JP5434764B2 - Cutting tool and bead cutting device - Google Patents

Description

The present invention relates to a bead cutting device for cutting a bead generated at the time of flash butt welding in a continuous rolling line of a steel sheet, and a cutting tool attached to the bead cutting device.

In a continuous rolling line for steel plates, flash butt welding is widely used to connect the rear end of the preceding steel plate and the front end of the subsequent steel plate. Flash butt welding consists of a flushing process and an upset process, and metal and slag are pushed out of the weld surface by a strong pressure welding in the upset process to form a bead. If the bead formed on the steel plate is left as it is, wrinkles are generated in the steel plate in the rolling process after flash butt welding, or the steel plate is broken. For this reason, the bead produced by flash butt welding is smoothly cut (flash trimmed) by a bead cutting device called a flash trimmer or a bead trimmer (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 63-116186

When the bead remains on the steel plate even as part of uncut residue or cutting waste after bead cutting, the rolling roll is wrinkled at the time of rolling the steel plate, and the wrinkle is continuously transferred to the steel plate and easily becomes a roll wrinkle. Therefore, in bead cutting, it is important that there is no uncut residue and that the cutting waste is removed smoothly.

FIG. 5 is a schematic diagram showing the cutting angle. Since the front surface of the cutting tool in the traveling direction plays a role of scooping off the cut swarf, it is called a rake surface. The angle between is called the rake angle. An angle for creating a space between the cutting tool and the workpiece is called a clearance angle. Generally, when the rake angle at the time of cutting is large (the clearance angle is small), the tip of the cutting tool tends to be chipped, leading to uncut parts of the bead. Conversely, if the rake angle is small (the relief angle is large), the cutting waste is not discharged smoothly, resulting in an increase in cutting resistance and a meandering of the cutting surface.

The present invention has been made in view of such circumstances, and an object thereof is to provide a cutting tool and a bead cutting device in which cutting waste is smoothly discharged and cutting resistance is small.

In order to achieve the above object, the first invention is mounted on a bead cutting device for cutting a bead generated when flash butt welding is performed on the rear end of a preceding steel plate and the front end of a subsequent steel plate in a continuous rolling line of the steel plate. in a cutting tool, the arc-shaped recess and a sectional side view is formed on the rake face, the opening width of the recess 7Mm～15mm, is and the maximum depth of the recess Ri 0.5mm~2.0mm der, side The cross-sectional view is characterized in that the distance from the tip of the blade portion to the start point of the recess is 2 mm to 6 mm .

When the opening width of the recess is less than 7 mm, the cutting waste is easily caught in the recess, and the cutting property of the cutting waste is deteriorated. On the other hand, when the opening width exceeds 15 mm, the cutting property of the cutting waste is deteriorated. On the other hand, when the maximum depth of the recess is less than 0.5 mm, the spiral diameter of the cutting waste becomes too large, whereas when the maximum depth exceeds 2.0 mm, the cutting resistance becomes too large.

If the distance from the tip of the blade to the starting point of the recess is less than 2 mm, the life until the chip of the blade is shortened. On the other hand, if the distance from the tip of the blade to the starting point of the recess exceeds 6 mm, The spiral diameter becomes too large.

Furthermore, the second invention is equipped with the cutting tool according to the first invention, and cuts a bead generated when the rear end of the preceding steel plate and the front end of the subsequent steel plate are flash-butt welded in the continuous rolling line of the steel plate. In the bead cutting device, the cutting tool has a rake angle of 5 ° to 17 °.

When the rake angle is less than 5 °, the cutting resistance becomes excessively large, whereas when the rake angle exceeds 17 °, the life until the cutting edge is shortened.

The cutting tool according to the present invention is provided with an arc-shaped recess on the rake face of the cutting tool in a side sectional view, the opening width of the recess is 7 mm to 15 mm, and the maximum depth of the recess is 0.5 mm to 2.0 mm. Furthermore, the bead cutting device to which this cutting tool is attached has a rake angle of 5 to 17 °, so that when cutting the bead, the cutting resistance is small, and the generated cutting waste is an arc-shaped recess. It is divided by rotating along a spiral. As a result, cutting waste is discharged smoothly.

