JP3175551B2 - Manufacturing method of non-magnetic welded wire mesh - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a non-magnetic welded wire mesh, and more particularly to a concrete structure such as a subgrade of a linear motor car or a compass check apron at an airport, and a high Mn steel non-metal used for reinforcing the same. The present invention relates to a method for producing a magnetic welded wire mesh using a hot-rolled steel wire.

[0002]

2. Description of the Related Art Structural components such as the subgrade of a linear motor car and a fusion reactor can be used to prevent magnetization and heat generation in a high magnetic field, and the compass check apron at airports can check the compass of an aircraft. Therefore, a non-magnetic steel material having a low magnetic permeability is used. Among such non-magnetic structural members, the materials of the welding wire mesh used for concrete structures and for reinforcement include austenitic stainless steel such as SUS304 of JIS and S
High Mn steels called so-called "Hadfield steels" such as CMnH2 have been used.

[0003] However, austenitic stainless steel is expensive because it contains a large amount of expensive Ni or Cr, and has a problem that the size (diameter) of the material must be increased because the yield point is low. . In addition, enlarging the size has caused a further increase in cost.

On the other hand, high Mn steels exhibit high strength and stable non-magnetism, and are less expensive than austenitic stainless steels. However, since there is a problem in terms of weldability, reinforcement and bundling are performed manually, which requires a great deal of cost for construction.

As a method for manufacturing a high Mn steel wire mesh, Japanese Patent Publication No. 60-40498 proposes a method for manufacturing a crimped wire mesh in which a high Mn steel wire is bent into a wavy shape and then knitted between the wavy portions. . However, the bonding strength of the wire mesh manufactured by this method is low and cannot be used for concrete structures and reinforcement.

On the other hand, Japanese Patent Publication No. 57-40901 proposes a "non-magnetic high manganese steel excellent in weldability and machinability" containing 0.3 to 3.0% by weight of Ni. However, even if the high-Mn steel proposed in the above-mentioned publication is used as a material, the hot-rolled steel wires are arranged in a mesh form, and the intersections thereof are simply subjected to electric resistance welding, so that the welding points can be separated or joined. Also, the bonding strength was low. This is because oxides generated by hot rolling (hereinafter, also referred to as “scale”) deteriorate the bondability during electric resistance welding.

That is, FeO, Fe ₂ O ₃ , and Fe ₃ O ₄ oxides are formed on the surface of the hot-rolled steel material.
In the case of steel, in addition to these, a high melting point Mn oxide is simultaneously generated, which deteriorates the joinability during electric resistance welding. Therefore, in order to provide sufficient joining strength by electric resistance welding, it is necessary to remove hot-rolled high Mn steel wire by peeling or pickling to remove scale, especially high melting point Mn oxide. is there. However, in this case, the manufacturing process is complicated, and the cost is further increased.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a concrete structure such as a subgrade of a linear motor car or a compass check apron at an airport or a joint used for reinforcing the same. It is an object of the present invention to provide a method for manufacturing a high strength non-magnetic welded metal mesh made of high Mn steel at low cost by using a steel wire as hot rolled.

[0009]

The present inventor has made various studies to solve the above-mentioned problems, and as a result, has obtained the following findings.

(A) C: 0.10-1.5% by weight
%, Mn: especially the material surface in the hot rolling at a high Mn steel containing 5 to 30% Mn oxides having a high melting point is FeO, Fe ₂ O
_{3) The} amount produced simultaneously with Fe ₃ O ₄ is increased, and the joinability by electric resistance welding is significantly deteriorated.

(B) High M generated at a temperature of 950 ° C. or higher
Since the scale of n steel has poor adhesion to the steel material, it is easily peeled. Above all, a scale formed at a temperature of 950 ° C. or more and having a thickness of 10 μm or more peels off very easily.

(C) At least the scale of the coil surface
If about 80% peels off, sufficient contact by electric resistance welding
A joint strength is obtained.

