U.S. patent application number 13/154798 was filed with the patent office on 2011-09-29 for method of high-speed turning.
This patent application is currently assigned to SECO TOOLS AB. Invention is credited to Silvia DAHLUND, Tommy LARSSON, Jenni ZACKRISSON.
Application Number | 20110232433 13/154798 |
Document ID | / |
Family ID | 39768677 |
Filed Date | 2011-09-29 |
United States Patent
Application |
20110232433 |
Kind Code |
A1 |
ZACKRISSON; Jenni ; et
al. |
September 29, 2011 |
METHOD OF HIGH-SPEED TURNING
Abstract
A method of high-speed turning of metal using a cutting tool
insert for turning of steel. The cutting tool insert includes a
(006) textured .alpha.-Al.sub.2O.sub.3 coated cemented carbide
grade. The cemented carbide body has 4.5-6.5 wt-% Co and 3-10 wt-%
cubic carbide forming metals and an S-value of 0.77-0.92 and a
coercivity of 10-20 kA/m. The .alpha.-Al.sub.2O.sub.3 layer has a
thickness ranging from 7 to 12 .mu.m and is composed of columnar
grains having a length/width ratio from 2 to 12 and is deposited on
an MTCVD Ti(C,N) layer having a thickness from 4 to 12 .mu.m. The
alumina layer is characterised by a pronounced (006) growth
texture. The alumina layer is the uppermost layer and is
wet-blasted having an Ra value of less than 1 .mu.m, giving the
tool a black and shiny appearance.
Inventors: |
ZACKRISSON; Jenni;
(Fagersta, SE) ; DAHLUND; Silvia; (Soderbarke,
SE) ; LARSSON; Tommy; (Angelsberg, SE) |
Assignee: |
SECO TOOLS AB
FAGERSTA
SE
|
Family ID: |
39768677 |
Appl. No.: |
13/154798 |
Filed: |
June 7, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12168490 |
Jul 7, 2008 |
7985471 |
|
|
13154798 |
|
|
|
|
Current U.S.
Class: |
82/1.11 |
Current CPC
Class: |
B23B 2228/04 20130101;
B23B 2228/105 20130101; Y10T 428/26 20150115; C23C 16/0272
20130101; Y10T 82/10 20150115; C23C 30/005 20130101; B23B 2224/32
20130101; Y10T 428/265 20150115; C23C 16/56 20130101; B23B 2224/04
20130101; Y10T 407/27 20150115; C23C 16/403 20130101; Y10T
428/24975 20150115 |
Class at
Publication: |
82/1.11 |
International
Class: |
B23B 1/00 20060101
B23B001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 13, 2007 |
SE |
0701703-1 |
Claims
1. A method for high-speed turning of a metal, comprising the step
of: subjecting the metal to high-speed turning using a cutting tool
insert comprising a cemented carbide body and a coating, wherein
the cemented carbide body comprises: WC, about 4.5-6.5 wt-% Co; and
about 3-10 wt-% of at least one cubic carbide forming metal
selected from the group consisting of groups IVb, Vb and VIb of the
periodic table; wherein the cemented carbide body has an S-value of
about 0.77-0.92 and a coercivity of about 10-20 kA/m adjacent;
wherein the coating comprises an uppermost layer, wherein the
uppermost layer is about 7-12 .mu.m thick; wherein the uppermost
layer comprises an .alpha.-Al.sub.2O.sub.3 layer textured in the
<006>-directions with a texture coefficient TC(006) greater
than about 2, TC(012), TC(110), TC(113), TC(202), TC(024) and
TC(116) are simultaneously all less than about 1, and TC(104) being
the second highest texture coefficient, the texture coefficient
TC(hkl) being defined by: TC ( hkl ) = I ( hkl ) I 0 ( hkl ) [ 1 n
n = 1 n I ( hkl ) I 0 ( hkl ) ] - 1 ##EQU00003## where
I(hkl)=measured intensity of the (hkl) reflection. Io(hkl)=standard
intensity according to JCPDS card no 46-1212. n=number of
reflections used in the calculation (8). (hkl) reflections used
are: (012), (104), (110), (006), (113), (202), (024) and (116).
