How to choose the correct electrode diameter

Selection of welding current depending on the diameter of the electrode | Welding and Control

The welding mode is understood as a group of controlled parameters that determine its conditions. The welding mode parameters are divided into basic and additional.  

The main parameters of the manual welding mode include current strength, type and polarity of current, arc voltage, electrode diameter and welding speed. Additional parameters include the composition and thickness of the electrode coatings, the position of the electrode and the position of the product during welding.

The most important and primary stage in determining welding modes is the selection of the diameter of the electrodes. The diameter of the electrode is selected depending on the thickness of the metal and the spatial position of the weld and the type of connection.

The approximate relationship between the metal thickness S and the diameter of the electrode when welding a seam is given in the table below. The spatial position in which electrodes can be cooked is indicated on the pack.

For more information about the designation of the characteristics of electrodes and their decoding, read the article Coated electrodes, characteristics, technical requirements. Classification, marking GOST 9466-75

Vertical, horizontal and ceiling welds, regardless of the thickness of the metal, are welded with an electrode diameter of usually 3 mm to a maximum of 4 mm in order to avoid drainage of liquid metal and slag from the weld pool.

Also, the root of the seam is made with electrodes with a diameter of no more than 3 mm, to ensure complete penetration, and subsequent layers of the seam are made with electrodes of a larger diameter.

Setting the current depending on the diameter of the electrode

The strength of the welding current is selected depending on the brand and diameter of the electrode, taking into account the position of the seam in space, the type of connection, the thickness and chemical composition of the metal being welded, as well as the ambient temperature.

Welding current is one of the main parameters of the welding process, on which the quality and reliability of the resulting weld depends.

When taking into account all these factors, it is necessary to strive to work at the optimal possible current strength to ensure a stable welding process.

Important: Welding current and electrode diameter are interrelated.

The choice of welding current must be approached responsibly!
Incorrectly selected welding current will lead to defects. If the current is too high, the welded parts will burn through. If the welding current is insufficient, the metal will not melt, resulting in lack of penetration and lack of fusion. There is nothing complicated in choosing a welding current.

Recommendations for choosing the current strength can be found on the pack of electrodes or in reference books and regulatory documents. Recommended average welding current values ​​are given in the table below.

Depending on the spatial position of the weld, the current value must be adjusted, so for welding vertical and ceiling seams, the current strength is reduced by 10-15%. It should not be forgotten that for these welding positions the electrode diameter should not exceed 4 millimeters.

If you follow these rules, the welding process will proceed steadily and the metal will not drain from the weld pool. Read more about welding techniques in various spatial positions in the article: Manual arc welding technique with coated electrodes

The welding arc voltage on the machines is set automatically, so we do not consider this parameter

The strength of the welding current is determined by the formula

Isv = πde2 * j / 4,

where de is the diameter of the electrode (electrode rod), mm;

j is the permissible current density, A/mm2.

With approximate calculations, the value of the welding current can be determined using one of the following formulas:

Iсв=k*de

Isv=k1*de1.5

Isv=de*(k2+α*de)

where de is the diameter of the electrode (electrode rod), mm;

k1, k2, α - coefficients determined experimentally:

k1=2025; k2=20; α=6.

Recommendations for choosing the current strength can be found on the pack of electrodes or in reference books and regulatory documents.

Recommended welding current values ​​for electrodes of various diameters

Source: https://svarkka.ru/%D0%BF%D0%BE%D0%B4%D0%B1%D0%BE%D1%80-%D1%81%D0%B8%D0%BB%D1% 8B-%D1%82%D0%BE%D0%BA%D0%B0-%D0%B8-%D0%B4%D0%B8%D0%B0%D0%BC%D0%B5%D1%82%D1 %80%D0%B0-%D1%8D%D0%BB%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D0%B4%D0%B0/

Types of electrodes by diameter - what they are and how to choose

There are a huge variety of electrodes on the market. They all differ in their technical characteristics and are designed for different jobs with different materials. However, the same models may differ in size and, most importantly, in diameter. Today we will find out what effect the diameter of the electrode has on its working properties and how to choose it correctly so that welding is effective and simple.

What are the diameters of the electrodes?

Different manufacturers provide different diameters. Their purpose also plays a role here. Not all metals require a large diameter, and therefore there is no need to produce rods larger than a certain size. To get acquainted with different diameters in practice, let's see what diameters different manufacturers offer in their models:

• LB 52U - 2.6, 3.2, 4, 5 mm;

• ANO-21 - 1.6, 2, 2.5, 3, 4, 5 mm;

MP-3 - 2, 2.5, 3, 4, 5 mm;

• OZS-12 - 2, 2.5, 3, 4, 5 mm;

• OK-46 - 2, 2.5, 3, 4, 5 mm;

• Uoni 13/45 - 2, 2.5, 3, 4, 5 mm.

In addition to the diameter, the length of the electrodes is also taken into account. This is not such an important parameter, but it is still useful to know about it. The length of the rod is directly dependent on the diameter. The larger the diameter, the longer the length. The reason for this ratio is the consumption of electrodes, and the frequent need to make continuous connections.

At higher currents, the electrodes melt faster.

Welders prefer to use electrodes that have the greatest length. In this case, you will not have to interrupt while working. This allows long seams to be made without interruption. The result is a beautiful, reliable and uniform connection. Long seams are not needed everywhere and short bars are great for such work.

Why aren't thin electrodes made long? The point is that they would be inconvenient to use. They would often bend and break, damaging the coating needed to perform well.

Not all brands have a wide selection of sizes, as they have their own specialization.

Dependence of diameter on metal thickness

To reliably connect large parts and massive structures, it is necessary to make a large seam on them. To obtain it, you will need electrodes with a large diameter. They can also be supplied with more current to melt metal that is thicker and requires deeper penetration.

Thus, the relationship between the diameter of the rods and the thickness of the metal is directly proportional. The thicker the metal, the larger the electrode diameter required for welding.

Some types of electrodes are available in diameters up to 8 mm. They may be required in industrial production when assembling and repairing thick structures. When welding thin-walled products, small diameters are used - from 1 mm, since this makes it possible to achieve greater weld accuracy.

If the diameter of the rod is greater than the thickness of the metal, it will simply melt through it. Melting the electrode will require power that thinner products cannot withstand.

Dependence of current on thickness of materials

Thick metal requires high temperature to melt and, accordingly, high current. An electrode with a small diameter cannot transmit a large current to the metal. Instead, it will just boil and spatter.

Thick products require high welding currents. This is due not only to the melting temperature, but also to the depth of penetration and the width of the seam. Only electrodes with large diameters can withstand high currents and efficiently transfer them to the parts being welded.

In addition to the ability to carry and use large currents, when working with thick material, the current source also plays a special role. Without a good transformer, the welder will not be able to obtain the required current values ​​​​and make a reliable connection. The device must also have a large margin of safety, since welding massive structures takes a lot of time. Not all welding equipment can operate at maximum power for several hours.

