Using welding equipment to connect elements requires certain skills and abilities. To perform this procedure, it is important to take into account various nuances and parameters. Special attention pay attention to the choice of material for each individual case. It is the electrodes that influence the welding mode, the size of the seam and its properties. However, they have the most important effect on the strength of the joint.

When making any connection, you should take into account the characteristics of the material, since each type of electrode for welding pipes has its own individual characteristics. This means that each specific connection is made by specific electrodes. This means that all varieties need to be studied to determine their suitability for a specific process.

Welding parameters of electrodes for pipes

The main advantage of rutile acid electrodes for welding pipelines is the removal of slag during narrow joints of elements.

• Rutile coating forms a seam with an attractive appearance, removes slag well, and ignites quickly when reused. Application - creation corner connections and potholders.
• Rutile + basic coating makes it possible to obtain root joints. Mainly used on pipelines whose elements have medium and small diameters.
• Electrodes with rutile-cellulose coating are considered universal solution for welding elements with thick coating.
• The cellulose coating makes it possible to perform circumferential seams when connecting pipes with a high diametrical index. These are the best electrodes for pipe welding.
• The main electrodes are used for any joining, regardless of the position of the seam. They also perform welding of non-rotating pipe joints, which is very convenient. Despite the fact that the seam from such welding has a less attractive appearance, the risk of cracks in the weld is reduced. The greatest effect from the use of such electrodes can be obtained when connecting elements with thick walls and poor welding properties. It is also effective to use basic electrodes when joining strong steel.

Material properties

The weld metal must have similar toughness and strength as the base metal. Therefore, it is necessary to study the brand of electrodes for pipe welding, which must comply with the DIN EN 499 standard. This document regulates the tensile strength, yield strength and toughness of the weld metal.

For example, electrodes with the designation E 46 3 B 4 2 H5 have the following parameters:

• The letter E denotes electrodes intended for manual welding. You can use such electrodes for welding water pipes.
• Next comes the yield strength indicator, 460 N/mm 2 is considered the minimum limit.
• The next designation is the temperature conducive to crack development, -30 0 C.
• B - means the type of coating, in this case - the main one.
• The next number is the applied current. 4 – welding using direct current.
• Next comes the designation of the direction of the seam. 2 – any, excluding vertical.
• The last designation is the amount of hydrogen that the deposited metal may contain. H5 means 5 ml/100 g.

Diametral section

The diameter of the electrodes for pipelines is of great importance. This value affects the consumption of filler material and the properties of the seams.

The nominal diameter is the thickness of the rod without coating. The coating thickness is different for each type of electrode and is regulated by GOST 9466-75.

The coating can be determined by the ratio of the total diameter of the electrode to the diameter of the rod:

• A coating is considered thin if the ratio is equal or less than 1.2.
• Average coverage is defined as equal to or less than 1.45.
• If the diameter ratio is equal or less than 1.8, the coating is thick.
• If the diameter ratio is more than 1.8. That coating will be especially thick.

It is worth noting that imported products must also meet these rules. However, it is rarely possible to note that their diameters comply with Russian standards.

Calculated power of electrodes

Depending on the diameter, the main capabilities of the electrodes are determined:

• When working with electrodes with a diameter of 8-12 mm, the current should not exceed 450 A, the thickness of the material being welded can be higher than 8 mm. The length of such electrodes is 35-45 cm. The main application is equipment industrial use with high performance.
• Electrodes with a diameter of 6 mm allow you to work with any type of steel at a current of 230-370 A, the thickness of the material being welded is from 4 to 15 mm. Used for professional purposes.
• For welding products made of alloy and low-carbon steel, electrodes with a diameter of 1.5 to 3 mm are suitable. In this case, the materials being joined can have a thickness in the range of 1-5 mm. Using a material with a diameter of 2-5 mm, you can solve the problem of which electrodes are best for welding heating pipes.

It is worth noting that each type of electrode has its own current strength.

Before starting work, you should decide which electrodes to weld pipes with. The correctly selected material for welding allows you to make a high-quality and durable seam.

There is an opinion that welding pipes is quite simple technological operation, which even a beginner can handle.

Indeed, it would seem that there is nothing complicated here. The parts are quite large, the connecting surfaces are well adjusted to each other and processed, the material is of high quality. At first glance, there is everything necessary to form an aesthetic and durable seam!

In practice, however, it turns out completely differently. This process is quite difficult, especially if we're talking about on the formation of a full-fledged pipeline operating under pressure. The best specialists are attracted to work with its segments.

Why is this happening? How to perform high-quality welding without significant experience? What tips and tricks should you follow?

The most common and popular technique is electric arc welding.

Yes, it has alternatives in the form of gas welding, but its undeniable advantages lie in simplicity, a minimal set of equipment and a result that meets the most stringent standards.

Even when designing main pipelines, this method is used. To achieve high quality, you must treat your work with full responsibility.

Selecting Electrodes

Connecting Segments steel pipelines must be carried out using high-quality consumables, otherwise it is unlikely that a good result will be achieved.