(D) Therefore, high-Mn steel is hot-rolled to 9
A film with a thickness of 10 μm or more wound in a coil at 50 ° C. or more
If the high-Mn steel wire rod with scale is straightened next, the scale on the coil surface will be compressed and stretched during straightening, so the scale will crack and peel off easily, and the jointability by electric resistance welding will be improved. improves.

(E) High Mn steel is hot-rolled to 950 ° C.
After winding at the above temperature, 3
When cooled to a temperature in the temperature range of 00 ° C. or less, carbides do not precipitate at the crystal grain boundaries, so that extremely good strength and toughness are exhibited even in hot rolling.

The present invention based on the above findings provides the following (1) to
The gist is the method of manufacturing a nonmagnetic welded wire mesh of (4).

(1) C: 0.10-1.5% by weight
%, Mn: 10 [mu] on the surface Tsu winding into a coil high Mn steel is rolled to 950 ° C. above the temperature at hot containing 5-30%
m high-Mn steel wire rod with a thickness of at least m
After straightening in a temperature range of 500 ° C or less and scale
A method for producing a nonmagnetic welded metal net, comprising: arranging at least about 80% of the steel wire , and then straightening a straightened high Mn steel wire in a mesh shape, and intersections thereof are subjected to electric resistance welding.

(2) C: 0.10 to 1.5% by weight
%, Mn: 5 μm to 30% on a surface which is hot-rolled and coiled at a temperature of 950 ° C. or more.
m high-Mn steel wire rod with a thickness of at least m
5 ° C. / sec is cooled to a temperature of a temperature region of 300 ° C. or less in the above cooling rate, is peeled off at least about 80% of the scale corrected linearly thereafter 500 ° C. below the temperature range after Ri
And then straightening the straightened high-Mn steel wires in a mesh form, and welding the intersections thereof by electric resistance welding.

(3) The method for producing a non-magnetic welded mesh according to any one of the above (1) and (2), wherein the high Mn steel contains 3 to 6% by weight of Cr and further contains 3 to 6% by weight of Cr.

(4) The above (1) to (3), wherein the high Mn steel contains V in an amount of 0.1 to 1.0% by weight.
The method for producing a nonmagnetic welded wire mesh according to any one of the above.

Here, to arrange the high Mn steel wires in a mesh shape means to arrange the high Mn steel wires orthogonally and geometrically as defined in JIS G 3551.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Each requirement of the present invention will be described in detail below. "%" Of the component content means "% by weight".

(A) Chemical composition of high Mn steel to be treated C: C is an element effective for stabilizing the austenite structure of the steel and making it non-magnetic. However, its content is 0.10%
If it is less than 1.5%, the desired effect cannot be obtained, and if it exceeds 1.5%, the workability during hot and cold working deteriorates. Therefore, the content of C in the high Mn steel according to the present invention is 0.10 to 0.10.
1.5%.

Mn: Mn is an element necessary for keeping steel in a non-magnetic state.
However, if the content is less than 5%, a stable non-magnetic state cannot be obtained, and if it exceeds 30%, the cost for steelmaking will increase significantly. Therefore, the content of Mn is set to 5 to 30%.

The high Mn steel to which the method of the present invention is directed may further contain one or more of Cr and V in addition to the above components. The effects and desirable contents of these alloy elements are as follows.

Cr: Since Cr has the effect of increasing the strength and corrosion resistance of high Mn steel, it is contained for the purpose of securing large strength and corrosion resistance, particularly in the case of a nuclear fusion experimental structure requiring earthquake resistance.
If the content is less than 3%, the effect cannot be obtained. On the other hand, if the content exceeds 6%, the cost is greatly increased and the economy is deteriorated. Therefore, when Cr is contained, the content is preferably set to 3 to 6%. In the case of high Mn steel, Cr of a maximum of about 0.2% is usually mixed as an impurity from the raw material.

