RU2690265C1 - Method of producing multicomponent coatings from nonferrous metals - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely, to production of coatings from alloys of nonferrous metals by fusion. Method of producing multicomponent coatings from non-ferrous metals includes remelting of initial metal materials on substrate by electric arc with non-consumable tungsten electrode in atmosphere of inert gas, wherein initial metal materials are used in the form of blanks of twisted wires, pack of plates or mixture of powders prepared from Al, Ti, Ni, Cr, Fe, Mo, Mn, Cu, Zn, W, Nb, Zr, Ta or their alloys, and remelting is carried out in pulsed mode, providing dynamic mode of electric arc burning, with amplitude of current pulses of 100–400 A, pulse duration of 20–500 mcs, pulse repetition frequency of 200–5,000 Hz, duty current at interval between pulses of 12–50 A, at substrate displacement relative to electrode.

EFFECT: invention is aimed at obtaining coatings from multicomponent alloys based on 5 or more elements with a variation of elemental and concentration composition.

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Description

The invention relates to metallurgy, namely, to obtain multi-component coatings with a wide variation of the elemental composition, including the elements Al, Ti, Ni, Cr, Fe, Mo, Mn, Cu, Zn, W, Nb, Zr, Ta or their alloys and can be used in metallurgy, electrical, automotive and aviation industries.

A method of obtaining multicomponent coatings of the Al-Cr-Si-Ti-Cu-N system by the method of ion-plasma synthesis (Korotaev A.D., Ditenberg I.A., Berezovskaya V.R., Denisov K.I., Pinzhin U. P., Borisov DP. Influence of ion-plasma synthesis modes on the features of the structural-phase state of multicomponent nanocomposite coatings of the Al-Cr-Si-Ti-Cu-N system // Izvestiya Vuzov. Fizika. - 2014. - T. 57. - № 10. - p. 3-9.), Which allows to obtain films several micrometers thick.

However, the known method is technologically difficult and for its implementation requires the purity of the sample surface and vacuum.

The closest to the technical essence of the solution, selected as a prototype, is a method for producing multicomponent alloys (Firstov, SA, Gorban, VF, Krapivka, NA, Pechkovsky, EP, Danilenko, NI, Karpets, M Mechanical properties of cast multicomponent alloys at high temperatures // Modern Problems of Physical Materials Science, 2009. Issue 18. P. 140-147), which consists in melting by electric arc method with non-consumable tungsten electrode in an atmosphere of purified argon on a water-cooled copper hearth further it is repeatedly re-melted with pouring into either a copper water-cooled mold (V _ohl ≈ 800–900 K / s) or directly to the hearth (V _ohl ≈ 3000 K / s). The latter is necessary for the formation of a large number of crystallization centers in a liquid solution, that is, to create an ultrafine-grained alloy structure in the solid state - as an additional factor for achieving high strength.

For the implementation of this method requires multiple remelting followed by rapid cooling, which requires the use of special equipment and significant energy consumption.

The technical result of the proposed invention is to develop a method for producing multicomponent (based on 5 or more elements) surfacing and coatings with a variation of the elemental and concentration composition.

The method of obtaining multicomponent coatings from non-ferrous metals, as well as in the prototype, involves remelting the original metallic materials on a substrate by an electric arc with a non-consumable tungsten electrode in an inert gas atmosphere.

According to the invention, the source metal materials are used in the form of blanks from twisted wires, a package of plates or a mixture of powders prepared from Al, Ti, Ni, Cr, Fe, Mo, Mn, Cu, Zn, W, Nb, Zr, Ta or their alloys, and remelting is carried out in a pulsed mode, providing a dynamic mode of electric arc, with an amplitude of current pulses of 100-400 A, a pulse duration of 20-500 μs, a pulse repetition rate of 200-5000 Hz, a standby current in the interval between pulses of 12-50 A, with moving the substrate with respect to the electrode.

