Welding is a complex, time-consuming process. Therefore, even when choosing a household welding machine for the home, many parameters must be taken into account:
- Type of power supply: it is preferable to choose models that operate from a standard 220 V network.
- What materials are you planning to work with: for cast iron and copper - you need a device with a current rectifier, for ferrous metal - a simple model is suitable.
- The thickness of the metal being welded is directly related to the strength and power of the current.
WESTER IWT200 - an extensive set of additional functions
The average cost is 9500 rubles.
Specifications:
- Max. welding current - 200 A
- Power - 4800 W
- Full power - 5160 VA
- Voltage - 220 V
- Min. input voltage - 170 V
- Output current - 10-200 A
- Open circuit voltage - 75 V
- Current consumption - 20.3 A
- Min. electrode diameter — 1.6 mm
- Max. electrode diameter — 5 mm
- Type of welding machine - inverter
- Type of welding - arc (electrode, MMA)
The 5.87 kg inverter is practical and easy to use. The case is equipped with a handle, it is possible to connect a transport belt. For welding, consumable electrodes with a diameter of 1.6 to 5 mm are used. The model is equipped with such additional functions as "hot start", anti-sticking, arc forcing. The device copes with voltage drops and its drop to 170 V.
Advantages:
- Protection against overheating and overload.
- Compactness.
- Built-in forced cooling fans.
- IGBT technology, which contributes to an increase in efficiency.
- Low power consumption - 30-40% less than traditional welding machines.
- A long cable-holder of electrodes and a reliable mass clamp allow you to work with any extended object.
- A separate board has been allocated for the controls, which simplifies and reduces the cost of repairs in the event of a breakdown.
Flaws:
- Suitable only for beginners, not intended for complex household work.
Aurora MINIONE 1800 - a rich set of accessories
The average price is 8000 rubles. 
Specifications
- Mains voltage: 220 V
- Current in MMA mode: 20 - 180 A
- MMA current at 100% duty cycle: 31 A
- Rated voltage: 63V
- Protection class: IP 21
- Power factor (COS?): 0.73
- Dimensions: 320x123x220
- Weight: 5 kg.
The inverter is based on advanced IGBT technology and SMT components. The kit includes a two-meter cable, a ground clamp, a holder for electrodes, a case for storage and transportation. The device is successfully used in various fields, including construction, agriculture, during the installation of metal structures. But the operating voltage must be at least 160 V.
Advantages:
- "Intelligent" cooling: the fan turns on only if the board components and power elements are heated.
- Arc force: at the moment when the drop of metal is separated from the electrode, the welding current increases.
- Hot start.
- Antistick - automatic reduction of welding current in case of electrode sticking. The welder gets time to separate the electrode and continue working.
Flaws:
- Poor quality plastic case.
Which welding machine can be recommended for home and garden from these 2 options? Choose by price: where is cheaper.
Svarog PRO ARC 160 (Z211S)
The cost is 9000 rubles. 
Specifications:
- Mains voltage: 220 V (±15%)
- Current in MMA mode: 10 - 160 A
- MMA current at 60% duty cycle: 160 A
- Electrode diameter (min - max): 1.5-3.2 mm
- Protection class: IP 21
- Insulation class: F
- Power factor (COS?): 0.70
- Article: Z211S
- Dimensions: 313×130×250
- Weight: 4.70 kg.
This device is an innovative version of the 2014 inverter. It is capable of operating at low voltage - from 175 V. The main scope of application is surfacing and manual arc welding with an electrode with a diameter of less than 3.2 mm. Manual argon-arc is also possible. But for this you will have to get a valve burner.
Among the features of the model are a knob for smooth adjustment of the welding current, an arc force regulator, a digital indicator that displays the current welding current.
Advantages:
- Five-year warranty service of the device (when undergoing maintenance, starting from the third year of use).
- Light weight - 4.7 kg.
- Metal spatter during welding is minimal.
- Compactness.
- Highly stable arc burning.
- Developed dealer network - about 125 services in Russia.
- Useful features: arc force, anti-stick and quick start.
Flaws:
- Some users complain about the operation of the machine in cases where the seam length exceeds 5 cm.
Resanta SAI 190PROF - suitable for operation in a low voltage network
The average cost is 14,000 rubles. 
Specifications Resant
- Mains voltage: 220V
- Current in MMA mode: 10 - 190 A
- Electrode diameter (min - max): 5 mm
- Rated voltage: 65V
- Protection class: IP 21
- Reference: 65/30
This powerful inverter-type welding machine for home and garden is famous for its ease of operation, reliability and functionality. It is used for manual arc welding. And this brand is perhaps one of the most famous in Russia. Stable burning of an arc provides a dense equal seam. Special PFC technology allows you to work with a voltage drop up to 100 V. Also, the device can be connected to a 4.6 kW generator.
Advantages:
- Convenient arc force adjustment.
- Useful additional functions are “anti-sticking” and “hot start”.
- Compact, comfortable carrying handle.
- Good penetration and minimal metal spatter.
- Digital display showing the welding current.
- Lightness: the device weighs only 8.9 kg.
- Suitability for welding any ferrous metal, stainless steel, copper with a thickness of more than 0.3 mm.
- Energy savings compared to similar devices - 30% (due to the reduced electromagnetic field).
Each installation process requires the right approach. Simply put, the technology must be observed without fail, otherwise final product, if it turns out to be acceptable in appearance, and its structural qualities will not be up to par. Welding works, the technologies of which are diverse, must comply with all prescribed actions, since metal products are characterized by increased strength and safety in operation.
For proper welding of metal, it is necessary to approach this responsibly and competently.
Before applying the features of welding according to the selected technology, you need to understand the properties of steel, the features of the accompanying electrodes and the purpose of the product. Machining, metal technology and welding go hand in hand and cannot be independent of each other.
Materials used in welding
Not all metal welds the same way. The composition began to vary and affect the quality and technology of laying the seam. The general requirements for welding any material must meet such qualities as:
- resistance of the seam to the formation of cracks;
- holding steel near-weld zone;
- determination of the resistance of the metal during the transition to the state of brittleness;
- checking for wear resistance, corrosion and mechanical properties of the welded material.
Requirements for the resistance of the seam to the formation of cracks.
With the help of such requirements, a steel sample is selected. A special welding technology is applied to it, which will be different for other metals. We must not forget that the devices with which the work will be carried out are also technologically different.
In order for the product to function well at any temperature, alloyed and cold-resistant steels are used in welding. Previously, the technology of welding such metals was used only with nickel-containing compositions. Now, with the development of progress in welding, work with a lower nickel content and a low amount of carbon is recommended. This gives advantages in the form of the absence of cracks during hardening, the use of the product in aggressive environments and good weldability with virtually no defects.
Heat resistant steels used in welding in combination with alloyed ones. First of all, it will save both types of metal, especially if you use chrome components. Steels of this quality are strong and have properties that work both for cooling and for overheating.
Aluminum welding is actively used in different types industry, but only as an independent light coating. The interaction with steel is poor, and the technology is not yet available. Therefore, the strength of such a metal depends only on its properties, and pure aluminum is a light and brittle material.
Classification of types of steel for welding.
Carbon steels are the most commonly used welding materials on an industrial and manufacturing scale. Features are susceptibility to melting. Low- and medium-carbon steels are easily amenable to any technology, steels with a high carbon content are considered refractory, but solutions have been created for them.
Influence of impurities on welding technology. Some of them can degrade the quality and properties of the base metal, while others, on the contrary, improve. Impurities include oxygen, bismuth, phosphorus, sulfur and others. Of these, phosphorus, arsenic can be distinguished as good properties that give the quality of the seam (the seams are dense), and a large amount of oxygen, bismuth and sulfur are considered harmful elements (the seams are porous and brittle).
