FR2558087A1 - CUTTING TOOL AND METHOD OF MANUFACTURING THE SAME - Google Patents

Abstract

THE INVENTION CONCERNS METAL MACHINING. THE CUTTING TOOL WHICH IS THE SUBJECT OF THE INVENTION IS OF THE TYPE INCLUDING A BASE 1 WHOSE ACTIVE SURFACE 2 IS A WEAR-RESISTANT COATING 3 INCLUDING MICROCRYSTALS OF A COMPOUND WITH A HIGH MELTING POINT CONSTITUTED BY AT LEAST A METAL AND AT LEAST ONE ELEMENT OF GROUP C, N, O, B, AND IS CHARACTERIZED IN THAT THE GREATEST NUMBER OF MICROCRYSTALS OF THE SAID CONSISTS OF A HIGH MELTING POINT, CONSTITUTES AT LEAST ONE METAL AND AT LEAST ONE ELEMENT OF THE GROUP C, N, O, B, AND FURTHER INCLUDING IF, IS ORIENTED PARALLEL TO THE ACTIVE SURFACE 2 OF THE BASE 1 BY A SAME CRYSTALLOGRAPHIC PLANE 4, 5. THE INVENTION APPLIES IN PARTICULAR TO THE MANUFACTURE OF CUTTING TOOLS FROM DIFFERENT TOOL MATERIALS.

Description

The present invention relates to the machining of metals and in particular to

  object a cutting tool and a method

of manufacturing said tool.

  The invention is particularly applicable to the manufacture of cutting tools from different tool materials. One of the current trends in the development of

  metal machining consists in perfecting the characteristics

  characteristics of use of the cutting tool overlapping

  its surface a wear-resistant layer.

  So far, efforts in this area have tended to improve the properties of the

  cut by choosing in an appropriate manner the

  chemical composition of coatings likely to be the

  more effective in them; concrete conditions of the use

  tion. However, it is also possible to improve

  the properties of the tool by improving the structure of the coatings.

  A cutting tool is known (see, for example, application accepted United Kingdom No. 1303910, class C23C 11/08, 24.01.1973) whose hard alloy base bears a

  wear-resistant coating that includes micro-

  crystals of a compound with a high melting point of a metal and elements of group C, N and / or B. In this cutting tool, metals of the group Ti, Zr, Hf, V, Nb are used, Your

  as wear-resistant coating metals.

  Also known is a method of manufacturing cutting tools (see, for example, the same application accepted Great Britain No. 1303910, class C23C 11/08, 24.0141973) which consists in bringing the base to a temperature of 10000 C to 1100 C, introducing agents containing metals and elements of group C, N, B, and performing a chemical reaction between them to form a coating comprising

  microcrystals of high melting point compound.

  However, the cutting tool considered, manufactured according to the method described, has a high surface energy, which ensures its active action, by adhesion and diffusion, on the material to be machined. Another cutting tool is known (see, for example, United States of America Patent No. 4169913, class B 23 15/18, 1979) having a base whose active surface bears a coating resistant to wear, comprising crystals of a high-melting compound of metals and elements of group C, N, B, O.

  However, this cutting tool also has an energy

  high superficial level, which leads to its active action

  on the material to be machined, by adhesion and diffusion.

  There is also known a method of manufacturing cutting tools (see same United States Patent No. 4169913, class B 23 B 15/18, 1979), which consists of evaporating and ionizing a metal under vacuum. subsequently introducing into the vacuum a gaseous agent comprising C, N, B, O group elements and reacting therewith metals until the wear-resistant coating is formed. According to this method the metals are evaporated by means of an electron beam using an electrode of a special type intended for their ionization, the reaction of the metals with the elements of group C, N, O, B is performing on the

unheated base.

  In this method of manufacturing the cutting tool, the thermal regime for the application of the coating causes the absorption of the energy of the metals in reaction with elements of the group C, N, O, B by the unheated base , resulting in the formation of a coating having a high level of free surface energy, which, at its

  turn, decreases the holding of the cutting tool.

  In addition, the operation of evaporation and ionization

  metals do not provide a high degree of ioni-

  of the latter and also leads to the formation of a coating with a high level of free surface energy and decreases, as has just been mentioned, the

holding the cutting tool.

