JP5486261B2 - Cold rolling equipment and rolling method for electrical steel sheet - Google Patents

Description

  The present invention relates to a cold rolling facility for a magnetic steel sheet and a rolling method. It is improved so that the occurrence rate of the plate breakage is lowered.

  When an electromagnetic steel sheet (silicon steel sheet) is manufactured, the rate of occurrence of sheet breakage in the cold rolling process is high, which is a factor for reducing productivity. In an electromagnetic steel sheet, the relation between the steel sheet temperature and the crack sensitivity is inversely proportional. If the temperature of the steel sheet is high, the crack sensitivity is lowered and the occurrence rate of the sheet breakage is lowered. The specific copper plate temperature before rolling is 60 ° C. or more, and the occurrence rate of sheet breakage is low. Further, the steel plate temperature for passing the coil through the rolling mill or the tension reel is 60 ° C. or more, and the occurrence rate of the plate breakage is low.

Japanese Patent Application Laid-Open No. 03-052703 “Rolling Method and Equipment for Difficult-to-Work Materials” Japanese Patent Laid-Open No. 03-060813 “Warm Rolling Equipment” Japanese Patent Application Laid-Open No. 07-13212 “Cold rolling method of metal strip”

As a method for reducing the cracking susceptibility, it is known that a steel plate is heat-treated using a batch-type heating device, and then a heating coil is conveyed to a rolling facility and rolled.
As a batch heating method, there are a heating immersion tank method (Patent Document 1) in which a coil is put in a solution and heating, and a method (Patent Document 2) in which a coil is heated by an induction heating device.

The heating coil is generally transported using an overhead crane in the rolling mill building, and since the crane cannot be occupied, it is transported with sufficient margin in the rolling process, and the coil cools down with the rolling waiting time. It is necessary to heat more than necessary.
In addition, since a plurality of batch heating apparatuses are installed in the immediate vicinity of the payoff reel, it is difficult to secure space for equipment maintenance and secure a safety passage, and the entrance side of the rolling mill equipment tends to be complicated.

In addition, the solution is infiltrated into the coil layer in the heated immersion bath method, and when the coil is passed through a rolling mill or tension reel, the solution adheres to the rolling equipment from the surface of the steel plate, and the equipment is corroded. is there.
Furthermore, there is a problem that water vapor is generated from the surface of the steel plate, and the image processing of the control camera cannot be performed properly.

  Moreover, although patent document 3 etc. which install a heating apparatus just before a rolling mill are devised, the steel plate which passes the front installation of a heating apparatus is not heated only by it, and it is in a state with a high crack sensitivity. In front of the heating device, there is a straightening machine or the like that straightens the steel plate so that it can easily pass the steel plate having the curvature of the outer diameter of the coil.

  A cold rolling facility for an electromagnetic steel sheet according to claim 1 of the present invention that solves the above problems includes a rolling mill that cold-rolls the electromagnetic steel sheet, a pay-off reel that delivers an original coil to the rolling mill, and the rolling mill. In a rolling facility equipped with a straightening machine arranged between the payoff reel, a preheating device is provided on the payoff reel, and a heating device is provided before the rolling mill.

  The cold rolling equipment for electromagnetic steel sheet according to claim 2 of the present invention for solving the above-mentioned problems is characterized in that, in claim 1, the preheating device is a box type surrounding a drum and a coil of the payoff reel. To do.

  The cold rolling equipment for electromagnetic steel sheet according to claim 3 of the present invention for solving the above-mentioned problems is characterized in that, in claim 1 or 2, the preheating device is provided with a hot air heater.

  A cold rolling facility for an electromagnetic steel sheet according to a fourth aspect of the present invention for solving the above-described problems is the cold rolling facility for the magnetic steel sheet according to the first or second aspect, wherein the preheating device is provided with a hot liquid spray, and further, the payoff reel outlet side Is provided with a draining device.

