JP3334544B2 - Warm slitting method and equipment for high silicon steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for warm slitting a high silicon steel strip and a warm slitting facility suitable for carrying out the method.

[0002]

2. Description of the Related Art Since a high silicon steel strip containing 4% or more of Si is very brittle, when it is slit at normal temperature, cracks and cracks are liable to occur in a shear plane. For this reason, the slit processing of the high silicon steel strip is performed in a warm (50
℃ or more). Conventionally, in order to perform such a warm slitting process, a heater is provided on an entrance side of a slit cutter blade to heat a steel strip.

[0003]

However, even in such conventional warm slitting, there is a problem that burrs and cracks are inevitably generated on the sheared surface after the slitting. In particular, since the occurrence of burrs and cracks in this shear plane is very unstable and changes over time, it is necessary to measure the height of the burrs after slitting over the entire length of the steel strip and remove the high burrs. As a result, the product yield and processing efficiency in slit processing have been significantly reduced. Therefore, an object of the present invention is to provide a warm slitting method and equipment capable of appropriately preventing the occurrence of burrs and cracks on a shear surface in warm slitting of a high silicon steel strip.

[0004]

The warm slit method and equipment of the present invention for solving such problems have the following features. (1) In the method of slitting a high silicon steel strip having a Si content of 4 to 8% at a plate temperature of 50 ° C. or higher, the temperature of the upper cutter shaft and the lower cutter shaft that hold the cutter blade for slitting. And controlling the temperature difference ΔT between both cutter shafts so as to satisfy the following expression. ΔT ≦ 3.6 × 10 ³ / W where ΔT: Temperature difference between upper and lower cutter shafts (° C.) W: Width of steel strip to be processed (mm)

(2) In a warm slit facility for carrying out the above method (1), a cooling mechanism for flowing a refrigerant inside an upper cutter shaft and a lower cutter shaft which hold a cutter blade for slitting. And a control mechanism for individually adjusting the flow rate and / or the temperature of the refrigerant supplied to each of the cooling mechanisms of the upper and lower cutter shafts. . (3) In the warm slit facility for carrying out the method of the above (1), a cooling gas is blown to each cutter shaft in opposition to the upper cutter shaft and the lower cutter shaft that hold the cutter blade for slit processing. A high-silicon gas nozzle having a cooling gas nozzle and an adjusting mechanism for individually adjusting a flow rate and / or a temperature of a cooling gas supplied to each of the gas nozzles facing the upper and lower cutter shafts. Warm slitting equipment for steel strip.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to the method of the present invention, the Si content is 4 to 8
% High-silicon steel strip is subjected to a slitting process at a hot plate temperature of 50 ° C. or higher. 4% Si content
Even if the steel strip is less than a cold strip, there is no burrs or cracks on the sheared surface even when the slit is cold, and it is not necessary to perform the hot slit. On the other hand, a steel strip having a Si content of more than 8% is remarkably brittle and has inferior magnetic properties, and thus is excluded from the scope of the present invention. Further, when the sheet temperature of the steel strip is less than 50 ° C., it is difficult to properly prevent burrs and cracking of the shear surface even if the method of the present invention is applied. Although the upper limit of the steel strip temperature in the warm slitting is not particularly specified, an insulating coating is usually applied to the silicon steel strip, and when the steel strip is heated above the heat-resistant temperature of the insulating coating, the coating is discolored. Or peeling. For this reason, in the case of a steel strip to which an organic coating containing an organic resin is applied, the upper limit of the steel strip sheet temperature is preferably about 300 ° C.

The inventors of the present invention have investigated and examined the causes of irregular burrs and cracks in the sheared surface during the hot slitting of a high silicon steel strip. It has been found that this is due to the thermal expansion of the heated cutter shaft. That is, when hot slitting a high silicon steel strip, the steel strip is heated in advance by a heater or the like, but the heat of the steel strip also heats the cutter shaft itself, and the temperature increases with the elapse of the slitting time. Go. When the temperature of the cutter shaft rises, the cutter shaft itself expands in the axial direction due to thermal expansion, so that the initially set clearance of the cutter blade changes, and the change in the clearance causes burrs or cracks on the shearing surface. Was found to occur irregularly.

The present inventors have studied what causes the change in the clearance of the cutter blade. Even if the cutter shaft is extended due to thermal expansion, the clearance does not change as long as the upper and lower shafts are extended equally. However, in practice, burrs and cracks occur on the shear surface. Therefore, hot slit processing was performed at various steel strip heating temperatures, and the temperature was measured by contacting a thermometer with the upper and lower cutter shafts during processing. As a result, as shown in Table 1, there was a large temperature difference between the upper and lower cutter shafts. It turned out that there is. Therefore, it was presumed that such a temperature difference between the upper and lower cutter shafts changed the clearance of the cutter blade, causing burrs and cracks in the shear surface.

