EP-4494788-B1 - CUTTING TOOL

EP4494788B1EP 4494788 B1EP4494788 B1EP 4494788B1EP-4494788-B1

Inventors

SUZUKI, YUTA
KANAOKA, HIDEAKI
IMAMURA, SHINYA

Dates

Publication Date: 20260506
Application Date: 20230428

Claims (2)

A cutting tool comprising a substrate (10) and a coating film (20) provided on the substrate, wherein the coating film includes a first layer (21) and a second layer (22), the second layer is provided at a position close to the substrate with respect to the first layer, a thickness of the coating film is 1.5 µm or more and 30 µm or less, wherein the thickness is measured using the method described in the description, an average thickness of the first layer is 1.0 µm or more and 20 µm or less, an average thickness of the second layer is 0.5 µm or more and 10 µm or less, the first layer is constituted of a multilayer structure in which a first unit layer (1) and a second unit layer (2) are alternately layered, wherein the number of layered layers in the first layer is 10 or more and 5000 or less, an average thickness of the first unit layer is 2 nm or more and 50 nm or less, wherein the average thickness of the first unit layer is measured using the method described in the description, an average thickness of the second unit layer is 2 nm or more and 50 nm or less, wherein the average thickness of the second unit layer is measured using the method described in the description, the first unit layer is composed of Ti a Al 1-a-b B b N, where 0.30 ≤ a ≤ 0.50 , and 0 < b ≤ 0.10 , the second unit layer is composed of Ti c Al 1-c N, where 0.70 ≤ c ≤ 1.00 , wherein the composition of the first unit layer and the composition of the second unit layer are measured using the method described in the description, in the first layer, a percentage (T2/T1)×100 of the number T2 of atoms of titanium to a total T1 of the numbers of atoms of titanium and aluminum is 60% or more, wherein the percentage (T2/T1)×100 in the first layer is measured using the method described in the description, the second layer is constituted of a multilayer structure in which a third unit (3) layer and a fourth unit layer (4) are alternately layered, wherein the number of layered layers in the second layer is 10 or more and 5000 or less, an average thickness of the third unit layer is 2 nm or more and 100 nm or less, wherein the average thickness of the third unit layer is measured using the method described in the description, an average thickness of the fourth unit layer is 2 nm or more and 100 nm or less, wherein the average thickness of the fourth unit layer is measured using the method described in the description, the third unit layer is composed of Ti d Al 1-d-e B e N, the fourth unit layer is composed of Ti f Al 1-f-g B g N, where 0.25 ≤ d < 0.45 , 0 < e ≤ 0.10 , 0.35 ≤ f < 0.55 , 0 < g ≤ 0.10 , and 0.05 ≤ f − d ≤ 0.20 , wherein the composition of the third unit layer and the composition of the fourth unit layer are measured using the method described in the description, and in an X-ray diffraction spectrum of the second layer, a ratio I(200)/I(002) of a peak intensity I(200) originated from a (200) plane to a peak intensity I(002) originated from a (002) plane is 2 or more, and a half width of a peak originated from the (002) plane is 2 degrees or more, wherein the ratio I(200)/I(002) is measured using the method described in the description.
The cutting tool according to claim 1, wherein a nano indentation hardness of the first layer at 25°C in accordance to ISO 14577-1,2015 is 30 GPa or more.

