DE112021006652T5 - Insert and a cutting tool - Google Patents

Abstract

In transmission X-ray diffraction on a cross section of a boron nitride sintered body perpendicular to a first surface (7), an X-ray intensity at a tip of a 111 diffraction peak of cubic boron nitride in the direction perpendicular to the first surface (7) is referred to as IcBN(111)v. The X-ray intensity at the top of a 002 diffraction peak of compressed boron nitride is denoted IhBN(002)v. The X-ray intensity at the top of a 111 diffraction peak of cubic boron nitride in a direction parallel to the first surface 7 is referred to as IcBN(III)h. The X-ray intensity at the top of a 002 diffraction peak of compressed boron nitride is denoted IhBN(002)h. The content value of the compressed boron nitride determined from these X-ray intensities is greater than 0.002 and less than 0.01. The cubic orientation value is greater than 0.5, and the orientation value of the compressed boron nitride is greater than the cubic orientation value. The Vickers hardness in a direction perpendicular to the first surface of the boron nitride sintered body is 40.0 GPa or more at 1000°C.

Description

TECHNICAL FIELD

The present disclosure relates to an insert and a cutting tool.

BACKGROUND OF THE INVENTION

A boron nitride sintered body has a high hardness. The boron nitride sintered body is used, for example, in inserts for shredding elements and tools, taking advantage of its properties.

Patent Document 1 describes a boron nitride sintered body containing cubic boron nitride. Patent Document 1 also describes a polycrystalline cubic boron nitride composite containing wurtzite-type boron nitride and having an orientation plane in which the ratio I ₍₂₂₀₎ / I ₍₁₁₁₎ of an X-ray diffraction intensity I ₍₂₂₀₎ of a (220) plane of the cubic Boron nitride to an X-ray diffraction intensity I ₍₁₁₁₎ of a (111) plane of cubic boron nitride is less than 0.1. In other words, in the orientation plane of the polycrystalline cubic boron nitride composite, the I ₍₁₁₁₎ is 10 times or more as large as the I ₍₂₂₀₎ . That is, one can say that the (111) plane is strongly oriented in the orientation plane. The polycrystalline cubic boron nitride composite is obtained by using oriented pBN as raw material. It is found that when taking hexagonal boron nitride as a comparative example, the wear is large and the performance as a cutting tool is poor even if the (111) plane is strongly oriented in the orientation plane of the cubic boron nitride.

QUOTE LIST

PATENT LITERATURE

Patent document 1: JP 5929655B

BRIEF EXPLANATION

An insert according to an aspect of the present disclosure includes a boron nitride sintered body having a first surface, a second surface, and a cutting edge disposed on at least a portion of a crest portion of the first surface and the second surface. The boron nitride sintered body contains cubic boron nitride and compressed boron nitride. In a transmission Diffraction peaks of the compressed boron nitride are referred to as IhBN(002)v, and in a direction parallel to the first surface, an X-ray intensity at a peak of a 111 diffraction peak of the cubic boron nitride is referred to as IcBN(111)h, and an X-ray intensity at a peak of a 002 Diffraction peaks of compressed boron nitride denoted as IhBN(002)h. A content value of the compressed boron nitride, indicated by (IhBN(002)v + IhBN(002)h)/(IcBN(111)v + IcBN(111)h), is greater than 0.002 and less than 0.01. A cubic orientation value, given by IcBN(111)v/(IcBN(111)v + IcBN(111)h), is greater than 0.5. An orientation value of the compressed boron nitride, indicated by IhBN(002)v/(IhBNv(002) + IhBN(002)h), is larger than the cubic orientation value. The Vickers hardness in a direction perpendicular to the first surface of the boron nitride sintered body is 40.0 GPa or more at 1000°C.

A cutting tool according to an aspect of the present disclosure includes a holder having a length extending from a first end to a second end and a pocket on the side of the first end, and the insert is located in the pocket.

BRIEF DESCRIPTION OF THE DRAWINGS

• 1 is a perspective view showing an example of use in accordance with the present disclosure.
• 2 is a perspective view showing another example of use in accordance with the present disclosure.
• 3 shows an example of a cutting tool of the present disclosure.
• 4 is a diagram showing results of a high temperature hardness measurement.