For example, when it comes to choosing electrodes, the following models are considered the best:

• , ANO-24 and. They operate on alternating currents. Work is allowed even with wet coating. The cost of the products is low, which explains their demand in everyday life; they are ideal for connecting structural elements of gates, greenhouses and other light-weight structures that do not experience high loads. Work with pipelines in which the medium is transported under significant pressure is not permitted.
• . The quality of the cores deserves flattering reviews even from professional welders, but they have a disadvantage - work cannot be carried out at high speed. It is necessary to constantly monitor the stability of the arc; the weld is deposited gradually, so the worker must have some experience in interacting with classic ANO and MR electrodes.
• Excellent for metal pipes. This is a Japanese development. It is the one that is preferred when implementing large projects. They form an even and stable arc, the resulting seam combines strength and aesthetics. The downside is the rather high cost, but they are suitable for both specialists and beginners.

Watch a video on the topic of which electrodes to use for welding pipes:

Basic methods

The connection can be made in one of the following ways:

1. Butt joint, when the pipes to be connected are placed opposite each other. The most common option, characterized by relative ease of implementation. However, it is also characterized by certain difficulties. The first point is that it is better to work from below. The second point is that the metal must be thoroughly welded so that the depth of welding corresponds to the thickness of the wall.
2. Overlapping. This method is focused on connecting elements that initially differ in diameter, or segments, one of which is flared, that is, its diameter is intentionally increased by mechanical action.
3. The T-joint is made at a 90-degree angle.
4. A corner connection assumes that the angle between the connected segments is less than 90 degrees.

Before electric welding pipes, it is worth remembering a number of tips, following which will simplify the process and also improve the quality of the final result:

• If the connection is made using the butt or tee method, then electrodes whose diameter varies from 2 to 3 millimeters perform best.
• The recommended amperage is from 80 to 100 amperes, with the exception of overlap welding, when it is recommended to increase it to 120 amperes.
• When filling a welding seam, you need to ensure that the rise of the metal above the plane of the element reaches 2-3 millimeters.
• If the cross-section of the pipe is not the usual ovals or circles, but profiles, that is, rectangles and squares, then a point method of connecting it is used.

Its essence is that initially you need to weld a small area on one of the sides. Next - a similar section on the opposite side, then - on the remaining two planes. Only after this the pipe is finally welded.

This approach makes it possible to eliminate the possibility of warping of the product when the temperature rises; its geometry remains stable.

Preparatory operations

The final quality of the joint depends not only on the professionalism of the welder and the use of the “correct” electrodes, but also on how well the preliminary preparation is done.

It consists of the following operations:

• Checking the compliance of the geometry of the connected elements with the selected technology. It must be remembered that the wall thickness must be identical, otherwise it will not be possible to fully weld a thick-walled pipe, and in the case of working with a thin-walled product, on the contrary, the risk of burn-through increases.
• The presence of defects on the welded products, be it cracks, creases or deformations, is not allowed. During the process of thermal expansion, they can turn into areas of complete destruction of the structure.
• Geometric deviations of the cut are not allowed. Its angle must be 90 degrees, otherwise the welding seam will not be strong enough and problems will arise with its formation, which will pose a threat of destruction of the entire structure.
• The edges of the connected pipes must be cleaned until a shiny metal surface appears, for which coarse sandpaper or a special brush is used. The minimum length of the area to be cleaned is a centimeter from the edge.
• Grease and other contaminants, traces of paint and corrosion are removed. Most effective remedy removal - chemical solvent.

This video shows how to prepare the edges of a pipe for clearance using a grinder:

Process Features

Pipe welding technology involves following following rules:

• The seam must be continuous, that is, end at the point of its beginning. Tearing of the electrode from the surface is not allowed. It is impossible to follow the rule if the pipe diameter is too large. In such a situation, multilayer welding is used. The number of layers must be correlated with the thickness of the walls.

2 layers correspond to a thickness of less than 6 millimeters, 3 - from 6 to 12, 4 - more than 12. Before applying subsequent layers, you need to make sure that the first one has cooled completely.

• Before welding two pipes, they need to be fixed. The tack will simplify the work, eliminate transverse and longitudinal movements, and allow you to form an even and strong seam without unnecessary effort.
• When the pipe wall thickness is more than 4 millimeters, it is possible to form a root seam, the main feature of which is to fill the area between adjacent edges to the full depth. An alternative to a root seam is a roller analogue, which is identified by a 3 mm bead on top of the seam.
• Checking the quality of the seam. It is tapped with a hammer, which allows you to remove slag inclusions. After this, a visual inspection is carried out; cracks, areas with insufficient penetration, chips, gouges, and burns are not allowed.

If a liquid or other medium under pressure will be transported through pipes, a test run is carried out to determine the tightness.

Useful video

Watch the video where an experienced welder shows how to easily and quickly weld pipes for beginners:

Video for beginner welders, welding pipes with a crescent:

Conclusion

So, welding pipes is a responsible task, but with the proper approach and careful attention, even beginners can cope with it. The main thing is to do everything according to the instructions, not to deviate from technology, to remember all the little things.

