RU2792246C1 - Method and system of consumable electrode plasma welding - Google Patents

Abstract

FIELD: welding; surfacing of metals.

SUBSTANCE: invention can be used for restoration of worn parts by finishing surfacing without subsequent mechanical treatment, thin layers growth by surfacing. The electrode wire 7 is fed along the axis of the plasma welding system from top to bottom to the product 4. Between the consumable electrode 7 and the product 4, an arc 8 burns, surrounded by an axial plasma arc 3 formed by a connection of at least two inclined plasma arcs 1. Inclined plasma arcs 1 are directed to an axial point on the axis of the system above the product 4 with the possibility of forming an axial plasma arc 3 or are directed with an offset from the axial point and the axis of the system with the possibility of forming and rotating around the axis of the system of an axial plasma arc, while the plasma arcs 1 are directed and connected at a point on the axis of the system above the product 4. The plasma welding system includes a housing 15 with holes. A burner 5 for consumable electrode welding 7 is installed in the axial hole 16 of the body. In the side inclined holes 17, plasma-forming nozzles of plasma torches 2 are installed. The axes of the plasma nozzles are directed to a point on the axis of the system at a given distance B from the lower surface of the housing. Surfacing with rotation of a consumable electrode does not result in heating of the base metal of the product and allows using the method for finishing surfacing and growing parts.

EFFECT: fast local heating of metal and deposition of molten metal of a consumable electrode without splashing while increasing the penetration depth.

3 cl, 13 dwg

Description

The invention relates to welding of metals and can be widely used in mechanical engineering and other industries for:

- welding of metals;

- surfacing of metals with high productivity with minimal penetration and mixing with the base metal, with a large control of the thickness of the deposited layer when using electrode wire of large diameter, and the minimum;

- repair of worn parts (renovation) with finishing welding without subsequent machining, or with minimal processing - grinding;

- growing parts (3D - printing) of large-sized - rocket bodies or, when using microplasma torches, - small parts.

A known method of consumable electrode plasma welding (PSPE) - patent No. 7104337 Netherlands from 04/01/1971 MKI V23K 9/00, 9/16. In this method, the consumable electrode (wire) passes along the burner axis from top to bottom through the current-carrying mouthpiece coaxial with the burner axis and the plasma-forming nozzle of the plasma torch, while an axial plasma arc also passes through the plasma-forming nozzle, which is maintained between the tungsten electrode located on the side and the product. The plasma-forming gas is supplied inside the plasma-forming nozzle, and the shielding gas is supplied outside. The plasma arc is powered by the plasma power supply. At a distance from the current-carrying mouthpiece (wire extension), the consumable electrode (PE) arc burns, which is maintained from the power source of the PE arc. The plasma arc surrounds the PE arc and part of the PE take-off - the PE take-off in the plasma. The PE arc and the plasma arc must have the same polarity: direct - minus on the electrode, plus on the product or reverse - plus on the electrode, minus on the product.

Compared to the consumable electrode welding (CWE) method, in which one PE arc burns in a protective gas, the SSPE method has the following advantages:

- regulation of heat input into the workpiece to be welded and consumable wire is ensured at a high deposition rate;

- the PE arc is excited without touching the product and splashing;

- stable small-drop transfer without splashing is provided;

- when the PE arc current increases and the critical value is reached, the wire under the pressure of the arc, heated by the plasma and the current passing through it becomes plastic, bends in the transverse direction and, under the influence of electromagnetic force, rotates together with the arc and a fan of drops over the surface of the product, while the critical current of rotation PE is less than with SPE, where there is no plasma, [Plasma consumable electrode welding. Translation from Japanese No. Ts-86808 of an article from the magazine "Yosetsu Gijutsu", 1975, v.23, No. 3, p. 85-90. All-Union Translation Center NTLD, Moscow, 1976].

The rotation mode makes it possible to reduce and ensure the uniformity of penetration of the base metal and increase the width of the deposit.

