What is a weld pool

Bath welding: what is it and technology for welding column reinforcement

Frame-monolithic construction. Actually, nothing more can be said to show the highest demand and bright prospects for welding work with reinforcement structures.

The demand is enormous, technology development is rapid, technical requirements and variety are extremely wide. As a result, there is something to talk about: bathroom welding of fittings.

Application of technology

Reinforcement is an indispensable element of frame-monolithic construction. Reinforced concrete is reinforced with metal rods, from which almost all load-bearing building structures are made: foundation blocks, powerful floor slabs, piles and main beams.

If we talk about household household work, then this is, first of all, a screed made of rods for cement leveling the technical layer of the floor. In such cases, it becomes necessary to connect reinforcing bars. And the most optimal method for this is welding.

This is a strange name

How is the weld pool structured?

Welding of fittings using the bath method. The strange name comes from this: this technology uses molten metal, which is in a limited volume, very reminiscent of a bathtub full of water.

The molten contents of the bath consist of the metal of the electrodes and the ends of the parts being connected. The bath has special linings in the form of brackets to prevent the contents of the bath from spreading during the welding process.

In addition to the brackets, special stops are often placed at the ends of the brackets with the same function - to keep the slag contents from spreading over the rod. These guards are typically made from low carbon steel alloys. After welding is completed, they remain in the seam area.

Baths can be reusable, removable and made of copper or its alloys with the exception of bronze and brass. There are non-metallic baths made of graphite or ceramics.

Welding is carried out with one electrode or a so-called comb - several electrodes connected to each other by a special plate.

The connecting rods with this method can be positioned in any way: vertically, horizontally, or in an inclined position. If the location is horizontal, the bath is formed using a bracket, which is attached at the junction of the reinforcement blanks.

There is some interesting mathematics involved here: the width of the gap between the ends of the reinforcement should be equal to approximately two diameters of the coated electrodes.

If the position of the reinforcing bars is vertical, a stamped metal form is welded to the lower end of the workpiece. After this, it is melted with an arc, the end of the upper rod is grabbed to the lower one, with simultaneous melting of the parts being connected.

Thus, the bath is filled with a mixture of melts. The mold is then burned into the wall to create a hole for the slag to come out. This hole is temporary: after welding, it is welded again.

Features of welding technology

The main difference between this technology and all other types of welding is its continuity. Slag and bubbles with inert gas collect on the surface of the melt in the bath. This is the most important detail of the process, since thanks to this the quality of the butt joint increases dramatically.

Melting of metals occurs using a plasma arc, since the melting temperature must be extremely high.

Bath welding proceeds as follows:

• Ignition of an electric arc using electrodes that close an electrical circuit to generate current.
• An electrode with an ignited arc is drawn slowly and evenly over the edges of the workpiece so that the end of the electrode melts.
• The formed mixture of melts creates a weld pool, in which a new alloy is ultimately formed. The slag and gas bubbles protect the new melt from contact with oxygen and, consequently, the formation of an oxide film.
• The solidification of the new alloy gives rise to a new compound. If everything went correctly, a slag crust is visible on the surface of the seam, which should be smooth.
• The electrode, the end of which melts, must move evenly in the direction of the seam.

Equipment

Thank God, no special equipment is needed here. Bath welding can easily be carried out with a conventional inverter-type apparatus. The distinctive quality of such devices is their ability to provide high frequency voltage, which converts electric current from alternating to direct.

Sometimes, for additional protection of the melt, a special environment of an inert protective gas is created in the bath. In this case, gas cylinders are used.

Single- and multi-electrode welding.

Electrodes are selected from the consumable group. The coating should be made of steel, aluminum or copper alloys. The diameter of the electrode rods is also certain: MP-3 or ANO brands with a diameter in the range of 2 – 4 mm are best suited.

Protective equipment is required: a welder’s mask secured to the back of the head. Overalls and gloves are also necessary to protect against splashes of molten metal and ultraviolet radiation.

Use in construction

Of course, in construction. And primarily for connecting reinforcement - metal rods of any nature. Technically this is difficult: the butt weld is one of the most “unreliable”.

In addition to construction, the welding method is loved and used in the agricultural sector, automotive industry, and in the extractive industries related to gas and oil.

As for everyday household chores, bath seam welding is a completely accessible technology, useful in many places: even at a summer cottage, even in a home garage.

Advantages and disadvantages

Semi-automatic welding methods.

The advantages of the bath welding method are serious:

• There is no need to purchase special equipment; this is a very democratic technology from all points of view.
• Ability to work with any position of joints in space.
• The ability to build an extremely strong frame without the risk of reducing its rigidity.
• Financial efficiency of the method.
• Possibility of use in artisanal conditions.

The disadvantages are more like technical requirements, but we will honestly list them here:

• Since the metal contents in the bath must be in a liquid state at all times, the cooking process must be carried out and maintained continuously. No electrode replacements. Sometimes this is very difficult to do.
• Another strict technological requirement is compliance with precise temperature conditions, otherwise the quality of the seam may suffer.
• Cooling should only be gradual so that there is not too much slag layer.

Source: https://tutsvarka.ru/vidy/vannaya-svarka

Weld pool. What is a weld pool

What isWhat is a weld pool

The weld pool is extended along the seam and has a direct impact on the quality of the weld. A weld made in a weld pool without adding filler material is called autogenous welding.[1]

The heat-affected zone in the weld pool consists of several structural sections that differ in the shape and structure of the grains:

• Incomplete melting zone
• Overheating zone
• Normalization zone
• Zone of incomplete recrystallization
• Recrystallization zone
• Blue brittleness zone.

Incomplete melting - is in a solid-liquid state and determines the quality of the welded joint. In this zone, fusion of the base metal with the weld metal takes place. The temperature in the zone is higher than the melting point of the metal (1500 ° C).

Overheating is an area of ​​the base, highly heated metal with a coarse-grained structure and reduced mechanical properties. In this zone, the formation of hardened structures is possible. Temperatures range from 1100°C to 1500°C.

Normalization is an area of ​​the base metal in which a fine-grained structure with high mechanical properties is formed. The temperature ranges from 930–1100 °C.

Incomplete recrystallization is an area of ​​the base metal in which a fine-grained structure is formed around a coarse-grained structure as a result of recrystallization. The temperature ranges from 720-930 ° C.

Recrystallization is a part of the base metal which is characterized by the restoration of the shape and size of the destroyed metal grains, which was previously subjected to pressure treatment. The temperature ranges from 450-720 ° C.

Blue fragility - there are no visible structural changes, but is characterized by a decrease in plastic properties. The temperature ranges from 200-450 ° C. To improve the properties and structure of the weld metal in the heat-affected zone, hot forging of the weld metal and the part of the base metal that has been heated is used immediately after welding. General heat treatment is also carried out in ovens followed by slow cooling. The width of the heat-affected zone depends on the welding method and modes, and is:

• For manual arc welding - 3-6 mm;
• When welding under submerged arcs - 2-4 mm;
• When welding in shielding gases - 1-3 mm;
• For electroslag welding - 11-14 mm;
• For gas welding - 8-28 mm.