The influence of metals on welding technology is enormous. Long-term and safe operation of the product depends on complex quality indicators. Evaluation criteria were invented under Peter the Great, and are still used in a modernized form. Before a steel is allowed to be welded, it undergoes many bending, torsion, hardness, and tensile tests. The extrusion and upsetting properties are also tested. In order to understand how steel will react to a particular welding technology and subsequent processing, it is necessary to know its structure in order to apply the most suitable one to it.
Welding of high alloy steels
Scheme of features of welding of high-alloy steels.
The technology includes several processes: determining the properties of the metal to cracking, corrosion, changing the structure of steel during welding and cooling the finished seam. The process of welding such metal should go quickly. Arc is more efficient than gas. Electrodes should be selected with austensitic steel content, due to which the seam will be more technological.
After welding, the product or seam must be cooled. But the technology is not finished yet: the seam requires some processing. In addition to beating off the slag, the oxide layer must be removed if the desired product is to have the same qualities as the base metal. This can be done using heat treatment and etching of seams. The second option is more efficient. The product or seam area is immersed in a solution with certain components, and as a result, the oxide should dissolve. The seams are ground, polished and get a surface that meets the standards.
Laser welding of metal
Scheme of laser soldering and welding.
Welding technology consists in high-precision work that does not require subsequent processing. However, due to the cost of the laser, this technology is still applicable only in critical structures. Requirements to appearance are high enough. This technology provides for greater accuracy of the joints of the welded structure and the appropriate processing of the edges. First, metal elements are thoroughly cleaned of scale, rust, cracks are cut, and the oxide layer is removed. Lathes can be used for perfect edges. Degreasing solutions are used, in a word, the metal for this technology is carefully prepared.
Welding connection is butt only. Lap to carbon steels are not used because of the special concentration of electrical stress in laser technology. Helium and argon are used as shielding gases. Laser technology is applied to both light and especially strong metals.
Hot welding scheme.
And if hot welding technology is performed? With such a selected option, the workpiece of the product is subjected to preheating. Then welding is applied, followed by slow cooling. This is the usual way of processing products that have already been in use. Defects must be cut away and a sand mold formed around the weld to prevent molten metal from escaping.
Heating takes place in furnaces or indirect arc, if the product cannot be transported. The advantages are on the side of carbon arc welding. Cooling should be slow, at least 3 days. To do this, the seam is covered with a layer of charcoal and lined with asbestos sheets on all sides. The current can be anything - constant or variable.
Cast iron welding technology
Welding methods for any type of cast iron (grey, white, or half-iron) are difficult, as it is the most capricious metal of all. Its features lie in the strong fluidity of the metal under the action of the arc. It forms cracks in technological seams due to the high cooling rate. Mostly, cast iron welding technology is used for repair work or correction of unsuitable castings.
As seams, the choice of electrodes plays a major role.
The main methods of welding cast iron.
Least of all destroy the carbon layer of the metal copper-nickel. However, there are also conditions here: the seam should be shallow, and the depth should be small. There is still a pitfall in choosing such electrodes: copper and nickel alloys have high shrinkage, which can lead to the formation of hot cracks.
The technology of welding cast iron with the help of steel studs, which are pre-screwed into heavy and bulky products, is widespread. They are scalded together with cast iron at low currents in order to reduce the appearance of white cast iron: it is even more brittle when cooled.
aluminum welding technology
Its choice is limited due to the properties of the metal itself. Having a low melting point, it has a high fluidity during operation. The strength of such a metal is also low, so preventive measures must be taken at the preparation stage. Capricious features can be prevented with a closed arc, high concentrated temperatures, and the use of ceramic flux. They help to improve the quality of the seam in any type of welding.
Scheme of argon-arc welding of aluminum.
When working with aluminum melting, the composition of the surrounding atmosphere should also be taken into account: if the humidity is increased, then the seams will be porous, and, accordingly, of poor quality. In addition, if you do not observe a certain "dryness" in the work, the metal is threatened with corrosion.
The technology of welding metals with aluminum is harmful to workers in the zone of excess gas concentration and some degree of radiation. Therefore, the work of one person is unacceptable: there must always be an observer from the outside, ready to resort to urgent assistance if the partner becomes ill from the vapors.
If you have to work in conditions of low atmospheric temperatures, then the organizers of welding work should take care of the facilities that cover the production sites technological processes. Shells or greenhouses must create the necessary temperature inside, corresponding to the technology being carried out. Otherwise, the quality of welding will come to naught. With a strong overcooling of the metal, the seams will be littered with numerous cracks, which, of course, does not contribute to correctness. There should also be provision of heating due to the use of hot welding technologies.
Repair technologies: nuances
Classification of metal welding.
The methods of such welding are different: manual arc, automatic, slag, mechanized, oxygen. The vastness of the use of such technologies is in demand, first of all, in mechanical engineering, construction and housing and communal services. The choice of a particular technology depends on the damage and its availability. Pre-metal is prepared and its characteristics are determined. Then the damage is removed: the edge is removed from the cracks, the holes are cut out and cleaned.
The technology of crack welding goes in two stages: first from the front side, then from the back. The patches are overlapped by corner welding. In addition, we must not forget about giving a convex shape to the welded metal. This is necessary in order for shrinkage to occur without damage. The seams are brought to a smooth state by grinding them.
Details of a complex shape must be cooked by hand. There must be visual observation of the process. In this case, the metal will be used more qualitatively: there will be less slag. But it all depends on the skill of the welder. Damage to thick-walled metals is welded using several technologies: multi-layer seams, two arcs, and a “slide”. Such methods are good for vertical positions.
Bronze and Brass Welding Technologies
Scheme of automatic submerged arc welding of bronze.
Bronze is a capricious metal. In combination with aluminum overlays, it cannot be welded. Pure, without impurities, it is possible to brew using a technology applicable to copper - a tungsten electrode, with additives from phosphorous elements. Welding should go on in a short time without allowing strong heating of the main surface. Rapid cooling and solidification must be applied. Carbon electrodes are also suitable, but at a height of metal with a cast bronze rod. A strong flow of metals cannot be allowed, therefore the process is carried out only in the lower position. The seams obtained as a result of welding are fragile and make up only 75% of the entire strength of the product. This suggests that bronze welding technology is applicable in repair or secondary areas.
Brass is copper and zinc that interact when heated. The technology is not the easiest, because due to the evaporation of zinc, a new element is formed - zinc oxide, which, in turn, is highly toxic. Therefore, subject to the technology of welding metals, it is supposed to work with exhaust devices or in a respirator. The very process of welding brass with additives that reduce zinc evaporation goes well, satisfies the requirements and the quality of the seam, the separated slag is removed quickly. Brass is subject to many types of welding, but due to its fluidity, work can only be done in the down position.
Technology of welding of maraging metals
Microstructure of typical maraging steels.
Due to the reliability of the developed steel hardening technologies, these types of metals can be welded by any type of welding and using various electrodes. More recently, laser welding has been successfully applied to such steel, which shows better results in resistance to cracking or corrosion.
Also widely used is spot welding when working with aging metals. She is good at industrial scale, and for piece products, welded explosion or friction technologies are suitable. But it requires certain conditions in technical equipment.
In order for welding with such steels to be successful, strict adherence to the technologies inherent in it is required: all materials and related elements must be perfectly clean, they are degreased and washed. If fitting joints is required, then this must be done with high quality, otherwise hot cracks may occur. Their elimination is rather problematic. The technology provides for the transition in the process of welding metals from one form to another: this contributes to the elimination of defects in the form of cracks.
Technologies involving welding of refractory metals include zirconium, niobium, vanadium, tantalum. As well as chromium, molybdenum, tungsten.