2. The method of claim 1, wherein the metal subjected to high-speed
turning is an iron-based alloy.
3. The method of claim 1, wherein the metal subjected to high-speed
turning is steel.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to Swedish Application No.
0701703-1 filed Jul. 13, 2007, the entire disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to coated cutting tool
inserts, which are particularly useful for turning of steel,
preferably at high cutting speeds. More specifically, the present
invention relates to a substrate, which is cemented carbide, onto
which a hard and wear resistant coating is deposited. The coating,
which exhibits an excellent adhesion to the substrate covering all
functional parts thereof, has one or more refractory layers of
which at least one layer is a textured alpha-alumina
(.alpha.-Al.sub.2O.sub.3).
BACKGROUND OF THE INVENTION
[0003] The control of the .alpha.-Al.sub.2O.sub.3 polymorph in
industrial scale was achieved in the beginning of the 1990's with
commercial products based on U.S. Pat. No. 5,137,774. Later
modifications of this patent have been used to deposit
.alpha.-Al.sub.2O.sub.3 with preferred coating textures, described
in U.S. Pat. No. 5,654,035, U.S. Pat. No. 5,980,988, U.S. Pat. No.
5,863,640, U.S. Pat. No. 6,333,103, U.S. Pat. No. 7,011,867, U.S.
Pat. No. 7,094,447, US-A-2006/0199026, and US-A-2006/0141271.
[0004] US-A-2007/0104945 relates to a coated cutting tool insert
comprising a substrate and a coating to be used in metal machining.
The coating contains one or more refractory layers of which at
least one layer is .alpha.-Al.sub.2O.sub.3 and contains columnar
grains. The layer is characterized by a strong (006) diffraction
peak, measured using XRD, and by low intensity of (012), (104),
(113), (024), and (116) diffraction peaks.
[0005] U.S. Pat. No. 7,201,956 discloses a cutting tool composed of
tungsten carbide-based cemented carbide or titanium
carbonitride-based cermet, and a hard coating layer provided on the
surface thereof; wherein the hard coating layer includes an
aluminum oxide layer having an alpha crystal structure, with the
highest peak in the inclination section of the (0001) plane of
crystal grains within ten degrees relative to the normal of the
surface.
[0006] Methods to produce binder phase enriched surface zones on
cemented carbides containing tungsten carbide (WC), binder phase,
and cubic carbide phase are known, e.g. through Tobioka (U.S. Pat.
No. 4,277,283), Nemeth (U.S. Pat. No. 4,610,931) and Yohe (U.S.
Pat. No. 4,548,786). The patents by Tobioka, Nemeth and Yohe
describe methods to accomplish binder phase enrichment in the
surface region by dissolution of the cubic carbide phase close to
the insert surfaces. Their methods require that the cubic carbide
phase contains some nitrogen, since dissolution of cubic carbide
phase at the sintering temperature requires a partial pressure of
nitrogen, nitrogen activity, within the body being sintered
exceeding the partial pressure of nitrogen within the sintering
atmosphere. The nitrogen can be added through the furnace
atmosphere during the sintering cycle and/or directly through the
powder. The dissolution of cubic carbide phase, preferentially in
the surface region, results in small volumes that will be filled
with binder phase giving the desired binder phase enrichment. As a
result, a surface zone consisting of essentially WC and binder
phase is obtained. Although the cubic carbide phase is essentially
a carbonitride phase, the material is herein referred to as a
cemented carbide.
[0007] When cemented carbide cutting tools are used in the
machining of steels, the tool is worn by different mechanisms, such
as abrasive and chemical wear, chipping, and fracturing of the
cutting edge. For a coated tool normally having thin surface layers
of wear resistant carbide, nitride, carbonitride and/or oxide
compounds formed by various vapor deposition techniques, the
coating contributes to increase the abrasive wear resistance, but
it also acts as a thermal barrier for the diffusion of heat from
the cutting surface into the underlying cemented carbide substrate.
