KR20240014501A - Continuous annealing device and continuous hot dip galvanizing device, and manufacturing method of steel sheet - Google Patents

Abstract

A continuous annealing device capable of producing steel sheets with excellent hydrogen embrittlement resistance is provided. The continuous annealing device 100 of the present invention includes a pay-off reel 10 for dispensing cold-rolled steel sheet S from a cold-rolled coil C, and an annealing furnace 20 for continuously annealing the cold-rolled steel sheet S. , a heating zone 22, a cracking zone 24, and a cooling zone 26 are located from the upstream side in the sheet-through direction, and in the heating zone 22 and the cracking zone 24, the cold-rolled steel sheet (S) is heated in a reducing atmosphere containing hydrogen. an annealing furnace (20) that cools the cold-rolled steel sheet (S) in the cooling zone (26), and a downstream facility (30) that continuously distributes the cold-rolled steel sheet (S) discharged from the annealing furnace (20), Regarding the tension reel 50 for winding the cold-rolled steel sheet (S) being sold through the downstream facility 30, and the cold-rolled steel sheet (S) being sold from the cooling stand 26 to the tension reel 50, the cold-rolled steel sheet It has a vibration adding device 60 or 70 that adds vibration so that the frequency of vibration is 100 Hz or more and 100,000 Hz or less, and the maximum amplitude of the cold rolled steel sheet is 10 nm or more and 500 μm or less.

Description

Continuous annealing device and continuous hot dip galvanizing device, and manufacturing method of steel sheet

The present invention relates to a continuous annealing device, a continuous hot dip galvanizing device, and a method of manufacturing a steel sheet. The present invention is particularly suitable for use in the fields of automobiles, home appliances, and building materials, and provides a continuous annealing device and a continuous hot-dip galvanizing device for producing a steel sheet with excellent hydrogen embrittlement resistance and a small amount of hydrogen inherent in the steel; And it is about the manufacturing method of steel plates.

For example, when manufacturing annealed steel sheets and hot-dip galvanized steel sheets using a continuous annealing device and a continuous hot-dip galvanizing device, the steel sheets are annealed in a reducing atmosphere containing hydrogen, so hydrogen is contained in the steel sheets during this annealing. invades. Hydrogen inherent in the steel sheet reduces formability such as ductility, bendability, and stretch flangeability of the steel sheet. Additionally, hydrogen inherent in the steel sheet can embrittle the steel sheet and cause delayed fracture. Therefore, treatment to reduce the amount of hydrogen in the steel sheet is required.

For example, the amount of hydrogen in steel can be reduced by leaving the product coil produced by a continuous annealing device or a continuous hot-dip galvanizing device at room temperature. However, at room temperature, it takes time for hydrogen to move from the inside of the steel sheet to the surface and desorb from the surface, so to sufficiently reduce the amount of hydrogen in the steel, it requires standing for several weeks or more. Therefore, the space and time required for such dehydrogenation treatment become problems in the manufacturing process.

In addition, Patent Document 1 states that the amount of hydrogen in steel is reduced by maintaining an annealed steel sheet, hot-dip galvanized steel sheet, or alloyed hot-dip galvanized steel sheet for 1800 seconds or more and 43200 seconds or less within a temperature range of 50°C to 300°C. A method for doing so is disclosed.

International Publication No. 2019/188642

However, in Patent Document 1, there are concerns about changes in mechanical properties such as an increase in yield strength and temper embrittlement due to structural changes due to heating.

Therefore, in view of the above problems, the present invention provides a continuous annealing device and a continuous hot-dip galvanizing device capable of producing a steel sheet with excellent hydrogen embrittlement resistance without impairing production efficiency or changing mechanical properties, and a steel sheet. The purpose is to provide a manufacturing method.

In order to solve the above problems, the present inventors have conducted extensive research and discovered the following points. That is, in a continuous annealing line (CAL) or a continuous hot-dip galvanizing line (CGL), a steel sheet is annealed in a reducing atmosphere containing hydrogen, and then the steel sheet is heated from the annealing temperature to room temperature. It was found that hydrogen in the steel sheet could be sufficiently and efficiently reduced by continuously adding vibration of a predetermined frequency and maximum amplitude to the steel sheet being rolled during the cooling process. Specifically, it was found that hydrogen in the steel sheet could be sufficiently and efficiently reduced by micro-vibrating the steel sheet at a high frequency and small maximum amplitude. This is presumed to be due to the following mechanism. By forcibly and slightly vibrating the steel sheet, bending deformation is repeatedly applied to the steel sheet. As a result, the lattice spacing on the surface is expanded compared to the center of the thickness of the steel plate. Hydrogen in the steel sheet diffuses toward the surface of the steel sheet with a wide lattice spacing and low potential energy, and is desorbed from the surface.

That is, the present invention was made based on the above knowledge, and the gist of it is as follows.

[1] A pay-off reel for dispensing cold-rolled steel sheet from a cold-rolled coil,

An annealing furnace for continuously annealing the cold-rolled steel sheet by rolling it, wherein a heating zone, a cracking zone, and a cooling zone are located from the upstream side in the rolling direction, and in the heating zone and the cracking zone, the cold-rolled steel sheet is annealed in a reducing atmosphere containing hydrogen, In the cooling zone, an annealing furnace for cooling the cold rolled steel sheet,

a downstream facility that continuously distributes the cold rolled steel sheet discharged from the annealing furnace;

a tension reel for winding the cold rolled steel sheet being sold to the downstream facility;

For the cold-rolled steel sheet being sold from the cooling table to the tension reel, the frequency of vibration of the cold-rolled steel sheet is 100 Hz or more and 100,000 Hz or less, and the maximum amplitude of the cold-rolled steel sheet is 10 nm or more and 500 ㎛ or less. A continuous annealing device having a vibration adding device that preferably adds vibration.

[2] The continuous annealing device according to [1] above, wherein the vibration adding device is installed on the cooling table.

[3] The continuous annealing device according to [1] or [2] above, wherein the vibration adding device is installed in a position where vibration can be applied to the cold rolled steel sheet being passed through the downstream facility.

[4] The arrangement of the vibration adding device and the sheet-threading speed of the cold-rolled steel sheet are set so that the time for adding vibration to the cold-rolled steel sheet is 1 second or more, according to any one of [1] to [3] above. Continuous annealing device.

[5] The vibration adding device has an electromagnet having opposite pole surfaces spaced apart from the surface of the cold rolled steel sheet, and is configured to cause the cold rolled steel sheet to vibrate due to an external force applied to the cold rolled steel sheet by the electromagnet. The continuous annealing device according to any one of 1] to [4].

[6] The continuous annealing device according to any one of [1] to [4] above, wherein the vibration adding device has a vibrator in contact with the cold-rolled steel sheet, and is configured to cause the cold-rolled steel sheet to vibrate by the vibrator.

[7] The continuous annealing device according to [1] above,

The downstream equipment is located downstream of the annealing furnace in the plate-making direction, and has a hot-dip galvanizing bath for immersing the cold-rolled steel sheet and performing hot-dip galvanizing on the cold-rolled steel sheet. A continuous hot-dip galvanizing device.

[8] The continuous hot-dip galvanizing device according to [7] above, wherein the vibration adding device is installed at a position capable of adding vibration to the cold-rolled steel sheet being passed upstream of the hot-dip galvanizing bath.

[9] The continuous hot-dip galvanizing device according to [7] or [8] above, wherein the vibration adding device is installed in a position where vibration can be applied to the cold-rolled steel sheet being passed downstream from the hot-dip galvanizing bath.

[10] Continuous hot dip galvanizing according to [7] above, wherein the downstream equipment is located downstream in the sheet-through direction of the hot-dip galvanizing bath and has an alloying furnace for sheeting the cold-rolled steel sheet and heat-alloying the hot-dip galvanizing. Device.

[11] The continuous hot-dip galvanizing device according to [10], wherein the vibration-applying device is installed at a position capable of adding vibration to the cold-rolled steel sheet being passed upstream of the hot-dip galvanizing bath.

[12] The continuous hot-dip galvanizing device according to [10] or [11], wherein the vibration-applying device is installed at a position capable of adding vibration to the cold-rolled steel sheet being passed downstream of the hot-dip galvanizing bath.

[13] The arrangement of the vibration adding device and the sheet-threading speed of the cold-rolled steel sheet are set so that the time for adding vibration to the cold-rolled steel sheet is 1 second or more, according to any one of [7] to [12] above. Continuous hot dip galvanizing equipment.

[14] The vibration adding device has an electromagnet having opposite pole surfaces spaced apart from the surface of the cold rolled steel sheet, and is configured to cause the cold rolled steel sheet to vibrate due to an external force applied to the cold rolled steel sheet by the electromagnet. 7] The continuous hot dip galvanizing device according to any one of [13].

[15] The continuous hot-dip galvanizing method according to any one of [7] to [13] above, wherein the vibration adding device has a vibrator in contact with the cold-rolled steel sheet, and is configured to cause the cold-rolled steel sheet to vibrate by the vibrator. Device.

[16] (A) A process of dispensing a cold-rolled steel sheet from a cold-rolled coil by a pay-off reel,

(B) The cold-rolled steel sheet is passed through an annealing furnace in which a heating zone, a cracking zone, and a cooling zone are located from the upstream side of the rolling direction, and (B-1) in the heating zone and the cracking zone, in a reducing atmosphere containing hydrogen. A process of annealing a cold-rolled steel sheet and (B-2) performing continuous annealing of cooling the cold-rolled steel sheet in the cooling zone;

(C) a process of continuously selling the cold rolled steel sheet discharged from the annealing furnace,

(D) winding up the cold rolled steel sheet with a tension reel and forming a product coil in this order,

After step (B-2) and before step (D), with respect to the cold rolled steel sheet being sold, the frequency of vibration of the cold rolled steel sheet is 100 Hz or more and 100,000 Hz or less, and the maximum frequency of the cold rolled steel sheet is 100,000 Hz or less. A method of manufacturing a steel sheet including a vibration addition process of adding vibration so that the amplitude is 10 nm or more and 500 μm or less.

[17] The method for manufacturing a steel sheet according to [16] above, wherein the vibration addition process is performed in process (B-2).

[18] The method for manufacturing a steel sheet according to [16] or [17] above, wherein the vibration addition process is performed in process (C).