An abrasive stone is used as a cleaning agent for metals before welding.
Before starting the welding process, it is necessary to prepare the surfaces, joints and ends of the products. An abrasive stone can be used as a cleaning agent, but only if the part configuration is simple and does not have bends, bulges or concavities. Otherwise, special electric scissors are used. But since this can cause the surface to crack, it is recommended that the ends and edges be processed on milling machines. Etching and vacuum annealing are used as surface cleaning.
In the matter of choosing electrodes, a wire of the same composition as the base metal is applicable. Welding modes may vary, which results in different formation of the seam, its structure and mechanical strength of the product itself. For example, an increase in current will lead to an increase in the ductility of metals, but it will have a bad effect on the formation of the seam.
Advanced technologies, such as plasma welding, vacuum or laser welding, will help to cope with all types of steel, but will require great professionalism in work. They are used on an industrial scale: rocket science, the use of precise measuring instruments.
Dissimilar metal welding technology
Table for welding dissimilar metals.
The industry is succeeding in creating alternative products using metal welding. What does it mean? Heavy and expensive products are being replaced by others developed using the technology of compatibility of different structures. Thus, they become more economical, lighter, and their structural qualities improve.
Some welding technologies are carried out using some intermediate metal, in the event that the properties of one and the other do not come together in any way. Then the "layer" will be an excellent barrier in preventing brittleness and the occurrence of corrosion. Naturally, such a metal must be compatible with both one and the other material.
in beautiful ways in some cases, metal soldering, pressure and melting technology will become. They cannot be suitable for all materials without exception, however, they are called upon by their interaction to grab the surfaces of structures. In this case, the technology will be no worse than direct welding of homogeneous metals.
Lead Welding Technology
Lead welding technology.
Lead has been widely used in nuclear and chemical industry due to its own properties. They finish the inner surfaces of vessels and flasks for chemical reagents, since its low interaction with active substances allows them to be transported without fear of leakage.
Preparation for welding lead is carried out carefully: the edges of the metal are cleaned to a shine, and the width of the clean surface should be at least 3 cm from the edge. As an additional cleaning, pickling with a solution of acetic acid or washing with carbon chloride is used to exclude the slightest possibility of dirt penetrating under the weld. Cleaning occurs either immediately before welding, as the metal will attract plaque to itself very quickly, or twice.
Lead welding can also take place in vertical positions because of the ease of melting, and in horizontal because of the fluidity of the metal. Welding is also carried out using a filler wire, which is laid straight end-to-end.
Diagram of lead welding options.
The types of welding applied to lead are different: gas, arc, pulse and cold. They depend on the thickness of the welded metals. The best seams are obtained by applying fluxes, in two or three seam passes. The first will go without filler wire, due to the fact that the edges of the product melt themselves. The second - with an additive and an increase in the weld pool. The third is needed if the thickness of the lead exceeds 20 mm, which means it is considered laborious.
Lead welding is carried out without heating and interruption. If suddenly an electric arc breaks by accident, then you need to clean the connection point in a new way and only then start welding. In order to make the seam smooth, it is permissible to forge it.
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The list of the above technologies is far from complete and not disclosed in terms of specific numbers and indications of steel grades and electrodes. Production tables with specific values are given in the training literature. The technology of metals and welding are concepts that are inseparable from each other, and therefore, without studying the properties of one, the process of the other is impossible. To become a professional in the field of welding, you also need to gain knowledge in metal science in order to know the reaction of metals popular and rare for welding to a particular technology.
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Rules and technologies for welding metals
- 24-10-2014
- Electric arc welding of metals and electrocontact
- Work of an electric arc
- Molten metal protection and fusion by electrical contact
- Technology of electric arc welding of metals
- Welding electrodes: types and selection
- Arc Welding Characteristics: Definition and Significance
- How arc welding is performed: technology
- Start welding: arc ignition sequence
- Electrode movement and weld pool
- Technology of contact, seam and gas welding of metals
- Equipment: choice of welding machine and protective equipment
Welding is a method of joining parts from a homogeneous material: plastic to plastic, metal to metal. During welding, the contact surfaces are melted or tightly compressed. In the contact zone, two materials are fused into one. The result is a strong tight connection between the two surfaces.
Welding is the joining of parts made from the same material to form a single structure.
Fusion welding of metals is used for high-quality hermetic connection of critical parts: pipeline elements, car (bus, plane) body, metal garage walls and gates, sports horizontal bar supports, fittings inside a concrete wall, and much more. What types of welding use modern welding technologies? How is metal welding performed?
Types of welding of metal surfaces
Welding of metals can be carried out with the melting of contact surfaces or with their compression. In this case, the welding processes are called:
- fusion welding (or melting);
- welding by plastic deformation.
Classification of the main types of welding.
The deformation connection can be performed with or without heating. The deformation of surfaces without heating is called cold welding. Under tight compression, the atoms of different materials are at close range and form interatomic bonds. Surfaces are connected.
In fusion welding, the surfaces to be joined are locally heated and melted. Often a third (filler) material is used that melts and fills the gap between the two metals. In this case, interatomic bonds are formed in the liquid melt between the base material and the additive (molten electrode). After cooling and solidification, a continuous welded joint is formed.
Local heating of parts for welding can be carried out by electric current or burning gas. Accordingly, according to the method of local heating, welding is divided into two types:
- electrical (including electroslag, electrobeam, laser);
- gas.
The names are determined by the heat source used. Electricity can work either directly or indirectly. When used directly, electricity heats the metal and filler electrode due to the passage of current through them or the appearance of an arc. In indirect use, various energies derived from the effects of electricity work: the energy of molten slag through which current passes, the energy of electrons in an electric field, the laser beam that occurs when electricity is supplied.
Classification of types of electric welding.
Welding of metal surfaces can be carried out manually or automatic mode. Some types of welded joints are possible only with the use of automation (for example, electroslag or seam), others are available for manual welding devices.
Electric welding is represented by two methods:
- electric arc;
- electrocontact.
Let us analyze in more detail how the surfaces are connected in the arc and contact welding methods.
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This type welding uses the heat of an electric arc to heat it. The arc formed between metal surfaces is a plasma. The interaction of metal surfaces with plasma causes their heating and melting.
The principle of operation of electric arc welding.
Electric arc welding can be performed using a consumable electrode or its non-consumable type (graphite, carbon, tungsten). The consumable electrode is both the exciter of the electric arc and the supplier of the filler metal. With a non-consumable electrode, a rod is used to initiate the arc, which does not melt. The filler material is introduced into the welding zone separately. When the arc burns, the additive and the edges of the parts melt, the formed liquid bath after solidification forms a seam.
In some technological processes, the joining of surfaces occurs without the supply of filler material, only by mixing the two base metals. This is how welding with a tungsten electrode is performed.
If the electric arc does not burn freely, but is compressed by a plasma torch, while an ionized gas plasma is blown through it, then this type of welding is called plasma welding. The temperature and power of plasma welding are higher, since when the arc is compressed, a higher temperature of its combustion is achieved, which makes it possible to weld refractory metals (niobium, molybdenum, tantalum). The plasma gas is also a protective medium for the joined metals.
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Scheme of electrocontact welding.
If, during arc burning, metal surfaces are protected from oxidation by gas or vacuum, then such a connection is called welding in a protective environment. Protection is necessary for welding reactive metals (zirconium, aluminum), critical parts made of alloyed alloys. It is possible to protect welding with other substances: flux, slag, flux-cored wire. Accordingly, the welding methods used were named: submerged arc welding, electroslag welding, vacuum welding. All these are varieties of the electric arc method that use a different protective environment to prevent the oxidation of the melt, changes in its chemical composition and loss of properties of the welded joint.
