How are welding electrodes made?

Welding parts using various types of electrodes

Arc welding has long been used mainly in the repair of cast iron parts. The reason for this was the low mechanical properties of the directed metal, since welding was carried out with a bare electrode.

The molten metal, not protected from exposure to atmospheric air, was saturated with oxygen and nitrogen.

With an increase in oxygen content, all mechanical properties of the directed metal decreased. With increasing nitrogen content, the strength characteristics increased, and the plastic properties decreased.

The decrease in plastic properties is explained by the aging of the deposited metal, which occurs due to different solubilities of oxygen and nitrogen in steel at different temperatures.

In the deposited metal when welding with a bare electrode, the oxygen content is 0.221% and nitrogen 0.110%. Welded joints with such a high content of oxygen and nitrogen and such low plastic properties could not find application even in low-critical structures.

The second significant disadvantage of bare electrode welding was the need to use direct current, since it was impossible to ensure a stable arc with alternating current. Welding with direct current also required the use of more complex and expensive welding machines than welding transformers.

Welding parts with electrodes with thin (ionizing) coatings

To obtain a stable arc, 40-45 years ago it was proposed to apply a thin coating layer to the electrode rod, consisting of elements with a low ionization potential, as a result of which the ionization of the arc increased.

Usually chalk diluted in liquid glass was used.

The coatings made it possible to significantly increase the stability of the arc, as a result of which welding with alternating current became possible.

The coating is applied in a thin layer with a thickness of 0.15 to 0.55 mm per side, depending on the diameter of the electrode wire, which is why they are also called thin coatings.

Thin ionizing agents do not reduce the oxygen and nitrogen content in the deposited metal and do not significantly increase its mechanical properties. This is explained by the fact that they do not provide slag protection for the molten metal. The main purpose of ionizing coatings is to increase the stability of arc combustion.

For ionizing coatings, salts and oxides of alkali and alkaline earth metals are used, since they have the lowest ionization potential. The most common of them are chalk, potash, granite, titanium dioxide, feldspar and so on.

The advent of electrodes with ionizing coatings made it possible to use arc welding in building structures bearing static loads, as well as when welding thin sheet metal.

When welding parts made of thin metal with a thickness of less than 2.0 mm, low current strengths are required - 20 - 60 A. The stability of the arc at low current strength is reduced, so electrodes with special coatings are used that ensure maximum ionization of the arc.

Welding parts with electrodes with thick (high-quality) coatings

Welding of the most critical structures subject to dynamic loads with electrodes with ionizing coatings could not be used due to the low mechanical properties of the welds; Therefore, the scientific thought of welders worked on the problem of creating new coatings and new welding methods that would ensure alloying of the deposited metal.

As a result of the work carried out, new electrode coatings were developed that provide the necessary protection of the metal and significantly increase the mechanical properties of welds. These coatings were applied to the electrode rod with a layer of 0.5 - 1.6 mm per side and were called high-quality or thick coatings.

When developing these coatings, the welding process was considered as a metallurgical process, but occurring in a short period of time.

The laws of metallurgy were used to study the welding process. As is known, in metallurgy, slag protection is used to protect molten metal from exposure to air, deoxidizers are used to reduce the oxygen content in the molten metal, and alloying elements are introduced to increase mechanical properties.

Despite the fact that the metal during welding is in a molten state for a short time, it turned out to be possible to influence the chemical composition of the deposited metal by introducing certain components into the coating.

Along with slag protection, work was carried out to protect the molten metal with a shell of reducing or neutral gas. As a result, gas-forming coatings, gas-electric, atomic-hydrogen, argon-arc and other welding methods appeared.

Source: http://electro-shema.ru/svarka/svarka-detalej-razlichnymi-tipami-elektrodov.html

Homemade electrodes for welding

The main consumables for manual arc welding are welding electrodes. Every master must have them, otherwise there will simply be nothing to cook with.

This product probably cannot be called scarce - today the choice of these materials is huge, there are products for joining different metals. The cost of some types varies within reasonable limits due to high competition in the market.

You can make a welding electrode with your own hands for experimental purposes, or in extreme conditions. You need to understand that manufacturing will require various raw materials, which may not be available on the farm.

Consumables

To make homemade electrodes we will need:

• binder in the form of liquid glass;
• limestone or chalk;
• low carbon wire of suitable diameter;
• roller or brush.

“Liquid glass,” with its scary name, is a fairly common product and is sold in almost every hardware store.

Manufacturing process - step-by-step instructions

So, we have decided on the materials and can start making electrodes with our own hands.

1. First of all, we need to grind the chalk to a powder. This can be done using a heavy metal object, but it is better to use a blender. So the particles will have a uniform structure and have a fine fraction.

2. We take steel wire and cut it into rods. You can use the factory dimensions as a guide and make rods 250 mm long.

3. The next step is to coat the steel rods with liquid glass.

4. Carefully distribute the crushed chalk on a flat surface. Roll out a steel rod coated in liquid glass over this surface, evenly distributing chalk particles over the body of the steel workpiece.

5. We wait until the electrode dries, check that the liquid glass has crystallized and put it in the oven at 100 °C for half an hour.

The welding characteristics of such an electrode will be low, it will produce a lot of sparks, be difficult to burn and stick. But by selecting the correct welding modes and the necessary preparation of the welded surface, you can achieve good results. Share your techniques for making electrodes or other welding materials.

Source: https://svarkagid.ru/sdelaj-sam/oborudovanie/svarochnye-elektrody-svoimi-rukami.html

Electrodes for welding - types, markings and selection

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.

1. The main one is marked “B”.
2. Sour – “A”.
3. Pulp - “C”.
4. 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.

Attention! Experts do not recommend using MP for welding vertical seams from top to bottom.

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.

1. Polarity is straight. The diagram is as follows: minus is connected to the welding electrode, plus to ground.
2. 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 are welded well in the lower position and vertically. 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://svarkalegko.com/materials/vidy-svarochnih-elektrodov-i-ih-vibor.html

How to cook using electric welding

In a private house, in a country house, in a garage and even in an apartment - everywhere there are many jobs that require metal welding. This need is especially acute during the construction process. Here, especially often, something needs to be cooked or cut off.

And if you can still cut it with a grinder, then there is nothing to reliably connect the metal parts with except welding. And if the construction is carried out with your own hands, then the welding work can be done independently. Especially in places where the beauty of the seam is not required.

We will tell you how to properly weld by welding in this article.

