JP2010089184A - Surface coated cutting tool base material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool base material having excellent oxidation resistance, heat resistance and abrasion resistance, and capable of stably executing the dry machining of steel and high-speed machining of high-strength material for a long time by improving a coating film formed on a surface of the surface coated cutting tool base material. <P>SOLUTION: An Al-Cr-N coating film with a crystalline structure thereof being a NaCl type structure and expressed by general formula for the (Al<SB>x</SB>, Cr<SB>1-x</SB>)N (where x satisfies the condition of 0.55≤x≤0.75), and an Al-Cr-Ti-N coating film with a crystalline structure thereof being a NaCl type structure and expressed by general formula for the (Al<SB>y</SB>, Cr<SB>1-y-z</SB>, Ti<SB>z</SB>)N (where y and z satisfy the conditions of 0.55≤y≤0.75, 0.2≤z≤0.3, 0.05≤1-y-z≤0.2) are alternately layered on a surface of a surface coated cutting tool base material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coated cutting tool substrate in which a coating is formed on the surface of a cutting tool substrate made of cemented carbide or cermet, etc., and improves the coating formed on the surface of the cutting tool substrate to improve oxidation resistance. It is excellent in heat resistance, heat resistance and wear resistance, and is characterized in that dry cutting of steel materials and high-speed cutting of hard materials can be performed stably over a long period of time.

  Conventionally, in order to improve the wear resistance and the like of a cutting tool made of cemented carbide or cermet, the surface of such a cutting tool base material is coated with a film made of TiN, TiCN, TiAlN or the like. Things have been done.

  However, in recent years, in order to increase the processing efficiency of high-hardness materials, high-hardness materials are cut at high speed, or steel materials and the like are dry-cutting instead of wet processing from the environmental viewpoint. As the temperature of the cutting edge of the cutting tool becomes high and the load applied to the cutting edge becomes large, the surface of the cutting tool base material is coated with a film made of TiN, TiCN, TiAlN, or the like as described above. When a cutting tool is used, there has been a problem in that these cutting processes cannot be stably performed over a long period of time.

  For this reason, conventionally, Ti, Al, Cr, C, and N are predetermined on the surface of the cutting tool base material, as shown in Patent Document 1, as a film having superior wear resistance characteristics and the like than the TiAlN film. As shown in Patent Document 2, the surface of the cutting tool base material is made of Ti, Al, Si, C, and N with predetermined atoms. The surface of the cutting tool base material is coated with a TiAlSiCN film in the ratio range, and a nitride layer mainly composed of Ti and Si, Cr, Nb as shown in Patent Document 3. Or a film made of a nitride film containing at least one selected from Ti and Ti at a predetermined ratio and a film film made of nitride containing Ti and Al at a predetermined ratio, Al and Cr are What provided the AlCrN membrane | film | coat which became the range of ratio is disclosed.

  However, in the case where the film shown in Patent Documents 1 and 3 is formed, there is a problem that Ti in the film is oxidized at a high temperature and the film is easily worn. In the film, there is a problem that Si in the film increases the affinity with the steel material and wear increases when the steel material is cut. In the case of the AlCrN film shown in Patent Document 4, the hardness is low. When used in a cutting tool, there is a problem that wear increases.

  Further, in recent years, as shown in Patent Document 5, a film made of nitride or the like containing Al and at least one selected from Cr and V in a predetermined ratio, and a film made of Ti carbonitride A laminate of these is disclosed.

Here, when cutting a hard material at high speed, the rake face of the cutting edge is in contact with the chips, so a chemically stable and highly heat-resistant film is required even at high temperatures, while the flank face In this case, since the film is in direct contact with the work material at the time of cutting, a film with higher wear resistance is required, and both characteristics of heat resistance and wear resistance are required. Even in the case where such films are laminated, it has been difficult to sufficiently improve both the heat resistance and wear resistance characteristics.
JP 2003-71610 A JP-A-8-209336 JP 2000-326106 A Japanese Patent Laid-Open No. 10-25566 JP 2005-262386 A

  An object of the present invention is to solve the above-described problems in a coated cutting tool base material in which a film is formed on the surface of a cutting tool base material made of cemented carbide, cermet, or the like. The problem is to improve the coating formed on the surface of the tool base, and to have excellent oxidation resistance, heat resistance and wear resistance, and to enable stable long-term dry cutting of steel materials and high-speed cutting of hard materials. It is what.