Electrocontact welding uses the heat generated at the point of contact between the two surfaces to be welded. This is how spot welding is performed: the parts are pressed against each other with force until they touch at several points. The points of contact will be the places of maximum resistance and the greatest heating of the surface. Due to this heating, the melting and connection of metal elements at the points of contact occurs.
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The principle of connection and operation of electric arc welding.
The technology of welding metal using an electric arc consists in a sequence of actions to organize the operation of the welding machine and the direct execution of welding.
The preparation consists in installing the welding inverter, selecting the electrodes and performing the necessary beveling (surface preparation).
After the welding machine is installed at the place of welding, the contact wire is attached to one of the contact metal surfaces with the help of a "crocodile" (the design of the connecting terminal). Turn on the welding machine and set its strength with a current regulator. The current strength is regulated by the size of the electrode and the thickness of the parts to be welded. For an electrode with a diameter of 3 mm, the current strength should correspond to 80-100 A.
If the metal surface is painted or oxidized to form a layer of rust, it must be scratched with a wire brush to ensure proper contact in the joint.
The type of connection of contact surfaces is determined:
- butt;
- overlap;
- angular;
- tee;
- end.
Types of welded joints and seams.
Let us consider in more detail the features of welding various types of joints. A butt joint often requires preliminary preparation of the edges of the surfaces to be welded: bevels are made along their edges. V-shaped bevels are made along the edges of sheets with a thickness of 5 to 15 mm, X-shaped bevels - on sheets with a thickness of more than 15 mm. Removing the V-shaped edge at the junction of surfaces allows you to get a recess along which welding is performed. X-shaped edges suggest the presence of a recess and the execution of welds on both sides of the connection.
Corner and tee joints can also be made with beveled edges (with surface groove) or without bevels and grooves (depending on the thickness of the welded section).
T-joints and corner joints allow you to connect parts of various thicknesses. In this case, the position of the electrode should be more vertical to the surface, which has a greater thickness.
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The electrode for welding is a metal rod coated with a coating. The composition of the coating is designed to protect the metal weld from burning out during oxidation. The flux displaces oxygen from the molten metal, which prevents oxidation, and releases a protective gas, which also prevents oxidation. The composition of the coating includes the following components:
Scheme of the electrode for welding: 1 - rod; 2 - section of the transition; 3 - coating; 4 - contact end without coating; L is the length of the electrode; D - coating diameter; d - nominal diameter of the rod; l - length of the end stripped from the coating
- ignition and combustion stabilizers (potassium, sodium, calcium);
- slag-forming protection (spar, silica);
- gas-forming (wood flour and starch);
- refining compounds (for removing and binding sulfur and phosphorus, impurities harmful to metal welding);
- alloying elements (if the seam needs special properties);
- binders (liquid glass).
Industrially produced electrodes have a diameter of 2.5 to 12 mm; for manual welding, 3 mm electrodes have received the greatest use.
The choice of electrode diameter is determined by the thickness of the surfaces to be welded, the required penetration depth. There are tables that give the recommended values for the diameters of the electrodes, depending on the thickness of the surfaces to be melted. It is necessary to know that a slight decrease in the diameter of the electrode is possible, while the process time increases. The smaller diameter electrode allows better control of the process, which is important for a novice welder. A thinner electrode can be moved more slowly, which is important in the learning process.
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Before starting welding, the optimal characteristics of the welding process are determined:
Current selection table for welding.
- Current strength (adjustable on the welding machine). The current strength is determined by the diameter of the electrode and the material of its coating, the location of the seam (vertically or horizontally), and the thickness of the material. The thicker the material, the greater the current required to heat it through to melt. Insufficient current strength does not melt the weld cross section completely, as a result there are lack of penetration. Too much current will cause the electrode to melt too quickly, when the base metal is not yet melted. The recommended current value is indicated on the packaging of the electrodes.
- Current properties (polarity and gender). Most welding devices use direct current, it is converted from current by a rectifier built into the machine. With direct current, the flow of electrons moves in one (specified by polarity) direction. Polarity during welding determines the direction of movement of the electron flow. The existing polarities are expressed in the connection of the electrode and the workpiece:
- straight line - the part to "+", and the electrode to "-";
- the reverse - the part to “-”, the electrode to “+”. Due to the movement of electrons from “minus” to “plus”, more heat is released on the positive “+” pole than on the negative “-”. Therefore, the positive pole is placed on an element that requires more significant heating: cast iron, steel with a thickness of 5 mm or more. Thus, straight polarity provides deep penetration. When connecting thin-walled parts and sheets, reverse polarity is used.
- Arc voltage (or arc length) is the distance maintained between the tip of the electrode and the metal surface. For an electrode with a diameter of 3 mm, the recommended arc length is 3.5 mm.
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Ways to ignite the welding arc.
To initiate an arc, a new electrode is inserted into the clamp and tapped against a hard surface to remove the coating on its working end. Under the slag there is a metal additive, the slag itself serves as insulation and closes the additive from ignition. After that, the electrode rod is brought closer to the metal surface at the minimum possible distance, 3-5 mm, avoiding touch. In this case, the electrode is held at an angle to the surface of the metal to be welded. The technology of welding metals with an electrode regulates the angle of inclination of the electrode in the amount of 60-70ºC. Visually, such an angle is perceived as almost vertical, with a slight slope.
To ignite the arc, an electrode is struck on the surface of the metal, like lighting a match on a box of sulfur.
If the electrode is too close to the metal surface to be welded, sticking and a short circuit will occur. For those who start cooking, the electrode sticks often. As you gain the skill of correctly positioning the electrode over the metal, maintaining the optimal sticking distance should not occur. A stuck electrode can be torn off by tilting it to the other side or turning off the welding machine.
If the electrode sticks too often, the current may not be strong enough and should be increased.
With the optimal correct distance of the electrode from the place of welding (about 3 mm), an arc is formed with a temperature of about 5000-6000ºC. After the arc has ignited, the electrode can be slightly raised from the working surface by a few millimeters.
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Scheme of the weld pool.
When the electrode and the base material melt, a weld pool (pool of molten metal) is formed.
The electrode and arc, together with the weld pool (molten metal zone), move smoothly along the connection line. The speed of movement of the electrode is determined by the rate of melting of the metal and its color change. Rapid movement of the electrode is carried out when working with thin sheets that heat up quickly and easily form a weld pool. The slow movement of the electrode is used on thick massive joints.
The shape of the electrode movement (straight, zigzag, loops) is determined by the width of the weld and the depth of penetration. The electrode can move in a straight line (evenly) with a small welding width. It can move in loops, zigzag, if it is necessary to weld a sufficient width and depth of the connection. Options for electrode movement are shown in Figure 1.
Figure 1. Ways of moving the electrode.
The convexity of the seam after solidification of the weld pool is determined by the position of the electrode during welding. If the electrode is located almost vertically, the seam will be even, and the penetration will be deep. A more inclined location of the electrode forms a convex surface of the welded joint and a decrease in the depth of penetration. Too much tilt of the electrode places the arc in the direction of the seam, making the welding process difficult to control.
For a quality connection, the molten bath must have thin edges, be sufficiently liquid and obediently move behind the electrode.
The bathtub in the light filter (through dark glass) looks like an orange surface with ripples. The appearance of an orange color of the bath (drops of liquid melt) can be regarded as an indicator for further movement of the electrode. That is, if an orange color appears, then we move the electrode further by a few millimeters.
Scheme of the device and the main indicators of the weld pool.
At the end of penetration, it is necessary to increase the size of the weld pool. To do this, the electrode must be held over this point for a few seconds longer.
