JPH03219025A - Production of aluminized steel wire having high strength and high toughness - Google Patents

Abstract

PURPOSE:To produce an aluminized steel wire having high strength and high toughness and excellent in corrosion resistance by subjecting an aluminized and wiredrawn steel wire to blueing treatment under specific conditions. CONSTITUTION:A steel wire aluminized or plated with Al-containing alloy after heat treatment and then wiredrawn is subjected to blueing treatment at >=480 deg.C so that the relationship represented by T(20+logt)>13000 (where T means blueing temp. expressed by absolute temp. and (t) means blueing time expressed by time) is satisfied. By this method, the high tensile aluminized steel wire free from the occurrence of longitudinal cracks at the time of twisting test and excellent in ductility can be obtained.

Description

Detailed Description of the Invention (Industrial Application Field) This invention is applicable to fishing net ropes, reinforcement of power transmission lines (AC3R
The present invention relates to a method for manufacturing high-tensile aluminum plating used in wires for reinforcing submarine optical fiber cables, or alloy-plated steel wire containing aluminum.

(Prior art) For plated steel wires such as wires for fishing net ropes, aluminum-plated or aluminum-containing alloy-plated steel wires with excellent corrosion resistance are used, but with the recent miniaturization of ships and larger fishing nets, Accordingly, the need for higher tensile strength steel wire is increasing.

As a result of the extensive research that has been carried out to meet these demands, the biggest challenge in achieving a high tensile strength ratio for aluminized steel wire is the ductility of the steel wire, especially the method for evaluating ductility. It has become clear that it is important to establish a technology to suppress the occurrence of cracks that occur in the longitudinal direction of steel wires during twisting tests.

In contrast, WIRE JOURNAL INTERN
ATINAL's VOLUlilEI6 1983 No.
4, page 50, it is stated that by controlling the cementite lamella spacing of the pearlite structure constituting the steel wire to an appropriate size, it is possible to suppress longitudinal cracking in a twist test of a galvanized steel wire.

Also, Special Publication No. 60-26805 and Special Publication No. 60-26
Publication No. 806 discloses that after forming processes such as twisting and spring winding, bluing treatment (20
If the steel wire is subjected to treatment at 0 to 400°C for 20 minutes, the toughness of the steel wire decreases, causing cracking in the longitudinal direction during the twisting test. However, straightening under specific conditions after or during wire drawing It is stated that cracking in the longitudinal direction can be suppressed by applying .

(Problem to be solved by the invention) However, according to the research of the present inventors, even with these techniques, ultra-high tensile strength plated steel wire, for example, wire diameter 5
Tensile strength in mm 190kg f 7mm 2 or more, 3
210kg in mm “7mm” or more, 2 in 2mm
50kg f/mm 2 or more, 340kg at 0.5mm
In the twisting test of plated steel wire of f/mm' or more,
It is not possible to suppress the occurrence of longitudinal cracks.

The present invention improves the ductility of high-tensile plated steel wires used for fishing nets, power transmission line reinforcement wires, submarine optical fiber cable reinforcement wires, etc., and suppresses the occurrence of cracks that occur in the longitudinal direction, especially in twisting tests. The purpose of this invention is to provide a method for producing high-strength, high-toughness aluminized steel wire.

(Means for Solving the Problems) As a result of research into techniques for preventing the occurrence of cracks in the longitudinal direction during twisting tests on coated steel wires, the present inventors have found that (1) aluminum plating treatment or aluminum-containing (2) applying a bending process to the drawn steel wire after aluminum plating or aluminum-containing alloy plating; It has been found that subsequent bluing treatment is extremely effective in suppressing the occurrence of cracks.

(Function) The present invention applies to a steel wire that has been subjected to patenting heat treatment to impart good wire drawability, and then subjected to aluminum plating treatment or aluminum-containing alloy plating treatment and then wire drawing. It is something to do.

