Plasma welding and cutting metals. What is plasma and how it arises

From positive ions. to negative: welding in a fourth aggregate state, advantages and scope of plasma

Plasma. ionizing gas, the minimum temperature of spontaneous ionization. 5,500 ̊C, with plasma welding heating occurs up to 50,000 ̊C. The anode is the electrode, the cathode. the nozzle. The arc occurs between the electrode and the nozzle, it is blown out with gas, after which a plasma stream forms. Technology is more often used for metal cutting, less often for welding.

Plasma welding processes are regulated by GOST 2601-84, which was introduced in 1985, common to all types of GOST 2601-84. in the USSR. Changed in 1992, reprinted in 1996. The state standard defines the process using plasma as “welding with a melting in which heating is carried out by a compressed arc”.

National Standard of the Federation GOST R ISO 5817-2009 sets the quality levels of welded joints. There are also acceptable deviations as welding of steel, nickel, titanium and their alloys.


To GOST 19521-74 “Welding metals. Classification “, adopted in the USSR in 1975 and later extended, plasma-ray welding is assigned to the class of thermal. In the direction of movements of the plasma jet, it is divided into four subspecies:

Plasma welding technology and arc classification by type of action

According to the heating source, welding with a plasma arc and stream is distinguished. In the first case, the arc is lit between the part and the non.melting electrode, it is also called a direct action arc. In the second. between the plasmotrone tip and a non.melting electrode. this is a plasma arc of indirect action.

The burner (plasmotrotron) consists of a nozzle, where a tungsten electrode is placed. Protective gas, cooling, hot and cold liquids are supplied there. The arc is compressed in plasmoron, after which its power increases. At the same time, gas is supplied, which is ionized, heats up and expands in volume repeatedly. In the front of the welding bath, the material melts and moves under the pressure of the plasma along the walls, forming the seam.

The arc plasma stream is used for connecting and cutting both electrical conductive materials and dielectrics. glass and ceramics. A stream looks like a cone facing the molten surface. Thermal efficiency depends on the current, voltage, distance from the nozzle to the part and the speed of moving the burner.

Stream is welded both below in horizontal and frontal in the vertical position of the product. Argon or helium, which are simultaneously protecting against oxygen, are plasma.forming gas.

Classification by current power

Three types are distinguished depending on the current strength:

  • Microplasma welding, up to 25 amperes. Became widespread due to the property to heat small areas of metal. With this value, the product is not burned through and through.
  • On medium current, up to 150 amperes. Allows you to cook with high accuracy. There is a deep, but not wide melting of the material.
  • On a large current, over 150 amperes. Such power forms a wide arc, which pays the part through. In fact, the part is cut, and then welded. Used to connect particularly durable metals: titanium, highly alloyed steels, alloys with large mi aluminum.

What it is?

Plasma welding is a method in which Argon goes into plasma under the influence of an arc. The plasma generator is the current penetrating the electrical wire aron. But before moving on to the nuances of the method, it will be useful to remind individual points from the course of physics.

Plasma is called the state of the gas into which it transforms under the influence of electric shows. It is formed in a special tip called plasmoron. It is easy to compare it with a burner in ordinary gas welding. Plazmoron is called a bilaterally open cone, which becomes narrow below, a tight electrode is placed in the center of this cone, and below. a nozzle. Plasma comes out of this nozzle under serious pressure.

Argon is plasma.forming gas (with the inclusion of hydrogen, of course). It is pumped into the above cone from above. The field also forms an electric current supply to two poles: the outer zone of the burner and the electrode. During heating and ionization, the gas predictably expands, its internal forces powerfully displace it. The nozzle regulates the supply of plasma. In the workplace, an argon is brought in parallel with the plasma stream, which creates a protective cloud. Its value consists in protecting the alloy from oxygen contact, which is contained in the air.

It is Argon who is responsible for clean seams. Plasma-spiritual welding can be called economical, this is its peculiarity. In order for the device to work, you need to change only electrodes and the same plasmotron. In comparison with other types of welding of care work (and manual too) a little. And other welding varieties can be considered more explosive, it is not so risky to work with plasma.

Pros and cons

The main advantage of plasma welding is high.speed metal cutting. No less attractive in it is the option of using equipment with almost all metals and alloys. The thoroughness of the seam is high. The price of work relative to other types of welders is lower. It is also pleased that the deformation of the metal in the plasma method is not only low, but in fact absent.