If through penetration of the material occurs, it is necessary to reduce the current value and take another electrode (smaller diameter). The burnt holes are allowed to cool, slag is knocked off from them and then brewed.
After welding, it is necessary to tap the weld with a hammer. This will remove scale from it and visually check the welded joint for the absence of discontinuities or lack of penetration.
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The technology of metal welding by contacts has some features. The current is connected to the parts to be welded, after which they are brought together until they touch. Contact points appear along the joint surface, in which the metal is heated in a few seconds before it begins to melt. After that, the current is turned off and the butt surfaces are pressed against each other, providing tight contact to the melting points.
Seam welding technology.
During seam welding, the automatic welding machine works. This type of welding allows you to get a smooth continuous seam on long sheet surfaces. In a seam welding machine, the electrodes are rotating rollers. Connected metal sheets are passed between them.
Gas welding uses the oxidation of a combustible gas with a high calorific value, such as acetylene, propane or butane, to generate heat. Gas and oxygen are mixed inside the burner, from which the flame comes out.
Electroslag welding is a type of welding in a protective environment. In this technological operation, slag is a protective material that protects the molten metal from contact with air. This type of welding is carried out automatically.
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To protect your eyes from burns during welding, you must use a mask with a light filter.
To perform welding, a large electric current is required to flow to the electrode. A modern device that provides a constant supply of current to the welding site is called an inverter. Older models of welding machines were bulky and heavy, new inverters are easy to carry, do not cause network drawdown (this condition is expressed in a loss of voltage and flashing lights all over apartment building or along the entire street of the private sector). Many modern inverters have short circuit protection. When the electrode sticks, the inverter device automatically turns off.
Protective equipment: a mask with a light filter (dark glass). The light filter protects the eyes from burns. Without it, you can get corneal burns of varying degrees: from mild, when the feeling of the presence of sand remains in the eyes, to severe, when it is impossible to restore vision.
The quality of filter protection is determined by the number. The thicker the electrode and the greater the welding current, the more powerful light filter is needed to protect eyesight.
Mastering the intricacies of working with a welding machine, maintaining the correct arc distance, electrode inclination forms the skill of a welder. Professionalism is determined by the ability to manage the process, to obtain a high-quality connection of surfaces.
http://moiinstrumenty.ru/youtu.be/KxvvWzqY26A
Modern welding inverters make it possible to master the art of a welder on your own and perform welding work with your own hands.
moiinstrumenty.ru
Where welding is heading: new technologies and development prospects
Back in 1802, the Russian scientist Vasily Vladimirovich Petrov made a discovery. He discovered that when an electric current is passed through two carbon rods, a high-temperature electric arc occurs between their ends. It was Academician Petrov who not only studied and compiled a description of this phenomenon, but also pointed out the possibility of using the heat of such an arc to melt metals.
For some time this discovery remained only a part of fundamental science. However, by the end of the nineteenth century, welding as a method had become an integral element of many technological processes. In Russia, electric arc welding was first used at the Kuvaevskaya manufactory and the Ponomarev plant in Ivanovo-Voznesensk. In 1888, this method was used in the workshops of the Oryol-Vitebsk railway for the repair of locomotive and wagon wheels, frames, gratings, and so on. Within five years, this method has spread throughout Russia.
Since then, welding technology, of course, has stepped far forward and penetrated almost all areas of the industry. According to experts: “More than half of the gross national product of industrialized countries is created with the help of welding and related technologies. Up to 2/3 of the world consumption of rolled steel goes to the production of welded structures and structures. In many cases, welding is the only possible or most effective way creating permanent joints of structural materials and obtaining resource-saving blanks, as close as possible in geometry to the optimal shape of the finished part or structure.
By the way, welding is currently used to connect not only steel structures. “Today, welding is used for the permanent connection of the widest range of metallic, non-metallic and composite structural materials in the conditions of the Earth's atmosphere, the World Ocean and outer space. Despite the continuously increasing use in welded structures and light alloy products, polymer materials and composites, steel remains the main structural material. That is why the world market for welding equipment and services is growing in proportion to the growth of world steel consumption. By the beginning of the XXI century. it is estimated at about $40 billion, of which about 70% is for welding consumables and about 30% for welding equipment” (ibid.).
The fundamental question for the industrial gases industry is: how will the market for welding and welding equipment change? What trends will take over?
Experts believe (although it should be borne in mind that this is only a forecast): in the foreseeable future, contact and arc welding will remain the main methods of joining. At the same time, a noticeable increase in the use of laser technologies is expected. Although they will still remain "in the minority", but their share will increase to 6%, and possibly up to 8%.
But the forecast for gas cutting and welding is rather negative. According to experts, the share of the corresponding equipment will decrease. However, not catastrophically: it will remain significant. So the creation of new equipment for welding and cutting will remain one of the main tasks of the designers of the industry.
If we talk about welding technologies, it is worth mentioning one more direction: the creation of tools and methods that make it possible to control the quality of welding without destroying it, both in the factory and in the field. In particular, we are talking about portable ultrasonic testing equipment.
A significant direction in the future development of welding technologies directly intersects with the science of materials. It is necessary to create complex composite materials, as well as high-strength steels. Alloys containing metals such as lithium, scandium, and zircon are now increasingly being used. Work is underway to create well-welded titanium alloys. Finally, continue active research on the creation of special materials based on polymers. This, according to scientists, should increase the characteristics of rigidity and strength.
If we talk about more "mundane" things, then one of the most significant trends in the welding business is the transition to computer simulation of the relevant processes that is taking place literally before our eyes. Where previously a whole was required hardware complex, today one device equipped with the necessary "peripherals" is enough.
Automation allows the use of fundamentally new methods of electric welding. They are based on a rapid change in current, a combination of its high and low pulses, etc. All this makes it possible to weld complex materials, reduce the time required for work, and improve the quality of work. In addition, the requirements for the qualification of a welder are reduced: a normal ordinary professional with such equipment is able to do what previously required a truly unique specialist.
Considering the scope of our magazine's interests, it makes sense to dwell separately on novelties directly related to gas welding and cutting. Even short review shows: here for recent times there were a lot of interesting things.
So, one of the interesting areas of work is the creation of portable devices: light and compact. Today, manufacturers already offer ready-to-use kits (including a system automatic feeding wire) weighing less than 10 kilograms, they only need to be connected to a gas cylinder.
In addition, such a device is equipped with a digital control system. With the help of the display and setting buttons, not only a professional, but even an “amateur” (ie a person who does the relevant work only from time to time) sets the initial indicators: for example, the type of gas and the diameter of the wire. The device then sets itself up. This makes it extremely easy to manage, and therefore convenient for a wide range of consumers.
Another direction is the improvement of gas burners. It would seem, what could be more primitive? However, burners of modern designs are capable, for example, of long-term operation at high temperatures to give an even flame: without torches and pops. This is extremely important for high quality welding. The use of such burners allows you to not interrupt the work, which means that it significantly increases the productivity of the welder.
By the way, the gas burners used in large-scale industries for processing large-sized parts are also being improved. Such multi-nozzle units are used, for example, to bend and weld large diameter pipes. In this case, linear burners can create a flame width of up to several meters.
Finally, a direction worth mentioning is the emergence of portable metal cutting machines, which involve the use of liquid rather than gaseous fuel. The device has a small tank (for 1.5 liters of fuel), and is also connected to a conventional electrical network.
A heating element is located in the barrel of such an apparatus. Thanks to this, it is no longer a liquid, but a gas that approaches the burner nozzle. It is then ionized and used to cut metal in the form of a plasma torch.
This approach has several important advantages. Firstly, a liquid that turns into a gas itself creates the necessary high pressure. Therefore, there is no need to form it by special means. And secondly, liquid fuel is capable of creating much more heat. So, such a device has a much higher autonomy.