Basics of electric welding

Welded metal joints are the most reliable today: pieces or parts are fused into a single whole. This happens as a result of exposure to high temperatures. Most modern welding machines use an electric arc to melt metal. It heats the metal in the affected area to the melting temperature, and this happens over a small area. Since an electric arc is used, welding is called electric arc welding.

This is not a completely correct way of welding)) At a minimum, you need a mask

Types of electric welding

An electric arc can be formed by both direct and alternating current. Welding transformers use alternating current, and inverters use direct current.

Working with a transformer is more complicated: the current is alternating, so the welding arc “jumps”, the device itself is heavy and bulky. The noise that both the arc and the transformer itself makes during operation is also quite annoying. There is one more problem: the transformer greatly “stresses” the network. Moreover, significant voltage surges are observed. The neighbors are not very happy about this fact, and your household appliances may suffer.

Inverters mainly operate from a 220 V network. At the same time, they are small in size and weight (about 3-8 kilograms), operate quietly, and have almost no effect on voltage.

The neighbors won't even know you started using the welding machine unless they see you. In addition, since the arc is caused by direct current, it does not jump and is easier to stir and control.

So if you decide to learn how to weld metal, start with a welding inverter. Read about choosing an inverter welding machine here.  

Welding technology

For an electric arc to occur, two conductive elements with opposite charges are required. One is a metal part, and the second is an electrode.

The electrodes used for manual arc welding consist of a metal core coated with a special protective compound. There are also graphite and carbon non-metallic welding electrodes, but they are used for special work and are unlikely to be useful to a novice welder.

When an electrode and metal of opposite polarity touch, an electric arc occurs. After its appearance, in the place where it is directed, the metal of the part begins to melt. At the same time, the metal of the electrode rod melts, being transferred with the electric arc to the melting zone: the weld pool.

How a weld pool is formed. Without understanding this process, you will not understand how to weld metal correctly (To enlarge the size of the picture, right-click on it)

During the process, the protective coating also burns, partially melting, partially evaporating and releasing a certain amount of hot gases. Gases surround the weld pool, protecting the metal from interaction with oxygen. Their composition depends on the type of protective coating. The molten slag also coats the metal, also helping to maintain its temperature. To weld properly, you must ensure that the slag covers the weld pool.

The weld is formed by moving the bath. And it moves when the electrode moves. This is the whole secret of welding: you need to move the electrode at a certain speed. It is also important, depending on the required type of connection, to correctly select its angle of inclination and current parameters.

As the metal cools, a slag crust forms on it - the result of the combustion of protective gases. It also protects the metal from contact with oxygen in the air. After cooling, it is beaten with a hammer. In this case, hot fragments fly away, so eye protection is required (wear special glasses).

You can read about how to make a barbecue out of a cylinder or barrel here. Just get some practice.

How to learn to cook by welding

It all starts with preparing the workplace. Safety when working with electric welding must be given increased attention: there is a possibility of injury from both electricity and high temperatures. Therefore, take your preparation seriously.

It is more convenient to learn to weld with electric welding on a thick piece of metal: it is better to practice on it. In addition to it and the welding machine, you will need gaiters (thick gloves) and a welder’s mask. You also need thick clothing that protects the entire body, and durable shoes with thick leather. They must withstand sparks and scale. You will also need a hammer and a wire brush to knock off the slag. You will need glasses to protect your eyes.

How to connect the electrode

It will be easier for beginners to carry out welding work if they take a universal electrode with a diameter of 3 mm (3.2 mm, to be precise). They are more expensive, but easier to work with. After you learn how to weld metal, you can try using cheaper ones, but it’s better to start with these.

The electrode is inserted into a holder attached to one of the welding cables. There are two types of clamps - spring and screw. If the electrode holder is spring-loaded, press the button on the handle and insert the electrode into the socket that appears. When screw clamped, the handle rotates. Unscrew it, insert the electrode and clamp it. In any case, it should not wobble. After installing the electrode, you can connect the cables.

There are two outputs on a DC welder: positive and negative. There are also two welding cables:

• one ends with a metal clamp-retainer - it is connected to the part;
• the other is a holder for the electrode.

Which polarity to connect for welding depends on the type of work. If we talk about inverters, then more often the plus is connected to the part, and the minus is supplied to the electrode. This connection option is called direct polarity. But there is a list of works in which reverse polarity is applied: minus to the part, plus to the electrode (for example, for welding stainless steel).

Direct and reverse polarity of connection on the welding inverter

Straight polarity provides better heating of the metal, which is necessary for most connections. This is explained by the fact that electrons move from the negatively charged pole - with straight polarity, this is the electrode - to the positive - part. At the same time, they additionally transfer their energy to the metal, increasing its temperature.

Start of welding: light the arc

We figured out how to connect the electrode to the inverter. Now about how to light an arc. It occurs when there is direct contact between the electrode and the part. There are two ways:

• chirping;
• tapping.

Everything is clear from the name: in one case, you need to run the electrode along the seam (so that there are no marks left), in the second, you need to hit the part with the tip of the electrode several times.

When the electrode is new, its tip is exposed, ignition occurs easily. If it was already in use, a wall of several millimeters of protective coating would form around the rod. This coating needs to be knocked off by hitting the part with the tip several times.

Both methods of ignition are used, here everyone chooses what is convenient for them. This skill is the first one you will have to master if you want to learn how to use electric welding.

Therefore, you take several electrodes, a thick piece of metal, and try to strike an arc. Once you have succeeded, you can proceed to the next stage of training.

Electrode tilt

The main position of the electrode is tilted slightly towards you - at an angle from 30° to 60° (see figure). The amount of inclination is selected depending on the required weld and the set current. Focus on the condition of the weld pool.

The first position is called the “backward angle.” In this case, the bath and molten slag moves behind the tip of the electrode. Its angle of inclination and speed of movement must be such that the slag has time to cover the molten metal. In this position, we obtain heating of the metal to a greater depth.

Manual arc welding technique: positioning the electrode at an angle forward and at an angle backward

There are situations when the metal does not need to be heated very much. Then the angle of inclination changes to the opposite, the seam and the bathtub “stretch” behind the electrode. In this case, the heating depth is minimal.

Electrode movements

The answer to the question “how to properly weld with electric welding” is simple: you need to control the weld pool. To do this, it is necessary to hold the electrode at a distance of 2-3 mm from the metal surface and control the condition and size of the weld pool. This is where the skill of a welder lies.

