The selection of electrodes for pipe welding is a fundamental process, on which the quality of the weld and its reliability will depend as a result. Absolutely all the nuances, even the most insignificant, must be taken into account, but, unfortunately, many welders, including professionals, do not always pay due attention to this.

When it comes to laying shaped or standard pipes, sooner or later you will have to use a welding machine. When choosing an electrode, you should be aware of the first and most important difference between them, they can be melting and non-melting.

For the production of this type of electrodes, a welding wire is used, it has a protective coating, which is necessary to stabilize the operation and the required magnetic characteristics. And non-consumable is made of graphite, tungsten and electric coal.

A coating for a consumable electrode is also necessary to be able to obtain a high-quality and reliable seam; it is applied by immersion in molten metal and pressing.

What are the advantages of consumable electrodes:

1. They allow you to weld from any position.
2. Enhanced performance.
3. Minimal effect of oxidation on the bonding process.
4. Safe for the welder during work.

Disadvantages:

• high radiation of the welding arc;
• spatter during welding;
• current limits are set.

These are the main parameters that should be taken into account before choosing the required electrodes.

How to choose the right electrode

The service life of the materials directly depends on which electrode will be used for welding heating pipes or other structures.

Most often, specialists use thicker rods. This happens because they are able to give the welding process the necessary atmosphere, which prevents air from entering the joint zone. But it is also worth considering that they differ in a large amount of slag released. And they, in turn, can affect the reliability of docking. Therefore, it is necessary to learn how to find a middle ground for optimal work with pipeline welding.

How to choose an electrode, if we take into account the thickness of the pipe?

1. If the thickness of, for example, stainless pipes is 5 mm, then the electrode should have a diameter of not more than 3 mm.
2. When the pipe is larger than 5mm, 4mm rods will be required.
3. Also, a diameter of 4 mm is used for the multilayer formation of a welded joint.

It is also worth considering the maximum current that the rod is able to pass through itself, and the consumption of electrodes when welding pipes, which will help reduce cash investments.

Pipeline Welding Process

After the choice is made, you can proceed to the welding process. To begin with, it is worth understanding how to move the arc along the connection, a few simple tips from experts will help with this:

• the arc is carried out transversely, using oscillatory movements to obtain the required thickness of the seam;
• if you advance the arc longitudinally, this will make it possible to make a thin seam with a height that depends entirely on the speed of movement of the selected rod along the surface to be joined;
• to maintain the stability of the electric arc, it must be carried out gradually throughout the entire welding process.

Note!

If the pipe has a small diameter, it must be welded with an integral joint, and if it has a large thickness, the seam must be intermittent.

Safety regulations

Safety is that component of the welding process, which should be approached with great responsibility. After all, if you ignore the rules, you can get serious injuries, such as burns from molten metal, eye burns from an arc flash, or become a victim of electric shock. You can avoid such situations by following simple recommendations, namely:

• during work, the welder should not have wet clothes;
• be sure to use a protective face mask;
• all wires through which current flows must be insulated in any way possible;
• before starting welding, you must not forget about the grounding of the unit and additional devices, if any;
• in small rooms it is necessary to use rubber shoes or lay a rubber mat, it will play the role of an insulator.

Conclusion

To make the choice of an electrode more prepared, it is worth taking into account the consumption rate of the rods and taking into account the binding of a certain type of pipe to the material from which the rods are made. And for an even better understanding of the selection procedure, it is best to seek advice from experienced professionals who have extensive experience in carrying out this kind of work.

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

In our article, we will talk about which electrodes should be used for pipe welding in one case or another, as well as how it is better 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 this or that electrode has various parameters, which include, for example, the impact strength of the finished seams, the mechanical properties of the seams, as well as their ability to bend. What electrodes are most often used to weld pipes?

Acid coated electrodes. In the process of manufacturing 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.

Basic coated electrodes. In the process of their manufacture, fluorine 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 are resistant to cracking, and also acquire high viscosity.

Cellulosic coated electrodes. 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.

Rutile electrodes. For the manufacture of rutile concentrate is used. In the process of welding, seams with high viscosity are obtained, and slag is also easily removed after the work done.

Mixed coated electrodes. 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.

Among other things, welding electrodes can also be divided into two more categories:

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

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

How to weld pipes, select electrodes and make seams?

When connecting pipes, welding is most often used. Today on sale you can find a large selection of welding machines, both domestic and industrial, so many homeowners take up the welding work themselves.

