JP4168697B2 - Sintered plate and tool manufacturing method using the sintered plate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, sintered plate used cemented carbide green compact when sintering, and the sintered plate method of manufacturing a tool used.
[0002]
[Prior art]
Conventionally, a cemented carbide tool is formed by pressing a cemented carbide raw material powder into a mold to form a cemented carbide compact, and then sintering the cemented carbide compact to a location that becomes a blade. Produced after post-processing. The sintering process of the cemented carbide compact is performed in a sintering furnace at about 1400 ° C. in a state where the cemented carbide compact is placed on a sintered plate. In addition, the boring bar, which is a tool used for boring of a shape having an elongated, substantially rod-like shape and having a protruding portion on the side surface, is placed in a state of lying on the sintered plate in the sintering process. On the other hand, the projecting portion is directed in the lateral direction or the upward direction.
[0003]
[Problems to be solved by the invention]
By the way, when the cemented carbide compact is sintered as described above, there is a problem that a chemical reaction occurs between the sintered plate and the cemented carbide compact, resulting in warping of the obtained tool. It was. In particular, an elongated tool such as a boring bar tends to warp because the shrinkage in the length direction differs between the surface in contact with the sintered plate and the other surface.
[0004]
Furthermore, when the projecting portion of the boring bar is directed in the lateral direction or the upward direction and is sintered in contact with the sintered plate, there is a problem that warpage occurs due to the weight of the projecting portion. Although it is possible to make the warped tool into a regular shape by post-processing such as polishing, there is a problem that the post-processing increases the manufacturing cost.
[0005]
The present invention has been made under such a background , and can produce a sintered plate that can suppress warping during sintering of a cemented carbide compact and a tool at low cost. It aims at providing the manufacturing method of the tool using a sintered plate.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention proposes the following means.
The sintered plate of the present invention is used in the sintering process of a cemented carbide tool made of a cemented carbide alloy compact, which is obtained by sintering a cemented carbide compact and is 5 or more times longer than the minimum width. Further, a sintered plate laid and used under the cemented carbide compact, and a protrusion provided on the side surface of the cemented carbide compact which is substantially elongated in the same manner as the tool . A concave portion, a penetrating portion, or a step portion for avoiding interference is provided.
[0007]
The sintered plate according to the present invention avoids interference between the projecting portion provided on the side surface of the cemented carbide compact and the sintered plate by the concave portion, the through portion, or the step portion provided in the sintered plate. Then, the cemented carbide compact is placed on the sintered plate. That is, when a recessed part or a penetration part is formed in the sintered plate, it is possible to avoid the interference by accommodating the protruding part downward in this depression or penetration part and placing the cemented carbide compact. it can. Further, when a step portion is formed on the sintered plate, the cemented carbide compact can be placed so that the protruding portion protrudes from the step portion and faces downward, thereby avoiding interference. Thus, since it can mount and sinter to a sintered board in the state which orient | assigned the protrusion part to the downward direction, the curvature which a tool produces conventionally can be decreased. Thereby, it is possible to obtain a sintered plate that hardly causes warping of the tool during sintering. The cemented carbide in the present invention includes cermet.
[0008]
In addition, the sintered plate of the present invention is formed of graphite, and a mold release agent is disposed in a portion in contact with the cemented carbide compact.
Since the sintered plate according to the present invention is formed by processing graphite, it is stable even at a high temperature. In addition, since the cemented carbide compact is placed on the mold release agent, the chemical reaction between the cemented carbide compact and the sintered plate is further suppressed. Thereby, it is possible to obtain a sintered plate that hardly causes warping of the tool due to a chemical reaction.
[0012]
The method of manufacturing a tool according to the present invention includes a cemented carbide alloy powder compact placed on a sintered plate and sintered, so that the cemented carbide is formed into an elongated substantially rod shape having a length of 5 times or more than the minimum width. A method of manufacturing a cemented carbide tool for manufacturing an alloy tool, wherein a protruding portion is provided on a side surface of the cemented carbide compact in the form of a substantially elongated rod similar to the tool, and The sintered plate is provided with a concave portion, a through portion, or a step portion, and the sintered plate is provided so as to avoid interference between the protruding portion and the sintered plate by the concave portion, the through portion, or the step portion. It has a sintering process in which the cemented carbide alloy compact is placed and sintered.