But the disadvantages should also be noted:

  • High.frequency noise of ultrasound is not the most pleasant combination;
  • air ionization;
  • electromagnetic radiation in the optical range;
  • The nozzle of the plasma burner is short.lived, since the load is highly temperature.

True, there are disadvantages in every welding technology, so you always have to choose. Sometimes in choosing the species a simple analysis of the principle of operation of the device helps.

Assembly of the device

The assembly of a home.made plasma cutting installation is in the layout of all components of hoses and cables:

  • cables for mass, auxiliary electric shoes and electrodes are connected to proper terminals on the welding inverter;
  • The air hose is fixed to the receiver for the compressor;
  • The wiring going to the circuit breaker with the instantaneous mechanism on the handle is attached to the control scheme.
plasma, welding, cutting, metals


To test the assembled unit, you need to perform a test cutter:

  • submit power to the inverter;
  • After 10 minutes, turn off and control to heating;
  • If it does not heat up, it is once again to supplies power;
  • run the compressor;
  • After filling the receiver, open the air crane and send the air flow through the plasma generator;
  • By pressing the switch button with an instant mechanism, excite an auxiliary electric arc;
  • If it is available, make a test cutter.

At the end of the check, turn off the device from the mains and once again check all the components for heating.

Advantages of plasma welding equipment

Gas.flame welding equipment is in demand in areas where the starting raw materials are sheet metal. These are food and chemical industries, mechanical engineering, energy, electrical engineering, and the production of shield equipment. Next, we suggest you familiarize yourself with well.known manufacturers and consider popular plasma welding installations.

welding equipment

It is important not to confuse plasma installations for welding with metal cutting equipment. The former are still known as plasma-spiritual devices, the latter-air-plasma. The latter are not designed for welding metal blanks!

Among well.known manufacturers stand out:

Read more about the products of these companies and products of a number of foreign companies. in the next sections.


Devices under the Gorynych brand for the formation of plasma use water or its mixture with alcohol, while water vapor performs a protective function. When processing products on top of the seam, a thin anti.corrosion film of oxides is formed.

For welding metal using Gorynych, a gas.tank equipment or transformers are not required, so a tangible plus of devices is their mobility. To activate the equipment, a household network with a voltage of 220 V or an independent current generator is required.

The mobile device of plasma welding “Gorynych” is designed for metal with a thickness of 0.5 to 8 mm. The temperature of the arc formed by water and plasma reaches 6,000 degrees. The requirements for the security of the process are very loyal. For example, a well.thought.out ventilation system is not required, since the air is not only not poisoned by harmful gases, but also partly saturated with oxygen.

  • at 8 A (suitable for small household works, rations; costs 29,000);
  • on 10 A (wide range of capabilities, including metal cutting; 30,000);
  • on 12 A (powerful unit for processing sheets with a thickness of more than 1 cm; 33000).

Consumables for the operation of the equipment are inexpensive. For example, the welder will need a nozzle (about 200) and a cathode (200). The nozzle for cutting costs the same.


The principle of operation of the installation is similar to the MPPK “Gorynych”-the plasma is formed using an aqueous solution. Another similarity is compactness (a power supply along with plasmoron weighs a little more than 6 kg); Here. the lack of strict requirements for ventilation of the premises.

The difference from the previously named brand is in power and, therefore, the cost. The first can be found out from the marking. The popular Multiplase 3500 (3.5 kW) model will cost 90 thousand.


The equipment used an inverter circuit that guarantees the stability of the arc autonomously from the voltage drops. There are sensors that control the temperature of the process and prevent the failure of the equipment. User advantages. compactness, lightness of equipment, accessibility of consumables.

Modification “Plazarium SP 3”, the power of which is 2.6 kW, costs about 40 thousand.

Models of foreign manufacturers

Among the popular plasma cutting devices are noted:

  • Fubag (a German concern representing Plasma 25, 30, 40, 65 tons, 100; are of practicality, high performance, but most models are suitable for metal cutting);
  • Blueweld and Telwin (Italy; the line includes devices with contactless launch; there are single.phase and three.phase devices in T.h. for handmade);
  • Aurora (China; inexpensive devices with a long cable; there is a contactless launch; part of the devices, in addition to plasma, carries out semi.automatic and manual welding, which indicates universality).