Regardless of where you live, in your house or in an apartment, you have probably had to deal with the need to weld metal pipes for heating or water supply.

When welding such pipes, you probably had to try a lot, because these were critical welds. In order for the welding to be of high quality, you probably used special electrodes for welding pipes.

With pipes that will subsequently be subjected to high blood pressure things are different, because with such welding, the seams must be as strong as possible, that is, capable of withstanding heavy loads. However, in order for the welding seam to be of high quality and durable, your skill alone is not enough.

It takes more than just experience. Yes, you need suitable electrodes, which, thanks to their special structure, will be able to make the welding seam you need. One of the most popular electrodes used in the construction of gas pipelines, oil pipelines and other critical systems , are electrodes from ESAB with the same name "ESAB".

ESAB electrodes are among the most popular electrodes which are used in welding different types steel, as well as when welding pipe structures. For welding pipelines ESAB electrodes OK 53.70 and OK 74.70.

They are designed specifically for thorough welding of the root of the seam, and if the root of the seam is welded perfectly, this means that further welding will be successful. They are also used as a filling material, and also for welding the facing layer, which will be visible to people. ESAB's wide range of electrodes allows you to select the best electrodes for welding critical pipelines.

In addition to this type of electrode, MP-3 electrodes are sometimes used for welding pipelines under pressure. They are similar in many ways to OK electrodes from ESAB, but have several disadvantages. For example, they have more metal spatter than electrodes OK 53.70 or OK 74.70.

If a novice welder decides to weld pipelines with ESAB or MP-3 electrodes, then he is on the right track, because high quality Both brands of electrodes will help him quickly learn how to weld, because with their help welding will happen quickly and comfortably.

However, it is best to follow the advice of professional welders and use electrodes from ESAB. Of course, no one is saying that MP-3 electrodes are bad, but nevertheless, many professionals choose ESAB. Most likely, almost all welders know that the experience of professionals is invaluable, so you need to listen to it.

No matter what, buy electrodes and use them for their intended purpose, just remember that high-quality pipeline welding under pressure is only possible with these electrodes.

Electrodes for welding heating and water supply pipes. Which electrodes are best for welding heating pipes

Electrodes for heating and water supply pipes

The strength of the weld depends not only on the professionalism of the welder performing the work, but also on the quality of the electrodes used, although their importance is not rated as highly as they deserve.

The role of the electrodes, with which welding work is carried out, for connecting heating and water supply pipes, is very important if you need to obtain a high-quality weld. Welding electrodes used for welding pipes are rods that conduct current to the welding site. Currently, the modern market provides a huge selection of welding electrodes with various types of coating, designed for welding work.

At the moment, electrodes are divided into two large groups, melting and non-melting, and many subgroups differing in the type of coating. Division into consumable and non-consumable electrodes according to the type of metal used for their manufacture. Non-consumable electrodes for welding pipes are produced from graphite, tungsten or electrical coal.

Non-consumable electrodes, in turn, are made from welding wire. Magnetic, protective and stabilizing coatings are applied to the finished rods. By means of marking, that is letter designations on the box, you just need to select an electrode suitable for a particular welding job. Before the beginning welding work Make sure the pipe surface is dry and clean. When welding pieces of pipe, be sure to straighten the edges and only then begin welding work. If the pipe is deformed in the form of dents, welding work is not carried out.

Thin-walled water pipes, as well as gas pipes, made of identical material, are welded with electrodes, avoiding downtime in the welding process, and a minimum of two layers are applied. To apply the next layer, the previous one is thoroughly cleaned and prepared for welding.

A high-quality pipe connection can be made if all technological rules and the correct electrodes are selected. One of the most good electrodes are OK-46, which burn well, easily fill large gaps and can be used to weld below and above.

elektrod-3g.ru

How to properly weld a heating pipe?

April 27, 2017

It is quite possible to insert into a heating pipe without using welding, but you will not be able to do it yourself without the use of special equipment. Therefore, to connect to the main heating system You will also need to use welding. In order to qualitatively weld metal elements of various kinds together, it is necessary to understand what exactly welding is.

The principle of this technology is as follows: metal blank under influence high strength current and a certain voltage begins to melt and joins with a similar edge of another workpiece. Products begin to penetrate each other, their particles intersect with each other at the molecular level. Largely due to this, electric welding of metal heating pipes is considered to be one of the most reliable technologies, which allows for very high level connection strength.

Types of electrodes

An electric welding electrode is a metal rod of a certain diameter, which has a special coating for welding work. The thickness of this consumable can be different - this indicator should be selected depending on the thickness of the metal you plan to connect. The electrode coating is intended for additional protection steel elements and weld pool from direct impact external environment. Moreover, it helps make the arc burn much better.



Before directly purchasing electrodes, it is advisable to consult with welders or neighbors who periodically carry out welding work at home, what kind of consumables they use. Welding metal heating pipes with counterfeit or low-quality electrodes will result in a low-quality joint that will begin to leak over time. It must be said that reliable electrodes cannot be cheap.