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

Today, many different welding methods are used in construction.

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

• Thermal, which includes all methods of welding by melting.
• thermomechanical, which includes butt resistance welding, as well as a welding process using a magnetically controlled arc.
• Mechanical, which includes friction and explosion welding methods.

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

Preparatory work

Before proceeding with the implementation of welded joints, it is necessary to prepare the surfaces of the pipes and select the right materials for work.

Choice of electrodes

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

The whole variety of manufactured electrodes can be divided into two groups:

• consumable base electrodes;
• Non-consumable electrodes.

This classification is carried out by evaluating the material that is used to make the core of the electrodes. So, 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 evaluating their coverage.

Each type of coating is designed to solve specific problems, so it is extremely important to take this circumstance into account when choosing.

• Cellulosic coated electrodes (Grade C) are used for making circumferential and vertical seams on large diameter pipes.
• Rutile Acid Coated Electrodes (RA Grade) differ in the special structure of the slag formed during welding, which can be easily removed at the end of the work.
• Rutile coated electrodes (grades R, RR) are distinguished by easy re-ignition, a good degree of slag impact and allow you to create seams with a marketable external surface. They are used for setting tacks, as well as for creating fillet welds and welding the outer layers of the seams, which should have a beautiful appearance.
• Rutile cellulose coated electrodes (RC brand) are recommended for seams in any direction, including the most difficult case - when a vertical seam is formed from top to bottom.
• Basic coated electrodes (Grade B) allow you to create joints with excellent viscosity characteristics and the least chance of cracking.
  These electrodes are recommended for welding pipes with a large wall thickness, as well as in cases where it is necessary to maintain a high viscosity of the seam, 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, presence of a certificate, no deformation (ellipticity), no difference in the thickness of the pipes, compliance of the chemical composition of the pipe metal 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 blunting are measured.

The opening angle of the edges to create a good seam should be equal to 60-70 degrees. The amount of blunting, as a rule, is 2-2.5 mm.

• If the shape of the bevel of the edges of the pipes does not match, they are machined using chamfers, trimmers or grinders.
  To prepare large diameter pipes, milling machines are used or thermal preparation methods are used, for example, gas-acid or air-plasma cutting.

Welding

Consider how to cook pipes correctly.

Installation of tacks

• Tacks are an integral part of the weld, they are made using the same type of electrodes that will be used for the main welding.
• When performing welding, having a diameter of up to 300 mm, four tacks are performed, placing them evenly around the circumference. Each tack should be 3-4 mm high and 50 mm long.
• When welding pipes of larger diameter, tacks are placed every 250-300 mm.

When assembling pipelines, one should strive to ensure that the maximum number of joints is performed in a rotary position. Pipes having a wall thickness of up to 12 mm are connected by welding in three layers. Consider how to properly weld a pipe in a rotary position.

Rotary welding

The first welding layer is made 3-4 mm high, for this, electrodes with a diameter of 2 to 4 mm are used. The second layer is created using electrodes of a 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 that, the pipe is turned and the remaining two sectors are welded.
• Next, the pipe is turned again and the second layer of the seam is made on the first two sectors.
• The work is completed by performing the second layer of the seam in the third and fourth sectors, having previously turned the pipe over again.

The third layer of seam is applied in one direction as the pipe is rotated.

When welding pipes with a diameter of up to 200 mm, it is possible not to perform division into sectors, performing all layers of the seam in one direction when the pipe is rotated.

Plastic pipe welding

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

Therefore, the question of how to cook plastic pipes is of interest to many home craftsmen.

• For this, special welding machines are used.

When designing a pipeline from polypropylene pipes, it should be borne in mind that such pipes may stretch somewhat when heated.

• Heating nozzles are fixed in the device.

The required temperature is 250-270 degrees.

• Next, pipe sections of the size specified by the project are measured, and they are cut. The edges of the parts are recommended to be sharpened at a slight angle.
• A marker on the pipe marks the length of the connection with the fitting so that the end of the pipe does not abut against it.
• Pipe surfaces to be welded must be degreased.
• The fitting warms up a little longer than the pipe, so it is processed first. Then a 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 fixed in a smooth movement without turning. The seam should be fixed until it cools down.

