Welding electrodes marking and purpose. Electrodes for surfacing

When working with manual electric arc welding, you constantly work with electrodes. This element of the welding process is not so simple as it seems and has its own extensive classification. Today, you can choose products for any needs, based on the welded metals, the type of equipment, the necessary properties of the seam and the set of auxiliary parameters. Below you read the classification of coated electrodes and their designation.

Electrodes applicable to manual arc welding for work are divided into melting and uncomplicated. Rods melted with welding are made of cast iron, steel, copper or other metal, depending on the material. They play the role of an anode or cathode, and also perform the function of the additive material. There are covered or uncovered.

The covering in the melting rods performs many functions from the hold of the arc, before the formation of a gas cloud that prevents the oxidation of the seam.
Uncompaired electrodes for welding, made from various refractory materials - graphite, tungsten or coal. They serve to ignite and retention of the arc, and the filling of the seam by additives is performed using a manual supply of fusible material.

What is the melting electrode

Melting electrodes for manual arc welding consist of an internal rod and an outer layer. According to the requirements of the State Standard, the creation of melting electrodes of welding uses a variety of steel: carbon, with a large or small number of impurities, copper, aluminum, nickel and other colored alloys are also used. The composition of the rod is due to the weldable material, as both metal must approach each other. The exception is cast iron, which can be welded both steel and electrodes from copper and iron.

Like the rod, the outer layer is manufactured taking into account the welded metal, which is why its composition can change somewhat. But despite this, it consistently performs the following functions:

• contributes to the deduction of the arc;
• produces slag enveloping welding bath, melting mineral coating components;
• produces protective gas that appears as a consequence of combustion of organic coating components.
• performs deoxidation or doping of metal.

Classification of coated electrodes

Given the long list of all sorts of variations from the coating, alloy and other parameters of the coated electrodes, for a more convenient search for the desired type of rods, they received an extensive classification. Types of welding electrodes are divided based on such signs:

For appointment:

• alloys with a small fraction of impurities and carbon alloys;
• material with a large number of ligatures;
• strengthened strength and unique properties;
• swimming electrodes with unique properties.

Type - the value of the final seam, characterized by tensile strength, temporary or point mechanical impact.

The brands of welding electrodes are a unique value assigned by the manufacturer for the internal classification of products. That is why the labeling of electrodes for welding the same parameters, but from various manufacturers can be different.

The thickness of the outer layer is based on their thickness ratios, to the size of the central bar, the outer layer is classified into - thin, medium thickness, thick and the thick.

Current gene - DC electrodes, Direct or reverse alternating.

The composition of the coating is separated by a welding electrode with an acidic, basic, cellulose, rutile, a layer with an increased iron concentration, spraying consisting of various layers.

According to the allowable positions, the rods are divided into products permissible to work in:
· Any positions;
· All with the exception of vertical, directional down;
· The bottom and vertical direction to the top;
· Lower.

In terms of quality or by the state of the seam, after working with rods, the electrodes are divided into three groups. Best quality products belong to the first group.
Thickness - the parameter indicating the diameter of the steel base may be in the range from 1.6 to 12 mm.

Marking of welding electrodes and their decoding

To deal with what electrodes are presented in front of you should examine them marking. Each package contains information about 9 basic characteristics according to GOST 9466-75.

