JPH105813A - Method for hot cutting of crop and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting method by which the shape of a cut surface in a joined part in continuous hot rolling, controlling the variation in the cutting angle of cutting tool smaller than in the conventional method and making the butting at the time of joining surer and a device therefor. SOLUTION: This crop cutting device consists of an inlet-side plate pressing device 16 and an outlet-side plate pressing device 17 in which a bar is moved while restraining it by a constant load of 3-15% of cutting load with an upper cutting tool 2, an lower cutting tool 3 and the plate pressing surface corresponding to the ascent and descent of the cutting tools on the line-symmetric position of respective upper and lower cutting tools to the bar and, when the cutting tool are opened to the thickness of the bar after cutting, the bar is released. The crop cutting device has a structure with which a cutting start angle βsatisfies -1.0<=β<=1.0 in the range of bar thickness of 25-50mm in order to reduce the variation in the cutting angle. By taking a plate pressing angle αas -1.0<=β<=4.0 deg., the variation in the cutting angle of the cutting tool is reduced and inconvenience due to the variation in the cutting angle of the cutting tool at the time of joining is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cutting a hot bar, in which the range of the cutting angle of the blade at the joining surface is reduced as compared with the conventional one, and the bar joining is more reliably performed. It is.

[0002]

2. Description of the Related Art As a crop cutting apparatus conventionally used in hot rolling, (a) a drum shear, (b) a pendulum shear, and (c) a 4-crank shear as shown in FIG. Can be The drum type is a method in which cutting is performed in synchronization with the bar speed by the rotation of the drum 4. The pendulum type is synchronized with the bar speed by the rotation of the swing frame 5 and the 4-crank is rotated by the rotation of the crank 9. This is a crop cutting device for performing cutting. Since all of them mainly aim at completely cutting the bar, there is no concept of controlling the shape of the cut surface, particularly the angle of the cut surface, and there is no cutting device having a plate holding device.

[0003]

However, in the hot-rolling continuous technology in which the bars are joined before the finish rolling and the finish rolling is continuously performed, the cutting surface of the blade for abutting the bars becomes important, and therefore, the crop is cut. It has been found that it is necessary to control the shape of the cut surface by the cutting device, in particular, the blade cutting angle θ within a variation range of −5 ° ≦ θ ≦ 5 ° to make joining more reliable. However, in a conventional drum-type shear, the blade cutting angle θ is θ = 2 ° ± 9 °, in a pendulum shear, θ = −2 ° ± 6 °, and in a 4-crank shear, the cutting angle is There was a problem that it was as large as about 11 °.

Accordingly, an object of the present invention is to provide a hot crop cutting method and apparatus which can advantageously solve the above-mentioned problems and reduce the angle and variation in cut surface.

[0005]

The gist of the present invention is as follows: (1) Bars cut by a crop cutting device are joined before finish rolling, and the crop is cut in a hot rolling continuous process of performing continuous hot rolling. In the device, the bar moves along with the vertical movement of the blade at the time of cutting while restraining the bar with the plate holding surface, and the gap between the blades opens to the bar thickness after cutting. A hot-crop cutting device having a plate holding device for opening the bar when the bar is opened, (2) a bar having a thickness of 25 mm to 50 mm using the hot-crop cutting device according to (1). A cutting start angle β, which is an angle of a blade surface with respect to a vertical line of a pass line, in a range of −1.0 ° ≦ β ≦ 1.0 ° when hot cutting is performed. , (3)
The plate holding angle α, which is an angle of the plate holding surface, is set to -1 ° to 4 ° with respect to the plane perpendicular to the blade.
Hot crop cutting method described in (4), board holding force,
The hot crop cutting method according to the above (2) or (3), wherein the load required for cutting the blade is 3 to 15%.

Hereinafter, the present invention will be described in more detail. First, the reasons for limiting each angle defined in the present invention will be described. As shown in FIG. 2, the shape of the cut surface is determined by the blade cutting angle θ, the steady portion length m, and the sag amount l. As a result of intensive studies on the cutting angle of the cutting surface of the cutting surface in order to obtain a good cutting surface, it was found that the cutting angle θ of the cutting surface is determined by the state in which cracks occur in the cutting surface as shown in FIG. . Formulating this blade cutting angle is shown as equation (1). tan ^-1 (C _max / m) + β-γ <θ <tan ^-1 (C _min / m) + β (1)

The first term of the equation (1) is as follows. As shown in FIG. 3, the blade is not cut from the cutting start angle β to the cutting end angle, but is cut at 0 °, that is, at an angle perpendicular to the pass line. The cutting angle, which is determined from the geometrical relationship between the clearance m and the length m of the stationary portion cut by the blade.