A high temperature within the edge region in combination with high
cutting forces result in an increase of the creep deformation
within the affected surface region of the substrate and the cutting
edge deforms plastically. Inserts for machining of steel must have
good deformation resistance, wear resistance, and toughness.
[0008] What is needed is a cutting tool insert with good
deformation resistance, wear resistance, and toughness that is
useful for machining of iron-based alloys, preferably turning of
steel, at fine, medium, rough and interrupted cutting conditions at
high cutting speeds. The invention is directed to these, as well as
other, important needs.
SUMMARY OF THE INVENTION
[0009] In one aspect, the invention is directed to cutting tool
inserts, comprising a cemented carbide body and a coating, [0010]
wherein the cemented carbide body comprises: [0011] WC, [0012]
about 4.5-6.5 wt-% Co; and [0013] about 3-10 wt-% of at least one
cubic carbide forming metal selected from the group consisting of
groups IVb, Vb and VIb of the periodic table; [0014] wherein the
cemented carbide body has an S-value of about 0.77-0.92 and a
coercivity of about 10-20 kA/m adjacent; [0015] wherein the coating
comprises an uppermost layer, [0016] wherein the uppermost layer is
about 7-12 .mu.m thick; [0017] wherein the uppermost layer
comprises an .alpha.-Al.sub.2O.sub.3 layer textured in the
<006>-directions with a texture coefficient TC(006) greater
than about 2, TC(012), TC(110), TC(113), TC(202), TC(024) and
TC(116) are simultaneously all less than about 1, and TC(104) being
the second highest texture coefficient, the texture coefficient
TC(hkl) being defined by:
[0017] TC ( hkl ) = I ( hkl ) I 0 ( hkl ) [ 1 n n = 1 n I ( hkl ) I
0 ( hkl ) ] - 1 ##EQU00001## [0018] where [0019] I(hkl)=measured
intensity of the (hid) reflection. [0020] Io(hkl)=standard
intensity according to JCPDS card no 46-1212. [0021] n=number of
reflections used in the calculation (8). [0022] (hkl) reflections
used are: (012), (104), (110), (006), (113), (202), (024) and
(116).
[0023] In another aspect, the invention is directed to methods for
high-speed turning of a metal, comprising the step of using a
cutting tool insert described herein, especially in iron-based
alloys, including toughness and wear resistance demanding
operations in steel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and together with the description serve to explain
the principles of the invention. In the drawings:
[0025] FIG. 1 shows a cross sectional light optical microscope
picture of a coated insert according to the invention:
[0026] A interior of the substrate
[0027] B binder phase enriched zone
[0028] C titanium carbonitride layer
[0029] D alumina layer
DETAILED DESCRIPTION OF THE INVENTION
[0030] According to the present invention it has now surprisingly
been found that a cemented carbide with a cobalt (Co)-enriched
surface zone provided with a coating comprising a (006) textured
alumina layer post treated by wet blasting is suitable for
high-speed machining applications, preferably in iron based alloys,
most preferably in toughness and wear resistance demanding
operations in steel. The working area is continuous and interrupted
turning at high speed with and without coolant along with finishing
operations with high demands on wear resistance, toughness, and on
precision and surface finish and for machining of stainless steel
where the common problem with built up edge on the cutting tool is
reduced and the surface finish of the work piece is improved. This
surprising improvement can be explained by the combined effect of
cemented carbide with a Co-enriched surface zone, with a (006)
textured alumina and post treatment, preferably wet blasting of the
insert.
[0031] According to the present invention a coated cutting tool
insert is provided consisting of a cemented carbide body with a
composition of about 4.5-6.5 wt-%, preferably about 5-6 wt-% Co,
and about 3-10 wt-% cubic carbide forming metals from groups IVb,
Vb and VIb of the periodic table, preferably Ti, Nb and Ta, and
balance WC. The ratio between the weight concentrations of Ta and
Nb is within about 1.0-3.0, preferably about 1.5-2.5. The ratio
between the weight concentrations of Ti and Nb is within about
0.5-1.5, preferably about 0.8-1.2.