It is a schematic diagram for demonstrating flash butt welding, (A) has shown the flushing process, (B) has shown the upset process. (A) is a front view of a tool holder to which a cutting tool is mounted, and (B) is a side view of the tool holder. (A) is a front view of a cutting tool according to an embodiment of the present invention, and (B) is a side view of the cutting tool. It is AA arrow sectional drawing of FIG. It is a schematic diagram for demonstrating a cutting angle.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.

A schematic diagram for explaining flash butt welding in a continuous rolling line for steel sheets is shown in FIG. In a first process called a flushing process, the voltage applied via the electrode 21 connected to the power source 20 is used to connect between the end faces of the continuous steel plates 11 (the rear end surface of the preceding steel plate and the front end surface of the subsequent steel plate). An arc is generated continuously (see FIG. 1A). The part where the arc is generated melts locally, and a part of the melted metal is released to the outside as spatter, but the rest remains on the end face of the steel plate 11. In the part melted by the arc, a dent called a crater is generated. The steel plate 11 is gradually approached, and arcs are successively generated at new contact portions, and the steel plate 11 is gradually shortened by repeated local melting.
By continuing the flushing process for several seconds to several tens of seconds, the entire end face of the steel plate 11 is melted. Further, the vicinity of the end surface of the steel plate 11 is softened by the temperature rise. When this state is reached, as shown in FIG. 1B, pressurization is performed in the longitudinal direction of the steel sheet (upset process). By this pressurization called upset, the crater formed on the end face of the steel plate 11 is crushed, and the molten metal existing between the end faces is pushed out of the weld face. In the vicinity of the softened end surface, plastic deformation is performed and the cross section increases, and a bead 22 is formed around the weld surface.

In the next step, the bead 22 generated by flash butt welding is cut smoothly by a bead cutting device (not shown) called a flash trimmer or a bead trimmer.
2A and 2B show an example of a bite holder 10 constituting a bead cutting device. The cutting tool holder 10 has a substantially rectangular parallelepiped shape, and is set so that the material axis is substantially perpendicular to the steel plate 11. In the lower part of the bite holder 10, a traveling direction X is formed and a recessed part 10a that opens downward is formed. The cutting tool 12 is attached to the recessed portion 10a so that the rake angle θ is 5 ° to 17 °.

The shape of the cutting tool 12 is shown in FIGS. When the cutting tool 12 is viewed from the front, the cutting tool 12 has a rectangular shape, and each corner portion 12a has a rounded shape (see FIG. 3A). Further, when the cutting tool 12 is viewed from the side, it has a substantially parallelogram shape, and the acute angle portions become the blade portions 17 and 18 (see FIG. 3B). The cutting tool 12 is formed in a point-symmetric shape when viewed from the side, and when the blade part 17 is worn, the cutting part 12 can be rotated 180 degrees when viewed from the side so that the blade part 18 can be used. it can. The cutting tool 12 is made of cemented carbide, high speed steel (high speed tool steel), or the like obtained by mixing and sintering tungsten carbide and cobalt as a binder.

The front and back surfaces of the cutting tool 12 are rake faces 13 and 14, respectively, at a position away from the tips of the blade portions 17 and 18 of the rake faces 13 and 14 by a predetermined cylindrical shape (circular shape when viewed from a side section). ) Recesses 15 and 16 are formed.

V-shaped groove portions 19 are formed on both side surface portions 12 b of the cutting tool 12, and inverted V-shaped protrusions (not shown) formed on the cutting tool holder 10 are fitted into the groove portions 19 of the cutting tool 12. Thus, the cutting tool 12 is mounted on the tool holder 10.

As shown in FIG. 4, there is an optimum range for the sizes and positions of the recesses 15 and 16, and as shown in FIG. If the depth is D, and the distance from the tips of the blades 17 and 18 to the starting points of the recesses 15 and 16 is L, W must be 7 mm to 15 mm, and D must be 0.5 mm to 2.0 mm. L is preferably 2 mm to 6 mm.

