High-quality welding of rail joints. How to choose electrodes for welding Welding a rail with steel

The owners of the patent RU 2270739:

The invention relates to arc welding methods and is used primarily for manual arc welding of railroad rails. The method for welding rail joints includes installing rails with a gap between the edges being welded, introducing a consumable electrode into the gap and welding using molds installed at the welding site at a current strength that ensures the formation of a liquid pool in the entire volume of the gap. The edges of the rails or the edge of one of the rails are preliminarily machined, which includes making a transverse cut along the vertical plane from the head to the beginning of the rail sole, making a horizontal cut along the end surface of the rail perpendicular to the previously made cut, and chamfering the end surface of the sole with blunting at base of the rail foot. When a liquid bath is formed in the root of the weld, the edges of the base metal of the rails are additionally melted. This will make it possible to obtain a weld with mechanical properties equivalent to those of the base metal, which will increase the service life of the rails. 2 ill.

The invention relates to arc welding methods, mainly used for manual arc welding of railway rails.

A known method of welding rail joints, in which the welding of rails are manual arc method (SU 78136, B 23 K 9/02, 1942).

In the known method, the rails are installed with a gap between the edges to be welded from 9-14 mm, depending on the selected electrode diameter, so the weld is obtained mainly due to the melting of the electrode material. The welded edges heat up so much that a common pool of molten metal is formed, which is maintained in a liquid state during the entire welding period. Graphite plates, the inner surface of which is made according to the shape of a rail, can serve as molds. The size and shape of the reinforcement of the weld depends on the size and shape of the corresponding recess that is made in the mold.

The ends of the rails are cut with a rail cutter along a plane perpendicular to the axis of the rail. Bevel edges before welding do not produce.

A large gap between the ends of the rails of the order of 9-14 mm does not allow welding the edges of the sole of the rails, therefore, a forming lining is used to form the reverse side of the weld root. The weld is obtained mainly due to the melting of the electrode material, the molten mass of which fills the gap between the ends of the rail sole and the forming lining.

The most significant disadvantage of this method is the presence of a large gap between the ends of the rails. The molten electrode metal is a natural bridge between the rails to be welded, along which the arc moves from the edge of one rail to the edge of the other. The welded joint obtained in this way has a coarse-grained structure due to overheating of the electrode metal and, as a result, lower mechanical properties than those of the base metal. In the fusion zone of the rail edge with the molten mass of the electrode metal, there is a high probability of occurrence of defects such as lack of fusion, slag inclusions, and pores.

The technical objective of the present invention is to improve the mechanical properties of the weld by reducing the gap between the ends of the rails to a size that allows welding the metal of the sole of the rails and obtaining a weld with mechanical properties that are equivalent to those of the base metal.

The method according to the invention consists in the fact that the edges of the rails or the edge of one of the rails are preliminarily machined, while a transverse cut is made along the vertical plane from the head to the beginning of the rail sole, and then a horizontal cut is made along the end surface of the rail perpendicular to the previously made section, and at the end of the sole, a chamfer is chamfered with a bluntness at the base of the rail sole, rails with a gap are installed, an electrode is inserted into the gap and welding is carried out using molds at the welding site at a current strength that ensures the formation of a liquid pool in the entire volume of the gap, and the liquid pool in the root of the seam is obtained by melting the edges of the base metal.

The differences of the proposed method for welding rail joints are that the edges of the rails or the edge of one of the rails are preliminarily machined, while a transverse cut is made along the vertical plane from the head to the beginning of the rail foot, and then a horizontal cut is made along the end surface of the rail perpendicular to a previously made cut, and at the end of the sole, a chamfer is removed with a bluntness at the base of the rail sole, and a liquid bath at the root of the seam is obtained by melting the edges of the base metal.

The essence of the proposed method is illustrated by drawings.

Figure 1 shows a drawing when machining the edge of one of the rails, figure 2 - the edges of the rails.

In Fig.1 marked: 1 - rail (without edge processing), 2 - rail with a prepared edge, 3 - blunting, 4 - gap between the edges, α - angle between the edges.

In Fig.2 marked: 2 - rail with a prepared edge, 3 - dullness, 4 - the gap between the edges, α - the angle between the edges.

The angle α between the edges lies in the range of 30-60°.