1. Types coated electrodes for welding.
   High-strength steel, with a large carbon fraction, high or low percentages of ligatures, are equipped with electrodes with marking, starting with the E - electrode symbol, then there are numbers indicating the maximum allowable stretching loads (kgf_mm2), at the end there is an index A - denoting increased resistance Seam to plastic and shock loads. For example: E 42, e 50, E46 A, E 60, and TD.
   Heat-resistant and high-alloy steel: symbol e, numbers after a dash indicating the amount of carbon, followed by letters and numbers - indicating a specific chemical element (A - Nitrogen, M-Molybdenum, F - Vanadium and TD.) And its number in hundredths . Chemical components are located in descending order of their quantity in the product. For example: E-09M; E-10khsm1bf; E-30G2XM and TD.
2. Brands Electrodes for welding
   Marks - the parameter is individual and depends exclusively from the manufacturer.
3. Diameter
   The thickness of the inside of the coated electrode ranges from 1.6 to 12 mm, the thickness of 3-5 mm are most often used.
4. Purpose
   Made to work with carbon steel and with a low number of impurities, as well as strength up to 60 kgf / m2, the electrodes are marked with the letter - y;
   Alloyed structural steel with a strength limit above 60kgs / m2, welded with marking products - l;
   Products for steels with a low heat transfer coefficient labeled the letter - T;
   Metals with a large fraction of impurities and unique properties can be welded with marking products - in;
   Surfacing layers with unique characteristics are made by product with marking - N.
5. Coating thickness
   The value showing the ratio of the thickness of the coating to the inner rod. If this is less than 1.2, then the product is marked with a symbol M and refer to thinly coated; The average layer in the range from 1.2 to 1.45 is marked with a symbol with; Thick - from 1.45 to 1.8 noted by the symbol of D and finally the thickest, whose ratio is more than 1.8 marked with a mark of G.
6. The main properties of the seam
   The exact properties of alloys, for each type, these values \u200b\u200bare their own and indicate strength, the percentage composition of impurities, the operating temperature of the seam and a number of other indicators. These values \u200b\u200bcan be found in the corresponding tables with decodes.
7. Type of electrode coating
   A - acid coating.
   B - fluorinist-calcium.
   C - cellulose.
   R - rutile.
   Well - elevated iron content.
   There are also mixed types of coating electrodes that are marked with several letters based on the composition.
8. Marking of spatial positions
   1 - all
   2 - everything except vertical downwards;
   3 - lower, plus vertical (bottom-up movement);
   4 - exclusively lower.
9. Ring of welding current and connection
   - index 0 DC electrodes and reverse connection;
   - index 1,4, 7 - indicates products for any kind of voltage generations and any connections;
   - pointers - 2,5,8 - Current any, but the connection must be direct;
   - Indexes - 3,69 for any currents and reverse connection.

Manufacturers of welding electrodes

Below, presents the top three manufacturers of welding coated electrodes of Russia:

1. NPP "Welding of Eurasia". For more than 70 years of history, the company managed to master the full cycle of the production of electrodes and at the moment produces all types of electrodes - melting, welding, for alloyed steels and many others.
2. CJSC "Electrode Plant". The manufacturer is famous for its products that are supplied to the largest engineering plants of the country, the company also produces products for the ordinary consumer. Professional welders celebrate the convenience of work and product quality of this company.
3. LLC NPO Special Electrod. Products of this company are more than 50 different grams of consumer rods thick up to 6mm. Also, production takes individual orders.

Do not forget about the world leaders, the top three:

1. ESAB is a company with century-old history and products recognized as the best in the world. These Swedish electrodes know on all continents as the highest quality.
2. Kobe Steel is a Japanese company who has gained popularity through the supply of their products to oil producing enterprises.
3. Klöckner & Co SE is a German company producing steel and consumables for welding. Electrodes for welding this company are very popular and widely used in Russia.

Welding works are used for high-quality durable compounds of metal structures and alloys. At the same time, it is important to correctly pick up the brand of the electrode. To do this, you need to know the classification of electrodes, their labeling methods, areas in which they are recommended to be applied.

Two large groups of electrodes make up melting and uncomplicated, in turn melting electrodes are divided into some subspecies, such as covered or unlocked (wire).

Melting electrodes

By type of welded or weed steels, several types of electrodes are provided:

for welding carbon steels (marking - "y"). These are electrodes E38, E42, E46, E50.

alloyed (marking - "l"). These are electrodes E70, E85, E100, E125, E150.

heat resistant (marking - "T"). Welding of such steels is carried out with pre-heating and final thermal processing of seams. Usually use electrodes that are not described in GOST (for example ANZhR-2).

for steels, with special properties, such as corrosion-resistant, heat-resistant, heat-resistant (marking - "B"). The list of types of electrodes is regulated by GOST 10052-75.

for the surfacing of the surface layers of the metal (marking - "H"). These are electrodes E-09M, E-09MX, E-09X1M, E-05X2M, E-09X2M1, E-09X1MF, E-10X1M1NFB, E-10HSM1BF, E-10X5MF.