Thus, even a cursory review shows that the welding market continues to develop. And there is enough space on it for a variety of technologies. But still, you have to fight for it.
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Modern welding technologies - fantasy or real benefit!?
The main factor ensuring the competitiveness of products in terms of their cost and quality is the level of production technologies. And technological development is always associated with the acquisition of modern equipment and automation of production processes.
Modern technologies automation of welding production allow the use of automatic welding processes in single and small-scale production. There are a great many methods and equipment for automating the welding of pipeline parts. The body elements in their bulk are welded in a shielding gas environment with a consumable electrode. Automatic installations can be equipped with modern welding robots, which allows you to weld products complex shape and a large number of welded joints in the structure. Particular attention should be paid to modern technologies for automating welding of large-sized, thick-walled body products of ball valves, sliding gate valves, as well as pipeline elements. One of the more commonly used is submerged arc welding technology.
Solving Quality Connection Issues
The first land pipeline using mechanized semi-automatic CO2 welding was laid in the USA in 1961. By this time, five mechanized systems for gas-shielded consumable electrode welding had been developed.
In the 1970s and 1980s, MIG/MAG (consumable electrode gas shielded) welding systems were further developed, becoming more common and reliable. The speed of laying the pipeline depends on the speed of welding the root pass of the joint. Therefore, the installation of welding heads on centering devices located inside the pipe was the next step forward. From the very beginning, the possibility of mounting two welding torches on one welding head was demonstrated in the Soviet Union as early as 1961. This system has been successfully used, for example, by Serimer-Dasa since the nineties. It was later discovered that both wires could be located closer friend to each other, using a single gas shield and remaining electrically isolated from each other. Further developments made it possible to replace the two burners of the system with double (tandem) burners. This process is called "Dual-Tandem process". This made it possible to further increase the productivity of welding. However, high total heat input can affect the mechanical properties of the weld, especially for pipes made of high strength steel (for example, X80 and above). Manufacturers are currently working on the optimal alloying of the welding wires used to weld pipes made of these steels. Creation industrial way automatic submerged arc welding and its introduction into production in our country is inextricably linked with the name of Academician E. O. Paton. As a result of many years of hard work of the staff of the Institute of Electric Welding. E. O. Paton created a technology for submerged arc welding, developed compositions and methods for the manufacture of fluxes, and created original designs of automatic machines.
In the middle of the 20th century, it became known that the use of flux helps to solve a number of problems in obtaining a high-quality welded joint. It was supposed not only to isolate the liquid metal of the bath from air, but also to ensure the introduction of additional alloying elements in a strictly defined amount into the metal weld, to bind and convert harmful impurities (sulfur and phosphorus) into slag. The flux, and after melting the slag, must quickly and actively interact with the liquid metal of the bath and drops of the electrode metal and also quickly leave the metal bath as soon as the necessary metallurgical reactions are completed. Slag after cooling should be easily separated from the seam. At present, many specialized enterprises manufacture pipeline parts by centrifugal electroslag casting. This casting method and technical processes based on it, developed at the Institute of Electric Welding. E.O. Paton, provide high quality cast metal due to its refining in the process of electroslag melting and the use of special technological methods to obtain directional crystallization during casting. All properties, at the same time, are not inferior to forged ones and surpass them in terms of plasticity and impact strength, with the same strength. Submerged arc welding is widely used in the manufacture of welded-cast, welded-forged and welded-stamped structures, as well as in connecting pipeline parts. Products created using this welding method operate in the entire range of natural climatic temperatures, at ultra-high temperatures and in deep cold conditions, in aggressive environments and at pressures significantly different from atmospheric.
Increase productivity through automation
Rice. 2. Automatic consumable electrode welding
Submerged arc welding (Fig. 3) (GOST 9087-81 provides various brands of welding fluxes and requirements for them) is the most common method of mechanized arc welding with a consumable electrode. In submerged arc welding, an electrode wire 1 of great length is used, rolled into a cassette or into a coil. Its supply to the arc zone as it melts, as well as its movement along the edges to be welded, are mechanized and carried out by an automatic welding machine with special devices - a hopper 2 for introducing flux into the welding zone and suction 11 of its unmelted part 10 from the seam to return to the hopper. Before starting the process, the flux is poured along the edges of the fasteners to be welded in the form of a roller 50–60 mm thick. The arc 3 that occurs when the machine is turned on burns between the end of the electrode and the workpiece. Under the action of the heat of the arc, the electrode wire 1, the base metal 4 and part of the flux 5 are melted. The arc burns in a closed cavity 6 (gas bubble), bounded in the upper part by a slag shell, and in the lower part by a weld pool 7. The cavity is filled with vapors of metals, flux and gases. The resulting static pressure maintains the flux dome, which prevents splashing of liquid metal and disruption of the weld formation. The molten slag has a lower density than that of the liquid metal, therefore it floats to the surface of the liquid metal of the weld pool and covers it with a dense layer. As the electrode moves forward, the metal and slag baths solidify with the formation of a weld 9 covered with a solid slag crust 8. After welding, the slag crust is removed from the pipe surface. Good contact between the slag and the metal surface, the presence of a space isolated from the external environment provide favorable conditions for protection, metallurgical and heat treatment of the bath and thus contribute to the production of welds with high mechanical properties. Very promising is the use of tape instead of electrode wire. Electrode strips are usually up to 2 mm thick and up to 40 mm wide. The burning arc moves across the strip, melting it evenly. By changing the shape of the tape, you can significantly influence the shape of the seam, changing its width and penetration depth, depending on the quality and type of the connecting pipeline. Submerged arc welding is carried out on direct and alternating currents. AT this case the role of a welder working with a welding machine is reduced to setting the operating parameters of the mode, monitoring the process and adjusting it using the control panel. The arc under the flux is invisible, thus excluding the possibility of visual observation of the process. At the same time, this ensures the practical absence of such adverse factors for the welder as radiation, welding fumes and spatter. | Influence of welding mode parameters on the shape of the seam | ||||
| Increasing Mode Parameters | ||||
| Welding current up to 1500 A | ||||
| 22–24 to 32–34 34–36 to 50 | ||||
| The angle of the electrode to the vertical: | ||||
| Displacement of the electrode against the rotation of the pipe: when welding from the outside when welding from the inside | ||||
| Displacement of the electrode along the rotation of the pipe: for external welding for welding from the inside | ||||
| at a constant current strength at a constant supply | ||||
| 1. The influence of each of the parameters of the welding mode was evaluated under the condition that the remaining parameters remain unchanged. 2. Symbols: 0 - does not change; + - slightly increases; - - slightly decreases; + + - increases; - - - decreases; Intensively increases; - - - - intensively decreases. |
The method of automatic submerged arc welding is used in the manufacture of units, sections and other assembly units of pipelines from all steel grades in the factory. It is also used in the enlargement of assembly units into assembly blocks at the construction site. By submerged arc welding, rotary vertical joints of pipes and pipeline parts with a diameter of 219 mm or more are welded with a wall thickness of at least 7 mm. In automatic submerged arc welding of steel pipelines, General requirements to the assembly and welding of structures. Taking into account the specific conditions of the submerged arc welding process, as well as the design features of pipelines, it is recommended to weld pipes and pipe parts along a previously applied welding seam (root layer), i.e. use a combined method of welding. The specific conditions for welding the annular joints of pipe sections determine the significant differences in the technology and technique for performing automatic submerged arc welding in field conditions from factory welding. The most characteristic feature of welding on pipe welding bases is the need for submerged arc welding of rotary pipe joints along the groove intended for manual arc welding. With such cutting edges, the root layer of the seam must be performed by manual arc welding. Subsequent layers of the seam are welded under flux. According to the second option, the cutting of edges with the help of special machines is processed in order to increase the bluntness, which makes it possible to apply two-sided automatic submerged arc welding. The shape and dimensions of the weld significantly depend on the main parameters of the welding mode. Qualitative assessment the influence of the mode parameters on the dimensions and shape of the weld when welding pipes is shown in Table 1. I would like to summarize, outlining all the obvious advantages and disadvantages of the automated type of welding of flanges and pipeline parts. The advantages of automatic welding over manual welding are: - Facilitate the work of the welder.
