .circleincircle. 45 50 3.0
7.4 2.9 .largecircle. .circleincircle. .circleincircle. 46 10 0.55
7.5 4.1 .largecircle. .circleincircle. .circleincircle. 47 10 1.24
6.6 3.6 .largecircle. .circleincircle. .circleincircle. 48 10 8.0
7.3 1.6 .largecircle. .largecircle. .largecircle. 49 50 1.8 7.2 2.8
.largecircle. .circleincircle. .circleincircle. 50 50 1.8 7.3 3.0
.largecircle. .circleincircle. .circleincircle. 51 50 1.8 7.3 3.4
.largecircle. .circleincircle. .circleincircle.
TABLE-US-00004 TABLE 4 Hot-dip Al Nozzle Kind of steel wire Melting
Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of temp.
hot-dip Al speed diameter Temp. No. Zn (mm) steel Kind (.degree.
C.) (.degree. C.) (m/min) (mm) (.degree. C.) 52 Non 0.07 SUS304 8%
Si 615 700 300 3.0 670 53 Non 0.10 SUS304 8% Si 615 700 300 3.0 670
54 Non 0.30 SUS304 8% Si 615 700 300 3.0 670 55 Non 0.60 SUS304 8%
Si 615 700 300 3.0 670 56 Non 1.00 SUS304 8% Si 615 700 300 3.0 670
57 Non 0.10 SUS304 8% Si 615 700 600 3.0 670 58 Non 0.20 SUS304 8%
Si 615 700 400 3.0 670 59 Non 0.20 SUS304 8% Si 615 700 200 3.0 670
60 Non 0.20 SUS430 8% Si 615 700 300 3.0 670 Evaluation of
Al-plated Plating film steel wire Inert gas Minimum Stability of
Volume Average thickness of Adhesion of minimum Compre- Ex. flow
rate Pressure thickness thin part aluminum thickness of hensive No.
(L/min) (kPa) (.mu.m) (.mu.m) lump thin part evaluation 52 10 1.8
5.4 2.1 .largecircle. .circleincircle. .circleincircle. 53 10 1.8
5.7 2.2 .largecircle. .circleincircle. .circleincircle. 54 10 1.8
7.8 2.4 .largecircle. .circleincircle. .circleincircle. 55 30 10.0
9.8 2.0 .largecircle. .circleincircle. .circleincircle. 56 30 10.0
10.4 2.1 .largecircle. .circleincircle. .circleincircle. 57 10 1.8
6.9 2.6 .largecircle. .circleincircle. .circleincircle. 58 10 1.8
7.4 2.8 .largecircle. .circleincircle. .circleincircle. 59 10 1.8
6.4 2.5 .largecircle. .circleincircle. .circleincircle. 60 10 1.8
7.0 2.2 .largecircle. .circleincircle. .circleincircle.
TABLE-US-00005 TABLE 5 Hot-dip Al Nozzle Kind of steel wire Melting
Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of temp,
hot-dip Al speed diameter Temp. No. Zn (mm) steel Kind (.degree.
C.) (.degree. C.) (m/min) (mm) (.degree. C.) 61 Existing 0.20 37A
8% Si 615 700 300 3.0 670 62 Existing 0.20 37A 8% Si 615 700 300
2.4 580 63 Existing 0.20 37A 8% Si 615 700 300 1.7 520 64 Existing
0.20 37A 8% Si 615 700 300 1.3 450 65 Existing 0.20 37A 8% Si 615
700 300 1.1 400 66 Non 0.20 37A 8% Si 615 700 300 3.0 670
Evaluation of Al-plated Plating film steel wire Inert gas Minimum
Stability of Volume Average thickness of Adhesion of minimum
Compre- Ex. flow rate Pressure thickness thin part aluminum
thickness of hensive No. (L/min) (kPa) (.mu.m) (.mu.m) lump thin
part evaluation 61 10 1.8 7.1 2.4 .largecircle. .circleincircle.
.circleincircle. 62 5.0 0.92 7.4 3.8 .largecircle. .circleincircle.