V: Since V has the effect of increasing the strength, it is included for the purpose of ensuring high strength, particularly in the case of a reinforcing rod for a running path of a linear motor car, but if less than 0.1%, the effect cannot be obtained. On the other hand, if the content exceeds 1.0%, the strength improving effect is saturated and the cost is increased. Therefore, when V is contained, the content is preferably 0.1 to 1.0%.

It should be noted that the high Mn steels targeted by the method of the present invention may contain other chemical components as long as the required properties can be imparted to the welded wire mesh as the final product. No problem.

Specifically, for example, C, Mn, Cr and V
Besides, Ni: 0.1 to 10%, N: 0.010 to
0.10%, Cu: 0.1-3%, Mo: 0.1-3%
May be used as the high Mn steel. Further, impurities such as P and S may be included.

(B) Winding in hot rolling The winding temperature in hot rolling is 950 ° C. or higher , and
If the thickness of the kale is 10 μm or more, the force by bending and elongation when straightening the coil into a straight line (without peeling or pickling the coil before electric resistance welding to produce a welded wire mesh) ( The scale on the surface of the material (coil) can be peeled off only by the compression force and the tension force).
This is because even if the thickness of the scale is thin, the material and by the adhesion is too good scale corrected linearly scales have difficulty peeled
It is pressurized, et al.

At least 80% of the scale on the coil surface
If the degree of separation is sufficient, sufficient joining strength can be obtained by electric resistance welding.

By the way, the thickness formed at a high temperature is 10 μm
As described above, the above scale can be peeled off only by the force of bending and elongation when the coil is straightened straight, but it is preferable to suppress the thickness of the scale to 20 μm or less in order to increase the product yield. . When the winding temperature exceeds 1150 ° C., the thickness of the scale increases to exceed 20 μm. Therefore, the upper limit of the coiling temperature in hot rolling is preferably about 1150 ° C.

(C) In order to easily peel off a scale having a straightened thickness of 10 μm or more after straightening after winding, and to prevent the formation of a thin scale having good adhesion to the coil during straightening. 50 for straightening
It may be performed in a temperature range of 0 ° C. or lower, preferably in a temperature range of 300 ° C. or lower. The lower limit of the correction temperature does not need to be particularly limited, but may be about room temperature as the lower limit temperature in terms of equipment maintenance.

By using the spinner straightening device 3 shown in FIG. 1, for example, by twisting the material, the scale peeling rate can be further increased. By the way, the spinner straightening device 3 is a device for straightening a material by bending while simultaneously twisting the material as shown in FIG.

As already mentioned, at least 80% of the scale produced by hot rolling in the straightening described above.
%, Sufficient bonding strength can be obtained by electric resistance welding.

(D) Cooling after winding After winding into a coil at a temperature of 950 ° C. or more, and cooling to a temperature of 300 ° C. or less at a cooling rate of 5 ° C./sec or more, crystal grain boundaries are obtained. High Mn showing very good strength and toughness even in hot rolling as carbides do not precipitate in
A steel wire of steel is obtained. Therefore, when it is desired to provide the welded wire net as a final product with good strength and toughness, it is better to perform cooling after winding in a coil shape under the above conditions.

The lower limit of the temperature at which the cooling is performed at the above-described cooling rate is not particularly limited, and may be the lower limit generated from the viewpoint of the cooling medium and the cooling equipment.

Hereinafter, the method of the present invention will be described in more detail by way of examples.

[0038]

EXAMPLE A high Mn steel having the chemical composition shown in Table 1 was smelted by a conventional method and then slab-rolled into billets.

Example 1 The above billet of the high Mn steel A shown in Table 1 was heated to 1200 ° C., rolled into a wire having a diameter of 8 mm by a usual method, and wound into a coil at 1050 to 900 ° C. Thereafter, the mixture was cooled to about 150 ° C. at a cooling rate of 5 ° C./sec by a Stealmore air cooling device, and further cooled to room temperature.

