JPH0366386B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a high tensile strength steel wire with excellent ductility. (Prior Art) In recent years, demands for higher strength of hard steel wires such as steel wires for ropes, steel wires for reinforcing tires, steel wires for reinforcing optical fiber cables, and steel wires for long bridges have been increasing. Although intensive research has been carried out on increasing the strength of hard steel wires, the lack of established technology to prevent the deterioration of ductility that occurs with increased strength is a constraint. It has not yet reached the point where high strength has been achieved. For example, the twisting property, which is an important measure of ductility, is determined by heating the steel wire after drawing at high temperature, as described in the paper on page 50 of Wire Journal vol. 16, No. 4 (1983). This can be improved by bluing treatment, but such high-temperature treatment leads to a decrease in strength, and in the case of thin wires such as tire reinforcing steel wires, deterioration in ductility due to surface oxidation cannot be avoided. However, there are limits to the application of this method. On the other hand, this method does not involve heat treatment,
Attempts have also been made to improve ductility by subjecting the drawn steel wire to skin-pass drawing to release tensile residual stress existing on the surface of the drawn steel wire. However, as described in "Effect of die schedule on mechanical properties and residual stress of steel wire" in the material submitted by the 20th Wire Drawing Technology Subcommittee of the Japan Society for Plasticity Processing, published on November 16, 1984, ductility is hardly improved by this method. Thus, at present, no sufficient method has been found to improve the ductility of steel wire. (Problems to be Solved by the Invention) The object of the present invention is to provide a steel wire with excellent ductility that eliminates these drawbacks. (Means for Solving the Problems) As a result of various research into providing a steel wire with excellent ductility, the present inventors have found that the steel wire has a specific composition and
It has a strength of 130Kgf/mm2 or ^more , and actively applies compressive residual stress to the surface of the steel wire after drawing.
The compressive residual stress is determined according to the steel wire strength σ (0.05σ
+23) to (0.35σ+28) Kgf/mm ² It has been found that a hard steel wire with excellent ductility can be obtained. That is, the gist of the present invention is as follows. (1) C0.4-1.0%, Si 2.0% or less, Mn 0.2-1.0% by weight
Contains 2%, P0.02% or less, S0.02% or less,
N is limited to 0.01% or less, the remainder consists of iron and unavoidable impurities, and has a strength of 130Kgf/mm ² or more, and according to the steel wire strength σ (0.05σ
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of +23) to (0.35σ+28) Kgf/mm ² . (2) C0.4-1.0%, Si2.0% or less, Mn0.2 by weight
Contains ~2%, P0.02% or less, S0.02% or less,
Limited to N0.01% or less, and Cr0.05-3%,
Mo0.01~1%, W0.01~1%, Cu0.05~3%,
Contains one or more of Ni0.1-5% and Co0.1-5%, with the balance consisting of iron and unavoidable impurities, and has a strength of 130Kgf/mm2 or ^more , depending on the steel wire strength σ. (0.05σ+23)～
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of (0.35σ+28) Kgf/mm ² . (3) C0.4-1.0%, Si2.0% or less, Mn0.2 in weight%
Contains ~2%, P0.02% or less, S0.02% or less,
Limit N to 0.01% or less, and Al0.001 to 0.1%,
Ti0.001~0.1%, Nb0.001~0.1%, V0.001~0.1
%, B0.0003~0.05%, Mg0.001~0.1%, the balance consists of iron and unavoidable impurities, and has a strength of 130Kgf/mm2 or ^more , and has a steel wire strength σ (0.05σ
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of +23) to (0.35σ+28) Kgf/mm ² . (4) C0.4-1.0% by weight, Si2.0% or less, Mn0.2
Contains ~2%, P0.02% or less, S0.02% or less,
Limited to N0.01% or less, and Cr0.05-3%,
Mo0.01~1%, W0.01~1%, Cu0.05~3%,
Contains one or more of Ni0.1~5%, Co00.1~5%, and Al0.001~0.1%, Ti0.001~
0.1%, Nb0.001~0.1%, V0.001~0.1%,
Contains one or more of B0.0003~0.05%, Mg0.001~0.1%, the balance is iron and unavoidable impurities, and has a strength of 130Kgf/mm2 or ^more , and depends on the steel wire strength σ. (0.05σ+23)
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of ~(0.35σ+28) Kgf/mm ² . The present invention will be explained in detail below. (Function) First, the reason for limiting the steel wire composition as described above will be described. If C is less than 0.4, the required strength cannot be obtained, so