Despite the advantages, the SSPE method has significant disadvantages.

The instability of the plasma arc, which occurs for several reasons:

- plasma breakdowns on the wire and the plasma nozzle, which is destroyed [A.V. Petrov. Plasma welding. "VINITI. Results of science and technology. Welding series. T 12". Moscow, 1980, p. 53-109], while the probability of breakdown on the wire is greater, since the protrusion of the PE in the plasma is greater than the length of the plasma nozzle;

- low plasma stability (extinguishes) with a large diameter plasma nozzle, which is required to prevent breakdowns [W.G. Essers, G.A.M. Willems, J.J.C. Buelens and M.R.M. van Gompel. Plasma-MIG welding - a new torch and arc starting method. "Metal Construction", No. 1, 1981, s. 36-42];

- with welding disturbances: wire bends, individual splashes and at low PE arc current, [Schevers A.A. Plasma-MIG welding of Aluminium. "Welding and Metall Fabrication", vol. 44, no. 1, 1976.].

Lower thermal efficiency of SSPE in comparison with SPES. With PSPE, the dimensions of the common heat source are larger, and its concentration is smaller and, as a result, the penetration depth is smaller. The plasma arc during SSPE surrounds the PE arc (PES), in addition, it itself is much larger than a conventional plasma arc. So the diameter of the plasma-forming nozzle for PSPE is 8-10 mm, and for conventional plasma welding it is not more than 5 mm.

With PSPE, there are limitations on the current of the PE arc. A large wire overhang requires an increase in its diameter in order to increase rigidity. Larger diameters require more arc current. To ensure the rotation mode of the arc for steel wire ∅1.2 mm with a reach of 40 mm, a large arc current is required - 300A, while the rotation mode is limited by the current, in which the rotating jet is accompanied by spraying of metal on the sides of the roller and in the arc gap, [Plasma consumable welding electrode. Translation from Japanese No. Ts-86808 of an article from the magazine "Yosetsu Gijutsu", 1975, v.23, No. 3, p. 85-90. All-Union Translation Center NTLD, Moscow, 1976].

Tungsten electrode PVD devices are not suitable for reverse polarity welding due to the limited durability of the tungsten electrode. So for direct polarity, when the resistance of the tungsten electrode in the protective gas argon is high (for an electrode ∅ 3 mm, the current is 200-300A), but unsatisfactory - for the reverse (for an electrode ∅ 3 mm, the current is 20-40A). For reverse polarity, it is possible to use a tungsten electrode ∅ 6 mm current 80-130A, which is also not enough (data on the products of JSC "Spetselektrod", Moscow, were used). Meanwhile, the welding of aluminum and magnesium alloys must be carried out in reverse polarity so that the oxide film on the surface of the edges to be welded is broken due to the cathode sputtering effect. Therefore, in the case of aluminum PSPE at reverse polarity, copper tubular (the wire passes inside the tube) water-cooled electrodes are used, [USSR author's certificate 997348 of 05/27/1981], or copper tubular with ring graphite inserts, [USSR author's certificate 1123181 of 10/28/1983]. It should be noted that the resource of copper electrodes and electrodes with graphite inserts is small.

Thus, SSPE has many disadvantages, but all of them are related to the fact that the electrode wire passes through the plasma nozzle, which causes: plasma instability, large plasma sizes and low heat source density, limited mode and application range.

In contrast to the supply of electrode wire through the nozzle of a plasma torch, the process of arc-plasma welding was studied, in which the plasma arc was directed to the PE and the arc on it from the side, [Barashkov A.S., Tkachuk K.K. Reduction of spatter by the effect of the arc on metal transfer in consumable electrode welding. // Welding production, No. 9, 1986, p. 13-14]. In this work, it was shown that when the polarities of the plasma arc and the PE arc are connected according to the SSPE scheme, the side plasma arc blows off the droplets formed on the wire and disrupts the metal transfer.

