Most professional and home welders face the need sooner or later. Not surprising! This is one of the most common types of welding. But pipe welding is characterized by increased requirements for the quality and tightness of the seams, especially for gas and water supply units. For these purposes, special electrodes are used.

Electrodes for welding pipelines are designed taking into account all the features of the future operation of pipes. are strong and durable, they withstand the maximum temperature load. Such electrodes have a special composition, due to which they provide good quality welded joints. Novice welders usually have a lot of questions on this topic. How to choose the right electrodes? What kind of rods to weld tubing pipe? What are the best electrodes for pipe welding? We will try to answer these and many other questions in this article.

How to cook a pipe if it is planned to introduce main gas supply through it? We recommend OK-46, LB-52 or UONI-13/55 brand electrodes (the same electrodes can be used to weld tubing pipe). All of the listed grades have a suitable composition, they can be made using manganese, phosphorus, sulfur or silicon. And OK-46 s electrodes are generally considered universal. In our experience, they are especially suitable for welding parts with a wide gap.

Also on the market there is a brand LB 52U with a basic coating. Let's dwell on it in more detail. Such electrodes contain a small amount of hydrogen, so the seam is very high quality. At the same time, it is stable, easily ignites, and completely boils the metal.

If it is necessary to weld especially critical assemblies (for example, rotary ones), while the pipe is made of carbon or low-alloy steel, then we recommend electrodes for welding pipes of the MTG-01K brand. The arc burns stably, the slag is removed easily and quickly, while the spatter of the metal is negligible.

Electrodes for heating pipes

If you need to weld heating pipes with high quality, then we recommend the following brands of electrodes: E42A, UONI 13/45 (diameter 3 mm). These rods have a thick coating, which makes it easy to weld carbon steel. Also, for welding heating pipes, grades E-09X1MF and TsL-20 are suitable. They are designed to form a strong seam when welding heat-resistant steel. These rods also have a fairly thick coating. If you need to weld stainless, carbon or alloy steel, then use TsL-9 with a basic coating. There is little hydrogen in such rods, and we already know that this guarantees excellent weld quality.

If you plan to weld pipes in which there will be a continuous supply of hot water and there may be increased pressure, then use electrodes for pipes of the MP-3 brand. The same rods can be used to weld tubing pipe. Electrodes of this brand have and are made of special wire. Manufacturers offer a diameter of 3 to 5 mm. When working with this grade, tilt the electrode towards the deposit and use a short arc. Then it will be as tight as possible.

It is very important to set the current correctly. The smaller the thickness of the metal and the diameter of the electrode, the lower the voltage value. If the voltage is set too low, the metal may not boil. And vice versa: if you set the current value too high, then the part may be deformed. Therefore, pay attention to the thickness of the metal and the dimensions of the electrode.

Plumbing electrodes

We recommend the following brands for welding water pipes: MN-5, MNZH5 (for), NZH-13 (for pipes from) and MNCH-2 (for pipe welding). If you have to do home welding with an inverter, and the pipes are made of ferrous metal, then you can use the brand MP-3s. They can qualitatively weld even a pipe with a diameter of 32 by 2.8 mm at low current.

If you need to do it, then use the MNC-2 electrodes. TsCh-4 is suitable for cold and hot welding, but note that it can only be used in the lower position. By the way, when choosing electrodes, pay attention to the presence of a coating. Be sure to buy coated rods, as it will protect the welding area from the negative effects of oxygen. We recommend electrodes for welding pipes with a thick coating.

If you have any specific type of work, then consult with the seller in the store. Read the information on the packages carefully. For most work, tube electrodes from manufacturers such as UONI, OZS, ANO, KOBELKO, ESAB are suitable. Among domestic manufacturers, we also recommend the electrodes of the Ural and Kamensky plants.

No matter where you live, in your house or in an apartment, you probably had to deal with the need to weld metal pipes for heating or plumbing.

When welding such pipes, you probably had to try hard, because these were responsible welds. In order for the welding to turn out to be of high quality, you probably used special electrodes for pipe welding.

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

This 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 ESAB electrodes with the same name "ESAB".

ESAB electrodes are one of the most popular electrodes , which are used when welding different types of steel, as well as when welding pipe structures. For pipeline welding best suited are ESAB's OK 53.70 and OK 74.70.

They are designed specifically for thorough penetration of the root of the seam, and if the root of the seam is perfectly welded, then 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 ESAB's OK electrodes, but have several disadvantages. For example, they have more metal spatter than OK 53.70 or OK 74.70 electrodes.

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

However, it is best to follow the advice of professional welders and use electrodes from ESAB. Of course, no one says 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 welding of the pipeline under pressure is only possible with these electrodes.

The quality of the resulting weld significantly depends on how correctly the electrodes for pipe welding are selected. Unfortunately, many welders underestimate the importance of their selection.

Welding electrodes are rods that supply current to the place where the seam should be made.

Varieties of electrodes used for pipe welding

Now there are quite a lot of varieties of electrodes, which differ in purpose, coating and production method.

The most important difference is that the electrode can be consumable or non-consumable.

