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

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 its own 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 С.
• 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.

In autonomous heating systems, where a boiler with a high-temperature coolant is used, electric welding is most often used to connect pipes. This method of connecting pipe joints is tight and reliable, which is especially important under strong thermal loads.

Electric welding is a method of joining metal fragments (profiles, pipes) by the method of local metal melting. It is heated to the right temperature using an electric arc using a welding machine that converts alternating current to direct current.

An electric arc is formed on an electrode - a metal rod. A special environment is created in the area of ​​the arc, which simultaneously melts the metal, but does not allow it to come into contact with air and oxidize.

With the help of welding, it is possible to create a tight connection between two pipes, in which the likelihood of leakage, as with flange or box joints. To do this, it is important to perform a high-quality weld by fusing the metal at the edges of both pipe sections. Welders use several basic types of seams, depending on the type of metal, the thickness of the elements to be welded and their relative position:

• butt - the most common method of welding pipes, in which they are located opposite each other, connected by sections;
• in Taurus - two fragments of the pipe are arranged perpendicularly in the shape of the letter T;
• angular - parts are located relative to each other at an angle of 45 or 90 degrees;
• overlap - one section of the pipe is flared and put on top of the other, then welded.

Important! Steel pipes for heating and water supply systems are welded end-to-end or corner joint. This gives the most reliable and durable seam.

In addition to the connection method, there are also several types of weld that are used in certain cases:

• horizontal seam - performed with a mutual vertical arrangement of pipes (most often used in the installation of water supply and heating systems);
• vertical - the connection is made with a mutual horizontal arrangement of pipes, in which the master makes vertical movements with the electrode (from bottom to top, from top to bottom, etc.);
• ceiling - during welding, the electrode is under the workpiece to be welded, the welder has to hold his hand above his head;
• lower - in contrast to the ceiling, the electrode is on top of the parts to be joined.

For manual electric arc welding of joints of pipelines and pipes of boilers made of carbon, low-alloy and high-alloy steels, it is necessary to use electrodes that meet the requirements of GOST 9466-75, 9467-75 and 10052-75. The brand of electrodes for welding pipe joints should be selected depending on the brand of steel being welded (Table 10.24).

Electrodes for welding fasteners made of high-alloy steels to superheater pipes and other elements of the boiler or pipeline made of low-alloy pearlitic steels, as well as for welding fastening parts to each other, must be selected according to Table. 10.25. For welding fasteners (made of steel of any grade) to pipes made of austenitic steel, austenitic electrodes OZL-6, TsL-25, ZIO-8 and others of the type E-10Kh25N13G2 or electrodes EA-400 / 10u and EA-400 / 10t should be used. Fasteners must be welded to pipes made of steel EI 756 (regardless of the steel grade of fasteners) with ZIO-8, EA-400/10u or EA-400/10t electrodes.

The technological properties of the electrodes of each batch must be checked before their use, regardless of the availability of a certificate. This test must be performed by a certified welder. Alloyed electrodes intended for welding pipe systems of boilers and pipelines made of alloyed steels must be checked for compliance with the grade composition by steeloscopy of the deposited metal. The electrodes TsT-15 and TsT-26 are also checked for the content of ferrite in the deposited metal. This check should precede all other electrode tests.

Before welding production joints and testing, electrodes must be calcined (dried) under the following conditions:

• electrodes with a basic coating for welding pearlitic (carbon and low-alloy) steels (UONI-13/55, TsU-5, TMU-21, TML, TsL-39, TsL-20, etc.) - at 380–420 ° C for 1 hour; if after that the electrode coating noticeably loses its strength (the coating crumbles), the temperature should be reduced to 350 ° C and the exposure time to 0.5 h;
• basic coated electrodes for welding austenitic steels - at 200–250 °C for 1 hour;
• electrodes with a rutile coating, as well as a mixed coating, for example, rutile-basic or ilmenite (MP-3, OZS-6, OZS-4, etc.) - at 150–200 ° C for 1 hour;
• Cellulose-coated electrodes (VCC-4) – at 100–110 °C for 1 hour.

basic coated electrodes designed for welding pearlitic steels should be used within 3 days after calcination, other electrodes - within 15 days. After the specified period, the electrodes must be calcined before use.

The technological properties of electrodes intended for field welding of pipelines and pipes of boilers made of carbon and low-alloy steels (except for pipes of boiler heating surfaces) must be determined in the process of melting electrodes when welding in the overhead position of a one-sided tee joint of two shoulder straps in one layer 150 mm long, cut from pipes, or two plates measuring 180 × 140 mm (Fig. 10.2).