In the coated cutting tool base material according to the present invention, in order to solve the above-described problems, a general formula (Al _x , Cr _1-x ) N (wherein the crystal structure is an NaCl type structure is formed on the surface of the cutting tool base material. In the formula, x is an Al—Cr—N film represented by 0.55 ≦ x ≦ 0.75, and a general formula (Al _y , Cr _1-y whose crystal structure is an NaCl type structure). _-z, during Ti _z) N (wherein, y, z is the 0.55 ≦ y ≦ 0.75,0.2 ≦ z ≦ 0.3,0.05 ≦ 1-y-z ≦ 0.2 Al—Cr—Ti—N films represented by the above conditions are alternately laminated.

  Here, in the Al—Cr—N film and the Al—Cr—Ti—N film, the atomic ratios x and y of Al are 0.55 ≦ x ≦ 0.75 and 0.55 ≦ y ≦ 0.75. When the atomic ratio x, y of Al is less than 0.55, the hardness of these films is lowered and the oxidation resistance is deteriorated. This is because the film has a hexagonal crystal structure instead of the NaCl type, and the hardness of these films decreases.

  In the Al-Cr-Ti-N coating, the Ti atomic ratio z satisfies the condition of 0.2 ≦ z ≦ 0.3 because the Ti atomic ratio z is less than 0.2. This is because the hardness of the film is lowered and the wear resistance is deteriorated, whereas when it exceeds 0.3, the oxidation resistance and heat resistance of the film are lowered. Also, the Cr atomic ratio 1-yz satisfies the condition of 0.05 ≦ 1-yz ≦ 0.2 because the Cr atomic ratio 1-yz is less than 0.05. In this case, the oxidation resistance of the film is lowered, whereas if it exceeds 0.2, the hardness of the film is lowered and the wear resistance is deteriorated.

  Here, the above Al—Cr—N film is particularly excellent in oxidation resistance and heat resistance, while the above Al—Cr—Ti—N film is particularly excellent in wear resistance, and these films are the same crystal. Because of the NaCl-type structure, when these films are alternately laminated, the consistency between the films is high and the adhesion is excellent, and the above-mentioned characteristics of each film are combined to produce a synergistic effect. As a result, a film excellent in oxidation resistance, heat resistance and wear resistance is formed on the surface of the cutting tool base material.

  Here, the above-described Al—Cr—N coating generally has an (111) plane X-ray diffraction intensity I (111) and an (200) plane X-ray diffraction intensity I (200) of I (111)> I. The above-mentioned Al—Cr—Ti—N film satisfies the relationship of (200), and generally, the (111) plane X-ray diffraction intensity I (111) and the (200) plane X-ray diffraction intensity I (200) Satisfies the relationship of I (111) <I (200). Then, the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction intensity I (200) of the (200) plane in the entire film laminated as described above are I (111)> I ( If the relationship 200) is satisfied, the above-described characteristics of the laminated film are further improved, although the reason is not clear.

  In addition, when alternately laminating the Al-Cr-N coating and the Al-Cr-Ti-N coating on the surface of the cutting tool base made of cemented carbide or cermet, the cutting tool base After forming the Al—Cr—Ti—N film on the surface, the Al—Cr—N film and the Al—Cr—Ti—N film are alternately laminated, and the film in contact with the surface of the cutting tool base material is made of Al— When composed of a Cr-Ti-N coating, the adhesion between the surface of the cutting tool substrate and these coatings is enhanced, and the coating is further prevented from peeling off from the surface of the cutting tool substrate. Become.

  In addition, when the Al-Cr-N coating and the Al-Cr-Ti-N coating were alternately laminated on the surface of the cutting tool base as described above, the oxidation resistance and heat resistance were excellent. When the Al—Cr—N film is positioned on the outermost surface, sufficient heat resistance can be obtained even when the temperature of the cutting edge of the cutting tool becomes high, as in the case of cutting a high hardness material at high speed. .

  In addition, when alternately laminating the Al—Cr—N film and the Al—Cr—Ti—N film on the surface of the cutting tool base as described above, the respective films are sequentially formed by various physical vapor deposition methods. However, in order to improve the adhesion between the cutting tool base material and the film and the adhesion between the films, it is preferable to use an arc ion plating method using arc discharge.