DESCRIPTION OF EMBODIMENTS

The following is a detailed description of an insert and a cutting tool according to the present disclosure (hereinafter referred to as “embodiments”) with reference to the drawings. The present disclosure is not limited to the embodiments. Furthermore, the embodiments can be combined appropriately so that they do not contradict each other in terms of processing content. In the following embodiments, like portions are denoted by like reference numerals, and overlapping explanations are omitted.

In the embodiments described below, terms such as “constant,” “orthogonal,” “perpendicular,” and “parallel” may be used, but these terms need not exactly mean “constant,” “orthogonal,” “perpendicular,” and “parallel.” In other words, each of the expressions described above allows for variations in, for example, manufacturing accuracy, positioning accuracy, and the like.

To simplify the description, the corresponding drawings referred to below show in a simplified form only the necessary main parts.

An insert made of a boron nitride sintered body is known. The use of this type can still be improved in terms of increasing wear resistance.

Mission

1 shows an example of an insert 1 according to the present disclosure. In the in 1 In the example shown, the insert 1 is a boron nitride sintered body 3 with a polygonal shape. 2 shows another example of an insert 1 according to the present disclosure. 2 shows an example in which the boron nitride sintered body 3 is connected to a base body 5, for example made of hard metal. The base body 5 and the boron nitride sintered body 3 are bonded together to form the insert having the polygonal shape. This arrangement makes it possible to reduce the proportion of the relatively expensive boron nitride sintered body 3 in use 1. In the in 2 In the example shown, the boron nitride sintered body 3 is located on one of the plurality of corner parts of the insert 1. The boron nitride sintered body 3 may also be arranged on two or more of the plurality of corner parts of the insert 1, but is not limited to this.

For example, a connecting material containing Ti or Ag (not shown) can be arranged between the boron nitride sintered body 3 and the base body 5. The boron nitride sintered body 3 and the base body 5 can be joined together with the connecting material arranged therebetween by a conventionally known joining method.

The boron nitride sintered body 3 has a first surface 7 and a second surface 9. In the in the 1 and 2 In the examples shown, the first surface 7 is an upper surface of the insert 1 and the second surface is a side surface of the insert 1. Furthermore, in the 1 and 2 In the examples shown, the first surface 7 becomes a rake surface and the second surface 9 becomes an open surface. Below, the first surface 7 can be referred to as a rake surface 7. The second area 9 can be referred to as an open area 9. The insert 1 has a cutting edge 13 on at least a part of a comb part of the first surface 7 and the second surface 9.

The boron nitride sintered body 3 in insert 1 of the present disclosure contains cubic boron nitride and compressed boron nitride.

Among data obtained in a transmission X-ray diffraction of a cross section of the boron nitride sintered body 3 perpendicular to the first surface 7, the X-ray intensity of the 111 diffraction of the cubic boron nitride in a direction perpendicular to the first surface 7 is referred to as IcBN(111)v. The X-ray intensity of the 002 diffraction of the compressed boron nitride in the direction perpendicular to the first surface 7 is referred to as IhBN(002)v. The X-ray intensity of the 111 diffraction of the cubic boron nitride in a direction parallel to the first surface 7 is referred to as IcBN(III)h, the data coming from the transmission X-ray diffraction of the cross section of the boron nitride sintered body 3 perpendicular to the first surface 7. The X-ray intensity of the 002 diffraction of the compressed boron nitride in the direction parallel to the first surface 7 is referred to as IhBN(002)h.

It should be noted that the respective levels in the cubic boron nitride described above are indicated based on JCPDS card No. 01-075-6381. The corresponding levels in compressed boron nitride are specified based on JCPDS Chart No. 18-251. The corresponding planes in hexagonal boron nitride are specified based on JCPDS card No. 00-045-0893. The corresponding levels in the wurtzite-type boron nitride described later are specified based on JCPDS card No. 00-049-1327.

Transmission X-ray diffractometry can be carried out, for example, with a curved IPX X-ray diffractometer “RINT RAPID2” available from Rigaku Corporation.