Conclusion

The choice of electrode diameter is made taking into account the upcoming work and the materials to be welded. By choosing the right electrode sizes, you can make a strong and reliable connection that will last for many years.

Electrodes with large diameters are used in special industries where structures and products operating at high temperatures, high pressure or in aggressive environments are assembled and serviced. For most household work, standard rod diameters of up to 3 - 4 mm are excellent.

Source: http://instrument-blog.ru/svarka/raznovidnosti-elektrodov-po-diametru-kakie-byvayut-i-kak-vybrat.html

How to choose electrodes for welding - Ice advice

Not all novice welders know that there are more than 200 types of electrodes for welding, of which about a hundred types are used in manual welding. They don’t need to know everything, but they need to get information about some of the most popular and frequently used ones. Therefore, let's move on to the selection of electrodes for manual arc welding.

Electrode components

An electrode is a wire coated on top with a special compound called coating.

During the welding process, the wire (core) melts under the influence of high power electric current, filling the space between the welded metal products.

The coating also melts, which releases gas during combustion. The latter envelops the welding zone, preventing oxygen from penetrating inside.

The second purpose of the coating is to protect the welded layer itself. During the melting process, part of the coating material becomes liquid and covers the weld seam. This thin film protects it from the negative effects of oxygen. Why is this protection necessary?

• During the process of melting metal, oxygen will absorb some of the energy, so the electric current may not be enough for the welding itself.
• When contacting oxygen with low humidity, oxide appears on metals, reducing its quality characteristics.

Types of coating

Currently, four types of coating are used.

The main one is marked “B”.

Sour – “A”.

Pulp - “C”.

Rutile – “R”.

There are mixed types, for example, AR - acid-rutile, RB - rutile-basic, RZh - rutile mixed with iron powder and RC - rutile-cellulose.

Most often, for manual welding with an inverter, welding electrodes with a basic or rutile coating are used. The first category includes electrodes of the UONI brand. They are usually used in cases where it is necessary to obtain a high-quality weld.

That is, the seam must meet high strength, impact strength and high ductility. At the same time, seams from the UONI welded electrode guarantee that crystalline cracks will not form inside the welded material, plus electrodes of this type are not subject to aging.

Therefore, experts recommend their use for welding critical structures that will be operated in harsh conditions.

SSSI also has its downsides. Moisture on the electrodes, rust on the end of the wire, oil or grease stains on the coating, rust on the metal products being joined - all this guarantees the appearance of cavities inside the weld seam, which reduce its quality. In addition, you can only work with these electrodes using direct current with reverse polarity.

Rutile-coated welding consumables are used primarily for joining low-carbon steel parts. Their prominent representative is the MR brand. Here are the positive characteristics of this category.

• They can operate on both direct and alternating current.
• Metal spattering is minimal.
• Using electrodes of this type, high-quality welding seams can be obtained in any position of the workpiece.
• Slag comes off easily after welding.
• Using MR, you can cook rusty products, and even heavily contaminated ones.
• Easy ignition even with a low current-voltage characteristic of the inverter.

When a beginner is faced with the question of how to choose the right electrode for welding, the best option for him is the MP brand.

Rutile coatings include ANO grades. They are used for joining carbon steel products, for example, for welding pipelines. All other characteristics are exactly the same as those of the MP.

Why do experienced welders not like to use rutile-coated electrodes? First of all, they call them sparklers. Secondly, this is soft and fast welding, and for good heating of the metal, slow welding is needed. Therefore, professionals have a negative attitude towards them, but for beginners this is just right.

Other selection options

A few more parameters that determine the choice of electrodes for welding. One of the most important indicators is the polarity of the connection, and accordingly the type of current.

If an inverter is used for welding, then you need to understand that it produces direct current. Therefore, connecting the electrode for welding can be done according to two schemes.

Polarity is straight. The diagram is as follows: minus is connected to the welding electrode, plus to ground.

The polarity is reversed. Here it’s the other way around: minus to the mass, plus to the holder.

What are the features of each connection scheme? It all depends on the strength of welding of metals. With direct polarity, the metal parts being welded are subject to high heat. With reverse polarity, the heating temperature is not so high.

Therefore, when you need to weld two metal sheets of small thickness, it is better to use reverse polarity, which will provide protection against burn-through. In addition, reverse polarity is used when welding products made from high-alloy steels.

They are sensitive to high temperatures.

There are three more indicators that you need to pay attention to.

Welding thickness

The diameter of the electrode must be related to the thickness of the parts being welded. That is, these two parameters are interconnected. Here are some ratios.

Diameter of welding material, mm Thickness of welded parts, mm 2.5 2 2.5-3 3 3.2-4 4-5 4-5 6-12 5 13

It is important to choose an electrode by diameter. The thing is that the higher this indicator, the worse the density of the seam, taking into account the ratios in the table. In addition, incorrect selection leads to instability of the welding arc, deterioration of penetration, and an increase in the width of the seam itself.

Another dependence of the diameter of the welding electrode. In this case, it depends on the current strength.

Diameter of welding material, mmWelding current, A 2 55-65 2.5 65-80 3 70-130 4 130-160 5 180-210 6 210-240

It turns out that three parameters: current strength, thickness of the metals being welded and electrode diameters are interconnected. Therefore, when answering the question of which electrodes to choose, it is necessary to take this relationship into account.

However, we note that the current strength in each category may differ slightly from those presented in the table. MR electrodes with a diameter of 2 mm can be welded at a current of 40 A. SSSI at 30 A.

Therefore, before choosing electrodes, be sure to study their characteristics, which are indicated by the manufacturer on the packaging of the welding material.

Selecting welding materials for the required metals is not always easy, because by eye you can only determine steel, stainless steel, cast iron or non-ferrous metal. It is clear that in addition to steel structures where the electrodes described above are used, in all other cases special welding products are used: for cast iron, for stainless steel, for aluminum and so on.

As for steel products, there are certain difficulties depending on the definition of the type of steel. But if you figure this out, then the question of how to choose the right electrodes will become easier to answer.

• For welding boiling-type steels, you can use any grade with any coating. These steels include: low-carbon and slightly deoxidized.
• For welding semi-quiet steels, it is better to use electrodes with rutile or basic coating.
• For welding structures made of mild steel, which are subject to high dynamic loads, and which are operated at fairly low sub-zero temperatures, it is better to use grades with a basic coating.

The quality of the weld will also be affected by the stability of the arc. Therefore, the electrode you choose must match the type of current you are using.

For welding consumables with a basic coating, only direct current is required; for other types, both direct and alternating current can be used.

For electrodes with rutile, cellulose and acid coating, which operate from welding transformers, that is, on alternating current, the arc burns stably. This means the seam is of high quality.

As for the welding direction, cellulose-coated electrodes work well in the lower and vertical positions.

Because these electrodes produce a fairly viscous slag and plus the metal of the wire is transferred to the seam in small drops, which allows you to evenly fill the joint between the metal parts.