In the coated cutting tool base material according to the present invention, the general formula (Al _x , Cr _1-x ) N (wherein x is 0.55 ≦≦ C) is a NaCl type crystal structure on the surface of the cutting tool base material. satisfies the condition x ≦ 0.75. and Al-Cr-N film represented by), the crystal structure is NaCl-type structure formula _{(Al y, Cr 1-y} -z, Ti z) N ( wherein , Y and z satisfy the conditions of 0.55 ≦ y ≦ 0.75, 0.2 ≦ z ≦ 0.3, and 0.05 ≦ 1-yz ≦ 0.2). Since the Cr-Ti-N coatings are alternately laminated, the properties and wear resistance of the Al-Cr-N coatings, which are highly compatible with each other and have excellent adhesion, as well as excellent oxidation resistance and heat resistance. Combined with the characteristics of the Al-Cr-Ti-N coating with excellent properties, it exhibits a synergistic effect. On the surface of the cutting tool base, oxidation resistance, So film excellent heat and wear resistance is formed.

  As a result, in the coated cutting tool base material according to the present invention, the oxidation film, the heat resistance, and the wear resistance are greatly improved by the respective films laminated on the surface of the cutting tool base material as described above, and the dry cutting of the steel material is performed. In addition, high-speed cutting of high hardness materials can be performed stably over a long period of time.

  Next, the coated cutting tool base material according to the present invention will be specifically described with reference to examples, and in the cutting tool using the coated cutting tool base material according to this example, dry cutting and high cutting of steel materials are performed. A comparative example will clarify that high-speed cutting of a hard material can be performed stably over a long period of time. The coated cutting tool substrate according to the present invention is not particularly limited to those shown in the following examples, and can be implemented with appropriate modifications within a range not changing the gist thereof.

  Here, in each example and each comparative example, as a cutting tool base material for forming a film, a solid-type ball end mill having an outer diameter of 10 mm, a length and a width of 12.7 mm, and a thickness of 4.76 mm, respectively. Using a fine particle cemented carbide insert, the respective coatings are formed on the surface of the cutting tool base material, and the tool 1 is a solid ball end mill with the coating formed thereon. A tool 2 mounted on an insert-type ball end mill having an outer diameter of 20 mm made of cemented carbide was obtained.

  And in each Example and each comparative example, in forming each film | membrane on each said cutting tool base material, using each commercially available arc ion plating apparatus (the Kobe Steel company make: AIP S70), film | membrane formation The type of target was changed, and each film was formed on the surface of each cutting tool base material under predetermined film forming conditions.

(Examples 1-9 and Comparative Examples 1-9)
In Examples 1 to 9 and Comparative Examples 1 to 9, as a target for the above film-forming, and Al _0.55 Cr _0.15 Ti _0.30 and Al _0.55 Cr _0.45 Example 1, Example 2 Al _0.55 Cr _0.15 Ti _0.30 and Al _0.65 Cr _0.35 , Example 3 Al _0.55 Cr _0.15 Ti _0.30 and Al _0.75 Cr _0.25 , Example 4 Al _0.65 Cr _0.10 Ti _0.25 and Al _0.55 Cr _0.45 , Example 5 Al _0.65 Cr _0.10 Ti _0.25 and Al _0.65 Cr _0.35 , Example 6 with Al _0.65 Cr _0.10 Ti _0.25 and Al _0.75 Cr _0.25 , Example 7 with Al _0.75 Cr _0.05 Ti _0.20 and Al _0.55 Cr _0.45 In Example 8, Al _0.75 Cr _0.05 Ti _0.20 and Al _0.65 Cr _0.35 were used, and in Example 9, Al _0.75 Cr _0.05 Ti _0.20 and Al _0.75 Cr _0.25 were used.

On the other hand, in comparative example 1, Al _0.70 Cr _0.30 and Ti, in comparative example 2 Al _0.70 Cr _0.10 Ti _0.20 and Ti, in comparative example 3 Al _0.65 Si _0.10 Ti _0.25 and Ti, in comparative example 4 Al Comparison between _0.65 Si _0.10 Ti _0.25 and Al _0.65 Cr _0.35 , Comparative Example 5 with Al _0.65 Cr _0.10 Ti _0.25 and Al _0.50 Cr _0.50 , and Comparative Example 6 with Al _0.65 Cr _0.10 Ti _0.25 and Al _0.80 Cr _0.20 In Example 7, Al _0.45 Cr _0.30 Ti _0.25 and Al _0.65 Cr _0.35 , in Comparative Example 8 Al _0.80 Cr _0.10 Ti _0.10 and Al _0.65 Cr _0.35 , in Comparative Example 9 Al _0.50 Cr _0.10 Ti _0.40 and Al _0.65 Cr _0.35 And were used.