Melting coated (unwinding) electrodes

Coating or coating on welding electrodes are applied to ensure good ignition and sustainable burning of the arc, protection of the welding bath from the environment, to obtain the desired properties of the seam, reduce the losses when spraying, increase the speed of welding, reduce the toxicity of gases secreted during welding, eliminate the loss of properties Coatings when stored.

In the thickness of the coating (coatings), by calculating the ratio of diameters D (coated electrode) and D (rod) electrodes are divided into:

• tonclock, with a ratio d / d to 1.2, denoted by the letter "M";
• electrodes coated with medium thickness, D / D to 1.45 are denoted by the letter "C";
• thick-coated (otherwise, high-quality), D / D from 1.45 to 1.8 are indicated by the letter "D";
• with a particularly thick layer of coating, D / D is greater than 1.8, marked with the letter "g".

By type of chemical station, there are several types of coating electrodes:

• Electrodes with sour coating (in composition there are iron or manganese oxide). This type of coating is characterized by a high arc temperature, respectively, high welding speed, however, manganese oxide is very toxic and dangerous when inhaled. Denote by the letter "A" (DIN - A).
• Rutile coating electrodes that contain titanium dioxide are characterized by a calm welding bath, a small amount of splashes, which allows to impose thin seams on the welded parts. Denote by the letter "P" (DIN - R). The mixed coating electrodes are also common to which rutilo-pulp (RC), Rutilovo - the main (RB), Rutilo - sour (Ra) and rutile with iron powder (RJ). (DIN - RC, RB, RA and RR, respectively).
• Electrodes with main coatings (denoted by the letter "B", DIN - B) contain calcite, carbon dioxide and in small amounts fluorite. Such covers are sensitive to moisture, so it is necessary to respond to the conditions for their storage. However, the seam, obtained by using these electrodes, has excellent mechanical properties, devoid of cracks to the appearance of cracks and aging and practically does not contain nitrogen and oxygen. These electrodes are welding the most loaded and responsible structures.
• Electrodes with pulp coating (denoted by the "C" index) contain organic substances that, when combustion, envelop the welding bath with protective gases. They are used when working mainly with high-strength structures, pipelines. They are used in more often for welding vertically spaced seams, however, they form a large number of splashes during operation.
• Electrodes, in covering the iron powder are present, are used when welding online zazes. When using such electrodes there is a stable burning of the arc, there are practically no spray, the welding seam is cooled faster, the appearance of a slag is reduced to a minimum that is easily separated from the metal.

In the marking of the electrode, a pointer is necessarily present (in the form of numbers from 1 to 4), or an international designation (scheme) on the spatial position of the welding seam:

1 - any position;

2 - anyone except vertical from above-down;

3 - lower position, horizontal and vertical bottom-up;

4 - the bottom or angular compounds below the "boating".

If the position of the welding seam is indicated by the scheme, the arrows indicate its direction in space.

When selecting electrodes for different welding modes, it is necessary to take into account the polarity of the DC source and the nominal (basic) voltage (UXX) of the idling power source (AC). These parameters on the electrodes are denoted by the number from "0" to "9":

GOST 9466-75, regulating the manufacture and marking of melting electrodes, requires that the packaging contains all the necessary information:

- - -

E - -

In the position "1" denotes the type of electrode.

Then, in the position "2" indicates its brand.

In the position "3", or the diameter is clearly written (in mm.), Either put a sign Ø, which means that the diameter is specified separately.

Positions "4" and "5" are intended to indicate the appointment and thickness of the coating.

The position "6" indicates the index.

The type of coating for chemical composition is listed in the position "7".

In the positions "8" and "9", respectively, the position of the seam in space and a figure denoting the generation of the welding current is indicated.

For example:

From the marking it is seen: the type of electrode - E46, the brand - "LESMR-3C", the diameters are indicated in the table, the electrode with a thick coating (otherwise called high-quality) is used for welding in any position of carbon steels. At the bottom of the marking it is indicated that the electrode with a rutile-cellulose coating is possible, both alternating current and constant reverse polarity are possible.

Tables of various indexes (position "6") for the characteristics of the metal seam or surfacing of various types of steels are listed below:

These indexes reflect various characteristics and properties of the seam or the catch (immediately after welding, without heat treatment), such as shock viscosity, elongation, or resistance to the rupture specified by the electrode type. Information is taken from GOST 9467-75.