In addition, when the side cross section of the recessed parts 15 and 16 is a perfect circular arc, when the radius of curvature of the recessed parts 15 and 16 is R (mm), the following equation A relationship is established.
^{(R-D) 2 + W} 2/4 = R 2 (1)
From equation (1), the radius of curvature R is as shown in equation (2).
R = (4D ² + W ² ) / 8D (2)

A plurality of cutting tools were manufactured using the size and position of the recesses as parameters, and a bead cutting test was performed to evaluate each cutting tool. Table 1 shows a list of test results. The rake angle during the test was fixed at 9 °.
The cutting resistance value was measured by a load cell attached to a bead cutting device.
The life in the table is the number of days until the cutting edge is missing, and the number of online cuttings was evaluated as 200 times / day.
In addition, the evaluation of the severability of the cutting waste is evaluated by the number of troubles in which the cutting waste is caught in the recesses. Is 2 to 9 times, and Δ is 50 times when the number of troubles is 10 times or more.

In Reference Examples 1 and 2 , the distance L from the tip of the blade part to the start point of the recess is outside the range of 2 mm to 6 mm. In Comparative Examples 1 and 2, the maximum depth D of the recess is outside the range of 0.5 mm to 2.0 mm, and in Comparative Examples 3 and 4, the opening width W of the recess is outside the range of 7 mm to 15 mm.
From the same table, all the examples had low cutting resistance, the life until the cutting edge was chipped was 7 to 8 days, the helical diameter of the cutting waste was 13 mm to 22 mm, and the cutting chip cutting property was also good. On the other hand, Comparative Examples 1 and 4 had poor cutting severability, and Comparative Example 2 had high cutting resistance. Further, in Comparative Example 3, the cutting waste was caught in the concave portion, and cutting was impossible.

Also, the cutting width of the cutting tool is 12 mm, the maximum depth D of the recess is 1.7 mm, the distance L from the blade tip to the starting point of the recess is 5 mm, and the rake angle is a parameter. Carried out. Table 2 shows a list of test results.
From the table, in Comparative Example 5 in which the rake angle is less than 5 °, the cutting resistance is large, and in Comparative Example 6 in which the rake angle exceeds 17 °, the life until the cutting edge is chipped is shortened.

Although one embodiment of the present invention has been described above, the present invention is not limited to the configuration described in the above-described embodiment, and is within the scope of matters described in the claims. Other possible embodiments and modifications are also included. For example, in the above embodiment, the concave portions are formed on both the front and back surfaces of the cutting tool, but it goes without saying that the concave portions may be formed only on one surface. Moreover, in the said embodiment, although the cutting tool is made into the integral thing, it is good also considering a blade part as a different body.

DESCRIPTION OF SYMBOLS 10: Tool holder, 10a: Recessed part, 11: Steel plate, 12: Cutting tool, 12a: Corner part, 12b: Side part, 13, 14: Rake face, 15, 16: Recessed part, 17, 18: Blade part, 19 : Groove, 20: power supply, 21: electrode, 22: bead

Claims (2)

In a cutting tool attached to a bead cutting device for cutting a bead generated when the rear end of a preceding steel plate and the front end of a subsequent steel plate are flash-butt welded in a continuous rolling line of the steel plate,
An arcuate recess is formed on the rake face in a side view, the opening width of the recess is 7 mm to 15 mm, and the maximum depth of the recess is 0.5 mm to 2.0 mm . A cutting tool characterized in that the distance from the tip of the blade portion to the starting point of the recess is 2 mm to 6 mm. Mounted claim 1 Symbol placement of the cutting tool is in the bead cutting device for cutting the bead that occurs when the tip of the rear end and the following steel sheet of the prior steel in continuous rolling line of the steel sheet was flash welding,
A bead cutting device characterized in that a rake angle of the cutting bit is set to 5 ° to 17 °.

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