  And in Examples 1-9 and Comparative Examples 1-9, when forming a film | membrane on the surface of each said cutting tool base material using said each film formation target, said arc ion plating apparatus As shown in Table 1 below, two types of coatings having different compositions are laminated alternately, with the film formation conditions in FIG. 1 being a nitrogen gas pressure of 3.99 Pa, a substrate temperature of 500 ° C., an arc current of 150 A, and a bias voltage of −100 V. I let you.

  And the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction intensity I (200) of the (200) plane in the entire film laminated on the surface of each cutting tool base material in this way, Measured with an X-ray diffractometer using Cu-Kα rays to examine the relationship between I (111) and I (200) and determine the total film thickness laminated on the surface of each cutting tool substrate. These results are shown in Table 1 below. The film thickness of each film laminated as described above was about 10 to 15 nm.

  And about each tool 1 of Examples 1-9 and Comparative Examples 1-9 which laminated | stacked the film | membrane as mentioned above, steel material (S55C, raw material) is cut speed Vc = 100 m / min. , Feed f = 0.2 mm / rev. Under the cutting conditions of axial depth of cut ap = 1mm and radial depth of cut ae = 1mm, complete dry cutting is performed, and the tool life until the maximum wear width of the flank is 0.3mm is obtained. The results are shown in Table 1 below.

  Moreover, about each tool 2 of Examples 1-9 and Comparative Examples 1-9 which laminated | stacked the film | membrane as mentioned above, high-hardness steel (SKD11, HRC60) is used for cutting speed Vc = 380 m / min. , Feed f = 0.5 mm / rev. In the cutting conditions of the axial depth of cut ap = 0.1 mm and the radial depth of cut ae = 0.4 mm, complete dry cutting is performed until the maximum wear width of the flank surface reaches 0.2 mm. The tool life was determined and the results are shown in Table 1 below.

  As a result, the tool 1 and the tool 2 of Examples 1 to 9 in which the Al—Cr—N film and the Al—Cr—Ti—N film satisfying the conditions of the present invention were alternately laminated on the surface of the cutting tool base material. Compared with the tool 1 and the tool 2 of the comparative examples 1-9 which laminated | stacked the film | membrane which does not satisfy | fill the conditions of this invention on the surface of the cutting tool base material, all had a tool life increased significantly.

(Examples 10 to 13)
In Examples 10 to 13, the same Al _0.65 Cr _0.10 Ti _0.25 and Al _0.65 Cr _0.35 as in Example 5 were used as the above-mentioned targets for film formation, and a film was formed on the surface of each of the above cutting tool substrates. In doing so, only the bias voltage of the film forming conditions in the arc ion plating apparatus described above was changed to -70 V in Example 10, -130 V in Example 11, -150 V in Example 12, and in Example 13. At -200 V, as shown in Table 2 below, two types of films having the same composition as in Example 5 were alternately laminated.

  And the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction intensity I (200) of the (200) plane in the entire film laminated on the surface of each cutting tool base material in this way, Measured with an X-ray diffractometer using Cu-Kα rays to examine the relationship between I (111) and I (200) and determine the total film thickness laminated on the surface of each cutting tool substrate. These results are shown in Table 2 below.

  Moreover, about the tool 1 and the tool 2 of Examples 10-13 which laminated | stacked the film | membrane as mentioned above, it calculates | requires a tool life similarly to the case of said Examples 1-9 and Comparative Examples 1-9, respectively, The results are shown in Table 2 below together with the results of Example 5 above.

  As a result, the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction intensity I (200) of the (200) plane in the entire film laminated on the surface of the cutting tool substrate are I (111 )> I (200) The tools 1 and 2 of Examples 5, 10, and 11 satisfying the relationship of I (200) are the tools 1 and 2 of Example 12 that have the relationship of I (111) = I (200), Compared with the tool 1 and the tool 2 of Example 13 in which the relationship of I (111) <I (200) was satisfied, the tool life was improved.

(Examples 14 and 15)
In Examples 14 and 15, Al _0.65 Cr _0.10 Ti _0.25 and Al _0.65 Cr _0.35, which are the same as those in Example 5, were used as the targets for film formation, and Example 5 was performed using the arc ion plating apparatus described above. The same bias voltage was applied to form a film on the surface of each cutting tool substrate.