A two-jet plasma torch is known, in which the inclined cathode and anode jets, symmetrical about the axis of the system, are combined into an axial jet, into which powder is supplied for spraying, [Novikov O.Ya., Tamkivi P.I., Timoshevsky A.N. etc. Multi-arc systems. / Novosibirsk: Nauka SO RAN, 1988, p. 55-57], [US Patent 3472995]. This diagram cannot be used for SSPE, but the diagram shows that an axial plasma arc can be created by connecting inclined plasma arcs, and a consumable electrode can be fed into the axial plasma arc, excluding the supply through the plasma nozzle.

Known multi-arc (MD) plasma torch, which is characterized by the presence of more than two inclined plasma arcs, evenly spaced relative to the common axis of the system, and the plasma arcs form a common flow [Novikov O.Ya., Tamkivi P.I., Timoshevsky A.N. etc. Multi-arc systems. / Novosibirsk: Nauka SO RAN, 1988, p. 57-58], [UK Patent 959472]. This plasma torch is used for spraying refractory materials and is a prototype.

In an MD plasma torch, inclined plasma arcs from anode plasma torches (reverse polarity) are directed to one point on the axis of the system from the edge, but inside the nozzle - the cathode. A bar of refractory material is fed to the same point along the axis of the MD plasma torch. From the nozzle-cathode, a common plasma stream with the sputtered material is blown out. If inclined plasma arcs are directed to a point of the axis of the system with a slight displacement, then a vortex motion of the total plasma flow occurs. The disadvantage of the MD plasma torch is that it does not have an axial plasma arc, since the inclined plasma arcs are connected at a point inside the nozzle - cathode into one arc, which immediately passes to the nozzle - cathode. This disadvantage can be eliminated if the nozzle - cathode is replaced by a cathode - product. The connection point must be in front of the product, then from the arc connection point to the product, an axial plasma arc will burn, into which a consumable electrode can already be fed instead of a rod.

The problem to be solved by the invention is the exclusion of the supply of electrode wire through the plasma-forming nozzle during PSPE and the elimination of the disadvantages associated with this supply, namely:

- the large diameter of the plasma nozzle reduces the concentration of the heat source, the depth of penetration, as well as the stability of the plasma arc;

- a large reach of the consumable electrode in the plasma increases the probability of plasma breakdown;

- a large reach of the consumable electrode makes it difficult to weld using a small wire diameter;

- there is a limited range of mode and application.

The problem is solved by the consumable electrode plasma welding method, in which the consumable electrode is fed along the axis of the system from top to bottom to the product, while an arc burns between the consumable electrode and the product, surrounded by an axial plasma arc that also burns on the product. According to the invention, an axial plasma arc is formed by connecting two or more inclined and evenly spaced plasma arcs relative to the axis of the system, while the plasma arcs are directed and connected at a point on the axis of the system above the product.

It is possible to implement a method in which inclined plasma arcs are directed to a point on the axis of the system with a displacement and rotate the axial plasma arc, which ensures uniform distribution of the axial plasma arc around the circumference, while heating the PE will increase and the transition to the PE rotation mode will accelerate.

A method is also possible in which the consumable electrode is simultaneously rotated relative to the axis of the system while being fed, which ensures uniform penetration of the product.

In addition, the method is implemented using a consumable electrode plasma welding torch, which, according to the invention, has a body with holes, while the axial hole is designed to install a consumable electrode torch, and two or more lateral inclined holes, evenly spaced relative to the body axis, are designed for the installation of plasma torches, while the axes of the side holes are directed to a point on the body axis.

Comparison of the proposed technical solution - multi-arc consumable electrode plasma welding with the state of the art in scientific and technical literature and patent sources shows that the totality of the essential features of the claimed solution was not known. Therefore, it meets the condition of patentability - "novelty".

The claimed solution can be industrially applicable, as it can be manufactured industrially, feasible and reproducible, therefore, it meets the condition of patentability - "industrial applicability".