Description

TECHNICAL FIELD The present disclosure relates to a cutting tool. BACKGROUND ART Conventionally, in order to improve performance of a cutting tool, development has been advanced with regard to a coating film that coats a surface of a substrate composed of a cemented carbide, a cubic boron nitride sintered material, or the like (for example, PTL 1). The patent document WO 2022/176057 A1 (PTL 1) discloses a cutting tool comprising a substrate and a coating film thereon which is made of a first and a second multilayer structures alternately stacked from the substrate. The patent document EP 3 269 479 A1 discloses another coating system to provide coated cutting tools with long service life wherein the coating is made of alternating layers that comprise each TiAlMeN compounds. CITATION LIST PATENT LITERATURE PTL 1: WO 2022/176057 SUMMARY OF INVENTION A cutting tool according to the present disclosure is defined in claim 1 and includes a substrate and a coating film provided on the substrate, wherein the coating film includes a first layer and a second layer,the second layer is provided at a position close to the substrate with respect to the first layer,the first layer is constituted of a multilayer structure in which a first unit layer and a second unit layer are alternately layered,an average thickness of the first unit layer is 2 nm or more and 50 nm or less,an average thickness of the second unit layer is 2 nm or more and 50 nm or less,the first unit layer is composed of TiaAl1-a-bBbN, where 0.30≤a≤0.50, and 0<b≤0.10,the second unit layer is composed of TicAl1-cN, where 0.70≤c≤1.00,in the first layer, a percentage (T2/T1)×100 of the number T2 of atoms of titanium to a total T1 of the numbers of atoms of titanium and aluminum is 60% or more,the second layer is constituted of a multilayer structure in which a third unit layer and a fourth unit layer are alternately layered,an average thickness of the third unit layer is 2 nm or more and 100 nm or less,an average thickness of the fourth unit layer is 2 nm or more and 100 nm or less,the third unit layer is composed of TidAl1-d-eBeN,the fourth unit layer is composed of TifAl1-f-gBgN, where 0.25≤d<0.45, 0<e≤0.10, 0.35≤f<0.55, 0<g≤0.10, and 0.05≤f−d≤0.20, andin an X-ray diffraction spectrum of the second layer, a ratio I(200)/I(002) of a peak intensity I(200) originated from a (200) plane to a peak intensity I(002) originated from a (002) plane is 2 or more, and a half width of a peak originated from the (002) plane is 2 degrees or more. BRIEF DESCRIPTION OF DRAWINGS Fig. 1 is a schematic cross sectional view showing an exemplary configuration of a cutting tool according to a first embodiment.Fig. 2 is a schematic cross sectional view showing an exemplary configuration of a film forming device.Fig. 3 is a schematic cross sectional view showing the exemplary configuration of the film forming device.Fig. 4 is a diagram for illustrating a measurement region when measuring a diameter of a maximum inscribed circle of a crystal grain of a first layer.Fig. 5 is a diagram for illustrating a method of measuring the diameter of the maximum inscribed circle of the crystal grain of the first layer, and schematically showing a bright visual field image of a measurement visual field.Fig. 6 is a diagram for illustrating a positional relation between the crystal grain and each of first and second unit layers. DETAILED DESCRIPTION [Problem to be Solved by the Present Disclosure] In recent years, a demand for cost reduction has been increased and a tool has been required to have a longer life. For example, a cutting tool having a long tool life has been required also in a turning process for stainless steel. Thus, it is an object of the present disclosure to provide a cutting tool having a long tool life. [Advantageous Effect of the Present Disclosure] The cutting tool of the present invention is defined by the appended claims and can have a long tool life. [Description of Embodiments] First, embodiments of the present disclosure will be listed and described. A cutting tool according to the present invention includes a substrate and a coating film provided on the substrate, wherein the coating film includes a first layer and a second layer,the second layer is provided at a position close to the substrate with respect to the first layer,the first layer is constituted of a multilayer structure in which a first unit layer and a second unit layer are alternately layered,an average thickness of the first unit layer is 2 nm or more and 50 nm or less,an average thickness of the second unit layer is 2 nm or more and 50 nm or less,the first unit layer is composed of TiaAl1-a-bBbN, where 0.30≤a≤0.50, and 0<b≤0.10,the second unit layer is composed of TicAl1-cN, where 0.70≤c≤1.00,in the first layer, a percentage (T2/T1)×100 of the number T2 of atoms of titanium to a total T1 of the numbers of atoms of titanium and aluminum is 60% or more,the second layer is constituted of a multilayer structur