The ratio (IhBN(002)v + IhBN(002)h)/(I(111)v + IcBN(111)h), which is determined based on the individual X-ray intensities, is called the content value of the compressed boron nitride. The compressed boron nitride content value is an index related to the amount of compressed boron nitride that the boron nitride sintered body 3 has. The larger this value, the more compressed boron nitride is present in the boron nitride sintered body 3. The content value of compressed boron nitride is not the content itself.

In the boron nitride sintered body 3 in the insert 1 of the present disclosure, the compressed boron nitride content value is greater than 0.002 and less than 0.01. That is, the boron nitride sintered body 3 in the insert 1 of the present disclosure contains the compressed boron nitride to the extent that this condition is satisfied. IcBN(111)v/(IcBN(111)v + IcBN(111)h) obtained based on each of the X-ray intensities is called a cubic orientation value. When the cubic orientation value is 0.5, a 111 plane of cubic boron nitride is oriented in a random direction and is in an unoriented state. The larger the cubic orientation value, the more the 111 plane of the cubic boron nitride that the boron nitride sintered body 3 has is oriented parallel to the first surface 7.

In the boron nitride sintered body 3 in the insert 1 of the present disclosure, the cubic orientation value is larger than 0.5. In other words, the X-ray intensity at the top of a 111 diffraction peak of cubic boron nitride in a perpendicular direction is larger than the X-ray intensity at the top of a 111 diffraction peak of cubic boron nitride in a parallel direction. That is, one can also say that the 111 plane of the cubic boron nitride is oriented along a normal direction of the first surface 7.

IhBN(002)v/(IhBN(002)v + IhBN(002)h) obtained based on each of the X-ray intensities is called the orientation value of the compressed boron nitride. When the orientation value of the compressed boron nitride is 0.5, the 002 plane of the compressed boron nitride is oriented in a random direction and is in an unoriented state. The larger the orientation value of the compressed boron nitride, the more the 002 plane of the compressed boron nitride that the boron nitride sintered body 3 has is oriented parallel to the first surface 7.

In the boron nitride sintered body 3 in the insert 1 of the present disclosure, the orientation value of the compressed boron nitride is larger than the cubic orientation value. That is, the 002 plane of the compressed boron nitride is oriented more parallel to the first surface 7 than the 111 plane of the cubic boron nitride.

The insert 1 of the present disclosure has excellent wear resistance due to the above configuration. This effect appears to be due to the fact that the insert 1 of the present disclosure contains a small amount of compressed boron nitride, the 002 plane of the compressed boron nitride is more aligned in the first surface, and therefore a workpiece welded to the first surface is peeled off together with the compressed boron nitride.

The boron nitride sintered body 3 in the insert 1 of the present disclosure may have a compressed boron nitride content value of 0.004 or more and 0.008 or less. This configuration results in a high hardness of the insert 1.

The boron nitride sintered body 3 in the insert 1 of the present disclosure may have a cubic orientation value of 0.55 or more. This configuration leads to a high hardness of the first surface 7.

Furthermore, the boron nitride sintered body 3 in the insert 1 of the present disclosure may have a compressed boron nitride orientation value of 0.8 or more. This configuration results in a long service life for insert 1.

Furthermore, the boron nitride sintered body 3 in the insert 1 of the present disclosure may contain wurtzite-type boron nitride. The boron nitride sintered body 3 having this configuration has high hardness.

An average particle diameter of the cubic boron nitride in the insert 1 of the present disclosure may be 200 nm or less. This configuration results in high strength of the insert 1. Note that the average particle diameter of the cubic boron nitride may be 100 nm or less.

The insert 1 of the present disclosure may have a hard layer (not shown) on a surface of the boron nitride sintered body 3.

Vickers hardness

In use 1 of the present disclosure, the Vickers hardness in a direction perpendicular to the first surface 7 of the boron nitride sintered body 3 at 1000°C is 40.0 GPa or more.

The Vickers hardness in the direction perpendicular to the first surface 7 of the boron nitride sintered body 3 is greater than 45.0 GPa at 700 ° C.

The Vickers hardness in the direction perpendicular to the first surface 7 of the boron nitride sintered body 3 is greater than 47.0 GPa at 400 ° C.