Unlocked melting electrodes

Currently, electrodes without coating (or welding wire) are widely used. For technical conditions and GOST (2246-70), about 80 of its species are defined. However, in domestic needs for welding metal structures from ordinary rolled or stainless steel, units are used. The wire is divided into doped (presented in GOST 30 stamps, contains up to 10% of alloying elements), low- (6 types, with the content of alloying additives up to 2.5%) and high-alloyed (41 brand in GOST, the content of alloying impurities exceeds 10%) Depending on the percentage of the degree of alloying.

Welding wire is denoted by the letters of "SV" at the beginning of the labeling. Then there is a designation of hundredths of the carbon percentage, after the name and percentage of alloying (s) elements are indicated. If the percentage ratio is not explicitly indicated, then it is in the range from 0.5 to 1%.

Alloying impurities in the composition of the wire are indicated as follows:

Also at the very end of the labeling there may be one or two letters "A", which means a high and very high degree of purification of steel used.

Thus, the labeling of the Wire 3 SV04X19N9 means a 3-millimeter melting electrode with a carbon content - 0.04%, chromium - 19% and nickel - 9%. Wire with chrome and nickel in composition (in the table indicated by an asterisk) is used for welding of doped steels resistant to corrosion (stainless steel).

Unqualified electrodes

Tungsten

Tungsten electrodes are designed for welding, cutting mainly in the environment of protective gases, such as argon, helium, nitrogen, or mixtures thereof. In addition to the tungsten, the electrode may contain various impurities that increase its wear resistance. This type of electrodes provides high stability of the welding arc and allows you to work with any metals and alloys.

Coal

There are also other species of uncompromising electrodes, including coal and graphite ones. Considering that coal - soft material, consuming is used to improve the quality and safety of the coating in them. They are used mainly to work with thin metals, as well as for surface cutting, edge processing, rigs, etc.

Several types of graphite or coal electrodes are manufactured, including round, connected (endless, with nipples), flat and semicircular. Round and endless electrodes contain in marking the diameter of the electrode from 3 mm to 25 mm, flat can be represented by square or rectangular, with different cross section. In semicircular (the most universal) indicate the size of the flat side, the radius of the circle and the length of the electrode.

There are also hollow electrodes that are used exclusively for rings, they are manufactured mainly by foreign companies.

The popularity of welding is due to the relative simplicity of the process, as well as low financial costs at a high level of quality. There are a variety of electrodes brands for manual arc welding. They are selected according to exactly which metal will have to weld, as specialists try to achieve identity between the metal of the rod and the workpiece. In addition, there are a number of factors that affect the external conditions, which accompany the compound process. It is these conditions that create a situation, thereby exist different types of electrodes for manual arc welding.

Often they have a coating that supports stable burning of the arc and creates protection against the negative impact of external factors. There may also have many differences that make them suitable for certain conditions, but often they also depend on what metal products are intended for. The same brands can be made by various manufacturers, the main thing is that the production standards have been met, which will guarantee the receipt of the declared specifications.

Types of electrodes for manual arc welding

Electrodes for manual arc welding can differ in several signs. First of all, they differ in purpose:

• For welding steels with a low content of alloying elements, as well as with an average carbon content. As a rule, they have a gap resistance of about 600 MPa. In the marking, they are denoted by the letter "y".
• For welding doped steels with a high degree of heat resistance. In the marking, they are indicated by the letter "T".
• For welding structural steels with the content of alloying elements. The resistance to the rupture also has about 600 MPa.
• To burn surface layers on metals with special properties. They are denoted by the letter "H".
• For welding steels with a high content of alloying substances and possessing special properties.
• For welding metals with high plastic properties. Contain the letter "A" when designated in marking.

Exterior view of electrodes for manual arc welding

The classification of welding electrodes for manual arc welding can also occur along the thickness of the coating. They depend on the diameter of the metal rod, but the varieties concern exactly this ratio, and not absolute size. Select four main types:

• Thin coating "M". Its thickness is about 20% of the diameter of the rod;
• Average "C". Thickness is about 45% of the diameter of the rod (the most common option);
• Tolstoy "d". Thickness is about 80% of the diameter of the rod;
• Particularly thick "g". Thickness more than 80% of the diameter of the rod.

