RU2464341C1 - Method for obtaining multi-layered coating for cutting tool - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: vacuum plasma application of multi-layer coating is performed. Lower layer of nitride or carbonitride of titanium, aluminium and silicon compound is applied at the following component ratio, wt %: titanium 87.7-91.9, aluminium 7.0-11.0, silicon 1.1-1.3. After that, intermediate layer of nitride or carbonitride of titanium, aluminium and silicon compound is applied at the following component ratio, wt %: titanium 93.7-94.9, aluminium 4.0-6.0, silicon 1.1-1.3. After that, upper layer of nitride or carbonitride of titanium and aluminium compound is applied at the following component ratio, wt %: titanium 91.5-94.5, and aluminium 5.5-8.5. Application of coating layers is performed with three cathodes horizontally located in one plane; the first and the second of the above cathodes are made from titanium and aluminium and located opposite each other, and the third cathode is made from titanium and silicon alloy and located between them; at that, lower layer is applied using the first and the third cathodes; intermediate layer is applied using the second and the third cathodes, and upper layer is applied using the first and the second cathodes.

EFFECT: improving operability of cutting tool.

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Description

The invention relates to methods for applying wear-resistant coatings to a cutting tool and can be used in metalworking.

There is a method of increasing the resistance of a cutting tool (RI), in which a wear-resistant coating (PI) of titanium nitride (TiN) or titanium carbonitride (TiCN) is applied on its surface using a vacuum-plasma method (see Tabakov V.P. Performance of a cutting tool with wear-resistant coatings based on complex nitrides and titanium carbonitrides. Ulyanovsk: UlSTU, 1998. 123 p.).

The reasons that impede the achievement of the technical result indicated below when using the known method include the fact that, in the known method, the applied coating does not provide the same high efficiency when a cutting tool is used with this coating under intermittent cutting conditions, in particular during milling, as during continuous cutting .

The closest method of the same purpose to the claimed invention in terms of features is the method of applying a multilayer coating, disclosed in the description of the patent for invention RU 2269605 C1, adopted as a prototype.

For reasons that impede the achievement of the technical result indicated below when using a known cutting tool with a coating adopted as a prototype, the multilayer coating in the known method has insufficient hardness and, therefore, crack resistance. As a result, the coating poorly resists the processes of wear and tear and quickly collapses when cutting.

Recently, the increase in the cost of metal-cutting tools and the tightening of requirements for precision machined parts made the problem of increasing the resistance of radiation sources even more urgent. One of the ways to increase the resistance and, as a consequence, the health of RI with a coating is to apply multilayer coatings with layers with different physical and mechanical properties. The presence in the coating of the upper layer with high hardness, helps to reduce the wear rate of radiation with multilayer coatings. To increase the adhesion strength of the coating to the tool base, it should include a lower layer with improved adhesive properties. In addition, an increase in the hardness of the lower coating layer also contributes to an additional decrease in the wear rate of radiation with multilayer coatings. Increasing the adhesion of the layers is achieved by applying an intermediate layer of elements of the upper and lower layers. This layer has a high chemical affinity with other layers, high hardness. The intermediate layer also contributes to increased crack resistance due to the appearance of additional boundaries between the layers.

The technical result is an increase in the health of RI.

The specified technical result in the implementation of the invention is achieved by applying a lower layer of nitride or carbonitride compounds of titanium, aluminum and silicon at their ratio, wt. %: titanium 87.7-91.9, aluminum 7.0-11.0, silicon 1.1-1.3; intermediate - from nitride or carbonitride compounds of titanium, aluminum and silicon at their ratio, wt. %: titanium 93.7-94.9, aluminum 4.0-6.0, silicon 1.1-1.3; the top - from nitride or carbonitride compounds of titanium and aluminum in their ratio, wt. %: titanium 91.5-94.5, aluminum 5.5-8.5, and the coating layers are applied horizontally located in the same plane by three cathodes, the first and second of which are made of titanium and aluminum and are located opposite to each other, and the third is made of an alloy of titanium and silicon and placed between them, with the lower layer being applied using the first and third cathodes, the intermediate layer using the second and third cathodes, the upper layer using the first and second cathodes.

This coating structure allows to obtain high adhesion to the base due to the presence in the coating of the lower layer having high adhesion to the tool base. Moreover, the layers have high hardness due to the additional alloying of the material of the coating layers and the presence in their structure of microlayers obtained by coating according to the proposed cathode arrangement.