When making a home pipeline using electric welding, it is advisable to use electrodes with a diameter of 2 to 5 mm. Coverage also plays an important role. It comes in different types:

• the main thing is that it is universal, helps to obtain a high-quality connection even when using cold welding. During subsequent operation, the seams almost never crack and have excellent toughness properties;
• made on the basis of cellulose and rutile. Designed for forming complex joints, in particular a vertical seam running strictly from top to bottom;
• rutile coating will look most attractive. Slag can be easily removed from the joint surface, and the arc is very easy to ignite. Such electrodes are usually used in the process of creating tacks or for forming fillet welds;
• a coating based on rutile and acid allows you to obtain not only a high-quality seam, but also a slag with its own structure. Once the heating pipes are welded by electric welding, it will be very easy to remove;
• Cellulose coating is ideal for structures with large diameters. Thanks to this coating, you can quickly and reliably form not only a vertical, but also a circular seam.

Surface preparation

Before proceeding with the actual work, the surface of the elements to be joined should be thoroughly dried and cleaned with a brush in order to obtain a metallic shine, remove all traces of corrosion, and so on. If the pipe has a deformed section, it must be removed. Clean approximately two centimeters from each end of the workpiece.

If the pipe has a diameter of no more than 89 mm with a thickness of 2 to 5 mm, then it is best to use electrodes whose thickness is about 3 mm. Thinner electrodes will not melt the metal over its entire depth, and thick products are inconvenient during the work.

To understand how to weld correctly, it is necessary to take into account that there are several types of welded joints:

• butt;
• overlap;
• corner;
• T-bar;
• criss-cross.

Work technology

First of all, insert the electrode into the holder and ignite the arc by striking it across the base metal. This makes it possible to weld heating pipes using electric welding. If everything was done correctly, a corresponding electric arc will be created, due to which the metal will melt. The electrode must be kept at a distance of about 5 mm from the surface of the workpieces in the area where they are planned to be connected. The pipe should be welded using electric welding at a certain angle - about 70 degrees. The suture is placed carefully oscillatory movements, only in this case the product combination of elements will be of the highest quality.

You can move the electrode along a zigzag crescent-shaped path. A corresponding roller will form in the area where the arc is formed. When the connection is completed or the electrode runs out, you need to let the joint cool a little, and then knock off the slag from the joint surface. It is possible that several additional stitches will be needed. The main thing to remember is that after each pass you need to knock off the slag.

Cold welding for heating pipes can be used even at home by a novice welder. The welding process itself begins with the formation of tack welds, regardless of the type of connection. Tacks are made using the same electrodes that will later form the entire seam. If the diameter of the pipe is not too large, you can make only two or three tacks - they will hold the structure in one position, preventing the elements from moving relative to each other. This will make the work much easier in the future.

Selecting a welding machine

IN Lately Inverter welding machines are the most popular in both domestic and industrial settings. They are of excellent quality, allowing for constant arc burning and the formation of a reliable weld pool. As a result, by using this device you can get the most quality connection.

The inverter equipment is not too heavy, which makes it easy to move it from one place to another - for ease of transportation it is equipped with a special strap. If necessary, it can be used in autonomous mode - it can be connected to a gasoline or diesel generator.



Transformer welding machines are more bulky and not very reliable. They create quite a serious load on electrical network, which in the future may cause short circuit. Because of this, it is undesirable to connect them to various types of gasoline or diesel generators.

electrod.biz

Selecting electrodes for pipe welding



The strength of the weld directly depends on the correct choice of electrodes for welding pipes, although many people underestimate the importance of choosing them correctly.

Welding electrodes for pipes are rods through which current is supplied to the welding site. Nowadays, the range of such electrodes is very diverse. They differ in their purpose, the coatings used and the manufacturing method.

Welding electrodes come in two main types: consumable and non-consumable. This classification is determined by the metal from which the electrodes are made, as well as the subsequent processing technology.

Non-consumable electrodes are made of graphite, tungsten, and also electrical coal. Welding wire is used as a material for the manufacture of such electrodes. Various types of magnetic, stabilizing or protective coatings are applied to the resulting rod. A protective coating is necessary to resist the penetration of air masses onto the electrode layer. This contributes to a more stable burning of the welding arc and a more even weld at the exit.

If you carefully examine the packaging of the electrodes, you can see various letters and numbers on it. Depending on the material of the products on which welding work will be carried out, the following letters can be seen on the packages: T, L, V, U, N. Types of coatings are indicated by the letters C, B, R, P, A (coatings can be acidic, rutile , basic, cellulose, etc.). Mixed coating of electrodes is also used. In this case, the name of the electrodes contains two letter values.

During renovation or construction pipeline systems, electrodes are used mainly for welding horizontal joints, rotary and non-rotary. The diameter of the electrode is selected depending on the thickness of the pipe wall. For pipelines with thick walls, large electrode sizes are used.

The surface of the pipe is thoroughly cleaned of dirt and soil before welding. If there are dents or other deformations on the pipes, welding work is impossible.