Moreover, since ductility deteriorates significantly when it exceeds 1.0%, the content is limited to 0.4 to 1.0%. Si is added mainly to take advantage of its solid solution hardening effect, but if the amount added exceeds 2%, the ductility decreases significantly, so the upper limit was set at 2.0%. Mn is added to ensure hardenability and fix S, but if it is less than 0.2%, S will not be fixed sufficiently, and if it is added in excess of 2%, the hardenability will no longer increase. Limited to 2.0%. A small amount of P and S is good for improving ductility. If each exceeds 0.02%, it will have a significant negative effect on ductility, so it was limited to 0.02% or less. If N exceeds 0.01%, it will have a negative effect on ductility, so it was limited to 0.01% or less. The above is the basic composition system of the steel wire that is the object of the present invention.
~5%, W0.01~1%, Cu0.05~3%, Ni0.1~
5%, one or more of Co0.1-5% or (B)Al0.001
~0.1%, Ti0.001~0.1%, Nb0.001~0.1%,
V0.001~0.1%, B0.0003~~0.05%, Mg0.001~
It can contain 0.1% of one or more of (A), (B), or both. First, Cr, Mo, W, Cu, Ni, and Co are added for the purpose of increasing strength and corrosion resistance.
Cr less than 0.05%, Mo less than 0.01%, W less than 0.01%,
If Cu is less than 0.05%, Ni is less than 0.1%, and Co is less than 0.1%, their effects on strengthening and corrosion resistance will not be recognized.
The lower limits were set to 0.05% Cu, 0.1% Ni, and 0.1% Co. On the other hand, more than 3% Cr, more than 1% Mo, more than 1% W, more than 3% Cu,
When Ni exceeds 5% and Co exceeds 5%, the effects of these elements on strengthening and corrosion resistance become saturated, while the effect of reducing ductility becomes significant.
%, W1%, Cu3%, Ni5% and Co5% as upper limits. Note that the total amount of these alloying elements is desirably suppressed to 7% or less from the viewpoint of ductility. Next, Al, Ti, Nb, V, B and Mg are N and S
It is added for the purpose of fixing and improving ductility, but Al less than 0.001%, Ti less than 0.001%,
Nb less than 0.001%, V less than 0.001%, B less than 0.0003%,
If Mg is less than 0.001%, N and S cannot be fixed, so Al0.001%, Nb0.001%, V0.001
%, B0.0003% and Mg0.001% were the lower limits. On the other hand, Al over 0.1%, Ti over 0.1, Nb over 0.1%, V 0.1%
At Al0.1%, B0.05%, and Mg0.1%, the N and S fixing effects of these elements become saturated, while the ductility deterioration effect due to nitrides and sulfides of these elements becomes significant. %, Ti0.1%, Nb0.1%, V0.1
%, B0.05% and Mg0.1% are the upper limits. In addition, it is desirable from the viewpoint of ductility to suppress the total amount of these elements to 0.2% or less. Next, the strength of the steel wire is limited to 130 Kgf/mm ² or more because at a strength lower than this, almost no improvement in ductility is observed even if compressive residual stress exists on the surface of the steel wire. Next, the biggest feature of the present invention is that the steel wire is coated on its surface depending on the steel wire strength σ from (0.05σ+23) to (0.35σ+
28) It has a compressive residual stress in the range of Kgf/ ^mm2 . The reason why the compressive residual stress on the surface of the steel wire was determined in this way will be explained below. The ductility of a steel wire is usually determined by the elongation in a tensile test, the reduction of area, the number of rotations until breakage in a twist test (twist value), the form of breakage at that time, or a bending test. Among these ductility evaluation criteria, the one that deteriorates most significantly as the strength of the steel wire increases is the fracture mode in the torsion test. Figure 1 schematically shows the fracture mode of the steel wire 1 in the twisting test, where a indicates a normal fracture situation, but as the strength increases, as shown in figure b, The frequency of abnormal fractures accompanied by large cracks 2 increases. This is due to the fact that cracks 2 occur in the longitudinal direction on the surface of the steel wire 1 during a twisting test conducted by gripping the steel wire 1 with a gripping jig 3, as schematically shown in Fig. 2. Therefore, the occurrence of abnormal fracture can be considered to mean deterioration of the ductility of the steel wire in the circumferential direction. The fact that the ductility of steel wire in the circumferential direction is most likely to deteriorate as the strength increases is actually during bending of steel wire.