[0032] The cobalt binder phase is highly alloyed with tungsten. The
concentration of W in the binder phase may be expressed as the
S-value=.sigma./16.1, where .sigma. is the magnetic moment of the
binder phase in .mu.Tm3 kg.sup.-1. The S-value depends on the
content of tungsten in the binder phase and increases with
decreasing tungsten content. Thus, for pure cobalt, or a binder
that is saturated with carbon, S=1 and for a binder phase that
contains W in an amount that corresponds to the borderline to
formation of .eta.-phase, S=0.78. It has now been found according
to the present invention that improved cutting performance is
achieved if the cemented carbide body has an S-value within the
range about 0.77-0.92, preferably about 0.79-0.89. The mean grain
size of the carbide phases may be expressed as the coercivity of
the cemented carbide. According to the present invention, it has
been found that a coercivity within about 10 to 20 kA/m, preferably
within about 13 to 17 kA/m, results in improved cutting
performance.
[0033] In a first preferred embodiment the cemented carbide
comprises about 6-10, preferably about 7-8, wt-% cubic carbide
forming metals from groups IVb, Vb and VIb of the periodic table,
preferably Ti, Nb and Ta.
[0034] In a second preferred embodiment the cemented carbide
comprises about 3-6, preferably about 3-5, wt-% cubic carbide
forming metals from groups IVb, Vb and VIb of the periodic table,
preferably Ti, Nb and Ta.
[0035] In a third preferred embodiment at least one surface of the
cemented carbide body discussed above is provided with an about
5-40 .mu.m thick, preferably about 5-30 .mu.m thick, most
preferably about 10-25 .mu.m thick, essentially cubic carbide phase
free and binder phase enriched surface zone with an average binder
phase content in the range about 1.2-2.5 times the nominal binder
phase content.
[0036] The coating comprises a medium temperature chemical vapor
deposition (MTCVD)-layer as the first layer adjacent the substrate
having a thickness of from about 4 to 12 .mu.m, preferably from
about 5 to 10 .mu.m. On top of the MTCVD layer an
.alpha.-Al.sub.2O.sub.3 layer is deposited. The MTCVD-layer
contains an innermost TiN layer of<about 3, preferably about
0.5-2 .mu.m adjacent to the substrate with a Ti(C,N) layer on top.
Preferably, there is also an additional TiN layer inserted in the
Ti(C,N) layer having a thickness of about 0.5-3 .mu.m, preferably
about 1.0-2.0 .mu.m. The TiN layer is placed in the Ti(C,N) layer
about 0.5-2.5 .mu.m below the alumina layer. The first MTCVD
Ti(C,N) layer adjacent the substrate can be substituted by MTCVD
Ti(C,O,N), CVD Ti(C,N), CVD TiN, CVD TiC, MTCVD Zr(C,N), or
combinations thereof.
[0037] The .alpha.-Al.sub.2O.sub.3 layer according to the invention
consists of nucleated .alpha.-Al.sub.2O.sub.3 with columnar grains
with low dislocation density, essentially free from transformation
stresses. The thickness of the alumina layer is from about 7 to 12
.mu.m, preferably about 8 to 11 .mu.m. The alumina layer is
composed of columnar grains with (006) texture, having a
length/width ratio of from about 2 to 12, preferably about 4 to 8.
The .alpha.-Al.sub.2O.sub.3 layer is the uppermost layer.
Typically, the surface roughness is Ra<about 1.0 .mu.m,
preferably about 0.3-0.7 .mu.m.