Distinctive features of the proposed technical solution are:

- axial plasma arc is formed by the connection of two or more inclined and evenly spaced relative to the axis of the plasma arc system;

- plasma arcs are directed and connected into an axial arc at a point on the axis of the system above the product.

The influence of distinctive features on the solution of the problem:

- the stability of plasma arcs does not depend on the consumable electrode and is determined by the high stability of conventional plasma torches;

- adjustment of the height of the axial plasma arc makes it possible to control the outreach of the wire in the plasma, at which the breakdown of the plasma onto the wire occurs;

- since each plasma arc is compressed, the axial plasma arc also remains compressed, so the concentration of the heat source is close to the concentration of the heat source in the SPE;

- wire stick-out is a common stick-out at CPE and the process is provided in a wide range of regimes;

- an increase in the height of the compressed axial plasma arc provides accelerated heating and rotation of the consumable electrode;

- multi-arc plasma system provides reverse polarity welding, as it reduces the thermal load on a separate tungsten electrode.

The proposed torch for plasma welding provides the implementation of the patented method.

The proposed technical solution is illustrated by drawings in the figures: in Fig. 1 shows a diagram of the method and torch of multi-arc plasma welding with a consumable electrode (MPWMA), in Fig. 2 - section A-A of Fig. 1 in FIG. 3 - section B-B of Fig. 2 in FIG. 4 - method and burner 2DPSPE with a specific study, in Fig. 5 is a section B-B of FIG. 4 in FIG. 6 - burner body 2DPSPE, in Fig. 7 - section Г-Г of FIG. 6, in FIG. 8 - section D-D of FIG. 7 in FIG. 9 - design of a small-sized plasma torch MDPSPE, in Fig. 10 is a section E-E of FIG. 9, in FIG. 11 - section F-G of FIG. 9, in FIG. 12 is a section 3-3 of FIG. 11, in FIG. 13 - external view of the assembly of a tungsten electrode with a swirler.

In FIG. 1-2 shows a diagram of an MDSPE with four plasma arcs. The term "Multi-arc plasma torch" involves the use of more than two arcs, that is, three or more, [Novikov O.Ya., Tamkivi P.I., Timoshevsky A.N. etc. Multi-arc systems. / Novosibirsk: Nauka SO RAN, 1988, p. 57]. However, in our case, it is possible to use two plasma arcs, which will reduce the dimensions of the MD burner in the transverse direction and provide surfacing in cramped conditions, for example, when surfacing worn ridges of railroad wheels, which can be combined with hardening, [Barashkov A.S. Plasma hardening of ridges of tires of wheel pairs. The experience of the Taganay locomotive depot (Zlatoust) // Lokomotiv, 2019, No. 8, p. 31-34]. In fact, with two plasma arcs, the third PE arc will burn, therefore, the method and device of MDPSPE involves the use of two or more plasma arcs. When describing a specific method of MDPSPE with a known number of plasma arcs, instead of the letter M, the number of plasma arcs should be put. For example, the methods 2DFSPE and 4DFSPE mean two-arc and four-arc ESPE.

Inclined at an angle β plasma arcs 1 from the plasma torches 2 are evenly spaced relative to the axis of the system. The angle of inclination β should be minimal in order to increase the heating efficiency of the product, reduce the length of the arcs and the power of the plasma torches, and also reduce the size of the burner. Inclined plasma arcs are connected at a point above the product on the axis of the system into an axial plasma arc 3, burning on the product 4. From above along the axis of the system, a consumable electrode - wire 7 is fed into the axial plasma arc through the burner 5 (SPE torch) with a current-carrying mouthpiece 6. Between the PE and the product, an arc 8 burns, inside which there is a jet of drops 9 from the PE to the product. All plasma arcs and the PE arc must have the same polarity: forward or reverse. Since arcs of the same polarity are attracted, the axial plasma arc is always located around the PE and is displaced following the displacement of the PE. Each plasma arc burns from a separate plasma power source 10. The PE arc burns from a power source 11. Protective gas 13 is supplied through the protective nozzle 12 of the SPE burner. Plasma gas 14 is supplied to the plasma torches.