This can also be understood from the fact that vertical cracks may occur in the longitudinal direction even though bending breaks do not occur, and that longitudinal cracks may also occur when twisted wires are processed, even though twist breaks do not occur. . In this way, it can be said that the fracture mode in the torsion test is the most important ductility evaluation criterion for steel wire. The present inventors discovered that having compressive residual stress on the surface of a steel wire is extremely effective in improving the circumferential ductility of the steel wire, and determined the appropriate range of compressive residual stress to be applied. investigated. In other words, the tensile strength was 152Kgf/mm ² and 235Kg, with the goal of suppressing the incidence of abnormal fractures in torsion tests to 10% or less.
Using steel wires of f/mm ² , 316 Kgf/mm ² and 377 Kgf/mm ² , the relationship between the surface compressive residual stress and the incidence of abnormal fracture was investigated. As a result, a steel wire with a tensile strength of 152Kgf/ ^mm2 has a tensile strength of 29
Kgf/mm ² , 36Kgf/mm ² for steel wire of 235Kgf/mm ² ,
316Kgf/mm ² steel wire is 38Kgf/mm ² , 377Kgf/mm ²
It has become clear that a compressive residual stress of 42 Kgf/mm ² or more is necessary for steel wires in order to suppress the incidence of abnormal fracture in torsion tests to 10% or less. When the compressive residual stress obtained here is arranged with respect to the tensile strength σ of the steel wire, the following relationship is experimentally obtained: (0.05σ+23)Kgf/mm ² . If the incidence of abnormal fractures in the twisting test is 10% or less, there is no need to worry about vertical cracks occurring when actually processing the steel wire. For this reason, the lower limit of compressive residual stress to be added to the surface was set to (0.05+23) Kgf/mm ² according to the steel wire strength σ. On the other hand, the larger the compressive residual stress on the surface of the steel wire is, the more desirable it is for improving the ductility in the circumferential direction, but as is well known, the tensile residual stress at the center of the steel wire increases in proportion to the compressive residual stress on the surface. When the tensile residual stress at the center of the steel wire increases, a crack occurs at the center, leading to abnormal fracture during the twisting test. Therefore, the upper limit of the compressive residual stress allowed on the surface of the steel wire is naturally determined by the relationship with the crack at the center of the steel wire. Therefore, the present inventors used the above-mentioned four types of steel wires to investigate the relationship between the occurrence of abnormal fractures in twisting tests due to cracks at the center of the steel wires and compressive residual stress. As a result, tensile strength
For 152Kgf/mm ² steel wire, 80Kgf/mm ² and 235Kgf/
113Kgf/mm ² for mm ² steel wire, 136Kgf/mm ² for 316Kgf/mm ² steel wire, 160Kg for 377Kgf/mm ² steel wire
It has become clear that abnormal fracture occurs when the surface compressive residual stress exceeds f/mm ² . This compressive residual stress is proportional to the steel wire strength σ, which is (0.35σ +