The coil 1 of the high Mn steel A thus obtained
Was straightened through a straightening roller 2 and a spinner straightening device 3 as shown in FIG. 1 and cut into short strands 5 by a cut shear 4. In FIG. 1, an arrow 3a in the spinner correction device 3 indicates a bending force.

Next, the surface scale condition of the wire 5 was compared with the surface scale condition of the coil 1 before straightening the surface scale condition of the wire 5 by visual observation. As a result, the descaled rate is
When the winding temperature is 1050 ° C., 90% or more, 1000
About 85% at ℃, about 80% at 950 ° C,
At 900 ° C., it was 60 to 70%.

Thereafter, as shown in FIG. 2, using the element wires 5 manufactured under the above-described conditions, five vertical wires 5a and ten horizontal wires 5b form a welded wire mesh (width 1300 mm × length 2800 m).
m) was prepared one sheet at a time for each condition. The electric resistance welding was performed under the same conditions as those of ordinary WFR welded wire mesh (JIS G 3551).

After the welding wire mesh was prepared, the welding point 6 was visually observed.
Was removed, and a portion not joined (peeled portion at welding point 6) was examined. As a result, the winding temperature was 1050, 1000 ° C.
In the case of, there is no peeling of welding point 6, and JIS G 35
The welding point shear strength determined according to No. 51 is 160 to 2 respectively.
It was 20 MPa and 150 to 200 MPa. Furthermore,
The 0.2% proof stresses are 410 to 430 MPa and 450, respectively.
~ 480MPa, tensile strength is 800 ~ 820 each
MPa, 840-860MPa, elongation is 30-
35% and 34-38%.

On the other hand, when the winding temperature was 950 ° C. and 900 ° C., peeling of the welding point 6 was observed at a ratio of 1 place / sheet and 3 places / sheet, respectively. In addition, the shear strength at the welding point determined according to JIS G 3551 is 130 to 150M, respectively.
Pa and 80 to 100 MPa. Furthermore, 0.2% proof stress is 500-510MPa, 540-550M, respectively.
In Pa, the tensile strength is 860-870 MPa, 8
80-890MPa, elongation is 28-30% and 2 respectively
5-26%.

That is, the nonmagnetic welded wire mesh manufactured by the method of the present invention has a high joining strength, and its mechanical properties are JIS G 35
It satisfies the standard value of 51.

Example 2 The above billet of high Mn steel B shown in Table 1 was heated to 1200 ° C., and a deformed steel bar having a nominal size of D13 according to JIS G 3112 was coiled at 1050 ° C. by a usual method. And rolled into a burn-in coil and allowed to cool to room temperature.

The "bar-in coil" is obtained by winding a steel bar into a coil shape in the same manner as a wire rod with a winding machine for the purpose of improving the yield and the processing efficiency, and thereafter continuously drawing or linear processing. It is said that the steel bar goes.

The burn-in coil of the high Mn steel B obtained as described above is straightened through the straightening roller 2 and the spinner straightening device 3 in the same manner as in the first embodiment.
It was cut into short strands 5 by a cut shear 4 (see FIG. 1).

Thereafter, as shown in FIG. 2, ten welded wire meshes (width 1300 mm × length 2800 mm) having five vertical lines 5 a and ten horizontal lines 5 b were prepared using the above-mentioned strands 5. The electric resistance welding was performed under the same conditions as those of a normal WFR welding mesh.

After the welding wire mesh has been prepared, the welding point 6 is visually observed.
Was inspected at the peeling point. As a result, there was no peeling at the welding point 6, and the shear strength at the welding point determined according to JIS G 3112 was 150 to 180 MPa. Further, the 0.2% proof stress is 500 to 520 MPa, and the tensile strength is 900 to 92 MPa.
0 MPa, elongation was 40 to 42%.

That is, the nonmagnetic welded wire mesh produced by the method of the present invention has a high joining strength, and its mechanical properties are JIS G 35
It satisfies the standard value of 51.