Electrodes are used to weld joints continuously, without downtime during the welding process and in at least two layers. Each subsequent layer is superimposed on the previous one only after it full preparation and cleaning.

Having analyzed the above, we can conclude that only with the correct choice of welding electrodes and observing all the subtleties and rules of the process can you be sure of good quality welding work carried out.

elektrod-3g.ru

Recommendations for choosing electrodes for welding: electrode consumption

The welding process is a rather complex and multi-component procedure that requires certain knowledge and skills. To perform a high-quality connection using welding, many nuances and parameters should be taken into account. In particular, great importance has the correct choice of electrodes for a particular case. After all, the welding mode, the amount of deposited material, the composition of the weld metal, and therefore the characteristics of the resulting weld will depend on this. Therefore, the strength of the connection largely depends on this choice.



Therefore, it must be done taking into account the properties of the material and parameters. After all, each type of electrode has its own characteristics, and therefore is suitable for performing specific tasks. Therefore, it is worth considering each type of electrode that may be suitable for a particular application.

Selection by welding parameters

Rutile-acid type products have the advantage of removing slag in narrow joints.

• Rutile allows you to get an attractive appearance of the seam, the slag is easily removed, and re-ignition is easy. Used for tacks, upper layers and creating fillet welds.
• Electrodes with a rutile-base coating are used to obtain root welds, as well as in the construction of medium and small diameter pipelines.
• Rutile-cellulose has proven itself excellently in various positions. This is a universal option if the product has a thick coating.
• Cellulose ones are used for joining large diameter pipes with circumferential seams. They are suitable for making vertical seams from top to bottom. Therefore, such products are used for laying pipelines.

The main electrodes can be used for connection in any position. However appearance the seam turns out a little worse than in other cases. However, such products reduce the likelihood of cracks in the weld metal.



Effective for large wall thicknesses, as well as for poor weldability of the material. These electrodes are effectively used for welding strong steels.

Selection by material properties

In the weld metal, as in the main metal, almost the same toughness and strength indicators should be observed.

To ensure that the choice is correct according to DIN EN 499, there are instructions on the values ​​of tensile strength, yield strength, and toughness of the weld metal.

Let's give an example. Let's say the designation E 46 3 B 4 2 H5:

• E – electrode type – manual welding.
• 46 – yield strength 460 N/mm2, minimum.
• 3 – at a temperature of minus 30 degrees a crack develops, the work of which is 47 J.
• B – main electrode coating.
• 4 – DC welding.
• 2 – welding in all positions, with the exception of vertical from top to bottom.
• H5 – hydrogen content in the weld metal up to 5 ml/100 g.

The same designation systems exist for stainless, heat-resistant and high-strength electrodes.

Diameter

Important when choosing an electrode for welding pipes, it is necessary to determine its diameter. The characteristics of the seam, as well as the consumption of filler material, depend on this.

It should first be noted that the nominal diameter is the size of the rod, without coating. As for the thickness of the coating, it is individual, determined by GOST 9466-75 according to the formula: D/d. D is the coated diameter and d is the rod diameter. Ratio:

• Equal to or less than 1.2 - thin coating;
• Equal to or less than 1.45 - average coverage;
• Equal to or less than 1.80 – thick coating;
• More than 1.8 – especially thick coating.

It's interesting that foreign manufacturers adhere to similar rules, but the diameters of their products do not meet Russian standards.



Here are the main capabilities of electrodes, which differ in diameter:

• 8-12 mm - current up to 450 Amperes, and the metal being welded has a thickness of over 8 mm. Their length is 35-45 cm. For all types of steel, for high-performance industrial equipment.
• 6 mm - current strength is 230-370 Amperes, and the metal being welded has a thickness of 4-15 mm. Their length is 35-45 cm. For all types of steel, for professional equipment.
• 5 mm - current strength is 150-280 Amperes, and the metal being welded has a thickness of 4-15 mm. Their length is 35-45 cm. For all types of steel, for powerful equipment.
• 4 mm - current strength is 100-220 Amperes, and the metal being welded has a thickness of 2-10 mm. Their length is 35-45 cm. For all types of steel.
• 3 mm - current strength is 70-140 Amperes, and the metal being welded has a thickness of 2-5 mm. Their length is 30-45 cm. For alloy and low-carbon steel.
• 2.5 mm - current strength is 70-100 Amperes, and the metal being welded has a thickness of 1-3 mm. Their length is 25-35 cm. For alloy and low-carbon steel.
• 2 mm - current strength is 50-70 Amperes, and the metal being welded has a thickness of 1-2 mm. Their length is 25-30 cm. For alloy and low-carbon steel.
• 1.6 mm – current strength is 25-50 Amperes, and the metal being welded has a thickness of 1-2 mm. Their length is 20-25 cm. For alloy and low-carbon steel.
• 1 mm - current strength is 20-25 Amperes, and the metal being welded has a thickness of 1-1.5 mm.

It should be noted that each brand of electrodes may have its own current strength, so the specified parameters are approximate. The consumption will also differ.