Due to the concentrated metered heat flow of the electric arc, a small volume of material is melted during a plasma pulse (cathode jet) and subsequent layered crystallization occurs. The gas-dynamic impact of the plasma promotes the mixing of the material components in the liquid state, and the subsequent pause between pulses promotes rapid crystallization and fixation of the uniform distribution of the components.

Using the specified pulse mode provides high-quality mixing of the melt components. In particular, the melting of chromium in a thin-walled copper tube yielded a structural state with a uniform distribution of copper in the sample (Fig. 1).

FIG. 1 shows an example of mixing in the Cr-Cu system. White streaks are copper precipitates forming at the borders.

FIG. 2 shows an example of the installation scheme for the implementation of the proposed method.

FIG. 3 shows a bundle of Al, Ti, Cu, Ni-Cr, Fe, Mo wires.

FIG. 4 shows an electron microscopic image of the melting of the Fe-Cr-Mo-Ti-Ni-Cu-Al system on a substrate.

Table 1 shows the values of microhardness (Hμ, GPa) at various distances from the surface of the smelting.

The proposed method is implemented using the installation (Fig. 2), which contains a base 1, on the guides of which a table 2 is installed, which is connected through the appropriate spindle with an electric drive of vertical movement 3 and with an electric drive of horizontal movement 4. Electric drives 3 and 4 are connected to a numerical system software control 5 (CNC), which is associated with a device for the formation of current pulses 6 (UFIT). As a device for the formation of current pulses 6 (UFIT) used a device for the formation of pulses by welding current [RU 2343051 C1, publ. January 10, 2009]. The substrate 7 with the melted material 8 is fixed on the table 2. A substrate of the molten material 9 (UPVM) is placed above the substrate 7, which is attached to the fixed base 1. The device for feeding the melted material 9 (UPVM), depending on the type of material, can be a mechanism wire feed, magazine boot device or vibratory hopper boot device. The drive 10, which is connected to the numerical control system 5 (CNC), is connected to the device for feeding the raw material 9 (UPVM). Above the investment material 8 is placed a non-consumable tungsten electrode 11 attached to the base 1, on which a nozzle 12 is fitted. The upper part of the nozzle 12 is connected by a pipe 13 through an inert gas supply device 14 (URI) connected to numerical control system 5 (CNC) with a balloon for inert gas 15 (BIT). Tungsten electrode 11 is connected to a device for the formation of current pulses 6 (UFIT), which is connected to the substrate 7.

The raw materials for the prefabricated blanks can be in the form of powders, wires or plates of both pure metals and various alloys. Wire samples are compacted by twisting them into a bundle. Powder materials can be compacted in various ways: by packing into thin metal foil or into a thin-walled tube, consolidating by pressing, self-propagating high-temperature synthesis, spark plasma sintering, gluing. The substrate 7 for placing the source material can be made of different metals and alloys.

Moving the table 2 in the vertical and horizontal planes using electric actuators 3 and 4, controlled from the numerical control system 5 (CNC), established a gap between the electrode 11 and the initial melted material 8 within 1-2 mm and excited the arc (for example, short-term closure this gap with a carbon electrode). At the same time, from the numerical control system 5 (CNC), commands were sent to a device for generating current pulses 6 (UFIT), a drive 10 for operating the device for feeding material 9 (UPVM) and electric drives 3 and 4, providing movement of the table 2.

The melted material 8 or served from the feeder melted material 9 (UPVM), made in the form of coils with wire or magazine boot device driven by the actuator 10, the rotation speed of which is consistent with the speed of movement of the table 2, or placed directly on the substrate 7. Refining is carried out by an electric arc with a non-consumable tungsten electrode 11 in a protective environment of inert gas, which is fed into the nozzle 12 with a given flow rate, while the protective atmosphere is provided by continuous supply of inert gas to the area of formation of the arc. The power of the arc carry pulses of welding current from the device for the formation of current pulses 6 (UFIT). The arc power modes: amplitude, pulse duration, frequency, and table speed 2 are set by the numerical control system 5 (NC) according to a given program.