The analysis of the prior art by the applicant, including a search by patents and scientific and technical sources of information, and the identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find sources characterized by features identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype, as the closest in the totality of the features of the analogue, allowed us to establish a set of significant distinguishing features in relation to the technical result perceived by the applicant in the claimed method set forth in the claims. Therefore, the claimed invention meets the condition of "novelty."

To verify the compliance of the claimed invention with the condition "inventive step", the applicant conducted an additional search for known solutions to identify signs that match the distinctive features of the claimed method of increasing the efficiency of RI, distinctive from the prototype. The search results showed that the claimed invention does not follow explicitly from the prior art for the specialist, since the influence of the transformations provided for by the essential features of the claimed invention on the achievement of the technical result is not revealed from the prior art determined by the applicant. In particular, the claimed invention does not provide for the following transformations:

- the addition of a known means by any known part, attached to it according to known rules, to achieve a technical result, in respect of which the effect of such an addition is established;

- replacement of any part of a known product with another known part to achieve a technical result, in respect of which the effect of such a replacement is established;

- the exclusion of any part of the funds with the simultaneous exclusion of the function due to its presence and the achievement of the usual result for such exclusion;

- an increase in the number of elements of the same type, actions to enhance the technical result, due to the presence in the tool of just such elements, actions;

- the implementation of a known tool or part of a known material to achieve a technical result due to the known properties of this material;

- the creation of a tool consisting of known parts, the choice of which and the relationship between them are based on known rules, recommendations, and the technical result achieved in this case is due only to the known properties of the parts of this tool and the relationships between them.

The described invention is not based on a change in a quantitative characteristic (s), the presentation of such signs in relationship or a change in its form. This refers to the case when the fact of the influence of each of these characteristics on the technical result is known, and new values of these signs or their relationship could be obtained on the basis of known dependencies and patterns. Therefore, the claimed invention meets the condition of "inventive step".

The invention consists in the following. During cutting, cracking processes occur in the coating, leading to its destruction. In addition, due to insufficient adhesion to the tool base and layers inside the multilayer coating, the latter can be destroyed as a result of adhesion-fatigue phenomena on the contact pads. Under these conditions, the coating should have a layered structure to inhibit cracks. The bottom layer of the coating must have high adhesion to the tool material. Coating layers must have high hardness to increase wear and crack resistance. Moreover, the layers of the multilayer coating should have high bond strength between each other, which is ensured by their high affinity for each other due to the presence of common elements.

Coated plates obtained with deviations from the indicated production technology showed lower results.

For experimental verification of the claimed method, a prototype coating was applied with a layer ratio corresponding to the optimal value specified in the known method, as well as a two-layer coating according to the proposed method.

The proposed coating is as follows. MK8 carbide inserts (4.7 × 12 × 12 mm in size) are washed in an ultrasonic bath, wiped with acetone, alcohol and mounted on a rotary device in the vacuum chamber of the Bulat-6 installation equipped with three cathodes located horizontally in the same plane. The first and second composite cathodes of titanium and aluminum located opposite each other are used, and the third cathode is made of an alloy of titanium and silicon located between them. The chamber is pumped out to a pressure of 6.65 · 10 ^-3 Pa, the rotator is turned on, a negative voltage of 1.1 kV is applied to it, one cathode is turned on, and at an arc current of 100 A, the plates are cleaned and heated to a temperature of 560-580 ° C. The focusing coil current is 0.4 A. Then at a negative voltage of 160 V, the coil current is 0.3 A and the reaction gas — nitrogen (or a mixture of nitrogen and acetylene) is supplied, the first (from titanium and aluminum) and the third (from titanium and silicon) cathodes and precipitate a lower coating layer of TiAlSiN (or TiAlSiCN) with a thickness of 2.0 μm. An intermediate coating layer of TiAlSiN (or TiAlSiCN) with a thickness of 2.0 μm is applied at a negative voltage of 160 V, a current of coils of 0.3 A and the second (from titanium and aluminum) and third (from titanium and silicon) cathodes and a supply of reaction gas - nitrogen (or a mixture of nitrogen and acetylene). The upper coating layer of TiAlN (or TiAlCN) with a thickness of 2.0 μm is applied at a negative voltage of 160 V, a current of 0.3 A coils included in the first (from titanium and aluminum) and second (from titanium and aluminum) cathodes and the supply of reaction gas is nitrogen (or a mixture of nitrogen and acetylene). Then shut off the evaporators, the supply of reaction gas, voltage and rotation of the device. After 15-20 minutes, the chamber is opened and the coated tool is removed.

