JPH05138431A - Cutting device for metallic plate - Google Patents

Abstract

PURPOSE:To provide a cutting machine which can prevent the work hardening of a cut part in the case of the trimming and slitting of a metallic plate. CONSTITUTION:A metallic plate cutting device has pinch rolls 3-1,3-2 which are provided at the inlet side or outlet side of a cutting machine and connected to a power source 5, and round cutting edges 1,2 which are assembled in the cutting machine and earthed, and directly applys electric current to a metallic plate 6 between the pinch roll and the round cutting edge for heating the metallic plate 6, and moreover has one pair or more of pinch rolls connected to the power source 5 and one pair or more of earthed pinch rolls on the inlet side or outlet side of the cutting machine, and directly applys the electric current to the metallic plate between both pairs of pinch rolls for heating the metallic plate. Thus the device is simple in construction and dispenses with a wide installing space, and moreover can be operated at a low cost because of its high energy efficiency. Since the metallic plate cut by this device is less in work hardening in a cut part (edge), the occurrence of edge cracking can be prevented in a cold rolling process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal plate cutting device for use in trimming for cutting off a width end portion of a metal plate, or slitting for cutting in multiple widthwise directions. The present invention relates to an apparatus capable of preventing or removing work hardening of a sheared portion of a metal plate.

[0002]

2. Description of the Related Art FIG. 4 ((a) shows a process for aligning the width of a metal plate.
Is a side view and (b) is a front view). This trimmer has an upper round blade 1 and a lower round blade 2
Set to a predetermined width by combining a pair of,
This is an apparatus for continuously shearing both ends of the metal plate 6 to separate a product 6-1 having a predetermined width and trim scraps 6-2 at both ends.

The separated trim waste 6-2 is processed by a device (not shown) called a scrap chopper or a scrap boller.

In the manufacturing process of a metal plate, for example, a steel plate, if cold rolling is performed after trimming is performed on a pickling line or a recoiling line, there is a problem that both end portions of the plate width are cracked. If this crack occurs, the rolled coil will not be a product and will cause a great deal of damage. One of the causes of such edge cracks during cold rolling is the local work hardening that occurs in the metal plate during the cutting process. For example, "Plasticity and Machining" Vo
Fig. 10 (B) on page 273 of l.20 No.219 (1979) shows an example of work hardening of the shearing part during slitting with a round blade. A local increase in hardness of Hv200 is observed near the processed edge. When cold-rolling the metal plate after trimming, cracks occur in the region of the end portion subjected to this work hardening.

As a method for solving these problems, JP-A-49-73357 discloses a device for heating the shearing portion of the strip steel plate provided between the trimmer and the cold rolling mill. A method of heating a sheared portion of a strip steel sheet to remove work strain and performing cold rolling is disclosed. According to this method, recrystallization is caused by heating the edge of the plate and the heating strain is removed, so that ductility is improved and edge cracking in cold rolling can be reduced. The means for local heating disclosed in the above publication is specifically induction heating or gas heating, and both are premised on being installed between the trimmer and the cold rolling mill. However, induction heating requires expensive equipment such as a high frequency power supply and a heating coil, and the heating efficiency is only about 50%, which increases the cost in terms of equipment and energy consumption. Further, when the temperature is raised by heat from the outside by gas heating, the surface temperature becomes extremely high due to heat input from the surface, and the oxidation due to the gas flame is also severe, so the deterioration of the surface quality of the product becomes a problem. Furthermore, in any of the above methods, stability of the heating plate of the heating section is required, and at the same time, additional equipment is required to cope with different widths of metal plates, and a large installation space is required. There are difficulties.

[0006]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems in the prior art, and does not cause local work hardening at the time of trimming or slitting. It is an object of the present invention to provide a cutting device in which operating costs are low and installation space is less problematic.

[0007]

According to the present invention, a metal plate is heated before cutting to reduce work hardening due to shearing.
Alternatively, the idea was to immediately heat the metal plate after cutting to remove the work hardening caused by shearing, and the gist of this is in the cutting devices (1) and (2) below.

(1) A metal plate cutting device comprising a pinch roll installed on the inlet side or outlet side of the cutting machine and connected to a power source, and a round blade incorporated in the cutting machine and grounded.

(2) A metal plate cutting device, characterized in that one or more pairs of pinch rolls connected to a power source and one or more pairs of grounded pinch rolls are provided on the inlet side or outlet side of the cutting machine.

FIG. 1 shows a trimming device as an example of the device of the present invention of the above (1). (A) is a side view, (b) is a side view.
Is a plan view. The metal plate 6 is continuously sheared by a pair of upper and lower round blades 1 and 2 while advancing in the arrow direction, and is separated into a product 6-1 and scraps 6-2 at both ends.