Welded railway rails type P65. In mechanical workshops, distances are measured for a piece of rail 3 m or more in accordance with TU 32 TsP-670-88 and the edges of the rail are prepared from both ends for installation in place of the defective rail. In this case, a transverse incision is made along a vertical plane from the head to the beginning of the rail sole. Then, a horizontal cut is made along the end surface of the rail perpendicular to the previously made cut, and at the end of the sole, a chamfer is removed at an angle of 45° with a bluntness of 2 mm at the base of the rail sole. Markings are made on the rail from which the defective section is removed. A defective piece of rail is cut off, equal in size to the prepared one, and a piece of rail with edges prepared for welding is installed in this place. The gap between the rails was 2 mm (see Fig. 1). The ends of the rails before welding are cleaned to a metallic sheen.

Under the sole of the welded rails, a copper lining forming the reverse side of the seam is installed and fixed with a clamp. The root of the seam is welded with an electrode of the UONI - 13/65 brand, with a diameter of 3 mm, a current of 140-160 A, followed by filling the gap between the ends of the rail foot with an electrode of the UONI - 13/65 brand, with a diameter of 5 mm, a current of 250-280 A.

Lateral copper molds are installed on the neck and head of the rails and fixed with a clamp. The neck and head of the rail are welded with electrodes of the UONI - 13/65 brand, 5 mm in diameter, current 250-280 A.

The proposed method allows to obtain a weld with mechanical properties that are equivalent to the properties of the base metal, while the obtained mechanical properties of the weld increase the service life of the rails to the service life of the rails installed on the track without welding.

A method for welding rail joints, which includes installing rails with a gap between the edges to be welded, introducing a consumable electrode into the gap and welding using molds installed at the welding site at a current strength that ensures the formation of a liquid pool in the entire volume of the gap, characterized in that mechanical processing the edges of the rails or the edge of one of the rails, including making a transverse cut along the vertical plane from the head to the beginning of the rail sole, making a horizontal cut along the end surface of the rail perpendicular to the previously made cut and chamfering the end surface of the sole with a bluntness at the base of the rail sole, and forming liquid bath at the root of the seam is carried out by melting the edges of the base metal of the rails.

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The invention relates to devices for the continuous production of hollow tubes from flat metal strips, and in particular to devices that make it possible to obtain welds without defects when the device is stopped and then started.

The installation of railway lines is carried out by two methods: prefabricated and welded. The second is preferable because prefabricated joints reduce the speed of rolling stock. Welding of rails is carried out by several methods. When choosing a method for mounting seamless lines, the weldability of the material and the cost of work are taken into account. The most common: contact and aluminothermic welding, there are other types. Each one should be mentioned separately. Joints are welded using special equipment.

The railway profile is made from high-carbon steels, characterized by poor weldability. During heat treatment, cracks form on the metal, internal stresses arise. When welding rail lashes, this is unacceptable, web defects can cause an accident.

To work you need:

professional equipment;
quality consumables;
control devices that check the integrity of the seam.

To form a strong connection, thick-walled beams must be welded to the full depth. After welding the joint, it is necessary to level the surface so that the seam does not collapse.

Rail types

To select a welding method, the chemical composition of the alloy is taken into account. For each type of profiles, GOST defines steel grades.

Name	Purpose	Steel grades used for manufacturing
Railway standard	Issued for main roads	RP50, RP65, RP75.
Railway industrial	Used for short distances.	RP50, RP65, RP75.
Railway narrow gauge	They are mounted in mines, on access narrow-gauge railways.	P8, P11, P18, P24.
Mine for mine conductors	They are used for jointless wide-gauge sections, switches	R33, R38, R43
frame	Necessary for installation of intersections of lines.	PP65.
Crane	Designed for the movement of overhead and construction cranes.	KR70, KR80, KR100, KR120 and KR140.
witty	Necessary for turnouts, circular support devices.	OP43, OP50, OP65 and OP75.
Trams with gutters	They are used only for tram tracks, they are designed for a small load.	T58 and T62
Counter-rail	Mounted in dead-end sedimentation tanks.	RP50, RP65, RP75.
Antennae	Are issued for crosspieces with a continuous rolling surface.	UR65

Methods for welding rail joints

When choosing a technology, the weldability of steels, their fluidity, and ductility are taken into account. An important factor is labor costs, the cost of equipment. Taking into account all the components, they decide how to weld the rails.

