JP2018126814A - Cutting blade, cutting tool, slab care method and slab manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting blade, a cutting tool, a slab maintenance method and a slab capable of appropriately performing flat cutting of a workpiece having a hard surface layer on the surface side of a bare metal while extending the life of the cutting blade without being damaged. Provide a manufacturing method. A cutting blade 10 performs flat cutting of a work W having a hard surface layer W2 on the surface side of the bullion W1, and changes in the cutting depth direction from the surface layer W2 of the work W toward the bullion W1. It has a squeeze surface 13 having a squeeze angle, the bullion side squeeze angle α1 at the bullion side end 17a of the squeeze surface 13 is positive, and the surface of the surface layer W2 of the work W and the main cutting edge 17 on the squeeze surface 13 The boundary squeeze angle α3 at the intersecting boundary 17c is negative. [Selection diagram] Fig. 2

Description

  The present invention relates to a cutting blade used for plane cutting of a workpiece having a hard surface layer such as an oxide scale on the surface side of a bare metal, a cutting tool, a cutting blade, a slab care method using the cutting tool, and a slab manufacturing method. About.

Generally, a cutting tool such as a milling tool or an end mill is used for plane cutting of a workpiece. This cutting tool is mounted on a main spindle of a machine tool and applies a rotational force to a cutting blade by the rotation of the main spindle to cut a workpiece in a plane.
For example, in a milling tool, high-speed tool steel (commonly known as high-speed steel) or carbide is used as a cutting blade, and a plurality of cutting blades are attached to the cutter body. In recent years, each cutting blade can be easily attached to and detached from the cutter body, and what is called a throw away tip has become the mainstream.

When cutting a workpiece with this cutting tool, when cutting the surface of a workpiece that has a hard surface layer such as oxide scale on the surface side of the base metal, a so-called boundary is formed at a specific portion of the cutting blade by the hard surface layer. Local wear called wear may progress.
For this reason, when cutting the surface side of a workpiece having a hard surface layer such as an oxide scale on the surface side of the bare metal, a hard carbide tool is often used as a cutting blade.
However, when a harder carbide tool is used as the cutting blade, it is hard but has low toughness. For this reason, the edge (cutting edge) of the cutting blade may be pitched (blade spilled, chipped), and when cutting the surface side of a workpiece having a hard surface layer such as an oxide scale on the surface side of the bare metal, Boundary wear and pitching start at the part where the edge of the cutting blade and the surface layer of the workpiece come into contact with each other, and the blade tip may be broken starting from that point.

  On the other hand, as a processing method using a ball end mill that can perform scanning line processing into a high-precision three-dimensional shape like finishing even with a large axial cut amount such as rough processing for high-hardness steel materials, for example, patent What is shown in the literature 1 is known. This processing method is particularly effective for processing a steel material having a Vickers hardness of Hv400 or more.

JP, 2006-5860, A

However, the scanning line machining method using the ball end mill shown in Patent Document 1 is capable of high-precision scanning line machining into a three-dimensional shape with respect to a steel material having high hardness, and performs plane cutting of a workpiece. is not.
For this reason, plane cutting of a workpiece having a hard surface layer such as an oxide scale on the surface side of the metal cannot be appropriately performed by the scanning line processing method using the ball end mill shown in Patent Document 1.
Therefore, the present invention has been made in view of this conventional problem, and its purpose is to make a long life without losing the cutting blade, and to perform planar cutting of a workpiece having a hard surface layer on the surface side of the bare metal. A cutting blade, a cutting tool, a cutting blade, and a slab care method using the cutting tool and a slab manufacturing method can be provided.

In order to solve the above-described problem, a cutting blade according to one aspect of the present invention is a cutting blade that performs planar cutting of a workpiece having a hard surface layer on the surface side of the metal, and is directed from the surface layer of the workpiece to the metal. A squeeze surface having a squeeze angle that changes in the cutting depth direction, the squeeze side end of the squeeze surface is positive, and the surface of the surface layer of the workpiece and the main cutting edge of the squeeze surface The gist is that the boundary squeeze angle at the boundary where and intersect is negative.
Further, a cutting tool according to another aspect of the present invention includes the aforementioned cutting blade, a cutter body main body to which the cutting blade is attached, and an arbor to which the cutter body main body is attached, and the arbor is detachably attached to the rotating shaft. The gist is to be attached.

