JPH07178421A - Method for cutting side end part of steel strip - Google Patents

Abstract

PURPOSE:To ensure a fixed amount of cutting and to remove the defect on the end face with a small amount of cutting in cutting of the side end part of a steel strip which is moved for feeding. CONSTITUTION:At the time of cutting the side end part of the steel strip 2 which is moved for feeding by using a cutting edge, the turning shaft 8 of a freely turnable arm 5 for supporting the cutting edge is provided on the downstream side in the advancing direction of the steel strip, the arm 5 is overhung on the side of the steel strip, the center of the turning shaft 8 of the arm is put on the inside of the end part of the steel strip 2 and cutting is executed while pressing the cutting edge against the end part of the steel strip. In this way, the cutting edge can follow up to the oscillation of the steel strip taking cutting depth as constant, the generation of uncut part in the edge part is surely prevented and also the life of a cutting tool is prolonged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting side edges of a strip that is fed and moved.

[0002]

2. Description of the Related Art In a rolling process or a pipe-making process, a width of a strip and a defect of a strip end surface, for example, a sag generated in a shearing step which is a previous step is removed to adjust an end surface shape. In addition, in the case of a plated strip, the end face of the strip is cut in order to remove the plating layer or impurities adhering to the end face. There are the following three methods as typical conventional methods.

The first is a method of cutting both end portions of the strip 2 with a pair of cutters 1 as shown in FIG.
For example, Japanese Unexamined Patent Publication No. 61-14811 discloses a technique characterized by changing the rotational speed of the cutter in accordance with the change of the feed rate of the strip by the above-mentioned method to make the cutting speed substantially constant. An edge milling device or the like is used as the device.

Since this method cannot follow the wobbling of the strip in the width direction, it is necessary to add another device for preventing the wobbling of the strip in the width direction.

However, since the strip has a large bending camber in the longitudinal direction and a fluctuation in width, it is extremely difficult to suppress the shake in the width direction to an extremely small amount, and this shake does not stabilize the amount of cutting on both end faces. There is a possibility that overcutting or uncut residue may occur, and there is a problem that a constant cutting amount cannot always be secured.

Further, this method is suitable when the wall thickness is medium or thicker and the feeding speed of the strip is low, and the equipment cost is large.

A second method generally known as a method for cutting the end face of a strip is disclosed in, for example, Japanese Patent Laid-Open No. 58-9703.
As shown in FIG. 2 and disclosed in Japanese Patent Publication No. JP-A-2004-163, a plurality of sets of cutting devices each having a pair of cutting blades 4 are arranged, guide rolls 3 are provided in front and behind thereof, and both end portions of the strip plate 2 are cut to obtain a desired plate. To get the width.

As in the case of the first example, the second method also does not follow the widthwise runout of the strip plate 2, but prevents the widthwise runout by restraining the front and rear guide rolls 3. Then, the desired plate width is obtained by the position of the cutting blade fixed by the initial setting.

Therefore, when the strip plate swings in the width direction,
Over-cutting and uncut residue occur, and it is not always possible to secure a certain amount of cutting. In this method, in order to reduce the above-mentioned problems, it is necessary to increase the cutting amount to a certain extent or more, which limits the life of the cutting blade and the feeding speed of the strip.

In addition, there is a method in which the guide roll and the entire cutting device are arranged on one base and the base is floated in order to follow the shake in the width direction. However, since it becomes heavy, it can be applied when the strip is thick and wide, but the response is poor.

The third method is a method of pressing each bite individually by spring force so as to follow the swing of the strip. FIG. 3 shows the structure of one byte in this method.

In this method, the rotary shaft 8 of the arm 5 is arranged on the upstream side of the cutting blade 6 and the arm 5 is pressed by the spring 7, and the cutting blade 6 follows the swing of the strip plate 2. Although the position of No. 1 changes, the cutting force largely changes with the change of the cutting position, and it is not possible to obtain a constant amount of cutting, and there is a drawback that overcutting or uncutting occurs.

[0013]

A conventional method in which a rotatable arm for holding a cutting blade is pressed by a spring force so as to follow the swing of a strip plate is, as shown in FIG. The cutting force is P, of which the main cutting force is P ₁ , the back force is P ₃ , the distance from the rotation center A of the arm to the strip plate is l ₁ , and the distance from the A point to the cutting edge is the same. L ₃ , the pressing force of the spring is F, the vertical distance from the pivot point A of the arm to the point of action of the spring is l _F , the spring constant is k, the standard compression length of the spring is x _o , and the strip plate If the swing amount is Δx, the tensile strength of the strip is σ _B , the strip thickness is t, the moment around point A due to the cutting force is Mp, and the moment around point A due to the spring force is Ms, the spring Cutting force can be achieved by balancing the cutting force against the cutting force with point A as the center of moment. Because it is done, the following (1), (2)
The relation of formula is established.