  The cold rolling method for electrical steel sheets according to claim 5 of the present invention that solves the above-described problems uses the cold rolling equipment for electrical steel sheets according to claim 1, and the coil is moved by the preheating device at the payoff reel position. Preheating is performed, and further, the electromagnetic steel sheet is heated by the heating device in front of the rolling mill.

Since the coil is pre-heated by the pre-heating device at the payoff reel position, it is not necessary to consider the temperature drop due to the heating time of the heated coil and the rolling waiting time. In other words, it is not necessary to give extra energy.
Since the temperature is raised to about 20 ° C. by the pre-heating device at the payoff reel position, the subsequent heating time is not so much required. Therefore, only one heating device is required and a large installation space is not required.

The steel plate that passes through the straightening machine installed before the heating device before the rolling mill is preheated by the preheating device, and there is no problem of breaking the plate in the straightening machine that is the front equipment of the heating device.
If the preheating device is a box type surrounding the drum of the payoff reel, the coil can be efficiently heated.

If the preheating device is equipped with a hot air heater, there will be no residual solution of the steel plate, which is a problem in the heating and immersion tank method, so the solution from the steel plate surface adheres to the rolling equipment when passing through the rolling mill or tension reel. This eliminates the problem of equipment corrosion. Furthermore, since there is no water vapor generation from the steel sheet surface, the image processing of the control camera can be performed properly.
If the preheating device is equipped with a warm liquid spray, the heat transfer efficiency is good, so the heating time is short.

If the coolant liquid at the time of rolling is heated and used as the hot liquid, the warm liquid heating device is compatible and has low energy consumption.
By providing the draining device, there is no hot liquid residue on the steel sheet, and the problem of equipment corrosion and the problem of control camera image processing are eliminated.

It is the schematic which shows the cold rolling equipment for electromagnetic steel plates which concerns on Example 1 of this invention. It is the schematic which shows the cold rolling equipment for electromagnetic steel plates which concerns on Example 2 of this invention. It is the schematic which shows a rolling preparatory step (preheating of a payoff reel). It is the schematic which shows a rolling preparatory stage (pre-heating of a roll). It is the schematic which shows the rolling start time (1st pass). It is the schematic which shows during rolling (2nd pass and after). FIG. 7A is a process diagram showing a conventional heating method, and FIG.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments for carrying out the invention will be described with reference to the embodiments shown in the drawings.

FIG. 1 shows a cold rolling facility for electrical steel sheets according to Example 1 of the present invention.
As shown in FIG. 1, before and after a rolling mill 2 that cold-rolls an electromagnetic steel sheet (hereinafter simply referred to as a steel sheet) 9, a tension reel 3 that can wind and unwind a coil so that reversible rolling can be performed. 4 are disposed in front of the tension reel 3, and a payoff reel 1 for delivering the original coil and a straightening machine 5 for flatly correcting the electromagnetic steel sheet 9 having the curvature of the coil are disposed, and a preheating device is disposed at the payoff reel position. 6, and a heating device 7 is disposed between the rolling mill 2 and the tension reel 3.

The preheating device 6 has a box shape surrounding the drum of the payoff reel 1 and the original coil 8 and has a structure that can be opened and closed as indicated by a broken line in the drawing. Is provided with a hot air heater (not shown).
Further, the preheating device 6 is retracted from the payoff reel 1 when the steel plate 9 is dispensed (see FIG. 5).

The heating device 7 is an induction heating method whose temperature control is relatively simple.
Further, the heating device 7 can be disposed between the rolling mill 2 and the tension reel 3, and can also be disposed at a position between the rolling mill 2 and the payoff reel 1. When it is difficult to secure a space between the rolling mill 2 and the tension reel 3, it may be installed between the tension reel 3 and the straightening machine 5.
Further, the heating device 7 can also apply upper surface heating or simultaneous upper and lower surface heating in addition to the lower surface heating of the steel plate 9.
Although the rolling mill 2 used for a present Example is a 6-high mill, it is not restricted to this, For example, a 20-high cluster mill can also be applied.