As described above, the insert 1 of the present disclosure has high hardness at high temperatures and therefore has excellent wear resistance in high-temperature cutting.

cutting tool

The cutting tool of the present disclosure is described with reference to 3 described. 3 is a view showing an example of the cutting tool of the present disclosure.

As in 3 For example, as shown, a cutting tool 101 of the present disclosure is a body having a rod shape and extending from a first end (upper end in 3 ) to a second end (lower end in 3 ) extends.

As in 3 As shown, the cutting tool 101 has a holder 105 whose length extends from the first end (front end) to the second end and which has a pocket 103 disposed on the side of the first end, and the insert 1 is located in the Pocket 103. Since the cutting tool 101 has the insert 1, continuous machining can be carried out for a long period of time.

The pocket 103 is a part in which the insert 1 is mounted, and has a seat surface that is parallel to a lower surface of the holder 105 and has a restriction side surface that is perpendicular or oblique to the seat surface. The pocket 103 is open at the first end side of the holder 105.

The insert 1 is positioned in the pocket 103. At this time, the lower surface of the insert 1 may be in direct contact with the pocket 103, or a plate (not shown) may be disposed between the insert 1 and the pocket 103.

The insert 1 is attached to the holder 105 in such a way that at least a part of a section that can be used as a cutting edge 13 protrudes outwards from the holder 105 on a comb part on which the cutting surface 7 and the open surface 9 intersect. In the present embodiment, the insert 1 is attached to the holder 105 with a fastening screw 107. That is, the insert 1 is fixed to the holder 105 by inserting the fixing screw 107 into a through hole 55 of the insert 1, inserting a front end of the fixing screw 107 into a screw hole (not shown) defined in the pocket 103, and the portions with Threads are screwed together.

As a material for the holder 105, steel or cast iron can be used. Among these materials, steel with high toughness can be used.

In the present embodiment, a cutting tool for a so-called turning operation is used as an example. Examples of turning machining may include inner diameter machining, outer diameter machining, and grooving machining. It should be noted that a cutting tool is not limited to those used in turning machining. For example, the insert 1 according to the embodiment described above can be used as a cutting tool for milling.

Manufacturing process

An example of a method for producing a boron nitride sintered body using the present disclosure will be described below. First, hexagonal boron nitride powder is produced, which serves as raw material and has a flat shape. One of the commercially available raw materials whose average particle diameter is 0.7 μm or larger and whose oxygen impurity content is less than 0.5 mass percent is used. The average particle diameter of the hexagonal boron nitride powder refers to an average value of the lengths in the longitudinal axis direction of the boron nitride powder measured with an electron microscope. The hexagonal boron nitride powder may have an average particle diameter of 0.2 µm or more and 30 µm or less. The hexagonal boron nitride powder can have a high purity of 99% or more. The hexagonal boron nitride powder may contain a catalyst component used in the production of cubic boron nitride powder. Alternatively, a raw material powder with a purity of less than 99% can also be used.

A cubic orientation value and an orientation value of the compressed boron nitride after sintering can be controlled by molding the raw material powder by uniaxial pressing and by controlling the pressure during molding. The flat hexagonal boron nitride powder is oriented during molding by uniaxial pressing so that the 002 plane of the hexagonal boron nitride powder is oriented perpendicular to the pressing axis direction of pressing. When the uniaxial pressing is carried out so that the same powder compact is subjected to repeated pressure, the orientation of the hexagonal boron nitride powder in the powder compact is high.

Subsequently, the boron nitride sintered body of the present disclosure can be obtained by firing the powder compact prepared by the above method at a temperature of 1800 to 2200 degrees and a pressure of 8 to 10GPa. The proportion of compressed boron nitride contained in the boron nitride sintered body can be controlled by the temperature and pressure during firing.

While the boron nitride sintered body, insert and cutting tool of the present disclosure have been described, the present disclosure is not limited to the above embodiment, and various improvements and changes can be made without departing from the spirit of the present disclosure.