[0038] The texture coefficients (TC) for the
.alpha.-Al.sub.2O.sub.3 layer is determined as follows:
TC ( hkl ) = I ( hkl ) I 0 ( hkl ) [ 1 n n = 1 n I ( hkl ) I 0 (
hkl ) ] - 1 ##EQU00002## [0039] where [0040] I(hkl)=intensity of
the (hkl) reflection [0041] Io(hkl)=standard intensity according to
JCPDS card no 46-1212 [0042] n=number of reflections used in the
calculation.(hkl) reflections used are: (012), (104), (110), (006),
(113), (202), (024) and (116). The texture of the alumina layer is
as follows: TC(006)>about 2, preferably>about 3 and<about
6, and preferably<about 5. Simultaneously, TC(012), TC(110),
TC(113), TC(202), TC(024) and TC(116) are all<about 1 and
TC(104) is the second highest texture coefficient.
[0043] In a preferred embodiment TC(104)<about 2 and> about
0.5. The total coating thickness is between about 11 and 24 .mu.m,
preferably between about 13 and 21 .mu.m.
[0044] The invention also relates to methods of making cutting tool
inserts according to the description comprising a cemented carbide
substrate consisting of a binder phase of Co, WC and a cubic
carbonitride phase with a binder phase enriched surface zone
essentially free of cubic carbide phase and a coating. A powder
mixture containing about 4.5-6.5 wt-%, preferably about 5-6 wt-%
Co, and about 3-10 wt-% cubic carbide forming metals from groups
IVb, Vb and VIb of the periodic table, preferably Ti, Nb and Ta,
and balance WC is prepared. The ratio between the weight
concentrations of Ta and Nb is within about 1.0-3.0, preferably
about 1.5-2.5. The ratio between the weight concentrations of Ti
and Nb is within about 0.5-1.5, preferably about 0.8-1.2. The raw
materials are mixed with pressing agent. W is added when the raw
materials contain too much C to obtain the desired S-value. In the
opposite case, when the carbon content is too low in the raw
material mixture, pure carbon is added. In this way, the desired
S-value is obtained and the mixture is milled and spray dried to
obtain a powder material with the desired properties. Next, the
powder is compacted and sintered. Sintering is performed at a
temperature of about 1300-1500.degree. C. in a controlled
atmosphere of about 50 mbar followed by cooling.
[0045] In one embodiment, well-controlled amounts of nitrogen are
added through the powder e.g. as nitrides or by performing an
in-situ nitriding in the furnace using e.g. nitrogen gas. The
optimum amount of nitrogen to be added depends on the composition
of the cemented carbide and in particular on the amount of cubic
phases. The exact conditions depend to a certain extent on the
design of the sintering equipment being used. It is within the
purview of the skilled artisan to determine and to modify the
nitrogen addition and the sintering process in accordance with the
present specification in order to obtain the desired results.
[0046] The cemented carbide surface is coated with a Ti(C,N) layer
and possibly intermediate layers by chemical vapor deposition (CVD)
and/or MTCVD. Subsequently, a CVD process incorporating several
different deposition steps, is used to nucleate
.alpha.-Al.sub.2O.sub.3 at a temperature of about 1000.degree. C.
In these steps the composition of a CO.sub.2+CO+H.sub.2+N.sub.2 gas
mixture is controlled to result in an O-potential required to
achieve (006) texture. The .alpha.-Al.sub.2O.sub.3-layer is then
deposited by conventional CVD at 1000.degree. C. The exact
conditions depend on the design of the coating equipment being
used. It is within the purview of the skilled artisan to determine
the gas mixture in accordance with the present invention.
[0047] Finally, the .alpha.-Al.sub.2O.sub.3 is post treated with a
surface polishing method, preferably wet-blasting, in order to
decrease the surface roughness.
[0048] The present invention also relates to the use of a cutting
tool insert according to the above in continuous fine, medium,
rough and interrupted turning of steel at high speed with and
without coolant along with finishing operations with high demands
on wear resistance, toughness and on precision and surface finish.
The present invention also relates to the use of a cutting tool
according to above for machining of stainless steel where the
common problem with built up edge on the cutting tool is reduced
and the surface finish of the work piece is improved.
[0049] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which this invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods and materials are now described.