Right choice the electrode is the key to a high-quality and durable seam, and therefore the entire structure. Therefore, this choice should be approached especially carefully.

trubygid.ru

What electrodes should be used to weld pipes? - Welder's Handbook

As before, welding is currently used to connect metal pipes. With its help, you can weld pipes quickly, reliably and efficiently. various diameters. Thanks to the abundance welding machines, today each of us can face this task at home.

In our article we will talk about what electrodes should be used for welding pipes in a given case, as well as the best way to weld pipes.

How are welding electrodes classified?

More than half of the welding electrodes found are designed to work with carbon and low-alloy steels. The type of a particular electrode has various parameters, which include, for example, the impact strength of finished seams, the mechanical properties of seams, as well as their ability to bend. What electrodes are most often used to weld pipes?



Acid coated electrodes. In the manufacturing process of such electrodes, metal oxides are used, and the electrodes themselves are used for welding under direct and alternating current. It is better not to use such electrodes for steels with a high content of carbon and sulfur.

Electrodes with basic coating. In the process of their manufacture, fluoride compounds and carbonates are used. It is advisable to use electrodes of this type for welding pipes with thick walls. In this case, the seams become resistant to cracking and also acquire high toughness.



Electrodes with cellulose coating. Accordingly, cellulose is used in the manufacturing process, which allows welding from top to bottom, while overheating of the electrodes is unacceptable. The disadvantage of such electrodes is the high probability of metal splashing during operation.

Electrodes with rutile coating. Rutile concentrate is used for production. During the welding process, seams with high viscosity are obtained, and slag is also easily removed after the work has been done.

Electrodes with mixed coating. With the help of such electrodes, it is quite convenient to weld pipes and obtain the necessary seams, depending on the composition of the incoming components.



Besides everything else, welding electrodes can also be divided into two more categories:

1. With a meltable core, which is made from a special welded wire, differing in diameter and properties.
2. With a non-consumable core, in the manufacture of which coal, graphite or tungsten material is used as the core itself.

Thus, these types of welding electrodes are usually used for welding pipes. Which electrode to choose depends on the specific situation. In this case, it is best to take a reference book and find the appropriate electrode to use for welding a particular pipe.

www.vse-o-svarke.org

What electrodes should be used to weld Pipes?

Of course, in modern industry the mechanized fusion welding method is widely used, but despite this, the most a large number of welding work metal structures, is still performed using manual arc welding. To perform manual arc welding, welding electrodes are used. A welding electrode is a metal or non-metallic rod whose task is to supply current to the welding site.

In turn, they are divided into melting and non-melting; these characteristics depend on the material used in the manufacture of welding electrodes. Thus, samples that cannot be melted are made from synthetic graphite, tungsten and electrical coal.

Melting electrodes are made from alloy, carbon or high-alloy wire. Under pressure, using the pressing method, a special protective coating is applied to the metal rod. This in turn ensures stable and consistent arc pressure. Consumable electrodes are used in welding own metal for fastening the weld seam.

Non-consumable electrodes only perform the function of alternating current conductors to the place of welding work, and in this case, the fastening of the weld occurs due to the melting of the filler rod or wire and the metal being fastened. They are called electrode rods and electrodes specially designed for contact welding.

Carbon electrodes are used if you need to make a neat and aesthetically beautiful welding seam; they are also good if you need to perform air-arc cutting of thick metal. Using electrodes at the welding seam site, you can significantly change it chemical composition and doping it. The introduction of filler material during welding makes it possible to perform melting. The electrodes have their own unique markings and are divided by diameter and length.

The selection of electrodes involved in welding work is carried out taking into account the coating, and are characterized by different levels technological and welding properties. There are several main types of coating: rutile, acidic, basic, cellulose, mixed and ilmenite. For each of the listed coatings, welding electrodes suitable for their properties are selected.

elektrod-3g.ru

How to weld pipes correctly, what electrodes to solder plastic communications with

When connecting pipes, welding is most often used. You can find it on sale today big choice welding machines, both domestic and industrial, so many homeowners undertake welding work themselves.

At the same time, beginners naturally have questions: how to weld pipes correctly, how to select electrodes, how to prepare surfaces for welding and check the quality of seams. Let's try to understand these problems.

Today in construction there are many various methods welding

Thus, according to the method of joining metal, welding is divided into:

• Thermal, which includes all welding methods by fusion.
• Thermomechanical, which includes butt contact welding, as well as a welding process using a magnetically controlled arc.
• Mechanical, which includes friction and explosion welding methods.

At enterprises and during the construction of pipe lines, in most cases, automatic and semi-automatic welding methods are used. In private construction, the manual arc welding method is widely used.

Preparatory work

Before you begin making welded joints, you need to prepare the surfaces of the pipes and select the right materials for the job.

Selecting Electrodes

To perform manual arc welding, electrodes are used as consumables. This material is available in a huge variety, so the question of which electrodes to use to weld pipes is extremely important.

The entire variety of electrodes produced can be divided into two groups:

• Electrodes with a consumable base;
• Non-consumable electrodes.