[19] Process (C) includes the step of (C-1) immersing the cold-rolled steel sheet in a hot-dip galvanizing bath located downstream in the plate-feeding direction of the annealing furnace, and hot-dip galvanizing the cold-rolled steel sheet. , the method for manufacturing a steel plate described in [16] above.

[20] The method for manufacturing a steel plate according to [19], wherein the vibration addition process is performed before the process (C-1).

[21] The method for manufacturing a steel sheet according to [19] or [20] above, wherein the vibration addition process is performed after the process (C-1).

[22] In the step (C), following the step (C-1), (C-2) the cold-rolled steel sheet is passed through an alloying furnace located downstream in the pass-through direction of the hot-dip galvanizing bath, and the hot-dip zinc plating bath is passed through the cold-rolled steel sheet. The method for producing a steel sheet according to [19] above, including the step of heat alloying the plating.

[23] The method for manufacturing a steel plate according to [22], wherein the vibration addition process is performed before the process (C-1).

[24] The method for manufacturing a steel sheet according to [22] or [23] above, wherein the vibration addition process is performed after the process (C-1).

[25] The method for manufacturing a steel sheet according to any one of [16] to [24] above, wherein in the vibration addition step, the time for adding vibration to the cold rolled steel sheet is 1 second or more.

[26] In the vibration addition process, the cold-rolled steel sheet is vibrated by an external force applied to the cold-rolled steel sheet by an electromagnet having opposite pole surfaces spaced apart from the surface of the cold-rolled steel sheet, [16] to [25]. The method for manufacturing a steel plate according to any one of the above.

[27] In the vibration addition step, the cold-rolled steel sheet is vibrated by a vibrator in contact with the cold-rolled steel sheet.

[28] The method for producing a steel sheet according to any one of [16] to [27] above, wherein the cold rolled steel sheet is a high-strength steel sheet having a tensile strength of 590 MPa or more.

[29] The cold rolled steel sheet is expressed in mass%,

C: 0.030 to 0.800%,

Si: 0.01 to 3.00%,

Mn: 0.01 to 10.00%,

P: 0.001 to 0.100%,

S: 0.0001 to 0.0200%,

N: 0.0005 to 0.0100%, and

Al: Contains 0.001 to 2.000%,

The method for producing a steel sheet according to any one of [16] to [28] above, wherein the steel sheet has a composition with the balance consisting of Fe and inevitable impurities.

[30] The above component composition is further expressed in mass%,

Ti: 0.200% or less,

Nb: 0.200% or less,

V: 0.500% or less,

W: 0.500% or less,

B: 0.0050% or less,

Ni: 1.000% or less,

Cr: 1.000% or less,

Mo: 1.000% or less,

Cu: 1.000% or less,

Sn: 0.200% or less,

Sb: 0.200% or less,

Ta: 0.100% or less,

Ca: 0.0050% or less,

Mg: 0.0050% or less,

Zr: 0.1000% or less, and

REM: 0.0050% or less

The method for producing a steel sheet according to [29] above, containing at least one element selected from the group consisting of.

[31] The cold rolled steel sheet is expressed in mass%,

C: 0.001 to 0.400%,

Si: 0.01 to 2.00%,

Mn: 0.01 to 5.00%,

P: 0.001 to 0.100%,

S: 0.0001 to 0.0200%,

Cr: 9.0 to 28.0%,

Ni: 0.01 to 40.0%,

N: 0.0005 to 0.500%, and

Al: Contains 0.001 to 3.000%,

The method for producing a steel sheet according to any one of [16] to [27] above, which is a stainless steel sheet having a composition in which the balance consists of Fe and inevitable impurities.

[32] The above component composition is further expressed in mass%,

Ti: 0.500% or less,

Nb: 0.500% or less,

V: 0.500% or less,

W: 2.000% or less,

B: 0.0050% or less,

Mo: 2.000% or less,

Cu: 3.000% or less,

Sn: 0.500% or less,

Sb: 0.200% or less,

Ta: 0.100% or less,

Ca: 0.0050% or less,

Mg: 0.0050% or less,

Zr: 0.1000% or less, and

REM: 0.0050% or less

The method for producing a steel sheet according to [31] above, containing at least one element selected from the group consisting of.

[33] The method for manufacturing a steel sheet according to any one of [16] to [32] above, wherein the product coil has a diffusible hydrogen amount of 0.50 mass ppm or less.

According to the continuous annealing device, the continuous hot dip galvanizing device, and the steel sheet manufacturing method of the present invention, a steel sheet with excellent hydrogen embrittlement resistance can be manufactured without impairing production efficiency or changing mechanical properties.

Figure 1 is a schematic diagram of a continuous annealing apparatus 100 according to an embodiment of the present invention.
Figure 2 is a schematic diagram of a continuous hot dip galvanizing device 200 according to an embodiment of the present invention.
Figure 3 is a schematic diagram of a continuous hot dip galvanizing device 300 according to another embodiment of the present invention.
Fig. 4 is a schematic diagram showing the configuration of the vibration adding device 60 used in each embodiment of the present invention.
5 (A) and (B) schematically show an example of the installation mode of the electromagnet 63 of the vibration adding device 60 to the cold rolled steel sheet S in distribution in each embodiment of the present invention. It is a drawing.
Figures 6 (A) and (B) are diagrams schematically showing the generation mode of the magnetic field from the electromagnet 63 in each embodiment of the present invention.
Fig. 7A is a schematic diagram showing the configuration of the vibration adding device 70 used in each embodiment of the present invention.
FIG. 7B is a diagram schematically showing an example of an installation mode of the vibrator 72 of the vibration adding device 70 to the cold rolled steel sheet S being sold.
8 (A) and (B) are examples of the positional relationship between the cooling nozzle 26A and the vibration adding device 60 or 70 when the vibration adding device 60 or 70 is installed in the cooling table 26. This is a schematic diagram showing .

One embodiment of the present invention relates to a continuous annealing line (CAL), and another embodiment of the present invention relates to a continuous hot-dip galvanizing line (CGL).

The method for manufacturing a steel sheet according to an embodiment of the present invention is realized by a continuous annealing line (CAL) or a continuous hot-dip galvanizing line (CGL).

Referring to FIG. 1, a continuous annealing device (CAL) 100 according to the first embodiment of the present invention includes a pay-off reel 10 for dispensing a cold-rolled steel sheet (S) from a cold-rolled coil (C), and a cold-rolled steel sheet (CAL) 100. An annealing furnace (20) for continuously annealing the cold-rolled steel sheet (S) discharged from the annealing furnace (20), a downstream facility (30) for continuously annealing the cold-rolled steel sheet (S) discharged from the annealing furnace (20), and a cold-rolled steel plate (30) for continuously annealing the steel sheet (S). It has a tension reel 50 that winds the steel plate S to form a product coil P. In the annealing furnace 20, a heating zone 22, a cracking zone 24, and a cooling zone 26 are located from the upstream side in the sheet-through direction, and a reducing atmosphere containing hydrogen is present in the heating zone 22 and the cracking zone 24. The cold rolled steel sheet S is annealed, and the cold rolled steel sheet S is cooled in the cooling zone 26. In addition, the annealing furnace 20 of the CAL 100 preferably has an overaging treatment zone 28 downstream of the cooling zone 26, but it is not essential. In the overaging treatment zone 28, overaging treatment is performed on the cold rolled steel sheet S. In this embodiment, a product coil of cold rolled annealed steel sheet (CR) is manufactured by CAL (100).

Referring to FIG. 1, the method of manufacturing a steel sheet according to the first embodiment realized by the continuous annealing device (CAL) 100 is (A) cold-rolled steel sheet from the cold-rolled coil C by the pay-off reel 10. (Steel strip) A process of dispensing (S), and (B) a cold-rolled steel sheet ( S) is plated, and in the heating zone 22 and the cracking zone 24 (B-1), the cold rolled steel sheet S is annealed in a reducing atmosphere containing hydrogen, and in the cooling zone 26 (B-2) A process of cooling the cold-rolled steel sheet (S) and performing continuous annealing; (C) a process of continuously selling the cold-rolled steel sheet (S) discharged from the annealing furnace (20); (D) to the tension reel (50) The process of winding up the cold rolled steel sheet (S) to form a product coil (P) is carried out in this order. Additionally, in the continuous annealing process (B) using the annealing furnace 20 of CAL 100, (B-3) the cold rolled steel sheet (S ) It is desirable to carry out over-aging treatment, but this process is not required. This embodiment is a method of manufacturing a product coil of cold rolled annealed steel sheet (CR) by CAL (100).

Referring to FIG. 2, a continuous hot dip galvanizing device (CGL) 200 according to a second embodiment of the present invention includes a pay-off reel 10 for dispensing a cold rolled steel sheet S from a cold rolled coil C; An annealing furnace (20) for continuously annealing the cold-rolled steel sheet (S), a downstream facility (30) for continuously annealing the cold-rolled steel sheet (S) discharged from the annealing furnace (20), and a downstream facility (30) for continuously annealing the cold-rolled steel sheet (S). It has a tension reel (50) that winds the cold rolled steel sheet (S) in process to form a product coil (P). In the annealing furnace 20, a heating zone 22, a cracking zone 24, and a cooling zone 26 are located from the upstream side in the sheet-through direction, and a reducing atmosphere containing hydrogen is present in the heating zone 22 and the cracking zone 24. The cold rolled steel sheet S is annealed, and the cold rolled steel sheet S is cooled in the cooling zone 26. CGL 200 is the downstream facility 30, located downstream in the distribution direction of the annealing furnace 20, and is a hot-dip zinc machine that immerses the cold-rolled steel sheet S and performs hot-dip galvanization on the cold-rolled steel sheet S. It further has a plating bath 31 and an alloying furnace 33 located downstream in the sheet-through direction of the hot-dip galvanizing bath 31, which allows the cold-rolled steel sheet S to be sheet-rolled and heat-alloys the hot-dip galvanizing. In this embodiment, a product coil of alloyed hot-dip galvanized steel sheet (GA) in which the zinc plating layer is alloyed is manufactured by the CGL 200. In addition, when the steel sheet (S) is only passed through the alloying furnace 33 and heat alloying is not performed, a product coil of hot-dip galvanized steel sheet (GI) in which the zinc plating layer is not alloyed is manufactured.