Moreover, the gist of the method for cleaning a slab according to another aspect of the present invention includes a step of plane cutting a part of the metal including the surface layer of the workpiece with the cutting blade of the cutting tool.
Furthermore, the manufacturing method of the slab which concerns on another aspect of this invention makes it a summary to include the process of carrying out plane cutting of a part of ingot including the surface layer of the said workpiece | work with the said cutting blade of the above-mentioned cutting tool.

  According to the cutting blade, the cutting tool, the slab care method, and the slab manufacturing method according to the present invention, the cutting blade has a squeeze angle that changes in a cutting depth direction from the surface layer of the workpiece toward the metal, and a squeeze surface Since the squeeze angle at the end of the bullion side is positive and the squeeze angle at the boundary where the surface of the workpiece surface and the main cutting edge intersect is negative, the cutting blade is missing. Thus, it is possible to provide a cutting blade, a cutting tool, a slab care method, and a slab manufacturing method capable of appropriately performing planar cutting of a workpiece having a long surface and a hard surface layer on the surface side of the metal.

It is a perspective view of a cutting tool provided with a cutting blade concerning a 1st embodiment of the present invention. It is a figure for demonstrating the cutting blade applied to the cutting tool shown in FIG. It is another figure for demonstrating the cutting blade applied to the cutting tool shown in FIG. It is a figure for demonstrating the cutting blade which concerns on a reference example. It is another figure for demonstrating the cutting blade which concerns on a reference example. It is a figure for demonstrating the cutting blade which concerns on 2nd Embodiment of this invention. It is a graph which shows the relationship between the depth from the surface layer (surface) of steel materials, and Vickers hardness. It is a graph which shows the shear stress of the cutting blade when changing a boundary part squeeze angle from -15 degrees-15 degrees.

Next, embodiments of the cutting blade and the cutting tool of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a cutting tool provided with a cutting blade according to the first embodiment of the present invention. The cutting tool 1 has a hard surface layer W2 (FIG. 2) on the surface side of a bare metal W1 (see FIG. 2). It is composed of a face milling tool that performs planar cutting of a workpiece W. The cutting tool 1 includes a plurality of cutting blades 10, a cutter body main body 20 to which the plurality of cutting blades 10 are attached, and an arbor 30 to which the cutter body main body 20 is attached. The cutter body 20 includes a disk-like attachment portion 20 a for attaching a plurality of cutting blades 10, and a shaft portion 20 b attached to the arbor 30. The arbor 30 is detachably attached to a rotating shaft (main shaft) 40 of the machine tool. The plurality of cutting blades 10 are fed at a feed speed Vf in the direction of arrow B while rotating at a peripheral speed Vc in the direction of arrow A together with the arbor 30 and the cutter body main body 20 by rotating the rotating shaft 40 of the machine tool. A part of the bare metal W1 including the surface layer W2 of the workpiece W is subjected to plane cutting.

Here, the workpiece W is a cast slab (steel material), and is carbon steel such as S45C. And the surface layer W2 of the workpiece | work W is an oxidation scale, and as shown in FIG. 7, it has a thickness of about 1.4 mm from the surface, and has a Vickers hardness Hv of about 640.
Further, the base metal W1 has a thickness of 4 mm or more on the back surface side from the boundary between the surface layer W2 and the base metal W1, and has a Vickers hardness of about 250 Hv as shown in FIG. In this way, the surface layer W2 is harder than the base metal W1.
Then, by cutting a part of the metal W1 including the surface layer W2 of the workpiece W with a plurality of cutting blades 10 of the cutting tool 1, the slab is maintained and a slab is manufactured. The manufactured slab is subjected to a subsequent process.