[0009]

[Table 1]

In view of the above, a cooling mechanism is provided for allowing the refrigerant to flow inside the upper and lower cutter shafts, and the flow rate of the refrigerant to be supplied to each cutter shaft can be controlled separately. Was subjected to warm slitting while changing the temperature difference in various ways, and at that time, the height of burrs generated on the shear surface was measured. Table 2 shows the results, and it can be seen that the burr height decreases as the temperature difference between the upper and lower cutter shafts decreases. From such a result, if there is a temperature difference between the upper and lower cutter shafts, the thermal expansion amounts of the upper and lower cutter shafts are different. Therefore, as shown in FIG. It is considered that the clearance, which is the distance between the upper cutter blade and the lower cutter blade, changes with time due to the change in the relative position of the cutter blade. Therefore, it is considered that due to such a change in clearance over time, burrs generated on the shear surface also increase with the passage of the slit time.

[0011]

[Table 2]

[0012] Further, the present inventors performed warm slitting of steel strips having different widths and thicknesses to examine other factors affecting the burr generation, and the temperature difference between the upper and lower cutter shafts. The relationship between steel strip width and thickness and burr generation was investigated. As a result, the steel strip thickness has almost no effect on burr generation, but the steel strip width has a large effect on burr generation in relation to the temperature difference between the upper and lower cutter shafts, specifically, the upper and lower cutter shafts. When the temperature difference and the steel strip width are in the region as shown in FIG. 1 (the region without burrs in the figure), that is, the temperature difference ΔT between the upper and lower cutter shafts and the steel strip width W are expressed by the following formula (1). At a certain point, it was found that the burr height of the shearing surface was 20 μm or less, which was practically no problem in securing the space factor. ΔT ≦ 3.6 × 10 ³ / W (1) where ΔT: temperature difference between upper and lower cutter shafts (° C.) W: steel strip width of the steel strip to be processed (mm) The conditions are such that the temperatures of the upper cutter shaft and the lower cutter shaft holding the cutter blades are controlled such that the temperature difference ΔT between the two cutter shafts satisfies the above equation (1).

In carrying out the method of the present invention, it is necessary to control the temperature of the cutter shaft by some method. In the course of the tests and examinations described above, a cooling structure (for example, a water-cooling structure for flowing cooling water) through which the coolant flows inside the cutter shaft, and while measuring the temperature of the cutter shaft with a thermometer, the flow rate of the coolant and / or Alternatively, it was found that the cutter shaft temperature could be controlled within the above range by controlling the temperature. Therefore, in carrying out the method of the present invention, for example, cooling mechanisms for circulating the refrigerant are provided inside the upper and lower cutter shafts holding the cutter blades for slitting, and the cooling mechanisms are supplied to the respective cooling mechanisms. It is preferable to provide an adjusting mechanism capable of individually adjusting the flow rate and / or the temperature of the refrigerant, and to control the temperature of each cutter shaft by such a mechanism.

FIG. 2 shows an example of equipment suitable for controlling the temperature of the cutter shaft.
Reference numerals a and 2b denote cutter blades, and reference numerals 3a and 3b denote cutter shafts for holding upper and lower cutter blades. Each of the cutter shafts 3a and 3b is a cooling mechanism (for example, a water-cooled structure) for circulating a refrigerant therein. have. Also, 4a, 4
b is a supply pipe for supplying refrigerant to the cooling mechanism of each cutter shaft 3a, 3b, 5a, 5b is a flow control valve provided in each supply pipe 4a, 4b, 6 is a refrigerant supply device, and 7a, 7b is each cutter. A thermometer 8 for detecting the temperature of the shafts 3a and 3b controls the opening of the flow control valves 5a and 5b based on the detected temperatures of the thermometers 7a and 7b, and cools the cutter shafts 3a and 3b. A control device for controlling the amount of refrigerant supplied to the mechanism, wherein the flow control valves 5a and 5b, the refrigerant supply device 6 and the control device 8 adjust the flow rate of the refrigerant supplied to the cooling mechanism inside each cutter shaft. And an adjusting mechanism that can be used. There is no particular limitation on the cooling mechanism inside each cutter shaft and the structure for flowing the coolant through the cooling mechanism. For example, a known structure generally used for a water-cooled roll or the like may be used.