Example

Powder compacts were obtained by uniaxial pressing of flat-shaped hexagonal boron nitride powders with average particle diameters of 0.3 μm, 6 μm and 16 μm and an oxygen impurity content of 0.3 mass%. The same hexagonal boron nitride powders were uniformly pressed into powder compacts. These powder compacts were fired under the conditions shown in Table 1.

Subsequently, the obtained sintered bodies were cut in a direction perpendicular to the first surface of the sintered bodies, thereby producing test specimens each having a surface intersecting the first surface at right angles and having a thickness of about 0.5 mm. Using the curved IP X-ray diffractometer “RINT RAPID2” available from Rigaku Corporation, the compressed boron nitride content value, the cubic orientation value and the compressed boron nitride orientation value were determined based on a cross section perpendicular to the first surface of the test specimens. The values determined are listed in Table 1. [Table 1] Sample no. Particle diameter (µm) of the hexagonal boron nitride powder printing molding process Firing temperature (°C) Pressure (GPa) Compressed boron nitride content value Cubic orientation value Orientation value of the compressed boron nitride 1 0.3 Uniform pressure 2100 9 0.0038 0.49 0.50 2 6 Uniform pressure 2100 9 0.0040 0.51 0.49 3 16 Uniform pressure 2100 9 0.0043 0.52 0.51 4 0.3 uniaxial 2100 9 0.0037 0.54 0.56 5 6 uniaxial 2100 9 0.0041 0.56 0.61 6 16 uniaxial 2100 9 0.0043 0.58 0.68 7 6 Uniform pressure 2100 11 0.0000 0.50 - 8th 0.3 uniaxial 2100 11 0.0000 0.55 - 9 6 uniaxial 2100 11 0.0000 0.56 - 10 16 uniaxial 2100 11 0.0000 0.59 - 11 6 Uniform pressure 1700 11 0.0040 0.51 0.46 12 0.3 uniaxial 1700 11 0.0036 0.60 0.64 13 6 uniaxial 1700 11 0.0035 0.64 0.80 14 16 uniaxial 1700 11 0.0038 0.70 1.00 15 16 Uniform pressure 2300 7.7 0.0040 0.51 0.49 16 16 uniaxial 2300 7.7 0.0040 0.54 0.51

A piece was cut from each of the obtained sintered bodies to make an insert. A cutting test was carried out using the first surface of the insert as the rake face. The conditions for the cutting test are set out below.

Conditions for the cutting test

• Workpiece material: Ti alloy (Ti-6Al - 4V)
• Cutting conditions: Vc = 100 m/min, f = 0.1 mm/rev, ap = 0.4 mm, wet
• Tool used: CNGA120408

Samples Nos. 1-3, 7, 11 and 15, which are the samples obtained from the powder compacts formed under uniform pressure, do not have the configuration of the boron nitride sintered body in the application of the present disclosure. Even when a powder compact made by uniaxial pressing was used, Samples Nos. 8 to 10, which were made with a firing temperature of 2100°C and a firing pressure of 11 GPa, did not contain compressed boron nitride. Sample No. 16, which was prepared using a powder compact obtained by uniaxial pressing, a firing temperature of 2300 ° C and a firing pressure of 7.7 GPa, contained compressed boron nitride, but the orientation value of the compressed boron nitride was smaller than the cubic orientation value.

On the other hand, Sample Nos. 4 to 6 and 12 to 14 of the samples formed by uniaxial pressing had compressed boron nitride content values of less than 0.005, cubic orientation values of more than 0.5, and compressed boron nitride orientation values of more than the cubic orientation values, and thus a long lifetime. Note that the average particle diameters of the cubic boron nitrides of samples Nos. 4 to 6 and 12 to 14 were all 200 nm or smaller. Specifically, the average particle diameter of Sample No. 4 and Sample No. 12 using a raw material powder having a small average particle diameter was 100 nm or less each.

Samples No. 5, 6, 12, 13 and 14, all of which had a cubic orientation value of 0.55 or more, had a longer life than sample No. 4 with a cubic orientation value of less than 0.55. Samples No. 13 and 14, each having a compressed boron nitride orientation value of 0.8 or more, had a longer life than Sample No. 12 having a compressed boron nitride orientation value of less than 0.8.