The apparatus shown in FIG. 1 has a pair of upper and lower pinch rolls 3-for feeding power to the inlet side (upstream side) of a cutting machine (trimmer).
There are 1 and 3-2. At least one of the pinch rolls is connected to the power supply 5. The power supply 5 may be a DC power supply or an AC power supply. Two or more pairs of pinch rolls may be provided. The upper and lower round blades 1 and 2 are grounded (earthed) to keep the potential zero at all times. The pinch roll is shown in FIG.
It is also possible to sandwich only both ends of the metal plate as shown in 3-1 and 3-2 in (b).

The upper and lower round blades 1 and 2 may be grounded by any method. For example, a conductive brush made of copper alloy is pressed against the shaft supporting the round blades. , This brush can be connected to a part of the housing.

When the metal plate 1 is passed through the trimming device having the above-mentioned structure and power is supplied by using the pinch rolls, the portion between the portion in contact with the pinch rolls and the portion (cutting portion) bitten by the upper and lower round blades is cut. Electricity flows through and heat is generated to generate Joule heat. Because there is a distance between the pinch roll and the round blade,
During that time, the effective resistance of the metal plate is large and a sufficient amount of heat generation can be obtained. Further, the temperature can be easily adjusted by changing the voltage or current applied to the pinch roll. When the temperature of the heating part is controlled with high accuracy, it is desirable to use the device of the present invention together with the temperature sensor.

Since the metal plate is running, the temperature rises as it gets closer to the blade, and the cutting portion that is bitten by the round blade and subjected to shearing is intensively heated. It can be effectively softened.

2A and 2B show an example of another trimming device according to the present invention. FIG. 2A is a side view and FIG. 2B is a plan view. In this example, pinch rolls 3-1 and 3-2 for power feeding are installed on the output side (downstream side) of the metal plate. Grounding the upper and lower round blades incorporated in the cutting machine (trimmer) is the same as in the device of FIG. Pinch roll
Although 3-1 and 3-2 are set so as to sandwich only both ends of the product, they may sandwich the entire width as shown in FIG.

Also in this apparatus, electricity is supplied between the part of the metal plate 6 that is inserted into the upper and lower round blades and the part that is sandwiched by the pinch rolls, and the end of the plate is heated. In this case, the highest temperature is due to the fact that the material is advancing and the temperature dependence of the electrical resistance, and the pinch roll 3-1 on the trimmer exit side,
It is the part sandwiched between 3-2. Therefore, the edge of the plate that is sheared by the round blade and work-hardened is immediately locally heated and softened, and the work strain is removed.

As shown in FIG. 2 (b), in the case of a device in which the pinch rolls sandwich only both ends of the metal plate, if the plate width of the metal plate changes, the pinch rolls 3-1 and 3-2 will be changed accordingly. Since it is necessary to move it to the end of the cutting portion, the equipment is more complicated than the device of FIG. 1 described above, but the energy efficiency is high because electricity can be concentrated on only the required portion.

FIG. 3 shows an example of a trimming device corresponding to the device of the present invention described in (2) above. Similar to FIG. 1 and FIG.
(a) is a side view and (b) is a plan view. In this device, the metal plate between two pairs of pinch rolls (a pair consisting of 3-1, 3-2 and a pair consisting of 4-1 and 4-2) is energized without using the round blade as an electrode. It is a device. That is, the power supply pinch roll 3-connected to the power source 5 on the inlet side (upstream side) of the trimmer
The pinch rolls 4-1 and 4-2, which are grounded (grounded), are located near the bite position of the trimmer 1 and 3-2. In this apparatus, the metal plate 6 between the pinch rolls 3-1 and 3-2 and the pinch rolls 4-1 and 4-2 is energized to heat the plate ends. In this case, the highest temperature is the part sandwiched between pinch rolls 4-1 and 4-2, and the shearing is performed by the round blade of the trimmer while only the plate edge is heated to high temperature. It becomes possible to suppress work hardening. Also in this case, the pinch roll may have a length sandwiching the entire plate width as shown in FIG. 1 (b). As shown in Fig. 3 (b), when the pinch roll has a structure that sandwiches only both ends of the plate, the pinch roll changes when the cutting width of the metal plate changes.
It is necessary to adjust the presser positions of 4-1 and 4-2 to the plate width end.

The heating method using two pairs of pinch rolls shown in FIG. 3 can also be carried out on the exit side of a cutting machine (in this case a trimmer). In this case, both ends of the trimmed metal plate are immediately heated to remove work hardening, as in the case of the apparatus shown in FIG.

The trimming device has been described above as an example, but in the case of multi-slitting, the necessary number of round blades of a cutting machine (slitting machine) are installed at appropriate intervals in the plate width direction. The structure is similar to that of the trimming device.