According to such equipment, the supply pipes 4a, 4
b, the coolant is supplied to each of the cutter shafts 3a, 3b, and the respective thermometers 7a, 7b provide the respective cutter shafts 3a, 3b.
3b is sequentially detected, and the detected temperature is
Is output to The steel strip width W of the steel strip currently being slit is input to the control device 8 in advance. The controller 8 calculates the temperature difference ΔT between the cutter shafts 3a and 3b, and calculates, for example, a deviation (3.6 × 10 ³ / W) −ΔT between 3.6 × 10 ³ / W and the temperature difference ΔT. When the value falls below a preset allowable value, the refrigerant supply amount is controlled by adjusting the opening of each of the flow control valves 5a and 5b so that the deviation becomes equal to or more than the allowable value. This allows the upper and lower cutter shafts 3
The temperatures of a and 3b can always be controlled so as to satisfy the above equation (1).

Further, as another example of the equipment, each of the cutter shafts 3 is provided in the middle of the refrigerant supply device 6 or each of the supply pipes 4a and 4b.
The temperature control mechanism of the refrigerant supplied to the supply pipes 4a, 3b is provided instead of or together with the adjustment of the refrigerant supply amount by the flow control valves 5a, 5b.
4b, the temperature of the refrigerant supplied to the cooling mechanism of each cutter shaft can be adjusted, and the controller 8 controls the temperature difference Δ between the two cutter shafts 3a and 3b in the same manner as described above.
T is determined, and when, for example, the difference between 3.6 × 10 ³ / W and the temperature difference ΔT (3.6 × 10 ³ / W) −ΔT falls below a predetermined allowable value, the deviation is determined to be allowable. By controlling the temperature adjustment mechanism so that the value of the
The temperature of the refrigerant to be supplied to a and 3b is controlled, or in parallel with the control of the refrigerant temperature, the amount of the refrigerant supplied is controlled by adjusting the opening of each of the flow control valves 5a and 5b. This makes it possible to control the temperatures of the upper and lower cutter shafts 3a and 3b so as to always satisfy the above equation (1).

FIG. 3 shows another example of equipment, in which gas nozzles for blowing a cooling gas (for example, air) to upper and lower cutter shafts are provided opposite to the respective cutter shafts 3a and 3b, and upper and lower gas nozzles are provided. An adjusting mechanism capable of individually adjusting the flow rate and / or the temperature of the cooling gas supplied to the cutter is provided, and the temperature of each cutter shaft can be controlled by such a mechanism. In the figure,
9a and 9b are gas nozzles provided to face the respective cutter shafts 3a and 3b, 10a and 10b are supply pipes for supplying cooling gas to the gas nozzles 9a and 9b, 11
a and 11b are flow control valves provided in the supply pipes 10a and 10b, 12 is a cooling gas supply device, 13a and 13b are thermometers for detecting the temperatures of the cutter shafts 3a and 3b,
A control device 14 controls the opening of the flow rate control valves 11a and 11b based on the detected temperatures of the thermometers 13a and 13b, and controls the amount of cooling gas supplied to the gas nozzles 9a and 9b. The flow control valves 11a and 11b, the cooling gas supply device 12, and the control device 14 constitute an adjustment mechanism that can adjust the flow rate of the cooling gas supplied to each gas nozzle. The upper and lower gas nozzles 9a, 9b
It is preferable to provide a plurality of cutters along the longitudinal direction of the cutter shafts 3a and 3b.

According to such equipment, the supply pipes 10a,
Cooling gas is supplied to the gas nozzles 9a and 9b through 10b, and the temperatures of the cutter shafts 3a and 3b are sequentially detected by the thermometers 13a and 13b, and the detected temperatures are output to the control device 14. The steel strip width W of the steel strip currently being slit is input to the control device 14 in advance.
In the control device 14, the temperature difference Δ between the two cutter shafts 3a, 3b
T is determined, and for example, 3.6 × 10 ³ / W
(3.6 × 10 ³ / W) −ΔT falls below a predetermined allowable value, the flow control valves 11a and 11b are controlled so that the difference becomes equal to or greater than the allowable value. The cooling gas supply amount is controlled through the opening degree adjustment.

As another control method, a cooling gas is not supplied in a normal state, and for example, 3.6 × 10 ³ /
Deviation between W and temperature difference ΔT (3.6 × 10 ³ / W) −ΔT
When the value falls below a preset allowable value, the supply of the cooling gas to at least one of the gas nozzles is controlled by opening and closing the flow control valves 11a and 11b and adjusting the opening so that the deviation becomes equal to or more than the allowable value. It may be performed. By the above method, the upper and lower cutter shafts 3a,
The temperature of 3b can be controlled so as to always satisfy the above equation (1).