  Here, as shown in FIG. 1, the plurality of cutting blades 10 are attached to the outer peripheral surface of the disc-like attachment portion 2 a of the cutter body main body 20 at equal intervals. 2 and 3, each cutting blade 10 includes a flank 11, a mounting surface 12 extending parallel to the flank 11, a squeeze surface 13 connecting the flank 11 and the mounting surface 12, and a flank. 11 and the attachment surface 12 are connected on the opposite side of the squeeze surface 13, the flank 11, the attachment surface 12, the first end surface 15 that connects the squeeze surface 13 and the connection surface 14, and the flank 11 and the attachment. It is comprised by the square pillar which has the 2nd end surface 16 which connects the surface 12, the squeeze surface 13, and the connection surface 14 on the opposite side to the 1st end surface 15. Each cutting blade 10 is made of high-speed tool steel, carbide or the like. As shown in FIG. 3, each cutting blade 10 has an outer periphery of a disc-shaped mounting portion of the cutter body 20 with a first end surface 15 on the base metal W1 side and a second end surface 16 on the surface layer W2 side and a cutting angle θ. Attached to the surface. The cutting angle θ is preferably 60 ° or less.

  Here, in each cutting blade 10, a corner portion where the flank surface 11 and the squeeze surface 13 intersect is defined as a main cutting blade 17 that cuts the workpiece W. The squeeze surface 13 is formed so that the squeeze angle continuously changes in the cutting depth direction from the surface layer W2 of the workpiece W toward the base metal W1, and as shown in FIG. 2 and FIG. The metal side squeeze angle α1 at the metal side end of the surface 13 (the metal side end 17a of the main cutting edge 17) is positive, and the surface of the surface W2 of the workpiece W of the squeeze surface 13 and the main cutting edge 17 are The boundary squeeze angle α3 at the intersecting boundary part 17c is negative. Further, the surface layer side squeeze angle α2 at the surface layer side end portion of the squeeze surface 13 (surface layer side end portion 17b of the main cutting edge 17) is larger negative than the boundary portion squeeze angle α3.

  In each cutting blade 10, the clearance angle β formed by the flank 11 is constant in the cutting depth direction as shown in FIG. For this reason, the cutting edge angle δ1 at the base metal side end 17a of the main cutting edge 17 is an acute angle smaller than 90 ° because the base metal side squeeze angle α1 is positive. On the other hand, the cutting edge angle δ3 at the boundary portion 17c of the main cutting edge 17 is larger than the cutting edge angle δ1 (the boundary portion squeezing toward the negative side with respect to the clearance angle β) because the boundary portion squeeze angle α3 is negative. If the angle α3 is large, it is an obtuse angle). Further, the cutting edge angle δ2 at the surface layer side end portion 17b of the main cutting edge 17 is larger than the cutting edge angle δ3 because the surface layer side rake angle α2 is more negative than the boundary portion rake angle α3. Yes.

  Here, generally, when the squeeze angle is made negative, the cutting resistance with respect to the workpiece W increases. Since the cutting resistance of the base metal W1 is large, it is desirable that the squeeze angle at which the base metal W1 is cut is positive. On the other hand, in the hard surface layer W2, the cutting resistance is small because the hardness is high but brittle. For this reason, it is possible to make the squeeze angle negative in the surface layer W2. In the surface layer W2, when the squeeze angle is positive, the cutting edge angle becomes an acute angle, so that the shear stress of the cutting edge increases and the cutting edge may be lost. For this reason, in the surface layer W2, it is desirable to prevent the chipping by making the squeeze angle negative and the cutting edge angle obtuse.

  Accordingly, the squeeze surface 13 is formed so that the squeeze angle thereof changes in the cutting depth direction from the surface layer W2 of the workpiece W toward the base metal W1, and the base side of the squeeze surface 13 (the ground of the main cutting edge 17 is formed). Cutting resistance can be suppressed by setting the bullion side squeeze angle α1 at the gold side end portion 17a) to be positive. Further, by making the boundary portion squeeze angle α3 at the boundary portion 17c of the squeeze surface 13 where the surface of the surface layer W2 of the workpiece W intersects the main cutting edge 17 negative, the shear stress of the cutting blade is reduced, and the cutting blade It is possible to appropriately perform planar cutting of a workpiece having a hard surface layer on the surface side of the metal bar with a long life without being lost.