Although the angle of the blade with respect to the bar during actual cutting changes as shown in FIG. 4, the angle after the cutting start angle β changes because the bar is constrained by the blade. The amount is small and can be represented by the cutting start angle β. Here, the cutting start angle β in the second term is a positive direction in which cutting starts on the entry side with respect to the pass line vertical plane.

The upper limit of the cutting start angle β is similarly determined from the equation (1) on the condition that the maximum value of the blade cutting angle does not exceed 5 °, and is 1 °. On the other hand, if the cutting start angle β is smaller than −1 °, the sag amount 1 decreases as shown in FIG. 6B, and when the trailing end of the preceding material and the leading end of the succeeding material are butted, the butted surface decreases. Therefore, the lower limit is -1 °,
The range of the cutting start angle β is −1 ° ≦ β ≦ 1 °.

The cutting bar inclination angle γ of the third term is an angle at which the bar is deformed due to a bending moment due to a cutting load as shown in FIG. It is represented by 0 <γ <α (2) From this, the cutting portion bar inclination angle γ can be reduced by reducing the plate holding angle α.

However, there is an allowable range for the plate holding angle. The upper limit is determined from the condition that the upper limit of the bar inclination angle at the time of cutting does not exceed the upper limit of 5 °.
°. The lower limit is defined as the angle at which the plate holding surface is horizontal to the pass line, as shown in FIG. 7, when the bar is opened and the bar is not deformed. The inclination η is -1 ° because some shears may still be inclined 1 ° toward the entry side.

Next, when the range of the proper plate pressing force is examined, as shown in FIG. 8, a state in which the plate pressing force is distributed on the plate pressing surface, and a large force is distributed far away from the blade as shown in FIG. In this case, it is possible to distribute a large force in the vicinity of the blade as shown in FIG. 2B. If the bending moment when cutting the bar and the pressing force are balanced in this range, the effect of the pressing is exerted. As a result of a test in which the cutting load was the same and the plate pressing force was changed, if the cutting load was less than 3%, the plate pressing force was insufficient and unbalanced, and the plate pressing escaped as shown in FIG. Fig. 9
As shown in (a), there is a problem that the bar and the plate pressing surface do not sufficiently contact each other, and the plate is deformed. From these, FIG.
An appropriate plate holding force as shown in FIG.
It can be seen that it should be set to 15%.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described more specifically with reference to the following examples. FIG. 10 shows the shape of the vicinity of the blade constituted by the upper and lower blades, the entrance side plate pressing device, and the exit side plate pressing device. In this embodiment, FIG.
Apply this to the pendulum shears shown in. The pendulum shear is roughly divided into a cutting mechanism and a swinging mechanism, and has a structure linked by a main crank 9 rotated by a drive device including a main drive motor 19 and a speed reducer 20. The cutting mechanism comprises a swing frame 5 rotatably suspended on a first eccentric portion of a main crankshaft 9 rotated by a driving device, a lower blade 8 fixed to the frame,
An upper blade 7 rotatably suspended around the second eccentric portion of the main crankshaft and performing a vertical sliding motion within the frame. On the other hand, the swing mechanism includes a swing link 6 linked to the main crankshaft via a crank. FIG. 12 shows the structure diagram. With the rotation of the main drive motor, the main crank makes one rotation, the upper and lower blades wrap by eccentricity and cut the bar, and the rotation of the main drive motor is replaced by the swing of the swing frame via the swing link. Then, by controlling the rotation of the main drive motor at a speed synchronized with the running speed, the bar is cut in synchronization with the running speed of the bar when the bar is cut.

In this pendulum shear, the cutting start angle can be variously changed.
°, -0.5 ° at a bar thickness of 25 mm, and the bar opening angle is-
It is fundamentally designed to minimize the absolute value of the cutting angle to 1.5 °.

FIG. 13 shows the structure inside the swinging frame to which the plate holding device is applied. The plate holding angle can range from 1.5 ° at which the bar is horizontal to a maximum of 4 °, but the variation in cutting angle becomes smaller as the plate holding angle is reduced, as shown in equation (2). Therefore, the angle is reduced to a minimum of 1.5 °, and the length of 150 mm or more has a large angle of about 15 ° in order to prevent the bar from sticking. The plate holding device has a structure in which the bar can be restrained while maintaining a constant load with the movement of the upper and lower blades when cutting the bar, by using a hydraulic device 21 or the like sealed between the accumulator as a dedicated chamber in the tool rest. ing. In addition, the plate holding device performs a cylinder setting or the like that determines a movable range so that the plate holding device does not protrude from the blade so as not to restrain the bar when the gap after cutting becomes equivalent to the bar thickness.