Here, in Example 14, as shown in Table 3 below, first, only Al _0.65 Cr _0.10 Ti _0.25 was used as a target, and a predetermined film thickness was obtained on the surface of each cutting tool base (Al _0.65 After forming a film of Cr _0.10 Ti _0.25 ) N, Al _0.65 Cr _0.35 and Al _0.65 Cr _0.10 Ti _0.25 were used as targets, and two types of films having the same composition as in Example 5 were alternately laminated.

In Example 15, as shown in Table 3 below, first, only Al _0.65 Cr _0.10 Ti _0.25 was used as a target, and a predetermined film thickness (Al _0.65 Cr _0.10 Ti _0.25 was formed on the surface of each cutting tool substrate. ) After forming the N film, Al _0.65 Cr _0.35 and Al _0.65 Cr _0.10 Ti _0.25 were used as targets, and two types of films having the same composition as in Example 5 were alternately laminated, and then Al _0.65 was used as the target. Using only Cr _0.35 , a (Al _0.65 Cr _0.35 ) N film having a predetermined film thickness was formed.

  And the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction intensity I (200) of the (200) plane in the entire film laminated on the surface of each cutting tool base material in this way, Measured with an X-ray diffractometer using Cu-Kα rays to examine the relationship between I (111) and I (200), and to determine the film thickness of the film laminated on the surface of each cutting tool substrate, These results are shown in Table 3 below.

  Moreover, about the tool 1 and the tool 2 of Examples 14 and 15 which laminated | stacked the film | membrane as mentioned above, it calculates | requires a tool life similarly to the case of said Examples 1-9 and Comparative Examples 1-9, respectively, The results are shown in Table 3 below together with the results of Example 5 above.

As a result, a (Al _0.65 Cr _0.10 Ti _0.25 ) N film having a predetermined thickness was formed on the surface of the cutting tool substrate, and then an (Al _0.65 Cr _0.35 ) N film and (Al _0.65 The tool 1 and the tool 2 of Examples 14 and 15 in which the films of Cr _0.10 Ti _0.25 ) N are alternately laminated have a further increased tool life compared to the tool 1 and the tool 2 of Example 5, In particular, the above-described (Al _0.65 Cr _0.35 ) N film and (Al _0.65 Cr _0.10 Ti _0.25 ) N film are alternately laminated, and the predetermined film thickness is further obtained (Al _0.65 Cr _0.35 ) N. The tool life of the tool 1 and the tool 2 of Example 15 in which the coating film of the above was formed was further increased as compared with the tool 1 and the tool 2 of Example 14.

Claims (5)

On the surface of the cutting tool base material, a general formula (Al _x , Cr _1-x ) N in which the crystal structure is an NaCl type structure (where _x satisfies the condition of <0.55 ≦ x ≦ 0.75). and Al-Cr-N film shown in, the crystal structure is NaCl-type structure formula _{(Al y, Cr 1-y} -z, Ti z) N ( where, y, z is 0.55 ≦ y ≦ 0.75, 0.2 ≦ z ≦ 0.3, and 0.05 ≦ 1-yz ≦ 0.2.) Al—Cr—Ti—N films shown in FIG. A coated cutting tool base material characterized by comprising:   The coated cutting tool substrate according to claim 1, wherein the Al-Cr-N coating has an (111) plane X-ray diffraction intensity I (111) and an (200) plane X-ray diffraction intensity I (200). Satisfy the relationship of I (111)> I (200), and the X-ray diffraction intensity I (111) of the (111) plane and the X-ray diffraction of the (200) plane in the Al—Cr—Ti—N film. The intensity I (200) satisfies the relationship of I (111) <I (200), and the (111) plane X-ray diffraction intensity I (111) and (200) plane of the entire film laminated as described above A coated cutting tool substrate characterized in that the X-ray diffraction intensity I (200) of the above satisfies the relationship of I (111)> I (200).   The coated cutting tool base material according to claim 1 or 2, wherein the coating contacting the surface of the cutting tool base material is the Al-Cr-Ti-N coating. Base material.   The coated cutting tool base material according to any one of claims 1 to 3, wherein a film located on an outermost surface of the film laminated on the surface of the cutting tool base material is the Al-Cr-N. A coated cutting tool substrate characterized by being a film.   The coated cutting tool base material of any one of Claims 1-4 WHEREIN: The said cutting tool base material is comprised with the cemented carbide or the cermet, The coated cutting tool base material characterized by the above-mentioned.