The usage method (cold rolling method for electrical steel sheets) of the cold rolling facility for electrical steel sheets according to the present embodiment having the above configuration will be described with reference to FIGS.
3 and 4 show the rolling preparation stage.
First, as shown in FIG. 3, the payoff reel 1 is preheated by the preheating device 6. In the preheating, hot air of 200 ° C. to 300 ° C. is sent from the hot air heater into the box.

Next, as shown in FIG. 4, the coil 8 immediately after pickling is inserted into the payoff reel 1, and the payoff reel 1 and the coil 8 are heated by the preheating device 6.
In the inner layer portion of the coil 8, when the coil 8 is mounted on the payoff reel 1, the heat of the payoff reel 1 escapes to the coil 8 due to contact heat transfer between the coil 8 and the payoff reel 1, thereby increasing the temperature of the steel plate.
Further, the temperature of the outer layer portion of the coil 8 is increased by hot air of 200 ° C. to 300 ° C. in the box.

Accordingly, in the preheating, the inner layer portion and the outer layer portion of the coil 8 are mainly heated. This is because the temperature drop of the inner layer portion and the outer layer portion of the coil 8 is large during coil conveyance.
Here, the inner layer portion of the coil 8 refers to the leading end side of the steel plate 9 that is unwound from the payoff reel 1, and the outer layer portion of the coil 8 refers to the back of the steel plate 9 that is attached to the payoff reel 1 to the end. Say the end side. The front end side of the steel plate 9 refers to, for example, between the payoff reel 1 and the heating device 7, and the rear end side of the steel plate 9 refers to the opposite.

FIG. 5 shows the start of rolling (first pass).
First, as shown in FIG. 5, the preheating device 6 is retracted from the payoff reel 1 in order to unwind the steel plate from the payoff reel 1.
Next, the steel plate 9 having the coil curvature is straightened by the straightening machine 5.

At this time, the steel plate 9 is straightened by repeated bending, but the plate is not broken because it is preheated.
Thereafter, the steel plate 9 is heated to a temperature at which it does not break during rolling by a heating device 7 installed in front of the rolling mill 2. The steel plate 9 is rolled by the rolling mill 2, and the steel plate 9 is taken up by the tension reel 4.

FIG. 6 shows the rolling (after the second pass).
First, as shown in FIG. 6, the steel plate 9 is unwound between the tension reels 3 and 4, is rewound, and the steel plate 9 is repeated with the rolling mill 2 until a predetermined thickness is reached.
During this rolling, the pre-heating device 6 waits for the start of the next rolling while heating the payoff reel 1 and the next coil 8. When the heating device 7 is disposed between the rolling mill 2 and the tension roll 3, it is possible to heat the steel plate 9 during rolling (after the second pass).

When the rolling of the front coil is completed, the rolling of FIG. 5 is started, and these are repeated.
The above-described cold rolling method for electrical steel sheets according to the present embodiment will be described in comparison with the prior art with reference to FIG.

FIG. 7 (a) shows a conventional heating method, and FIG. 7 (b) shows the flow of heating work of the method of the present invention.
In the conventional heating method, as shown in FIG. 7A, after the steel plate is pickled, the coil is stored at room temperature in a coil yard, and the batch heating apparatus batch-heats the coil so that the steel plate is less susceptible to cracking. Rolling.

In other words, the steel sheet that was 70-80 ° C. in the pickling facility becomes 10-30 ° C. when stored at room temperature in the coil yard, is heated to 80-100 ° C. by the batch heating device, and then waits for coil conveyance and rolling. In this case, after the temperature reaches 60 to 80 ° C., it is rolled.
In this conventional heating method, if the rolling is started immediately after the coil conveyance, the temperature drop of the steel sheet is small, but the old coil is being rolled at the stage when the new coil is conveyed to the payoff reel, and the dedicated conveyance equipment for the coil is installed. If there is no coil, the coil is left on the payoff reel for about one hour at maximum, and the heat of the coil is radiated to the payoff reel and the outside air, and the temperature of the coil is lowered.