As another example of the equipment, a temperature control mechanism for the cooling gas supplied to the gas nozzles 9a and 9b is provided in the cooling gas supply device 12 or in the supply pipes 10a and 10b. The temperature of the cooling gas supplied to each of the supply pipes 10a and 10b can be adjusted instead of or together with the adjustment of the cooling gas supply amount by 11a and 11b.
The temperature difference ΔT between the two cutter shafts 3a and 3b is obtained by the control device 14, and for example, 3.6 × 10 ³ / W and the temperature difference Δ
When the difference from T (3.6 × 10 ³ / W) −ΔT falls below a preset allowable value, the gas nozzle 9a is controlled by controlling the temperature adjusting mechanism so that the difference becomes equal to or more than the allowable value. , 9b, or in parallel with the control of the cooling gas temperature, each flow control valve 11
The control of the supply amount of the cooling gas is performed through the adjustment of the opening degrees of a and 11b. This makes it possible to control the temperatures of the upper and lower cutter shafts 3a and 3b so as to always satisfy the above equation (1).

[0021]

FIG. 2 shows a warm slitting equipment shown in FIG.
The cooling mechanism (water cooling structure) of the cutter shaft shown in Fig. 1 was adopted, and the hot slit processing was performed using this equipment. As a steel strip to be processed, 6.5% of 0.3mm thickness and 640mm width
Using steel sheet, steel strip temperature 180 ° C, line speed 20
14 slit processing was carried out at mpm. The temperature of the cutter shaft was measured by bringing a contact-type thermometer into direct contact with the cutter shaft and measuring the temperature difference between the upper and lower cutter shafts and adjusting the amount of cooling water supplied to the water cooling structure inside each cutter shaft.

As a result of performing the slitting while adjusting the temperature difference ΔT between the upper and lower cutter shafts so as to be maintained within 5.6 ° C. which always satisfies the above equation (1), shearing was performed over the entire length of the slit steel strip. The burr height of the surface could be suppressed to 20 μm or less. FIG. 6 shows the result. During the execution of the warm slitting, the temperature difference between the upper and lower cutter shafts was intentionally temporarily increased to 10 ° C., and as a result, the burr height temporarily increased during this time. In FIG. 6, the burr height is 20
In the part exceeding μm, the temperature difference of this cutter shaft is 1
This corresponds to the case where the temperature is increased to 0 ° C.

[0023]

According to the present invention described above, a high-silicon steel strip can be appropriately subjected to warm slitting without causing burrs or cracks in a shear plane.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the width of a steel strip and the temperature difference between an upper cutter shaft and a lower cutter shaft in a hot slit processing of a high silicon steel strip, in which a burr height of a shear surface is 20 μm or less.

FIG. 2 is an explanatory view showing one embodiment of the warm slit facility of the present invention.

FIG. 3 is an explanatory view showing another embodiment of the warm slit facility of the present invention.

FIG. 4 is an explanatory view showing the state of a cutter at room temperature and a cutter that has undergone thermal expansion.

FIG. 5 is an explanatory view showing a hot slit facility for a high silicon steel strip.

FIG. 6 is a graph showing the burr height of the sheared section of the steel strip subjected to slit processing in the example in the longitudinal direction of the steel strip.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Slit device, 2a, 2b ... Cutter blade, 3a, 3
b: cutter shaft, 4a, 4b: supply pipe, 5a, 5b: flow control valve, 6: refrigerant supply device, 7a, 7b: thermometer, 8
... Control device, 9a, 9b ... Gas nozzle, 10a, 10b
... supply pipes, 11a, 11b ... flow control valves, 12 ... cooling gas supply devices, 13a, 13b ... thermometers, 14 ... control devices

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shinichi Yamagishi 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Examiner, Nippon Kokan Co., Ltd. Motoki Takada (56) References JP-A-3-149116 (JP, A) Japanese Utility Model 63-158721 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23D 19/06

Claims (3)

(57) [Claims] 1. A method for slitting a high silicon steel strip having a Si content of 4 to 8% at a sheet temperature of 50 ° C. or higher,
A hot slitting method for a high silicon steel strip, characterized in that the temperatures of an upper cutter shaft and a lower cutter shaft which hold a cutter blade for slitting are controlled such that a temperature difference ΔT between both cutter shafts satisfies the following expression. . ΔT ≦ 3.6 × 10 ³ / W where ΔT: Temperature difference between upper and lower cutter shafts (° C.) W: Width of steel strip to be processed (mm) 2. A cooling mechanism for circulating a refrigerant inside an upper cutter shaft and a lower cutter shaft which hold a cutter blade for slit processing in a warm slit facility for performing the method according to claim 1. And a control mechanism for individually adjusting the flow rate and / or the temperature of the refrigerant supplied to each of the cooling mechanisms of the upper and lower cutter shafts. . 3. A warm slit installation for performing the method according to claim 1, wherein the upper and lower cutter shafts holding a cutter blade for slitting are opposed to each other.
A gas nozzle for spraying a cooling gas to each cutter shaft to cool it is provided, and an adjusting mechanism capable of individually adjusting the flow rate and / or temperature of the cooling gas supplied to each gas nozzle facing the upper and lower cutter shafts. Warm slitting equipment for high silicon steel strip, characterized by being provided.