All publications mentioned hereunder are incorporated herein by
reference. Unless mentioned otherwise, the techniques employed or
contemplated herein are standard methodologies well known to one of
ordinary skill in the art. The materials, methods, and examples are
illustrative only and not limiting.
[0050] The present invention is further defined in the following
Examples, in which all parts and percentages are by weight and
degrees are Celsius, unless otherwise stated. It should be
understood that these examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only. From the above discussion and these examples, one skilled in
the art can ascertain the essential characteristics of this
invention, and without departing from the spirit and scope thereof,
can make various changes and modifications of the invention to
adapt it to various usages and conditions.
Example 1
Cemented Carbide Inserts
[0051] Cemented carbide inserts of type CNMG120408, CCMT09T308 and
TPUN160308 were produced according to the invention by conventional
milling of the raw material powders, pressing of the green compacts
and subsequent sintering at 1430.degree. C. The inserts were also
subjected to traditional edge preparation and dimensional grinding.
Data for the inserts after sintering is shown in Table 1.
TABLE-US-00001 TABLE 1 Compositions and Physical Data Sub- Co, Ta,
Nb, Ti, Coercivity, Gradient, strate wt-% wt-% wt-% wt-% kA/m
S-value .mu.m A 5.5 3.2 2.0 2.3 13.5 0.85 15 B 5.8 3.2 2.0 2.3 15
0.84 14 C 5.1 3.2 2.0 2.3 14 0.87 12
Example 2
Coatings
[0052] Inserts from Example 1 were MTCVD and CVD coated.
[0053] The first layer was Ti(C,N) deposited by MTCVD using
acetonitrile as a carbon/nitrogen source. In the following steps an
alumina layer was deposited and the composition of
CO.sub.2+CO+H.sub.2+N.sub.2 gas mixture was controlled to result in
an O-potential required to achieve (006) texture. The thickness of
the different layers was controlled by the deposition time. The
thickness and texture coefficients for layers are shown in table
2.
TABLE-US-00002 TABLE 2 Thickness and texture coefficients of the
layers TiCN, .alpha.-Al.sub.2O.sub.3, TC TC TC TC TC TC TC TC
Coating .mu.m .mu.m (012) (104) (110) (006) (113) (202) (024) (116)
A 8 10 0.20 1.12 0.13 5.72 0.12 0.09 0.14 0.47 B 6 8.5 0.31 1.52
0.13 4.70 0.17 0.20 0.20 0.77
Example 3
[0054] Inserts from Example 1 and Example 2 and a competitor grade
(comparative) relevant to the application area were tested with
respect to deformation resistance. [0055] Work piece: Cylindrical
bar [0056] Material: Ck45 [0057] Insert type: TPUN160308 [0058]
Cutting speed: 900 m/min [0059] Feed: 0.3 mm/rev [0060] Depth of
cut: 3.0 mm [0061] Remarks: dry turning The inserts were inspected
after 25 seconds of cutting. Table 3 shows the degree of
deformation in arbitrary units of the cutting edge.
TABLE-US-00003 [0061] TABLE 3 Deformation of the cutting edge after
25 seconds in cut Degree of deformation, Sample arbitrary units.
Invention: Substrate B + Coating A 0.10 Invention: Substrate B +
Coating B 0.12 Comparative: Competitor grade W 0.28
Example 4
[0062] Inserts from Example 1 and Example 2 and competitor grades
(comparative) relevant to the application area were tested with
respect to tool life. [0063] Work piece: Cylindrical bar [0064]
Material: Ck45 [0065] Insert type: CNMG120408 [0066] Cutting speed:
400 m/min [0067] Feed: 0.45 mm/rev [0068] Depth of cut: 2.0 mm
[0069] Remarks: Coolant Measurements of wear, vbb in mm after 12
minutes time in cut are shown in Table 4.