Referring to Fig. 2, the method of manufacturing a steel sheet according to the second embodiment realized by the continuous hot dip galvanizing equipment (CGL) 200 is (A) forming a steel sheet from a cold rolled coil (C) by a pay-off reel (10). A process of dispensing a cold rolled steel sheet (steel strip) (S), and (B) cold rolling in an annealing furnace 20 where a heating zone 22, a cracking zone 24, and a cooling zone 26 are located from the upstream side in the sheet-rolling direction. The steel sheet (S) is plated, the cold rolled steel sheet (S) is annealed in a reducing atmosphere containing hydrogen in the (B-1) heating zone 22 and the cracking zone 24, and (B-2) the cooling zone 26 ), a process of cooling the cold-rolled steel sheet (S) and performing continuous annealing; (C) a process of continuously sheeting the cold-rolled steel sheet (S) discharged from the annealing furnace (20); (D) a tension reel (50) ) and winding up the cold rolled steel sheet (S) to form a product coil (P) in this order. Then, in step (C), (C-1) the cold-rolled steel sheet (S) is immersed in the hot-dip galvanizing bath (31) located downstream in the plate-feeding direction of the annealing furnace (20), and the cold-rolled steel sheet (S) is coated with molten zinc. A step of plating, followed by (C-2) passing the cold-rolled steel sheet (S) through an alloying furnace (33) located downstream in the passing direction of the hot-dip galvanizing bath (31), and heat-alloying the hot-dip galvanizing plating. Includes the process of This embodiment is a method of manufacturing a product coil of alloyed hot-dip galvanized steel sheet (GA) in which the zinc plating layer is alloyed by CGL 200.

Referring to FIG. 3, a continuous hot dip galvanizing device (CGL) 300 according to the third embodiment of the present invention has the same configuration as CGL 200 except that it does not have an alloying furnace 33. In this embodiment, a product coil of hot-dip galvanized steel sheet (GI) whose zinc plating layer is not alloyed is manufactured by CGL 300.

That is, the method for manufacturing a steel sheet according to the third embodiment in which the process (C-1) is performed and the process (C-2) is not performed is, for example, CGL (300) without the alloying furnace 33. This is realized by, and can also be realized by a method of only passing the steel sheet S through the alloying furnace 33 of the CGL 200 and not performing heat alloying. This embodiment is a method of manufacturing a product coil of hot-dip galvanized steel sheet (GI) whose zinc plating layer is not alloyed by CGL (200) or CGL (300).

Each configuration of CAL according to the first embodiment and CGL according to the second and third embodiments will be described in detail. Additionally, each step in the steel sheet manufacturing method according to the first, second, and third embodiments will be described in detail.

[Pay-off reel and equipment from pay-off reel to annealing furnace]

[Process (A)]

With reference to FIGS. 1 to 3, the pay-off reel 10 dispenses the cold rolled steel sheet S from the cold rolled coil C. That is, in process (A), the cold rolled steel sheet S is discharged from the cold rolled coil C by the pay-off reel 10. The delivered cold-rolled steel sheet S passes through the welder 11, the cleaning equipment 12, and the entrance looper 13, and is supplied to the annealing furnace 20. However, the upstream equipment between the pay-off reel 10 and the annealing furnace 20 is not limited to these welders 11, cleaning equipment 12, and entrance loopers 13, and may be any known or arbitrary equipment. It may be a device.

[annealing furnace]

[Process (B)]

With reference to FIGS. 1 to 3, the annealing furnace 20 carries out continuous annealing by sheeting the cold rolled steel sheet S inside. In the annealing furnace 20, a heating zone 22, a cracking zone 24, and a cooling zone 26 are located from the upstream side in the sheet-through direction, and a reducing atmosphere containing hydrogen is present in the heating zone 22 and the cracking zone 24. The cold rolled steel sheet S is annealed, and the cold rolled steel sheet S is cooled in the cooling zone 26. That is, in step (B), the cold-rolled steel sheet S is passed through the annealing furnace 20 where the heating zone 22, the cracking zone 24, and the cooling zone 26 are located from the upstream side in the passing direction, and continuous annealing is performed. carry out. The cooling zone 26 may be comprised of a plurality of cooling zones. Additionally, there may be a preheating zone on the upstream side of the heating zone 22 in the sheet-through direction. In addition, the annealing furnace 20 of CAL 100 shown in FIG. 1 preferably has an overaging treatment zone 28 downstream of the cooling zone 26, but it is not essential. In Figures 1 to 3, each unit is shown as a vertical furnace, but it is not limited to this and may be a horizontal furnace. In the case of a vertical furnace, adjacent units communicate through a throat (throttle portion) that connects the upper or lower parts of each unit.

(heating stand)

In the heating table 22, the cold-rolled steel sheet S can be heated directly using a burner, or the cold-rolled steel sheet S can be indirectly heated using a radiant tube RT or an electric heater. In addition, heating by induction heating, roll heating, electric resistance heating, direct current heating, salt bath heating, electron beam heating, etc. is also possible. The average temperature inside the heating table 22 is preferably 500 to 800°C. At the same time as the gas from the cracking zone 24 flows into the heating zone 22, a reducing gas is separately supplied. As a reducing gas, a H ₂ -N ₂ mixed gas is usually used, for example, a gas having a composition of H ₂ : 1 to 35% by volume, with the balance consisting of one or both of N ₂ and Ar and inevitable impurities (dew point: - approximately 60°C).

(crack zone)

In the cracking zone 24, the cold rolled steel sheet S can be indirectly heated using the radiant tube RT. The average temperature inside the crack zone 24 is preferably 600 to 950°C. A reducing gas is supplied to the crack zone 24. As a reducing gas, a mixed gas of H ₂ - _{N 2} is usually used, for example, a gas having a composition of H ₂ : 1 to 35% by volume, the balance being one or both of N ₂ and Ar, and inevitable impurities (dew point: -60) degrees Celsius).

(cooling stand)

In the cooling zone 26, the cold rolled steel sheet S is cooled by any one of gas, a mixture of gas and water, and water. At the stage of leaving the annealing furnace 20, the cold rolled steel sheet S is cooled to about 100 to 400°C in CAL and to about 470 to 530°C in CGL. As shown in FIGS. 8(A) and 8(B), a plurality of cooling nozzles 26A are installed in the cooling zone 26 along the steel sheet conveyance path. The cooling nozzle 26A is a circular pipe longer than the width of the steel sheet, as described in, for example, Japanese Patent Application Publication No. 2010-185101, and is installed so that the extension direction of the circular pipe is parallel to the width direction of the steel plate. In the circular pipe, a plurality of through holes are formed at predetermined intervals along the extension direction of the circular pipe at a portion facing the steel plate, and water in the circular pipe is sprayed from the through holes toward the steel plate. The cooling nozzles are installed in pairs so as to face the front and back of the steel sheet, and a plurality of pairs (for example, 5 to 10 pairs) of cooling nozzles are arranged at predetermined intervals along the steel sheet conveyance path, creating one cooling zone. Compose. And, it is preferable to arrange about 3 to 6 cooling zones along the steel sheet conveyance path.

(Experience processing unit)

Referring to FIG. 1, in the CAL 100, in the overaging treatment zone 28, the cold rolled steel sheet S leaving the cooling zone 26 is subjected to at least one of isothermal maintenance, reheating, furnace cooling, and air cooling. Provided, the cold rolled steel sheet (S) is cooled to about 100 to 400°C at the stage of exiting the annealing furnace 20.

[Downstream facilities]

[Process (C)]

1 to 3, in step (C), the cold rolled steel sheet S discharged from the annealing furnace 20 is continuously passed through the downstream equipment 30. Referring to FIG. 1 , CAL 100 has an exit looper 35 and a temper rolling mill 36 as downstream equipment 30 . Referring to FIG. 2, CGL 200 is a downstream facility 30, including a hot-dip galvanizing bath 31, a gas wiping device 32, an alloying furnace 33, a cooling device 34, and an exit looper ( 35), and a temper rolling mill 36. Referring to FIG. 3, CGL 300 includes downstream equipment 30, including a hot-dip galvanizing bath 31, a gas wiping device 32, a cooling device 34, an exit looper 35, and a temper rolling mill. (36). However, the downstream equipment 30 is not limited to these, and may be any known or arbitrary device. For example, the downstream equipment 30 includes a tension leveler, chemical treatment equipment, surface conditioning equipment, oiling equipment, and inspection equipment.

(Hot dip galvanizing bath)

(Process (C-1))

Referring to FIGS. 2 and 3, the hot-dip galvanizing bath 31 is located downstream of the annealing furnace 20 in the sheet-feeding direction, immerses the cold-rolled steel sheet S, and performs hot-dip galvanizing on the cold-rolled steel sheet S. . That is, in step (C-1), the cold-rolled steel sheet S is immersed in the hot-dip galvanizing bath 31 located downstream in the sheet-feeding direction of the annealing furnace 20, and hot-dip galvanizing is performed on the cold-rolled steel sheet S. do. The snout 29 connected to the most downstream zone of the annealing furnace (cooling zone 26 in FIGS. 2 and 3) has a rectangular cross-section perpendicular to the plate direction, which defines the space through which the cold-rolled steel sheet S passes. It is a member, and its tip is immersed in the hot-dip galvanizing bath 31, thereby connecting the annealing furnace 20 and the hot-dip galvanizing bath 31. Hot dip galvanizing may be performed according to the standard method.

A pair of gas wiping devices 32 disposed across the cold-rolled steel sheet S pulled up from the hot-dip galvanizing bath 31 blows gas onto the cold-rolled steel sheet S, thereby wiping the cold-rolled steel sheet S. The amount of molten zinc attached to both sides can be adjusted.

(alloying furnace)

(Process (C-2))

Referring to FIG. 2, the alloying furnace 33 is located downstream in the pass-through direction of the hot-dip galvanizing bath 31 and the gas wiping device 32, passes the cold-rolled steel sheet S, and heat-alloys the hot-dip galvanizing. do. That is, in step (C-2), the cold-rolled steel sheet (S) is passed through the alloying furnace 33 located downstream in the pass-through direction of the hot-dip galvanizing bath 31 and the gas wiping device 32, and hot-dip galvanized. is heated and alloyed. The alloying treatment may be carried out according to the standard method. The heating means in the alloying furnace 33 is not particularly limited, and examples include heating with high-temperature gas and induction heating. However, the alloying furnace 33 is an arbitrary facility in CGL, and the alloying process is an arbitrary step in the method of manufacturing a steel sheet using CGL.