Fig.10.2. Welding of tee joints of plates (pipe lengths) to determine the technological properties of electrodes

The technological properties of the electrodes can also be checked when welding the ceiling section of pipes of the corresponding diameters or when welding a vertical joint of pipes with a diameter of 133–159 mm and a thickness of 10–18 mm from the corresponding steel. Welding must be carried out with preliminary and concomitant heating, if it is provided for a given steel grade. After welding the tee joint, the weld and the fracture are inspected. After welding the pipe joint, the seam is machined on a lathe with a layer up to 0.5 mm thick removed or translucent with gamma or X-rays to determine the continuity of the deposited metal. To facilitate the destruction of the sample, it is allowed to make an incision in the middle of the weld from the reinforcement side with a depth of not more than 20% of the thickness of the plates being welded.

Note.

Technological properties of electrodes intended for welding pipelines in the factory in the lower or vertical position can be determined when welding in a vertical position.

* Electrodes ANO-6M, MR-3, OZS-4, OZS-6, ANO-12, ANO-14 are designed for welding on both alternating and direct current of reverse polarity (+ on the electrode), VCC-4 electrodes on direct current of any polarity, other brands of electrodes - on direct current of reverse polarity.

** Can be used for welding the following products made of carbon steels: steam and hot water pipelines of categories 3 and 4; pipelines within the boiler and turbine with a working pressure of not more than 3.9 MPa (39 kgf / cm 2) and a temperature of not more than 350 ° C; pipes of heating surfaces of boilers with a working pressure of up to 5 MPa (50 kgf / cm 2); pipelines that are not subject to the rules of Gosgortekhnadzor, except for turbine control pipelines, oil pipelines and fuel oil pipelines.

*** For welding only the root layer of the joints of gas pipelines with a diameter of 219 mm or more without backing rings.

Notes:

1. If the project provides for pipes made of carbon steel, and pipes made of low-alloy steel of the same dimensions (diameter and wall thickness) are installed, then it is allowed to use carbon electrodes with a basic (calcium fluoride) coating.

1 For DC welding with reverse polarity.

Welding wire

For manual and automatic argon-arc welding with a non-consumable electrode, gas (acetylene-oxygen) welding, semi-automatic in carbon dioxide and automatic submerged arc welding, it is necessary to use a welding wire that meets the requirements of GOST 2246-70. The brand of welding wire should be selected according to the table. 10.26. For manual and automatic argon-arc welding of joints of superheating pipes made of steels 12Kh2MFB and 12Kh2MFSR, wire of grades Sv-08MH, Sv-08KhM, Sv-08KhMFA or Sv-08KhGSMFA should be used; from steels 12Kh18N10T, 08Kh18N10T, 12Kh18N12T and 08Kh18N12T - Sv-04Kh19N11MZ or Sv-04Kh19N9.

Each batch of wire must have a certificate indicating the manufacturer, its brand, diameter, heat number and chemical composition. Each skein (bay) of wire must be affixed with a tag indicating the manufacturer, its melting number, grade and diameter of the wire in accordance with GOST 2246-70.

In the absence of a certificate or tag, as well as in case of doubts about the quality of the wire, it is necessary to check its chemical composition. If the results of the chemical analysis are unsatisfactory, a second analysis is carried out on a double number of samples. If the reanalysis results are unsatisfactory, the wire is rejected.

The surface of the wire must be clean, free of scale, rust, oil and dirt. If necessary, it is cleaned of rust and dirt by sandblasting or etching in a 5% solution of hydrochloric or inhibited acid (3% solution of urotropine in hydrochloric acid). It is possible to clean the wire by passing it through special mechanical devices (including devices filled with welding flux, bricks, fragments of emery wheels and felt filters). Before cleaning, it is recommended to anneal the coil of wire at 150–200 °C for 1.5–2 hours. It is also allowed to clean the wire with emery cloth or in another way to a metallic sheen. When cleaning wire intended for automatic welding, sharp bends (fractures) should not be allowed. In all cases, after cleaning, the wire must first be washed in a 12-15% aqueous solution of soda ash at 70-90 ° C, then in hot water and dried in air.