  Another method of manufacturing cutting tools is also known (see Kasianov S.V.'s thesis, "Study of cutting properties and search for new

  ways of improving tools with a resistant coating

  so much to wear ", Moscow, 1979," Moskovsky Stanko-instru-

  mentalny institut ", p.50), which consists in evaporating and vacuum ionizing at least one metal, heating the base of the cutting tool and cleaning its active surface by ion bombardment of at least one metal, introducing into the vacuum a gaseous reactant and reacting at least one metal with at least one of its elements up to the

  formation of a wear-resistant coating.

  However, this method of manufacturing the tool does not make it possible to obtain a minimum value of the free energy of the active surface. This causes an intense interaction of the active surface with the material to be machined, by adhesion and diffusion and, consequently, a decrease

the holding of the cutting tool.

  It was therefore proposed to create a cutting tool whose coating would have a structure to increase its strength, and to develop a method of manufacturing said cutting tool, wherein the thermal regime and the pressure used for the cutting. application of the wear-resistant coating would make it possible to increase

of the cutting tool.

  This problem is solved by the fact that the cutting tool of the type comprising a base whose active surface carries

  a wear-resistant coating comprising micro-

  crystals of a compound with a high melting point of at least one metal with at least one element of the group C, N. 0, B, is characterized, according to the invention, in that the greatest number of microcrystals of the compound to high melting point formed by at least one metal with at least one element of the group C, N, O, further comprising Si, is oriented parallel to the active surface of the base

  by the same crystallographic plane.

  It is rational that said crystallographic plane of orientation of the microcrystals has an energy

minimal superficial. -

  The problem explained above is also solved by

  that the manufacturing process of the cutting tool

  dique, of the type consisting of evaporating and ionizing under vacuum at least one metal, heating the base of the cutting tool and cleaning its active surface by bombarding ions of at least one metal, to introduce into said vacuum a gaseous reactant and reacting at least one metal with at least one element to form a wear-resistant coating consisting of a high-melting compound comprising microcrystals, is characterized, according to the invention, in that the temperature at which the base of the cutting tool is carried is less than C less than the temperature of its softening,

  that this heating temperature of the base is now

  bare, during the formation of the coating, in a beach

  ranging from this heating temperature of the base jus-

  than at +50 C, adjusting simultaneously

2558087,

  the pressure of the gaseous reagent in the range of 13.33 Pa

at 1.33 × 10 2 Pa.

  Thanks to the present invention, the interaction of

  the liner of the cutting tool and the material to be machined is reduced to a minimum, which results in a decrease in the intensity of the adhesion, chemical and diffusion processes between the cutting tool and the material to be machined, which, in turn, contributes to an increase in

holding the cutting tool.

  The invention will be better understood and other purposes, details and advantages thereof will become more apparent in the

  light of the explanatory description which will follow from

  various embodiments given solely by way of nonlimiting example, with reference to the appended nonlimiting drawings in which: FIG. 1 represents an overall view of a cutting tool manufactured according to the method according to the invention ( with partial tearing); FIG. 2 represents an overall view of the sectional tool of FIG. 1, with the crystallographic planes of the microcrystals having the minimum surface energy;

(seen with partial tearing).

  The cutting tool comprises a base 1 (FIG. 1) whose active surface 2 carries a coating 3 formed by the

TiN compound.

  In FIG. 1, the microcrystals of the TiN compound appear schematically (on a very enlarged scale).

  oriented parallel to the base 1 by their crys-

4 identical.

  Figure 2 shows schematically (on a very enlarged scale) the microcrystals of the TiN compound oriented

  parallel to the base 1 by their crystallographic planes

  5 with minimal surface energy.

  The manufacturing process of the cutting tool

  diqué consists in evaporating and vacuum ionizing at least one metal. Then the base of the cutting tool is heated and its active surface is cleaned by ion bombardment of the metal. The temperature at which the base of the cutting tool is carried is less than 100 ° C. lower than the temperature of its softening and the temperature

  heating the base during the formation of the coating

  is maintained within the range of this temperature

  This is done, introducing a gaseous reactant containing at least one element of the group C, N, O, B, Si, whose pressure is adjusted within the limits of 13.33 Pa to 1.33 × 10. -2 Pa, and reacts at least one metal with at least one element of the group C, N, O,

  B, Si, this reaction leading to the formation of: -revet-

  wear-resistant composition comprising microcrystals of a compound having a high melting point of at least one metal with at least one element of the group C, N, O, B, Si, these

  monocrystals being oriented, by the same crystallographic plane.

  parallel to the active surface of the base.