28) Given experimentally as Kgf/mm ² . The upper limit of the compressive residual stress (0.35σ+28) Kgf/mm ² was determined in this way. Note that the compressive residual stress may be applied mechanically by any means, but as a means for applying the compressive residual stress within the range limited in the present invention to the surface of the steel wire after wire drawing, for example, roller rolling or cylinder processing may be used. Yotsuto peening processing can be used. Such compressive residual stress may be applied at any step after wire drawing until the steel wire is used as a product, but if it is applied after bluing or plating, it must be applied at temperatures below 250°C. In order to improve the stress relaxation properties of the steel wire, it is preferable to perform the bluing treatment again at a temperature of . The steel wire of the present invention also has excellent fatigue properties, corrosion fatigue properties, stress corrosion cracking properties, and setting resistance. The steel wire of the present invention is also effective in improving the durability and fatigue properties of products made using the steel wire, such as ropes, steel wire-reinforced tires, and steel wire-reinforced plastics. Next, the effects of the present invention will be explained in more detail with reference to Examples. (Example) Composition, wire diameter, tensile strength, and
The lower limit value (0.05σ + 23) and upper limit value (0.35σ + 28) of the compressive residual stress on the steel wire surface limited in the present invention, the residual stress existing on the surface of the steel wire used in the example,
And these steel wires were subjected to twisting tests, fatigue tests,
As a result of conducting corrosion fatigue tests, delayed fracture tests, and fatigue tests, the results of fatigue tests on products manufactured using these steel wires are also listed in Table 1. In addition, the criteria or means for various tests in the same table are as follows. First, the + symbol for residual stress indicates tensile residual stress, and the - symbol indicates compressive residual stress. Next, the abnormal rupture rate in the twisting test indicates the rate at which the abnormal rupture shown in FIG. 1b occurs in the twisting test. Corrosion fatigue life indicates the number of rotations until the steel wire breaks under a load of 20 kgf/mm ² in a rotating bending fatigue test in 3% saline solution. Cord breakage rate in tires is 100,000 at a load of 500Kg
This shows the breakage rate of cords in tires after driving Km. Settling rate indicates the residual shear strain after applying torsional stress of 60% of the tensile strength to the steel wire and leaving it for 96 hours. Delayed failure time is 80Kgf/mm ² in 0.1N hydrochloric acid solution
It shows the time until rupture when a tensile stress of . The fatigue limit ratio of a plastic plate is the fatigue limit in bending fatigue of a 1 mm thick x 10 mm wide plastic plate reinforced with 100 steel wires per 1 mm ² , with the fatigue limit of a comparative example of a plastic plate reinforced with steel wire as 1. Contrast. The rope fatigue limit ratio is the bending fatigue limit of the JIS No. 1 rope, and the fatigue limit of the rope manufactured with the steel wire of the comparative example is set as 1, and the fatigue limit of the rope manufactured with the steel wire of the invention example is shown in comparison. Pressure corrosion cracking time indicates the time until rupture when a tensile stress of 70 Kgf/mm ² is applied in a 0.5% acetic acid + 5% saline solution. Fatigue limit indicates the fatigue limit stress in a rotating bending fatigue test of steel wire. Next, in Table 1, Test Nos. 1 to 8 are related to Invention 1, Test Nos. 1, 3, and 4 are related to the present invention, and the others are comparative examples. No. 1 and 2 are the results for steel wires having the same composition with a wire diameter of 0.2 mm and a tensile strength of 332 Kgf/mm ² . Of these, No. 1 steel wire has a compressive residual stress of 112 Kgf/mm ² . The abnormal rupture rate of the torsion test is 0. Note that the compressive residual stress is imparted by roller rolling. On the other hand, the abnormal rupture rate of No. 2 steel wire with a tensile residual stress of 61 Kgf/mm ² was 100%.