The difficulty lies in the fact that several parameters have to be controlled simultaneously:

• move the electrode along one of the trajectories shown in the photo,
• as it burns, lower it a little lower, maintaining a constant distance of 2-3 mm;
• monitor the size and condition of the weld pool, accelerating or slowing down the movement of the electrode;
• follow the direction of the seam.

The movements of the electrode tip are shown in the figure. Those who want to learn electric welding for home use do not need to master all of them, but you will need two or three movements: for different situations, seams and metals.

Another element of manual arc welding technique: the tip of the electrode must move along one of these trajectories (or something similar)

How to learn to cook with electric welding? Practice movements on a thick piece of metal. Then you get not seams, but rollers. This stage is the initial one. On it you will master the basic skills of a welder: learn to control the distance from the tip of the electrode to the part, and at the same time, move it along a given path, monitor the weld pool and the slag in it.

To do this, take thick metal and draw a line on it with chalk: you will need to lay a roller along it. You light the arc and begin to master the movements, learning to control the bath at the same time. You won’t succeed the first time, or even the tenth time. You will probably use a dozen electrodes. When the manual arc welding technique has been mastered: the bead is uniform, its width and height are constant (or almost), you can try to connect the parts.

You should get similar rollers. This way you can learn how to weld using electrodes correctly.

Read how to make a gazebo on a metal frame in this article, and here the construction of a shed on a metal frame is described.

How to weld metal correctly

Learning to hold the electrode correctly and move the bath is not enough for a good result. It is necessary to know some of the subtleties of the behavior of the metals being joined. The peculiarity is that the seam “pulls” the parts, which can cause them to warp. As a result, the shape of the product may differ greatly from what was intended.

Electric welding technology: before starting to apply a seam, the parts are connected using tack welds - short seams located at a distance of 80-250 mm from each other

Therefore, before work, parts are secured with clamps, ties and other devices. In addition, tacks are made - short transverse seams laid every few tens of centimeters. They hold the parts together, giving the product its shape. When welding joints, they are applied on both sides: this way the resulting stresses are compensated. Only after these preparatory measures do welding begin.

Read about the types of welds and joints (horizontal, vertical, ceiling) and how to weld them correctly here.

How to choose a current for welding

It is impossible to learn how to weld using electric welding if you do not know what current to set. It depends on the thickness of the parts being welded and the electrodes used. Their dependence is presented in the table.

But with manual arc welding, everything is interconnected. For example, the voltage in the network has dropped. The inverter simply cannot produce the required current. But even under these conditions you can work: you can move the electrode more slowly, achieving good heating. If this does not help, change the type of movement of the electrode - passing over one place several times. Another way is to use a thinner electrode. By combining all these methods you can achieve a good weld even in such conditions.

Now you know how to weld properly. All that remains is to practice the skills. Choose a welding machine, buy electrodes and a welding helmet and start practicing.

To reinforce the information, watch the video lesson on welding.

Source: https://stroychik.ru/tools/kak-pravilno-varit-svarkoj

What are welding electrodes made of?

A rod made of metal or other materials, coated with a special coating, electrically conductive and designed to supply current to the surfaces being processed during the process of joining metal is called an electrode.

Electrodes are an integral element of metal connection

It was first used during an experiment aimed at studying the properties of an electric arc in 1802 by the famous Russian scientist Petrov.

Active improvements to this important welding element, which led to the creation of arc welding, began in the early 1900s. Modern electrodes for welding are produced in more than two hundred brands. They differ in materials, sizes and scope of use. The electrode, as they say, is the hot heart of welding: it melts quickly, tightly connects

Types of electrodes for welding work

More than half of all electrodes are produced directly for electric arc welding.

Depending on the category, they are rods made from gauge welded wire by cold stretching, coated with certain substances by crimping under high pressure, or carbon or tungsten rods with additives.

The protective coating performs the functions of ensuring high arc performance, protecting the weld pool from the harmful effects of air components and its metallurgical processing. A connection using such electrodes is arc welding with coated electrodes.

Wire for consumable electrodes

Electrode wire, from which electrodes for electric arc welding are produced, is divided into three groups according to its chemical composition.

• Carbon (up to 0.12%). Used to join medium carbon steel and low carbon steel.
• Alloyed. Used to join alloy steel.
• Highly alloyed. For joining high-alloy steel with special properties.

Each type of welding has its own electrode

Coatings

Welding electrodes have a protective layer, which consists of a mixture of substances that together give the electrode the necessary properties.

• Stabilizing effect. They regulate arc combustion due to the introduction of alkaline earth and alkali metals (calcium, sodium, potassium).
• Formation of a slag film around the bath. The mixture consists of manganese and titanium ores and minerals: silica, fluorspar, granite, etc.
• Release of protective gases. A combination of inorganic (magnesite, marble, etc.) and organic (wood flour, starch, etc.) substances.
• Filling. Alloying components and deoxidizers (manganese, titanium, silicon, etc.) or their alloys with iron. They are responsible for the composition of the metal at the junction. Aluminum (deoxidizer) is added in powder form.
• Recovery of metals from oxides obtained during melting. Ferrotitanium, ferromanganese and ferrosilicon act as deoxidizers.
• Bundle of all fillers. “Liquid glass” is an aqueous dispersion of potassium and sodium silicates that provides the necessary integrity of the protective layer.
• Plasticization. Molding additives that improve the quality of the seam (dextrin, kaolin, bentonite, etc.).

  Welding electrodes types of designation

Based on the type of coating, electrodes have the following classification.

• A (A) – acidic coating.
• B (B) – main coating.
• C (C) – cellulose coating.
• P (R) – rutile coating.
• RB, RA, RC (RB, RA, RC) – mixed coating.
• P – other coatings.
• F – iron powder is introduced into the coating, which increases productivity. If the electrode contains more than 20% powder, the abbreviation includes the letter Z.

Welding technology depends on the classification of electrodes, type of welding and scope of application. Uncoated electrodes are used as filler material for gas shielded welding.

The process of connecting parts

Electrode categories

Arc welding electrodes come in two categories, which are based on the role of the electrode in the welding process.

• Non-consumable electrode for electric arc welding. Performs the function of an arc exciter without directly including its material in the composition of the melt in the weld pool. It is usually made from tungsten with additives of oxides of certain metals (yttrium, cerium, lanthanum, zirconium, etc.), synthetic graphite and electrical coal. Additives help maintain optimal arc parameters and increase current density. Graphite electrodes have higher electrical conductivity and resistance to oxidation during operation than carbon electrodes.
• Consumable electrode for electric arc welding. At the same time it acts as a filler material. During the melting process, it is mixed with the main components of the melt, protecting the weld pool from the negative influence of atmospheric impurities and alloying the seam. Characteristic technology for manual arc welding.