(cooling device)

2 and 3, the cooling device 34 is located downstream of the gas wiping device 32 and the alloying furnace 33 in the sheet-through direction. The cold rolled steel sheet S can be cooled by passing the cold rolled steel sheet S through the cooling device 34. The cooling device 34 cools the cold rolled steel sheet S by water cooling, air cooling, gas cooling, mist cooling, etc.

[Tension Reel]

[Process (D)]

1 to 3, the cold rolled steel sheet S that has passed through the downstream equipment 30 is finally wound by the tension reel 50 as a winding device to become a product coil P.

[Vibration addition device and vibration addition process]

CAL 100 of the first embodiment, CGL 200 of the second embodiment, and CGL 300 of the third embodiment are cold-rolled steel sheets being sold from the cooling table 26 to the tension reel 50. It is important to have a vibration adding device 60 or 70 that adds vibration to (S). That is, in the steel sheet manufacturing method according to the first, second, and third embodiments, after step (B-2) and before step (D), vibration is applied to the cold rolled steel sheet (S) in continuous distribution. It is important to include a vibration addition process that adds. In addition, the vibration added by the vibration adding device 60 or 70 to the cold rolled steel sheet S is such that the frequency of vibration of the cold rolled steel sheet S is 100 Hz or more and 100000 Hz or less, and the maximum frequency of the cold rolled steel sheet S is 100 Hz or more and 100000 Hz or less. It is important that the amplitude is 10 nm or more and 500 μm or less. As a result, hydrogen contained in the cold-rolled steel sheet (S) can be sufficiently and efficiently reduced by annealing, and a steel sheet with excellent hydrogen embrittlement resistance can be manufactured. Additionally, since the addition of vibration is included in the steel sheet manufacturing process (in-line) by CAL (100), CGL (200), or CGL (300), production efficiency is not impaired. Additionally, since hydrogen is desorbed not by heating but by vibration, there is no risk of changing the mechanical properties of the steel sheet.

(Vibration attachment (60))

Each embodiment of the present invention can be realized by installing a vibration adding device 60 as shown in FIG. 4 in CAL 100, CGL 200, or CGL 300, and the vibration adding process includes the vibration adding process. Vibration is added to the cold rolled steel sheet (S) in distribution using the device (60). Referring to FIG. 4 , the vibration adding device 60 includes a controller 61, an amplifier 62, an electromagnet 63, a vibration detector 64, and a power source 65. 6(A) and 6(B), the vibration adding device 60 has an electromagnet 63 including a magnet 63A and a coil 63B that winds the magnet 63A, and the electromagnet (63) has magnetic pole surfaces (63A1) facing away from the surface of the cold rolled steel sheet (S). The vibration adding device 60 is configured to cause the cold rolled steel sheet S to vibrate due to the external force (attractive force) applied to the cold rolled steel sheet S by the electromagnet 63.

The shape and installation mode of the electromagnet 63 are not limited as long as it has a magnetic pole surface 63A1 facing away from the surface of the cold rolled steel sheet S. Thereby, as shown in FIGS. 6(A) and 6(B), the direction of the magnetic force lines becomes perpendicular to the cold rolled steel sheet S, and an attractive force can be applied to the cold rolled steel sheet S. Examples of the shape and installation mode of the electromagnet include FIGS. 5(A) and 5(B).

In FIG. 5 (A), the rectangular electromagnet 63 extends along the steel sheet width direction at a predetermined distance from the surface of the cold rolled steel sheet S, and thus the width of the surface of the cold rolled steel sheet S External force (attractive force) can be applied uniformly in each direction, and uniform vibration can be achieved in the width direction. And by arranging a plurality of such electromagnets 63 along the sheet-feeding direction, sufficient time for adding vibration to the cold-rolled steel sheet S can be secured. As shown in Fig. 5 (A), the electromagnet 63 has a magnet 63A and a coil 63B wound around it, and the axial direction of the coil 63B is the thickness of the cold rolled steel sheet S. Match the direction. In this case, depending on the direction of the current flowing in the coil 63B, the magnetic pole surface 63A1 facing the cold rolled steel sheet S becomes the N pole, as shown in FIG. 6(A), or as shown in FIG. 6(B). Likewise, the magnetic pole surface 63A1 opposing the cold rolled steel sheet S becomes the S pole.

In Figure 5 (B), a plurality of cylindrical electromagnets 63 are arranged at predetermined intervals along the width direction of the steel sheet so that the magnetic pole surfaces of the bottom thereof face apart from the surface of the cold rolled steel sheet S. , As a result, external force (attractive force) can be uniformly applied to the surface of the cold rolled steel sheet S in the width direction, and uniform vibration in the width direction can be realized. And by arranging a plurality of rows of such cylindrical electromagnets 63 along the sheet-feeding direction, sufficient time for adding vibration to the cold-rolled steel sheet S can be secured. As shown in Fig. 5 (B), each electromagnet 63 has a cylindrical magnet and a coil wound around it, and the axial direction of the coil coincides with the sheet thickness direction of the cold rolled steel sheet S. . In this case, depending on the direction of the current flowing in the coil, the magnetic pole surface 63A1 facing the cold rolled steel sheet S becomes the N pole, as shown in FIG. 6 (A), or the cold rolled steel sheet S becomes the N pole, as shown in FIG. 6 (B). The magnetic pole surface 63A1 opposing the steel plate S becomes the S pole.

In the case of Fig. 6 (A) and Fig. 6 (B), an external force (attractive force) acts on the cold rolled steel sheet S by passing a current through the electromagnet 63. The current flowing through the electromagnet 63 is a direct current pulse current or an alternating current continuous current. When a direct pulse current is passed through the electromagnet 63, an attractive force intermittently acts on the cold rolled steel sheet S, causing the cold rolled steel sheet S to vibrate. When a continuous alternating current is passed through an electromagnet, each time the direction of the current changes, the magnetic pole surface 63A1 facing the cold rolled steel sheet S is switched between the N pole and the S pole, but the cold rolled steel sheet S always has External force (attractive force) acts. In the case of alternating current, the magnitude of the external force (attractive force) acting on the cold-rolled steel sheet S also changes as the current value changes over time, so the cold-rolled steel sheet S vibrates.

In addition, it is sufficient to install the electromagnet 63 so as to face one surface of the cold rolled steel sheet S, but may also be installed so as to face both the front and back sides. However, in that case, it is preferable to shift the height positions so that the electromagnet on one side is not at the same height as the electromagnet on the other side.

The vibration detector 64 shown in FIG. 4 is a laser displacement meter or a laser Doppler vibrometer disposed at a predetermined distance from the surface of the cold rolled steel sheet S, and can measure the frequency and amplitude of vibration of the cold rolled steel sheet S. . By arranging the vibration detector 64 at the same height position as the electromagnet 63 of the cold rolled steel sheet S, the maximum amplitude of vibration of the cold rolled steel sheet S can be measured with the vibration detector 64. The frequency and maximum amplitude detected by the vibration detector 64 are output to the controller 61. The controller 61 receives the values of the frequency and maximum amplitude output from the vibration detector 64, compares them with the set value, performs PID calculation, etc. on the deviation, and sets the cold rolled steel sheet S to a predetermined frequency and maximum amplitude. To oscillate at an amplitude, the frequency (frequency of a direct current pulse current or the frequency of an alternating current continuous current) and current value of the electromagnet 63 are determined, and the amplification factor of the amplifier 62 is taken into consideration and given to the amplifier 62. Determine the current value and give the command value to the power supply (65). The power source 65 is a power source for passing a current to the coil of the electromagnet 63, and receives a command value input from the controller 61, and provides a current of a predetermined frequency and current value to the amplifier 62. The amplifier 62 amplifies the current value supplied from the power source 65 at a predetermined amplification factor and provides a command value to the electromagnet 63. As a result, a current of a predetermined frequency and current value flows through the electromagnet 63, making it possible to vibrate the cold rolled steel sheet S at a predetermined frequency and maximum amplitude.

(Vibration attachment (70))

Each embodiment of the present invention can be realized by installing the vibration adding device 70 as shown in FIG. 7A in the CAL 100, CGL 200, or CGL 300, and the vibration adding process includes the vibration adding process. Vibration is added to the cold rolled steel sheet S in distribution using the device 70. Referring to FIG. 7A, the vibration adding device 70 includes a controller 71, a vibrator 72, and a vibration detector 73. The vibration adding device 70 has a vibrator 72 in contact with the cold rolled steel sheet S, and is configured to cause the cold rolled steel sheet S to vibrate by the vibrator 72.

The vibrator 72 is not particularly limited as long as it is a general piezoelectric element, and its shape and installation mode are not limited. For example, as shown in FIG. 7B, the flat vibrator 72 with the sheet width direction toward the length is cold rolled. By bringing the steel sheet (S) into surface contact, the cold rolled steel sheet (S) can be vibrated.

In addition, it is sufficient to install the vibrator 72 so as to contact one surface of the cold rolled steel sheet S, but may be installed so as to contact both the front and back surfaces. However, in that case, it is desirable to shift the height positions so that the vibrator on one side is not at the same height as the vibrator on the other side.

The vibration detector 73 shown in FIG. 7A is a laser displacement meter or a laser Doppler vibrometer disposed at a predetermined distance from the surface of the cold rolled steel sheet S, and can measure the frequency and amplitude of vibration of the cold rolled steel sheet S. . By arranging the vibration detector 73 at the same height position as the vibrator 72 of the cold rolled steel sheet S, the maximum amplitude of vibration of the cold rolled steel sheet S can be measured with the vibration detector 73. The frequency and maximum amplitude detected by the vibration detector 73 are output to the controller 71. The controller 71 receives the values of the frequency and maximum amplitude output from the vibration detector 73, compares them with the set value, performs PID calculation, etc. on the deviation, and sets the cold rolled steel sheet S to a predetermined frequency and maximum amplitude. To cause vibration at an amplitude, the frequency and current value of the direct current pulse current flowing through the vibrator 72 are determined, and a power supply (not shown) is controlled to provide the vibrator 72 with a direct current pulse current of a predetermined frequency and current value. Thereby, the vibrator 72 vibrates at a predetermined frequency and amplitude, and as a result, the cold rolled steel sheet S can be vibrated at a predetermined frequency and maximum amplitude.

In the first, second, and third embodiments, the position of the vibration adding device 60 or 70 is such that vibration is applied to the cold rolled steel sheet S being passed from the cooling table 26 to the tension reel 50. It is not limited as long as it can be added.

