A Beginner's Guide to Arc Welding. The simplest welding methods: how to learn to weld metal yourself

Today, the industry has learned to create very strong permanent connections using various welding techniques. This process was invented at the beginning of the last century, and in a fairly short period of time it not only became firmly established in industrial production, but also found great application in all sectors of our life.

This material discusses in an accessible form the basics of welding using the example of one type of welding - manual electric arc, since it is the most popular method of welding in the household. Naturally, this is also the most accessible method for the majority of those interested.

What is welding?

The classic definition of the welding process is: “The process of creating inextricable connections through the establishment of interatomic relationships between parts that are connected during the process of heating and/or plastic deformation”. Keeping in mind the phenomenon of diffusion, it is known that in hot water the process of interpenetration is accelerated. Welding is very similar to diffusion, only the two parts are heated using a high-temperature electric arc generated by the welding machine. Under its influence, melting and interpenetration of the materials of the parts occurs. A weld appears, which consists of the materials of both parts and other chemicals introduced by the consumable electrode (element of the welding machine). There are many versions about the strength of this seam, some believe that 1 cm of the weld seam can withstand 100 kg, others claim that it is more, but everyone agrees on one thing: the strength of the weld seam is not inferior to the strength of the base metals of the parts. In addition to defining the main concept, the theoretical foundations of welding also include the physical and chemical processes occurring during welding.

What happens during welding from the point of view of chemistry and physics?

Let's consider a diagram of the welding process using electric arc welding as an example.

Electrical voltage is supplied to the electrode and to the part, but only with different polarities. As soon as the electrode is brought to the part, an electric arc immediately ignites, melting everything in its field of action. At this time, the electrode material is transferred dropwise into the weld pool. In order for the process not to stop, and this will happen when the electrode is stationary, it is necessary to move the electrode in three directions at once: transverse, translational and stably vertical (Fig. 2).

After all the manipulations, the welder removes the welding machine and the weld pool, solidifying, forms the same welding seam. This is the chemistry and physics that happens during electric arc welding. Naturally, with other types of welding, the mechanisms will be different. For example, in the form mentioned, the main thing is the melting mechanism, and when pressure welding, the welded surfaces are not only heated, but also compressed using sedimentary pressure. Let's take a closer look at the classification of welding types.

Types of welding.

There are three main classes of welding work, each of which has many subtypes.

The first class is heat welding. These include:

beam welding;
electro-beam;
plasma;
electroslag;
gas-flame;
electric arc.

The second class is thermomechanical welding. It contains the following varieties:

high frequency current welding;
blacksmith's;
diffusion;
contact

Third class - mechanical welding. These include:

cold welding;
ultrasonic;
explosion welding;
friction welding.

Each type is applicable to different metals and parts, for example, friction welding is used to weld drills, cutters and dissimilar metals, and cold welding (forging) is used to weld ductile metals: copper, tin, aluminum, etc. Each of the three classes of welding also has its own specifics, for example, each type of electric welding requires different electrodes. They are:

melting (rods made of copper, nickel, aluminum alloys, steel);
non-consumable (tungsten, graphite and carbon rods).

They also differ in the types of coating: rutile, cellulose, basic and acidic. All of them are relevant for welding various materials and for working in different spatial positions of the welder himself.

In everyday life, the need to weld objects periodically arises. Very often such a need arises in the private sector. For a large number of jobs, you can turn to experienced welders, but for small jobs it is better to use an inverter welding machine.

This is the simplest, most affordable and convenient type of welding. It is available for everyone to work with. To do this, you need to know the principles of the welding process.

Welding with an inverter has become a breakthrough in the field of welding machines, since outdated transformers are quite heavy and difficult to use. The advantage is that with inverter welding, spatter occurs less than when welding from a transformer.