Each bay (coil, coil) of alloyed wire before welding (regardless of the welding method) must be checked by steeloscopy to determine the main alloying elements. The ends of each coil (coil, coil) are subjected to steeloscopy. With unsatisfactory steeloscopy results, this bay cannot be used for welding until the exact chemical composition of the wire is established by quantitative chemical analysis.

Flat consumable rings, used as an additive for the root layer in automatic argon-arc welding with a non-consumable electrode of pipeline joints without remaining backing rings, are made from wire with a diameter of 3 or 4 mm. The wire grade is chosen depending on the steel grade of the pipes being welded according to Table. 10.26. The section of the melting ring is shown in fig. 10.3.

Rice. 10.3 Cross-section of a consumable flat ring Table 10.26. Applications for welding wire

* For manual and automatic argon-arc welding of the root layer of pipelines with a thickness of more than 10 mm from chromium-molybdenum and chromium-molybdenum-vanadium steels, wire Sv-08G2S or Sv-08GS should be used.

Flux for automatic welding

Flux AN-348A or OSC-45 should be used for automatic submerged arc welding of rotary joints of pipes made of carbon and low-alloy structural steel.

The flux must be stored in a dry room at a relative humidity of no more than 50% and a temperature of at least 15 °C.

Before use, the flux must be calcined at 300–400 °C for 5 hours, after which it can be used for 15 days. After the specified period, the flux should be ignited again before use.

Argon, oxygen, acetylene and carbon dioxide

As a shielding gas for manual and automatic argon-arc welding with a non-consumable electrode, argon of the highest, first and second grades with physical and chemical parameters in accordance with GOST 10157-79 is used (Table 10.27). It is equally allowed to use both gaseous and liquid argon.

1 Corresponds to the performance of gaseous argon obtained from the complete evaporation of a sample of liquid argon.

For gas acetylene-oxygen welding, it is necessary to use gaseous oxygen that meets the requirements of GOST 5583-78 for the highest or first grade (with a volume content of oxygen of at least 99.2%). Dissolved technical acetylene according to GOST 5457-75, supplied to the consumer in cylinders or produced on site from calcium carbide, meeting the requirements of GOST 1460-81, should be used as a combustible gas.

For semi-automatic welding in carbon dioxide, welding carbon dioxide of the first and second grade or food grade according to GOST 8050-85 is used as a shielding gas. The use of technical carbon dioxide is not permitted.

Before using gas from each cylinder, the quality of the gas should be checked, for which purpose a bead 100–150 mm long is welded onto the plate or pipe and the reliability of gas protection is determined by the appearance of the weld surface. If there are pores in the weld metal, the gas in this cylinder is rejected.

Tungsten electrodes for argon arc welding

For manual and automatic welding in an argon environment, rods of lanthanated tungsten or yttrated tungsten grade SVI-1 with a diameter of D= 2÷4 mm (Fig. 10.4).

Rice. 10.4. Form of sharpening of a tungsten electrode

To easily initiate the arc and increase the stability of its burning, the end of the tungsten electrode is sharpened into a cone (Fig. 10.4). In this case, the length of the conical part l should be 6–10 mm, and the diameter of the blunt

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 its own 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. 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, 460 N / mm2 is considered the minimum limit.
• The next designation is the temperature that promotes the development of a crack, -300C.
• 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.

tubespec.com

Electrodes for welding joints of pipes and pipelines

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:

• Ability to work from almost any position.
• Oxidation has little effect on the process.
• Better performance.
• Good worker protection during welding.

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 designated 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 to get a high-quality result from welding work with a high probability.

steelguide.ru

Choosing electrodes for pipe welding

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. It is necessary to take into account absolutely all the nuances, even the most insignificant ones, 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, it is worth knowing about the first and most important difference between them, they can be melting and non-melting.

Features of consumable electrodes

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.

Flaws:

• 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 starting the selection of the required electrodes.

How to choose the right electrode

The rods can differ in their thickness and the amount of coating. For welding galvanized pipes or any other, electrodes with a diameter of 2-5 mm are used. And the coating itself will be from 5% to 20% of the total mass of the product.

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!

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.

Sergei Odintsov

electrod.biz

What electrodes are needed for welding pipes, profiles and other metal structures

There is an erroneous opinion that the 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 work.

First of all, it should be noted that such conductive rods can be both metallic and non-metallic, that is, carbon or graphite, but in this case, the second type does not interest us.

A good welder always knows which electrodes to weld pipes with.

Let's look at what signs you can distinguish between consumables of this type, how best to choose them, and the video in this article will demonstrate visual information on our topic.