In the conventional production of plated steel wire, it has been common practice to apply plating after patenting heat treatment and subsequent wire drawing. However, in the plating process for molten aluminum, silicon alloys, etc., the steel wire is exposed to high temperatures, so the strength improved by the wire drawing process decreases significantly when passing through the plating line, resulting in high-tensile steel wire being exposed to high temperatures. This was an extremely irrational process for manufacturing. However, if the plating treatment is performed after the patenting heat treatment as in the present invention, the decrease in strength will be very slight, and high tensile strength steel wire can be manufactured extremely efficiently by drawing the steel wire. It becomes possible.

FIGS. 1(a) and 1(b) show the conventional process (a) and the example of the present invention (
A comparison with bl is shown. Using an example of the present invention, for example, a 260 kgf/mm2 class steel wire with a wire diameter of 1.6 mm was easily manufactured, and the influence of the conditions on the occurrence of vertical cracking during a twisting test of the aluminized steel wire was investigated. .

Figure 2 shows the wire drawn after aluminizing to 199kgf/mm2.
．． 235kg f/mm2 and 285kg f/mm2
A steel wire with a wire diameter of 5 mm and a strength of ff1n2 was subjected to bluing treatment at a temperature ranging from 400°C to 550°C for 1 time from 10 seconds to 10 minutes, and the effects of bluing conditions on twisting properties were investigated. This is the result of an investigation. ○ mark is 1
99kg f/nm 2, △ mark is 235kgf/mm”
, the mark is the result of 285 kg f 7 mm 2 steel wire,
nm indicates that the crack occurrence rate is 10% or less, and no mark indicates that the crack occurrence rate exceeds 10%.

Only when the bluing temperature T and the bluing time t satisfy the following relationship (1) at a temperature of 480°C or higher, the occurrence of cracks in the longitudinal direction in the twisting test becomes noticeable. It can be seen that it is suppressed. Here, T is the temperature expressed in absolute temperature and t is the bluing time expressed in hours.

The inventors further increased the strength of the steel wire to 180 kg and 17 m.
m2 to 320kgf/mm2, steel wire diameter 0.6
The effect of bluing conditions on the occurrence of cracks in the twisting test was investigated by changing the diameter over a wide range from mm to 9 barrels.

As a result, it was found that cracking was significantly suppressed in all steel wires when bluing was carried out at a temperature of 480°C or higher and the bluing temperature and bluing time satisfied the conditions of equation (1) above. I found it. That is, in order to prevent the occurrence of vertical cracks in a twisting test of a high-tensile aluminized steel wire, it is necessary to perform bluing under appropriate conditions after drawing the wire after plating.

Furthermore, the present inventors conducted quantitative studies on bending and bluing conditions for suppressing the occurrence of cracks.

Figure 4 shows a 201kg wire drawn after aluminum plating 17
mm 7.237kg 17mm' and 275kg
A steel wire with a wire diameter of 5 mm and a strength of This study investigated the effects of The bending process was carried out using a jig having five or more straightening rolls 1 as shown in FIG. Note that 2 is a wire rod. The bending angle θ was controlled by changing the advancing direction and the vertical interval of each roll. In Figure 4, ○ mark is 201kg f 7mm 2△ mark is 2
37kg 17mm', mark is 275kg f#+
In the results for the steel wire of m 2 , a mark of 0 indicates that the incidence of cracking is 10% or less, and a mark of no mark indicates that the incidence of cracking is greater than 10%.

It can be seen that the occurrence of cracks is suppressed only when the bending angle is controlled within the range of 10° to 30° and further bluing is performed at 510°C.

The inventors further increased the strength of the steel wire to 180 kg f 7
mm2 to 320kg 17mm2, wire diameter 0.6
The effect of bending conditions on the occurrence of longitudinal cracks in a twisting test was examined by changing the bending conditions over a wide range from 9 mm to 9 mm. Blueing after processing is from 400℃ to 600℃
The plating was carried out under the conditions of immersion in an aluminum bath at 650° C. for 10 seconds. As a result, they found that the bending angle during straightening of steel wires was controlled within the range of 10° to 30°, and that cracking was controlled in all steel wires when bluing was performed at temperatures above 460°C. We confirmed the effectiveness of bending treatment in suppressing vertical cracking in a twist test of aluminized steel wire.

Next, the present inventors investigated the effect of bluing performed after bending on the occurrence of vertical cracking during a twisting test of an aluminized steel wire.