The basis of the design of the burner MDPSPE (MD burner) is the body 15 with holes. To the axial hole 16, the protective nozzle of the SPE burner is fixed, and the plasma nozzles 18 of the plasma torches are installed in the side, inclined and evenly spaced holes 17 to the body axis, as is done in [Novikov O.Ya., Tamkivi P.I., Timoshevsky A. N. etc. Multi-arc systems. / Novosibirsk: Nauka SO RAN, 1988, p. 54-55], where for parallel plasma arcs, plasma-forming holes are made in one housing. The axes of the side holes 17 are directed to a point on the body axis. In the places of installation of plasma nozzles in the body there are threaded holes for fastening plasma torches. The body of the MD burner also has holes for installing tubes of 19 laser rangefinders for monitoring the thickness of the deposited metal layer, a pyrometer for controlling the heating temperature of the product and for supplying powder in order to impart increased hardness, wear resistance, impact resistance and other physical and technical properties to the deposited metal. At the bottom of the case there is a water cooling circuit 20.

The scheme of multi-arc welding is effective with reverse polarity, when the resistance of the tungsten electrodes 21 in plasma torches is limited. For two plasma arcs of reverse polarity with a tungsten electrode diameter of 6 mm, the total current will be 160-260A, which is quite enough, and for 4 arcs - 320-520A, which is a lot and the current on each arc must be reduced.

If inclined plasma arcs are directed to a point of the axis of the system with a small (within the diameter of the axial arc) displacement e, then the rotation of the axial plasma arc will occur, Fig.3, which will ensure uniform distribution of the axial plasma arc around the circumference. In this case, the PE heating will increase and the transition to the PE rotation mode will accelerate.

According to the scheme, inclined plasma arcs are connected into an axial plasma arc at a point on the axis of the MD burner at a distance B from the lower surface of the burner. The height of the axial plasma arc H _P =Δ-B, where: Δ is the air gap between the MD burner and the product; B - output of inclined plasma arcs from the MD burner. Thus, the height of the axial plasma arc of the NP can be controlled by changing the air gap Δ. To ensure stable small-droplet transfer, the height of the axial plasma arc must be no less than the length of the SPE arc N _P ≥ L _D . In this case, the wire projection in the plasma L _P should not exceed the critical value when the plasma breakdown occurs on the wire, L _P =N _P -L _D ≤ U _PP / E _P , where: E _P - electric field strength in the plasma, V / mm; U _PP - voltage drop at the point of plasma breakdown on the wire, V (one breakdown point is enough, since the arc on the wire is already on).

It should be noted that in the case of MDPSPE, compared to SSPE, the axial plasma arc is compressed with a high strength E _P , since it is formed by compressed inclined plasma arcs. With a compressed arc, the efficiency of heating the product and the wire increases, but the breakdown of the plasma on the wire does not occur, since the stick-out of the wire in the plasma L _P is small and can be adjusted from zero when N _P \u003d L _D .

In FIG. 1, the wire in its overhang LB is shown to be curved with an offset from the axis of the MD burner R. This is the remaining natural curvature after winding the wire on a spool. The curvature of the wire ensures constant contact in the current-carrying mouthpiece. If the wire is completely straightened by the bending rollers, then the contact may be lost, the arc excited and the wire will fuse to the mouthpiece. A known method of consumable electrode welding [USSR Patent 1807922 dated May 5, 1991], in which the displacement of the end of the wire R is calculated from the initial radius of the bending of the wire, the gap of the wire in the mouthpiece and the extension. With this method, both longitudinal wire feed and rotation around the axis . This method is used for welding deep holes, [USSR Patent 1834764 dated May 5, 1991]. These methods are useful in MDPPE. Artificial rotation of the PE arc with a fan of drops provides favorable penetration without waiting for natural rotation at high arc current.