An example of a machine for microplasma welding. SBI PMI 50 TL (including BASIC model). The water-alcohol solution has been replaced by an argon-gel or arg-hydrogen mixture. The device can be programmed for a certain mode of operation, combined with robot manipulators. BASIC. high.power apparatus, which has the functions of the base model.

When choosing high.quality equipment for plasma welding, pay attention to the models above these companies. They are distinguished by simplicity of management, environmental cleanliness, efficiency of electricity consumption. A wide range of opportunities displays plasma welding devices for leading positions among analogues, and the moderate cost of models makes the choice of the buyer easier.

What device for plasma welding do you consider the best you? Share your opinion in the Комментарии и мнения владельцев.

Description of the devices

The market has a large number of different companies that sell their products. However, most of these products are designed for metal cutting. In this case, they are often designated as devices for plasma welding. But in the future they turn out to be cutters (CUT). On the other hand, most welding machines have the function of cutting metals. For example, Gorynych devices, multiplase 4000 and Plazarium SP3, in addition to welding, can also cut metal. In this case, water is used as a gas.forming liquid.

The characteristics of some plasma welding devices are given in the table.

plasma, welding, cutting, metals
Name Company Current, a RPOT, kW Gas/protective. HC-ignition Weight, kg Price, thousand.
Gorynych, GP-37-10 Aspromt,

ten 2.5 Alcohol water _ 5.4 29
Plazarium SP3 Plazarium,

4-12 2.6 Water gasoline _ 6 68.9
Multiplasz 4000 Multiplase,

10-180 four Alcohol water _ 28 105
SBI PMI 50 TL BASIC SBI, Austria 0.5-50 5 Ar/ar he 47 Treaty
Microplasma 20 Edm, Germany 0.1-20 fifty Gas fifty 598
SBI PMI 500 TL SBI, Austria 5-500 twenty Ar/ar he 115 Treaty

The first three devices are produced as a plasma-forming environment in them use vapors of water-alcohol (Gorynych and multiplase 4000) or water-bensin (Plazarium SP3) solutions. The first two devices can be attributed to the microplasmic type (plasma current of less than 25 A), and the third apparatus can be considered a medium.power apparatus. It should be noted that each of the companies produces a whole line of devices that have different power. For example, in the family of multiplase devices there are more powerful 7500 and 15000 devices, which accordingly consume greater power and have greater weight.

Further, the table contains the characteristics of professional devices of the Austrian and German companies. PMI series devices are designed for microplasma spot and suture welding. The software of the device saves up to 50 operating modes of the unit. Using the controller, a large number of automatic adjustments of the working cycle of welding are carried out, including gas purge before and after welding, adjusting the operating current installation mode. The main welding parameters are displayed on the touch display. Error or warning signals are also displayed there. It is possible to connect to a computer and control the process remotely. In such devices there are devices of the RF-fasten of the arc.

The approximate cost of devices for welding the PMI series on Yandex.Market

The table shows the characteristics of the SBI PMI 50 TL BASIC device and a more powerful SBI PMI 500 TL with a maximum plasma current of 500 A. Such powerful devices are most often used in robotic production plants.

Even more advanced are plasma welding devices like Microplasma by the German company Edm. On sale there are several models with currents up to 20, 50 and 120 A. The table shows data for a Microplasma 20 type. The unit of this type is designed for microplasma welding with direct current. With its help, you can surf and connecting sheets, foil, grids from Fe, Ni, Cu, AG, Ti and their alloys. The Microplasma 20 device can be used in the production and repair in the aviation, aerospace industries, as well as in electrical, chemical and medical industries.

plasma, welding, cutting, metals

In devices of this type, the welding current settings are used using a potentiometer, adjusting the welding parameters (starting and welding currents, the completion of welding, gas purging time), protection of the welding burner using relay, indication of welding parameters on the display on the display.

The burner is connected to the microplasma apparatus with hoses for supplying protective gas and plasma gas, as well as the supply and removal of coolant. For cooling, a special deionized liquid is used. The welding burner control cable is connected to the device using a 5-pin outlet.

Railroad thermite welding

Device and main types of devices

In general, the composition of plasma welding equipment includes:

  • Burner (plasmatron).
  • Power supply (inverter).
  • Plasma.forming gas.
  • Gag.
  • Water cooling system.
  • Cable package.