The microhardness of the coatings was determined on a PMT-3 microhardness meter under a load of 100 g.

Durable tests of the cutting tool were carried out with symmetrical face milling of 5XNM steel blanks on a 6P12 machine. Tested carbide inserts grade MK8, processed according to the known and proposed methods. The cutting conditions were as follows: cutting speed V = 247 m / min, feed S = 0.4 mm / tooth, cutting depth t = 1.5 mm, milling width B = 20 mm. For the wear criterion, the value of the chamfer of wear along the rear surface h _z = 0.4 mm

Table 1 shows the test results of RI with the obtained coatings.

Table 1 Coated RI Test Results Coating material The chemical composition of the coating layers (ratio of metal components),% wt. Mikrotver
Dost, GPa Resistance, min Notes
nie 1 layer 2 layer 3 layer Ti Si Al Ti Si Al Ti Al TiN - 29.2 45 Analogue TiAlSi-TiAlSiN-TiSiN 89.8 1,2 9 93.8 1,2 5 93 1.2 * 37.6 251 Prototype TiAlSiN-TiAlSiN-TiAlN 91.8 1,2 7 94.8 1,2 four 94.5 5.5 39.0 286 89.9 1,1 9 93.9 1,1 5 93 7 39.3 294 89.8 1,2 9 93.8 1,2 5 93 7 39.5 301 89.7 1.3 9 93.7 1.3 5 93 7 39.2 296 87.8 1,2 eleven 92.8 1,2 6 91.5 8.5 38.7 284 TiAlSiCN-TiAlSiCN-TiAlCN 91.8 1,2 7 94.8 1,2 four 94.5 5.5 44.8 325 89.9 1,1 9 93.9 1,1 5 93 7 45.4 336 89.8 1,2 9 93.8 1,2 5 93 7 46.0 347 89.7 1.3 9 93.7 1.3 5 93 7 45.6 339 87.8 1,2 eleven 92.8 1,2 6 91.5 8.5 45.1 329 * - indicates the silicon content in the upper (third) coating layer

As can be seen from the data in table 1, the resistance of the wafers with the coatings deposited by the proposed method is higher than the resistance of the wafers with the coatings deposited by the prototype method by 1.13-1.38 times.

Thus, the above information indicates that when using the claimed method of obtaining a wear-resistant coating for RI the following set of conditions:

- a method for producing a multilayer coating for RI, embodying the claimed method in its implementation, is intended for use in industry, namely for applying wear-resistant coatings to RI, and can be used in metal processing;

- for the claimed method for producing a multilayer coating for RI in the form described in the independent clause of the claims, the possibility of its implementation using known means and methods prior to the priority date is confirmed;

- a method of obtaining a multilayer coating to obtain a wear-resistant coating for RI, embodying the claimed method in its implementation, is capable of achieving the achievement of the technical result perceived by the applicant.

Therefore, the claimed invention meets the condition of "industrial applicability".

Claims (1)

A method of obtaining a multilayer coating for a cutting tool, including vacuum-plasma deposition of a multilayer coating, characterized in that a lower layer of nitride or carbonitride of a compound of titanium, aluminum and silicon is applied at their ratio, wt.%: Titanium 87.7-91.9, aluminum 7.0-11.0, silicon 1.1-1.3, intermediate - nitride or carbonitride compounds of titanium, aluminum and silicon at their ratio, wt.%: titanium 93.7-94.9, aluminum 4, 0-6.0, silicon 1.1-1.3, the upper - from nitride or carbonitride compounds of titanium and aluminum in their ratio, wt. %: titanium 91.5-94.5, aluminum 5.5-8.5, and the coating layers are applied horizontally located in the same plane by three cathodes, the first and second of which are made of titanium and aluminum and are located opposite to each other, and the third is made of an alloy of titanium and silicon and placed between them, with the lower layer being applied using the first and third cathodes, the intermediate layer using the second and third cathodes, the upper layer using the first and second cathodes.