In this regard, the worst weld seam is formed on electrodes with a basic coating.

When there is a question of welding thick-walled products, the technology determines the multilayer nature of the applied seam. Therefore, such a parameter as good slag separation becomes the main one when choosing electrodes. In this regard, electrodes with basic coating again lose out. Let us also add here that welding products of this type require a certain purity of the metals being welded.

Conclusion on the topic

Selecting a welding material according to all parameters is not easy. You will have to take into account many nuances, so it is recommended to take into account the tables located above, as well as information that indicates the purpose of the electrodes themselves.

Source: https://LEDsovet.ru/kak-vybirat-elektrody-dlia-svarki/

How to choose electrodes for welding with an inverter - Stroy-House

The ease of use of the inverter has made welding accessible to many craftsmen. This welding equipment has a control system, rectifier, filter, converter that supplies the required current.

The inverter provides direct current, the polarity of which can be changed during welding. A guarantee of a high-quality seam is the correctly selected operating mode of the unit and suitable electrodes for the inverter. There are a great variety of products.

Characteristics and sizes vary. To successfully buy electrodes for welding with an inverter, to determine which ones are best suited to each specific case, you need to delve into the essence of the process.

Principles of classification

There are several types of classifications of electrodes for inverter welding. The main feature that should be taken as a basis is the ability to melt. Rods that do not melt during welding are used to work in an atmosphere of shielding gas, such as argon.

Melting rods are used in manual arc welding with an inverter, which in practice is most often carried out at home. It is not the metal core that melts, but the coating applied on top. The components of the outer layer improve the properties of the arc and form a protective cloud over the working area.

When choosing a specific brand for an inverter, the amount of work, requirements for seam quality and advice from professionals are taken into account. You can look at specialized magazines to find out brand ratings.

But for home use, it is enough to carefully read the description on the packaging in order to understand what current and what materials the electrode is intended for welding . It is best to purchase products from a trusted supplier. To learn how to weld with an inverter, experts recommend rutile or basic brands.

Coating

When choosing electrodes for an inverter, the welding mode and the chemical composition of the consumable material are of decisive importance:

• electrodes coated with alkaline (basic) components are used if it is necessary to cook with an inverter at a constant current of reverse polarity. They are used to cook high-alloy steels;
• Rutile coatings can be used when welding with alternating and direct current of both direct and reverse polarity. Titanium dioxide (rutile) ensures easy ignition of the arc, and there is no spattering of metals during operation. This is the best option you can choose;
• for direct current (that is, an inverter), cellulose coating is suitable, which creates a good protective gas environment;
• rutile acid coating is suitable for welding metal with alternating current or an inverter (any polarity). Arc ignition occurs even at low voltage. It is important to note that when working with acidic compounds, dangerous fumes are released. Welding must be carried out with good forced ventilation.

The alloys from which the parts are made determines the type of core. The compositions must match each other.

The choice of electrodes is regulated by GOST. The standard stipulates not only the composition of the rods and coatings, but also the appearance, which excludes the presence of swelling, porous areas, and sagging.

Kernel

Electrodes for inverter welding are made from three types of materials: high-alloy wire, conventional alloy or carbon raw materials.

A novice master can navigate products by labeling. The more letters and numbers it contains, the higher the degree of doping. Each letter represents a certain additive, and the number next to it indicates its percentage.

For example, a product made of carbon steel is designated Sv-10G2, and a product made of high-alloy steel is designated Sv-30Х15Н35В3Б3Т. The difference is obvious.

Popular brands

Over the years of intensive work with inverters, a rating of the popularity of electrodes has been formed in the circles of welding specialists and home craftsmen.

The ANO brand is considered the most universal. Electrodes of this group allow you to make any welding joints: corner, butt, overlap. With this electrode product you can weld parts with a thickness of no more than 5 mm in any position, even in the vertical direction from top to bottom.

There is no need to thoroughly clean surfaces from oxidation products. These electrodes can be used for root welding of thick parts. If there is a rutile, cellulose coating, then connecting any polarity of the inverter is allowed.

The products of the MR line are presented in two categories. MP-3 works effectively with parts with varying degrees of contamination. Electrodes coated with a rutile layer are used for direct and alternating currents, for any type of inverter connection.

You need to choose a position for work, taking into account the diameter of the electrode. MP-3S products are convenient for welding in various positions. These electrodes can be used to connect parts with residual moisture.

The UUSI category is represented by electrodes for welding parts made of carbon and low-alloy steel alloys. The resulting seams are plastic, have high impact strength, and firmly connect structures for special purposes.

Electrodes coated with a base layer can be used with direct current, reverse polarity of the connection.

Electrodes marked OK 63.34 show good performance. They can weld thermally strong steels and alloys that are resistant to corrosion. It is possible to weld vertically structures of small thickness, make butt and overlap joints.

For welding structures that require high strength and reliability of the seam, electrodes of the OZS-12 brand are used. They operate on direct current of an inverter of direct polarity, as well as on alternating current.

It is also worth mentioning the brands ESAB, Lincoln, Electric, Resanta, Kobelco, which offer high quality products with rutile, basic and combined coatings. The price range here is different, and each buyer decides for himself which option is the best.

Diameter selection

When choosing a product, you should pay attention to its diameter. The thinner the design, the smaller the possible electrode diameter. For welding profiles, products with a diameter of up to 2 mm are sufficient.

By the way, you need to learn how to work with delicate products. Such electrodes quickly melt and are consumed. To work with them you must have special skills.

Depending on the diameter of the electrode, the current strength for welding with an inverter is determined. Recommended values ​​are often indicated on the top of the packaging. In general, the pattern is as follows: the larger the diameter of the electrode product, the higher the required current value.

A discrepancy between the thickness of the material, the diameter of the electrode and the current strength can deteriorate the quality of the welded joint and lead to the formation of pores in it.

Advantages

The above popularity rating was not compiled by chance, but due to the noticeable advantages of the listed products. Welding with its participation is carried out most easily by an inverter.

Difficulties in forming a weld can only arise due to the wrong choice of grade for a particular metal or alloy. When the work is carried out correctly, high-quality connections of any shape and location are formed.

Consumable electrodes of the indicated brands form slag, which, after performing its protective functions, is easily separated. There is no need to beat him for a long time and painfully. The quality of the seam will be immediately visible.

The presented types of electrodes allow you to work even with parts that have rust residues. Sometimes this feature is very important. When working in extreme conditions, there may not be time or opportunity to thoroughly clean surfaces.

Source: https://stroy-hauz.ru/kak-vybrat-elektrody-dlya-svarki-invertorom.html

Electrodes for welding: how to choose the right electrode for high-quality welding of critical elements

Gone are the days when the welding machine had a terrifying appearance, enormous size and catastrophic energy consumption. Modern welding devices are compact, easy to use and quite economical in their use of electricity.