Figure 5 shows wire drawing after aluminization, 199kg f/+
nm 2.235kg 17mm 2 and 285kg
A steel wire with a wire diameter of 5 mm and a strength of 17 mm 2 is
These are the results of examining the effects of bluing conditions on twisting characteristics by performing bluing treatment at temperatures ranging from 400°C to 550°C and times ranging from 10 seconds to 10 minutes. In addition, prior to bluing, straightening was performed at bending angles of 20° and 35°. ○ mark is 199kgf/Inm2, △ mark is 235
kgf/Inff+2, the mark is the result for a steel wire of 285 kgf/mm, a mark of 0 indicates that the incidence of cracking is 10% or less, and no mark indicates that the incidence of cracking is greater than lθ%.

At a temperature of 460°C or higher, the bluing temperature T and the bluing time t satisfy the following relationship (2) formula % (21), and only when the bending angle is 20°, the longitudinal direction in the twisting test It can be seen that the occurrence of cracks that occur in the process is significantly suppressed. Here, T is the temperature expressed in absolute temperature, and t is the bluing time expressed in time.

The inventors further increased the strength of the steel wire to 180 kg and 17 m.
m 2 to 320 kg 17 mm 2, the wire diameter of the steel wire to 0
．． The effect of bluing conditions on the occurrence of cracking in a twisting test was examined by changing the bluing temperature over a wide range from 6+nm to 9mm.

Note that bending at 18° and 22° was performed here before bluing.

As a result, at a temperature of 460°C or higher, the bluing temperature and bluing time were blued to satisfy the conditions of Equation 11, and the bending angle was set in the range of 10°C to 30°C in the previous bending process. It has been found that cracking in conventional steel wires is significantly suppressed when the steel wires are removed.

In other words, in order to prevent the occurrence of vertical cracks in the twisting test of high-tensile aluminized steel wire, it is necessary to perform both bending and bluing under appropriate conditions after the wire is drawn after plating. If one is not carried out or the conditions are inappropriate even if one is carried out, the occurrence of vertical cracking cannot be suppressed.

Special Publication No. 60-26805 and Special Publication No. 60-2680
In Publication No. 6, bluing treatment is performed after bending, but this is a treatment to remove processing distortion and is carried out at a low temperature of 200 to 400°C. This treatment is essentially different from the bluing treatment of the present invention, which is performed at a high temperature of 460° C. or higher and is performed to improve the ductility of the steel wire.

This invention is applied to drawn high carbon steel wire used as aluminized steel wire, and although the composition of the steel wire is not particularly specified, this treatment improves the strength of the aluminized steel wire. Tensile strength 190kg f/l with wire diameter 5mm
l1m" or more, 210kgf/mm2 or more at 3mm, 250kgf/mm' or more at 2mm, 0.5m
The composition of the steel wire is CO, 75%-1.0%, Si, since the effect is large at 340kg f/mm” or more.
Contains 0.6%-2.0%, MnO, 3% 1.5%,
It is desirable to contain one or more of the following reinforcing elements: Cr 1% or less, Mo 0.2% or less, Vo 3% or less, and Ni 1% or less.

This is due to the following reasons. That is, C,
If the addition range of Si, Mn, Cr, Mo, V, and Ni is less than the amount shown above, the strength of the steel wire before wire drawing is low, so in order to increase the strength of the steel wire, the wire drawing processing rate must be adjusted. It is necessary to make it larger. However, as the degree of wire drawing increases, the ductility in the tensile test decreases, and if the addition range of these elements exceeds the upper limit shown above, structures harmful to the ductility of the steel wire, such as pro-eutectoid cementite, This is because the ductility in the tensile test also decreases.

(Example) The effects of the present invention will be explained in more detail with reference to Examples below.

Example I CO, 82%, Si 0.87%, MnO, 6
A steel wire with a wire diameter of 13 mm containing 3% CrO and 18% CrO was subjected to pachinting heat treatment and then immersed in a molten aluminum-silicon alloy (AI 91% Si 9%) for 10 seconds at 650°C to form an aluminum-silicon alloy plating. After that, the wire was drawn to a wire diameter of 5 tnm to produce a steel wire having a strength of 208 kg f/mm 2 , and the steel wire was subjected to a bluing treatment. This steel wire was subjected to a twisting test to investigate the relationship between the occurrence of cracking, bluing temperature, and time. The results are shown in Table 1.