For sealing joints, the following technologies are used:

electric arc;
electrocontact;
aluminothermic;
gas press.

At enterprises, thermite welding of rails is more often used, less often contact welding. Each technology has its advantages.

Arc

Welding of rails using electrodes is used for joints and lashes. In the bathroom, it is possible to obtain a strong connection. The ends are placed at a slight elevation above the sheet with a gap of 14-16 mm in a special bath that holds the melt. An electrode with a diameter of 5 or 6 mm is placed vertically in the joint. When a high-frequency alternating or direct current of direct polarity is supplied with a power of 300–350 amperes, depending on the thickness of the profile, the melt gradually fills the entire joint. The diffusion layer is created over the entire section. For welding rails, electrodes with the main type of coating are used:

domestic UONI 13/45 and UONI 13/55,
Japanese LB 52U.

They are pre-calcined: they are kept at a temperature of 180 - 230 ° C for 2 hours.

Advantages of electric arc welding:

no need to use flux, the coating creates a layer of slag above the bath, it prevents oxidation;
no preliminary cutting of the ends is required;
no additional effort is required to form a tight connection;
availability, transformers, rectifiers and professional inverters are used as a current generator.

After cooling the bath, the joint is cleaned, the scale is removed, and the surface of the rail head is leveled.

Thermite

The method is based on the ability of aluminum to reduce iron oxide with a large release of heat. mastered over a century ago. When thermite is set on fire, a temperature of 1200 to 2000°C is created in the working area, depending on the chemical composition of the alloy. The reduced iron flows into a mold that matches the profile of the rail.

In addition to iron and aluminum oxide, thermite includes alloying additives, small pieces of metal (they slow down the chemical process). The slag formed during the melt floats, it is removed after the metal has cooled.

The most important advantage of the method is the high speed of thermite welding of rails. It is used for hardened and cold rolled beams. It is used in the installation of main railway lines and lashes.

Gas press

Welding of rail joints by this method is carried out on ductile steels. The temperature in the junction zone of the ends rises due to the shear energy. It is released at high pressure. A high-quality connection is formed due to the homogeneity of the diffuse layer. For tight joining of the rails, the end is cut with a rail cutter. The metal is preserved with 4-carbon chloride or dichloroethane; the metal does not oxidize under the composition. The joint is heated to a viscosity temperature, under a 10–15-ton pressure of a hydraulic press, the layers shift, the ends melt, and a diffuse layer is formed.

The main advantages of the gas pressure method:

homogeneity of the chemical composition;
lack of scale, the process takes place inside the profile;
the ability to connect a profile of any configuration and thickness.

Electrocontact

Automated technology is based on the heating of the joint due to a penetrating electric arc that occurs under the influence of high currents of low voltage. Electrocontact welding is carried out by self-propelled complexes MSGR-500, MS-5002, K-190 directly at the place of laying or with a slight displacement of the branch. Replaceable contact heads are used for different types of rail profile. The work is carried out by the method of continuous reflow or pulse heating of the rails.

Quality control of rail joints

Traffic safety depends on the strength of the joints, therefore, regardless of the method of welding, rail joints are checked by any of the non-destructive testing methods. The seams made by manual welding equipment are especially carefully checked. In addition to the structure, the evenness of the rail head, on which the wheel rests during movement, is checked.

When carrying out installation and repair work on sections of the railway track, as well as in similar conditions associated with the laying of rail threads, special welding technologies are used.

Features of rail welding technologies are expressed in increased requirements for the operational reliability of joints, as well as their resistance to mechanical stress.

Welding of rail joints belongs to the category of especially important activities, the organization and conduct of which is impossible without the involvement of equipment and modern welding mechanisms.

The main types of welding technologies used in the installation and repair of rails are:

electrocontact welding;
electric arc method;
thermite processing (aluminothermic welding of rails);
modern gas-pressure welding.

Each of these methods has certain advantages and disadvantages. For a more complete acquaintance with them, we will consider each of the listed welding methods in more detail.

Electrocontact method

The electrocontact approach to connecting rail joints is based on their strong heating and subsequent melting by means of an electric arc, which is formed by a significant low voltage current.

To implement the method, special machine systems are used that operate in automatic mode (MSGR-500, MS-5002 or K-190, for example).

The rails to be processed before welding are laid either directly on the tracks, or with a slight offset inside the branch or outside the track (at a distance of about 260 centimeters from its axis).