Also, the width of the GTO increases with increasing welding modes and decreases with increasing welding speed.

When welding in an overhead position, the molten metal in the weld pool is kept from flowing out mainly by the force of its surface tension. For high-quality welding, the weight of the molten metal should not exceed this force.

To do this, reduce the size of the weld pool by performing welding with periodic short circuits, allowing the weld metal to partially crystallize.

Reduced electrode diameters are used, the welding current is reduced, and special electrodes are used to ensure a viscous weld pool.

ru-wiki.org

Weld pool - Wikipedia (with comments)

Material from Wikipedia - the free encyclopedia

Weld pool is the part of the weld in a product where the base metal has reached its melting point and where the filler material penetrates. The presence of a weld pool is the key to a successful welding process.

Story

The weld pool was first described by Fouché and Picard while working with oxy-fuel welding in 1903, following the discovery of acetylene by Edmund Davy in 1836.

Properties

The weld pool is extended along the seam and has a direct impact on the quality of the weld. A weld made in a weld pool without adding filler material is called autogenous welding.[1]

The heat-affected zone in the weld pool consists of several structural sections that differ in the shape and structure of the grains:

• Incomplete melting zone
• Overheating zone
• Normalization zone
• Zone of incomplete recrystallization
• Recrystallization zone
• Blue brittleness zone.

Incomplete melting - is in a solid-liquid state and determines the quality of the welded joint. In this zone, fusion of the base metal with the weld metal takes place. The temperature in the zone is higher than the melting point of the metal (1500 ° C).

Overheating is an area of ​​the base, highly heated metal with a coarse-grained structure and reduced mechanical properties. In this zone, the formation of hardened structures is possible. Temperatures range from 1100°C to 1500°C.

Normalization is an area of ​​the base metal in which a fine-grained structure with high mechanical properties is formed. The temperature ranges from 930–1100 °C.

Incomplete recrystallization is an area of ​​the base metal in which a fine-grained structure is formed around a coarse-grained structure as a result of recrystallization. The temperature ranges from 720-930 ° C.

Recrystallization is a part of the base metal which is characterized by the restoration of the shape and size of the destroyed metal grains, which was previously subjected to pressure treatment. The temperature ranges from 450-720 ° C.

Blue fragility - there are no visible structural changes, but is characterized by a decrease in plastic properties. The temperature ranges from 200-450 ° C. To improve the properties and structure of the weld metal in the heat-affected zone, hot forging of the weld metal and the part of the base metal that has been heated is used immediately after welding. General heat treatment is also carried out in ovens followed by slow cooling. The width of the heat-affected zone depends on the welding method and modes and is:

• For manual arc welding - 3-6 mm;
• When welding under submerged arcs - 2-4 mm;
• When welding in shielding gases - 1-3 mm;
• For electroslag welding - 11-14 mm;
• For gas welding - 8-28 mm.

Also, the width of the GTO increases with increasing welding modes and decreases with increasing welding speed.

When welding in an overhead position, the molten metal in the weld pool is kept from flowing out mainly by the force of its surface tension. For high-quality welding, the weight of the molten metal should not exceed this force.

To do this, reduce the size of the weld pool by performing welding with periodic short circuits, allowing the weld metal to partially crystallize.

Reduced electrode diameters are used, the welding current is reduced, and special electrodes are used to ensure a viscous weld pool.

Literature

• Motyakhov M. A. Electric arc welding of metals. M., Higher school, 1975.
• Rybakov V. M. Arc and gas welding. M., Higher school, 1981. 256 p.
• Electric arc welding technology: Textbook / I. V. Gumenyuk, A. V. Ivaskiv, A. V. Gumenyuk. - M.: Certificate, 2006. - 512s
• Theory of welding processes: Textbook. for universities for special purposes “Equipment. and welding technology Produced by V. N. Volchenko, V. M. Yampolsky, V. A. Vinokurov, etc.; Ed. V. V. Frolova. - M.: - Higher School, 1988. - 559 p. ISBN 5-06-001473-8

An excerpt characterizing the weld pool

Since she began following him, he had always experienced this physical sensation of her closeness. She sat on an armchair, sideways to him, blocking the light of the candle from him, and knitted a stocking. (She learned to knit stockings since Prince Andrei told her that no one knows how to take care of the sick like old nannies who knit stockings, and that there is something soothing in knitting a stocking.

) Her thin fingers quickly fingered the occasionally colliding knitting needles, and the thoughtful profile of her downcast face was clearly visible to him. She made a movement and the ball rolled off her lap. She shuddered, looked back at him and, shielding the candle with her hand, with a careful, flexible and precise movement, she bent, raised the ball and sat down in her previous position.

He looked at her without moving, and saw that after her movement she needed to take a deep breath, but she did not dare to do this and carefully took a breath. In the Trinity Lavra they talked about the past, and he told her that if he were alive, he would forever thank God for his wound, which brought him back to her; but since then they never spoke about the future.

“Could it or could it not have happened? - he thought now, looking at her and listening to the light steel sound of the knitting needles. - Was it really only then that fate brought me so strangely together with her that I might die?.. Was the truth of life revealed to me only so that I could live in a lie? I love her more than anything in the world. But what should I do if I love her? - he said, and he suddenly groaned involuntarily, according to the habit that he acquired during his suffering.

Hearing this sound, Natasha put down the stocking, leaned closer to him and suddenly, noticing his glowing eyes, walked up to him with a light step and bent down. - You are not asleep? - No, I’ve been looking at you for a long time; I felt it when you came in. No one like you, but gives me that soft silence of that light. I just want to cry with joy. Natasha moved closer to him. Her face shone with rapturous joy. - Natasha, I love you too much. More than anything else. - And I? “She turned away for a moment.

- Why too much? - she said. - Why too much?.. Well, what do you think, how do you feel in your soul, in your whole soul, will I be alive? What do you think? - I'm sure, I'm sure! – Natasha almost screamed, taking both his hands with a passionate movement. He paused. - How good it would be! - And, taking her hand, he kissed it. Natasha was happy and excited; and immediately she remembered that this was impossible, that he needed calm. “But you didn’t sleep,” she said, suppressing her joy.

- Try to sleep, please. He released her hand, shaking it; she moved to the candle and sat down again in her previous position. She looked back at him twice, his eyes shining towards her. She gave herself a lesson on the stocking and told herself that she wouldn't look back until she finished it. Indeed, soon after that he closed his eyes and fell asleep. He did not sleep for long and suddenly woke up in a cold sweat.

As he fell asleep, he kept thinking about the same thing he had been thinking about all the time - about life and death. And more about death. He felt closer to her. "Love? What is love? - he thought. – Love interferes with death. Love is life. Everything, everything that I understand, I understand only because I love. Everything is, everything exists only because I love. Everything is connected by one thing. Love is God, and to die means for me, a particle of love, to return to the common and eternal source.”