When the bluing temperature is less than 480°C, the relationship between the bluing temperature and the bluing time T (20+ l
Even if the value of ogt) exceeds 13000, the temperature will return to 48
T (20+logt) value is 130 even above 0°C
If it is less than 00, the occurrence of cracks cannot be suppressed. On the other hand, it has been shown that cracking is suppressed when bluing is carried out at a temperature of 480° C. or higher and the bluing temperature and time satisfy T (20+Iogt) > 13000.

Table 1 Influence of bending and bluing (Example 2) CO, 87%, Si 1.27 %,
Mn 0.90%, VO, 05%,
-NiO,14X, AI 0.029%, Nb
A steel wire with a wire diameter of 7 mm containing 10% O.sub.2 was immersed in a molten aluminum bath at 650°C for 10 seconds after patenting heat treatment, and after being aluminized, it was drawn to a wire diameter of 2 mm to 260 kgf/mm. A steel wire was manufactured using the above-mentioned method 2, and the steel wire was subjected to a bluing treatment.

Table 2 shows the relationship between the blue ink conditions and the presence or absence of cracking in the twisting test of this steel wire.

When the bluing temperature is 480℃ or higher, the blue ink temperature and time are “I” (20+ logt) > 1300
It has been shown that the occurrence of cracks is suppressed only when the condition of 0 is satisfied.

Table 2 Incidence of vertical cracking in twisting test of aluminized steel wire with wire diameter 2n+m Example 3 CO, 98%, Si 0.48%, Mn O, 55
A steel wire with a wire diameter of 7 mm containing 0.008% AI was plated with aluminum silicon alloy by immersing it in a 650°C molten aluminum silicon alloy (A191% Si 9%) bath for 10 seconds after patenting heat treatment. The wire was then drawn to a wire diameter of 2 mm to produce a steel wire having a resistance of 255 kgf/mm', and the steel wire was subjected to a bluing treatment.

Table 3 shows the relationship between crack occurrence and bluing conditions in the twisting test of this steel wire.

Also, when the bluing temperature is less than 480℃ and 480℃
Even with the above, the relationship between bluing temperature and time is 13000
It can be seen that if it is less than that, it is not possible to suppress the occurrence of cracks.

Table 3 Twisting of aluminized steel wire with wire diameter 2WII11 3
Example 4 CO, 82%, Si 0.87%, Mn O, 6
After patenting heat treatment, a steel wire with a wire diameter of 13a+m containing 3% CrO and 18% CrO was immersed for 10 seconds in a molten aluminum-silicon alloy (alloy containing 91% AI and 9% Si) at 650°C. After silicon alloy plating, the wire was drawn to a wire diameter of 5 mm and weighed 208 kg.
A steel wire with a strength of 7 mm 2 was produced, and the steel wire was bent and treated with blue ink. This steel wire was subjected to a twisting test to investigate the relationship between the occurrence of cracking, bending process, bluing temperature, and time. The results are shown in Table 4.

The bending angle during straightening is less than 106 or 30°
In the case of T (20 +
logt) exceeds 12,800, and even if the bending angle is in the range of lO° to 30°, if the bluing temperature is less than 460°C, the relationship between bluing temperature and bluing time is Even if the value of T (20+1ogt) exceeds 12,800, or even if the temperature is 460° C. or higher, the occurrence of cracks cannot be suppressed if the value of T (20+Iogt) is less than 12,800. On the other hand, when the bending angle is in the range of lO° to 30°, the temperature is 460°C or higher, and the bluing temperature and time are T (20+logt)>
It has been shown that cracking can be suppressed when blued to satisfy 12800.

Table 4 Aluminum/silicon plating jI2I with wire diameter 5+11111
Influence of bending force and bluing conditions Example 5 CO, 87%, Si 1.27%, Mn
0.90%, VO, 05%, NiO,
A steel wire with a wire diameter of 2.0IIIT11 containing 14%, Δl 0.029%, and Nb 0.010% was subjected to batentine heat treatment and then placed in a 6508C molten aluminum-silicon alloy (alloy containing A191% Si 9%) bath. to 1
The wire was immersed for 0 seconds, plated with aluminum/silicon alloy, and then drawn to a wire diameter of 0.3+ nm to produce a steel wire with a weight of 360 kg/mm', which was then subjected to bending and bluing.