Referring to Figure 1, in the first embodiment of manufacturing a product coil of cold rolled annealed steel sheet (CR) with CAL 100, the preferred location of the vibration adding device 60 or 70, i.e. the preferred timing of implementation of the vibration adding process. Explain. As an example, a vibration adding device (60 or 70) can be installed on the cooling table (26). In this case, the vibration addition process can be performed in process (B-2). Specifically, the electromagnet 63 shown in Fig. 4 or the electromagnet 63 shown in Fig. 4 or between the cooling zones arranged in plurality along the steel sheet conveyance path or between the cooling nozzles adjacent to each other along the steel sheet conveyance path in each cooling zone is used. The vibrator 72 shown in can be installed. 8 (A) and (B), examples of the positional relationship between the cooling nozzle 26A and the vibration adding device 60 or 70 when the vibration adding device 60 or 70 is installed in the cooling table 26. represents. In addition, the entire vibration adding device 60 or 70 does not need to be located inside the cooling table 26, and at least the electromagnet 63 or the vibrator 72 may be located inside the cooling table 26.

As another example, the vibration adding device 60 or 70 can be installed in a position where vibration can be added to the cold rolled steel sheet S being passed through the downstream facility 30. In this case, the vibration addition process can be performed in process (C). Specifically, (i) between the overaging treatment table 28 and the exit looper 35, (ii) within the exit looper 35, (iii) between the exit looper 35 and the temper rolling mill 36, (iv) A vibration adding device (60 or 70) can be installed at least between the temper rolling mill (36) and the tension reel (50).

The vibration adding device 60 or 70 may be installed at both the cooling table 26 and the downstream facility 30 at a position where vibration can be applied to the cold rolled steel sheet S being passed through. That is, the vibration addition process may be installed in both process (B-2) and process (C). Additionally, the vibration adding device 60 or 70 may be installed in the overaging treatment zone 28, and the vibration adding process may be performed during the overaging treatment.

Next, referring to FIG. 2, in the second embodiment of manufacturing a product of alloyed hot-dip galvanized steel sheet (GA) with CGL 200, the preferred location of the vibration adding device 60 or 70, i.e., the vibration addition process Describes the preferred implementation timing. As an example, the vibration adding device 60 or 70 can be installed at a first position where vibration can be applied to the cold rolled steel sheet S being sold upstream of the hot dip galvanizing bath 31. In this case, the vibration addition process can be performed before process (C-1). Specifically, the vibration adding device 60 or 70 can be installed on the cooling table 26. More specifically, the electromagnet 63 shown in FIG. 4 or the electromagnet 63 shown in FIG. 7A is placed between a plurality of cooling zones arranged along the steel sheet conveyance path or between cooling nozzles adjacent to each other along the steel sheet conveyance path in each cooling zone. The vibrator 72 shown in B can be installed. Also in this embodiment, the examples shown in FIGS. 8(A) and 8(B) are suitable. In addition, the entire vibration adding device 60 or 70 does not need to be located inside the cooling table 26, and at least the electromagnet 63 or the vibrator 72 may be located inside the cooling table 26. Additionally, at least the electromagnet 63 or vibrator 72 of the vibration adding device 60 or 70 may be installed in the snout 29.

As another example, the vibration adding device 60 or 70 can be installed at a second position where vibration can be applied to the cold rolled steel sheet S being passed downstream from the hot dip galvanizing bath 31. In this case, the vibration addition process can be performed later than process (C-1). Specifically, (i) between the hot dip galvanizing bath 31 and the gas wiping device 32, (ii) between the gas wiping device 32 and the alloying furnace 33, (iii) the alloying furnace ( 33) inside, (iv) air cooling zone between alloying furnace 33 and cooling device 34, (v) between cooling device 34 and exit looper 35, (vi) within exit looper 35, A vibration adding device (60 or 70) can be installed at least one of (vii) between the output looper 35 and the temper rolling mill 36, and (viii) between the temper rolling mill 36 and the tension reel 50. In particular, it is preferable to install the vibration adding device 60 or 70 in the air cooling zone (iv).

From the viewpoint of more sufficiently desorbing hydrogen from the steel sheet, it is preferable to install the vibration adding device 60 or 70 at the first position rather than the second position. That is, it is preferable that the vibration addition process is performed before step (C-1) rather than after step (C-1). However, the vibration adding device 60 or 70 may be installed at both the first position and the second position. That is, the vibration addition process may be provided both before and after the process (C-1).

Next, referring to FIG. 3, in the third embodiment of manufacturing a hot-dip galvanized steel sheet (GI) product with the CGL 300, the preferred position of the vibration adding device 60 or 70, that is, the vibration adding process, is shown. Preferred implementation timing is explained. As an example, the vibration adding device 60 or 70 can be installed at a first position where vibration can be applied to the cold rolled steel sheet S being sold upstream of the hot dip galvanizing bath 31. In this case, the vibration addition process can be performed before process (C-1). Specifically, the vibration adding device 60 or 70 can be installed on the cooling table 26. More specifically, the electromagnet 63 shown in FIG. 4 or the electromagnet 63 shown in FIG. 7A is installed between a plurality of cooling zones arranged along the steel sheet conveyance path or between cooling nozzles adjacent to each other along the steel sheet conveyance path in each cooling zone. The vibrator 72 shown in B can be installed. Also in this embodiment, the examples shown in FIGS. 8(A) and 8(B) are suitable. In addition, the entire vibration adding device 60 or 70 does not need to be located inside the cooling table 26, and at least the electromagnet 63 or the vibrator 72 may be located inside the cooling table 26. Additionally, at least the electromagnet 63 or vibrator 72 of the vibration adding device 60 or 70 may be installed in the snout 29.

As another example, the vibration adding device 60 or 70 can be installed at a second position where vibration can be applied to the cold-rolled steel sheet S being passed downstream from the hot-dip galvanizing bath 31. In this case, the vibration addition process can be performed later than process (C-1). Specifically, (i) between the hot dip galvanizing bath 31 and the gas wiping device 32, (ii) an air cooling zone between the gas wiping device 32 and the cooling device 34, (iii) Between the cooling device 34 and the exit looper 35, (iv) within the exit looper 35, (v) between the exit looper 35 and the temper rolling mill 36, (vi) with the temper rolling mill 36 A vibration adding device (60 or 70) can be installed between the tension reels (50). In particular, it is preferable to install the vibration adding device 60 or 70 in the air cooling zone of (ii).

From the viewpoint of more sufficiently desorbing hydrogen from the steel sheet, it is preferable to install the vibration adding device 60 or 70 at the first position rather than the second position. That is, it is preferable that the vibration addition process is performed before step (C-1) rather than after step (C-1). However, the vibration adding device 60 or 70 may be installed at both the first position and the second position. That is, the vibration addition process may be provided both before and after the process (C-1).

(frequency of vibration)

From the viewpoint of promoting hydrogen diffusion, it is important that the frequency of vibration of the cold rolled steel sheet (S) is 100 Hz or more. When the frequency is less than 100 Hz, the effect of desorbing hydrogen contained in the cold rolled steel sheet (S) is not obtained. From this point of view, the frequency is set to 100 Hz or higher, preferably 500 Hz or higher, and more preferably 1000 Hz or higher. In addition, the cold-rolled steel sheet S vibrates on its own during the sheet-feeding process or, for example, receives gas from the gas wiping device 32 and vibrates. However, in these vibrations, the frequency of vibration of the cold rolled steel sheet S is at most about 20 Hz, and in this case, the effect of desorbing hydrogen contained in the cold rolled steel sheet S is not obtained. On the other hand, if the frequency is excessive, sufficient time cannot be secured to expand the lattice spacing within the steel sheet, and the effect of desorbing hydrogen cannot be obtained. From this point of view, it is important that the frequency is 100,000 Hz or less, preferably 80,000 Hz or less, and more preferably 50,000 Hz or less. The frequency of vibration of the cold rolled steel sheet S can be measured by the vibration detector 64 shown in FIG. 4 or the vibration detector 73 shown in FIG. 7A. In addition, the frequency of vibration of the cold rolled steel sheet S can be adjusted by controlling the frequency of the direct current pulse current or the frequency of the alternating current continuous current in the case of the vibration adding device 60 shown in Fig. 4, and Figs. 7A, B In the case of the vibration adding device 70 shown in , adjustment can be made by controlling the vibration frequency of the vibrator 72.

(maximum amplitude of vibration)

When the maximum amplitude of the cold-rolled steel sheet (S) is less than 10 nm, the lattice spacing on the surface of the steel sheet is not sufficiently expanded and the promotion of hydrogen diffusion is insufficient, so the effect of desorbing hydrogen contained in the cold-rolled steel sheet (S) is not obtained. No. Therefore, it is important that the maximum amplitude of the cold rolled steel sheet (S) is 10 nm or more, preferably 100 nm or more, and more preferably 500 nm or more. Additionally, when the maximum amplitude of the cold-rolled steel sheet (S) is greater than 500 μm, the strain on the surface of the steel sheet increases, causes plastic deformation, and as a result traps hydrogen, thereby desorbing the hydrogen contained in the cold-rolled steel sheet (S). The desired effect is not obtained. From this viewpoint, it is important that the maximum amplitude of the cold rolled steel sheet (S) is 500 μm or less, preferably 400 μm or less, and more preferably 300 μm or less. In addition, the cold-rolled steel sheet S vibrates on its own during the sheet-feeding process or, for example, receives gas from the gas wiping device 32 and vibrates. However, in these vibrations, the maximum amplitude of the cold rolled steel sheet S exceeds at least 0.5 mm, so the effect of desorbing hydrogen contained in the cold rolled steel sheet S is not obtained. The maximum amplitude of the cold rolled steel sheet S can be measured by the vibration detector 64 shown in FIG. 4 or the vibration detector 73 shown in FIG. 7A. In addition, the maximum amplitude of the cold rolled steel sheet S can be adjusted by controlling the amount of current flowing through the electromagnet 63 in the case of the vibration adding device 60 shown in Fig. 4, and the vibration applying device 70 shown in Figs. 7A and B ) In the case of , it can be adjusted by controlling the amplitude of vibration of the vibrator 72.