At the same time, the welding mechanism itself moves along the thread being restored, that is, it is a self-propelled rail welding station.

In the process of its operation, replaceable contact heads of various types are used, providing the necessary welding modes (continuous melting or intermittent heating of contacts).

Arc method

Non-contact arc welding is one of the most common methods used when mating the joints of rail threads.

According to this approach, the rails are first laid with a small gap, after which their ends are welded with the metal of the electrodes melted by means of an arc discharge. This type of non-contact welding does not require the application of excess sediment pressure and is realized using alternating or direct currents coming from a mobile welding station.

The most effective way to implement arc welding of rails is the so-called "bathroom" method, according to which the rails cut in advance across the longitudinal axis are laid strictly along the track line with a slight elevation and with a gap of approximately 14-16 millimeters.

Between the ends of the rail blanks laid in this way, a working electrode is inserted, followed by passing a current of about 300-350 amperes through it.

As a result of such an impact, the molten mass spreads evenly over the gap and completely fills it. To prevent it from flowing outward, the gap between the rails is closed with special blocking fences. Upon completion of welding, the resulting seams are ground over the entire joint area.

Thermite processing

The aluminothermic technology has been time-tested. The application of thermite welding of rails is based on a reducing reaction that occurs when the base (aluminum) comes into contact with another component - iron oxide.

The resulting metal (reduced iron) at operating temperatures of about 2000 degrees is poured into a special fire-resistant form that matches the geometry of the welded rails.

This reaction is accompanied by the release of a significant amount of thermal energy.

Welding rails using the thermite method began a very long time ago (since the middle of the 19th century), but since then this type of welding has been called aluminothermic due to the use of aluminum.

It is important to note that the described chemical reaction after the ignition of a special high-temperature fuel (thermite) lasts only a few seconds.

In addition to the two considered components (iron and aluminum oxides), alloying additives and small steel particles are introduced into the composition of the working welded mixture, slightly slowing down or damping the ongoing process. Additives are necessary in order for the steel in the welding zone to acquire the required qualities and parameters characteristic of most rail products.

When considering the features of this type of welding process, it should be noted that upon completion of the reaction, the total chemical mass is divided into two fractions: liquid metal and light slag that floats into the upper part of the mold.

Termitan technology allows to articulate the following types of travel products:

surface-hardened rail blanks;
volume-hardened joining parts of rails,
rails that have not undergone special heat treatment in any combination.

This type of welding ensures compliance with the requirements of the main standards for high-speed rail lines, in terms of compliance with welding technology standards.

Gas press method

This welding technology is based on the connection of metal rail joints at relatively low temperatures (noticeably below the melting limit), but at a sufficiently high pressure.

The main advantages of the gas-pressing method include the homogeneity of the material structure in the welding zone, as well as the high strength of the resulting joint.

Thanks to the listed advantages, this method can effectively “cook” even very heavy and dimensional railway products. Before welding, the ends of such rails are tightly joined to one another, after which, using a special tool (rail cutter with a circular saw or a mechanical hacksaw), they are simultaneously cut.

As a result of the preparatory operations, the required tightness of the fit of the end parts of the rails with a high purity of the metal interface is ensured.

In addition, immediately before welding, the ends are treated with dichloroethane or carbon tetrachloride. At the stage of preparing the rails for welding, their ends are heated to the required temperature by means of special combined burners, which ensure that a sufficient temperature is obtained.

After thorough heating, the ends of the rails are clamped by means of a specially designed hydraulic press and continue to heat up to 1200 degrees.

In the process of welding, the bodies of the burners are slightly displaced relative to the joint being processed (make small oscillatory movements). The frequency of such periodic movements, as a rule, does not exceed 50 oscillations per minute.

Simultaneously with these movements of the gas burner, the rails are compressed by a hydraulic press with a force of 10 to 13 tons, the exact value of which is determined by special calculations. According to the results of such processing, the metal being welded at the junction is deposited by about 20 millimeters.

To implement the described technological chain, special gas-pressing equipment (universal machines) is used.

Upon completion of the entire complex of gas welding operations, the finished joint is carefully cleaned of slags, and then brought to a normal appearance (they say that it is “normalized”).

So, the considered key methods for welding rail joints are applied in accordance with the technical requirements and conditions for carrying out repair and restoration measures.