The MDPSPE process can be carried out pointwise with breaks for the crystallization of a thin layer of deposited metal, since shrinkage cracks may form in it during surfacing of a thick layer. When surfacing extended products, the MDPSPE process is carried out continuously at a given speed. In this case, the thickness of the deposited layer is controlled by rangefinders (before and after the deposited layer). The width of the deposited bead is determined by the radius of rotation R and the angular velocity of rotation ω of the consumable electrode, while the centripetal acceleration а _n , on which the drop displacement force from the electrode axis depends, is equal to а _н =ω ² R. From this formula it can be seen that even with a small R , but at large ω the deviation of the drops will increase significantly and the width of the bead will increase.

When MDPSPE, in order to prevent deep melting, it is important to control the highest temperature of the product with a pyrometer, which for a moving heat source is displaced from the center of the source, [Barashkov A.S. Calculation of the parameters of a moving surface normally distributed source based on the displacement of the temperature field of a heated flat body from the center of the source // Welding and control - 2004. Collection of reports of the conference dedicated to the 150th anniversary of N.G. Slavyanov. Volume 2. Theory of welding. Perm 2004, p. 267-272].

When MDPSPE of various metals and alloys, argon is used as a plasma gas, and as a shielding gas: - carbon dioxide for steels; - nitrogen for copper; - argon or helium for aluminum and magnesium alloys.

The process of MDPSPE is carried out as follows. All power sources and water cooling of the MD burner are switched on. Shielding gas is supplied to the SPE torch and plasma-forming gas is supplied to the plasma torches. When welding extended products, the movement of the MD burner is switched on. With the help of oscillators in the power sources of plasma torches, auxiliary arcs between the tungsten electrodes and plasma nozzles light up. When the pilot arcs are blown out of the nozzles, the main plasma arcs are ignited, and the pilot arcs are switched off. After heating the product to a predetermined temperature, the wire feed and rotation are switched on, and the PE arc is excited. It should be noted that with an increase in the PE arc current and an increase in the wire extension in the plasma L _P =N _P -L _D , the consumable electrode begins to rotate naturally, so in this case, artificial rotation of the wire can be omitted. Turning off the MDPSPE is carried out in the reverse order.

The burner for 2DPSPE in Fig. 4-5 uses in its design a housing 15, to which the SPE torch 5 and two plasma torches 2 are attached. Two inclined plasma arcs from the plasma torches are evenly spaced relative to the common axis of the MD burner. Inclined plasma arcs are connected at a point above the product on the axis of the MD burner into an axial plasma arc burning on the product. From above, using the mechanism of rotation and wire feed 22 along a common axis, a consumable electrode - wire is fed into the axial plasma arc through the SPE torch with a current-carrying mouthpiece. An arc burns between the PE and the product, inside which there is a jet of drops from the PE onto the product. With the help of the burner attachment bracket and the current supply to the plasma nozzles 23, plasma arcs are excited. Plasma arcs burn from plasma power sources. The PE arc burns from a power source connected to the SPE torch using a current lead 24. Shielding gas is supplied through the protective nozzle of the SPE torch. Plasma-forming gas is supplied to the plasma torches. The SPE torch and plasma torches have separate cooling systems.

The basis of the design of the 2DPSPE burner is the housing 15, Fig. 6-8. The body consists of a protective nozzle 12 of the PPE torch on the axis of the body and two inclined rectangular bases of plasma torches 25. The protective nozzle has an axial hole 16 for installing the PPE torch with a current-carrying mouthpiece, and the bases of the plasma torches have holes 17 for installing plasma forming nozzles and plasma torches are attached to the bases. The axes of the openings of the bases of the plasma torches are connected at a point on the body axis. To ensure that the protective nozzle is paired with the rectangular bases of the plasma torches, the lower part of the protective nozzle opening is made square. To create a three-dimensional structure for the supply of protective gas, the body has two side walls 26. Tubes of a range finder, a pyrometer, a powder supply and a bracket for attaching the burner and supplying current to the plasma nozzles are welded to the side walls. The bases and plasma nozzles are cooled with water through soldered tubes with nipples 27.