[0021]

In the apparatus of the present invention, the pinch roll sandwiching the metal plate and the round blade of the cutting machine are used as electrodes, or two or more pairs of pinch rolls installed before or after the round blade are used as electrodes on the metal plate itself. A direct heating method that energizes is adopted. By energizing the metal plate in this manner, Joule heat is used to locally heat and cut only the part to be cut by the upper and lower round blades, or locally heated after cutting,
It is possible to minimize the processing strain of the metal plate.

As described above, there is an induction heating method as one of heating methods, but since a high frequency current is used for heating, the equipment is complicated and expensive, and the heating efficiency is low. Further, in the induction heating method, the temperature and the heating efficiency cannot be kept constant unless the gap between the heating coil and the material to be heated is kept constant, so that the flapping and the like of the metal plate during passage can be suppressed as much as possible, Equipment is needed to secure stable threading.

Since the apparatus of the present invention only adds a small diameter pinch roll to the line as shown in the embodiment, it does not require a large installation space and the existing equipment can be easily modified. The pinch roll may be non-driving, and the pressing pressure (the force for sandwiching the metal plate) may be as small as several kg per 1 mm of plate width, so that the structure is simple and compact. In the case of equipment already equipped with a pinch roll, it is also possible to use it by connecting it to a power source.

In the apparatus of the present invention, if the pressing pressure of the pinch rolls is properly maintained, the metal plates can be stably bitten by the upper and lower round blades and the contact state necessary for energization can be secured. Since the heat source is electricity, it is easy to accurately adjust the heating temperature by controlling the energization amount. Further, even if the width of the plate for cutting changes, it is only necessary to change the setting of a normal cutting machine, and no special auxiliary device is required. Moreover, since the energy efficiency of direct energization (the efficiency of converting the input electric energy into heat energy) is extremely high at about 90%, the operating cost is lower than that of the induction heating method.

[0025]

EXAMPLE Trimming was performed using the trimming device having the configuration shown in FIGS. As a comparative example, a conventional trimming device having no heating means was also used.

Table 1 shows the specifications of the trimmer and the conditions for electric heating. The electrode distance in Table 1 is the distance between the pinch roll and the round blade shown in FIGS. 1 to 3B or the distance between the pinch rolls. The same trimmer is used in both the comparative example and the example, and the only difference is the energizing means. The metal plate to be trimmed is a pickling material of a low carbon steel plate with a carbon content of 0.2% and a thickness of 2.3 mm.
The width was 490 mm (cut-off width on one side was 5 mm).

Trimming under the above conditions,
The temperature of the edge immediately adjacent to the position where the upper and lower round blades are engaged with the material to be cut (the exit position of the pinch rolls 3-1 and 3-2 in Example 2) is ± 7 ° C with respect to the target temperature of 700 ° C. The sex was extremely good. Under all conditions, there were no problems such as sparks, and the temperature change due to disturbance such as flapping of the plate was within ± 2 ° C.

The hardness of the cut end of the product after trimming was measured, and the maximum hardness is shown in Table 2. In the comparative example without heating, the hardness (trimming material hardness, Hv) 85 before trimming is 183.
And has risen significantly. This work hardening causes a crack in the next step of cold rolling. On the other hand, in the example of the apparatus of the present invention, the degree of curing is slight. When the product obtained in this example was cold-rolled, no ear cracking occurred at all.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

By using the apparatus of the present invention, the work hardening of the sheared portion caused by the conventional trimming and slitting is greatly reduced. The device of the present invention has a simple structure and is inexpensive, but has extremely excellent stability of heating at the time of passing the plate, and has high energy efficiency, and therefore can be operated at low cost. Needless to say, the device of the present invention can be used not only for cutting steel plates but also for cutting all metal plates that can be electrically heated.

[Brief description of drawings]

FIG. 1 is a view showing a trimming device which is one of the devices of the present invention, (a) is a side view and (b) is a plan view.

FIG. 2 is a view showing another example of one trimming device of the device of the present invention, (a) is a side view and (b) is a plan view.

FIG. 3 is a view showing still another example of one trimming device of the device of the present invention, (a) is a side view and (b) is a plan view.

4A and 4B are diagrams illustrating a conventional trimming device, in which FIG. 4A is a side view and FIG. 4B is a front view.

[Explanation of symbols]

1, 2: Round blade, 3-1,3-2,4-1,4-2: Pinch roll,
5: Power supply, 6: Material to be cut (metal plate), 6-1: Product after cutting, 6-2: Trim waste

Claims (2)

[Claims] 1. A cutting device for a metal plate, comprising: a pinch roll installed on an inlet side or an outlet side of a cutting machine and connected to a power source; and a round blade incorporated in the cutting machine and grounded. 2. An apparatus for cutting a metal plate, comprising one or more pairs of pinch rolls connected to a power source and one or more pairs of grounded pinch rolls on an inlet side or an outlet side of a cutting machine.