Of all the approaches, aluminothermic welding stands out as the one that best meets modern requirements for non-contact restoration of rails or laying of railway lines. It is the thermite method that is most often used in the construction and repair of modern transport routes.

Due to the relatively low strength characteristics, this method of welding is rarely used in tram facilities and on station tracks of railways. The advantage of the electric arc welding method is that it can weld rails on the way.

Joints welded by the electric arc method can be divided into two groups: 1) joints with welding of linings and linings; 2) joints welded over the entire cross section of the rails (bathroom method). The joints of the first group are not used in railway transport due to extremely low strength indicators, and they are rarely used in tram tracks.

Bath way '

The bath method for welding rail joints was developed by the Moscow Experimental Welding Plant.

Welding is carried out on direct or alternating current with electrodes with a diameter of 5 mm. Power is supplied from the standard - 76

0 electric welding equipment of STE-34 type; PS-500; PAS-400

Applied current 300-350 a. For welding use UONI-ІЗ/55А brand electrodes with a temporary resistance on - coated metal 55 kg/mm2.

At present, in connection with the emergence of new grades of rail -) steel with increased strength data, it is re - recommended to use UONI-13 / 85u electrodes with temporary resistance of the deposited metal. 85 kg / mm2 -

The assembly of joints for welding, as a rule, is carried out on shpa - iax. The ends of the rails are cut along the square by mechanical means or gas. After cutting with gas, the ends of the rails must be cleaned of scale.

The joint must be aligned in the vertical and horizontal planes, after which it rises by 1.0-1.5 mm per 1 lin. m.

The joint lift is adjusted with wooden wedges, and the check is made with a special steel meter ruler with pins at the ends adjustable in length.

The gap between the welded rails should be 12-15 mm or 1.5 of the electrode diameter, taking into account the thickness of the coating layer. .

Technologically, rail joint welding can be divided into two main operations: base welding, neck and head welding.

* Welding of the sole is carried out on the remaining (steel) or removable copper plate. The length of this plate is 20 mm longer than the width of the rail sole, and the width of the plate is 40 mm.

Several variants of such plates are used:

1) steel (St. 3) 5-6 mm thick; the plate is placed under the joint and pressed tightly;

2) combined, a steel plate 2 mm thick is laid under the joint, and a copper lining under it;

3) a copper plate with a groove filled with several butts of UONI-13/55 A electrodes is pressed directly under the joint.

The best results are obtained by using copper and combined plates. *

The sole of the rail is the most sensitive place of the welded joint, where the low quality of the deposited metal and other welding errors are especially pronounced.

With the bath method of welding, it is important to keep the liquid deposited metal and slag in the inter-butt gap. For this, special reusable copper molds are used: the lower ones are for welding the soles and the side ones are for welding the neck and head.

Outside, the forms have a rectangular shape. Their inner contour corresponds to the shape of the section of the rail with which they are mated. There is a recess along the axis of the mold, which is filled with liquid deposited metal during welding to form a butt reinforcement.

When installing the forms, their axis is combined with the joint gap, and the side forms, in addition, are also fixed with a clamp.

The gap at the junction of the molds with the surface of the rails should not exceed 1 mm. Otherwise, the edges of the molds must be coated with refractory clay. When welding the sole, the seam starts from the edge of the plate and, making oscillatory movements across the joint gap, leads it to the other end, carefully welding the corners between the ends of the rails and the plate.

The second suture should be applied in the opposite direction, also starting from the edge of the plate.

When making the following passes, care must be taken to ensure that the liquid bath of molten metal is located along the entire length of the sole.

During welding, the oscillatory movements of the electrode must be performed quickly. Finish welding of the sole should be in the center of the joint, due to which the seam is obtained with a slope from the center to the edges, which corresponds to the profile of the rails -

In the sole of the joint, the weld should have a reinforcement of 2-3 mm, and the edges of the sole should overlap with a smooth seam.

The surface of the seam after welding the sole must be cleaned of slag.

After the side molds have been installed, the subsequent welding should immediately begin to prevent significant cooling of the joint.

The welding arc is excited at the end of the welding of the sole, i.e., at the base of the neck, and is carried out, continuously filling the entire gap with weld metal.

Finishing the welding of the joint, it is necessary to weld on the tread surface a profitable part with a thickness of 4-5 mm, which compensates for shrinkage during the crystallization of the joint.