In addition, in order to suppress cutting resistance, the bullion side squeeze angle α1 is preferably greater than 0 ° and 20 ° or less.
Moreover, in order to suppress the shear stress in a cutting blade, it is preferable that boundary part squeeze angle (alpha) 3 is -15 degrees or more and less than 0 degree.
Here, a cutting blade according to a general reference example will be described with reference to FIGS. 4 and 5. 4 and 5, the same members as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and the description thereof may be omitted.

The basic configuration of the cutting blade 10 shown in FIG. 4 and FIG. 5 is the same as that of the cutting blade 10 shown in FIG. 2 and FIG.
That is, in the cutting blade 10 shown in FIGS. 4 and 5, the squeeze angle of the squeeze surface 13 is formed so as to be constant in the cutting depth direction from the surface layer W2 of the workpiece W toward the base metal W1. The squeeze angle α1 of the bullion side at the end portion 13 of the bullion (the end portion 17a of the main cutting edge 17) is positive, and the surface of the surface W2 of the workpiece W and the main cutting edge 17 of the squeeze surface 13 intersect. The boundary squeeze angle α3 at the boundary part 17c is positive and the same as the bullion side squeeze angle α1. The gold side squeeze angle α1 and the boundary squeeze angle α3 are the same and positive.

Further, in each cutting blade 10, the clearance angle β formed by the flank 11 is constant in the cutting depth direction as shown in FIG. For this reason, the cutting edge angle δ1 at the bare metal side end portion 17a of the main cutting edge 17, the cutting edge angle δ3 at the boundary portion 17c of the main cutting edge 17, and the cutting edge angle δ2 at the surface side end portion 17b of the main cutting edge 17 are: These are the same and have an acute angle smaller than 90 °.
In the cutting blade 10 according to this reference example, since the squeeze angle at which the base metal W1 of the workpiece W is cut is positive, the cutting resistance can be suppressed.
On the other hand, since the squeeze angle at which the surface layer W2 is cut is also positive, the cutting edge angle is acute, the shearing stress of the cutting blade is large, and the cutting blade may be lost.
Therefore, as in the cutting blade 10 shown in FIGS. 2 and 3, it is desirable that the surface layer W2 has a negative squeeze angle and an obtuse cutting edge angle to prevent chipping.

(Second Embodiment)
Next, a cutting blade according to a second embodiment of the present invention will be described with reference to FIG.
The cutting blade 100 shown in FIG. 6 is made of high-speed tool steel, carbide or the like, similar to the cutting blade 10 shown in FIGS. 2 and 3, but unlike the cutting blade 10 shown in FIGS. Two squeeze surfaces 113a and 113b are arranged point-symmetrically.
Here, in the cutting blade 100, a corner portion where one flank 111a and one squeeze surface 113a intersect is defined as a main cutting blade 117a that cuts the workpiece W. The squeeze surface 113a is formed such that the squeeze angle continuously changes in the cutting depth direction from the surface layer W2 (see FIG. 2) of the workpiece W to the bare metal W1 (see FIG. 2). The bullion side squeeze angle α1a at the bullion side end of the surface 113a (the bullion side end 117aa of the main cutting edge 117a) is positive, and the surface layer side end of the squeeze surface 113a (surface layer side edge 117ab of the main cutting edge 117a). The surface side squeeze angle α2a in FIG. In addition, the boundary part squeeze angle in the boundary part which the surface of the surface layer W2 of the workpiece | work W and the main cutting edge 117a cross | intersect on the squeeze surface 113a is made negative smaller than the surface layer side squeeze angle (alpha) 2a.

  In each cutting blade 100, the clearance angle βa formed by the clearance surface 11 1a is constant in the cutting depth direction. For this reason, the cutting edge angle at the bare metal side end portion 117aa of the main cutting edge 117a is an acute angle smaller than 90 ° because the bare metal side squeeze angle α1a is positive. On the other hand, the cutting edge angle at the boundary portion of the main cutting edge 117a is larger than the cutting edge angle at the bare metal side end portion 117aa of the main cutting edge 117a because the boundary portion squeeze angle is negative. Further, the cutting edge angle at the surface layer side end portion 117ab of the main cutting edge 117a is larger than the cutting edge angle at the boundary portion of the main cutting edge 117a because the surface layer side rake angle α2a is more negative than the boundary portion squeeze angle. It is a big angle.