The burner is a complex device in which the electrode is installed, there are pipelines for supplying gases and coolant, and also passes an electric cable, according to which the supply voltage is supplied to the electrode.

Scheme of plasma welding

The design of the burner depends on the power of the device. In low-power devices, burners with a retractable cathode are used, which using the control button can close on the anode-salt and excite the arc.

For manual plasma welding, burners are used that have the appearance of a gun. Such a device is convenient to hold in your hands. For plasma-water welding, a burner in the form of a pistol with a discharge camera and a steam-forming device is used.

For more powerful devices, burners with a fixed cathode are used. Its main parts:

The approximate cost of burners for plasma welding for Yandex.The burner market for powerful devices do not have handles, since they are attached directly on manipulators or welding machines.

In devices, inverters are most often used as a power source that almost completely displaced transformer sources. Modern pulsed converters on IGBT transistors provide a stable working current, which can be adjusted for various working modes of operation of the device.

The approximate cost of inverters for plasma welding for Yandex.Market

For plasma formation, air, oxygen, argon and nitrogen are used.

Inert gases are used to protect the welding bath. nitrogen, argon, vapors of alcohol or acetone.

Cable package is designed to connect the device with the burner. The cable package is placed:

  • hoses for supplying working and protective gases;
  • hoses for the supply and removal of water cooling;
  • main current supply wires;
  • lamp wires;
  • Control system circuits.

In household apparatus, only current supply circuits are connected to the burner. Therefore, in this case, they just talk about the power cable.

Pros and cons

Like any technology, plasma welding has positive and negative sides.

  • high speed of melting blanks;
  • accurate and high.quality seams;
  • lack of slag;
  • even edges of the parts during cutting;
  • environmental friendliness;
  • safety;
  • ease of use;
  • Control of the depth of the provar.

Despite the fact that the disadvantages of plasma technology exist, they are insignificant. And the cost of equipment pays off quite quickly, especially a qualified master.

Features of technology

Plasma welding is based on Argonoduga welding technology. The difference in these technologies in the features of the arc. Unlike ordinary electric, the arc of plasma is a compressed plasma stream with powerful energy. To understand the essence of the plasma welding process, you need to know what plasma and the conditions of its occurrence are.

Plasma is a state of gas with its partial or complete ionization. This means that it can consist not only of neutral molecules and atoms, but also of electrons and ions with a certain electric charge or to fully consist of charged particles. To transfer gas into a plasma state, you need to ionize most of its molecules and atoms. To achieve this, it is necessary to attach to the electron that is part of the atom, an effort exceeding its energy connection with the nucleus and help to break away from it.

For this, certain conditions must be created, which were developed in the field of obtaining a plasma arc.

The first mention of the development of plasma welding was in 1950. In 1960, some principles for obtaining a plasma flow were presented and the technology and equipment of plasma welding were introduced. In our country, research in this area and the development of technology was engaged in the Institute of Metals to them. BUT. BUT. Baikova, led the project n.N. Rykalin. After studying the physical properties and energy of a compressed electric arc in an argon environment transformed into a plasma stream, its technical capabilities in the welding field were determined and special equipment was developed.

Plasma stream

The plasma transformation is achieved due to the influence of a strong electric field created by an arc of gas through gas, for a forced gas entering the burner through the nozzle.

Thus, to convert an electric arc into an electrified plasma stream, two conditions must be met:

Compression provides a special plasmotron device. As a result, the thickness of the jet decreases, and the pressure increases. At the same time, gas is supplied to the arc, which is heated under its influence and turns into plasma. Due to heating, an expansion and increase in gas volume occurs. As a result, it rushes from the nozzle at high speed. over, if the usual electric discharge has a temperature of about 5000-7000 ° C, then the plasma can reach 30,000 about C.

For plasma formation, mainly argon with the addition of a small amount of helium is used. The electrode should also be protected by a neutral argon. Wolframa products with the addition of thorium or ite are chosen as an electrode.

Plasma welding technology is characterized by a high temperature and a small arc diameter, which provides its significant power.

Plasma cutting. what is it

What is plasma cutting? This is the processing of metal products, where a chip is a chip of plasma.

plasma, welding, cutting, metals

Plasma, is a stream of ionized gas, heated to several thousand degrees. Contains particles with a positive and negative charge. It has quasineral properties. That is, in an infinitely small volume, the total charge is balanced and equal to zero.