Samples that do not meet the configuration requirements of the use of the present disclosure had a shorter lifespan than Sample Nos. 4 to 6 and 12 to 14, all of which are the use of the present disclosure.

Measuring high temperature hardness

Powder compacts were prepared by uniaxial pressing of flat-shaped hexagonal boron nitride powders with average particle diameters of 0.3 μm, 6 μm, and 16 μm and an oxygen impurity content of 0.3 mass%. The powder compact was fired at a firing temperature of 2100 to 2200 ° C and 9 GPa.

Subsequently, the Vickers hardness of the obtained sintered body was measured at temperature environments of 25°C, 400°C, 700°C and 1000°C, respectively. The Vickers hardness was determined using a known test method in which a pyramid-shaped (square) diamond indenter was pressed into the first surface (rake face) of the sintered body and the indentation remaining after the load was removed was measured. The measurement conditions are as follows.

Measurement conditions

• Gauge: QM Type High Temperature Hardness Gauge available from Nikon Corporation
• Penetration force of the indenter: 4.9 N
• Duration of penetration of the indenter: 15 s
• Measuring atmosphere: vacuum

4 is a diagram showing a result of high temperature hardness measurement. As in 4 As shown, the Vickers hardness in the direction perpendicular to the first surface of the obtained sintered body was about 42.0 GPa at 1000°C, about 46.0 GPa at 700°C and about 48.0 GPa at 400°C.

It should be noted that the embodiments disclosed herein are in all respects exemplary and not limiting. The embodiments described above can be implemented in a variety of ways. The embodiments described above may be omitted, substituted or modified in various ways without departing from the scope and spirit of the appended claims.

REFERENCE MARKS

1

Mission

3

Boron nitride sintered body

5

Basic body

7

rake face

9

open space

13

cutting edge

101

cutting tool

103

Bag

105

holder

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 5929655 B [0004]

Claims (8)

An insert comprising: a boron nitride sintered body having a first surface, a second surface and a cutting edge disposed on at least a portion of a ridge portion of the first surface and the second surface, wherein the boron nitride sintered body contains cubic boron nitride and compressed boron nitride, where in a transmission X-ray diffraction of a cross section of the boron nitride sintered body perpendicular to the first surface, when, in a direction perpendicular to the first surface, an X-ray intensity at a tip of a 111 diffraction peak of the cubic boron nitride is denoted as IcBN(111)v and an X-ray intensity at a tip of a 002 diffraction peak of the compressed boron nitride is denoted as IhBN(002)v, and in a direction parallel to the first surface, an X-ray intensity at a tip of a 111 diffraction peak of the cubic boron nitride is denoted as IcBN(III)h and an X-ray intensity at a tip of a 002 diffraction peak of the compressed boron nitride is denoted as IhBN(002)h, a content value of the compressed boron nitride, indicated by (IhBN(002)v + IhBN(002)h)/(IcBN(111)v + IcBN(111)h), is greater than 0.002 and less than 0.01, a cubic orientation value, given by IcBN(111)v/(IcBN(111)v + IcBN(111)h), is greater than 0.5 and an orientation value of the compressed boron nitride, indicated by IhBN(002)v/(IhBN(002)v + IhBN(002)h), is larger than the cubic orientation value; and where the Vickers hardness in a direction perpendicular to the first surface of the boron nitride sintered body at 1000°C is 40.0 GPa or more. The use according to Claim 1 , where the cubic orientation value is 0.55 or greater. The use according to Claim 1 or 2 , wherein the orientation value of the compressed boron nitride is 0.8 or greater. The use according to one of the Claims 1 until 3 , wherein the boron nitride sintered body contains wurtzite-type boron nitride. The use according to one of the Claims 1 until 4 , wherein an average particle diameter of the cubic boron nitride in cross section is 200 nm or smaller. The use according to one of the Claims 1 until 5 , where the Vickers hardness is greater than 45.0 GPa at 700 ° C. The use according to one of the Claims 1 until 6 , where the Vickers hardness at 400 ° C is greater than 47.0 GPa. A cutting tool comprising: a holder having a length extending from a first end to a second end and having a pocket on the side of the first end; and the use according to one of the Claims 1 until 7 , which is arranged in the bag.

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