Selection and application of electrodes

The technology of work and the area of ​​use depend on the specific welding characteristics of the types of electrodes.

• C – optimal for connecting large diameter pipes. The seam is made in a ring, thanks to the purpose of the electrodes for vertical seams, located from top to bottom. Used in the organization of pipelines.
• P - optimal for top layers and fillet welds, tack welds, due to the easy secondary excitation of the arc and the appearance of the joint.
• RC – suitable for working in a wide variety of spatial positions. Provides a thick coating suitable for installation work.
• RB – connection of root layers when laying pipelines of medium and small diameter.
• B – work in all spatial positions. The resistance to cracking of the seams and the increased viscosity of the resulting melt make them indispensable when welding thick-walled parts and materials with limited joining ability or subsequent operation in harsh conditions (negative temperatures). The low hydrogen content makes it possible to reliably join high-strength steels.

Depending on the material being welded, welding electrodes are used that have a set of properties that are optimal in a particular case.

• For high-alloy steel and alloys, electrodes with a high melting rate are used. This is possible due to their low thermal conductivity and high resistance.
• To join carbon and low-alloy structural steels, electrodes are used that provide certain properties of the weld: impact strength, tensile strength, bending angle, elongation. Classification – R, A, B, C, RA, RB, RC.
• Surfacing is carried out using special electrodes for surfacing surface layers, which have special properties through manual arc welding.
• Welding and surfacing of cast iron is performed with electrodes capable of eliminating casting defects.
• Non-ferrous metals are welded with electrodes for electric arc welding, which have a high melting point, thermal conductivity and protective properties.

  Technology for heating concrete in winter using electrodes

An electrode correctly selected, taking into account all indicators and characteristics, will ensure the best quality of seams and decorative effect, which is important when welding non-ferrous metals due to subsequent use.

Source: https://rem-serv.com/iz-chego-delayut-elektrody-dlya-svarki/

Do-it-yourself welding electrodes - how to do it right?

Do-it-yourself welding electrodes - how to do it right?

Today, electrodes on store shelves come in a huge variety. Therefore, it is very difficult to call them a scarce and rare commodity.

However, for general information and for fun, you can try to make homemade electrodes, so to speak, at home. In the process of making electrodes with your own hands, you can understand how and what the welding coating consists of, what the main manufacturing material is, the electrode rod.

What to make welding electrodes with your own hands

The main materials in the manufacture of welding electrodes are the following components:

• Low carbon wire of small diameter;
• Liquid glass;
• Chalk comes in powder form, but limestone can also be used.

So, as is already becoming clear, the rod of homemade electrodes will be made of steel wire. Its diameter should be small, within 2-3 mm. In the process of making electrodes with your own hands, the wire will have to be cut into pieces, the length of which should be approximately 25 cm.

The coating for homemade electrodes will be made of liquid glass and chalk. The last component, chalk, if it is in pieces, will have to be thoroughly crushed to a powdery state. You can read more about how to make electrodes with your own hands below, in this article on the site about manual arc welding mmasvarka.ru.

The process of making homemade electrodes

First of all, you need to prepare the wire for the electrodes. It should be made of low-carbon steel and cut into 25 cm rods. Then you will need to grind the chalk into powder. In this case, the powder particles should be as small and uniform as possible.

It is not necessary to mix chalk with liquid glass in the process of making electrode coating. It will be enough to take a brush and coat the steel rods with liquid glass. Then it will be necessary to dip the electrodes into the chalk several times, distributing it evenly over the surface of the wire.

However, this is not the end of making electrodes with your own hands. After the homemade coating dries on the wire, and usually this happens quite quickly, the electrodes will need to be calcined. The electrodes are calcined in an electric oven for about half an hour at a temperature of 100 degrees.

Of course, do-it-yourself electrodes made in this way will not have high performance. Most likely, when used, homemade electrodes will stick to the metal or, worse, burn poorly.

However, by experimenting with the settings of the welding machine, you can still achieve good results. Have you ever used homemade wire electrodes?

Source: https://mmasvarka.ru/elektrody-svoimi-rukami.html

What does a welding electrode consist of - types of coatings, markings, classification

To create conditions for stable arc burning, as well as to give the weld the required properties, a special coating of welding electrodes is used, which is a powdery material that coats the product. The quality of such coating directly determines the efficiency of the welding performed and the strength of the welded structures.

Covered Welding Electrodes

Properties of electrode coating components

In order for the seam to come out of good quality, special components are needed. So, when performing welding work, in the welding zone it is necessary to ensure the creation of the most suitable conditions for quick and reliable connection of metal surfaces. Let us list the main tasks performed by electrodes with special coating.

Arc discharge stabilization

In order for the welded arc to have maximum stability, the electrodes are coated with special substances that have a low ionization potential. This leads to the fact that when performing welding work, the arc is saturated with free ions, which stabilize the combustion process. Today, electrode coating may include components such as potash, sodium or potassium liquid glass, chalk, titanium concentrate, barium carbonate, etc. These coatings are called ionizing.

Protecting the welding area from atmospheric gases

The components that make up the electrode coating contribute to the creation of a protective cloud consisting of carbon dioxide and carbon monoxide, and also participate in the formation of the slag layer that forms on the weld and shelters the weld pool from gases contained in the surrounding air. Gas-forming components include dextrin, cellulose, starch, food flour and others. And slag is formed by kaolin, marble, chalk, quartz sand, titanium concentrate, etc.

Electrode coating components and their properties

In addition to protecting the weld from gases contained in the air, slag helps to reduce the cooling rate of the metal and its subsequent crystallization, which in turn has a beneficial effect on the release of gases and unnecessary impurities from the metal being welded.

Weld metal alloying

Alloying helps to improve a number of properties of the weld. The main metals that contribute to alloying are titanium, manganese, silicon and chromium.

Melt deoxidation

During welding, it is very important to remove oxygen from the metal, for which special deoxidizers are used - these are substances that react with oxygen more efficiently than iron and bind it. These are titanium, molybdenum, aluminum or chromium added as ferroalloys to the electrode coating.