Coupled with an affordable price, this gave impetus to their wide distribution and popularity among home craftsmen, and household welding machines, mainly based on the inverter operating principle, became reliable helpers in the home, on a summer cottage and in the garage.

To successfully carry out welding activities and obtain a result for which you will not have to blush in front of your household and friends, you need to take a serious and responsible approach to the choice of electrodes, since the quality of the weld, its reliability and durability depend on this.

Selecting Electrodes

Modern industry produces a wide range of electrodes with a wide variety of types and characteristics. Firstly, they are divided into electrodes with a melting rod or a non-melting rod.

Non-melting ones are used only in a protective gas environment (argon), therefore, in amateur conditions they are completely irrelevant. Consumable models are made from a metal central rod coated with a special layer of coating that protects the welding zone and promotes stable combustion. These types of electrodes are widely used in everyday life.

Selection by material type

The choice should begin taking into account that the electrode must be close in composition to the material of the surfaces being welded.

The following types of electrodes for welding different metals can be distinguished:

• To weld low-carbon steel, carbon types of electrodes should be selected;
• For welding nickel-plated steels, electrodes with an appropriate rod are used, for example: MP-3, ANO-21, OZS-4, UONI-13/45;
• When performing operations with high-alloy steel grades and surfacing, electrodes with high-alloy core material - TsL-11 - are used;
• The OZCh-2 grade is suitable for welding cast iron
• For copper surfaces – Komsomolets-100.

Selection by coating method

The coating covering the electrode core can be of four types:

• Rutile;
• Basic;
• Cellulose;
• Sour.

The cellulose and base coatings are intended for welding with direct current. The result of welding greatly depends on the preliminary preparation of the surfaces being processed. To work with an acidic type of coating, the room must be well ventilated to avoid damage to the welder’s health.

Rutile coating is characterized by simple ignition and low spattering. For household work, brands with rutile coating (MP-3) and basic coating (UONI 13/55) have proven themselves to be excellent.

Selection by electrode diameter

When choosing the right electrode, the thickness of the surfaces to be welded is of no small importance. As a rule, the greater the thickness of the material being welded, the larger the electrode diameter needs to be selected. The properties of the metal also matter, but this can only be determined experimentally.

The choice can be made based on the following criteria:

• For surfaces with a thickness of 2 mm. electrode diameter is 2.5 mm;
• With a thickness of 3 mm. – electrode 2.5-3 mm;
• If the thickness of the surfaces is 4-5 mm, electrodes with a diameter of 3.2 - 4 mm are suitable;
• 6-12 mm parts need to be welded with 4-5 mm electrodes;

Thicker, over 12 mm. surfaces are welded with 5 mm electrodes.

The most popular and universal size for household use is 2.5 millimeters. As a rule, this is enough for almost any household work.

Having chosen the desired diameter, you need to decide on the current strength, since these parameters are directly related to each other. Usually the manufacturer indicates the recommended amperage on the packaging.

If these recommendations are missing, you can use the following data:

Electrode diameter, mm.

2 – 2,5 – 3 – 4 – 5 – 6

Current strength, A

55-65 – 65-80 – 70-130 – 130-160 – 180-210 – 210-240

Hence the conclusion, in order to find the best electrode for welding, it is necessary to correctly determine the type of metal base, coating and diameter, and set the optimal welding current. After this, it will be possible to achieve a decent result.

popular electrodes

Based on numerous consumer reviews and recommendations from experienced professional welders, the following rating of the best electrodes was formed:

• ANO. These electrodes do not require additional calcination, light easily and give good results;
• MP-3. Electrodes can weld even poorly cleaned surfaces. Versatile.
• MP-ZS. Allows you to obtain a welding seam with improved characteristics.
• UONI-13/55. Recommended for more experienced welders. For high-quality seams and responsible design solutions.

In addition to domestic brands, electrodes from the Swedish company ESAB are widely represented on the Russian market and enjoy deserved popularity.

From the large assortment of products from this company, several of the most popular models can be identified:

• OK 46.00. In terms of its parameters, it is practically an analogue of the MP-3 brand. Used when working with unalloyed metal. The connection is of high quality.
• OK 48.00. Creates a reliable and high-quality weld.
• OK 53.70. More specialized, usually used when welding pipes.
• OK 61.30. For stainless steel.
• OK 68.81. Used when working with difficult-to-give materials.
• OK 92.60. For welding cast iron.
• OK 96.20. For welding aluminum.

These are not all articles of this brand; the assortment includes many specialized models.

Calculation of the number of electrodes

The approximate number of electrodes for the upcoming work can be determined independently, based on accumulated experience.

In addition, there are special formulas that allow you to solve this problem. Consumption is determined based on the deposited metal mass, taking into account losses (slag, splashes, cinders).

The formula for calculating the deposited metal mass is:

Weld mass = weld length*weld area*material density.

Carbon steel has a density of about 7.85 g/cm3, alloy steel - 8.5 g/cm3.

It remains to calculate the consumption of electrodes using the equation:

Consumption = deposited mass * consumption coefficient.

The consumption coefficient differs for each specific brand of electrodes used. Here are the coefficients of common brands:

• 1.5: AHO-1, OZL-E6, TsT-28;
• 1.6: AHO-5, AHO-13, SSSI 13/55;
• 1.7: OZL-9A, TsT-15, TsL-11, UONI-13/45;
• 1.8: OZS-11, OVL-20, NZH-13, K-5A,
• 1.9: ANZHR-2, OZL-27.

The data obtained will allow you to determine the approximate number of electrodes and avoid unnecessary costs.

Photos of electrodes for welding

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Source: https://mirstrojka.ru/elektrody-dlya-svarki/

Which electrodes are best to choose for welding with an inverter machine: brands, choice of diameter and current strength - Machine

Many novice welders are wondering which electrodes are best for an inverter. In this article we will answer this question and also present the most popular brands of welding electrodes used when working on an inverter machine. Recommendations on choosing electrodes for novice welders will be a bonus.

Briefly about inverters

Today there are quite a large number of inverter welding machines. Most manufacturers offer industrial and household inverters in various price categories. Industrial inverters are distinguished by greater power and increased duty cycle.

Also one of the main differences is the maximum output welding current. As a rule, professional devices have higher maximum current values.

Another difference may be the ability to connect not only to a 220 V household network, but also to a 380 Volt industrial network.

What to look for when choosing electrodes for an inverter

There are a number of parameters that must be taken into account when choosing welding materials. Let's consider the main factors in order to better understand what influences the choice of electrodes for welding with an inverter and which ones are better suited for certain jobs.

Purpose of electrodes

According to their purpose, welding electrodes are divided into several groups. This division is determined by the type of metal to be joined and its technical characteristics. The purpose of the products is also specified in GOST 9466-75.

1. Welding of carbon and low-alloy steels;
2. Welding of alloyed heat-resistant steels;
3. Welding of high-alloy steels with special properties;
4. Electric arc surfacing of surface layers with special properties;
5. Welding and surfacing of cast iron;
6. Welding and surfacing of copper and alloys.