These thoughts seemed comforting to him. But these were just thoughts. Something was missing in them, something was one-sided, personal, mental - it was not obvious. And there was the same anxiety and uncertainty. He fell asleep. He saw in a dream that he was lying in the same room in which he was actually lying, but that he was not wounded, but healthy. Many different faces, insignificant, indifferent, appear before Prince Andrei. He talks to them, argues about something unnecessary. They are getting ready to go somewhere.

Prince Andrey vaguely remembers that all this is insignificant and that he has other, more important concerns, but continues to speak, surprising them, some empty, witty words. Little by little, imperceptibly, all these faces begin to disappear, and everything is replaced by one question about the closed door. He gets up and goes to the door to slide the bolt and lock it. Everything depends on whether he has time or not time to lock her.

He walks, he hurries, his legs don’t move, and he knows that he won’t have time to lock the door, but still he painfully strains all his strength. And a painful fear seizes him. And this fear is the fear of death: it stands behind the door. But at the same time, as he powerlessly and awkwardly crawls towards the door, something terrible, on the other hand, is already, pressing, breaking into it. Something inhuman - death - is breaking at the door, and we must hold it back. He grabs the door, strains his last efforts - it is no longer possible to lock it - at least to hold it; but his strength is weak, clumsy, and, pressed by the terrible, the door opens and closes again.

wiki-org.ru

Welding bath - What is a welding bath?

Welding pool is a zone of a welded joint that is in a molten state during the welding process.

[Terminological dictionary of construction in 12 languages ​​(VNIIIS Gosstroy USSR)]

Welding pool - part of the metal of the welded seam, which is in a liquid state during fusion welding.

[GOST 2601-84]

Category: Welding

Source: https://katlavan.ru/chto-takoe/chto-takoe-svarochnaya-vanna.html

Bath welding of reinforcement: principle and technology of the bath welding method, their brief description

Bath welding of reinforcement is a method of joining metals using a special bracket-plate, which is also called a bath for welding reinforcement. The method is used in the formation and connection of reinforcing bars, as well as for reinforcement joints.

State standards

For this construction process, a GOST was developed called “Joints of welded reinforcement and embedded products of reinforced concrete structures.” The standard was introduced on July 1, 1992 under the number 14098-91.

Bath welding is a reliable and commonly used method. A distinctive feature of this process from all other types of welding is its continuity, which is very important for uniform melting. Thanks to this process, the metal melts much faster.

The welding method is used in the construction of various massive structures and buildings. The seam created using this welding is capable of withstanding moving loads without destroying the integrity of the structure and meets the requirements of GOST. If conventional butt welding is carried out, it can lead to failure of the joint near the seam, thus significantly degrading the quality of the weld.

Process Highlights

The essence of the process is this: the ends of the reinforcement rods to be welded are located inside the bath, then they are melted one by one with electrodes. The electrode should touch the rod slightly , since welding is carried out at high current power.

Welding is carried out using one or more connected electrodes.

You can make the bracket-plate with your own hands or use existing molds that were produced in a factory by stamping. The manufactured form is welded to the electrodes to be welded.

Welding principle

The principle is as follows:

• the steel form should be welded to the reinforcement bars in the connection area;
• then the electrode forms a melt zone using the heat of the arc;
• since the ends melt from the heat of the bath metal, resulting in a liquid structure;
• As a result, upon cooling, a welded joint is formed.

The connecting rods can be positioned in any way: horizontally, vertically and in an inclined position. If the rods are located horizontally, then in this case the bath must be formed using a bracket, which is attached at the junction of the reinforcement blanks. Vertical joints are welded using a stamped form.

Basically, the bath welding process is used to connect rods with a large cross-section of 20-100 mm, since this size scale is most suitable for making a high-quality seam.

Types of bath welding:

Methods of bath welding of reinforcement and their brief characteristics

The most common and most used are single-electrode and multi-electrode welding methods.

Single electrode method

Single-electrode arc welding can be performed with an arc powered by alternating or direct current. This method is used when assembling structures that are under the influence of stationary loads.

You must first prepare the surface. To do this, the ends of the steel reinforcement should be cleaned of various dirt, rust and dust; this can be done using iron brushes.

Bath welding begins from one side, gradually moving closer to the center. Select the correct angle of inclination for each position of the seam in space and type of joint. The further formation of the weld pool depends on the angle of inclination of the electrode. By choosing the correct angle of inclination, the cavity of the bath will be evenly filled, and the base metal will warm up.

When melting, the electrode is lowered, creating a particularly short arc. The metal, completely covering the fittings, rises to the upper edge of the bath. Thus, the welding is considered complete. The parts should be adjusted after the seam has cooled.

When stopping welding, it is imperative to beat off the slag and light an arc at the finished edge of the seam. It will be possible to reliably cover the place where the seam stops and breaks. The seam should be completed in the middle of the bath to prevent holes and voids. Such places must be cleaned of slag and this procedure must be repeated about five times.

Multi-electrode welding

The multi-electrode welding method operates on the same principle as the single-electrode method. It is best to finish the seam in the middle of the overlay.

This method guarantees high productivity of the process and the quality of the smelted metal, reduced penetration and distortion of parts, as well as a reduction in specific heat input.

Equipment used

Welding of reinforcement can be carried out if the following equipment and materials are available:

• single-phase or three-phase welding machine 220 volts , providing direct current;
• trays (brackets) . They should be selected in accordance with the seam and the nature of the products being welded;
• limited volume cylinders with inert gas;
• consumable electrodes coated with various alloys;
• necessary special-purpose clothing to protect against UV rays and splashes of liquid metal. A protective mask is also required.

Approximate cost of welding machines on Yandex.market

Advantages and disadvantages of the method

Bath welding has a number of advantages:

• Throughout the melt, the rods are uniformly heated;
• for each rod it is quite easy to choose shapes for its size , since they are available in a large assortment;
• Generally available welding equipment is used for work.;
• minimal costs for consumable materials;
• no need for edging structures;
• by using gamma radiation it is possible to check the quality of welding.

There are also some disadvantages:

• constant adherence to precise temperature conditions . It is necessary to ensure that the quality of the seam is not affected;
• high cost of copper baths that are used many times;
• Steel baths can only be used once;
• a large number of steel baths are consumed;
• mandatory preparatory stage , which takes a lot of time;
• Cooling must occur gradually so that a large amount of slag layer does not form.

Source: https://elsvarkin.ru/texnologiya/vannaya-svarka/

What is a weld pool?

Various types of reinforcement are a fairly popular building material for frame house construction. Piles, foundation blocks, beams, and floor slabs are made from reinforced concrete reinforced with metal rods.

Reinforced concrete is also very often used for the construction of foundations, basements, building walls, lintels for window and door structures, balcony slabs, interfloor stairs in high-rise residential buildings. Steel rods are used to strengthen the floor screed.

When using fittings in domestic conditions, they have to be connected to each other. The best way for this is the tubular technology of welding reinforcement.