- Increase in productivity by 5–10 times, and when welding at high currents (forced modes) by 10–20 times.
- High quality and good formation of seams; seams have greater strength, ductility and impact strength.
- Burnout and spattering of metal is only 1–3% of the mass of the electrode wire. Compare with 5% loss in manual open arc welding.
- Ability to weld metal of significant thickness (up to 20 mm) without cutting edges.
- Low consumption of welding wire and electricity and low total cost of welding.
- Production of metal structures with a large length of straight or circular welds with high accuracy of fitting parts.
- Welding of thick metal structures.
- Manufacture of critical structures designed to operate in conditions of deep cold, high pressures, aggressive liquids and gases.
- Bulk and large-scale production the same type of products.
- Connection of parts with a thickness of 2 to 100 mm with a wire with a diameter of 1.6 to 6 mm, with a welding current of 150 to 2000A and an arc voltage of 25 to 46V.
- It is impossible to weld in horizontal, vertical and overhead positions in space.
- Welding is ineffective with short seams.
- It is practically impossible to weld workpieces of different thicknesses and thin (less than 1.5 mm) workpieces.
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Buying a good welding inverter so that it can be used at work, at home and in the country, where 220V is not always the case, is a difficult task. We will try to help with this.
Thanks to the development of inverter technology welders have become compact, economical and easy to use even for beginners. Thanks to this, you can meet a manual arc welding machine or a semi-automatic device in many garages and private workshops. stable and high demand on welding inverters forces competing manufacturers to constantly improve their the lineup, reduce prices and develop branded services.
Selection criteria
Choosing the best welding inverter is quite difficult - there is such a variety on the market that it takes your breath away. But experienced welders do not try to experiment, referring to the products of already familiar manufacturers. Choose only time-tested and own work brands. After all, if the manufacturer is serious, then he always keeps the quality at a high level - both in semi-professional and in professional devices.
Therefore, before buying a new inverter, they look at the products of those manufacturers that have already been in operation. Even if they did not work themselves, then colleagues will advise. Based on many years of experience, a list of leading manufacturers of welding inverters has been formed, which we bring to your attention, taking devices “for work and at home” for comparison. That is, with which you can both earn money and cope with household chores.
Depending on the mode of operation, inverters are divided into three categories:
- apparatus for manual arc welding (MMA);
- semi-automatic (MIG/MAG);
- devices for argon welding (TIG).
The connection of optical fibers by welding is the highest quality, durable and reliable. Welding machines are complex high-tech devices. They combine precision mechanics for 0.1 µm fiber alignment, high quality optics for fiber position estimation, and software that process manager alignment and welding of fibers, as well as providing control of the apparatus.
This article will consider welding machines from leading manufacturers.
At present, the most famous domestic market won devices from Fujikura, Sumitomo, Fitel (Furukawa), Ericsson and Corning. Separately among the modern welding machines is the OptiSplice LID model manufactured by Corning. A characteristic feature of this device is the ability to measure real losses at the point of the welded joint, which is carried out directly in the welding process. The device is also equipped with a global positioning system (GPS), which, if necessary, makes adjustments to the welding program.
Splicers can be divided into two classes according to the way the fibers are aligned during the splicing process - cladding alignment and core alignment. When using the core alignment method, a higher quality connection is achieved, which is extremely important when working with single-mode fibers, as well as during installation optical lines long-term connections.
Machines that use the cladding fiber alignment method are mainly used for splicing multimode fibers or single-mode fibers where the length of the line is not large.
All modern devices can splice both single-mode and multimode fibers, as well as fibers with a shifted dispersion region. Losses at the welding site, regulated by the manufacturer, do not exceed 0.02 dB. Welding works can be performed both in stationary and field conditions. To do this, almost all devices provide the ability to power from the battery. A number of welders are supplied with cords for connection to car cigarette lighters.
In addition to reducing the weight and size of the machine and reducing welding time, manufacturers are making other changes to the design of welding machines. So, for example, the latest models from Fujikura - FSM-60S and FSM-18S - have increased dust and moisture resistance and a shock-resistant case, which guarantees the device's performance under mechanical stress (for example, when dropped from a height of 70 cm).
Consider the lines of welding machines from leading manufacturers.
Table 1. Core alignment welders
Fujikura FSM-60S | Sumitomo Type-39 | Ericsson FSU 995FA | Corning Optisplice LID | Ilsintech Keyman S1 |
||
Types of fibers to be welded | SMF (SM, ITUT G.652), MMF (MM, ITUT G.651), DSF - dispersion-shifted (DS, ITUT G.653), and FTTx fibers (G.657) | SMF, MMF, DSF, NZDSF, EDF | SMF, MMF, DSF, NZDSF, EDF | SMF (SM, ITUT G.652), MMF (MM, ITUT G.651), DSF - dispersion-shifted (DS, ITUT G.653), and FTTx fibers (G.657) | SMF (ITU-T G.652), MMF (ITU-T G.651), DSF (ITU-T G.653), NZDSF(ITU-T G.655) |
|
Welding time, seconds | ||||||
Shrink time | 35 seconds (for Fujikura cases) | 25 seconds (40mm), 30 seconds (60mm) 2 shrink ovens | 37-seconds (40mm), 51-seconds (60mm) | Furnace separately | Less than 20 sec for 60mm | 26-seconds (60mm) 2 shrink ovens |
Number of welding programs | 60 - factory 40 - custom | 200 - custom | ||||
Dimensions, WxDxH, mm | 136 x 161 x 143 | 150 x 150 x 150 | 130 x 260 x 137 | 370 x 220 x 150 | 275 x 200 x 105 | 160 x 190 x 120 |
Resource of electrodes, welding | ||||||
2.7 kg, with battery | 2.8 kg, with battery and power adapter | 2.2 kg, with battery | 2.0 kg with battery | 2.6 kg, with battery |
||
memory, welding | ||||||
Battery, number of welds | 100 (shrinkable) | External power | 100 (with heat shrink), 200 without heat shrink | |||
Interface | USB 1.1, RCA(NTSC) | |||||
Wind protection | ||||||
Protection against moisture and dust |
Table 2. Sheath alignment welders
Fujikura FSM-11S | Fujikura FSM-17S | Fujikura FSM-18S | Corning OptiSplice One |
||
Types of fibers to be welded | SMF, MMF, DSF, NZDSF | SMF, MMF, DSF, NZDSF | SMF, MMF, DSF, NZDSF | SMF, MMF, DSF, NZDSF | |
Welding time, seconds | |||||
Shrink time | 40 sec (KZDS Fujukura) | 35 sec (KZDS Fujukura) | 30 sec (KZDS Fujukura) | 37 sec (40 mm) 51 sec (60mm) | |
Number of welding programs | 60 - factory 40 user | 60 - factory 40 user | 60 - factory 40 user | ||
Number of shrink programs | 10 - custom 20 - factory |
Modern civilization owes a lot to the welding process. Without welding elements, we would not have received transport, huge buildings, technological structures, mobile phones etc. Despite the fact that this physical process has been used for many centuries, it does not stop its progress. Scientists from many countries continue to explore and improve welding mechanisms, apply new techniques and make revolutionary discoveries in this area.