It can be seen that the steel wire according to the invention exhibits excellent ductility. Further, the steel wire of the present invention has excellent corrosion fatigue properties and durability in tires. No. 3 has a wire diameter of 2.6 mm and a tensile strength of 168 Kgf/mm ² and 50 Kg.
No. 4 is a steel wire with a compressive residual stress of f/ ^mm2 , and No. 4 is a steel wire with a wire diameter of 4.5mm, a tensile strength of 196Kgf/ ^mm2 , and a compressive residual stress of 83Kgf/ ^mm2 , both of which have abnormal rupture rates. is 0, indicating excellent ductility. Compressive residual stress was applied by shot peening in both cases. Nos. 5, 6, 7, and 8 all have a high abnormal rupture rate because their composition or residual stress is outside the scope of the present invention.
It is clear that it lacks ductility. Next, Nos. 9 to 27 are related to invention 2, of which
Nos. 9, 11, 12, 14, 15, 16, 19, and 20 are examples of the present invention, and the others are comparative examples. No.9 and 10 have a wire diameter of 0.25mm and a tensile strength of 286Kgf/mm ²
Results for steel wires with the same composition of
The abnormal rupture rate in the twist test of No. 9 steel wire with compressive residual stress of 87Kgf/ ^mm2 is 5%, while 45Kgf/ ^mm2
The abnormal rupture rate of No. 10 steel wire having a tensile residual stress of 95% indicates that the steel wire of the present invention has extremely excellent ductility. Note that the compressive residual stress was imparted by roller rolling. No. 11 has a wire diameter of 2.5 mm and a tensile strength of 205 Kgf/mm ² , 60
Results for steel wire with compressive residual stress of Kgf/ ^mm2 ,
The abnormal rupture rate is 0 and it has excellent ductility. In this case, the compressive residual stress is imparted by shot peening. Nos. 12 and 13 are examples of steel wires with the same composition, wire diameter 0.6 mm, tensile strength 256 Kgf/mm ² , and 65 kg
No. 12 steel wire, which has a compressive residual stress of f/mm ² , has an abnormal rupture rate of 5%, whereas it has a compressive residual stress of 130Kgf/mm ²
In steel wire No. 13, which had a compressive residual stress of 70%, the abnormal rupture rate reached 70%, and it is clear that the steel wire of the present invention has excellent ductility. The compressive residual stress in this case was imparted by roller rolling. No.14 has a wire diameter of 4.5 mm, a tensile strength of 195 Kgf/mm ^2, and a weight of 45 kg.
Steel wire with compressive residual stress of f/mm ² , No.15 is wire diameter
The results are for a galvanized steel wire of 3.2 mm, tensile strength of 170 Kgf/mm ² , and compressive residual stress of 41 Kgf/mm ² , both of which have an abnormal rupture rate of 0 and excellent ductility. The compressive residual stress was given to the No. 14 steel wire by roller rolling, and the No. 15 steel wire was given by shot peening. Nos. 16 to 18 are results for steel wires with the same composition, wire diameter 8 mm, tensile strength 152 Kgf/mm ² , and 41 Kg
No. 16, which has a compressive residual stress of f/mm ² , has an abnormal rupture rate of 5%, and No. 17, which has a tensile residual stress of 25 Kgf/mm ² , and only has a compressive residual stress of 18 Kgf/mm ² . For No. 18 steel wire, the abnormal rupture rate is 60%.