[0013]
In the method for manufacturing a tool according to the present invention, interference between the protruding portion provided on the side surface of the cemented carbide compact and the sintered plate is avoided by the recessed portion, the penetrating portion, or the stepped portion of the sintered plate. Since the cemented carbide alloy compact has a sintering step in which it is placed on the sintered plate and sintered, warping due to the protruding portion is suppressed. Thereby, the tool made from a cemented carbide with little curvature can be manufactured. Thus, since the tool is sintered in a regular shape, it is not necessary to correct the warp by post-processing such as polishing, and the tool can be manufactured at low cost.
[0014]
In the manufacturing method of the tool according to the present invention, in the above manufacturing method, a convex portion is provided on a side surface provided with the protruding portion, and the convex portion is sintered in a state of being in contact with the sintered plate. And a sintering step.
[0015]
In the manufacturing method of the tool according to the present invention, the interference between the protruding portion and the sintered plate is avoided, and sintering is performed in a state where the convex portion of the cemented carbide alloy compact is in contact with the sintered plate. Since it has a process, the contact area of a cemented carbide compact and a sintered plate decreases, and the curvature by a chemical reaction is suppressed. This makes it possible to manufacture a cemented carbide tool with less warpage.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is an explanatory view of a state during a sintering process in a manufacturing process of a boring bar which is a tool made of cemented carbide. A boring bar is a tool in which a cutting edge is provided at the tip of a protrusion provided on the side surface of an elongated, substantially rod-shaped tip, and a protrusion is provided on the same side as the protrusion. Has a protruding shape. The length of the boring bar is an elongated shape that is five times or more than the minimum width.
[0017]
The cemented carbide powder compact 3 to be sintered and molded into such a tool is compression-molded by press molding a hard raw material powder such as tungsten carbide and a cobalt binder, and has a prescribed shape of the boring bar after sintering. It is formed to become. Accordingly, the cemented carbide powder compact 3 is also provided with a protruding portion 4 on the side surface of the elongated, substantially rod-shaped tip portion like the tool, and the protruding portion 4 protrudes from the protruding portion 6 provided on the same side surface as the protruding portion 4. The shape is made.
[0018]
The sintered plate 1 has a flat plate shape whose upper and lower surfaces are flat, and is formed thicker than the protruding height of the protruding portion 4 of the cemented carbide powder compact 3. The recessed portion 2 provided in the sintered plate 1 has a shape capable of accommodating the protruding portion 4 of the cemented carbide compact 3, and a plurality of recessed portions 2 are provided in one sintered plate 1. The sintered plate 1 is formed of graphite that is stable even at high temperatures, and on its upper surface, for example, a release agent obtained by dissolving carbon powder in an organic solvent is applied or sprayed. The mold release agent is used to suppress a chemical reaction between the sintered plate 1 and the cemented carbide compact 3.
[0019]
In addition, in the sintered plate 5 which is an embodiment provided with the penetrating portion 7 shown in FIG. 2, the protruding portion 4 of the cemented carbide compact 3 can be accommodated in the penetrating portion 7. Also in the sintered plate 10 according to the embodiment provided with the step portion 11 shown in FIG. 3, the cemented carbide powder compact 3 so that the protruding portion 4 protrudes from the step portion 11 and faces downward. Is placed on the stepped portion 11 to avoid interference between the protruding portion 4 and the sintered plate 10. In the following description, the sintered plate 1 shown in FIG. 1 is used, but the sintered plate 5 and the sintered plate 10 are configured to obtain the same operation and effect.
[0020]
The recess 2 is slightly larger than the protrusion 4 and has a circular cross-sectional shape, for example, and one recess 2 is provided for one cemented carbide compact 3. Moreover, the recessed part 2 may be formed in groove shape, and it is good also as a shape which can accommodate the protrusion part 4 of the some cemented carbide alloy compact 3 with respect to the recessed part 2 of the sintered sheet 1 of 1 sheet.