(Vibration additional time)

From the viewpoint of more sufficiently reducing hydrogen from the cold-rolled steel sheet (S), in the vibration addition process, the time for adding vibration to the cold-rolled steel sheet (S) is preferably 1 second or more, and more preferably 5 seconds or more. And, it is more preferable to set it to 10 seconds or more. On the other hand, from the viewpoint of not impairing productivity, the time for adding vibration to the cold rolled steel sheet S is preferably 3600 seconds or less, more preferably 1800 seconds or less, and even more preferably 900 seconds or less. . In this specification, “the time for adding vibration to the cold-rolled steel sheet (S)” means the time for which vibration is added to each position on the surface of the cold-rolled steel sheet (S), and each position is provided by a plurality of vibration adding devices (60). Or when vibration from 70) is given, it means the accumulated time. 6(A) and 6(B), when the vibration adding device 60 is used, the portion of the surface of the cold rolled steel sheet S facing the electromagnet 63 can be considered to be vibrating. Therefore, the time that each part of the cold rolled steel sheet S is facing the electromagnet 63 can be integrated as the vibration added time. When using the vibration adding device 70 shown in FIGS. 7A and 7B, the integration of the time during which each part of the cold rolled steel sheet S is in contact with the vibrator 72 can be taken as the vibration adding time. The vibration addition time is determined by the rolling speed of the cold rolled steel sheet S and the position of the vibration adding device 60 or 70 (for example, the number along the rolling direction of the electromagnet 63 shown in FIG. 4 or shown in FIGS. 7A and B) It can be adjusted by the number along the plate direction of the vibrator 72.

[Cold rolled steel plate]

In this embodiment, the cold rolled steel sheet (S) supplied to CAL (100), CGL (200), and CGL (300) is not particularly limited. The cold-rolled steel sheet (S) preferably has a thickness of less than 6 mm, and examples include high-strength steel sheets and stainless steel sheets having a tensile strength of 590 MPa or more.

[Composition of cold-rolled steel sheets: high-strength steel sheets]

The component composition when the cold-rolled steel sheet (S) is a high-strength steel sheet will be described. Hereinafter, “mass %” is simply written as “%”.

C: 0.030 to 0.800%

C has the effect of increasing the strength of the steel sheet. From the viewpoint of obtaining this effect, the amount of C is set to 0.030% or more, and preferably 0.080% or more. However, when the amount of C is excessive, the steel sheet becomes significantly embrittled regardless of the amount of hydrogen in the steel sheet. Therefore, the amount of C is set to 0.800% or less, and preferably 0.500% or less.

Si: 0.01 to 3.00%

Si has the effect of increasing the strength of the steel sheet. From the viewpoint of obtaining this effect, the amount of Si is set to 0.01% or more, and preferably 0.10% or more. However, if the amount of Si is excessive, the steel sheet becomes embrittled and ductility is reduced, red scale occurs, the surface properties deteriorate, or plating quality deteriorates. Therefore, the amount of Si is set to 3.00% or less, preferably 2.50% or less.

Mn: 0.01 to 10.00%

Mn has the effect of increasing the strength of the steel sheet through solid solution strengthening. From the viewpoint of obtaining this effect, the amount of Mn is set to 0.01% or more, and preferably 0.5% or more. However, when the amount of Mn is excessive, unevenness is likely to occur in the steel structure due to segregation of Mn, and hydrogen embrittlement starting from the unevenness may become apparent. Therefore, the amount of Mn is set to 10.00% or less, and preferably 8.00% or less.

P: 0.001 to 0.100%

P is an element that has a solid solution strengthening effect and can be added depending on the desired strength. From the viewpoint of obtaining this effect, the amount of P is set to 0.001% or more, and preferably 0.003% or more. However, when the amount of P is excessive, weldability deteriorates, and when alloying zinc plating, the alloying speed decreases, impairing the quality of the zinc plating. Therefore, the amount of P is set to 0.100% or less, preferably 0.050% or less.

S: 0.0001 to 0.0200%

S segregates at grain boundaries and embrittles the steel during hot processing, and exists as sulfide to reduce local deformability. Therefore, the amount of S is set to 0.0200% or less, preferably 0.0100% or less, and more preferably 0.0050% or less. Meanwhile, due to constraints in production technology, the amount of S is set to 0.0001% or more.

N: 0.0005 to 0.0100%

N is an element that deteriorates the aging resistance of steel. Therefore, the amount of N is set to 0.0100% or less, and preferably 0.0070% or less. A smaller amount of N is more preferable, but due to constraints in production technology, the amount of N is set to 0.0005% or more, and preferably 0.0010% or more.

Al: 0.001 to 2.000%

Al acts as a deoxidizer and is an element effective in improving the cleanliness of steel. From the viewpoint of obtaining this effect, the amount of Al is set to 0.001% or more, and preferably 0.010% or more. However, if the Al amount is excessive, there is a possibility that steel sheet cracks may occur during continuous casting. Therefore, the Al amount is set to 2.000% or less, preferably 1.200% or less.

The remainder other than the above components is Fe and inevitable impurities. However, it may optionally contain at least one element selected from the following.

Ti: 0.200% or less

Ti contributes to increasing the strength of the steel sheet through precipitation strengthening of the steel and fine grain strengthening by suppressing the growth of ferrite crystal grains. Therefore, when adding Ti, the amount of Ti is preferably 0.005% or more, and more preferably 0.010% or more. However, when the amount of Ti is excessive, carbonitride may precipitate in large amounts, and formability may deteriorate. Therefore, when adding Ti, the amount of Ti is set to 0.200% or less, and preferably 0.100% or less.

Nb: 0.200% or less, V: 0.500% or less, W: 0.500% or less

Nb, V, and W are effective in precipitation strengthening of steel. Therefore, when adding Nb, V, and W, the content of each element is preferably 0.005% or more, and more preferably 0.010% or more. However, when each content is excessive, a large amount of carbonitride may precipitate and formability may deteriorate. Therefore, when adding Nb, the amount of Nb is set to 0.200% or less, and preferably 0.100% or less. When adding V and W, the content of each element is set to 0.500% or less, preferably 0.300% or less.

B: 0.0050% or less

B is effective in strengthening grain boundaries and increasing the strength of steel sheets. Therefore, when adding B, it is preferable that the amount of B is 0.0003% or more. However, when the amount of B is excessive, moldability may deteriorate. Therefore, when adding B, the amount of B is set to 0.0050% or less, and preferably 0.0030% or less.

Ni: 1.000% or less

Ni is an element that increases the strength of steel through solid solution strengthening. Therefore, when adding Ni, it is preferable that the amount of Ni is 0.005% or more. However, when the amount of Ni is excessive, the area ratio of hard martensite becomes excessive, microvoids at the grain boundaries of martensite increase during a tensile test, further propagation of cracks progresses, and ductility decreases. There are cases where it happens. Therefore, when adding Ni, the amount of Ni is set to 1.000% or less.

Cr: 1.000% or less, Mo: 1.000% or less

Cr and Mo have the effect of improving the balance between strength and formability. Therefore, when adding Cr and Mo, it is preferable that the content of each element is 0.005% or more. However, when each content is excessive, the area ratio of hard martensite becomes excessive, microvoids at the grain boundaries of martensite increase during tensile testing, further crack propagation progresses, and ductility decreases. There are cases where it deteriorates. Therefore, when adding Cr and Mo, the content of each element is set to 1.000% or less.

Cu: 1.000% or less

Cu is an element effective in strengthening steel. Therefore, when adding Cu, it is preferable that the amount of Cu is 0.005% or more. However, when the amount of Cu is excessive, the area ratio of hard martensite becomes excessive, microvoids at the grain boundaries of the tempered martensite increase during the tensile test, and further crack propagation progresses, resulting in ductility. There are cases where this deteriorates. Therefore, when adding Cu, the amount of Cu is set to 1.000% or less.

Sn: 0.200% or less, Sb: 0.200% or less

Sn and Sb are effective in suppressing decarburization of a region of about several tens of micrometers in the surface layer of the steel sheet caused by nitriding or oxidation on the surface of the steel sheet, and in ensuring strength and material stability. Therefore, when adding Sn and Sb, it is preferable that the content of each element is 0.002% or more. However, when each content is excessive, toughness may decrease. Therefore, when adding Sn and Sb, the content of each element is set to 0.200% or less.

Ta: 0.100% or less

Ta, like Ti and Nb, contributes to increasing strength by forming alloy carbides and alloy carbonitrides. In addition, it is partially dissolved in Nb carbide or Nb carbonitride, producing complex precipitates such as (Nb, Ta) (C, N), thereby significantly suppressing the coarsening of the precipitates and contributing to the strength by precipitation strengthening. I think it has a stabilizing effect. Therefore, when adding Ta, it is preferable that the amount of Ta is 0.001% or more. However, even if Ta is added excessively, the precipitate stabilizing effect may be saturated and alloying costs also increase. Therefore, when adding Ta, the amount of Ta is set to 0.100% or less.

Ca: 0.0050% or less, Mg: 0.0050% or less, Zr: 0.1000% or less, REM (Rare Earth Metal): 0.0050% or less

Ca, Mg, Zr, and REM are effective elements for spheroidizing the shape of sulfide and improving the adverse effects of sulfide on formability. When adding these elements, the content of each element is preferably 0.0005% or more. However, when each content is excessive, inclusions, etc. increase, and surface and internal defects may occur. Therefore, when adding these elements, the content of each element is set to 0.0050% or less.

[Composition of cold rolled steel sheet: stainless steel sheet]

The component composition when the cold rolled steel sheet (S) is a stainless steel sheet will be described. Hereinafter, “mass %” is simply written as “%”.

C: 0.001 to 0.400%

C is an essential element for obtaining high strength in stainless steel. However, during tempering in steel production, it combines with Cr and precipitates as carbide, which deteriorates the corrosion resistance and toughness of the steel. If the amount of C is less than 0.001%, sufficient strength cannot be obtained, and if the amount of C exceeds 0.400%, the deterioration becomes significant. For this reason, the amount of C is set to 0.001 to 0.400%.

Si: 0.01 to 2.00%

Si is an element useful as a deoxidizing agent. From the viewpoint of obtaining this effect, the amount of Si is set to 0.01% or more. However, when the amount of Si is excessive, Si dissolved in steel reduces the workability of the steel. Therefore, Si is set to 2.00% or less.

Mn: 0.01 to 5.00%

Mn has the effect of increasing the strength of steel. From the viewpoint of obtaining this effect, the amount of Mn is set to 0.01% or more. However, when the amount of Mn is excessive, the workability of the steel deteriorates. Therefore, the amount of Mn is set to 5.00% or less.

P: 0.001 to 0.100%

P is an element that promotes grain boundary destruction due to grain boundary segregation. For this reason, the P amount is preferably low, 0.100% or less, preferably 0.030% or less, and more preferably 0.020% or less. Meanwhile, due to constraints in production technology, the amount of P is set to 0.001% or more.