An inverter is a welding machine that allows you to connect sheets of metal using an electric discharge. It has a distinctive feature: it has light weight and maximum capabilities, thanks to which he has access to work previously carried out by heavy and complex devices. The weight of the device depends on its power (from 3 to 7 kg).

You can transport it using a handle or strap. Cooling is provided by ventilation holes in the housing. This device consumes electricity, which flows only for arc work, and she carries out the welding process itself.

The device is insensitive to voltage changes. If there are constant fluctuations, you should pay attention to the required voltage, which is indicated in the inverter’s passport.

Displayed on the surface of the device control knobs and indicators:

turns on and off with a toggle switch;
the voltage and current values are set using knobs on the front panel;
the panel has indicators informing about power supply and device overheating;
The outputs (“+” and “-”) are located on the front panel.

Additionally included in the set 2 cables available. One of them ends with a holder for the electrode, and the second has a clip in the form of a clothespin for securing the product. The device is connected via a connector located on the rear panel of the device.

Principle of operation

An inverter is an electronic device that operates from the electrical network. When old welding machines are turned on, a strong and huge jolt of electricity occurs, which may result in a power outage.

The inverter has storage capacitors, accumulating electricity and ensuring uninterrupted operation of the network. They gently ignite the arc of the inverter.

It is worth paying attention to the fact that electricity consumption depends on the diameter of the electrodes. The larger it is, the greater the consumption. In this regard, in order not to burn household appliances, before working with the inverter, it is necessary to calculate the maximum possible amount of electricity that will be consumed by the device.

It is worth considering that for each electrode diameter there is a minimum current, i.e., if you try to reduce the current, the seam will not work. If the current increases, it will work, but the electrode will quickly burn out.

The arc comes from the connection between the metal portion of the electrode and the metal being welded. Electrode and metal begin melt under the influence of arc temperature. The molten parts in its place form a bath. The electrode coating melts, part of which goes into a gaseous state and blocks the bath from oxygen. The other part of the coating (in a liquid state) protects the metal from air during welding and during the cooling process.

After welding and cooling of the metal, the liquid part is slag, covering the seam from the outside. After cooling, the slag is removed by tapping with a hammer.

The electrode melts during the welding process. So that the arc does not go out, you need to maintain its length, i.e. the distance between the metal and the electrode. This can be done by inserting the electrode into the welding site at the same speed and exactly along the seam joint.

With a short arc (about 1 mm), the metal is heated over a small area, and the weld comes out convex. At the point where the seam and metal meet, a defect such as an undercut (a parallel dimple near the seam) may appear. It reduces the strength of the seam.

A long arc is unstable, poorly protected from air, almost does not heat the metal, and the weld is not fully deep. Normal arc size - from 2 to 3 mm. A constant gap of this size will form a normal seam with good penetration.

To work with welding, the following protective elements are required:

Necessary prepare a safe place for welding:

Free space, absence of everything unnecessary.
Good lighting.
The work is performed standing on a wooden floor, which protects against electric shock.

After this it is necessary adjust welding current(depending on the thickness of the metal and parts) and select an electrode (2−5 mm). Usually the strength of this current is indicated on the device body. Electrodes must be selected based on the brand of welding materials. Next, connect the ground terminal to the surface to be welded.

To obtain a reliable and high-quality connection before starting work metal should be prepared. Use a metal brush to remove rust from the edges, which need to be treated with a solvent (gasoline, white spirit). It is important to prevent the presence of grease and paint materials on the edges.

For beginners, it is better to make a seam in the form of a roller on a metal sheet with a large thickness. The sheet must be placed horizontally on the table. There's chalk on it a straight line is drawn for guidance in the work along which the roller will be laid. To start welding, you need to ignite the arc. You can do this in 2 ways:

chirping;
tapping.

You can strike and hold the arc in both ways. Next comes the welding process itself, which produces a weld seam. Metal scale on top of the seam needs to be removed by tapping with a small hammer or hard object. The ability to control the length of the arc will provide excellent results.