Thus, it is better to choose an electrode for an inverter, focusing first on its purpose. This will allow you to avoid mistakes, for example, welding “stainless” steels with electrodes for “ferrous” metals.

In this case, the weld metal will be susceptible to corrosion. Select consumables based on the type of metal being joined and its characteristics.

After which you can determine the required type of consumable (for example, for low-alloy steels it can be E46 or E50A).

When the purpose of the electrode is determined, you can proceed to selecting a specific brand that matches the characteristics, and also select the diameter of the product.

Coverage type

There are several types of coating for welding electrodes, the most popular of which are rutile and basic. These types of coatings have fundamental differences that manifest themselves during their application.

Basic coating

Products with a basic coating have a number of advantages. They provide a high-quality seam that is resistant to intergranular corrosion and alternating loads. Allows the execution of work and operation of the finished structure in low temperature conditions.

However, their successful use requires certain skills. Also, such products must be calcined before use. And the metal to be connected must be cleaned of dirt and rust.

Such electrodes operate only on direct current of reverse polarity.

Rutile coating

Products with this type of coating are quite versatile and are suitable for beginners in inverter welding. They provide a high-quality connection when welding even on oxidized or contaminated metal. However, if possible, it is better to clean the welding area.

These consumables operate on both direct and alternating current. Due to the composition of the coating, they are quite easily re-ignited, and relatively little slag is formed during operation. In this case, slag separation does not require significant mechanical action.

The choice of coating type is based on the requirements for the welded joint. These may include tensile strength, yield strength, impact strength and others. The requirements outlined above may be influenced by the type of metal being welded, its chemical composition and other characteristics.

Electrode diameter

The choice of diameter depends on the thickness of the metal being welded. For greater clarity, this relationship is shown in the table below.

Steel thickness (mm)	1,5-2,0	3,0	4,0-5,0	6,0-12,0	>13
Electrode diameter (mm)	2	2,5-3	3-4	4-5	5-6

For joining metals less than 1.5 mm thick, manual arc welding with an inverter is, as a rule, not used. It should also be taken into account that the setting of the welding current depends on the thickness of the steel and the diameter of the electrode, as well as on the spatial position of the weld. So if you plan to weld thick metal, take an inverter with high maximum current values.

Current setting
Electrode diameter (mm)	2	2,5	3	4	5	6
Current (A)	40-64	65-80	70-130	130-160	180-210	200-350

Popular brands of electrodes for inverter welding

There are several most common and popular brands of electrodes used in inverter welding.

Popular electrodes with rutile coating type E46

The most common electrodes from this group are the following brands: GOODEL-OK46, MP-3, MP-3S, OZS-12 and ANO-21.

Despite the fact that these brands belong to the same group and have similar characteristics, they have a number of features that determine their use. For example, MP-3 digests rust better, and ANO-21 is used primarily for ceiling seams.

Otherwise, these consumables are interchangeable. These electrodes are most convenient for novice welders to work with.

Popular electrodes with basic coating type E50A

In this group, popular products include the brands UONI-13/55, GOODEL-OK48, as well as LB-52 and its high-quality analogue GOODEL-52U. Just like the materials from the previous group, they have a number of differences.

UONI-13/55 is more often used for joining structural steels in the construction of bridges and critical structures. GOODEL-OK48 is preferable to use when working with thick sheet metal. And GOODEL-52U are professional electrodes for welding oil pipeline pipes and pipe elements.

All these brands have high technical characteristics and resistance to low temperatures.

Electrodes for welding stainless steel with an inverter

To connect high-alloy steels (stainless steel), the following grades are used: NZh-13, OZL-8, OZL-6, TsL-11, TsT-15, EA-400/10, EA-395/9. Here the choice should be based on the characteristics and chemical composition of the metal being welded.

Electrodes for welding cast iron

To work with cast iron, you can use products of the following brands: MNCh-2, OZCh-2, TsCh-4. At the same time, MNCh-2 are used for welding, surfacing and welding defects in cast iron parts made of gray, malleable and high-strength cast iron. TsCh-4 for cold welding of structures made of high-strength cast iron with nodular graphite and gray cast iron with flake graphite. And OZCh-2 for joining and surfacing gray and ductile cast iron and welding defects in cast iron.

Electrodes for copper welding

To work with copper, consumables of the following brands are used: Komsomolets-100 and OZB-2M. At the same time, Komsomolets-100 products are intended for welding and surfacing of technical grade copper products, as well as dissimilar copper-steel compounds. And OZB-2M for welding and surfacing of tin-phosphorus and artistic bronzes, surfacing on steel and bronze and for welding defects in bronze casting, as well as brass.

Cutting electrodes

Products of the OZR-1 brand are well suited for cutting sheet metal and reinforcement. They are suitable for removing defective areas of welds, or sections thereof, tacks, rivets and much more. It should be taken into account that cutting is performed at increased current values ​​ranging from 260 to 680 Amperes, depending on the diameter of the electrode and the thickness of the metal.

What affects the quality of welding with an inverter

We have already told you which electrodes are best for welding with an inverter and are ready to move on to the factors that influence the quality of the weld.

1. Welder skills and experience. This is the determining factor. An experienced and competent welder can always perform high-quality welding in compliance with all technologies. Please note that we wrote “skills and experience”, since there are types of industries in which welders perform monotonous work. For example, a welder who performs only horizontal welds in production will most likely not be able to perform high-quality vertical welds from top to bottom. In no case do we want to offend welders, but such cases have occurred in practice. It’s not for nothing that there is a special certification of welders at NAKS, the passage of which gives access to certain types of work.
2. Quality of materials. This is the second determining factor. Electrodes for welding with an inverter must be of high quality. They must also be stored correctly and calcined before use according to the recommendations indicated on the packaging.
3. Equipment quality. The inverter must be of high quality, capable of providing stable operation. A common problem with low-quality equipment is voltage surges, the inability to stabilize the arc, and sticking of the electrode.

We have listed three main factors that affect the quality of a welded joint. This also includes the correct selection of the diameter of the product, its brand, setting the current strength, the conditions under which the work is carried out, and much more.

Which electrodes are best for the RESANTA inverter

Quite often, novice welders ask the question which electrodes are better for the RESANTA 220 or RESANTA 190 inverter. This question is due to the popularity of welding equipment from this manufacturer.

The company's official website contains research data from the Russian Association of Trading Companies and Manufacturers of Power Tools for 2014-2017.

, according to which in 2017 the share of RESANTA welding inverters on the Russian market was 51%.

Recommendations for novice welders

As promised at the beginning of the article, we will give some recommendations for novice welders.