Specifics of technology

The connection of individual metal elements in a weld pool is most often used for reinforcing rods with a diameter of no more than 100 mm, for butt flanges obtained by bending strips of large-section metal, welding multi-row reinforcing rods, and other parts. This method of welding parts is also used in the process of constructing metal frames from reinforcement, residential buildings, and industrial buildings.

In order to obtain the desired high-quality result when performing welding work, it is necessary to accurately maintain the displacement of the outlets, when the parameter of displacement of the axes of the welded rods is allowed up to 0.05 parts of the diameter of the workpiece.

To comply with this parameter in connections with the combination of the reinforcement frame, it is necessary to work in conductors specially designed for this purpose, which provide for fixing the position of large steel rods.

When accepting parts, the dimensions and location of fittings must be checked.

Advantages of using bath welding technique

1. Possibility of using standard tools designed for electric arc welding to connect metal samples.
2. There is no need to constantly rotate the welded structure during the work.
3. Possibility of quality control of seam joints.

Today, technologically, the following types of welding are distinguished:

• automatic slag in the weld pool;
• semi-automatic bathroom;
• manual bathroom in a bracket with a single-, three-phase arc.

The most economical option is to weld reinforced concrete rods without using special overlays. And due to the inconvenience of embedding overlays into the sections of rods, this technique provides the opportunity to significantly save in terms of additional costs for material and production of overlays, and also reduces labor costs.

Bath welding of reinforcing bars

A similar connection technique is used:

• when connecting steel rods with a diameter of 20–100 mm;
• for welding reinforcing bars in reinforced concrete products;
• for connecting flanges made of large-section metal strips.

This technique has shown itself to be excellent in the process of welding parts of large reinforced concrete structures, during the construction of residential buildings and industrial buildings. When welding an integral frame made of reinforcement, this technology guarantees high strength and rigidity of the structure along the entire length. This type of welding work can also be carried out from a variety of angles: vertically, horizontally, at an angle. This makes the work much easier.

Features of the technique

Welding of reinforcement rod outlets is carried out in several options:

• end-to-end;
• using special pads.

Butt welding

In this case, a weld pool is used. The following types of welding are used for connections:

• bath-suture;
• manual, in inventory forms;
• coated electrodes;
• multilayer flux-cored wire using special linings;
• flux-cored wire with a flux core;
• submerged wire (semi-automatic).

The connection using special overlays is carried out using electric arc manual welding.

The welding technique using a weld pool makes it possible to obtain high-quality connections, strong, rigid metal frame structures along their entire perimeter. Thanks to the ability to perform work in any plane, the technology is one of the most popular in the construction industry today.

Source: https://electrod.biz/accessories/chto-takoe-svarochnaya-vanna.html

Bathtub welding of fittings: what it is, methods, technology features

Welding has long been firmly established in many areas of industry. This type of metal connection makes it possible to create huge structures of special importance, various equipment, and instruments that are necessary for our lives. Each method has advantages and disadvantages, but we will focus on a reliable welding method that is popular in many industries - bath welding.

It is used for welding individual parts of alloy steel products. This method is able to withstand increased static and dynamic loads. But still, before starting it, it is worth considering the main features and nuances.

a brief description of

Bath welding is a method of welding metal products that uses a U-shaped fixture. It has several names - trays or bracket plates for welding reinforcement. This formed the basis for the name of this welding method. Parts of the reinforcement are immersed in the bracket-tub, molten steel fills it to the brim. After this, the metal hardens and forms a seam with high strength.

To prevent molten steel from flowing out from the ends of the bath, restrictive elements are placed. And at the end of the welding process, the pools are combined with reinforcement and molten steel. There are removable linings that are made of copper, its alloys, ceramics, and graphite. These options are intended for repeated use.

Bath welding of reinforcement can be carried out using one or more electrodes. This welding method allows you to weld metal elements in any position in space, except for the ceiling. The size of the lining must be larger than the diameter parameters of the reinforcement. There should be at least 15 mm from the edges of the bath to the element being welded.

If the products are in a horizontal position, then to create a bath, a steel plate is welded to the connecting reinforcing bars in the area of ​​their junction. When welding rods that are in a vertical position, stamped steel forms are used. They are welded to the end area of ​​the product, which is located below.

Features and nuances of the welding process

Welding reinforcement using the hot tub method has several additional features that must be considered before starting work. This technology is considered a simple process, but still, if you want to get a high-quality and durable connection, you should prepare carefully.

Bath welding has the following features:

1. The welding process must be carried out continuously. This makes a huge difference in achieving an even melt. The fact is that the temperature indicators of some types of metals are quite high; it takes a lot of time to warm up. Due to the fact that welding work is carried out in a continuous mode, the steel melts much faster.
2. Bubbles of slag and protective gas form on the surface of the metal product. To let them out, you need to make a hole in the bath. But still, slag formations are not considered foreign components; they protect the seams from oxidation.
3. The technology of bath welding of reinforcement involves the appearance of a protective crust on the joint surface. Usually its formation indicates compliance with all the rules of the welding process.
4. Immediately after welding is completed, there is no need to peel off the protective crust; you need to wait until the molten metal hardens. In the meantime, while the part is hot, you can lightly tap it on all sides, this will eliminate the increased stress.
5. When welding, the electrode should not be held motionless at the joint area. Beginners think that this will ensure that thermal energy can independently disperse over the surface of the product and the steel will melt evenly. During the process, the movements must be consistent, and at the same time the welder must capture unmelted edges.
6. The workflow speed should not be too slow or too fast.
7. If the welder does everything too quickly during welding, he will not be able to melt the metal to the required temperature, and the joint itself will be of poor quality.
8. If the welder is slow, he will not melt the steel evenly. As a result, it will be distributed in the bath so that the finished seam will turn out to be of poor quality. The optimal welding speed is indicated in GOST standards.

Advantages

Pool welding is a simple and easy method of connecting sections of metal structures. This technology is used in many areas of production; it allows you to work with different types of metal.

Bath welding of reinforcement and columns has a number of advantages:

• this method can be used for fixed parts of metal structures. There is no need to rotate and move them to create a strong connection over the entire surface;
• during the melt, uniform rather than spot heating of the rods occurs;
• examination of the seam can be performed using available methods, for example, using gamma-ray diagnostics;
• Conventional equipment can be used for the work process;
• welding using this method allows you to obtain a strong and high-quality connection;
• baths for welding reinforcement prevent the spreading of molten material, they form a neat and even seam;
• minimal costs for consumables;
• maximum convenience that facilitates welding. And the steel form serves as an additional stiffening rib;
• You can quite simply select the shapes to match the dimensions of the rod. They are available in a wide range.

Flaws

But it is still worth remembering that welding reinforcement using the hot tub method is not just an easy method of obtaining a strong connection; this process has some disadvantages that should be taken into account when carrying out welding work.

Among the negative aspects are:

• When carrying out the welding process, continuity of work must be observed;
• you need to ensure that the heating covers the entire contact area;
• This welding method requires professional training;
• usually welding pools are used only once, they are not intended for repeated use;
• The preparatory stage must be followed, and this is an additional time investment.