Example 3 The billet of the high Mn steel C shown in Table 1 was heated to 1200 ° C., and a deformed steel bar having a nominal size of D12 conforming to JIS G 3112 was coiled at 1000 ° C. by a usual method. And rolled into a burn-in coil.
It was air-cooled at a cooling rate of 0 ° C./min, and then allowed to cool.

Next, as in Example 2, the sheet was straightened through a straightening roller 2 and a spinner straightening device 3 and cut into short strands 5 by a cut shear 4 (see FIG. 1).

Thereafter, as shown in FIG. 2, ten welded wire meshes (width 1300 mm × length 2800 mm) having five vertical lines 5 a and ten horizontal lines 5 b were prepared using the above-mentioned strands 5. The electric resistance welding was performed under the same conditions as those of a normal WFR welding mesh.

After the welding wire mesh was prepared, the welding point 6 was visually observed.
Was inspected at the peeling point. As a result, there was no peeling at the welding point 6, and the shear strength at the welding point determined according to JIS G 3112 was 150 to 180 MPa. Further, the 0.2% proof stress is 550 to 560 MPa, and the tensile strength is 860 to 87.
0 MPa, elongation was 38-40%.

That is, the nonmagnetic welded wire mesh produced by the method of the present invention has a high joining strength, and its mechanical properties are JIS G 35
It satisfies the standard value of 51.

[0057]

[Table 1]

[0058]

As described above, according to the method for producing a non-magnetic welded wire mesh of the present invention, a non-magnetic welded wire mesh having high joining strength is produced at low cost using a high Mn steel wire as hot rolled. Therefore, the industrial effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a view showing a method for straightening a high Mn steel coil in an example.

FIG. 2 is a diagram showing a welded wire mesh produced in an example.

[Explanation of symbols]

1: coil, 2: straightening roller, 3: spinner straightening device, 3a: bending force, 4: cut shear, 5:
Element wire, 5a: vertical line, 5b: horizontal line, 6: welding point,

Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C22C 38/00 302 C22C 38/00 302Z 38/04 38/04 38/24 38/24 (56) References JP-A-63-259022 (JP) JP-A-61-84324 (JP, A) JP-A-61-37953 (JP, A) JP-B-63-19252 (JP, B2) JP-B-55-39619 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21F 27/10 B21F 1/02 C21D 8/06 C22C 38/00 B23K 11/14 B23K 11/16

Claims (4)

(57) [Claims] (1) C: 0.10 to 1.5% by weight, M
n: High Mn steel containing 5 to 30% is hot rolled to 950
10μm or more surface Tsu winding coiled ℃ temperatures above
After winding, a high Mn steel wire having a thickness scale of
Straighten in a temperature range of 00 ° C or less to reduce the scale.
A method for producing a non-magnetic welded wire mesh, characterized in that at least about 80% is peeled off, then straightened straight high Mn steel wires are arranged in a mesh form, and their intersections are subjected to electric resistance welding. 2. C: 0.10-1.5% by weight, M
n: High Mn steel containing 5 to 30% is hot rolled to 950
10μm or more on coiled surface at a temperature of ℃ or more
After winding, a high Mn steel wire having a thickness scale of
Cooling to a temperature in the temperature range of 300 ° C. or less at a cooling rate of at least 300 ° C./sec, and then straightening in a temperature range of 500 ° C. or less to peel off at least about 80% of the scale , A method for manufacturing a non-magnetic welded wire mesh, comprising arranging high Mn steel wires in a mesh shape, and performing electrical resistance welding at their intersections. 3. The steel according to claim 1, wherein the high Mn steel is in weight% and the Cr content is 3 to 6%.
The method for producing a nonmagnetic welded wire mesh according to any one of claims 1 and 2, wherein 4. The steel according to claim 1, wherein the content of the high Mn steel is% by weight, and
The method for producing a non-magnetic welded wire net according to any one of claims 1 to 3, wherein the wire mesh contains 1.0%.