Tying all the constituent elements together

Coated electrodes require a strong connection between the coating and the rod, as well as all the constituent elements of the coating among themselves. In this case, the main binding component is sodium silicate or liquid potassium glass. It is worth recalling that liquid glass (essentially silicate glue) also perfectly stabilizes the welding arc, which makes it an indispensable component of all types of electrodes.

Features of coatings

The composition and thickness of the coatings used has a direct impact on such indicators as the stability of the electric arc, the viscosity of the molten metal, as well as slag, the behavior of the metal during the transition to the weld pool, etc.

Chemical composition of the coating

The following types of coatings are distinguished depending on the components included in its composition.

Rutile

They are based on the mineral rutile, which makes up the main part of the coating; the remaining components are silica, magnesium or calcium carbonate, ferromanganese. Electrodes with rutile coating are distinguished by the fact that the transition of metal into the weld pool occurs with minimal spattering.

The seam is smooth and characterized by easy separation of scale, which contributes to the high quality of the work performed. Rutile electrodes also provide easy arc re-ignition, making the welding process faster.

Another advantage of this coating is that it is safer for the health of the welder.

Rutile electrodes are not only of pure type, but also of mixed type: rutile-basic, rutile-cellulose, rutile-acid. The entire set of electrodes with rutile coatings allows you to work with almost any type of seam.

Covered electrode welding diagram

Pulp

The main feature of this type of coating is the creation of a large volume of gases and a small percentage of slag during the welding process, which is very convenient when welding vertical seams.

Cellulose-coated electrodes can include organic resins, talc, cellulose itself and various ferroalloys.

The only drawback of this coating is the low ductility of the weld metal, which is caused by the large volume of hydrogen released during the combustion of organic matter, as well as increased spattering of the metal.

Basic

The composition of such electrodes includes magnesium and calcium carbonates, which are most often marble, dolomite and magnesite. It is best to carry out welding work on such electrodes with direct current, since with alternating current, fluorspar added to such electrodes (to dilute the slag) can deteriorate the quality of the weld. But with a small amount of fluorspar in the coating composition, it is quite possible to work with alternating current.

Electrodes with a basic coating are used when welding critical steel structures, since the metal of the resulting weld has high ductility. Features when working with such electrodes include the fact that the seams are quite rough and convex. They must be stored in a dry place, because electrodes of this type are highly hygroscopic.

With iron powder

The introduction of iron powder into the coating significantly increases labor productivity. The penetrating power of the arc increases, which has a positive effect on the quality of welding of joints with increased or uneven gaps, and also facilitates re-ignition of the arc.

Acid coatings

These electrodes are coated with oxides of iron and manganese, which release a significant amount of oxygen into the welding arc. This reduces surface tension, giving the metal greater ductility, thereby increasing its temperature and making the molten metal more fluid. This has a beneficial effect on the speed of work, but increases the risk of undercuts.

Manganese also forms dangerous oxides that negatively affect the health of the welder, so recently such coatings have been replaced with rutile acid.

When choosing welding electrodes, you must take into account the composition of their coating, the type of which is indicated in the marking.

Welding electrode diagram

Electrode coating thickness

GOST 9466-75 regulates the division of electrodes into several types according to thickness, based on the ratio of the outer diameter of the electrode D to the diameter of the rod d.

• thin (D/d < 1.2 – (“M”));
• average (1.2 < D/d < 1.45 – (“C”));
• thick (1.45 < D/d < 1.8 – (“D”));
• especially thick (D/d > 1.8 – (“G”)).

Electrode marking

There are dozens of modifications of types and brands of electrodes, so for successful orientation in their varieties, universal marking was introduced. Of course, by the marking of the electrode you can always understand what kind of coating it has. The main parameters in this case are the thickness and type of coating. In addition, the marking mentions the permissible spatial position of the weld, as well as the type of current.

An example of deciphering the markings of a coated electrode

For example, consider electrode E46.

• 1 – indicates the thickness of the coating (D is thick);
• 2 - means the type of coating (P is rutile);
• 3 - indicates the permissible position of the seam (1 - suitable for all positions);
• 4 is the type of current (1 means alternating and direct current of any polarity).

Effect of humidity on electrodes

The water contained in wet electrodes (namely, the hydrogen included in its composition) has an extremely negative effect on the quality of welded joints, promoting the formation of cracks and impairing the stability of the arc. To remove excess moisture before starting work, it is recommended to calcinate the electrodes, which significantly increases the stability of the electric arc and has a beneficial effect on the quality of the seams. For welding particularly important structures, it is necessary to use electrodes with a reduced hydrogen content.

Marking of welding electrodes

Production of coatings for electrodes

When producing welding electrodes, it is necessary not only to accurately observe the quantitative content of all necessary components, but also to ensure their uniform distribution along the entire length of the coating. To do this, precision equipment is used that qualitatively grinds the substances used, sifts them through a system of sieves, forms a coating composition in the required consistency and applies it to the rod.

After mixing the dry components, liquid glass is added to them, which acts as a binding element that facilitates the effective transformation of raw materials into a single mass. The resulting paste is applied to the electrodes using the crimping method, after which they enter special chambers for drying and then for calcination.

A competent choice of electrodes for welding will help even the least experienced welder to ensure the proper quality of welding work, and will also save time and money.

Source: http://met-all.org/obrabotka/svarka/iz-chego-sostoit-elektrod.html

Do-it-yourself homemade electrodes for aluminum - Metalworker's Handbook

Are you interested in what aluminum electrodes exist for electric arc welding and shielding gases? Let's talk about industrial and homemade rods!

What electrodes are used to weld aluminum?

Melt coated rods:

• OZANA-1 and OZANA-2;
• OZA-1 - OZA-2;
• UANA;
• Capilla ALU 60/12 Si;
• Aluminil Si 12;
• EAL 4047;
• ALUMIN-351N;
• ZELLER 480;
• OZR - OZR-2 is best used for cutting metal.

1) OZANA-1, OZA-1, ESAB 96.10 are used for surfacing and welding of pure aluminum alloys with preheating of the metal. The process occurs on a direct current of reverse polarity. The seam is corrosion resistant.

2) OZANA-2, OZA-2, ESAB 96.50 weld silicon alloys (silumin), AL4, AL9, AL11, suitable for casting. Direct current of reverse polarity. The rods need to be calcined, and the metal needs to be heated.

3) UANA (salt coating) for aluminum casting alloys AD00, AD0, AD1, AD, AMts.