Important! If the required temperature conditions are not observed during the welding process. If cooled too quickly, too much slag may form.

Equipment used

We have looked at what it is - hot tub welding, but you still need to know what equipment should be used during this process. This is an important condition on which the quality and strength of the welded joint depends.

Typically, the following elements are used during bath welding:

1. Welding machine. This element reduces the voltage to 220 volts and produces direct current with great strength. It is called a welding inverter; it has a full range of functions and modes. Currently, small-sized devices are being produced that can be used at home.
2. Overlay brackets for welding reinforcement. These products should be selected in accordance with the type of connection and the nature of the elements being welded. For horizontal ones, it is recommended to use options such as C14-Mn, C15-Pc, C16-Mo.
3. To protect the molten metal in the weld pool, in some situations it may be necessary to create an environment of inert gas; this is usually required by the quality of the materials being welded. For these purposes, it is recommended to use small cylinders with inert gas, which are commercially available.
4. Consumable type electrodes. They can have different coatings made of aluminum, copper, steel and other alloys. For ordinary work, rods of the MP-3 or ANO brands are suitable; their diameter should be within 2-4 mm. These consumables can always be found on sale. But only SSSI rods are suitable for critical equipment.
5. Welder protective mask. The most suitable option for welding work would be a product that is mounted on the head. Additionally, you need clothing and gloves made of protective material. Products must be protected from ultraviolet rays and splashes of molten metal.

How is bath welding carried out?

The technology for bath welding of reinforcement and columns consists of several stages. During the first step, all materials and parts to be welded are prepared. And in the next stage, the main welding work is carried out.

There are a few things you should do when preparing:

• Cleaning the ends of the reinforcing bars with a wire brush until shiny. During this stage, it is worth removing all areas with rust, dirt, paint and other types of contaminants. All this can deteriorate the quality of the connection, making it brittle and weak. The clearing size at each end should be at least 3 cm;
• an inverter mold must be spot welded to the lower planes of the joining rods. It will serve as a container for accumulating molten steel.

After this, you can begin welding the columns and fittings. The electrode needs to be brought to the end of one of the rods and begin to melt it. The consumable needs to be moved over the entire area of ​​the end - movements can be circular or from side to side. Afterwards you can move to the opposite end of the reinforcement being welded. Actions should be carried out one at a time until the bath is completely filled with molten metal.

It is worth noting! All actions and movements during the welding process should be light, because melting occurs at high currents. For example, if electrodes with a diameter of 7-8 mm are used, then a current of 400-450 amperes should be applied to them.

Welding must continue until the molten metal covers the rods being connected. After this, it is recommended to carry out the final steps correctly - you need to once again evenly heat the metal in the weld pool, this is necessary for its uniform cooling. Next, the electrode is rotated between the ends of the reinforcement being connected, but this should not be done too much.

Bath welding process is a popular method that is used in various industries. It allows you to get a strong, high-quality and even connection, and this is achieved through the use of pad brackets for bath welding, also these elements are called baths. They also prevent splashing and flow of molten material from the welding zone. But still, before carrying out work, it is worth considering its important features and principles.

Interesting video

Source: https://osvarka.com/vidy-i-sposoby-svarki/vannaya-svarka-armatury

Bathtub welding fittings

Reinforcement, as an element of a frame structure, is used in many building elements, assemblies and blocks. Its main purpose is to give the building structure rigidity and increased tensile strength. To assemble a reinforcing frame from reinforcement, steel rods are either tied together or welded. The second option is most often used for large volumes of construction. And it is divided into two different technologies: bath welding of reinforcement and welding with overlays.

Welding reinforcement using the bath method is more economical compared to welding using overlays. Depending on the cross-section of the steel bars used, savings amount to 10-60 kg of reinforcement and 0.5-2.5 kg of electrodes. In addition, when welding, there is no need to rotate the structure being welded for ease of the joining process.

Bath welding technology

The technology is based on the process of melting steel reinforcement, the liquid metal of which flows down and is collected in a special form, it is called a bath. A mold is made from a low-carbon steel sheet and tack welded to the electrodes to be welded. You can make a bath with your own hands, or you can use ready-made molds that are made in a factory by stamping.

Depending on the volume of welding work performed, three types of pool welding can be used.

1. Manual welding using a steel mold (bath). The welding process can be performed with a single-phase or three-phase arc.
2. The use of semi-automatic machines using molds made of graphite.
3. The use of automatic welding machines using molds made of copper.

Manual welding

This technology is usually used when connecting steel reinforcing bars with a diameter of 20-100 mm. To do this, you need to very accurately align the two rods on the same axis. Their displacement relative to each other should not exceed half the diameter of the reinforcement itself. That is, pool welding is a butt connection of two reinforcements.

What other requirements are imposed on the welding process?

• Welding is carried out only on the cleaned ends of the reinforcing bars. They must be cleaned with an iron brush to a metallic shine at a distance of 3 cm from the edges.
• A small gap is left between the rods, no more than one and a half diameters of the electrode used. With a three-phase arc, the gap can be twice the diameter of the electrode.
• The bath is welded to the bottom surface of the reinforcing bars being welded. That is, with its shape it creates a kind of reservoir where the molten metal will collect.
• When using a three-phase arc for welding, in addition to the bath itself, it is necessary to install side limiters so that the molten metal and slag do not spread over the rods being connected.

This is how parts of steel reinforcement located in a horizontal plane are usually welded. Vertical docking is done in exactly the same way, only with some additions. For this, only a stamped bath is used. It is welded to the lower rod. A limiter is installed at its lower end. When removing slag from the welding zone, a hole is made in the lower limiter with an electrode, which is welded after removing the slag.

Bath Welding Process

After all the preparatory work has been carried out, you can proceed directly to the welding operation. It all starts with the initiation of an electric arc, which appears after the electrode begins to touch one of the reinforcing bars.

The touch should be light, because the process of melting the metal occurs at high current values. Namely: if welding is performed with electrodes with a diameter of 5-6 mm, then the current used for the connection should be 400-450 amperes.

If the welding process is carried out at low temperatures, then the current will have to be increased by 10-15%.

So, the arc has been ignited, now you need to melt the end of the reinforcement on which the arc was lit. As soon as molten metal appears in liquid form at the bottom of the bath, the melting is transferred to the second reinforcement rod. And in this way it is necessary to melt the steel rods one by one. In this case, the electrode must perform oscillatory movements, both along the joint and across.

It is necessary to pay attention to the filling level of the bath. As soon as the liquid metal covers the rods, you need to make circular movements with the electrode between the rods to be welded. This will ensure uniform heating of the liquid metal before cooling. There is no need to rotate the electrode too much. After which you can complete this welding process.

It is clear that this operation cannot be carried out with one electrode, so it is recommended to quickly change consumables. The welder must have time in 5 seconds to remove the remains of the old electrode, and pull out the new one, and install it in the clamp.

