RU2561577C2 - Method of producing wear resistant coating for cutting tool - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: proposed process comprises vacuum-plasma spraying of sandwiched coating. Applied is lower layer of titanium, aluminium, silicon, niobium and molybdenum nitrides at the following ratio of components in wt %: titanium - 63.56, aluminium - 10.11, silicon - 0.94, niobium - 21.47, molybdenum - 3.92. Application is executed by three cathodes arranged horizontally in one plane. First cathode are made of titanium and silicon alloy and arranged in opposition, second cathode is made of titanium and aluminium and arranged opposite the first one while third cathode is made of molybdenum and niobium and arranged there between.

EFFECT: higher cutting efficiency.

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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 and silicon nitride (TiSiN) is applied on its surface using a vacuum-plasma method (see Chikhranov A.V. Improving the operability of a cutting tool by developing and using multi-element wear-resistant coatings based on modified titanium nitride: Diss. ... Ph.D. in Engineering Sciences: 05.03.01, 2006. - 314 p.). The reasons that impede the achievement of the following technical result when using the known method include the fact that in the known method, the coatings have a relatively low hardness. As a result of this, the coating undergoes more wear and tear, cracks quickly nucleate and propagate in it, leading to the destruction of the coating, which reduces the resistance of the coated radiation.

The closest method of the same purpose to the claimed invention in terms of features is a method of applying a wear-resistant coating of titanium nitride, silicon and aluminum TiSiAlN (see Chikhranov A.V. Improving the performance of a cutting tool by developing and using multi-element wear-resistant coatings based on modified titanium nitride: Diss. ... Candidate of Technical Sciences: 05.03.01, 2006. - 314 p.), adopted as a prototype.

The reasons that impede the achievement of the technical result indicated below when using a known cutting tool with a coating adopted as a prototype include the fact that in the known method, the wear-resistant coating 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 durability and, as a consequence, the performance of RI coated is to coat with high hardness, crack and wear resistance. Such an effect can be achieved by targeted doping and by creating a micro-layer of the coating during its deposition.

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 wear-resistant coating of nitride or carbonitride of titanium, aluminum, silicon, niobium and molybdenum at their ratio, wt.%: Titanium 63.56, aluminum 10.11, silicon 0.94, niobium 21.47, molybdenum 3.92, and the coating is carried out horizontally located in the same plane by three cathodes, the first of which is made of an alloy of titanium and silicon, the second is made of an alloy of titanium and aluminum and is opposite to the first, and the third is made of niobium I and molybdenum and have between them.

This arrangement of the cathodes makes it possible to obtain the largest number of microlayers in the coating during coating deposition with good adhesion between them and their maximum hardening due to the mutual doping with elements from different cathodes.

The invention consists in the following. During cutting, cracking processes occur in the coating, leading to its destruction. Under these conditions, the coating should have a layered structure to inhibit cracks. The coating should have high hardness to increase wear and crack resistance.

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, as well as wear-resistant coatings according to the proposed method.

The application of the proposed coatings 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. When applying the coating, the first cathode is used, made of an alloy of titanium and silicon, the second is made of an alloy of titanium and aluminum and is opposite to the first, and the third is made of niobium and molybdenum and placed 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, the cathode is made of an alloy of titanium and silicon, 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, with a negative voltage of 160 V, a coil current of 0.3 A and a supply of reaction gas (nitrogen for applying nitride coatings or 70% nitrogen and 30% acetylene for applying carbonitride coatings), all three cathodes are turned on and deposited wear-resistant coating TiAlSiNbMoN or TiAlSiNbMoCN 6 μm thick. 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 the longitudinal turning of blanks made of 30KhGSA steel on a 16K20 lathe. Cutting modes: cutting speed V = 160 m / min, feed S = 0.3 mm / rev, cutting depth t = 1.0 mm, processing was performed without the use of coolant. Tested carbide inserts grade MK8, processed according to the known and proposed methods. The wear criterion was a chamfer of wear along the back surface with a width of 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 (ratio of metal components), wt.% Microhardness, GPa Resistance, min Note Ti Si Al Nb Me * one 2 3 four 5 6 7 8 9 TiSiN 98.75 1.25 - - - 36.5 34 Analogue TiSiAlN 82.75 1.25 16,0 - - 43.1 64 Prototype TiAlSiNbMoN 63.56 0.94 10.11 21.47 3.92 46.7 81 TiAlSiNbMoCN 63.56 0.94 10.11 21.47 3.92 49.9 88

As can be seen from the data in table 1, the resistance of the plates with the coatings deposited by the proposed method is higher than the resistance of the plates with the coating deposited by the prototype method by 1.26-1.38 times.

Claims (1)

A method of obtaining a wear-resistant coating for a cutting tool, including vacuum-plasma coating, characterized in that a coating is made of a nitride or carbonitride of a compound of titanium, aluminum, silicon, niobium, molybdenum in their ratio, wt.%: Titanium - 63.56, aluminum - 10.11, silicon - 0.94, niobium - 21.47, molybdenum - 3.92, and the coating is carried out horizontally in the same plane by three cathodes, while the first cathode is made from an alloy of titanium and silicon, the second from an alloy titanium - aluminum and position opposite to the first, and the third is made composite of niobium and molybdenum and placed between them.