[0014]

## EQU00001 ## Mp-Ms = 0 ... (1)

[0015]

[Formula 2] l _F · F- (l ₁ P ₁ + l ₃ P ₃ ) = 0 ... (2)

The relation of the cutting component force is set as P ₃ = ξP ₁ (ξ = constant), and if the change of the attitude (angle) of the cutting blade due to the rocking of the strip is ignored, the cutting main component force P ₁ is (3 ) Expression.

[0017]

[Equation 3] P ₁ = l _F · k · (x ₀ −Δx) / (l ₁ + Δx + l ₃ ) ... (3)

The cutting depth s is determined as follows by the main cutting force P _{1 with} C as a constant.

[0019]

S = C × P ₁ / (σ _B × t) ... (4)

That is, for a strip having a certain thickness t and a tensile strength σ _B , as shown in FIG. 5, which shows the relationship between the cutting depth and the swing of the strip when the strip is cut by the conventional method, as shown in FIG. Swing amount Δx
Changes in the main component force P _{1 as it} is, the cutting depth s also changes.

When the strip plate swings to the cutting blade side, heavy cutting is performed and the life of the cutting blade is shortened. When the strip plate swings to the escape side, the cutting depth becomes too small and finally. Will cause the remaining uncut.

Further, since the change of the cutting force and the change of the spring force with respect to the change of the rocking amount Δx of the strip plate are opposite to each other, it can be said that chattering easily occurs in the cutting.

The present invention solves the problems of the prior art, and the cutting blade follows the fluctuation of the width of the strip and the wobbling in the width direction of the strip to ensure a constant cutting amount. A method of cutting side edges of a strip for reliably removing defects on the end surface is provided.

[0024]

Means for Solving the Problems The gist of the present invention for achieving the above object is to provide a rotatable arm for holding a cutting blade when the side edge of a feeding strip is cut by the cutting blade. Is provided on the downstream side in the traveling direction of the strip plate, and the arm is overhung to the strip plate side so that the center of the rotation shaft of the arm is inside the end portion of the strip plate and the cutting blade is It is a side edge part cutting method of a strip characterized by cutting while pressing it against the edge part of a plate.

[0025]

That is, when cutting the side end of the strip to be fed and moved by using the cutting blade, the cutting blade is set so as to keep the main cutting force component P ₁ constant by following the swing of the strip. The rotation axis of the rotatable arm for holding is provided on the downstream side in the traveling direction of the strip plate, and the arm is overhung to the strip plate side so that the center of the rotation axis of the arm is inside the end portion of the strip plate. This is a cutting method characterized in that a moment due to a cutting force component and a moment of a pressing force due to a spring are balanced so that the amount of cutting is always substantially constant with respect to the swing of the strip.

That is, if the center of rotation of the arm is set to the rear of the cutting position, the increasing / decreasing direction of the cutting force moment and the increasing / decreasing direction of the pressing force moment due to the spring force are the same with respect to the swing of the strip, and the strip moves. Even if it moves and the force required for cutting changes, by appropriately selecting the spring constant of the spring that presses the arm holding the cutting blade, the moment to press the cutting blade can be changed equally by following it. You can
This makes it possible to make the cutting amount almost constant.

[0027]

EXAMPLE An example of the cutting method according to the present invention will be described below.
A description will be given with reference to the drawings.

In the cutting method of the present invention, as shown in FIG. 4, the cutting force applied to the end face cutting is P, the main cutting force is P ₁ , the back force is P ₃ , and the arm rotation center is from point A. The distance to the strip is l ₁ , the distance from the point A to the tip of the cutting blade is l ₃ , the pressing force by the spring is F, and the vertical distance from the pivot point A of the arm to the point of action of the spring is l _F , The spring constant is k, the standard reduction length of the spring is x _o , and the amount of rocking of the strip is Δ
x, the tensile strength of the strip is σ _B , and the strip thickness is t, the bite pressing force of the spring balances the moment A at the center of the moment, so cutting is performed. , (6) is established.

[0029]

## EQU00005 ## Mp-Ms = 0 ... (5)

[0030]

[Equation 6] l _F · F- (l ₁ P ₁ + l ₃ P ₃ ) = 0 ... (6)

The relationship of the cutting main component force is set as P ₃ = ξP ₁ (ξ = constant), and if the change of the bite posture (angle) due to the rocking of the strip is ignored, the cutting main component force P ₁ is It is expressed by the equation 3).