Table 5 shows the occurrence of cracks in the twisting test of this steel wire.
11 (and the relationship between bending and blue ink conditions.

Cracks occur only when the bending angle is suppressed to a range of 10° to 30°, the blue ink temperature is 460°C or higher, and the bluing temperature and time satisfy the following conditions: "F (20-1-1ogt) >12800" It has been shown that the occurrence of

Table 5 Aluminum solicon plating with wire diameter 0.3 (Foundation) 1
Influence of bending force 1 square and bluing strip ('1) on the incidence of longitudinal cracks of 1 in 12 paper tests of 4 m Example 6 CO, 98%, Si 0.48%, MnO
, 55%, wire diameter 7 containing At 0.008%
mm steel wire, 650° after Ti tenting heat treatment
The wire was immersed in a C molten aluminum bath for 10 seconds to be aluminized and then drawn to a wire diameter of 2 mm to produce a steel wire having a strength of 255 kgf/n+m', which was then subjected to bending and bluing.

Table 6 shows the relationship between the occurrence of cracks in the twisting test of this steel wire and the bending and bluing conditions. If the bending angle is not within the range of 10° to 30°, the bluing is 460°C or higher, and even if the product T (20+ logt) of bluing temperature and time is 12800 or higher, the bluing temperature is 460°C. The relationship between bluing temperature and time is 1 even when the temperature is less than 460°C and above 460°C.
It can be seen that if it is less than 2800, the occurrence of cracks cannot be suppressed even if the bending angle is applied within the range of 10° to 30°.

Table 6 Cotton i! The incidence of vertical cracking was lower than that in the twisting test of 2 mm aluminized steel wire, +IIIJ' addition (effects of the invention) As explained in detail above, the steel wire drawn after aluminized was subjected to specific conditions. By applying bluing treatment, or by bending the drawn plated steel wire after aluminizing it and subsequently applying bluing treatment under specific conditions, it has excellent ductility that does not cause longitudinal cracks in twisting tests. It is possible to produce high-tensile aluminized steel wire, and the industrial value is extremely large.

[Brief explanation of drawings]

Figures 1 (a) and (b) are diagrams showing a comparison of changes in the tensile strength of steel wire in the conventional steel wire manufacturing process and the process of the example of the present invention, and Figure 2 shows the twisting of an aluminized steel wire. A diagram showing the influence of blue ink conditions after aluminized wire drawing on the occurrence of vertical cracks in a test. Figure 3 is a diagram showing an example of a jig for bending steel wire. Figure 4 is an aluminized steel wire. Figure 5 shows the effects of bending and bluing conditions after aluminizing and wire drawing on the occurrence of vertical cracks in the twisting test of aluminized steel wire. FIG. 3 is a diagram showing the influence of bending processing and bluing conditions after aluminized wire drawing. ■... Straightening roll, 2... Wire rod

Claims (2)

[Claims] (1) Following heat treatment, aluminization treatment or aluminum-containing alloy plating treatment is performed, and then the drawn steel wire is subjected to bluing treatment at a temperature of 480°C or higher so as to satisfy the relationship T(20+logt)>13000. A method for manufacturing aluminized steel wire that is characterized by its high strength, high toughness, and excellent corrosion resistance. However, T: Brewing temperature expressed in absolute temperature T: Brewing time expressed in time (2) Following heat treatment, aluminization treatment or aluminum-containing alloy plating treatment is performed, and then the drawn steel wire is passed between multiple rolls at a bending angle of 10° to 30°, and then heated to 460°C or more. T(20+logt)>1 at temperature
A method for manufacturing an aluminized steel wire having high strength, high toughness, and excellent corrosion resistance, which is characterized by performing a bluing treatment so as to satisfy the following relationship: 2800. However, T: Brewing temperature expressed in absolute temperature T: Brewing time expressed in time