Welding baths

A few words about baths for fittings. As mentioned above, three main types are currently used, differing from each other in raw material. But they also have other differences. For example, a steel form is a permanent part that remains in the reinforcement structure and is then poured with concrete along with the rods.

Copper and graphite baths are detachable products that, after completing the welding process, are removed from the junction of two reinforcing bars. After which they can be reused.

The turnover rate of copper molds is almost twice as high as that of graphite molds. It should be noted that graphite itself is a hygroscopic material, that is, it easily absorbs moisture, even in the air.

Therefore, before use, the graphite mold must be calcined, thereby removing excess moisture.

You can weld reinforcement using the bath method using more than just one electrode. There is multi-electrode welding technology. For this, a special tool is used - a comb, into which several electrodes are installed. It is difficult to ignite the arc of several consumables on the reinforcement rods at once, so they are ignited on the bottom of the bath. Everything else happens in exactly the same way as in technology with one electrode.

As soon as the mold is filled with molten metal, you need to install the comb so that the electrodes are directed perpendicular to the plane of the filled bath and located in the middle between the reinforcing bars to be welded. After which they need to be immersed in molten metal for 2-3 seconds and pulled back out. This movement should be carried out 8-10 times. This will allow the metal to be evenly heated until it cools.

Bath welding can be carried out without baths, for which linings from the same reinforcement are used. This option is rarely used, only in cases where it is impossible to carry out the welding process in special forms.

Be sure to check out the video posted on this page of the site, which shows the process of welding reinforcement using the hot tub method.

Source: https://svarkalegko.com/tehonology/svarka-vannym-sposobom.html

Welding of fittings using the hot tub method

To strengthen concrete, metal reinforcement of different sizes is used. The reliability of foundation and load-bearing wall structures, tunnels, and bridge supports is ensured by frames made of reinforcement. They are filled with a cement-based mortar to form reinforced concrete. There are various technologies for connecting steel bars.

Bath welding is considered the most reliable and often used; the seam obtained by this method is capable of withstanding large static and dynamic loads without compromising the integrity of the structure, and meets the high requirements of GOST 14098 in force in civil engineering. Rails and thick-walled alloy steel are connected by hot-welding. This high-temperature metal joining method is used in many industries.

Methods for connecting reinforcement

In construction, there are several technologies for producing solid reinforcing bars.

The mechanical method of connecting joints involves the use of pressed couplings or pipe sections. A hydraulic press is used to fix the joint by crimping.

To speed up the process, couplings with a partition are made; it is simply put on the rod, and the next one is inserted into the other end. The weight of the structure and the metal consumption of reinforced concrete increase with this method of fastening reinforcing bars.

Couplings must be selected according to the standard size of the reinforcing bar; for the press, a replaceable die is made for each size.

Steel bars of classes A400 and AIII are overlapped together using special claws, using tying wire and standard hooks. The mechanical joining method is used only because rods of these brands cannot be welded.

Among the high-temperature methods for producing permanent joints, the most reliable is welding of reinforcement using the hot tub method. During the formation of the joint, longitudinal cracks, characteristic of multi-seam welding, do not form. The technology of hot joining using a pad for welding reinforcement is metal-intensive, the cost of materials increases by 5-7%. When butt welding rods, a too brittle joint is formed that does not have the required strength.

The principle of pool welding

The bath welding method is used for metal strips with a cross-section of up to 50 mm, fastening thick-walled flanges, and joining rods. The diameter range of the reinforcement is from 20 mm to 10 cm.

Bath welding classification:

• manual arc with outlets placed in a steel bracket;
• semi-automatic, the weld pool is formed in a ceramic form, in this case the cost of overlays is eliminated, electrodes are saved, and a neat joint is formed;
• bath-slag, it uses a mold made of copper-containing alloys.

When constructing metal frames of reinforced concrete foundations, load-bearing walls, tunnels, and supports, joining of reinforcement is often done manually. What is it from a technology point of view: forced formation of a tight seam at the junction of two rods.

Source: https://svarkaprosto.ru/tehnologii/svarka-armatury-vannym-sposobom

Bath welding technology for reinforcement

All construction processes have state standards that determine how they should be carried out. The standards clearly indicate what materials should be used, what technologies and the sequence of operations performed. Welding of reinforcement is no exception.

How two reinforcement rods are connected by hot welding

For this construction process, a GOST was developed called “Joints of welded reinforcement and embedded products of reinforced concrete structures.” The standard was introduced on July 1, 1992 under the number 14098-91. It contains two tables that define the requirements for bath welding of reinforcement, the topic of which is in the article.

1. In the table, number “1,” the types of reinforcement welding are indicated: butt, cross, tee and lap. The butt category includes welding using a bath or in another way: inverter form. That is, in this way you can weld reinforcing bars installed end-to-end.
2. Table No. 30, called “Terms and Explanations,” gives the concept of reinforcement welding using the pool method. The table says that pool welding is a process in which the melting of the joined rods occurs mainly due to the heat of the molten metal pool.

Notice the word - mostly - which suggests that it's not just the molten metal that melts the reinforcing bars. Therefore, we will thoroughly understand the technology of welding reinforcement using the bath method.

The final result of pool welding

Requirements for bath connection technology

Let's start with the fact that bath welding of reinforcement is a process in which, in addition to electrodes and a welding machine, a special device with a U-shaped cross-section, made of low-alloy steel by stamping, is used. This is the first.

Secondly, the dimensions of the bath are determined by the diameters of the joining fittings. The only standard value is the thickness of the steel used to make the bath, equal to 6-8 mm. Let’s make a reservation right away that the device is disposable. When welding is completed, it remains at the site where the reinforcement is joined, as an integral part of the connection. Thus, the bath further strengthens the joint.

Steel inverter molds

It should be added that in addition to steel inverter molds, when welding two reinforcing rods, copper or graphite are used. Both options are reusable, that is, after finishing the work, the baths are removed, cleaned, and can be used again at another joint. This is a big plus, but these forms have a big minus - the high price. Therefore, most often builders use steel forms.

The third requirement is that the two ends of the reinforcement are joined along one axis with a tolerance within half the diameter of the rods. The gap between the ends is no more than 1.5 times the diameter of the reinforcement. In this case, bath welding of reinforcement can be used both at a horizontally located joint and at a vertically located one.

Attention! In the latter case, a steel limiter is added to the bath, which is welded to the mold from below. It is this that prevents the molten metal from flowing out.

Fourth, rods with a diameter of 20-100 mm can be connected using this method if manual welding is used.

The fifth requirement concerns welding methods. There are three positions here:

• manual,
• automatic (special welding equipment is used with automatic electrode supply and movement of the electrode holder),
• semi-automatic (movement of the holder is manual, electrode supply is automatic).

Preparatory process

This includes two operations:

1. Clean the ends of the reinforcing bars with a wire brush until shiny. The main task is to remove areas of rust, dirt, paint and other materials that interfere with obtaining high final quality. Clearance size is 30mm (minimum) at each end.
2. Spot weld the inverter mold to the lower planes of the joined rods. It will create a container in which the molten steel will collect.