  The cutting tool works as follows.

  During machining of the metal, the wear-resistant coating 3 (FIGS. 1, 2) acts on the metal to be machined under the conditions of high temperatures and pressures which are created in the cutting zone. The fact that a maximum number

  of microcrystals is oriented, by the same plane,

  llographic 4, parallel to the active surface 2 of the base 1, reduces the free energy of the surface

  2 of base 1 and to decrease by the same

  interaction of active surface molecules

2 and the material to be machined.

  When the surface energy of the crystallographic plane

  (Figure 2) microcrystal orientation is minimal, the interaction of the molecules decreases to a minimum value, which further increases the holding of

the cutting tool.

  Concrete but non-limiting examples of realization

  of the invention are described below.

Example 1

  Drill bits 5 mm in diameter and X-ray examination samples were made of the structure of a steel coating of the following composition: C Cr WV Mo Fe 0.85 3.6 6.0 2.0 5, 0 rest The steel tempera- ture is 560 C. The cleaned drills and the test specimen to be X-rayed in the coating structure are placed in special cases and at

  introduced simultaneously into a vacuum chamber containing

  mant a titanium cathode. A depression of 65.10-3 Pa was created in the chamber and an electric arc was initiated thereby effecting evaporation and ionization of the titanium.

  The drills and sample were applied to

  put on X-ray examination an accelerated negative voltage

  the positively charged titanium ions and, by bombarding the active surface of the drills and the sample with the titanium ions, their surfaces were cleaned

  and heated the base. Then the voltage applied was

  to the drills and the sample. At the same time, nitrogen was introduced into the chamber, which

2558087.

  reaction with titanium forming a coating

  high melting point TiN compound, comprising microparticles

  crystals. The application of the TiN coating on the active surface of the drills and the sample was carried out at different drill heating regimes and test samples as well as at different values of the

nitrogen pressure.

  Each diet was tested on another batch of drills in the presence of another sample. The degree of orientation of the microcrystals of the high-melting compound TiN was evaluated by applying the X-ray examination method of the coating structure according to the height of the

  X-ray diffraction point on the crystallographic plane

  graphs 4 (5) of surface energy microcrystal

  minimal. The highest height of the diffrac-

  X-ray on the 4 (5) plane recorded for the relevant series of tests was taken for 100%, and it is with respect to this height that the height of the diffraction points in this plane of the microcrystals was evaluated.

TiN during the other tests.

  Five drills taken from each batch of drills made with the TiN high-melting compound coating were tested to drill 15 mm deep holes in a steel of the following composition: C Fe 0.42 0.49 the rest on a vertical drill at the following speeds: - speed: 45 m / min

- advance: 0.13 mm.

  The results of the tests of the lots of forests and samples

  The samples to be subjected to X-ray examination of the structure, manufactured at 9 different regimes, are summarized in Table 1 given below. As shown by the results of the tests, the greatest resistance of the drills is obtained when the heating temperature of the base of the drill before the introduction of the nitrogen is 500 to 550 C, the

  nitrogen pressure is 1.19 Pa and the heating temperature is

  Drilling of the drills during the reaction between titanium and nitrogen is within the range of + 50 to 500 C. It should be noted that drills with a coating of

  high melting point TiN compound comprising microparticles

  crystals, the majority of which are oriented, by their plane 4 (5), parallel to the active surface of the

  basese distinguish by their greater holding.

Example 2

  Drills 5 mm in diameter and hard alloy samples containing 92% WC were manufactured, the remainder being Co, at a softening temperature of 700 to 720 C, in order to subject their structure to X-ray examination. The cleaned drill bits and the sample to be X-rayed are simultaneously introduced into a vacuum chamber containing a 50% Ti and 50% Hf alloy cathode. The application of the coating was carried out in a manner analogous to that used in the case of Example 1, with the difference that the vacuum chamber contained a 50% Ti and 50% Hf alloy cathode. The high melting compound (Ti, Hf) N coating

  was applied to the surface of the drills and samples

  to different forest heating regimes and

  samples, and at different nitrogen pressures.