[0032]

[Formula 7] P ₁ = l _F · k · (x ₀ −Δx) / (l ₁ + Δx + l ₃ ) ... (7)

If the spring constant k is set so that k = P ₁ / l _F , the main cutting force component P ₁ will be constant regardless of the rocking amount Δx of the strip, and the cutting depth s will be Since C is a constant and is expressed by the equation (8), it can be held constant regardless of the swing amount Δx of the strip.

[0034]

S = C × P ₁ / (σ _B × t) ... (8)

That is, as shown in FIG. 6, the swing amount Δ of the strip plate
Since the main component force P ₁ does not change even if moved by x, the cutting depth s maintains a certain set amount (s = 0.1 mm in FIG. 6).

Further, the change in the cutting force with respect to the change in the swing amount Δx of the strip plate and the change due to the spring force are substantially the same if the spring constant k is appropriately selected as described above. This indicates that chattering is unlikely to occur in the cutting according to the method of the present invention, and shows a good cutting surface in actual use.

Further, according to the method of the present invention, it is known that the increase of the cutting component force due to the wear of the cutting tool or the like has little influence on the reduction of the cutting amount.

FIG. 7 shows an overall view of an embodiment in which the edge cutting device for a strip according to the present invention shown in FIG. 4 is installed in three stages on one side, for a total of six stages.

The strip 2 flows in the direction of the arrow from the left to the right in FIG. In this embodiment, three pairs of cutting devices 10 are arranged between the entrance / exit side guides 3 which are guide roller mechanisms.

Reference numeral 9 indicates a pressing roller device provided on the upper and lower sides of the strip plate 3 in three pairs, and has a function of preventing vertical vibration of the strip plate 2. The pressing roller 9 may be added or deleted depending on the situation of vertical vibration of the strip 2.

Since each cutting device has good followability as described above, it follows the rocking of the strip, the camber, etc. between the guide rollers 3, so that even one pair has sufficient cutting performance. By forming a pair, it is possible to secure a cutting amount in response to sudden blade chipping and wear of the cutting tool, and to combine a plurality of angles with the end face.

[0042]

According to the present invention, the shape of the edge portion of the strip plate is unavoidable in the left and right and the shape defect. Furthermore, when attempting to perform electric resistance welding of a plated strip, it is necessary to remove the plating from the end face.In the conventional method, the removed thickness of the plated part is not constant and unstable, and the remaining plated part does not remain. I couldn't avoid it.

The method of the present invention is directed to such problems.
The rotation axis of the arm that holds the cutting blade is provided on the downstream side in the traveling direction of the strip, and the overhang is made so that the center of the rotation axis of the arm is inside the end of the strip, and the cutting blade is By cutting while pressing it against the end, it is possible to follow the swing of the strip with a constant cutting depth, and it is possible to reliably prevent the occurrence of uncut edges at the edge and also the bite. The life of can be extended.

The above-mentioned excellent characteristics concerning the end face cutting can be obtained by, for example, performing the aluminum-plated steel material before the electric resistance welded pipe, by reducing the oxidized inclusions in the welded portion, remarkably lowering the welding defect occurrence rate, and increasing the product yield. And improve
The excellent effect of improving the toughness and workability of the welded part is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view showing a conventional side edge cutting method for a strip plate using an edge milling device.

FIG. 2 is a plan view showing a conventional method for cutting a side end portion of a strip plate using a cutting tool.

FIG. 3 is an explanatory diagram of a set of bite link mechanisms that presses a conventional bite with a spring force.

FIG. 4 is an explanatory view of a set of bite link mechanisms for pressing the bite of the method of the present invention with a spring force.

FIG. 5 is a drawing showing the relationship between the swing of the plate and the cutting depth in the case of the conventional method of pressing a cutting tool with a spring force.

FIG. 6 is a drawing showing the relationship between the swing of the plate and the cutting depth in the case of the example of the present invention.

FIG. 7 is a plan view showing an example of cutting side edges of a strip according to the present invention.

[Explanation of symbols]

 1 Milling device 2 Strip plate 3 Guide roll 4 Bit 5 Arm 6 Tip 7 Spring 8 Rotating shaft 9 Pressing roller 10 A set of cutting device

Claims (1)

[Claims] 1. When a side edge of a strip to be fed and moved is cut by using a cutting blade, a rotary shaft of a rotatable arm for holding the cutting blade is provided on a downstream side in a traveling direction of the strip. The band is characterized by overhanging the arm toward the strip plate side, making the center of the pivot axis of the arm inside the end portion of the strip plate, and cutting while pressing the cutting blade against the end portion of the strip plate. How to cut the side edges of a plate.