TABLE-US-00004 [0069] TABLE 4 Wear measurements after 12 minutes
time in cut Sample: Wear, vbb Invention: Substrate A + Coating A
0.18 mm Invention: Substrate B + Coating A 0.15 mm Comparative:
Competitor grade X >1.0 mm (edge break down) Comparative:
Competitor grade Y >1.0 mm (edge break down) Comparative:
Competitor grade Z 0.27 mm Comparative: Competitor grade W 0.38
mm
Example 5
[0070] Inserts from Example 1 and Example 2 and a competitor grade
(comparative) relevant to the application area were tested in a
finishing operation where the machining mode was facing. [0071]
Work piece: Cylindrical bar, diameter 80 mm. [0072] Material:
100Cr6 [0073] Insert type: CCMT09T308-F1 [0074] Cutting speed: 250
m/min (with coolant) [0075] Feed: 0.15 mm/rev [0076] Depth of cut:
1.5 mm The result expressed as wear after 40 facings are presented
in Table 5.
TABLE-US-00005 [0076] TABLE 5 Wear after 40 facings. Sample Wear
(vbb in mm) after 40 facings Invention: Substrate B + Coating B
0.09 Invention: Substrate C + Coating B 0.08 Comparative:
Competitor grade X 0.16
Example 6
[0077] Inserts from Example 1 and Example 2 and competitor grades
(comparative) relevant to the application area were tested with
respect to toughness in longitudinal turning with interrupted cuts.
[0078] Work piece: Cylindrical bar diameter 160 mm, with four axial
grooves [0079] Material: Ck45 [0080] Insert type: TPUN160308 [0081]
Cutting speed: 120 m/min [0082] Feed 0.1, 0.12, 0.16, 0.20, 0.25,
0.32 mm/rev gradually increased after 10 mm length of cut [0083]
Depth of cut: 2.0 mm [0084] Remarks: dry turning Tool life
criteria: Gradually increased feed until edge chipping occurs. 9
edges of each variant were tested. The test results in Table 6 show
that a product according to the present invention has increased
edge toughness compared to the comparative examples.
TABLE-US-00006 [0084] TABLE 6 Average feed when edge chipping
occurs, mean value for 9 edges. Sample Mean feed rate at breakage
(mm/rev) Invention substrate A + Coating B 0.21 Invention substrate
C + Coating A 0.19 Comparative: Competitor grade Y 0.17
Comparative: Competitor grade W 0.16 Comparative: Competitor grade
V 0.16
Example 7
[0085] Inserts from Example 1 and Example 2 and competitor grades
(comparative) relevant to the application area were tested in a
finishing operation in stainless steel. The operation mode was
facing of small diameter bars. [0086] Work piece: Cylindrical bar,
diameter 55 mm, length 178 mm [0087] Material: 316L [0088] Insert
type: CCMT09T308-F1 [0089] Cutting speed: 120 m/min (with coolant)
[0090] Feed: 0.25 mm/rev [0091] Depth of cut: 0.8 mm Tool life
criteria were flank wear or notch wear >0.15 mm The number of
facings performed before end of tool life is shown in Table 7
below.
TABLE-US-00007 [0091] TABLE 7 Number of facings performed and
corresponding wear measurements Sample: No. of facings Wear, mm
Invention: Substrate A + Coating A 33 0.15 (flank) Invention:
Substrate C + Coating B 39 0.17 (notch) Comparative: Competitor
grade X 21 0.23 (notch) Comparative: Competitor grade Y 11 0.15
(flank) Comparative: Competitor grade W 18 0.17 (flank)
[0092] When ranges are used herein for physical properties, such as
molecular weight, or chemical properties, such as chemical
formulae, all combinations and subcombinations of ranges specific
embodiments therein are intended to be included.
[0093] The disclosures of each patent, patent application, and
publication cited or described in this document are hereby
incorporated herein by reference, in their entirety.
[0094] Those skilled in the art will appreciate that numerous
changes and modifications can be made to the preferred embodiments
of the invention and that such changes and modifications can be
made without departing from the spirit of the invention. It is,
therefore, intended that the appended claims cover all such
equivalent variations as fall within the true spirit and scope of
the invention.
* * * * *