Main stage

It should be noted right away that the main metal that will fill the bath is reinforcement steel. Therefore, the electrode is brought to the end of one of the rods and they begin to melt it, moving the consumable over the entire area of ​​the end: in a circular motion or from side to side. Then the work moves to the opposite end of the reinforcement being connected. And so on one by one until the bath is completely filled with molten metal.

Attention! All movements should be light, because melting is carried out at high currents. For example, if electrodes with a diameter of 7-8 mm are used, then a current of 400-450 amperes is supplied to them.

Welding of the reinforcement continues until the molten steel covers the rods being connected. The work does not end here; the final manipulations must be carried out correctly in order to uniformly once again heat up all the metal assembled in the mold so that it cools evenly. The electrode is simply rotated between the ends of the reinforcement being connected, but not much. Now you can complete the welding process.

Even the smallest bath cannot be filled with metal if one electrode is used for melting. At a minimum, 4-5 consumables will be used up. Therefore, the welder who performs this type of welding must have experience and skills, where the main thing is the speed of replacing electrodes. No more than 5 seconds are allocated for this. After this time period, the steel will simply begin to harden. And all the manipulations done are zero. Unevenly cooling metal means a decrease in the quality of the connection.

Welding with a comb and several electrodes

This method is called multi-electrode welding, which uses a special holder called a comb. Several electrodes (3-5 pieces) are inserted into it at once. The principle of melting the reinforcement here is exactly the same as in the case of one consumable. But it also has its own characteristics.

1. The arc of electrodes is ignited not on the fittings, but on a metal tray, often on its bottom. You just can’t ignite several electrodes at once on one end.
2. To strengthen the joint, the electrodes are periodically dipped into the molten metal to warm it up.
3. You can not leave a gap between the reinforcement bars, pressing them tightly against each other.
4. When the fittings are positioned vertically, do not strongly deviate the electrodes from perpendicular to the connection axis.

This method is rarely used when connecting reinforcement inside concrete structures. It is not easy, and not all welders know it. It is better to use split molds made of copper or graphite for this, which increases the cost of the process.

Single- and multi-electrode pool welding

Welding mode

Bath technology for joining reinforcement is most often used for joining large diameter rods. Therefore, the welding mode is one of the important criteria for achieving high quality joints. The mode includes: electrode diameter, current strength, and all this depends on the diameter of the reinforcing bars being welded. The dependency here is:

Diameter of fittings, mm	Electrode diameter, mm	Current strength, A
20-25	5	230-260
36, 45	6	300-330
60	7	420
70	8	500

Since welding of this type involves the use of high currents, an important component of the process is safety precautions. It is important before starting to connect the reinforcement using bath welding to make sure that the equipment, tools and fixtures used are in technically sound condition. Much attention should be paid to grounding, special clothing and a welding helmet. Welding sites must be equipped with primary fire extinguishing equipment.

Advantages and disadvantages of tub welding of reinforcement

The advantages include:

• rational consumption of raw materials;
• high quality connection;
• sophisticated technology that allows you to achieve high quality;
• a variety of inverter shapes, which allows you to make a choice exactly according to the dimensions of the fittings.

Negative aspects of technology:

• more demanding preparation that takes a lot of time, especially with regard to the precise alignment of the ends of the two reinforcing bars being connected;
• high consumption of steel baths;
• high price of copper molds.

So, this method of connecting reinforcing bars, if carried out correctly, results in a high quality final result. The seam is strong and reliable. The joint is flexible, like solid reinforcement, which allows it to withstand bending loads.

Source: https://viascio.ru/materialy/armatura/tehnologiya-svarki-armatury

Bath welding: what it is, how it is performed, features of the technique and where it is used

At the moment, there are more than a hundred types of welding. There are many distinctive features between them.

However, what is common to all is that the connection is obtained by melting metal parts.

In order to correctly select the required type of permanent connection, it is necessary to take into account the characteristics of the products that are planned for joining.

In this publication we will talk about the welding technique.

General information

In particular, the welding method is often used for welding reinforcement parts (also called “butt welding”).

Here we will highlight the technological processes of pool welding using semicircular staples and the features of working with reinforcement. This method can also be used for welding steel structures.

It should be noted that when welding the reinforcement parts of columns, the most commonly used method is butt welding.

Bath welding is carried out by joining metals using special horseshoe-shaped strips, which are called “welding baths” or “welding pad brackets.”

This technology gets its name from the devices that are used in it. The essence of this method is that the ends of the reinforcement are placed in the bracket-tub and filled to the brim with molten metal.

After the metal hardens, a strong connection is formed.

Usually, additional limiting devices are installed to prevent metal from flowing out from the ends of the bath. Low carbon steel is usually used to make tray brackets.

After using these curved strips for welding joints, they are fused together with reinforcing bar and molten iron.

But there are staples for repeated use using the bath method, which are made from copper alloys, ceramics or graphite. They are more convenient and practical.

Features of the technology

For the process of obtaining permanent connections, one or more electrodes are used. You can connect reinforcing bars using the pool welding method in any position except for the ceiling.

But for this you need to adhere to certain parameters.

For example, the diameter of the reinforcing bar should be smaller than the staple. The distance to the rod from the edges of the bracket is allowed from 1.5 centimeters.

There are also certain features of welding joints using the bathtub method in a vertical position.

To do this, take a curved iron strip made of steel (disposable) and weld it to the part located below. The lower end of the reinforcing bar is melted and then the upper part of the reinforcing bar is joined to the lower machined end and the joint is melted.

The bracket is slowly filled with molten iron. Sometimes, to avoid the formation of a large amount of slag, a small hole is made in the bathroom. At the end of the process, it is also brewed.

Butt method

The butt welding method, like any full-fledged technology, has a number of its own nuances and certain features that must be taken into account in the work.

Firstly, this method requires continuity of the process. This is what guarantees uniform melting, since the melting temperature of many groups of metals is very high and requires a long time period.

And with a continuous process, metal parts melt much faster.

Secondly, as mentioned earlier, slag bubbles may appear during bath welding. It is precisely to prevent them from accumulating and coming out that a small hole is made in the bracket-bath.

It is important that on the metal surface they perform the function of protecting the compound from oxidation. After hot welding, a protective crust forms along the top of the seam on the reinforcement.

It is evidence that the work was done correctly, in compliance with the necessary technology. When the temperature of the metal drops, this crust can be cleaned off.

While the part is still hot, you can tap it a little to remove excess stress.

When using an electrode in the welding process, professionals do everything with translational movements, while grabbing unmelted edges.

It would be a mistake to keep the electrode motionless at the joint, since thermal energy cannot be distributed independently, and as a result, the metal elements melt unevenly.

All actions must be performed without haste, but also without delay.

If welding is too fast, the metal may not have time to melt and acquire the required temperature, and as a result, even a seemingly good connection may turn out to be of poor quality.

If you work too slowly, the metal will melt and spread unevenly throughout the bath, and the connection may end up being brittle and porous. There are GOST standards that indicate the appropriate speed for creating permanent connections.