New technologies allow you to achieve a more perfect result using minimal resources. Developments that appear every year make it possible to weld those materials that previously remained outside the boundaries of this technology.
Main innovative directions
All developments in this area are aimed at improving the main indicators of the process at the lowest cost:
- reduction of corrosion and warping of metals during operation;
- increasing the speed of the welding process;
- facilitating the stripping of joints or ensuring the absence of such a need;
- minimum consumption of materials;
- facilitated and simplified process control;
- the ability to connect the thinnest sheets of metal of various grades.
Portable devices
These types of welding machines allowed us to bring welding to a new - household - level. If before the invention of portable devices, such work was carried out mainly by highly qualified professionals, then portable technology made it possible to use them at home.
Firstly, such devices are very light in weight, and therefore it is convenient to transport them. Secondly, the manufacturers supplied them with a complete set ready for use, not forgetting about the electrode supply system (wires weighing up to 10 kg).
The main improvement can be considered that the digital control system is built into the device. On the display, everyone can indicate the main welding parameters: the diameter of the wire to be inserted, the type of gas, etc. Based on the entered data, the portable device independently adjusts itself and performs welding at a level sufficient for non-production welds.
advanced burners
The gas burner is considered the most primitive link during welding, but even small changes in this element have significantly improved the quality of the work performed. Modern designs of burners are made not only from new materials, but have a different diameter of the outlet, which is able to work with non-standard temperatures and create the necessary pressure.
The gas burners offered by scientists have become gearless and highly dynamic, with the help of them, even during a long process at the highest temperatures, you can get a perfectly even flame, in which torches, flashes and pops will not appear. Because of these innovations, the work of the welder does not require frequent stops, which allows you to complete more work in the same time.
Units with numerous nozzles have been developed, which are used to connect large diameter pipes. The width of the flame when using linear burners can reach several meters. This technology is often used to connect parts underwater or in the air, where there is an urgent need for a drastic reduction in turnaround time.
Hybrid laser technology
This method was developed for the automotive industry, but has found application in other industries. A hybrid laser is used to obtain high-quality welds when joining refractory steels when combined with carbon dioxide. This allows you to get perfect welds with precise control of the laser power in the range of 1.5 - 4.0 kW.
Another feature inherent in hybrid laser technology is highest speed consumable electrode and work performed - from 40 to 450 m / h. With the same performance, the thinnest sheets made of automotive steel can be processed, which has led to financial support and improvement of this development by leading automotive corporations.
Double arc welding
Such a technique was developed for large-sized structures, in the manufacture of which thick sheets of hardening steel of such grades as 30KhGSA are involved. The method is based on the fact that two different types of wires containing alloying (heavy-duty) components are simultaneously used in two-arc exposure. The diameter of such electrodes is 5 mm.
To ensure stable arc burning in two-arc welding, a ceramic flux is required, based on ANK-51A ceramics. It is with ceramic flux that this method shows the highest result and the formation of an ideal welded surface.
Gentle technique
For certain jobs, a new, gentle technology has been developed that is very productive, but has a low cost. During the process, special mixtures of protective gases are used: carbon dioxide combined with argon or a mixture of argon, carbon dioxide and oxygen. Compared to the traditional use of segregated carbon dioxide, the resulting seam is smoother and more flawless.
Another positive point is a significant reduction in the cost of the welding process: a smaller number of wire electrodes is consumed for an equal volume of connections made. The savings are about 20%, which is a significant amount on an industrial scale. In addition, during the welding process, the transition to weldable parts becomes very gradual and smooth. Professional welders who were involved in the initial tests of the gentle technique emphasized that the spatter of electrode metals with a multi-component gas mixture is significantly reduced.
Two-component technique
This new method, which has become widespread in developed countries in a short period of time, owes its appearance to the launch of new high-speed trains on railways. The two-component technology is a modified version of the injection method. It made it possible to achieve results that were previously considered mutually exclusive: to ensure the highest plasticity of a seam joint without compromising the wear resistance of the metal in the place of the weld.
Technically, the two-component technique is difficult to perform, since it requires special preparation: there must be molten steel at the work site, which is carefully placed in liquid form in the gap between the rails. In order to give the compound an impressive viscosity, melting with low-alloyed components is used. Wear resistance is increased through the use of ceramic fluxes, which allow, after filling the weld joint, to remove alloying additives from the process. Ceramics are destroyed under the action of high temperature, and additives that strengthen the connection solidify on the surface, ensuring long-term operation without cracks and deformations.
Orbital Argon Arc Technology
This technology has found application in the aerospace, automotive and semiconductor industries. This technique is highly specific and is used for objects with complex structural contours. It was first developed 50 years ago, but it has been significantly improved by using a tungsten electrode.
The main advantage of orbital argon-tungsten arc welding is that the consumption of activating flux with this method is record low: only 1 g of flux is consumed per 1 m of the weld. This makes it possible to carry out the process at a reduced current, which reduces not only the volume, but also the weight of the weld pool. At the same time, the quality of the connection is regulated in real time by adjusting the arc pressure.
This technique is successfully used when it is necessary to combine heat-resistant, high-strength alloys, carbon steels, titanium, copper and nickel.
SMT technology
This technique is based on the cold transfer of metals. When they talk about cold transfer, they don't mean really low temperature, it's just much lower than with the classic versions.
The main difference is that the blanks and the zone of the future seam do not warm up to the maximum values, so the heat input in the processing area is significantly reduced. Due to the fact that the metal does not overheat pointwise, severe deformation does not occur. The operation of the electrode is based on a controlled short circuit, which is terminated by quickly moving the wire away from the discharge zone and quickly returning it again (up to 70 times per second).
The application of CMT welding is carried out through automated systems that give very uniform and high-quality seams at the junctions of galvanized or steel sheets with aluminum alloys.
In this case, welding is carried out with a short-circuited arc with systematic interruptions. As a result of such a system, the seam is attacked by hot and cold pulses, which makes it possible to reduce the pressure in the area where the arc enters. By the same principle, spatter is reduced when transferring metals.
Thus, with the help of CMT welding, a standard was reached that was previously considered only theoretical. This is made possible by short circuit control and the complete absence of spatter spatter, which drastically reduces the need for post-weld machining.
This method makes it possible to weld metals of various thicknesses, ranging from the thinnest sheets to weld depths of up to 20 cm. Plasma technology allows cutting simultaneously with welding.
The plasma method is based on ionized gas, which completely fills the space between two electrodes. It is through this gas that an electric arc of a certain power passes, providing a very strong effect.
The use of a plasma generator is a complex process that requires high professionalism and professional skills, so it will not work for domestic purposes. Inside the generator there is a multifunctional welding system that can be used in highly specialized areas.
Computer simulation technology
The most modern direction in welding technologies is rightfully assigned to computer modeling. It is equally suitable for joining the smallest parts with complex contours and for large-scale jobs where you need to control huge areas and many welding machines.
If earlier large-scale work was carried out using many devices or a whole welding complex, then computer modeling allows you to have one functional unit with a branched periphery, equipped with many burners and nozzles.
Full automation allows the introduction of fundamentally new ways of welding, which are not available to most welders. In this case, the welders themselves functionally turn into operators who set all the necessary parameters to the computer, on the basis of which the program sets the optimal values and controls the process. This approach significantly improves the result of the work performed.
New technologies have brought welding to a completely new level. new level, which allows you to perform the welding process in record time with minimal labor and maximum results. At the same time, progress does not stand still, so it is quite possible that in the near future there will be systems that will work autonomously, with little or no human participation. The development of such projects is already underway, and if the tests are successful, humanity will soon be able to get new scales and concepts of welding production.