1. It is better to start practicing with rutile electrodes. Due to the composition of the coating, they are easier to work with. Such consumables have easier ignition (including re-ignition), and also allow you to cook on a medium arc. This in turn makes it possible to better see and control the weld pool. Another advantage of such products is the easy separation of slag.
2. Correctly set polarity and current strength are the key to success. If it is necessary to carry out work on direct current of straight polarity, then the workpiece to be welded is connected to the “+” terminal, and the electrode to the “–”. Accordingly, with reverse polarity, the connection is made the other way around: the workpiece is connected to the “–” terminal, and the holder to the “+”. It is better to set the current strength within the limits specified by the manufacturer, adjusting it during the welding process.
3. Before you start working, you should practice on scraps that have similar characteristics to the metal of the workpiece. This will allow you to adjust the current strength and get used to the metal.
4. Compliance with safety precautions is an important condition for welding work. Do not start welding without protecting yourself and others from possible burns, electric shocks and “hares”. Use protective clothing and gloves, as well as a special mask or goggles. Make sure the welding machine is connected correctly. Keep flammable objects away from the welding area. Also, do not allow strangers (without special protection) or animals (they may get eye burns from looking at the welding arc) into the work area.
5. Improve your skills regularly. Learn new materials, try different welding positions and consumables. Take advanced training courses. Practice and the results will follow.

Welding electrode sizes

You can currently find many types of electrodes on the market, which differ in the materials used for their manufacture and their sizes. Such welding rods for joining metals can be produced in various sizes. When choosing certain varieties of such surfacing materials, it is necessary to take into account their diameter, length, basic composition and type of coating. We will tell you in more detail how to choose the right length and diameter of the electrodes used.

Choosing the right diameter

The diameter of the rods, along with the composition of their alloy, is one of the most important parameters, therefore, when choosing one or another variety, you need to correctly determine the size you need, which will be the key to high-quality welding work. The thickness of the rod directly depends on the size of the base material.

So, for example, if you need to weld metal sheets several millimeters thick, then you should choose electrodes that are small in size.

If you are connecting metal parts with a thickness of several centimeters, and the depth of the seam will approach ten millimeters, then it is necessary to appropriately use thick surfacing rods for this work, which will ensure the strength of the connection.

This characteristic is also influenced by the power indicator of the welding transformer. Different metals can differ significantly in their melting point; accordingly, it is necessary to correctly select the sizes of the surfacing materials used.

With the right choice, the melting temperature of the base surfacing material will be the same, which will allow both the electrodes and the base material to melt simultaneously . Consequently, the connecting seam will be uniform, high quality and durable. At the same time, you must understand that powerful transformers at high operating currents can instantly melt electrodes whose diameter is 2-3 millimeters.

If the diameter is chosen incorrectly, this can lead to a significant deterioration in the quality of the connection. If melting requires high power and high temperature, this can lead to the appearance of through holes in thin metal sheets. That is why it is necessary to correlate the thickness of the surfacing rods used with the characteristics of the base metals and their sizes.

Selecting the length of the electrodes

The length of the electrodes is not such a significant parameter for welding, however, in certain situations, the wrong choice can lead to a significant deterioration in the quality of the welding work performed. The length of the electrode depends on its thickness and the characteristics of the elements being welded.

It is necessary to understand that during the welding process, any interruption in the temperature treatment of the joint invariably leads to significant deterioration of the weld..

Therefore, it will be necessary to select sizes of surfacing materials that will minimize or completely eliminate such welding interruptions, which will improve the quality of the work performed.

Short electrodes can be used in cases where long seams are not required. In this case, rods of 10 centimeters will be sufficient.

But if you need to weld parts 30 centimeters or more in size, you need to choose electrodes that are appropriate in size, which will allow you to complete this work without interrupting welding. Please note that you should not purchase excessively long electrodes if you need to make short connections.

In this case, if the length of the rods is chosen incorrectly, there is a risk of their breaking, which in turn leads to shedding of the coating, and without it the quality of the connection deteriorates significantly.

Currently, electrodes of various sizes can be found on sale. These can be either standard rods 10-15 centimeters long, or special varieties 30-40 centimeters or more long. It must be remembered that not all brands of electrodes are manufactured with a full range of sizes, which leads to some difficulties when choosing such a surfacing material.

Diameter and length of common varieties

1. LB-52U. The manufacturer produces these brands with a diameter of 2.6 to 5 millimeters and a length of up to 35-40 centimeters.
2. ANO-21. The length can be a maximum of 0.25-0.4 meters, with a diameter of 1.6-5 millimeters.
3. MP3. This is a common type of surfacing rod and is available in a wide range.

   The diameter ranges from 2 to 5 millimeters, while their length reaches 45 centimeters.

4. ANO-6. Buyers are offered three standard sizes, ranging from 3 to 5 millimeters. For electrodes with a diameter of 3 millimeters, the maximum length can be 35 centimeters.

   A five-millimeter surfacing rod has a maximum length of 45 centimeters.

Correct selection of electrodes

The diameter of the electrodes used for welding must be selected taking into account the thickness of the workpieces. In this case, the composition of the surfacing and base material should be as similar as possible, which will allow for a uniform, strong connection. It is also necessary to take into account the melting temperature of the parts being connected, which must be the same.

In the event that metal products with a thickness of 1-3 millimeters are welded, then two-millimeter electrodes and an operating current of the inverter from 25 to 100 Amperes can be used. If you are welding parts with a thickness of 3 to 6 millimeters, then electrodes with a thickness of 3-4 millimeters can be used. The optimal operating current is 150-200 Amperes.

Welding surfacing materials with a diameter of more than six millimeters can be used to weld metal with a thickness of 10 centimeters or more.

Important. Before starting welding, you should evaluate the condition of the coating, which should not be damaged, which can significantly deteriorate the quality of the weld.

The length of the electrode is important in cases where it is undesirable to interrupt the welding process, which can lead to a deterioration in the quality of the work performed.

For example, when repairing sealed containers for high-pressure pipelines, interrupting the welding process and using several rods to weld one joint can lead to a significant decrease in reliability. As a result, expensive and complex repairs will be required in the future.

There are also certain metal alloys for which interruption of welding will invariably lead to deterioration in the quality of the joint. That is why, when choosing the length, it is necessary to proceed from the length of the weld and select the rods in such a way that their size is larger than the weld.

By choosing the right welding rods, taking into account their length and thickness, you can ensure a high-quality connection, while the resulting seam will have the necessary decorative effect, mechanical strength, durability and corrosion protection.

Source: https://svarkagid.com/razmery-jelektrodov-dlja-svarki/

How to choose the diameter of the electrode for welding?

When the task is to buy electrodes, of course, it is better to understand this issue thoroughly: what types of metal are there, how they differ, what metals they are intended for, as well as what types and brands of electrodes there are.

Now, in order to start practicing making seams as quickly as possible, a simpler choice will be considered.

As for choosing a store, it is preferable to buy in a specialized store that sells welding equipment and consumables, rather than in a regular hardware store, because in a specialized store, most likely, the sellers understand this topic and will be able to suggest something.