UANA operating modes

4) Capilla ALU 60/12 Si special coating for joining aluminum-silicon alloys (Al-Si, Al-Mg-Si, Al-Si-Mg-Cu). Price 2,350 rubles per 2 kg package, rod diameter 2.5 mm.

Capilla ALU 60/12 Si

5) Electrodes for aluminum Aluminil Si 12 with a special white coating for joining parts where color matching is required. They repair pipes, windows, furniture, and car parts. Cast alloys with a Si content of up to 12% - AlSi 12 (Cu), AlSi 10 Mg (Cu), AlSi 6 Cu 4. Metal thicker than 15 mm is heated before welding from 150 °C to 250 °C.

Characteristics of Aluminil Si 12

6) EAL 4047 for joining aluminum alloys:

• Al Si 12 (aluminium-silicon);
• Al Si 12 (Cu);
• Al Si 10 Mg (aluminium-magnesium-silicon);
• Al Si 10 Mg (Cu);
• Al Si 6 Cu 4.

EAL 4047

7) ALUMIN-351N for the restoration of turbines, drifts, covers, pistons, pipes with a thickness of more than 2 mm. Weldable materials:

• Al Si 5 Mg (3.2341);
• Al Si 10 Mg (3.2381);
• Al Si 10 Mg (Cu) (3.2381);
• Al Si 12 (3.2581);
• Al Si 12 (Cu) (3.2583);
• Al Si 11;
• Al Si 9 Mg;
• Al Si 9 Cu 3;
• Al Si 7 Mg;
• Al Si 6 Cu 4.

ALUMIN-351N

ZELLER 480 with improved coating for electric arc welding and surfacing of aluminum, silumin, duralumin. Used to eliminate casting defects and repair engine blocks, crankcases, etc.

9) OZR-1 and OZR-2 for cutting at high speeds with the rod tilted in the opposite direction. The electrode movements are reciprocating: top-down or forward-backward. Calcination of products for 1 hour, at a temperature of 170 degrees.

Aluminum electrodes quickly absorb moisture; it is better to store them in dry places.

Tungsten electrodes for aluminum welding (non-consumable):

• WP with green tip;
• WZ-8 with white markings;
• WL-15 (golden color);
• WL-20 (blue marking),

grades and sharpening of tungsten electrodes and welding of aluminum with argon.

For semi-automatic machines, wire MAL 4047, ER 4043, ER 5183, ER 5356 is used.

The price for the rods described above is decent and homemade “kulibins” make homemade electrodes for aluminum welding. At home, making rods with your own hands is not difficult. The recipe is simple:

• take aluminum wire 3-4 mm, cut into pieces 300-350 mm, sand;
• grind the chalk, combine with liquid glass (silicate glue), mix to a paste;
• Apply the mixture to the prepared pieces with a layer of 2 mm and dry.

The wire is immersed vertically in the coating solution, leaving a clean end 30 mm long. Homemade rods are hung to dry.

How to weld aluminum with an electrode

Aluminum alloys have different weldability due to the presence of alloying elements of different concentrations in them. The table will help you identify easy and difficult to weld groups of materials.

When the metal thickness is more than 5 mm, welding of aluminum with an electrode is performed with cutting of the edges. The V-shaped groove is made with a bevel of 45-60 degrees, and the technological gap between the workpieces is 1-2.5 mm, based on the thickness of the elements being welded.

Products subjected to welding need to be dried (insurance against weld porosity), and the electrodes need to be calcined according to the manufacturer’s instructions.

The prepared edges are degreased with acetone or solvent.

Electric welding of aluminum with an electrode is performed at a right angle (without tilting the rod), with a short arc.

For thick metal, the joint is heated to a temperature of 150-200 degrees.

The technology is performed by an inverter using direct current of reverse polarity (positive pole on the electrode, negative on the part).

Required welding accessories:

• power source for manual arc welding;
• metal brush for cleaning the oxide film;
• hammer for removing slag crust;
• welding brush;
• electrodes;
• leggings.

If anyone does not have any of the equipment described, then hurry to the store to buy it.

Process description

Let's take, for example, a material with a thickness of 10 mm. We cut the edges at an angle of 45 degrees. Use a gas burner to dry and heat the edges of the parts, having previously degreased them.

We heat the product with gas to 200 degrees

Using clamping devices, install the plates with a gap of 1 mm and remove the oxide film with a brush.

An abrasive tool cannot be used; abrasive particles will enter the viscous layer of the aluminum alloy and cause weld defects.

After stripping, we perform welding with a dry electrode with a diameter of 3 mm. After each pass, remove the slag with a hammer. Slag connections are not allowed.

If the technological recommendations are followed, a strong connection is obtained.

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Source: https://ssk2121.com/samodelnye-elektrody-po-alyuminiyu-svoimi-rukami/

DIY electrodes for welding aluminum

Aluminum electrodes for welding are metal rods coated with coating. The coating protects the metal from oxidation and improves the quality of the weld. They are practically not used in large workshops and factories, since their efficiency is not enough to perform large volumes of work. But such electrodes are widely used by home craftsmen.

A carbon electrode is often used to weld aluminum. In this article we will tell you everything you need to know about aluminum rods and explain in detail how to make your own welding electrodes.

Features of welding aluminum at home

Anyone who has welded aluminum at least once in their life knows that this is a very difficult task. There is an oxide film on the surface of the metal, which makes the welding process difficult. Do-it-yourself aluminum welding electrodes can solve this problem.

But before you start, you need to thoroughly clean the surface. Remove contaminants and carry out comprehensive preparation of the metal for welding. This will improve the quality of the seams and they will last longer.

For high-quality welding of aluminum parts, you need a welding machine that produces direct current and is connected in reverse polarity. If you are using electrodes for aluminum arc welding, then pay attention to the current strength. This parameter should be set to a small value.

Follow our recommendations to get the job done efficiently:

• If you need to weld thick parts, then the approximate location of the seam must be properly heated before welding. This is done using a regular gas burner.
• Be sure to clean the seam of slag and pour boiling water over it.
• Once the grout has cooled, clean it again using a stiff brush. Do not disregard this advice, as remaining slag can promote corrosion.

Popular brands of electrodes

As we mentioned earlier, a carbon electrode is often used to weld aluminum. But besides this, there are a number of brands that are no less popular among beginners and experienced welders. So, what electrodes can you use for welding aluminum with your own hands?

OK brand rods

These electrodes are manufactured by ESAB and are marked OK. We recommend using models 96.10, 96.20 and 96.50. Yes, they are not universal, but with their help you can weld technical aluminum or manganese-based aluminum alloys. These aluminum electrodes for welding at home have shown themselves to be on the positive side, but keep in mind that they require special care and strict adherence to the expiration date.