Butt welding with bracket

Bathtub butt welding does not require any special equipment. A welding machine that is capable of delivering powerful welding current and operating from a regular household outlet is sufficient.

A small household welder or any other inverter in the mid-price range can even handle this task.

Separately, it is necessary to purchase bath brackets, taking into account the type of connection required and the characteristics of the part itself that needs to be welded.

For connections in the horizontal plane, the most common are bathroom brackets C-14-Mn, C15-Pc and C16-Mo.

In this case, the length of the bracket-tub should also be taken into account, since the volume of welded metal directly affects the quality of the connection. When choosing a suitable bath, you need to pay attention to its melting point.

It must be higher than the melting temperature of the reinforcement part itself.

The methods used for connecting metal structures by welding can be combined. Butt welding using bath technology can be used in parallel with methods that use gas.

To do this, you will need a cylinder with argon or other inert gas. In addition, coated consumable electrodes, for example, MP-3 or ANO, can be used for the welding seam.

This is especially important for beginners. Taking into account the thickness of the metal, the appropriate diameter of the electrode is selected. A good option for more experienced welders would be consumables from the UONI brand.

Conclusion

When performing welding work, it is recommended to use special equipment for personal protection: masks (a chameleon mask would be a good option), overalls, gloves and shoes with non-conductive soles.

This is all necessary primarily for the safety of the welder himself.

In conclusion, I would like to say that the method of butt welding using staple trays is reliable and quite simple in its technology. It can be used by novice welders without experience or special qualifications.

If you understand the very essence of this method and watch videos on the Internet, then basic skills will be enough. We hope that this article was useful to you!

Source: https://prosvarku.info/tehnika-svarki/vannaya-svarka

Features of the bath method of welding reinforcement

Bath welding of reinforcement is the most reliable method of connecting individual sections of metal structures made of high-strength alloy steel. The welding result is influenced by a number of factors, one of which is the alignment of the joined sections.

When carrying out conventional butt welding, the quality of the seam will be unreliable, the connection will break near the seam. Therefore, a solution has been developed for a more durable connection of the longitudinal and transverse sections of the reinforcing mesh - the pool welding method. Under significant loads during operation, the structure has sufficient rigidity, and the welding seam on the connection is small.

The essence of the process

The pool welding method is most often used to connect rods with a large cross-section of 20 - 100 mm. This range of sizes is most suitable for making high-quality seams.

When connecting, the bath completely compresses the contact area. In this case, a gap of 2 mm must be left between the parts being connected to allow the metal to flow in and fill all the pores.

When carrying out welding work, in accordance with GOST and SNiP requirements, a reliable joint is obtained while maintaining characteristics along the entire length of the assembled structure.

Shifts of the workpieces are limited by a bath placed at the joint. Thread baths are used to connect critical joints, but this method requires cutting threads at the ends of the rods.

The part for installation is selected taking into account the small gap between the workpiece and the wall of the product. The electrode metal flows into it, forming an interatomic connection of the base metal with the electrode rod.

The sides at the edges of the bath do not allow metal to flow out, while the slag is squeezed out to the top of the seam. The vertical rods are connected in the same way when making columns.

Advantages and disadvantages

The welding material and molten reinforcement metal fill the bath without spreading and form a reliable seam that can withstand significant loads. The material of the part itself serves as additional reinforcement for the seam.

Other advantages of pool welding include:

• minimal costs due to rational use of surfacing material;
• the technology for performing all operations ensures high quality welds under similar conditions to other welding methods;
• This method has been repeatedly tested and verified; there is a lot of literature and manuals on how to carry out the work;
• For every rod size, there is a suitable tray - this is due to the wide range of products.

There are also disadvantages to the bath method. The use of steel baths can only be one-time use due to welding to the base metal. Copper baths, although they can be used several times, are quite expensive. It is also necessary to carry out preparatory work, which takes time.

The disadvantages are purely subjective, so the bathroom connection method is the most common.

Single-electrode method algorithm

To carry out work on fastening various products from A500C reinforcement, the best way is welding using copper plates. This weld pool is made without grooves to hold the metal, but the inside is made with a smooth surface, which makes it easy to dock the reinforcement.

The method is used when installing structures exposed to static and vibration loads. Welding machines can be used with direct and alternating current power; the main thing is that they must be of sufficient power and performance.

Bath welding begins from one of the sides, gradually moving towards the center. The electrode should advance slowly, making circular or crescent movements. This method will ensure uniform filling of the bath cavity and heating of the base metal.

When melting, the electrode is lowered, ensuring the formation of the shortest arc. The metal rises to the top edge of the bath, completely covering the fittings. After this, the welding bath is considered completed. When the seam has cooled, you can adjust the parts.

When stopping welding, be sure to knock off the slag and light an arc at the finished edge of the seam. This will make it possible to reliably cover the place where the seam stops and is interrupted. The seam should be completed in the middle of the bath to prevent holes and voids. Such places need to be cleaned of slag and boiled again.

Molds

To connect two strands of reinforcement, use a bracket-plate designed specifically for welding.

Copper baths or parts containing this metal are considered the most durable linings. The collapsible overlay is made from different grades of copper using casting, stamps and mechanical operations for processing blanks.

It is not recommended to use bronze or brass for making bathtubs. To ensure welding with small gaps, it is recommended to use a non-separable method for producing copper grooves. Such products can be used for welding more than 100 joints.

Multielectrode method

A distinctive feature of the multi-electrode welding method is the connection of several electrodes onto a special plate, a comb, which is inserted into a holder.

The holder handle is moved away from the body and the welding tire. For multi-electrode welding, AC machines are used.

This design works on the principle of single-electrode welding. The arc is lit on one side and moved to the second edge. It should be remembered that it is better to end the seam in the middle of the lining.

Having melted the end of the reinforcement, move on to the second end. The movements of the electrodes for filling the seam are also made in a circle or crescent, gradually lowering as the set of electrodes melts.

To strengthen the seam, it is recommended to periodically lower the electrodes into the weld pool. The method allows you to squeeze out the slag. Then the arc is ignited again and the electric welding process continues. It is recommended to carry out this operation more than 5 times.

If there is an inconvenient welding operation and the angle of inclination of the holder, do not create a gap between the rods and connect them close to each other.

When performing pool welding in a vertical position, the electrodes are carried out without a strong tilt, the plate does not deviate from the perpendicular position.

For this method, the use of non-separable steel baths is quite rare. They are used when it is impossible to install specialized overlays. The most commonly used are metal collapsible or stamped linings.

There are a few key points to pay attention to. In the case of competent, careful and high-quality welding work using the joining method of fittings, a strong, reliable weld is obtained.

It allows you to use metal structures and concrete components for a long time. This is due to the preservation of the flexibility and strength of the reinforcement at the assembly site. The main thing is that welding work is carried out by highly qualified specialists while observing welding technology.

Source: https://svaring.com/welding/vidy/vannaja-svarka-armatury