S: 0.0001 to 0.0200%

S exists as sulfide-based inclusions such as MnS and reduces ductility, corrosion resistance, etc. For this reason, the amount of S is preferably low, 0.0200% or less, preferably 0.0100% or less, and more preferably 0.0050% or less. Meanwhile, due to constraints in production technology, the amount of S is set to 0.0001% or more.

Cr: 9.0 to 28.0%

Cr is a basic element that constitutes stainless steel, and is also an important element that exhibits corrosion resistance. When considering corrosion resistance in harsh environments of 180°C or higher, sufficient corrosion resistance cannot be obtained if the Cr amount is less than 9.0%, and if it exceeds 28.0%, the effect is saturated and a problem arises in terms of economic efficiency. For this reason, the amount of Cr is set to 9.0 to 28.0%.

Ni: 0.01 to 40.0%

Ni is an element that improves the corrosion resistance of stainless steel. If the Ni amount is less than 0.01%, the effect is not sufficiently exerted. On the other hand, when the amount of Ni is excessive, not only does the formability deteriorate, but stress corrosion cracking becomes prone to occur. For this reason, the amount of Ni is set to 0.01 to 40.0%.

N: 0.0005 to 0.500%

N is an element harmful to improving the corrosion resistance of stainless steel. Therefore, the amount of N is set to 0.500% or less, and preferably 0.200% or less. A smaller amount of N is more preferable, but due to constraints in production technology, the amount of N is set to 0.0005% or more.

Al: 0.001 to 3.000%

In addition to acting as a deoxidizing agent, Al has the effect of suppressing peeling of oxidized scale. From the viewpoint of obtaining these effects, the Al amount is set to 0.001% or more. However, when the amount of Al is excessive, growth decreases and surface quality deteriorates. Therefore, the Al amount is set to 3.000% or less.

The remainder other than the above components is Fe and inevitable impurities. However, it may optionally contain at least one element selected from the following.

Ti: 0.500% or less

Ti combines with C, N, and S to improve corrosion resistance, intergranular corrosion resistance, and deep drawing properties. However, when the amount of Ti is more than 0.500%, toughness deteriorates due to dissolved Ti. Therefore, when adding Ti, the amount of Ti is set to 0.500% or less.

Nb: 0.500% or less

Nb, like Ti, combines with C, N, and S to improve corrosion resistance, intergranular corrosion resistance, and deep drawing properties. Additionally, in addition to improving processability and improving high-temperature strength, it also suppresses crevice corrosion and promotes re-passivation. However, excessive addition causes hardening and deteriorates formability. Therefore, when adding Nb, the amount of Nb is set to 0.500% or less.

V: 0.500% or less

V suppresses crevice corrosion. However, excessive addition deteriorates formability. Therefore, when adding V, the amount of V is set to 0.500% or less.

W: 2.000% or less

W contributes to improving corrosion resistance and high-temperature strength. However, excessive addition leads to deterioration of toughness and increased cost during steel sheet production. Therefore, when adding W, the amount of W is set to 2.000% or less.

B: 0.0050% or less

B improves the secondary processability of the product by segregating at grain boundaries. However, excessive addition leads to a decrease in processability and corrosion resistance. Therefore, when adding B, the amount of B is set to 0.0050% or less.

Mo: 2.000% or less

Mo is an element that improves corrosion resistance and especially suppresses crevice corrosion. However, excessive addition deteriorates formability. Therefore, when adding Mo, the amount of Mo is set to 2.000% or less.

Cu: 3.000% or less

Cu, like Ni and Mn, is an austenite stabilizing element and is effective in refining crystal grains by phase transformation. Additionally, it suppresses crevice corrosion and promotes re-passivation. However, excessive addition deteriorates toughness and formability. Therefore, when adding Cu, the amount of Cu is set to 3.000% or less.

Sn: 0.500% or less

Sn contributes to improving corrosion resistance and high-temperature strength. However, excessive addition may cause slab cracking during steel sheet manufacturing. Therefore, when adding Sn, the amount of Sn is set to 0.500% or less.

Sb: 0.200% or less

Sb has the effect of increasing high-temperature strength by segregating at grain boundaries. However, excessive addition may cause cracks during welding due to Sb segregation. Therefore, when adding Sb, the amount of Sb is set to 0.200% or less.

Ta: 0.100% or less

Ta combines with C and N to contribute to improving toughness. However, with excessive addition, the effect is saturated and leads to an increase in manufacturing cost. Therefore, when adding Ta, the amount of Ta was set to 0.100% or less.

Ca: 0.0050% or less, Mg: 0.0050% or less, Zr: 0.1000% or less, REM (Rare Earth Metal): 0.0050% or less

Ca, Mg, Zr, and REM are effective elements for spheroidizing the shape of sulfide and improving the adverse effects of sulfide on formability. When adding these elements, the content of each element is preferably 0.0005% or more. However, when each content is excessive, inclusions, etc. increase, and surface and internal defects may occur. Therefore, when adding these elements, the content of each element is set to 0.0050% or less.

[Diffusible hydrogen amount]

In this embodiment, in order to ensure good bendability, the amount of diffusible hydrogen in the product coil is preferably 0.50 mass ppm or less, more preferably 0.30 mass ppm or less, and 0.20 mass ppm or less. It is more desirable. In addition, the lower limit of the amount of diffusible hydrogen in the product coil is not specifically specified, but due to constraints in production technology, the amount of diffusible hydrogen in the product coil can be 0.01 ppm by mass or more.

Here, the method for measuring the amount of diffusible hydrogen in the product coil is as follows. From the product coil, a test piece with a length of 30 mm and a width of 5 mm is taken. For product coils of hot-dip galvanized steel or alloyed hot-dip galvanized steel, the hot-dip galvanized layer or alloyed hot-dip galvanized layer of the test piece is removed by grinding or alkali. Thereafter, the amount of hydrogen released from the test piece is measured by thermal desorption spectrometry (TDS). Specifically, the test piece was continuously heated from room temperature to 300°C at a temperature increase rate of 200°C/h, then cooled to room temperature, and the accumulated amount of hydrogen released from the test piece from room temperature to 210°C was measured to determine the diffusivity of the product coil. Do it in small quantities.

Example

Steel having the elements shown in Table 1 and a composition with the remainder being Fe and inevitable impurities was melted in a converter and made into a slab by continuous casting. The obtained slab was hot rolled and cold rolled to obtain a cold rolled coil. As shown in Table 2, at some levels, product coils of cold rolled annealed steel sheet (CR) are manufactured by CAL shown in FIG. 1, and at other levels, heat alloying is not performed by CGL shown in FIG. 2, Product coils of hot-dip galvanized steel sheet (GI) were manufactured and, at the remaining level, product coils of alloyed hot-dip galvanized steel sheet (GA) by CGL as shown in Figure 2.

At each level, vibration was added to the cold rolled steel sheet in distribution using an electronic vibration adding device as shown in FIGS. 4 to 6 under the conditions of maximum amplitude, frequency, and vibration addition time shown in Table 2. “Vibration addition point” in Table 2 indicates the area where the vibration addition process in CAL or CGL was performed, that is, the location where the vibration addition device was installed.

“(B-2)” means that in CAL and CGL, a vibration adding device was installed on the cooling table, and the vibration adding process was performed on the cooling table in step (B-2).

“(C)” means that in CAL, a vibration adding device is installed at a location where vibration can be added to the cold rolled steel sheet being sold through downstream facilities, and is located at a location downstream from the cooling zone and upstream from the tension reel, specifically, (i) between the overaging treatment table 28 and the exit looper 35, (ii) within the exit looper 35, (iii) between the exit looper 35 and the temper rolling mill 36, (iv) temper This means that a vibration adding device is installed at at least one point between the rolling mill 36 and the tension reel 50. That is, “(C)” means that in CAL, the vibration addition step was performed in step (C), specifically, at least one point of (i) to (iv) above.

“Before (C-1)”, in the CGL, a vibration adding device is installed at a location downstream from the cooling zone and upstream from the hot-dip galvanizing bath, specifically, at the snout 29, and the vibration addition device is installed before step (B-2). This means that the vibration addition process was performed after and before process (C-1).

“After (C-1)” refers to a position downstream of the hot-dip galvanizing bath and upstream of the tension reel in the CGL, specifically (i) between the hot-dip galvanizing bath 31 and the gas wiping device 32. (ii) between the gas wiping device (32) and the alloying furnace (33), (iii) within the alloying furnace (33), (iv) between the alloying furnace (33) and the cooling device (34). , (v) between the cooling device 34 and the exit looper 35, (vi) within the exit looper 35, (vii) between the exit looper 35 and the temper rolling mill 36, (viii) the temper rolling mill. A vibration adding device is installed at at least one point between (36) and the tension reel (50), and after step (C-1), specifically, vibration is applied at at least one point in (i) to (viii) above. This means that additional processes were performed.

Samples of steel sheets were collected from the product coils obtained at each level, and evaluated for tensile properties and hydrogen embrittlement resistance as follows, and the results are shown in Table 2.

The tensile test was conducted in accordance with JIS Z 2241 (2011) using JIS No. 5 test pieces sampled so that the tensile direction was perpendicular to the rolling direction of the steel plate, and TS (tensile strength) and EL (total elongation) were measured. ) was measured.

Hydrogen embrittlement resistance was evaluated from the above tensile test as follows. When the EL of the steel sheet after vibration measured above divided by EL' when the amount of hydrogen in the steel of the same steel sheet is 0.00 ppm by mass was 0.70 or more, the hydrogen embrittlement resistance was judged to be good. Additionally, EL' is measured by reducing the hydrogen in the steel inside the same steel sheet by leaving it in the air for a long time, and then performing a tensile test after confirming that the amount of hydrogen in the steel has reached 0.00 ppm by mass by TDS. did.

The amount of diffusible hydrogen in the product coil obtained at each level was measured by the method already described, and the results are shown in Table 2.

In the present invention example, since the vibration addition process was performed under the conditions of a predetermined frequency and maximum amplitude, a steel sheet excellent in hydrogen embrittlement resistance could be manufactured.

[Table 1]

[Table 2-1]

[Table 2-2]

According to the continuous annealing device, the continuous hot dip galvanizing device, and the steel sheet manufacturing method of the present invention, a steel sheet with excellent hydrogen embrittlement resistance can be manufactured without impairing production efficiency or changing mechanical properties.