How they are distinguished

The photo shows a wire for welding

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

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

In addition, the electrodes are classified according to their purpose, that is, 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.

Tungsten - TIGWIG

In most cases, there is a coating on the rods, but it also differs and has its own marking in accordance with GOST 9466-75.

For example:

• thin coating is marked with the letter A (international format - A);
• middle - letter C (international format - B);
• thick - letter D (international format - R);
• and especially 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 - main;
• C - cellulose;
• R - rutile;
• P - mixed.

In addition, the mixed layer can be:

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

Note. Due to the fact that welding work can be carried out in different positions, the electrodes are classified into different types here. So, they can be for the lower position vertical from the bottom up, horizontal and lower into the boat.

The instruction also implies rods for any position.

By appointment. Types of materials

High pressure gas pipe welding

• Carbon and low alloy structural steels. In this case, the tensile strength can be up to 60 kgf/mm or 600 MPa.
• High-alloy types of steel, 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 a surface layer of metal having special properties.
• Cast iron.
• Nonferrous metals. (See also the article Sewerage in a cottage: features.)

More about coverage

Various coatings

• A - acid or acid coating. It consists of oxides of iron, manganese and silicon.
• B is basic. It contains calcium fluoride and calcium carbonate. Welding work with the help of such electrodes is carried out with direct current of variable polarity.
• C - cellulose. It contains flour and other organic components that are intended to create a gas protective shell in the production of welding work.
• R - rutile. It contains rutile as the main component, as well as 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 somewhat simpler, since there, usually 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 what electrodes to weld a profile pipe with, then given the thin wall of the profile (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

Vertical connection without beveled edges

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

Consumption of electrodes when welding pipes per meter of seam

Consumption of electrodes when welding pipes for 1 joint

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

Conclusion

As you noticed, there are a lot of brands of electrodes, 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, as well as cast iron.

In addition, the thickness of the walls of heating pipes, as a rule, is not less than 2 mm, then a 3 mm rod is needed. In addition, you will find an electrode for all positions, with a medium crack (C) type, acid (A) or basic (B), for carbon and low carbon steels.

There is an erroneous opinion that the 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 work.

First of all, it should be noted that such conductive rods can be both metallic and non-metallic, that is, carbon or graphite, but in this case, the second type does not interest us.

Let's look at what signs you can distinguish between consumables of this type, 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 or non-consumable. The first type can be coated, with a steel, cast iron, bronze, copper or aluminum rod, but the uncoated ones are currently used only in the form of a wire (see photo above) when welding is carried out in a gas protective environment.

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

In addition, the electrodes are classified according to their purpose, that is, 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 alloyed and heat-resistant steels - with the letter T, but for the deposition of the surface layer - with the letter T.

Tungsten – TIGWIG

In most cases, there is a coating on the rods, but it also differs and has its own marking in accordance with GOST 9466-75.

For example:

• thin coating is marked with the letter A (international format - A);
• middle - the letter C (international format - B);
• thick - letter D (international format - R);
• and especially 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 - main;
• C - cellulose;
• R - rutile;
• P - mixed.

In addition, the mixed layer can be:

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

Note. Due to the fact that welding work can be carried out in different positions, the electrodes are classified into different types here.
So, they can be for the lower position vertical from the bottom up, horizontal and lower into the boat.
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 have 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.)

More about coverage

• A - acid or acid coating. It consists of oxides of iron, manganese and silicon.
• B is basic. It contains calcium fluoride and calcium carbonate. Welding work with the help of such electrodes is carried out with direct current of variable polarity.
• C - cellulose. It contains flour and other organic components that are intended to create a gas protective shell in the production of welding work.
• R - rutile. It contains rutile as the main component, as well as 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 somewhat simpler, since there, usually 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 what electrodes to weld a profile pipe with, then given the thin wall of the profile (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 heating installation, the consumption rates of electrodes when welding pipes can be different, depending on the type of seam, but we will consider only a vertical connection without beveled edges, as the most commonly used.

Consumption of electrodes when welding pipes per meter of seam

Consumption of electrodes when welding pipes for 1 joint

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

Conclusion

As you noticed, there are a lot of brands of electrodes, 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, as well as cast iron.

In addition, the thickness of the walls of heating pipes, as a rule, is not less than 2 mm, then a 3 mm rod is needed. In addition, you will find an electrode for all positions, with a medium crack (C) type, acid (A) or basic (B), for carbon and low carbon steels.