CVD coated cutting tool
A coated cutting tool for chip forming machining of metals includes a substrate having a surface coated with a chemical vapour deposition (CVD) coating. The substrate is coated with a coating having a layer of α-Al 2 O 3 , wherein the α-Al 2 O 3 layer exhibits a texture coefficient TC(0 0 12)≥7.2 and wherein the ratio of I(0 0 12)/I(0 1 14)≥0.8. The coating further includes a MTCVD TiCN layer located between the substrate and the α-Al 2 O 3 layer. The MTCVD TiCN layer exhibits a pole figure, as measured by EBSD, in a portion of the MTCVD TiCN layer parallel to the outer surface of the coating and less than 1 μm from the outer surface of the MTCVD TiCN, wherein a pole plot based on the data of the pole figure, with a bin size of 0.25° over a tilt angle range of 0°≤β≤45° from the normal of the outer surface of the coating shows a ratio of intensity within β≤15° tilt angle to the intensity within 0°≤β≤45° of ≥45%.
1. A coated cutting tool comprising:
a substrate coated with a coating including a layer of α-Al 2 ) 3 , wherein a thickness of the α-Al 2 O 3 layer is 2-4 μm and wherein said α-Al 2 O 3 layer exhibits a texture coefficient TC(hkl), as measured by X-ray diffraction using CuKa radiation and θ- 2 θscan, defined according to Harris formula
TC
(
hkl
)
=
I
(
hkl
)
I
0
(
hkl
)
[
1
n
∑
n
=
1
n
I
(
hkl
)
I
0
(
hkl
)
]
-
1
where I(hkl) is the measured intensity (integrated area) of the (hkl) reflection, I 0 (hkl) is the standard intensity according to ICDD's PDF-card No. 00-010-0173, n is the number of reflections used in the calculation, and where the (hkl) reflections used are (1 0 4), (1 1 0), (1 1 3), (0 2 4), (1 1 6), (2 1 4), (3 0 0) and (0 0 12),
wherein TC(0 0 12) ≥7.2, and wherein the ratio of I(0 0 12)/I(0 1 14) ≤0.8, and wherein said coating further includes a MTCVD TiCN layer located between the substrate and the α-Al 2 O 3 layer, wherein the thickness of said MTCVD TiCN layer is 2-3 μm and wherein said MTCVD TiCN layer exhibits a {211} pole figure as measured by EBSD in a portion of the MTCVD TiCN layer parallel to an outer surface of the coating and less than 1 μm from an outer surface of the MTCVD TiCN, wherein a pole plot based on the data of the pole figure, with a bin size of 0.25° over a tilt angle range of 0°≤β≤45° from the normal of the outer surface of the coating shows a ratio of intensity within β≤15° tilt angle to the intensity within 0°≤β≤45° of ≥45%.
2. The coated cutting tool in accordance with claim 1 , wherein said MTCVD TiCN layer exhibits a {110}pole figure as measured by EBSD, wherein a pole plot based on the data of the pole figure, with a bin size of 0.25° over a tilt angle range of 0°≤β≤45° from a normal of the outer surface of the coating shows a ratio of intensity within β≤15° tilt angle to the intensity within 0°≤β≤4 5 ° of ≤30% .
3. The coated cutting tool in accordance with claim 1 , wherein the thickness of the β-Al 2 O 3 layer is 2.5-3.5 μm.
4. The coated cutting tool in accordance with claim 1 , wherein the coating further includes a bonding layer having a HTCVD deposited TiN, TiCN, TiCNO and/or TiCO or a combination thereof, the bonding layer being located outermost of the MTCVD TiCN layer and adjacent to the β-Al 2 O 3 layer.
5. The coated cutting tool in accordance with claim 4 , wherein the thickness of the bonding layer is 0.5-1 μm.
6. The coated cutting tool in accordance with claim 1 , further comprising an innermost TiN layer adjacent to the substrate.
7. The coated cutting tool in accordance with claim 6 , wherein the thickness of said innermost TiN layer is 0.3-0.6 μm.
8. The coated cutting tool in accordance with claim 1 , wherein the substrate is cemented carbide, cermet, ceramic.
9. The coated cutting tool in accordance with claim 1 , wherein the substrate is cemented carbide with a Co content of 8-15 wt %.
10. The coated cutting tool in accordance with claim 1 , wherein the cutting tool is a milling insert.