It is also isolated depending on the presence of coating and variety. It is worth noting that they are found not only in pure form, but also in a variety of combinations, where the main components are included in the composition of the main components. Coating electrodes for manual arc welding are designed for a protective function that inert gas performs in gas welding. Clean types can be classified as:

• "A" - sour;
• "B" - the main one;
• "C" - cellulose;
• "R" - rutile;
• "P" - Others (this does not include double types, such as the RC, BC and Other, which are allocated separately).

Electrodes for may have limited use in spatial position. The fact is that some of them are too fluid, therefore, with the ceiling position, they will simply be able to contact the right place, but will flock down. To make it clear which brand for what is intended, the designation of the electrodes of manual arc welding contains an item on the spatial position:

• "1" - can be used in all possible positions;
• "2" - all provisions are available except for the vertical, leading from top to bottom;
• "3" - for horizontal and vertical, excluding the ceiling position;
• "4" - only horizontal varieties are acceptable.

Table of brands of electrodes and applications for manual arc welding and alkali steel

Some types of electrodes are initially created under work with certain technical metals. Alloy steel are often used in production, so that consumables produce consumables specifically under their properties. They contain the same alloying elements that are mainly metal to compensate for their disadvantage after temperature effects.

Table brands of electrodes and scope for manual arc welding and cast iron

The choice of electrodes for manual arc welding of cast iron depends on carbon content in this metal. In any case, it is high enough and therefore consumables also contain this element, which highlights their properties with respect to other electrodes.

Table of electrodes and applications for manual arc welding and surfacing non-ferrous metals

Colored metals are rarely found than steel. Electrodes for them are intended for both pure metals and alloys. Here it is necessary for the presence of a large number of the main element in the composition, since many of the parts are difficult to weld.

Table of brands of electrodes and scope for metal cutting

Such types of materials are unique, since heating and melting electrode under arc welding in an ordinary case occurs during the average modes, while these need to be used at maximum current. They have increased heat resistance, but they still belong to fusible options.

Designation and marking of electrodes for manual arc welding

On the example of the E-46 electrode Lazano21 UD E 43 1 (3) RC13

• E-46 - type, for low-alloyed and carbon steels;
• Lazano21 - brand;
• Y - appointment, for low-alloyed and carbon steels;
• D - thick coating;
• E - melting electrode;
• 43 - tensile strength - 430 MPa;
• 1 - relative elongation of about 20%;
• (3) - 20 degrees Celsius to preserve shock viscosity;
• RC - Rutil-pulp coating;
• 1 - spatial positions, all are allowed;
• 3 - Current for welding, can be prepared by a constant current of reverse polarity and variable at idle in 50 V.

Exterior of the E-46 Electrode LEZ ANO-21

Choice

The priority factor in the choice is a metal in the rod. It should be similar to the one from which the workpiece is made. For manual arc welding goes the following item, as they should not exceed the thickness of the most details. The coating is selected according to which conditions have to work. Before the final choice, it is necessary to study the label in detail to make sure of its correctness.

"IMPORTANT! Before using the electrodes, they need to dry and rolling."

Choosing electrodes for welding, you should pay special attention to labeling. The fact is that there is the most important information about the acquired electrodes, including the manufacturer, composition and other characteristics. If you focus on this information, the task is simplified by the choice of the most suitable material, which will provide a qualitative result when working under certain conditions with plans to compound metals and alloys. To do this, before making a solution, it is necessary to carefully study the signs that are located on the packaging.

Welding electrodes

As the main consumable material for manual arc welding, with the use of which today metals are most often and welded, electrodes are used. In its execution they look in the form of a metal rod Or a product made from another material that can cover or not have it. One end of the rod necessarily has a coating. It is this side of it and placed in the electricallyer.

During the execution of welding work on a plot formed by the end of the electrode and the treated surface, an electric arc is formed. The process of connecting surfaces using welding equipment under conditions of elevated temperatures, with the substance, using which melting is performed, are being carried out too intensive interaction with respect to each other.

Advantages of electrodes

Electrodes are the most preferred consumables for welding the following reasons:

• their use allows you to create a smooth weld, having no pores and devoid of unreasonable sections.
• the ignition of the arc does not require great effort. Also does not arise problems and with its maintenance.
• the use of electrodes allows you to create a uniform coating based on slag, which without much effort can be removed after the end of the welding work.