This parameter depends on the material from which the electrode was made and the method of further processing. For the manufacture of non-consumable electrodes, tungsten, graphite and electrical coal are used. Consumable electrodes for welding pipelines are made from welding wire that is coated to protect, stabilize and impart the desired magnetic properties.

Coatings do not allow air to get on the electrode metal, which gives the welding arc combustion stability, and this, in turn, contributes to obtaining a better and more uniform weld. The coating on the electrode is applied by pressing or dipping into the molten material.

Advantages and disadvantages of consumable electrodes

Consumable electrodes have the following advantages:

Of course, these electrodes also have certain disadvantages, which include:

• Large radiation of the electric arc.
• Limitations on current parameters.
• Significant spatter of metal.

When working, these shortcomings should be taken into account. Electrode manufacturers are striving to improve their products to minimize the impact of these negative factors.

Deciphering the letter marking of the electrodes

According to GOST 9466-75, consumable electrodes have a number of letter designations indicating their parameters. The first shows the purpose - for which steel groups the electrode can be used.

Electrodes intended for welding low-alloy and carbon steels are indicated by the letter U, alloyed - L, high-alloyed - B. Also, the tensile strength of steel is important for choosing an electrode. It is indicated in kgf / mm².

The thickness of the electrode coating is also indicated by letters. The thin layer of the coating is marked M, the middle one is C, and even thicker ones are D and G.

The type of coverage is indicated as follows:

• A is sour.
• B is basic.
• C - cellulose.
• R - rutile.
• P - other.

The coating can be marked with two letters at once.

Features of welding joints of pipes and pipelines

A rather important parameter of the electrodes is the diameter. Electrodes for welding pipe joints are selected depending on the wall thickness of the pipe itself.

Accordingly, the thicker the pipe to be welded, the larger the required electrode diameter.

To make a good seam, the surface of the pipe to be welded must be thoroughly cleaned of rust, dirt or soil. The presence of dents or deformations of another kind can significantly complicate welding work or make it impossible at all.

Joint welding must be carried out continuously, without downtime or interruption. To make the seam strong, welding must be carried out in at least two layers. The next layer can only be applied when the previous one has been cleaned and fully prepared.

After analyzing all the material presented, we can come to the conclusion with which electrodes to weld pipes. Only with the right choice of them and compliance with all the requirements for the technical process, it is possible with a high probability to obtain a high-quality result from welding work.

The use of welding equipment to connect elements requires the possession of certain skills and abilities. To perform this procedure, it is important to take into account various nuances and parameters. Particular attention is paid to the choice of material for each individual case. It is the electrodes that affect 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, the characteristics of the material should be taken into account, since each type of electrode for pipe welding has individual characteristics. This means that each specific connection is made by certain electrodes. So, you need to study all the varieties to determine their relevance to a particular process.

Welding parameters of electrodes for pipes

The main advantage of rutile-acid electrodes for welding pipelines is the removal of slag with a narrow joint of elements.

• Rutile coating forms a seam with an attractive appearance, removes slags well, quickly ignites when reused. Application - creating corner joints and tacks.
• Rutile + basic coating makes it possible to obtain root joints. They are mainly used on pipelines, the elements of which have a medium and small diameter size.
• Rutile cellulose coated electrodes are considered to be a universal solution for welding thick coated elements.
• Cellulose coating makes it possible to perform circumferential seams when connecting pipes with a high diameter index. These are the best electrodes for pipe welding.
• The main electrodes are used for any docking, regardless of the position of the seam. They also perform welding of fixed pipe joints, which is very convenient. Although 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 the main electrodes when connecting strong steel.

Material properties

The weld metal must have the same toughness and strength as the base metal. Therefore, it is necessary to study the brand of electrodes for pipe welding, which must comply with DIN EN 499. 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 that promotes the development of a crack, -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 can contain. H5 means 5 ml/100 g.

Diametric section

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

The nominal diameter is the uncoated bar thickness. The coating thickness is different for each type of electrodes, it is regulated by GOST 9466-75.

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

• A thin coating is considered equal to or less than 1.2.
• Average coverage is defined as equal to or less than 1.45.
• With an equal ratio of diameters or less than 1.8 - a thick coating.
• If the diameter ratio is more than 1.8. That coating will be especially thick.

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

Estimated electrode power

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 strength 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 industrial equipment with high productivity.
• Electrodes with a diameter of 6 mm allow you to work with any kind of steel at a current strength of 230-370 A, the thickness of the welded material is from 4 to 15 mm. Used for professional purposes.
• For welding products made of alloyed and low-carbon steel, electrodes with a diameter of 1.5 to 3 mm are suitable. In this case, the materials to be joined can have a thickness in the range of 1-5 mm. Using a material with a diameter of 2-5 mm, it is possible to solve the problem of which electrodes are best for welding heating pipes.

It is worth noting that for each type of electrode, its own current strength is determined.

Before starting work, it is worth deciding which electrodes to weld the pipes with. Properly selected material for welding allows you to make a high-quality and durable seam.

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, availability 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.

conclusions

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.