  On the other hand, in the cutting blade 100, a corner portion where the other flank 111b and the other squeeze surface 113b intersect is defined as a main cutting blade 117b that cuts the workpiece W. The squeeze surface 113b is formed such that the squeeze angle continuously changes in the cutting depth direction from the surface layer W2 (see FIG. 2) of the workpiece W to the bare metal W1 (see FIG. 2). The bullion side squeeze angle α1b at the bullion side end of the surface 113b (the bullion side end 117ba of the main cutting edge 117b) is positive, and the surface layer side end of the squeeze surface 113b (the surface layer side end 117bb of the main cutting edge 117b). The surface side squeeze angle α2b in FIG. In addition, the boundary part squeeze angle in the boundary part which the surface of the surface layer W2 of the workpiece | work W and the main cutting edge 117b cross | intersect the squeeze surface 113b is made negative smaller than the surface layer side squeeze angle (alpha) 2b.

  In each cutting blade 100, the clearance angle βb formed by the flank 11 1b is constant in the cutting depth direction. For this reason, the cutting edge angle at the bare metal side end portion 117ba of the main cutting edge 117b is an acute angle smaller than 90 ° because the bare metal side squeeze angle α1b is positive. On the other hand, the cutting edge angle at the boundary portion of the main cutting edge 117b is larger than the cutting edge angle at the bare metal side end portion 117ba of the main cutting edge 117b because the boundary portion squeeze angle is negative. Further, the cutting edge angle at the surface layer side end portion 117bb of the main cutting edge 117b is more negative than the cutting edge angle at the boundary portion of the main cutting edge 117b because the surface layer side rake angle α2b is more negative than the boundary portion rake angle. It is a big angle.

  Thus, also in the cutting blade 10 according to the second embodiment, the squeeze surfaces 113a and 113b are formed so that the squeeze angle changes in the cutting depth direction from the surface layer W2 of the workpiece W toward the bare metal W1. Cutting resistance can be suppressed by making the bullion side squeeze angles α1a and α1b positive. In addition, by making the squeeze angle of the boundary portion of the squeeze surface 13 negative, the shear stress of the cutting blade is reduced, the cutting blade is not lost, the life is long, and the workpiece having a hard surface layer on the surface side of the bare metal Planar cutting can be performed appropriately.

Moreover, according to the cutting blade 10 which concerns on 2nd Embodiment, since the two squeeze surfaces 113a and 113b are arrange | positioned point-symmetrically, the cutting blade 10 is rotated and the disk-shaped attachment part 2a of the cutter body main body 20 is provided. It can be attached to the outer peripheral surface of.
In addition, in order to suppress cutting resistance, the metal side squeeze angles α1a and α1b are preferably greater than 0 ° and not greater than 20 °, and more preferably not less than 10 ° and less than 15 °.
Moreover, in order to suppress the shear stress in a cutting edge, it is preferable that it is -15 degrees or more and less than 0 degree, and, as for a boundary part squeeze angle, it is more preferable that it is -10 degrees or more and -5 degrees or less.

As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.
For example, in the cutting blades 10 and 100 according to the first embodiment and the second embodiment, the surface-side squeeze angles α2, α2a, and α2b are negative, but may be positive.
Moreover, in the cutting blade 10 which concerns on 1st Embodiment, although the squeeze surface 13 is formed so that the squeeze angle may change continuously in the cutting depth direction which goes to the metal base W1 from the surface layer W2 of the workpiece | work W. The squeeze angle does not necessarily change continuously. If the bullion side squeeze angle α1 is positive and the boundary squeeze angle α3 is negative, the squeeze angle may be changed stepwise. Good.