The main purpose and composition of welding electrodes

In its execution, the electrode has a form of a rod made of metal or other material, thanks to which the current reaches the welded product. For this reason, the material being processed should be highlighted by high electrical conductivity. Most often, such structures are based on wire and alloys with different levels of alloying.

To give a product of the required characteristics, it provides a special coating. Thanks to him the electrode perfectly transfers the impact of gasesFirst of all, nitrogen and oxygen, and also helps to maintain the stability of the burning of the arc, combat harmful impurities contained in the molten metal. The use of the coating is that the metal or alloy used for welding is enriched with the necessary alloying elements.

In general, it can be noted that certain components should be present to ensure the electrodes of the necessary properties.

An important role is assigned to slag-forming substances, for example, chalk, mramor, due to which high protection against negative impact on the side of nitrogen and oxygen, whose harm is to exposure to oxidative processes. It is possible to get rid of the molten metal from oxygen by means of such substances as titanium ferroalloys, manganese, aluminum and silicon. The latter represent a group of deoxidizing substances, due to which the required result is ensured.

To create a protective gas environment use special gas-forming components, the most vivid representatives of which are wood flour and dextrin. The task of making the suture of exceptional characteristics in terms of resistance to wear, not exposure to the influence of corrosion, is solved using the introduction of special alloying additives.

The list of these components is quite large, so we will give only some of them: chrome, titanium, nickel, vanadium, etc. The group of stabilizing substances form potassium, sodium and calcium. Their basic effect is to ensure the ionization of the welding arc. To create a reliable connection between each component of the coating and the electrode rod special binders must be appliedWhich is most often used silicate glue.

Marking of electrodes for welding and requirements for them

The classification of electrodes implies their separation into two types:

• melting;
• unqualced.

The first group includes items manufactured based on materials such as steel, copper, cast iron and bronze. A distinctive feature is the presence of additional coating. The special group is formed by melting uncoated elements, however they got the greatest distribution as a wire for welding designsimplemented in the protective gases environment. The category of non-comprehensive varieties of electrodes for welding include products created on the basis of materials such as tungsten, thorium and lanthanum.

Another feature of the classification of electrodes for welding can be the type of coating. Products in which the label is present in the marking, refer to the class of products with sour coating. Similar electrodes undesirable to apply for weldingcarried out for the compound of steels characterized by the high concentration of carbon and sulfur. If we talk about a spatial position, there are no restrictions here. Except here is the placement vertically when the electrode is brought from top to bottom. The most frequently detected defects are the appearance of severe splashes and the risk of seam cracking.

To refer to the base coating, the letter B. B. Electrodes for welding with such marking should not be used for welding in a vertical position. The same applies to those products that have a rutile coating, which indicates the letter R. If the marking contains the letter C, then this is a prompt about the use of cellulose coating. Such electrodes retain their operational characteristics in any position.

If we talk about their minuses, then here should be attributed formation of strong splashes and overheating riskWhat is why they require special attention while working. The latest group of electrodes form products with labeling of the AC and RB. They represent a combined version to which resort to connecting pipelines and structures of various purposes. Working with them, it should be remembered that they are unacceptable to post them in the ceiling position.

Having become acquainted with the peculiarities of these elements and their design, you can proceed to the requirements that they must match. Let's say for any electrode for welding, it is important to create favorable conditions.In which the arc will burn consistently, which in turn will ensure uniform melting of the metal. In addition to this, the created seam must meet the requirement of its chemical composition. The latter can provide for various components, which is determined by the operating conditions of the part and the composition of the metal products that must be connected.

Decoding Marking Electrodes for Welding

It is time to get acquainted in more detail with the same information hides the marking of electrodes for welding. It always begins with characters that correspond to the type containing a maximum load tip. For example, E46 suggests that the maximum load is 46 kg / mm 2 for welded parts. A brand is already underway for it, reporting on the manufacturer, and after it provides information about the thickness and purpose:

• the presence of a letter in the marking indicates that the electrode under consideration is suitable for welding products made on the basis of low-alloyed and carbon steels;
• the marking that contains the letter L says that these electrodes can be used to connect alloyed structural alloys;
• if there is a task for connecting structures made on the basis of heat-resistant or high-alloy steels used for welding the electrode must have the designation T and B;
• qualitatively perform a layer surfacing that must have exceptional properties, under the condition that the electrode used is labeled in the form of the letter N.