The beauty of the seam is influenced by:

electrode inclination angle;
diagram of transverse and longitudinal movements;
speed of electrode movement.

How to cook a vertical seam

Welding such seams (slanted and ceiling) is a rather complex process. This is due to the fact that even molten metal is subject to the law of gravity. He is constantly pulled down, which causes difficulties. Beginning welders will need to spend a lot of time learning how to do this.

There are 3 technologies for vertical seam welding:

Triangle. Used when connecting parts with a thickness of no more than 2 mm. Welding occurs from bottom to top. The liquid metal is on top of the solidifying one. It flows down, thereby covering the suture roller. The flowing slag does not interfere, since it moves along the solidified bath, which exits at a certain angle. Externally, the weld pool looks like a triangle. In this method, it is important to move the electrode accurately to completely fill the joint.
Herringbone. This type of welding is suitable for gaps between workpieces equal to 2-3 mm. Along the edge from the depth towards you, you need to use an electrode to melt the metal to the entire thickness of the workpiece and, without stopping, lower the electrode to the gap. After melting occurs, do all this along the other edge. You need to continue from the bottom to the top of the weld. This results in a uniform arrangement of molten metal in the gap space. It is important to prevent the formation of undercut edges and metal leaks.
Ladder. This method is used when there is a large gap between the workpieces being joined and little dulling of the edges (or its absence at all). Welding is carried out in a zigzag manner from one edge to the other from bottom to top. The electrode stops at the edges for a long time, and the transition is made quickly. The roller will have a small cross-section.

Welding polarity

Melting of the metal during the welding process is carried out under the influence of the heat of the arc. It forms between the metal and the electrode when they are connected to opposite terminals of the welding device.

There are 2 options for performing welding work: direct and reverse polarity.

In the first case, the electrode is connected to the minus, and the metal to the plus. There is a reduced introduction of heat into the metal. The melting point is narrow and deep.
In the second case, the electrode is connected to the positive, and the metal to the negative, resulting in a reduced heat input into the product. The melting point is wide, but not deep.

When choosing welding, it is necessary to take into account that the network element connected to the plus heats up more. Thick metal is welded with direct polarity, and thin metal with reverse polarity.

In addition to the fact that welding can connect parts, it you can cut them. To do this, you need to increase the current and cut off the part or corners. It’s just not possible to do it exactly.

By using this guide, you can gradually improve your skills and use inverter welding without any problems in the future. The main thing in this matter is practice.

It's no secret that many people learned to weld on their own. There are really a large number of such people, and many of them can use the practical skills acquired at home with high efficiency. However, sometimes it is better to gain some theoretical knowledge first before getting down to business. Let's talk about what welding is for beginners, how it is characterized, and why it is best for beginners to use an inverter.

Briefly about welding inverters

The inverter is electronic. Quite accurate, economical and easy to use. The main load during operation falls on the welding network. The advantages of an inverter, especially for beginners, are that they have storage capacitors. They are necessary to collect a certain amount of electrical charge, which ensures uninterrupted operation. Many people have probably noticed that when working with old welding machines, the voltage in the network begins to jump sharply. Under such conditions, any household appliance may burn out. So, there is no such shortage. In addition, a smooth arc start is ensured, which is necessary to ensure the quality of the seam.

A little theory

When connecting metal parts, a huge number of processes take place. Most of them are hidden from human eyes, while others are obvious. Thus, the welding process itself can be divided into several simple stages. At the first, an arc is formed, which indicates a short circuit between the electrode and the metal. At the second stage, a high temperature is created (up to 7 thousand degrees), which allows you to melt any metal. As a result of the melting of the electrode and the edges of the metal products, a connection occurs - obtaining. This ends the process. The electrode plays a big role. It consists of an alloy, on the surface of which a powder composition is applied. The powder is used to maintain uniform arc burning, and the electrode itself is necessary to form a weld pool without oxygen.

for beginners: step-by-step instructions

Before you begin the work, you will need minimal ammunition. Thus, it is not recommended to carry out work without a special protective helmet and rough gloves. Well, in addition to this, it is advisable to have an old jacket made of coarse cotton (for example, denim) fabric that will not burn from a spark.