Rods brand OZA

In principle, such electrodes for welding aluminum with your own hands can be made, since they are based on simple aluminum wire. These rods are used for welding pure aluminum or its silicon alloys.

UANA brand rods

These are very highly directional rods used for welding cast aluminum alloys. They are practically not used in home welding, but we could not include them in our list.

EHF brand rods

EHF are tungsten electrodes; they must be used when welding with argon. It is difficult to make such electrodes for aluminum with your own hands, but if you have the opportunity to purchase them, be sure to try them in your work. Yes, with their help it is difficult to strike the arc correctly, and professionals often do not recommend such electrodes. But if you learn to hold an arc with such rods, then you will not have problems with all the others.

Manufacturing instructions

It doesn't matter what brand of electrodes you need to purchase, in any case it is not cheap.

Especially for beginner welders. We have found a solution to this problem and suggest you make the rods yourself. There are many videos on the Internet in which experienced craftsmen explain the technology for making materials for welding. We also decided to share our instructions on how to make homemade electrodes with your own hands. Follow these simple steps:

• Prepare aluminum wire with a diameter of no more than 4 millimeters and cut it into rods 20-25 centimeters long. These parameters are usually sufficient, but you can change the diameter and length as you wish. Our base is ready.
• Now let's prepare the coating. Grind up chalk (preferably regular white) and mix it with silicate glue (sometimes called “liquid glass” in stores). Mix everything thoroughly until smooth and dip the aluminum rods into it.
• Make sure that the coating layer does not exceed 2 millimeters. Leave the electrodes to dry. When the coating hardens, the rod can be used for work.

Yes, such electrodes for resistance welding are inferior in quality to factory products, but they still allow you to perform simple work that does not require increased responsibility and a perfect seam. This instruction may seem too simple, but believe me, electrodes for spot welding on your own can also be effective and will absolutely save your money.

Please note that this is not a factory carbon electrode or zinc electrode, it is not European quality. So test your electrodes first before working on unwanted metal.

Instead of a conclusion

Now you know how to make welding electrodes with your own hands and what features you should consider before getting started. Be sure to try homemade rods and share your experience in the comments, it will be useful for other welders. Also share this article on your social networks. Good luck!

Source: https://svarkaed.ru/rashodnye-materialy/elektrody/elektrody-dlya-svarki-alyuminiya-svoimi-rukami.html

Electrodes for welding. Types and device. Application and operation

Welding electrodes are rods of metal or other material that, when passed by a powerful electric current, melt or melt the surface of the workpiece, resulting in the creation of a connecting weld. Electrodes are divided into grades depending on the type of work they are used for. Currently there are more than 200 brands.

All types of welding electrodes are divided into two groups:

• Metal.
• Non-metallic.

Non-metallic

Made from coal or graphite. They do not melt and effectively transmit electricity, while heating up, but the surface they touch heats up the most. As a result, the metal melts, acquiring fluidity, and fills the seam. A physical process of diffusion is created, which ensures the mixing of molecules from the two workpieces, resulting in a reliable connection.

Metal

Such welding electrodes are also non-consumable and consumable .

Non-consumable metal electrodes come in four types:

• Tungsten.
• Thoriated.
• Lanthanated.
• Iterated.

The consumable subtype of metal electrodes is available in 2 forms:

The coated ones have a special coating on the rod, which, when heated, releases a gas that prevents oxidation of the fluid metal. Their rod is made of identical metal to the workpiece that is welded. It can be steel, cast iron, aluminum, copper, bronze and so on. An aluminum electrode cannot weld steel, just like a cast iron electrode cannot weld copper. Compliance of materials must be 100%.

Bare electrodes are long wires that are used in a semi-automatic welding machine. This equipment feeds the wire along with the gas flow, so it is surrounded by a favorable environment that prevents oxidation during melting. For welding ferrous metals, carbon dioxide is usually supplied.

The presence of more than 200 grades of electrodes is due to the fact that there are many varieties of steels with a special structure.

In order for the molten electrode rod to effectively fix the parts being connected, it must be in full compliance with the material with which contact is made. If you use a rod of a different structure, the connection becomes unreliable.

When enough pressure is applied, the seam comes off. This is especially noticeable when welding cast iron. If you use conventional electrodes for steel, then when melting they simply do not attach to the parts.

There are grades of electrodes for each type of steel. It can be any metal - heat-resistant, alloyed, structural, low-alloy, stainless and other types of steel.

Covered electrodes for arc welding

Electric arc electrodes are the most popular because they are used for the most common type of welding equipment. They are used in production and at home. Almost all metal structures in construction are welded with such equipment. Inverter and other types of welding machines that work with similar electrodes are sold on store shelves.

These welding electrodes are a type of metal melting rods with a protective coating. Their core is made of the metal that needs to be welded. The device itself of such electrodes consists of a metal rod made in the form of a long rod, the coating of which goes along almost the entire perimeter, except for a small tail.

An uncoated tail is used for fixation in the welding machine holder, since the coating does not conduct current and its presence will not allow contact to be created. The working part of the electrode is the end, which is also uncoated.

When it touches the part that needs to be welded, the joint heats up and the electrode begins to melt, and its coating releases a gas that prevents oxidation.

Electrodes for arc welding differ from each other not only in the metal of the core, but also in its diameter in millimeters. The thinner the rod, the faster it melts. If you need to weld a workpiece that has a thick body, then you need to choose a large diameter electrode. It is worth noting that the possibility of application depends on the classification of the welding machine. Using electrodes with a large diameter creates a high load, which can cause weak equipment to burn out.

To ensure reliable welding using such electrodes, it is important that not only the melting rod, but also the workpiece is heated. This ensures reliable mixing of liquid metal at the molecular level. If a thin rod is used for thick workpieces, the surface will remain cold while the electrode is already flowing. As a result, after cooling, such a connection can be broken off with bare hands. If you use a thick electrode on a thin-walled sheet metal, then the surface to be welded will simply burn through and the weld will not be formed. Thus, electrodes for welding are selected individually

It is worth noting that such electrodes have a limited shelf life, since over time the coating loses its properties and cannot, when melted, create a gas cloud that prevents oxidation. Coated welding electrodes should be stored in a dry place. If they come into contact with excess moisture, the coating will become damp. As a result, performance deterioration is observed.