Thickness, diameter, current

Also in marking is given a hint of the thickness of the coating, for which the following notation is provided:

• M - means a thin coating;
• C - average coating;
• D - it corresponds to a thick coating;
• G - indicates the presence of a coverage of the maximum thickness.

Next, the label provides information about diameter. Sometimes it may not contain numerical designations, this information can only be brought in the form of an icon. In this case, it is necessary to conclude that the necessary data is shown on the press. The following symbols are the index and its meaning, which can be understood by the characteristic of the metal. We are talking about such properties as relative elongation, shock viscosity and rupture resistance. To obtain more accurate information about these parameters, you must contact GOST 9467-75.

At the very end, information on the type of coating is discussed above. According to the last two digits, it can be understood which spatial position is provided for the electrode of a particular brand and which recommended indicator must have a working current.

If there is a number 1 there, the selected electrode is suitable for operation in any position. 2 indicates the lack of restrictions with the exception of the position from above-down.

Sometimes the penultimate comes figure 3, which suggests that this electrode is prohibited to be placed in the ceiling orientation. The presence of Figure 4 indicates that the product is intended to perform the lower seams, as well as the lower in the "boat".

• 1, 4, 7 - indicates the absence of restrictions;
• 2, 5, 8 - applies to currents with straight and other polarity species;
• 3, 6, 9 - provides that the current must have reverse polarity.

Conclusion

The execution of welding works is impossible without using such an important consumable material as electrodes. This can not be understood as its meaning, since the quality of the compounds of the processed surfaces depends on the right choice.. The presence of various labels of the electrodes already suggests that they have a different purpose. For this reason, it is important to have an idea of \u200b\u200bwhat that or that labeling means. Knowing about such designations, you can easily understand which electrode is suitable for welding and make a sure choice.

» Coatings of electrodes

The electrode for manual arc welding is a metal rod with a protective coating-coating. The components of the coating ensure the protection of the welding zone from air oxidation, contribute to the increase in ionization. Rods with coating are used both for ferrous and non-ferrous metals, as well as alloys.

Purpose of coating electrodes

The main task that manufacturers are placed on the coating of electrodes for manual arc welding are melting Metal Protection. They protect the melting metal from interacting with air, preventing oxidation, make the finished seam quality and durable.

When working with the welding machine, a protective coating creates a shell of slag on the droplets of the electrode metalmoving along the arc gap, as well as on the melting surface of the details welded to each other.

Slag protective layer reduces the speed with which the metal cools, and the speed of its curingThrough it, gas and other inclusions have come out of it, which negatively affect the strength of the structure. As a rule, protective spraying consists of a whole complex of slag-forming elements, such as kaolin or titanium concentrate.

What functions provides high-quality coverage

The coating covering the rods from the metal performs a number of major and secondary tasks. Of paramount, you can allocate:

Minor, but equally important tasks:

• ensuring uninterrupted burning of arc in a wide range of operation modes, simplifying the ignition process. The stability of the arc is implemented due to the presence in the surface layer of the components, which are not prone to ionization in a large volume. This contributes to an increase in the number of ions that stabilize the burning in the arc space;
• removal from metal welding bath dissolved in it oxygen. For this, ferroalloys are added to the composition of the coolant, which are easier and faster than the metal itself, come with oxygen into the reaction;
• cleaning metal seam from impurities (refining).

Diameter of coating

You can find a lot of brands of electrodes intended for different types of metal and the strength of the alleged loads on the future design. Rods with coating have two diameter values: the diameter of the electrode itself and the total diameter of the rod and spraying. When choosing a suitable variant, the diameter is one of the defining factors: than it is more, the greater the thickness of the metal can be connected using a rod.

Important! The mode of operation of the welding machine is exhibited, based on the thickness of the parts of the parts and the diameter of the straighter. It is important to correctly calculate the strength of the current, since with too strong current the metal you can just burn through, and with too weak it will not be able to form an arc.

The diameter of the sharpness with the coating affects not only the ease of working with the material during welding, but also provides the desired characteristics of the compound performed, affects the strength of the resulting structure.