This classification is made by evaluating the material that is used to make the electrode core. Thus, consumable electrodes are made from welding wire of various thicknesses and compositions. The core of non-consumable electrodes is made of tungsten, graphite or electrical coal.

In addition, the classification of electrodes is carried out by assessing their coating.

Each type of coating is designed to solve certain tasks, therefore it is extremely important to take this circumstance into account when choosing.

• Cellulose-coated electrodes (grade C) are used to make circumferential and vertical welds on pipes large diameter.
• Electrodes coated with rutile acid type (RA grade) are distinguished by the special structure of the slag formed during welding, which can be easily removed at the end of the work.
• Electrodes with rutile coating (grades R, RR) are distinguished by easy re-ignition, a good degree of slag impact and allow you to create welds with commercial grade outer surface. They are used for setting tacks, as well as for creating corner seams and welding the outer layers of seams, which should have a beautiful appearance.
• Electrodes with rutile-cellulose coating (RC brand) are recommended for making seams in any direction, including the most difficult case - when forming a vertical seam from top to bottom.
• Basic coated electrodes (Grade B) produce welds with excellent toughness characteristics and the least likelihood of cracking. These electrodes are recommended for welding pipes with large thickness walls, as well as in cases where it is necessary to maintain high viscosity of the weld, for example, to create pipelines that will be operated at low temperatures.

Pipe surface preparation

Before welding pipes, it is necessary to prepare their edges, that is, the surfaces that will be involved in the welding process.

• Pipes should be checked for compliance with the requirements laid down in the pipeline design. Basic conditions: conformity of dimensions, availability of a certificate, absence of deformation (ellipseness), no difference in the thickness of the pipes, compliance of the chemical composition of the metal of the pipes and their mechanical properties with the requirements of GOST.
• When preparing the joints, they are cleaned of dirt, oil and traces of rust, the perpendicularity of the plane of the end of the pipe axis is checked, the angle of opening of the edge and the amount of bluntness are measured.

Edge opening angle to create good seam should be equal to 60-70 degrees. The amount of dullness is usually 2-2.5 mm.

• If the shape of the bevel of the edges of the pipes does not match, they are mechanically processed using chamferers, end-cutters or grinding machines. To prepare large-diameter pipes, milling machines are used or thermal methods preparation, for example, gas-acid or air-plasma cutting.

Performing welding

Let's look at how to properly weld pipes.

Installation of potholders

• Potholders are integral part weld, they are performed using the same type of electrodes that will be used for the main welding.
• When welding metal pipes (for heating, for example), having a diameter of up to 300 mm, four tack welds are made, placing them evenly around the circumference. Each tack should have a height of 3-4 mm and a length of 50 mm.
• When welding pipes of larger diameter, tacks are placed every 250-300 mm.

When assembling pipelines, you should strive to ensure that the maximum number of joints is made in a rotating position. Pipes with a wall thickness of up to 12 mm are connected by welding in three layers. Let's look at how to properly weld a pipe in a rotating position.

Rotary welding

The first welding layer is made with a height of 3-4 mm; for this, electrodes with a diameter of 2 to 4 mm are used. The second layer is created using electrodes of larger diameter.

They do the job like this:

• The joint is divided into four sectors.
• First, the first and second sectors located in the upper hemisphere of the pipe are welded.
• After which the pipe is turned and the remaining two sectors are welded.
• Next, the pipe is turned again and a second layer of seam is made on the first two sectors.
• The work is completed by making a second layer of seam in the third and fourth sectors, after first turning the pipe over again.

The third layer of seam is applied in one direction while rotating the pipe.

When welding pipes with a diameter of up to 200 mm, you can avoid dividing into sectors, performing all layers of the seam in one direction while rotating the pipe.

Welding plastic pipes

In private construction metal pipes Today they are rarely used, preferring to work with plastic.

So the question is how to cook plastic pipes, interests many home craftsmen.

When designing a pipeline from polypropylene pipes, it should be taken into account that when heated, such pipes may stretch somewhat.

• Heating nozzles are fixed in the device.

To weld polypropylene pipes, a temperature of 250-270 degrees is required.

• Next, pipe sections of the size specified by the project are measured and cut. It is recommended to sharpen the edges of the parts under small angle.
• A marker on the pipe marks the length of the connection with the fitting so that the end of the pipe does not rest against it.
• The surfaces of pipes that will be welded should be degreased.
• The fitting takes a little longer to heat up than the pipe, so it is treated first. Then the pipe is put on the heated nozzle. After warming up (the time depends on the characteristics of the device used), the parts are removed from the nozzle and secured with a smooth movement without turning. The seam should be fixed until it cools down.