Where everything is sold, most likely, the sellers do not have proper competence in the selection of welding electrodes.
In addition, it often happens that prices are higher in regular hardware stores. Perhaps it is implied that a person who buys such materials in a non-specialized store does not understand the issue enough to have a good idea of ​​how much they cost.

Arriving at a specialized store, it is enough to say that you need electrodes for welding carbon steel of ordinary quality, or ordinary carbon steel.
Each type of electrode can have several brands. For example, Table 5 with electrodes of type E46 is shown.

Type	Brand
E46	MP3C; ANO-21, ANO-4; OZS-4, OZS-6, OZS-12, etc.

Sometimes the marking is marked with the letter “A” - for example, E46A.
This means increased ductility of the weld. Since type E46 is taken as an example, further explanation of the principles of selection will take place using the example of the same type of electrodes. There is a wide range of electrodes of the ANO brand (21, 36, 4, etc.), OZS, MR-3.

It is unlikely that the store will have the entire “line” of a certain label. Most likely there will be one or two options. It makes sense to buy the smallest portion that they can offer and try which electrodes will produce the highest quality seams in this particular situation.

It also makes sense to try welding with UONI 13/55 electrodes, this is type E50. It differs from the E46 type; in some situations, with their help it will be possible to obtain a better weld.

In any case, you first need to try: buy a small batch, and then, if you get a high-quality result, you can take the required quantity for the entire volume of welding work.

Working principle of the electrode

The figure shows a diagram of the manual arc welding (MAW) process.

An electrode is a metal rod on which a coating or coating is applied.

As a result of the burning of the arc 3 and under the influence of its temperature, the metal rod 5 melts, and the metal from this rod is transferred to the weld pool 2. The coating also melts due to the high temperature. As a result of its melting, they form protective gases that protect the arc and weld pool from the effects of oxygen, nitrogen and other gases contained in the air. In addition, the resulting gases help stabilize the arc.

During the melting of the coating, liquid slag is formed, which spreads over the surface of the weld pool. At the same time, liquid slag deoxidizes the metal, ridding the weld pool of oxygen, and, conversely, adds alloying additives to improve the quality of the weld metal and the welded joint as a whole. As the weld cools, the liquid slag turns into a slag crust 10, which must subsequently be removed.

recommendation on how to choose an electrode

This video contains recommendations for novice welders.
Let's consider these questions:

• What electrode diameter is suitable for a particular metal thickness;
• What welding current to set to obtain a high-quality seam.
• Difference between welding modes: direct polarity and reverse polarity

Electrode diameters

Measured in millimeters, these values ​​are standard and according to Russian GOST they are: 1.6; 2; 2.5; 3; 4; 5; 6, etc. Imported ones also have other diameters, for example 2.6 instead of 2.5; 3.2 instead of 3.

Diameters larger than 4 mm are not of interest for household welding work, because the household electrical network does not produce such power that would allow the use of electrodes with a diameter of 5-6 mm or more.

Even with a diameter of 4 mm it is often impossible to use, since welding machines, as a rule, do not produce the required welding current, and some electrical networks, especially outside the city, do not allow welding with such electrodes.

The diameter of the electrode, indicated in millimeters, means the diameter of the metal rod, that is, without taking into account the thickness of the coating. Typically, the larger it is, the longer it is.

Defects

The coating must be applied to the electrode evenly along the entire length and circumference. If the coating is uneven in thickness, that is, it is thicker in some places and thinner in others, this is a defect. When the coating is applied evenly along the length, but is thicker on one side and thinner on the other, this is also a defect. In such cases, it is more difficult to obtain a high-quality seam.

The coating should not crumble or fall off. If the coating has fallen off at the end of the electrode, lighting the arc will be much more difficult. In addition to cases of manufacturing defects, the coating can also crumble when the electrode is old or has not been stored properly. One way or another, working with such a rod will be very difficult, or even impossible.

Popular: Electrodes for cast iron - there is a brand for each type of work

Electrode ends

In this embodiment, the metal rod is covered with slag, and when trying to strike an arc, there will be no electrical contact between the metal rod and the metal of the part, and the arc will not burn. It is necessary to hit the hard dielectric surface hard enough to dislodge the slag.

The electrode coating is covered with slag

If metal is visible at the end of the electrode, then igniting the arc will not cause problems. In the photo below the situation is the opposite. The coating fell off. In this case, it will be difficult to ignite the electrode for another reason.

The coating performs the function of protecting the arc, stabilizing the burning of the arc - roughly speaking, “helps the arc burn.” If there is no coating, the arc will either not burn at all, or will burn very unstable, and good welding will not work. The problem is solved by biting off this part of the electrode.

The electrode coating has fallen off

There is another option for more experienced welders - to “strike” the electrode, barely touching the metal and preventing the electrode from sticking to the part. To do this, you need to apply minimal force in the vertical direction and sufficient force in the direction of movement of the electrode parallel to the part, without holding the electrode in one place. Perform the required number of movements in this way until the metal rod burns.

Remaining electrode

When making a weld, the electrode burns out and the question arises to what minimum length to use it. In other words, how long should the cinder remain.

In principle, the optimal length is 3 cm, but this figure may vary. For example, if there are 4 cm left and you need to make the next relatively long seam, then there is no point in burning out this centimeter. It's better to get a new one right away.

It is undesirable to burn the rod up to the holder, since in this case the electrode holder itself will deteriorate. In addition, when making a weld with a short electrode length, the weld pool is blocked by the holder, and it becomes impossible to visually control the progress of the seam.

When welding thin metal, that is, 0.5-1 mm thick, the depth of the weld pool is greater than the thickness of the metal. Therefore, if you simply weld such metal without preparing the edges, it will be burned through. To prevent this from happening, flanges are made when welding two parts end-to-end.

When the flanged edge melts from the heat of the arc, the bent parts melt inward, close the entire gap between the workpieces and, together with the metal that comes from the electrode, form a seam. Thus, the metal does not melt through, but a completely filled seam is obtained. (Experienced and highly qualified welders are able to weld such thin metal without flanges, but amateur welders, as a rule, do not succeed.)

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Welding electrodes for an inverter: how to choose - Metalworker's Guide

• Date: 09-06-2015
• 728
• : 42

Correctly selected electrodes for the inverter are one of the conditions for obtaining a high-quality welding seam that is correct in all respects. The modern market offers a large selection of electrodes for welding with an inverter. They differ in type, diameter, coating material and other characteristics. Check out the features of the available options and choose the one that suits you best.

Welding inverter circuit.

Existing types of electrodes for inverter welding

First of all, you need to select the appropriate type of products for welding with an inverter. They are usually divided into melting and non-melting. The consumable type of product for welding with an inverter is a wire rod with an external coating.

This coating contributes to a more stable burning of the welding arc and provides good gas-slag protection of the metal being processed. Electrodes that are designed to work with steels of indefinite composition, copper, stainless steel and other materials are made from a special alloy.