Thus, it is possible to obtain reliable connections using plastic pipes - how to weld such parts is described above, however, when doing work, the following should be considered:

• To get a really reliable pipeline, you need to carefully consider the choice of raw materials, namely, purchase high-quality pipes and fittings.
• We must not forget about the need for mechanical processing of the joined edges, since otherwise it is impossible to obtain a high-quality connection. The end of the pipe after trimming must be cleaned using trimmers, shavers or files with a fine notch.

findings

The performance of pipe joints during the construction of pipelines is a responsible job, the quality of which determines the reliability of the networks under construction. Therefore, regardless of the material of the pipes used, welding must be carried out in strict accordance with the requirements of SNiP.

When building a country house, it is important to properly plan engineering communications. At the project stage, schemes for heating, water supply and sanitation are laid. Today, there are a large number of technological solutions to these issues. There are PVC plumbing and heating pipes and classic metal pipes on the market.

The choice of pipe type is influenced by a large number of factors. But, despite the increased popularity of polymer products, metal pipes remain popular and are often used to create engineering networks.

In order for the finished structure to be strong and durable, it is necessary to correctly connect all the joints. The main method of joining metal pipes is welding. And the quality of welding is affected not only by the skill of the master, but also by the correctly selected brand of electrode, suitable for connecting such products. With basic skills and the necessary equipment, welding of heating pipes can be done by hand.

Welding of heating pipes can be conditionally divided into several stages.

1. Preparation of equipment and tools.
2. Preparation of the welded surface.
3. Welding process.

To perform welding work, you will need a welding machine, a grinder, a hammer, a protective mask and gloves, as well as welding electrodes. The pipe surface to be welded must be clean up from rust, dirt and paint, as well as degrease. Cleaning must be done inside and outside to a depth of at least 1 cm. After that, you can start the welding process.

For beginners, rutile electrodes of the OK46, ANO-21, MP-3 and OZS-4 brands are recommended for welding heating and plumbing pipes. These electrodes are of the same type and have similar characteristics. Professionals can use UONI-13/45 brand electrodes. The choice of electrode diameter depends on the wall thickness of the pipe. With a metal thickness of up to 5 mm, electrodes with a diameter of 3 mm are suitable. For welding pipes with a wall thickness of up to 10 mm, electrodes with a diameter of 4 mm must be used. In this case, the surfacing is performed in several layers.

The strength of the welding current for each diameter and brand is set individually. Experienced welders are guided by their feelings. Beginners are advised to choose the welding modes indicated on the package with electrodes. The package also indicates the calcination modes. And if rutile-coated electrodes can be stored without calcination, then main brands necessarily subject to calcination. This is necessary to remove excess moisture from the coating, to ensure a high-quality and durable seam.

When performing welding work, remember to safety precautions. Use special protection and ground the welding machine. Do not use shoes with metal inserts.

After completion of work, it is necessary check tightness designs. Run water or gas through the pipes. There must be no leaks at the welding site. If everything is done correctly, then the pipe connection was successful.

You can choose welding electrodes and learn more about welding on the manufacturer's website: https://goodel.ru/

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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 plumbing pipes play far from the last violin in such works.

First of all, we should emphasize that such conductive rods can be both iron and 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 between consumables in order to see how best to choose them, and the video in this article will demonstrate visual information on our topic.

How they are distinguished

Electrodes made of metal can be consumable and non-consumable. 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 a wire (see photo above), while welding is carried out in a gas protective environment.

The non-melting type includes intriated, thoriated, lanthanized, and tungsten, so it is natural that their price is much higher.

In addition, the 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 Y, for alloyed and heat-resistant steels - with the letter T, but for the deposition of the surface layer - with the letter T.

As a rule, there is a coating on the rods, but it also differs 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 - with 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 - the 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 various positions, the electrodes are also classified into various types. So, they can be for the lower position vertical from the bottom up, horizontal and lower into the boat. In addition, the instruction also implies rods for any position.

By appointment. Types of materials

• Carbon and low alloy structural steels. In this case, the 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 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 acid coating. It consists of 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 with direct current of variable polarity.
• C - cellulose. It contains flour and other organic components, which are intended for the gas containment during welding.
• 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 spatter during the production of the seam.

Note. In domestic use (heating, frames), everything is simpler, since in most cases, for all cases, electrodes with a basic (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 weld a 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 welding (transformer or inverter), you will also select the consumable itself (for AC or DC).

Consumption rates

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

Consumption of electrodes when welding pipes per meter of seam

Consumption of electrodes when welding pipes for 1 joint

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

Conclusion

As you have seen, there are a fairly large number of electrode brands, but if you want to cook heating in 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 the 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 cracked coating (C) type, acidic (A) or basic (B), for carbon and low carbon steels.