Thus, you can obtain reliable connections using plastic pipes - how to weld such parts is described above, however, when performing the work, the following should be taken into account:

• To get a truly reliable pipeline, you need to carefully consider the choice of raw materials, namely, purchase high-quality pipes and connecting parts.
• We must not forget about the need machining joined edges, since otherwise it is impossible to obtain a high-quality connection. After cutting, the end of the pipe must be cleaned using trimmers, shaver or finely cut files.

conclusions

Making pipe joints during pipeline construction is a responsible job, the quality of which determines the reliability of the networks being constructed. Therefore, regardless of the material of the pipes used, welding work must be carried out in strict accordance with the requirements of SNiP.

o-trubah.ru

There is an erroneous conclusion that the level of quality of the weld depends only on the performer, but this is far from the case, and any good welder understands this - electrodes for welding heating and water pipes play a significant role in such work.

First of all, we want to emphasize that such conductive rods can be either iron or non-iron, in other words, carbon or graphite, but in this case, the second type does not interest us.

Let's look at what indicators it is possible to distinguish consumables in order to see how best to choose them, and the video in this article will demonstrate visual information on our topic.

How are they distinguished?

Electrodes made of metal can be melting or non-melting. The first type is possibly coated, with a steel, cast iron, copper, bronze or aluminum rod, but uncoated ones are currently used only in the form of wire (see photo above), while welding work is carried out in a gas protective environment.

The non-melting type includes intruded, thoriated, lanthanum, and tungsten, based on this, it is completely natural that their price is much higher.

In addition, electrodes are classified according to their purpose, in other words, according to the type of material to be processed. For high-carbon steel according to GOST 9467-75, the material is marked with the letter U, for alloy and heat-resistant steels - with the letter T, but for deposition of the surface layer - with the letter T.

As a rule, there is a coating on the rods, but it also varies and has its own marking in accordance with GOST 9466-75.

So, for example:

• narrow coverage is marked with the letter A (international format - A);
• middle - letter C (international format - B);
• thick - letter D (international format - R);
• and very thick - the letter G (international format - C).

In addition to the thickness of the coating layer, it is classified according to its type:

• A - sour;
• B - main thing;
• C - cellulose;
• R - rutile;
• P - mixed.

In addition, a mixed layer is possible:

• AR - acid-rutile;
• RB - rutile-basic;
• RP - rutile-cellulose;
• RJ - rutile, with an admixture of metal powder.

Note. Due to the fact that welding work can be carried out in different positions, electrodes here are classified into different types. So, they can be for the lower position, vertical from bottom to top, horizontal and bottom in a boat. In addition, the instructions also include rods for any position.

By appointment. Types of materials

• Carbon and low alloy structural steels. In this case, the temporary tensile strength can be up to 60 kgf/mm or 600 MPa.
• High alloy steel types, which are endowed with special properties.
• Structural steels where arc welding is used. Here the temporary tensile strength will already be more than 60 kgf/mm or 600 MPa.
• Surfacing of the surface layer of metal, which has special properties.
• Cast iron.
• Non-ferrous metals. (See also the article Sewerage in a cottage: highlights.)

More about coverage

• A - acid or sour coating. It contains oxides of iron, manganese and silicon.
• B is the main thing. It contains calcium fluoride and calcium carbonate. Welding work using such electrodes is carried out DC variable polarity.
• C - cellulose. It contains flour and other organic components, which are intended for a gas protective shell during welding operations.
• R - rutile. It contains rutile as the main component, and other mineral and organic components. In addition to gas protection, such components can significantly reduce spattering during weld production.

Note. IN household use(heating, frames) everything is simpler, since in most cases, for all cases, electrodes with a main (B) coating are used, the diameter of which depends on the thickness of the metal. For example, if you are interested in which electrodes to cook with profile pipe, then given the narrow profile wall (1.0-1.5 mm), it is better for you to use a rod with a cross-section of 2 mm. Depending on the type of welding (transformer or inverter), you will begin to select the consumables itself (for alternating or direct current).

Consumption rates

For heating installation, the consumption rates of electrodes when welding pipes can be different, depending on the joining of the welded heating pipes and type of seam, but we will only consider vertical connection without beveled edges, as is most often used.

Consumption of electrodes when welding pipes per meter of seam

Pipe dimensions in mm	Deposition weight in kg	Electrodes by groups in kg
II	III	IV	V	VI
23?3	0,008	0,014	0,015	0,016	0,017	0,015
32?3	0,011	0,019	0,020	0,021	0,023	0,024
38?3	0,012	0,022	0,024	0,025	0,027	0,028
45?3	0,015	0,027	0,029	0,030	0,032	0,034
57?3	0,919	0,034	0,036	0,039	0,041	0,043

Consumption of electrodes when welding pipes per joint

Note. By and large, electrodes of any type are classified as one of the groups of welding materials. In addition to these, this includes filler rods, wire, shielding gases and filler fluxes.

Conclusion

As you have seen, there are quite a large number of brands of electrodes, but if you want to heat the house with your own hands, then you immediately need to discard the materials for high-alloy and non-ferrous steels, and cast iron.

In addition, the thickness of the walls of heating pipes, in most cases, is not less than 2 mm, then a 3 mm rod is needed. In addition, an electrode for all positions is suitable for you, with a medium-hard coating (C) type, acidic (A) or basic (B), for carbon and low-carbon steels.