If the blade clearance of this pendulum shear is controlled at a conventional level of 0.7 mm to 1.3 mm, when the blade cutting angle is maximized, the clearance is 1.3 mm, the maximum, and the stationary portion length is When the minimum bar thickness is 25 mm in a state where the bar thickness is 75% of the bar thickness, the cutting start angle is -0.5 °, which is 4.97 ° from the equation (1). Next, when the blade cutting angle is the minimum, the clearance is the minimum 0.7 mm,
The length of the steady portion is 37.5 mm when the maximum bar thickness is 50 mm, and the cutting start angle is 0.5 °, which is 0.6 ° from the equation (1).
At this time, the oil pressure may be controlled by the cutting load so that the plate pressing force is controlled within 3 to 15% of the cutting load. As described above, the blade cutting angle is controlled in the range of −5 ° to 5 °, and the plate holding device enables crop cutting without deforming the bar.

It should be noted that the present invention is not limited to only the above-described embodiment, and various changes can be made without departing from the spirit of the present invention.

[0018]

As described above, by using the plate holding device according to the present invention, the variation in the cutting angle of the blade can be controlled to be smaller than in the past, and the effect of more reliably performing the joining at the time of joining can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a shear used in a conventional hot rolling line.

FIG. 2 is an explanatory diagram of a cross-sectional view cut by a crop cutting device.

FIG. 3 is an explanatory diagram of an ideal state in which a bar material and a blade surface are cut at a right angle and a bar does not bend or deform;

FIG. 4 is an explanatory diagram of an angle change from the start of cutting to the opening of a bar.

FIG. 5 is an explanatory view showing a state in which a flat bar is deformed by a moment at the time of cutting and is restrained by a plate holding device.

FIG. 6 is an explanatory diagram of a butt shape when a cutting start angle is more than -1 ° and less than -1 °.

FIG. 7 is an explanatory diagram of a bar deformation state diagram when the plate holding angle is small.

FIG. 8 is an explanatory diagram of a load distribution by the plate holding device.

FIG. 9 is an explanatory diagram of a bar behavior due to a plate pressing force.

FIG. 10 is a schematic view of a crop cutting device of the present invention having a plate pressing device on the entrance side.

FIG. 11 is an overall view of a pendulum shear.

FIG. 12 is a diagram of a pendulum shear mechanism.

FIG. 13 is an explanatory diagram of one embodiment of the present invention in which a plate holding device is applied to a pendulum shear.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bar material 2 Upper cutter 3 Lower cutter 4 Drum 5 Swing frame 6 Swing link 7 Upper turret 8 Lower turret 9 Main crank 10 Crank 11 Tie rod 12 Crop 13 Joining surface 14 Leading end of trailing material 15 Trailing material tip 16 Entry side plate holding device 17 Outlet side plate holding device 18 Cutting load 19 Main drive motor 20 Reduction gear 21 Plate holding hydraulic cylinder

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hisashi Iribe, Oita, Oita, Oita, 1-chome, Oita Works Nippon Steel Corporation Oita Works (72) Inventor, Mitsuo Nihei 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture No. 7 Hitachi, Ltd. Electricity & Electricity Development Division (72) Inventor Yukio Hirama 7-2-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Electricity & Electricity Development Division (72) Inventor Kenichiro Tada Kanagawa Within Hitachi Machinery Engineering Co., Ltd., 1-284, Funakoshi-cho, Yokosuka-shi, Japan (72) Inventor Yoshio Takakura 3-1-1, Sakaicho, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd. Hitachi Plant

Claims (4)

[Claims] 1. A bar cutter cut in a hot rolling continuous process in which bars cut by a crop cutting device are joined before finish rolling and continuous hot rolling is performed. In addition, it has a plate holding device that moves while restraining the bar on the plate holding surface with the vertical movement of the blade at the time of cutting, and opens the bar when the gap between the blades is opened to the bar thickness after cutting. Hot crop cutting equipment. 2. A cutting start angle β which is an angle of a blade surface with respect to a vertical line of a pass line when starting cutting of a bar having a bar thickness of 25 mm to 50 mm using the hot crop cutting device according to claim 1. Is within a range of -1.0 ° ≦ β ≦ 1.0 °. 3. A plate holding angle α which is an angle of a plate holding surface.
The hot crop cutting method according to claim 2, wherein the angle is set to -1 ° to 4 ° with respect to the plane perpendicular to the blade. 4. The hot crop cutting method according to claim 2, wherein the plate holding force is 3 to 15% of a load required for cutting the blade.