[0021]
The convex portion 6 provided on the cemented carbide compact 3 has a substantially hemispherical shape as shown in FIG. 4 (a). In addition to this shape, the tip as shown in FIG. 4 (b). As shown in FIG. 4 (d), a substantially hemispherical convex portion 6b having a flat surface, a substantially conical convex portion 6c having a curved tip as shown in FIG. 4 (c). A substantially conical convex portion 6d having a flat tip end is used.
[0022]
Further, three or more convex portions 6 are provided, and in FIG. 1, four convex portions 6 are provided in a side view, and at least three of the convex portions 6 are viewed from a direction facing the side surface. By arranging the triangular apexes, it is stably placed on the sintered plate 1. Moreover, the convex part 6 is provided in the position which does not have a trouble in a clamp, when a boring bar is used for a process and it clamps with a holder. Furthermore, when there is a hindrance to the clamp, the convex portion 6 is removed by post-processing such as grinding.
[0023]
The sintering process in the manufacturing process of the boring bar using the sintered plate 1 as described above will be described.
A cemented carbide powder compact 3 in the shape of a boring bar is formed by pressing a cemented carbide raw material powder into a mold and press-molding. The cemented carbide compact 3 is sintered with a mold release agent disposed therein. It is placed on the upper surface of the plate 1. At this time, the protruding portion 4 of the cemented carbide powder compact 3 is accommodated downward in the concave portion 2 provided on the sintered plate 1, and the convex portion 6 is brought into contact with the sintered plate 1. At this time, a space is provided between the inner peripheral surface or bottom surface of the recess 2 and the protrusion 4. A plurality of cemented carbide compacts 3 are placed on one sintered plate 1 and placed in a sintering furnace.
[0024]
The cemented carbide compact 3 is sintered at about 1400 to 1500 ° C. in a state where an inert gas such as N ₂ or Ar is supplied into the sintering furnace. At this time, since the contact surface between the sintered plate 1 and the cemented carbide powder compact 3 is only the tip surface of the convex portion 6, there is little chemical reaction occurring between the sintered plate 1 and the cemented carbide compact 3. The almost entire surface of the cemented carbide powder compact 3 including the protrusion 4 is exposed to an inert gas. In addition, you may sinter in a vacuum state, without using an inert gas.
A blade portion is formed on the protruding portion 4 of the sintered cemented carbide compact 3 to form a boring bar.
[0025]
As described above, the method of manufacturing a boring bar by sintering the cemented carbide green compact 3 using the sintered plate 1 uses the graphite sintered plate 1 provided with a release agent. At the same time, the sintering process is performed with a small contact area between the sintered plate 1 and the cemented carbide powder compact 3 by the convex portion 6 of the cemented carbide compact 3, so the sintered plate 1 and the cemented carbide The chemical reaction with the green compact 3 can be suppressed, and the warp generated in the manufactured boring bar can be reduced.
[0026]
Further, since the protruding portion 4 of the cemented carbide alloy compact 3 is accommodated in the concave portion 2 of the sintered plate 1 and sintered with the protruding portion 4 facing downward, a boring bar with less warpage is manufactured. be able to.
[0027]
Further, in such a tool, the cemented carbide powder compact 3 ′ has a cantilever 8 provided with a step on the surface facing the sintered plate 9 as shown in FIG. When the protruding portion 4 ′ is formed upward at the tip of the portion 8, the height of the convex portion 6 ′ provided in the cantilever portion 8 may be formed higher than the convex portion 6 of the stepped portion. By adopting such a configuration, in the cemented carbide compact 3 ′, the load of the cantilevered portion 8 can be supported by the convex portion 6 ′, so that it can be stably placed on the sintered plate 9. Thus, a boring bar that does not warp due to deflection of its own weight of the cantilever 8 can be manufactured. In this case, the sintered plate 9 does not have to be formed with a recess or a penetration. Further, as shown in FIG. 6, the convex portion 6 ′ is formed so as to have the same height as the step height without providing the convex portion 6, and the convex portion 6 ′ supports the load of the cantilever portion 8. It is good also as a structure. The warp of the cantilever part 8 can also be prevented by forming in this way.