  The degree of orientation of the microcrystals of the high melting compound was evaluated in the same manner as in

example n 1.

  Five drills taken from each batch of drill bits manufactured with high melting compound (Ti, Hf) N coating were tested to drill holes in the graphite on a vertical drill operating at the following cutting speeds: - speed: 68 m / min - advance: 0.18 mm / rev

- depth of the hole: 16 mm.

  The results of the tests of the drills and samples

  The following diets are given in the table below. As shown by the results of the largest tests held of the drills is obtained when the heating temperature of the hard alloy base before the introduction of nitrogen is 600 to 7000 C, the nitrogen pressure is 6.65.10 -1 Pa and the heating temperature of the hard alloy base during application

  the coating is 100 to 600 C.

  It should be noted that drills having a coating of high melting point compound (Ti, Hf) N, comprising

  microcrystals, the majority of which are oriented

  same to the active surface of the base by their plan 4

  (5) possessing the minimum surface energy, discloses

  tinguished by their greater hold.

  The present invention can be used for machining

  metals by different cutting modes.

  In addition, the present invention makes it possible to raise

  quality of decorative and anticorrosive coatings.

  The present invention also makes it possible to improve the

  characteristics of use of parts in assemblies

friction.

BOARD

  N ex- Tool Heating temperature of the base example

during the bom-

lamination of the coating

of cement, tal, C C

1 2 3 4

  I1 Steel drills 500 400 coated 500 400 compound 500 400 high melting 500 400 TiN 500 400

550 40

550 50

550 400

550 500

  2 Alloyed drills 650 600 hard ge, coated 650 650 650 650 650 650 high melting point (Ti, Hf) N 650 600

650 40

650 80

650 100

650,500

750,500

400 400

  TABLE (cont'd) N of exem- Inten- Pressure- Result- Coefficient

  nitrogen, the state of

  Pa diffrac- test tion tion of the tion of the (number X-ray holding of holes on the

plans of o-

rientation

micro-

crystals

1 5 6 7 8

1.33.102 40 450 1.0

1!, 33.10-_21

2,66.10_2

6.65.10 '60 650 1.44

3.99.102 90 750 1.7

1.19 100 810 1.8

2,66_. - 350 -

3.99.101 30 450 1.0

3.99.10 80 700 1.6

3.99.101 90 750 1.7

3.99.10 100 800 1.8

2 1.33.10 2 40 410 1.8

6.65.102 60 500 2.08

1.19 90 800 3.3

1.33 100 1070 4.4

2,66 1 - 240 -

6.65.10-1 30 260 1.1

6.65.10 60 500 2.1

6.65.10-1 80 750 3.1

6.65.10_1 100 1070 4.4

6.65.10_1 100 800 3.3

6.65.10 85,580 2.4

Claims (3)

R E V E N D I C A T I 0 N S CLAIMS   1. - A cutting tool comprising a base (1) whose active surface (2) bears a wear-resistant coating (3) comprising microcrystals of a high-melting compound consisting of at least one metal and at least one at least one element of the group C, N, 0, B, characterized in that the greatest number of microcrystals of said high melting point compound consisting of at least one metal and at least one element of the group C, N, O, B, and further comprising Si, is oriented parallel to the surface   active (2) of the base (1) by the same crystallographic plane graph (4), (5).   2. - Tool according to claim 1, characterized in   what the crystallographic plane (4), (5) of   microcrystals has a superficial energy minimal.   3. - A method of manufacturing the cutting tool according to claim 1, consisting of evaporating and ionizing under vacuum at least one metal, heating the base (1) of the cutting tool and cleaning its active surface ( 2) by ion bombardment of at least one metal, then introducing into a vacuum a gaseous reactant and reacting at least one metal with at least one of its elements until a resistant coating is formed; wear (3)   consisting of their compound with a high melting point.   microcrystals, characterized in that the base (1) of the cutting tool is brought to a temperature of less than 100 C, at the temperature of its softening,   this heating temperature of the base (1) being   during the formation of the coating (3) in a range from this heating temperature to the   temperature of + 50 ° C, while at the same time   gaseous reactant in the range of 13.3 Pa to 1.33.102 Pa.