The body of the small plasma torch is assembled on a rectangular base 25, Fig. 9-12. The plasma torch has no adjustment of the tungsten electrode relative to the plasma nozzle. The accuracy of the installation is ensured by the accuracy of the machining of parts. The plasma torch is assembled using 4 screws 28, which tighten the parts: a heat-resistant insulator 29 and an electric holder 30 between the cover 31 and the base. The tungsten electrode 21 assembled with the swirler 32 is fixed in a water-cooled electric holder with a nut 33. A current lead 34 to the tungsten electrode is soldered to the tubes of the electric holder. When installing this plasma torch for MDPSPE (Fig. 1), it is fastened with screws instead of a base to the body of the MD burner.

The tungsten electrode 21 must be pressed into the copper swirler 32 with thermal tension, Fig. 13. Since the coefficient of linear expansion of copper is 4 times greater than that of tungsten, press-fitting with soldering and thermal pressing is possible. In FIG. 5 shows a tungsten electrode for welding in reverse polarity. Six-start swirler grooves are made in a conical spiral. The swirling of the plasma-forming gas stabilizes the plasma arc strictly along the axis of the nozzle.

The advantages of the MDPSPE method compared to the SSPE are:

- stable combustion of a multi-arc plasma system without breakdowns on the PE and extinction;

- rotation of the axial plasma arc in the case of MDPSPE will ensure the uniform distribution of the axial plasma arc around the circumference, while heating the PE will increase and the transition to the PE rotation mode will accelerate;

- a powerful, concentrated, axial plasma arc provides a high heating rate of the product, deep resistance during welding, and when surfacing with PE rotation, uniform and shallow penetration is provided with minimal heating of the base metal, which allows the process to be used repeatedly;

- the MDPSPE process is feasible in a wide range of automatic mode and applications.

Claims (3)

1. The method of plasma welding with a consumable electrode, including the supply of the electrode wire along the axis of the plasma welding system from top to bottom to the product, excitation of the arc between the electrode wire and the product, surrounded by an axial plasma arc burning on the product and formed by connecting at least two inclined plasma arcs, uniformly located relative to the axis of the system, characterized in that the inclined plasma arcs are directed to the axial point on the axis of the system above the product with the possibility of forming an axial plasma arc or directed with an offset from the axial point and the axis of the system with the possibility of forming and rotating around the axis of the system of an axial plasma arc, with In this case, all plasma arcs and the consumable electrode arc have the same polarity, and the height of the axial plasma arc is not less than the length of the consumable electrode arc, but less than the value at which the axial plasma arc breaks down on the electrode wire. 2. The method according to claim 1, characterized in that the consumable electrode is simultaneously rotated relative to the axis of the system. 3. A consumable electrode plasma welding system, comprising a body having an axial hole and at least two lateral inclined holes evenly spaced relative to the axis of the body, while in the axial hole of the body there is a torch for welding in a shielding gas with a consumable electrode, in the side inclined holes are installed plasma nozzles of plasma torches, and plasma torches are fixed to the body coaxially with side inclined holes, characterized in that the axes of the plasma nozzles of plasma torches are directed to the axial point on the axis of the system at a distance B from the lower surface of the body with the possibility of forming an axial plasma arc or directed with an offset from the axial point and axis of the system with the possibility of formation and rotation around the axis of the system of an axial plasma arc, while the arcs formed by the plasma torches and the consumable electrode burner have the same polarity, and the distance B is equal to B=Δ-Hp, where Δ is the air gap between the body and the workpiece being welded, Np - in height of the axial plasma arc.

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