It can be seen that the steel wire of the present invention has excellent ductility. Here, compressive residual stress was applied to the No. 16 steel wire by shot peening, and to the No. 18 steel wire by roller ductility processing. Further, the steel wire according to the present invention has excellent settability and delayed fracture properties. No. 19 has a wire diameter of 1.2 mm and a tensile strength of 220 Kgf/mm ² , 78
Steel wire with compressive residual stress of Kgf/ ^mm2 , also No.20
wire diameter is 3.6mm, tensile strength is 184Kgf/mm ² and 50Kgf/mm ²
The abnormal rupture rates are 5% and 0, respectively, indicating excellent ductility. All of these were given compressive residual stress by roller rolling. Nos. 21 to 27 each have a steel wire composition or residual stress outside the scope of the present invention, and therefore all have a high abnormal rupture rate and poor ductility. Nos. 28 to 42 relate to Invention 3, of which No.
28, 29, 30, 32, 33, 35, 36 are examples of the present invention,
The others are comparative examples. First, No. 28 has a wire diameter of 2.0 mm and a tensile strength of 196 Kgf/mm ²
steel wire with compressive residual stress of 60Kgf/ ^mm2 , and
No.29 has a wire diameter of 0.8mm and a tensile strength of 258Kgf/mm ² and 72Kg.
The results are for steel wires with a compressive residual stress of f/mm ² , and the abnormal rupture rates are 0 and 5%, respectively, indicating excellent ductility. No.30 and 31 have a wire diameter of 0.06mm and a tensile strength of 408Kgf/mm ²
The results are for steel wires with the same composition of 76Kgf/
The abnormal rupture rate of No. 30 steel wire with a compressive residual stress of mm ² is 5%, while the abnormal rupture rate of No. 31 steel wire with a tensile residual stress of 50 Kgf/mm ² is 100%. %
It can be seen that the steel wire of the present invention has excellent ductility. It is also clear that the steel wire reinforced plastic sheet according to the invention exhibits excellent fatigue properties. The compressive residual stress was applied by roller rolling. No.32 has a wire diameter of 5.5mm, a tensile strength of 185Kgf/ ^mm2, and a weight of 65Kg.
The results show that the steel wire has a compressive residual stress of f/mm ² , has an abnormal rupture rate of 0, and has excellent ductility. Nos. 33 and 34 are results for steel wires of the same composition with a wire diameter of 3.2 mm and a tensile strength of 146 Kgf/mm ² .
Steel wire No. 33, which has a compressive residual stress of 45 Kgf/mm ² , has an abnormal rupture rate of 0, whereas steel wire No. 34, which has an excessive compressive residual stress of 93 Kgf/mm ² , has an abnormal rupture rate. It can be seen that the steel wire of the present invention has excellent ductility with a ratio of 35%. No. 35 has a wire diameter of 3.2 mm and a tensile strength of 170 Kgf/mm ² .
Steel wire with compressive residual stress of Kgf/ ^mm2 , also No.36
wire diameter is 0.3mm, tensile strength is 238Kgf/mm ² and 69Kgf/mm ²
In this example, the abnormal rupture rates are 0 and 5%, respectively, and both exhibit excellent ductility. The compressive residual stress in steel wires No. 32, 33, 35, and 36 was applied by shot peening. On the other hand, in Nos. 37 to 42, the composition or residual stress of the steel wires is outside the scope of the present invention, so all have high abnormal rupture rates and lack ductility. Finally, Nos. 43 to 55 relate to Invention 4, among which Nos. 43, 44, 45, 46, 47, and 49 are examples of the present invention, and the others are comparative examples. No. 43 is a steel wire with a wire diameter of 2.0 mm, a tensile strength of 195 Kgf/mm ² and a compressive residual stress of 75 Kgf/mm ² , and No. 44 is a steel wire with a wire diameter of 2.0 mm.