On the other hand, according to the method of the present invention, as shown in FIG. 7 (b), the coil is transported to the payoff reel immediately after the pickling of the steel sheet, and the pre-heating device (equipment before the rolling mill) is used while rolling the old coil. The coil can be heated to a temperature at which the plate does not break, and at the start of rolling, the coil can be heated before the rolling mill to a temperature at which the rolling does not break.
That is, the steel plate that was 70 to 80 ° C. in the pickling facility becomes 40 to 60 ° C. during coil conveyance, and is preheated to 60 to 80 ° C. by the preheating device in the rolling facility, and further, 60 by the heating device. After being heated to ˜80 ° C., it is rolled.

  Here, since the temperature drop of the inner layer portion and the outer layer portion of the coil 8 is large during coil conveyance, the inner layer portion and the outer layer portion of the coil 8, in other words, the tip side of the steel plate 9 and The rear end side is mainly heated.

FIG. 2 shows a cold rolling facility for electrical steel sheets according to Example 2 of the present invention.
The present embodiment relates to a rolling facility when the preheating device 6 of the payoff reel 1 is provided with a hot liquid spray.

  That is, the preheating device 6 is a box type surrounding the drum of the payoff reel 1 and the original plate coil 8, and the temperature of the coolant that has cooled the roll during rolling is further increased in the box type preheating device 6. A warm liquid spray (not shown) for feeding the warm liquid is provided.

Further, a draining device 10 is disposed between the payoff reel 1 and the straightening machine 5 in order to remove the hot liquid adhering to the steel plate surface.
Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals and redundant description is omitted.

The usage method (cold rolling method for electrical steel sheets) of the cold rolling facility for electrical steel sheets according to the present embodiment having the above configuration will be described with reference to FIGS.
3 and 4 show the rolling preparation stage.
First, as shown in FIG. 3, the payoff reel 1 is preheated by the preheating device 6.
In the preheating, a warm liquid of 80 ° C. to 90 ° C. is fed into the box and sprayed from a warm liquid spray.

As the hot liquid, a roll cooling coolant liquid at the time of rolling is further heated. The temperature of the coolant liquid that has cooled the roll is 50 ° C. to 60 ° C., and the temperature is raised from 80 ° C. to 90 ° C. with a temperature raising device.
In the inner layer portion of the coil 8, when the coil 8 is mounted on the payoff reel 1, the heat of the payoff reel 1 escapes to the coil 8 due to contact heat transfer between the coil 8 and the payoff reel 1, thereby increasing the temperature of the steel plate.

Further, the temperature of the outer layer portion of the coil 8 is increased by the hot liquid of 80 ° C. to 90 ° C. in the box.
Accordingly, in the preheating, the inner layer portion and the outer layer portion of the coil 8 are mainly heated. This is because the temperature drop of the inner layer portion and the outer layer portion of the coil 8 is large during coil conveyance.

Next, as shown in FIG. 4, the coil 8 immediately after pickling is inserted into the payoff reel 1, and the payoff reel 1 and the coil 8 are heated by the preheating device 6.
When the coil 8 is mounted on the payoff reel 1, the inner layer of the coil 8 causes the temperature of the steel sheet to rise due to the heat of the payoff reel 1 escaping to the coil 8 due to contact heat transfer between the coil 8 and the payoff reel 1.

Further, the outer layer portion of the coil 8 rises in temperature due to the hot liquid spray.
The hot liquid used for heating the payoff reel 1 and the coil 8 is collected in the box, returned to the cooler together with the coolant for roll cooling, and reused as coolant for roll cooling.

FIG. 5 shows the rolling start time (first pass).
First, as shown in FIG. 5, the preheating device 6 is retracted from the payoff reel 1 in order to unwind the steel plate from the payoff reel 1.
Moreover, the steel plate 9 passes the draining device 10 and the hot liquid adhering to the steel plate surface is excluded.

Next, the steel plate 9 having the coil curvature is straightened by the straightening machine 5.
At this time, the steel plate 9 is straightened by repeated bending, but is not ruptured because it is preheated.
The subsequent method is the same as that of the first embodiment shown in FIG.