Letter "E" In the marking means a piece electrode, universally used for manual arc welding at home.

Letter- the minimum value of the guaranteed temporary resistance to the seam break. The greater this number, the larger loads will withstand the welded item.

For example, E42 type products provide an impedance of at least 42 kgf / mm2, and straightening with E46 marking - at least 46 kgf / mm2. E42a electrodes are used for metal with similar qualitative indicators for a gap, but in conditions where higher parameters of the shock viscosity and relative elongation of the obtained seam are needed. The improved characteristics says the letter "A" in the marking, which indicates the sour type of rod coating.

Coating thickness

Blue coating electrode brand

In addition to the characteristics of the coating applied to the electrode rod and the diameter of the electrode itself, during the selection of materials for welding, they are also focused on the thickness of the protective coating.

The thickness of the cooler of the electrode rod is the ratio General diameter (d) and diameter of the inner rod (D). That is, a thicker electrode may have a smaller coating thickness if it has a smaller value of the d / d ratio.

For each diameter of the inner rod, there is its own thickness thickness. There are 4 categories of electrodes, differing thickness of the coating:

1. thin or stabilizing electrodes (for their designation, the letter M) is used with a ratio of 1.2 or more;
2. middle electrodes (denoted by the letter C) with a ratio of 1.45 or more;
3. thickhaving a ratio less than or equal to 1.8, which are still called qualitative (marked with the letter D);
4. particularly thick The electrodes are also included in the category of high quality and have a ratio of diameters over 1.8 (can be found in the letter G in marking).

The thickness of the high-quality electrodes is fluctuated in the range from 0.5 to 2.5 mm, which is 20-40% of the mass of the inner rod. If we take into account the iron powder, then the diameter will be 3.5 mm, and the mass fraction is 50%. Such electrodes are used when a high-quality seam needs can withstand heavy loads.

Thin or stabilizing electrodes, the thickness of the coating of which is about 0.1-0.3 mm, make the burning of the arc is flat and continuous, but do not affect the qualitative indicators of the welded steel.

Types of coating electrodes for manual welding

Consider what coatings of the electrodes are, their components and how is it referred to. Four exist basic species of coatings used in the production of electrodes for welding:

1. coating acid type indicated by the letter A;
2. basic (B) coating;
3. cellulosic coating (C);
4. rutile (R).

The coating of welding electrodes is selected on the basis of which type of steel is planned to be cooked, the load for the design and other factors.

Sour

The main advantage of coating acidic type - with welding works the probability of pore formation in the seam region is striving for zeroEven if the seats welding elements to each other. The acidic coating contributes to the uniform burning of the arc and the light ignition. This type of electrodes use when the requirements for the finished design minimal.

Rods with acidic protection work well both at constant and variable Toky. The most tangible flaws are splashes during welding, toxic evaporation, the risk of hot cracks when welding.

CAUTION! The acidic coating is toxic when heated!

Basic

Due to the weak oxidation of such a coating, it contributes to a slightness of the melting metal oxygen. Seam made using the electrode with the main coating, protected from hot cracks. Electrode of this type need to hide Before working to eliminate the likelihood of pores in the seam. Due to the complexity of maintaining the burning of the arc, the welding electrodes with the main coating is needed only using the source of the DC reverse polarity (it does not apply to all, but to most brands).

The electrodes with the main type of coating are used for welding metal parts from ironing steel species, which are at risk of cold cracks, as well as for welding metal elements with a large percentage of sulfur and phosphorus. "Main" electrodes show high efficiency when welding in several layers of structures that need high rigidity.

Cellulose

Use in working with a welding machine of products with collulose coating (have a "C" labeling on the package) gives good quality burning of the arc mainly at constant current. This type is used when welding root seams on trunk pipelines made of low carbon steel.

Also rods with cellulose coating excellent suitable for one-sided welding with high-quality regulation in the root seam area. The use of rods gives a good result when welding carried out in a vertical position.

It is not recommended to use steel welding having a high carbon percentage and other alloying components in the composition. Another minus is a high degree of susceptibility to high temperatures and the probability of splashing molten metal during operation.

Rutile

This type of coating is indicated by the letter "P". Rods covered with rutile composition show good results Even or traces of scale on the surface in places of welding, in the process of connecting parts, hot cracks are not formed.