In the process of obtaining surfacing, pulsed mode is used, which ensures the dynamic nature of the arc. The arc is powered by pulses of welding current with an amplitude in the range from 100 to 400 A, a pulse duration from 20 to 500 microseconds and a frequency from 200 to 5000 Hz. Between pulses, an arc on duty in the range from 12 to 50 A is lit. Sequential remelting with overlapping of the molten baths is ensured by the horizontal movement of the table 2 with the workpiece 8.

Example 1

From wires of metals and alloys Al (purity 99.9), Ti (purity 99.9), Cu (purity 99.9), Ni-Cr (75% Ni - 25% Cr), Fe (purity 99.8), Mo (purity 99.9) with a different cross section (from 0.2 mm to 1 mm) was twisted with a rope (Fig. 3). Getting the surfacing was carried out on a steel substrate 7, in an argon environment. A pulsed mode was implemented to ensure the dynamic nature of the arc: the pulse amplitude was 350 A, the duration was 70 microseconds, the frequency was 2000 Hz, the standby arc was 25 A.

FIG. 4 asterisks 17, 18, 19 indicate the areas of microhardness measurement of the formed surfacing 20 at different distances from its surface. As can be seen from Table 1, the microhardness values of the surfacing in the region 19 (near the boundary 21 of the surfacing and the substrate) exceed Hμ of the substrate 7 by 4.7 times, and near the surface (region 17) its values are greater by ~ 5.2 times.

The lenticular shape of the fusion-substrate interface 21, determined by the geometric dimensions of the molten bath, also indicates intense mixing of the formed fusion with the substrate 7. As a result of the bend test at room temperature, no detachment or cracking of the formed fusion from the substrate was detected, which indicates high adhesive strength.

The resulting coating, on the one hand, provides a highly reliable connection with a less durable substrate, on the other hand, it allows the formation of high-strength states in the surface layers exposed to the strongest external effects in practical use.

It is important to note that heat-resistant high-alloy steels (of type EI680) that are close in elemental composition are characterized by a microhardness of ~ 1.8 GPa, which is almost 4 times lower than the microhardness of the obtained surfacing.

Example 2

From the plates Al (purity 99.9), Ti (purity 99.9), Ni (purity 99.9), steel type 40G (Fe-Mn-0.4 C), brass L63 (Cu-37 Zn) with a thickness of 0, 2 mm to 0.8 mm collected package. The melting was carried out in argon on a copper substrate. The following parameters were implemented: pulse amplitude - 400 A, duration - 500 microseconds, frequency - 5000 Hz, duty arc - 50 A. Microhardness of the surface layer of the coating obtained was 7.1 GPa.

Example 3

A mixture of powders (W, Nb, Mo, Cr, Zr, Ti, Ta) was packed into a thin-walled copper tube. The melting was carried out in helium medium on a steel substrate, according to the proposed mode with parameters: pulse amplitude - 100 A, duration - 20 microseconds, frequency - 200 Hz, pilot arc - 12 A. Microhardness of the surface layer of the coating obtained was 8.3 GPa.

Thus, the proposed method can be used to obtain surfacing from multicomponent alloys, which allow the formation of coatings of various thickness, significantly exceeding the characteristics of the substrate in terms of strength properties.

Claims (1)

A method of producing multicomponent coatings from non-ferrous metals, including remelting the source metal materials on a substrate with an electric arc with a non-consumable tungsten electrode in an inert gas atmosphere, characterized in that the source metal materials are used in the form of blanks from twisted wires, a package of plates or a mixture of powders made from Al , Ti, Ni, Cr, Fe, Mo, Mn, Cu, Zn, W, Nb, Zr, Ta or their alloys, and remelting is carried out in a pulsed mode, providing a dynamic mode of electric arc, with ampl It has a current pulse of 100-400 A, a pulse duration of 20-500 μs, a pulse repetition rate of 200-5000 Hz, a standby current in the interval between pulses of 12-50 A, when the substrate moves relative to the electrode.

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