100: Continuous annealing device
200: Continuous hot dip galvanizing device
300: Continuous hot dip galvanizing device
10: Pay-off reel
11: Welder
12: Cleaning equipment
13: entrance looper
20: Annealing furnace
22: heating table
24: crack zone
26: Cooling rack
26A: Cooling nozzle
28: Overaging treatment table
29 : Snout
30: Downstream equipment
31: Hot dip galvanizing bath
32: Gas wiping device
33: alloying furnace
34: Cooling device
35: exit looper
36: Temper rolling mill
50: Tension reel
60: Vibration additional device
61: controller
62: amplifier
63: electromagnet
63A: Magnet
63A1: magnetic pole surface
63B: Coil
64: Vibration detector
65: power
70: Vibration additional device
71: controller
72: Vibrator
73: Vibration detector
C: Cold rolled coil
S: cold rolled steel plate
P: product coil

Claims (33)

A pay-off reel for dispensing cold-rolled steel sheet from the cold-rolled coil,
An annealing furnace for continuously annealing the cold-rolled steel sheet by rolling it, wherein a heating zone, a cracking zone, and a cooling zone are located from the upstream side in the rolling direction, and in the heating zone and the cracking zone, the cold-rolled steel sheet is annealed in a reducing atmosphere containing hydrogen, In the cooling zone, an annealing furnace for cooling the cold rolled steel sheet,
a downstream facility that continuously distributes the cold rolled steel sheet discharged from the annealing furnace;
a tension reel for winding the cold rolled steel sheet being sold to the downstream facility;
For the cold-rolled steel sheet being sold from the cooling table to the tension reel, the frequency of vibration of the cold-rolled steel sheet is 100 Hz or more and 100,000 Hz or less, and the maximum amplitude of the cold-rolled steel sheet is 10 nm or more and 500 ㎛ or less. A continuous annealing device having a vibration adding device that preferably adds vibration. According to claim 1,
The vibration adding device is a continuous annealing device installed on the cooling table. The method of claim 1 or 2,
The vibration adding device is a continuous annealing device installed in a position capable of adding vibration to the cold rolled steel sheet being sold through the downstream facility. The method according to any one of claims 1 to 3,
A continuous annealing device wherein the arrangement of the vibration adding device and the sheet-threading speed of the cold-rolled steel sheet are set so that the time for adding vibration to the cold-rolled steel sheet is 1 second or more. The method according to any one of claims 1 to 4,
The vibration adding device has an electromagnet having a magnetic pole surface facing away from the surface of the cold rolled steel sheet, and is configured to cause the cold rolled steel sheet to vibrate due to an external force applied to the cold rolled steel sheet by the electromagnet. A continuous annealing device. The method according to any one of claims 1 to 4,
The vibration adding device has a vibrator in contact with the cold-rolled steel sheet, and is configured to cause the cold-rolled steel sheet to vibrate by the vibrator. The continuous annealing device according to claim 1,
The downstream equipment is located downstream of the annealing furnace in the plate-making direction, and has a hot-dip galvanizing bath for immersing the cold-rolled steel sheet and performing hot-dip galvanizing on the cold-rolled steel sheet. A continuous hot-dip galvanizing device. According to claim 7,
The vibration adding device is a continuous hot dip galvanizing device installed in a position capable of adding vibration to the cold rolled steel sheet being passed upstream of the hot dip galvanizing bath. According to claim 7 or 8,
The vibration adding device is a continuous hot dip galvanizing device installed in a position where vibration can be applied to the cold rolled steel sheet being passed downstream from the hot dip galvanizing bath. According to claim 7,
The downstream equipment is located downstream of the hot-dip galvanizing bath in a sheet-feeding direction, and has an alloying furnace for sheeting the cold-rolled steel sheet and heat-alloying the hot-dip galvanizing. According to claim 10,
The vibration adding device is a continuous hot dip galvanizing device installed in a position capable of adding vibration to the cold rolled steel sheet being passed upstream of the hot dip galvanizing bath. The method of claim 10 or 11,
The vibration adding device is a continuous hot dip galvanizing device installed in a position where vibration can be applied to the cold rolled steel sheet being passed downstream from the hot dip galvanizing bath. The method according to any one of claims 7 to 12,
A continuous hot dip galvanizing device wherein the arrangement of the vibration adding device and the sheet-threading speed of the cold-rolled steel sheet are set so that the time for adding vibration to the cold-rolled steel sheet is 1 second or more. The method according to any one of claims 7 to 13,
The vibration adding device has an electromagnet having a magnetic pole surface facing away from the surface of the cold-rolled steel sheet, and is configured to cause the cold-rolled steel sheet to vibrate due to an external force applied by the electromagnet to the cold-rolled steel sheet. A continuous hot-dip galvanizing device. . The method according to any one of claims 7 to 13,
The vibration adding device has a vibrator in contact with the cold-rolled steel sheet, and is configured to vibrate the cold-rolled steel sheet by the vibrator. (A) a process of dispensing a cold-rolled steel sheet from a cold-rolled coil using a pay-off reel;
(B) The cold-rolled steel sheet is passed through an annealing furnace in which a heating zone, a cracking zone, and a cooling zone are located from the upstream side of the rolling direction, and (B-1) in the heating zone and the cracking zone, in a reducing atmosphere containing hydrogen. A process of annealing a cold-rolled steel sheet and (B-2) performing continuous annealing of cooling the cold-rolled steel sheet in the cooling zone;
(C) a process of continuously selling the cold rolled steel sheet discharged from the annealing furnace,
(D) winding up the cold rolled steel sheet with a tension reel and forming a product coil in this order,
After step (B-2) and before step (D), with respect to the cold rolled steel sheet being sold, the frequency of vibration of the cold rolled steel sheet is 100 Hz or more and 100,000 Hz or less, and the maximum frequency of the cold rolled steel sheet is 100,000 Hz or less. A method of manufacturing a steel plate including a vibration addition process of adding vibration so that the amplitude is 10 nm or more and 500 μm or less. According to claim 16,
The method of manufacturing a steel plate in which the vibration addition process is carried out in process (B-2). The method of claim 16 or 17,
The method of manufacturing a steel plate in which the vibration addition process is performed in process (C). According to claim 16,
Step (C) includes the step of (C-1) immersing the cold-rolled steel sheet in a hot-dip galvanizing bath located downstream in the sheet-feeding direction of the annealing furnace, and hot-dip galvanizing the cold-rolled steel sheet. Manufacturing method. According to claim 19,
A method of manufacturing a steel plate, wherein the vibration addition process is performed before process (C-1). The method of claim 19 or 20,
The method of manufacturing a steel plate in which the vibration addition process is performed after the process (C-1). According to claim 19,
In the step (C), following the step (C-1), (C-2) the cold-rolled steel sheet is passed through an alloying furnace located downstream in the pass-through direction of the hot-dip galvanizing bath, and the hot-dip galvanizing is heated. A method of manufacturing a steel sheet, including an alloying process. According to claim 22,
A method of manufacturing a steel plate, wherein the vibration addition process is performed before process (C-1). The method of claim 22 or 23,
The method of manufacturing a steel plate in which the vibration addition process is performed after the process (C-1). The method according to any one of claims 16 to 24,
In the vibration addition step, a method of manufacturing a steel sheet, wherein the time for adding vibration to the cold rolled steel sheet is 1 second or more. The method according to any one of claims 16 to 25,
In the vibration addition step, the cold-rolled steel sheet is vibrated by an external force applied to the cold-rolled steel sheet by an electromagnet having opposite pole surfaces spaced apart from the surface of the cold-rolled steel sheet. The method according to any one of claims 16 to 25,
In the vibration addition step, the cold-rolled steel sheet is vibrated by a vibrator in contact with the cold-rolled steel sheet. The method according to any one of claims 16 to 27,
A method of manufacturing a steel sheet, wherein the cold-rolled steel sheet is a high-strength steel sheet having a tensile strength of 590 MPa or more. The method according to any one of claims 16 to 28,
The cold rolled steel sheet is expressed in mass%,
C: 0.030 to 0.800%,
Si: 0.01 to 3.00%,
Mn: 0.01 to 10.00%,
P: 0.001 to 0.100%,
S: 0.0001 to 0.0200%,
N: 0.0005 to 0.0100%, and
Al: Contains 0.001 to 2.000%,
A method for manufacturing a steel sheet, having a component composition where the balance consists of Fe and inevitable impurities. According to clause 29,
The above component composition is further expressed in mass%,
Ti: 0.200% or less,
Nb: 0.200% or less,
V: 0.500% or less,
W: 0.500% or less,
B: 0.0050% or less,
Ni: 1.000% or less,
Cr: 1.000% or less,
Mo: 1.000% or less,
Cu: 1.000% or less,
Sn: 0.200% or less,
Sb: 0.200% or less,
Ta: 0.100% or less,
Ca: 0.0050% or less,
Mg: 0.0050% or less,
Zr: 0.1000% or less, and
REM: 0.0050% or less
A method of manufacturing a steel sheet containing at least one element selected from the group consisting of. The method according to any one of claims 16 to 27,
The cold rolled steel sheet is expressed in mass%,
C: 0.001 to 0.400%,
Si: 0.01 to 2.00%,
Mn: 0.01 to 5.00%,
P: 0.001 to 0.100%,
S: 0.0001 to 0.0200%,
Cr: 9.0 to 28.0%,
Ni: 0.01 to 40.0%,
N: 0.0005 to 0.500%, and
Al: Contains 0.001 to 3.000%,
A method of manufacturing a steel sheet, which is a stainless steel sheet having a composition where the balance consists of Fe and inevitable impurities. According to claim 31,
The above component composition is further expressed in mass%,
Ti: 0.500% or less,
Nb: 0.500% or less,
V: 0.500% or less,
W: 2.000% or less,
B: 0.0050% or less,
Mo: 2.000% or less,
Cu: 3.000% or less,
Sn: 0.500% or less,
Sb: 0.200% or less,
Ta: 0.100% or less,
Ca: 0.0050% or less,
Mg: 0.0050% or less,
Zr: 0.1000% or less, and
REM: 0.0050% or less
A method of manufacturing a steel sheet containing at least one element selected from the group consisting of. The method according to any one of claims 16 to 32,
A method of manufacturing a steel sheet, wherein the product coil has an amount of diffusible hydrogen of 0.50 ppm by mass or less.

Images