However, the presence of free radicals means that plasma is an electricity conductor. The combination of high temperature, electrical conductivity and high flow rate (more sound speed) made it possible to develop and create plasma equipment in the last century in the last century.

Direct cut

Between the cutter (cathode node) and the product (anode) light an electric arc. Cathode (electrode) is placed inside the body having a nozzle. Gas, under pressure, passing by the electrode, is heated to high temperatures and ionizes. The high flow rate is created when the nozzle passes. Electric shows melts the metal. DISCED GAZ provides a withdrawal from the heating zone.

Carzac of indirect action

This method allows us to process conventional metals, but with low electrical conductivity, and dielectrics. Unlike the previous scheme, the source of the electroisk is placed in the Rezak. Therefore, the effect on the processed products is provided only by the plasma flow. Such equipment costs much more than a direct action model.

Both types of cutters have a general scientific and technical name-plasmatron (literally,-plasma generator).

Advantages of plasma processing

For cutting metal, plasma units are produced by industrial and domestic purposes. The former are a complex multifunctional complex with an automated process (CNC machines). The second are small devices operating from the 220V or 380 V network.

The power of the manual unit is enough for the cut of metal up to 15–20 mm thick. Separate models are equipped with a ignition of an arc. The configuration includes plasmotron and air preparation device.

Used in home workshops, professional production and construction conditions:

  • plasma river of sheet metal;
  • processing of cylindrical products, including steel pipes;
  • clipping of complex geometric shapes, including holes;
  • processing of ceramic and stone products and other types of fishing.

This type of equipment significantly exceeds the functionality and ease of use of ordinary gas acid cutting. Not only in dimensions, but also in safety precautions.

The model of domestic plasmabron is shown in the photo.

Advantages and disadvantages

The main positive points of the plasma method:

  • accessibility. plasmoron supplement the existing basic welding equipment;
  • Due to the high temperature in the working area, under the protective atmosphere, homogeneous in the structure of the connection is formed;
  • the depth of the provar is controlled;
  • The speed of the seam formation is high, the volume of labor costs decreases;
  • Universality. the method is applicable for any alloys, you can cook and cut metal, surf the powders.
  • the cost of equipment and work is high;
  • The complexity of the technological process, certain knowledge and skills, special training are necessary;
  • plasmotron requires additional care, cleaning, replacement of the burner and electrode;
  • It is necessary to supply plasma.forming gas into plasmotron;
  • It is necessary to cool plasmotrone so that it does not fail;
  • Large energy sector.

Plasma welding is more often used in industrial volumes, for individual work this method is too expensive.

Microplasma welding

To connect thin parts from 0.3 to 2 mm thick, repairing medical instruments, microplasma welding is suitable. It is carried out on a small current from 0.1 to 2 A, the thickness of the tungsten electrode does not exceed 2 mm, the diameter of the nozzle of the burner is from 0.5 to 1.5 mm.

Nope and taurus compounds should not be done with this method, and the ends are performed in any position, they do not need a filler wire. Under the butt seams make a lining. Work needs low.ampere inverters, rectifiers generating a stable current to support the duty arc. Among the industrial equipment of manual, automatic microplasma welding there are models that have different operating modes:

When connecting thin parts, this method reduces the risk of burning and thermal deformation of the part due to the narrow zone of warming up. Foil is boiled only with plasma, other methods are not used.

Plasma Cutter PARKSIDE PPS 40 B2 (149€). Unboxing and Test

Distinctive features of the microplasmic seam:

  • resistance to vibrations and blows due to the uniformity of the molecular structure;
  • smooth surface that does not require additional processing;
  • high accuracy, thanks to a focused arc, it is possible to minimize deviations, since the welding bath during the formation of the seam is easy to regulate;
  • good clutch of the edges with a shallow time.

Equipment for microplasma mobile, with gas tank, automatic supply of additives increases the comfort of work.

Plasma welding is one of the promising areas of work. It is applicable for colored alloys, aluminum. Convenient during installation of thermal systems in private houses and for working with electronics. Microplasmic equipment is considered the most convenient. To connect large parts of plasmotron, it is really possible to make with your own hands.