.circleincircle. 63 2.5 1.2 7.6 2.6 .largecircle. .circleincircle.
.circleincircle. 64 2.5 4.0 6.8 2.1 .largecircle. .circleincircle.
.circleincircle. 65 2.5 5.0 7.0 1.7 .largecircle. .largecircle.
.largecircle. 66 10 1.9 6.9 2.5 .largecircle. .circleincircle.
.circleincircle.
TABLE-US-00006 TABLE 6 Hot-dip Al Nozzle Comp. Kind of steel wire
Melting Temp. of Line Inner Inert gas Ex. Pre Diameter Kind of
temp. hot-dip Al speed diameter Temp. No. Zn (mm) steel Kind
(.degree. C.) (.degree. C.) (m/min) (mm) (.degree. C.) 1 Non 0.20
SUS304 8% Si 615 700 300 7.6 640 2 Non 0.20 SUS304 8% Si 615 700
300 2.4 700 3 Non 0.20 SUS304 8% Si 615 700 300 1.7 660 4 Non 0.20
SUS304 8% Si 615 630 300 7.6 47 5 Non 0.20 SUS304 8% Si 615 700 300
16.0 122 6 Non 0.20 SUS304 8% Si 615 700 300 2.4 700 Evaluation of
Al-plated Plating film steel wire Inert gas Minimum Stability of
Comp. Volume Average thickness of Adhesion of minimum Compre- Ex.
flow rate Pressure thickness thin part aluminum thickness of
hensive No. (L/min) (kPa) (.mu.m) (.mu.m) lump thin part evaluation
1 10 0.05 9.5 5.1 X .circleincircle. X 2 30 26.0 6.9 0.7
.largecircle. X X 3 30 82.0 7.1 0.4 .largecircle. X X 4 50 1.8 6.9
3.0 X .circleincircle. X 5 20 0.006 7.6 3.9 X .circleincircle. X 6
30 26.0 8.2 0.8 .largecircle. X X
[0110] According to each working example, it can be seen that a
hot-dip aluminum-coated steel wire can be efficiently produced so
that a plating film having a thin portion of the plating film is
hardly formed, and an aluminum lump is hardly deposited on the
surface of the plating film, as shown in Tables 1 to 5.
INDUSTRIAL APPLICABILITY
[0111] 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
[0112] 1: molten aluminum [0113] 2: steel wire [0114] 3: hot-dip
aluminum-coated steel wire [0115] 4: delivery device [0116] 5:
plating bath [0117] 6: heating device [0118] 6a: heating device
body [0119] 6b: inside of heating device body [0120] 6c: heating
gas inlet of heating device body [0121] 6d: lower end of heating
device body [0122] 6e: branch pipe of heating device body [0123] 7:
liquid surface-controlling device [0124] 7a: upper end of liquid
surface-controlling device [0125] 8: steel wire-introducing
controller [0126] 9: tubular body [0127] 9a: through hole of
tubular body [0128] 9b: dipping region of tubular body [0129] 9c:
introducing port of tubular body [0130] 9d: opening part of
introducing port of tubular body [0131] 9e: discharge port of
tubular body [0132] 9f: opening part of discharge port of tubular
body [0133] 10: surface of molten aluminum [0134] 11: stabilizing
member [0135] 11a: heat-resistant cloth of stabilizing member
[0136] 12: nozzle [0137] 12a: tip of nozzle [0138] 13: inert
gas-providing apparatus [0139] 14: pipe [0140] 15: cooling device
[0141] 16: winding device [0142] 17: meniscus [0143] 17a: tip of
meniscus [0144] 18: plating film [0145] 19: device for measuring a
diameter of a steel wire by passing through a steel wire [0146]
19a: light-emitting unit of a device for measuring diameter of a
steel wire by passing through a steel wire [0147] 19b: light
receiving unit of a device for measuring a diameter of a steel wire
by passing through a steel wire [0148] 19c: pulley of a device for
measuring a diameter of a steel wire by passing through a steel
wire [0149] 19d: pulley of a device for measuring a diameter of a
steel wire by passing through a steel wire
* * * * *