[0028]
In the present embodiment, description has been made using a boring bar as a cemented carbide tool, but the present invention may be used for a cemented carbide tool other than a boring bar. Further, by forming the convex portion 6 in a streak shape, a concave portion surrounded by the convex portion 6 is formed on the side surface of the cemented carbide compact 3, and the surface may be a surface in contact with the sintered plate 1. . Moreover, you may remove a part or all of the convex part 6 in the process process after a sintering process.
[0029]
【The invention's effect】
As described above, according to the sintered plate of the present invention, it is possible to avoid the interference between the protruding portion provided on the side surface of the cemented carbide compact and the sintered plate by the concave portion, the through portion, or the step portion. Therefore, the warp generated in the tool in the sintering process can be suppressed. In addition, the sintered plate is formed by processing graphite and is provided with a release agent. In the sintering process, the sintered plate and the cemented carbide compact are less likely to cause a chemical reaction. The warp that occurs can be suppressed.
[0031]
According to the method of manufacturing a tool of the present invention, the protrusions provided on the side surfaces of the cemented carbide alloy compact and the sintered plate are avoided by the recesses, through portions, or stepped portions of the sintered plate. Since it has the sintering process sintered by the state which orient | assigned the part to the downward direction, the tool which cannot produce a curvature easily can be manufactured. Moreover, the tool which is hard to produce curvature can be manufactured by sintering in the state which the convex part provided in the side surface of the cemented carbide alloy powder contacted the sintered board. This eliminates the need for post-processing such as polishing for correcting the shape after the sintering step, and thus makes it possible to manufacture a cemented carbide tool at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view in a state in which a cemented carbide compact is placed on a sintered plate according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view in a state in which a cemented carbide compact is placed on a sintered plate according to another embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view in a state in which a cemented carbide compact is placed on a sintered plate according to another embodiment of the present invention.
FIG. 4 is a side view of a protrusion provided on the tool and a protrusion having another shape according to an embodiment of the present invention.
FIG. 5 is a schematic cross-sectional view of a tool according to another embodiment of the present invention in a state where a cemented carbide compact is placed on a sintered plate.
FIG. 6 is a schematic cross-sectional view of a tool according to another embodiment of the present invention in a state where a cemented carbide compact is placed on a sintered plate.
[Explanation of symbols]
1, 5, 10 Sintered plate 2 Concave part 3 Cemented carbide compact 4 Protruding part 5 Convex part 6 Through part 11 Step part

Claims (4)

During the sintering process of a cemented carbide tool made of a cemented carbide alloy having a length of 5 times or more than the minimum width obtained by sintering cemented carbide powder compact, A sintered plate that is used under the body,
As in the case of the tool, a concave portion, a penetrating portion, or a step portion for avoiding interference of a protruding portion provided on a side surface of the cemented carbide compact, which is substantially elongated in a rod shape, is provided. Sintered plate. The sintered plate according to claim 1,
A sintered plate characterized by being formed of graphite and having a release agent disposed at a portion in contact with the cemented carbide compact. Carbide for manufacturing a tool made of cemented carbide made of a cemented carbide alloy compact, which is made into a long and slender, almost rod-like shape that is at least 5 times longer than the smallest width by placing the sintered compact on a sintered plate and sintering it. A method of manufacturing an alloy tool,
Similar to the tool, a side surface of the cemented carbide alloy compact, which is substantially elongated, is provided with a protrusion, and the sintered plate is provided with a recess, a penetration, or a step,
Sintering in which the cemented carbide compact is placed on the sintered plate and sintered so as to avoid interference between the projecting portion and the sintered plate by the recessed portion, through portion, or stepped portion. A method for manufacturing a tool, comprising a step. It is a manufacturing method of the tool according to claim 3 ,
Protrusion is provided on the side surface provided with the protrusion, and the sintering includes a sintering process in which the protrusion is sintered in contact with the sintered plate. Method.

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