After welding, when the joint is still red, its surface should be sealed by forging.

The disadvantages of the bath welding method are hot cracks and lack of fusion. Hot cracks sometimes appear when welding rails made of Bessemer steel containing an increased amount of harmful impurities - sulfur, phosphorus, nitrogen. The same defects can be at acceleration of processes of welding of rails of heavy types.

Lack of penetration and slag inclusions, on the contrary, are obtained at slow welding speeds -

If any defects are found, subsequent welding can be carried out at a joint temperature of at least 300°.

When carrying out installation, as well as repair work on the railway track, crane installations, and other conditions where rails are used, a special welding technology is used. Since, under the described conditions, special strength is required, as well as resistance to various kinds of loads, the welding of railway rails belongs to a separate category of welding.

Arc welding

It should be noted that one of the most common methods used in welding rail strips and rail joints is electric arc welding. In this case, the rails are laid in the required position, and the space between their joints is gradually filled in layers with the necessary welding material. The latter is melted by the temperature of the arc discharge. For welding the ends of railway rails in this way, alternating current supplied from a transformer or direct current obtained from a mobile welding unit can be used.

The best option is the bath method. In this case, the ends of the rails, previously cut perpendicular to their longitudinal axis, are mounted without a fracture. In this case, the profile should have an elevation of 3 to 5 millimeters. In this position, the rails must be fixed with a gap of 14 to 16 mm.

An electrode is inserted between the ends of the railroad rails, through which a current of 300-350 amperes is passed. As a result, the molten metal of the electrode fills the gap between the ends, evenly over the entire cross section.

To prevent metal spreading, various methods are used to close the gap between the rails. After welding, the place of work is polished around the entire perimeter.

Thermite welding

The technology of this type of welding consists in the reaction that occurs when iron oxide and aluminum come into contact. Steel that occurs under the described conditions at temperatures above 2000 degrees must be poured into a fire-resistant mold that is completely identical to the geometry of the rail itself.

Thermite technology was discovered back in 1896 by the famous professor Hans Goldschmidt. In fact, thermite technology is the reduction of iron from oxide using aluminum. In this case, the thermite reaction is characterized by the release of a large amount of heat.

Thermite technology is also called aluminothermic rail welding, as it uses aluminum. Interestingly, the thermite reaction occurs within only a few seconds after the thermite portion is ignited. In addition to iron and aluminum oxide, this mixture includes steel particles that dampen the reaction, as well as alloying additives. The latter serve to obtain steel of the required quality and parameters. Interestingly, at the end of the reaction, a layer-by-layer separation into liquid steel and light slag is carried out, which is on top.

Thermite technology allows connecting surface-hardened, body-hardened, and also non-thermally hardened rails in any combination. Thermite welding makes it possible to meet the high requirements that are put forward today for high-speed highways and jointless tracks.

Gas pressure welding

This technology is based on the connection of metals at a temperature that is in the range below the melting point, but at high pressure. The main "advantages" of this technology:

Homogeneous structure of the metal in the area of the junction of railway rails;
High quality of the resulting connection.

Due to the advantages described above, this type of welding is very effective when welding heavy railroad rails. Before the actual welding, the ends of the railway rails are tightly attached to each other. At the same time, with the help of a circular saw of a rail-cutting machine or a mechanical hacksaw, the ends of both rails are simultaneously cut through. As a result, the maximum purity of the metal is ensured, as well as a high tightness of fit. Before the welding process itself, the ends are washed with carbon tetrachloride. Dichloroethane can also be used for these purposes. The preparatory stage before welding itself consists in heating the ends of the rail, for which multi-flame burners are used.

After that, the ends of the rails must be clamped with a hydraulic press, followed by heating to 1200 degrees using the same multi-flame burners. The latter carry out oscillatory movements along the formed joint. The frequency of these oscillations is 50 oscillations per minute. Along with this, the rails are compressed with a force of 10 to 13 tons, which is set by special calculations. The result is a draft of about 20 mm. To carry out the described actions, universal gas-pressing machines are used.

Processed after completion. After that, it is also normalized.

Results

So, there are three key rail welding technologies. Each of them has its own "pros" and "cons". However, it should be noted that aluminothermic welding meets all the most stringent modern requirements for seamless railway tracks. Therefore, its use is fully justified in the construction and repair of modern highways.

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