Non-consumable variations are used primarily in argon welding.

Selecting the appropriate electrode diameter for inverter welding

Table of types of electrodes.

The electrodes have different diameters. Their length may also vary. Depending on the alloying characteristics of the steel rod, the products used for welding with an inverter can have a length of 30-45 cm.

Electrodes of almost every existing diameter have found wide application. Except for variations with a diameter of 1.6 mm. They are supplied exclusively to order and are practically never used by Russian craftsmen.

Features of the classification of welding electrodes

The most commonly used classification of products is based on their purpose. In accordance with this parameter, products are divided into:

1. Electrodes for working with low-alloy and carbon steels.
2. For working with heat-resistant, high-strength steels.
3. For working with high-alloy steels, they are also “stainless steel electrodes”.
4. For working with aluminum and various alloys based on it.
5. For cooking copper and various alloys based on it.
6. For working with cast iron and its alloys.
7. For repair work and surfacing.
8. For working with difficult-to-weld and steels of uncertain composition.

In addition, these devices are classified according to the type of coating they have. There are 4 types of coverage in total, but 2 of them are the most popular.

Basic electrodes allow you to weld seams of the best quality.

Type 1 is the main electrodes. They got this name because... have a basic coating. The most popular among such products is the UONI 13/55 model.

It allows you to obtain seams of excellent quality, with high impact strength, mechanical strength and ductility. The resulting seams are resistant to crystallization cracks and are not very prone to aging.

As a rule, they are used when working with various critical structures, for cooking products that will be used in harsh conditions.

Among the disadvantages of products of this type, we can highlight the fact that moistening the coating, lengthening the arc, the appearance of rust, oil or scale on the edges of the welded parts leads to the appearance of pores. In addition, they can be operated exclusively on constant reverse current. Type 2 includes products with rutile coating. They are used primarily for working with mild steel products. The most popular representative of the category is MP-3.

Such products are characterized by high technological parameters, namely:

1. The arc remains stable in both direct and alternating current.
2. There is minimal spattering of material.
3. They allow you to create high-quality seams in any spatial position.
4. Excellent slag separation is noted.
5. Can be used for welding rusty and contaminated surfaces.
6. The resulting welds have a good appearance.

Rutile electrodes are suitable for welding mild steel.

You need to know what polarity and type of current you need to work with. Most inverter models produce direct current. When working on direct current, the workpiece and electrodes can be connected in 2 ways, namely:

1. If the polarity is straight, then the working electrode should be connected to the “minus”, and the workpiece to the “plus”.
2. If the polarity is straight, then the electrode is connected to the “plus”, and the part to the “minus”.

When operating on the positive pole, there is a higher heat production when compared to this value when operating on the negative pole. Therefore, the use of reverse polarity will be justified in the following situations:

1. When welding thin sheet metals. A smaller amount of heat will protect the workpiece from burning through.
2. When welding high-alloy steels. Return flow reduces the likelihood of overheating.

Direct polarity is best used for welding massive parts. There are 3 very important characteristics related to each other, namely:

1. Welding current.
2. Product diameter.
3. Thickness of working materials.

First you need to understand the relationship between the diameter of the working electrodes and the thickness of the materials being processed. Thus, steel up to 1.5 mm thick is in most cases welded semi-automatically or argon welding is used. Arc, as a rule, is not used. Focus on the following values:

Electrode welding diagram.

1. For steel with a thickness of 2 mm, products with a diameter of about 2.5 mm are suitable.
2. To work with steel 3 mm thick, you need to use variations of 2.5-3 mm.
3. Steel with a thickness of 4-5 mm will require electrodes with a diameter of 3.2-4 mm.
4. When working with material 6-12 mm thick, you need to use 4-5 mm products.
5. If the steel is thicker than 13 mm, you need to use electrodes 5 mm thick.

It is imperative to take into account the fact that increasing the diameter of the electrode for welding with an inverter helps to reduce the operating current density. Because of this, the arc begins to oscillate, wander and change length.

As a result, the penetration depth decreases and the seam width increases. As a rule, manufacturers of such devices provide information about the required welding current sizes directly on the packaging of their products.

If the manufacturer has not provided such information, use the following values:

1. When using an electrode with a diameter of 2 mm, the current will be 55-65 A.
2. If the product has a diameter of 2.5 mm, then a welding current of 65-80 A is needed.
3. Electrodes with a diameter of 3 mm operate at a current of 70-130 A.
4. A product with a diameter of 4 mm will require a current of 130-160 A.
5. If the diameter of the product is 5 mm, the current should be 180-210 A.
6. For a 6 mm product, a current of 210-240 A will be required.

Thus, when choosing the diameter of the electrode for welding with an inverter, you must pay special attention to the thickness of the material being processed. If you weld thin metal with electrodes that are too large in diameter or exceed the required welding current, porosity may appear in the weld metal.

How to understand the marking of imported electrodes?

Types of markings of welding electrodes.

The most common among foreign-made electrodes are ESAB brand products. The name of each of them begins with the letter combination OK, followed by a 4-digit numeric designation. There are quite a few variations, but the highest quality and most widely used are the following varieties:

1. OK 46.00. The properties of this product are similar to variations under the brand name MP-3. Suitable for working with low alloy and carbon steels. Can be used on direct and alternating current. Provides high-quality welding seam.
2. OK 48.00. Designed to work with particularly critical structures. Used on direct current.
3. OK 53.70. Used for welding root passes and pipe joints. They belong to the category of specialized products.
4. OK 61.30 and OK 63.20. Used for welding stainless steel of various grades. Before purchasing, be sure to check with the seller whether this type is suitable for working with your specific stainless steel.
5. OK 68.81 are excellent models. Suitable for working with difficult-to-weld materials and steels of unknown composition.
6. OK 92.60. Designed specifically for cast iron and its welding to steel.
7. OK 96.20. Will come in handy for those who have to work with aluminum.

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How to choose suitable electrodes?

Thus, after analyzing the above information, we can identify a number of main criteria that you need to pay attention to when choosing electrodes for welding with an inverter. First, you need to decide what metals will be processed. Choose them according to the type of metal.

If important welding will be performed, it is better to buy quality products from a reputable manufacturer. For example, the Swedish products mentioned above have proven themselves to be excellent. Secondly, if you have to weld carbon steel, you need to pay attention to the cleanliness of the surface of the material being processed.

If it is wet and covered with rust, then for welding you need to use products with a rutile coating.

To work with critical structures, it is recommended to use electrodes with a basic coating.

In such situations, you must remember that such products require mandatory preparation of the surface to be treated. Thirdly, you need to decide on the thickness of the working material, select the appropriate welding current and diameter of the product. Approach the selection process as responsibly as possible. If you choose the optimal electrodes, then even using an inexpensive inverter you will be able to weld almost any metal at the highest level.

Source: https://ssk2121.com/svarochnye-elektrody-dlya-invertora-kak-vybrat/