In order to verify the effect of the present invention, the cutting tool 1 constituted by the face milling tool shown in FIG. 1 performs plane cutting of the workpiece W having the hard surface layer W2 on the surface side of the bare metal W1, and the boundary at the cutting blade 10 The shear stress at the portion 17c was determined.
Here, the workpiece W as the work material is S45C, and the surface layer W2 has a thickness of about 1.4 mm from the surface and a Vickers hardness Hv of about 640, as shown in FIG. . Further, the base metal W1 has a thickness of 4 mm or more on the back surface side from the boundary between the surface layer W2 and the base metal W1, and has a Vickers hardness of about 250 Hv as shown in FIG.

And the processing conditions by the cutting tool 1 are as follows.
Tool diameter: 70 mm, peripheral speed: 100 m / min, single blade feed: 0.8 mm / blade, cutting depth 5 mm
As the cutting blade 10, the squeeze angle α1 on the bare metal side is + 15 ° in order to suppress cutting resistance, and the cutting is performed when the squeeze angle α3 at the boundary is changed to −15 °, −10 °, 0 °, + 5 °, + 15 °. The shear stress at the boundary of the blade was determined. The clearance angle β of the cutting blade 10 is constant at 5 °. The cutting angle was 45 °. The result is shown in FIG. In FIG. 8, the vertical axis indicating the shear stress of the cutting blade represents the boundary of the cutting blade when the boundary squeeze angle is changed with reference to the shear stress of the boundary of the cutting blade when the boundary squeeze angle is 0 °. The shear stress ratio is shown.

Referring to FIG. 8, it will be understood that the shear stress at the boundary is low and suitable when the boundary squeal angle α3 is not less than −15 ° and less than 0 °.
When the boundary portion squeeze angle α3 is 0 ° or more, the cutting edge angle at the boundary portion becomes an acute angle (the cutting edge angle is 85 ° or less), the shear stress at the boundary portion of the cutting blade increases, and the blade is likely to be lost. On the other hand, when the boundary squeeze angle α3 is larger than −15 ° on the negative side, the cutting edge angle increases and the cross-sectional area at this portion increases, but the cutting resistance increases too much, so that the shear stress increases. Conceivable.

DESCRIPTION OF SYMBOLS 1 Cutting tool 10 Cutting blade 11 Flank 12 Mounting surface 13 Squee surface 14 Connection surface 15 1st end surface 16 2nd end surface 17 Main cutting edge 17a Metal-metal side edge 17b Surface layer side edge 17c Boundary part 100 Cutting blade 111a, 111b Flank 113a, 113b Squee surface 117a, 117b Main cutting edge 117aa, 117ba Ingot end 117ab, 117bb Outer end W Work W1 Ingot W2 Outer surface α1, α1a, α1b Ingot squeeze angle α2, α2a, α2b Surface layer side rake angle α3 Boundary rake angle β, βa, βb Clearance angle δ1, δ2, δ3 Cutting edge angle θ Cutting angle

Claims (7)

A cutting blade that performs planar cutting of a workpiece having a hard surface layer on the surface side of the metal,
It has a squeeze surface having a squeeze angle that changes in the cutting depth direction from the surface layer of the workpiece toward the base metal, and the base metal side squeeze angle at the end of the base metal side of the squeeze surface is positive, A cutting blade having a negative boundary squeeze angle at a boundary portion where the surface of the workpiece surface and the main cutting edge intersect.   2. The cutting blade according to claim 1, wherein the bullion side squeeze angle is greater than 0 ° and 20 ° or less.   The cutting edge according to claim 1 or 2, wherein the boundary portion squeeze angle is -15 ° or more and less than 0 °.   A cutting blade according to any one of claims 1 to 3, a cutter body main body to which the cutting blade is attached, and an arbor to which the cutter body main body is attached, and the arbor is detachably attached to a rotating shaft. A cutting tool characterized by that.   The cutting tool according to claim 4, wherein the cutting tool is configured by a face milling tool, and the cutting blade is attached to the cutter body main body so that a cutting angle with respect to the workpiece is 60 ° or less.   A method for cleaning a slab, comprising the step of plane cutting a portion of a metal bar including a surface layer of the workpiece by the cutting blade of the cutting tool according to claim 4 or 5.   A method for producing a slab comprising a step of plane cutting a part of a metal bar including a surface layer of the workpiece by the cutting blade of the cutting tool according to claim 4 or 5.

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