When the rod is heated, the moisture in the coating quickly evaporates, resulting in rapid expansion. As a result, during welding with wet electrodes, small drops of molten metal begin to fly off to the sides, which is unsafe. Besides this, there can be no question of any reliable and beautiful seam. If the electrodes are not very wet, they can be dried by placing them in a warm place or in the sun.

Sometimes, even after drying, they cannot completely resume their former characteristics.

The use of such electrodes allows for a very reliable welding connection, but there are also certain disadvantages.

First of all, this is due to the need to periodically remove the tails from the burnt electrodes from the holder and insert fresh rods. Depending on welding skills, this is done once every 1-2 minutes.

The thickness of the inner core also affects the frequency of replacement. The tail removed from the holder is always hot, so it only needs to be removed with pliers.

Welding wire for semi-automatic machines

Wire electrodes for welding are thin wire wound on a spool. Its weight can be 0.5, 1 or 2 kg. Sometimes even larger spools are sold, but they are not suitable for all welding machines.

The wire is used for welding with semi-automatic and automatic equipment. Often it does not have any coating other than a polymer that prevents corrosion. Sometimes bronze, copper or aluminum is applied to the surface of the welding wire to prevent rust.

The layer of non-ferrous metals is very thin, so it does not in any way affect the efficiency of welding work.

A semi-automatic welding machine feeds the wire through the sleeve along with a flow of carbon dioxide. Upon contact with the surface being treated, the tip of the wire heats up and melts. Due to the fact that carbon dioxide pushes out all the air at this time, oxidation does not occur. If you turn off the gas supply, the molten metal begins to boil, resulting in a porous seam, and the wire itself constantly burns out.

Relatively recently, the production of welding wire with flux began. It has a fine powder coating similar to coating electrodes for arc welding. This range is more expensive, but has its advantages. It can be used on classic semi-automatic welding, which usually works with carbon dioxide, but without its supply. The use of such wire eliminates the need to refill cylinders and transport them along with the semiautomatic device.

The operating principle of non-consumable electrodes and their scope of application

Non-consumable welding electrodes are used in cases where it is necessary to solder two or more workpieces by melting their own metal. Typically graphite rods are used for this. Such electrodes are often used to ensure a reliable connection of twisted electrical cables.

To do this, you need to touch the twist, after which the surface of the metal at the junction will begin to instantly heat up. As a result, copper or aluminum will quickly melt and the created drops from different veins will fuse with each other. In the future, electric current will pass through the soldering area without the risk of oxidation and loss of contact.

This is much more reliable than conventional twisting or even the use of specialized terminals.

Unlike conventional consumable electrodes, non-consumable electrodes can hardly be called consumables. The fact is that after work they remain almost the same as originally. Only minor loss of length occurs.

Thus, the use of such electrodes is more profitable from an economic point of view. Typically, such rods are used to connect metals with high fluidity, which have a low degree of oxidation during operation.

Primarily these are aluminum, copper, bronze and brass.

Related topics:

Source: https://electrosam.ru/glavnaja/jelektrooborudovanie/elektrody-dlia-svarki/

How to make electrodes for welding with your own hands

I had one friend, a girl with a fragile figure, a welder. In everyday life, no one would have suspected that she was proficient in such a non-female profession. And only the holes from the sparks on the work pants could serve as indisputable proof that this was so.

And, believe me, none of her fellow welders could compare with her in the cleanliness and evenness of the laid welding seam. She shared with me one of her many professional secrets - how to make electrodes for welding with your own hands .

To begin with, an educational program about what electrodes are and what they are made of

Electrodes are generally divided into two classes: consumable and non-consumable. We will talk about consumable electrodes, which are widely used when performing welding work at home.

Industrially manufactured electrodes are a rather complex product, the basis of which is low-carbon, alloyed or high-alloy wire, which is covered with a complex layer of additional substances.

These additional substances are needed in order to form a special atmosphere around the hot electrode, preventing access to it by oxygen and nitrogen from the atmosphere.

In addition, the additives contained in the layer alloy the steel and remove harmful impurities from it.

Electrode structure

A list of tasks in the production of a welding seam and the substances contained in the surface layer of the electrode, with the help of which these tasks are solved:

1. Slag-forming substances that protect metal from nitrogen and oxygen. They include manganese ore, kaolin, titanium concentrate, chalk, marble, feldspar, dolomite, and quartz sand.

2. Deoxidizers that remove oxygen from molten metal. Manganese, silicon, aluminum, and titanium in the form of ferroalloys are used.

3. Gas-forming components that create a gaseous environment during the combustion of the coating, protecting the molten metal from oxygen and nitrogen in the air. These are mainly dextrin and wood flour.

4. Alloying substances that give the weld metal special properties - strength, heat resistance, wear resistance, increased corrosion resistance. For this, chromium, manganese, titanium, molybdenum, nickel, vanadium and some other substances are used.

5. Stabilizing elements that promote ionization of the welding arc - sodium, potassium, calcium.

6. Binders that serve to bind the coating components to each other and the entire coating to the electrode rod. The main binder is potassium or sodium liquid glass (silicate glue).

However, it happens that it is necessary to urgently apply a stitch, but there are no electrodes and there is no opportunity to run to the store either. Then my friend’s advice on making electrodes from steel wire with your own hands will help you.

Manufacturing of electrodes

For this purpose, take steel wire of the required diameter. Typically this value ranges from 1.6 to 6 mm. Cut the wire into the number of pieces you need, 35 centimeters long. Prepare in advance a coating for the electrodes, which consists of a mixture of crushed chalk and silicate glue. Coating technology also matters: simply dip the electrode vertically into the mixture and slowly pull it out, leaving the upper end of the future electrode dry (about 3.5 centimeters).

Dry the electrodes in a vertical position, hanging them from a rope using a regular clothespin. Dry the electrodes until hardened. Sometimes, for speed, you can dry the electrodes in an oven with the air on.

Your electrodes are ready!

Welding electrodes

“The need for invention is cunning,” as my mother used to say. I hope that making welding electrodes with your own hands is just a necessary measure, which sometimes is the only way to quickly solve some problem.

So, you’re welcome to our store! From us you can inexpensively purchase electrodes with a diameter of 2.5-3.5 mm. at a price of 450 rubles per pack weighing 5 kilograms - enough for a long time!

Our address: Nakhodka, st. Ugolnaya, 59, hardware store. Our contacts are here.

Source: https://magnat4.ru/elektrody-svarki/