[Contrast with Patent Documents 1, 2, and 3]
<Contrast with “Rolling Method and Equipment for Difficult-to-Work Materials” in Patent Document 1>
In patent document 1, since it is necessary to convey after a heating, a temperature fall must be considered and heating temperature becomes high.
On the other hand, in this invention, as shown in FIG.7 (b), since it preheats with a rolling installation (payoff reel part), it is not necessary to consider the temperature fall by conveyance.

  In the heating immersion bath method of Patent Document 1, the heating time of the coil is required for about 8 to 12 hours, and if one coil rolling time is 1 hour, 8 or more heating immersion baths are required for one shift operation. It becomes. For this purpose, a large facility installation space is required, and it becomes difficult to secure space for facility maintenance and secure a safety passage, and the entrance side of the rolling mill facility tends to be complicated.

On the other hand, in the present invention, since the temperature is raised to about 20 ° C. in the payoff reel section, the heating time is not so much, only one heating device is required, and a large installation space is not required.
In the heating immersion tank method of Patent Document 1, when the heating medium is a liquid, problems such as corrosion of equipment and water vapor are likely to occur, and image processing of the control camera cannot be performed properly.
On the other hand, in the present invention, since a draining device is provided on the payoff reel exit side, problems are unlikely to occur.

<Comparison with Patent Document 2 “Warm Rolling Equipment”>
In patent document 2, since it is necessary to convey after a heating, a temperature fall must be considered and heating temperature becomes high.
On the other hand, in this invention, since it heats with a rolling installation (payoff reel part), it is not necessary to consider the temperature fall by conveyance.

In the induction heating device of Patent Document 2, the coil heating time is required from about 0.25 to 2 hours, and if the time required for rolling one coil is 1 hour, two or more induction heating devices are required as the heating device. .
For that purpose, since a large installation space is required, it is difficult to secure a space for equipment maintenance and secure a safety passage, and the entrance side of the rolling mill equipment tends to be complicated.
On the other hand, in the present invention, it is sufficient to raise the temperature to about 20 ° C. at the payoff reel portion, so that the heating time is not so much, only one heating device is required, and a large installation space is not required.

<Contrast with “Cold rolling method of metal strip” in Patent Document 3>
In Patent Document 3, a heating device using thermal plasma is disposed in front of the rolling mill, but it is not heated before the heating device, and there is a problem of plate breakage.
In contrast, according to the present invention, since the pre-heating device is provided in the payoff reel portion, it is possible to prevent the plate from being broken by the straightening machine.

  INDUSTRIAL APPLICABILITY The present invention can be widely used industrially as a cold rolling facility and rolling method for electrical steel sheets that are improved so as to reduce the occurrence rate of sheet breakage.

DESCRIPTION OF SYMBOLS 1 Payoff reel 2 Rolling machine 3, 4 Tension reel 5 Straightening machine 6 Preheating apparatus 7 Heating apparatus 8 Coil 9 Electrical steel plate (steel sheet)
10 Drainer

Claims (5)

 In the rolling equipment provided with the rolling mill which cold-rolls an electromagnetic steel sheet, the payoff reel which pays out an original coil to the rolling mill, and the straightening machine arranged between the rolling mill and the payoff reel, the payoff reel A cold rolling facility for electrical steel sheets, wherein a preheating device is provided at the front and a heating device is provided before the rolling mill.  2. The cold rolling facility for electromagnetic steel sheets according to claim 1, wherein the preheating device is a box type surrounding a drum and a coil of the payoff reel.  3. The cold rolling equipment for electromagnetic steel sheet according to claim 1, wherein the preheating device is provided with a hot air heater.  3. The cold rolling facility for electrical steel sheets according to claim 1, wherein the preheating device is provided with a hot liquid spray, and further, a draining device is provided on the payoff reel outlet side.  Using the cold rolling equipment for electrical steel sheet according to claim 1, preheating the coil by the preheating device at the payoff reel position, and further heating the electrical steel sheet by the heating device in front of the rolling mill. A cold rolling method for electrical steel sheets.

Images