3.6mm, tensile strength 185Kgf/ ^mm2 , and compressive residual stress of 50Kgf/ ^mm2 Steel wire No. 45 has a wire diameter of 1.2mm, tensile strength 221Kgf/ ^mm2 , and compressive residual stress 40Kgf/ ^mm2
and No. 46 has a wire diameter of 0.35 mm and a tensile strength of
The steel wire has a compressive residual stress of 260Kgf/mm ² and 80Kgf/mm ² , and both have extremely high ductility with an abnormal rupture rate of 0. No.47 and 48 have a wire diameter of 3.6mm and a tensile strength of 228Kgf/mm ²
The results are for steel wires with the same composition of 63Kgf/
Steel wire No. 47, which has a compressive residual stress of mm ² , has an abnormal rupture rate of 0 and excellent ductility. On the other hand, No. 48 steel wire with a tensile residual stress of 30 Kgf/mm ² has an abnormal rupture rate of 75%.
and lacks ductility. Further, the steel wire No. 47 of the present invention has excellent stress corrosion cracking properties, and ropes manufactured from this steel wire exhibit excellent fatigue properties. In addition, compressive residual stress was applied to steel wires No. 43, 44, 45, 46, and 47 by roller rolling. No.49 and 50 have a wire diameter of 0.6mm and a tensile strength of 290Kgf/mm ²
The results are for steel wires with the same composition of 86Kgf/
The No. 49 steel wire has a compressive residual stress of mm ² and has an abnormal rupture rate of 0 and excellent ductility. On the other hand, steel wire No. 50 having a tensile residual stress of 43 Kgf/mm ² showed an abnormal fracture rate of as much as 90%, and it is clear that the wire had poor ductility. This steel wire also has excellent fatigue properties. The compressive residual stress of steel wire No. 49 was given by shot peening. Nos. 51 to 55 had a composition or residual stress outside the scope of the present invention, and therefore had a high abnormal rupture rate and poor ductility.

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Claims (1)

[Claims] 1. C0.4 to 1.0%, Si 2.0% or less, Mn 0.2 by weight
Contains ~2%, P0.02% or less, S0.02% or less,
N is limited to 0.01% or less, the remainder consists of iron and unavoidable impurities, and has a strength of 130Kgf/mm ² or more, and according to the steel wire strength σ (0.05σ + 23)
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of ~(0.35σ+28) Kgf/mm ² . 2 Weight%: C0.4-1.0%, Si2.0% or less, Mn0.2
Contains ~2%, P0.02% or less, S0.02% or less,
Limited to N0.01% or less, and Cr0.05-3%,
Mo0.01~1%, W0.01~1%, Cu0.05~3%,
Contains one or more of Ni0.1-5% and Co0.1-5%, with the balance consisting of iron and unavoidable impurities, and has a strength of 130Kgf/mm2 or ^more , depending on the steel wire strength σ. (0.05σ+23)～(0.35σ+28)Kg
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of f/mm ² . 3 Weight% C0.4-1.0%, Si2.0% or less, Mn0.2
Contains ~2%, P0.02% or less, S0.02% or less,
Limit N to 0.01% or less, and Al0.001 to 0.1%,
Ti0.001~0.1%, Nb0.001~0.1%, V0.001~0.1
%, B0.0003~0.05%, Mg0.001~0.1%, the balance consists of iron and unavoidable impurities, and has a strength of 130Kgf/mm2 or ^more , and has a steel wire strength σ Depending on (0.05σ+23)~
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of (0.35σ+28) Kgf/mm ² . 4 Weight%: C0.4-1.0%, Si2.0% or less, Mn0.2
Contains ~2%, P0.02% or less, S0.02% or less,
Limited to N0.01% or less, and Cr0.05-3%,
N0.01~1%, W0.01~1%, Cu0.05~3%,
Contains one or more of Ni0.1-5%, Co0.1-5%, and further Al0.001-0.1%, Ti0.001-0.1%,
Nb0.001~0.1%, V0.001~0.1%, B0.0003~0.05
%, Mg0.001 to 0.1%, the balance consists of iron and inevitable impurities, and
It has a strength of 130Kgf/mm ² or more, and depending on the steel wire strength σ (0.05σ+23) to (0.35σ+28)Kg
A high tensile strength steel wire with excellent ductility, characterized by having a surface compressive residual stress of f/mm ² .