Next, you need to adjust the welding current and select the correct electrode. Products with a diameter of 2-5 mm are suitable for inverter welding. The welding current is set based on the thickness of the workpiece and the material. To avoid sticking, the electrode is brought smoothly to the surface to be treated. After this, you can connect the ground terminal to the part.

The welding process begins with ignition of the arc. The electrode is brought to the surface at a slight angle. To activate it, you need to touch the surface to be welded several times. During operation, the electrode must be kept at a distance of its diameter from the surface. In principle, welding with an inverter is quite simple for beginners. Now let's move on.

Gap control

The arc gap is of great importance during welding work. This gap is the distance between the electrode and the metal, which is formed during welding work. If the distance is insufficient, the seam will turn out convex, since the metal at the joint will not have time to warm up. If the gap is too large, this will lead to an unstable arc, which, in turn, can lead to poor weld quality. In particular, the connection turns out to be crooked.

For good penetration and a high-quality seam, it is necessary to choose the optimal gap. We can safely say that learning to maintain a constant correct distance is the most difficult skill. But if you learn how to do it, arc welding for beginners will soon turn into welding for professionals. Do not forget that during the process the electrode gradually melts, therefore, if you do not move it, the gap will increase. Watch this more carefully and everything will be fine.

Forming the correct seam

I would like to note that for beginners this means not only maintaining the required clearance. There are several more important requirements that it is advisable to comply with:

speed and electrode;
current strength;
angle of inclination of the electrode.

Changes when working with different materials. That is why in some cases the electrode is led quickly, in others, on the contrary, slowly. In this case, the thickness of the metal being connected affects the current strength. The thicker the product, the more current must be supplied to the electrode. And the thickness of the seam and weldability depend on the angle of inclination of the electrode. All this must be taken into account when performing work. In principle, manual welding for beginners of simple parts is within the power of everyone. Experience will come only if you constantly practice and train, creating increasingly complex seams.

About polarity when welding

It is necessary to understand that there is direct and reverse polarity. If we are dealing with the first, then the heat input into the metal product increases. Consequently, a narrow but rather deep melting zone is formed. This technology is used for precise processing of fairly thick sheets.

If you need to create a high-quality seam on a thin sheet, then reverse polarity is used. It is characterized by the fact that there is a reduced input of heat into the product, therefore, the seam is wide, but not too deep. Currently, both technologies are actively used. It is quite possible that at the beginning of the journey it does not make sense for a novice welder to understand polarity, but after making some connections this knowledge will come in very handy.

for beginners: working with thin sheets

As noted a little above, thin metal products must be worked with reverse polarity. This is due to the fact that they are quite easy to burn through, which will ruin the workpiece. Reverse polarity is installed directly on the inverter. At the same time, the current strength also decreases to normal. In this case, the electrodes are connected “plus” to the inverter, and “minus”, respectively, to the metal sheet. This will allow you to get high quality seams and not burn through the sheet. However, if you are a beginner, then you need to choose a workplace so that the seam is visible to you. In this case, you will be able to control the process. Over time, you will perform the work automatically, but this will only come with more experience.

Conclusion

So we talked to you about what it is and how welding with an inverter is performed for beginners. "Resanta", for example, is welding equipment of good quality. Moreover, it is ideal for beginners. This is due to its exceptional ease of use. The line includes models that are more suitable for amateur welding, and there are expensive professional inverters. The last option is unlikely to suit a beginner. Such equipment is more often used in industry.

Of course, if you are going to work as a welder, then you will need an inverter for professionals. It costs a lot, of course, but allows you to perform welding work with a wide variety of materials. Don't forget about personal protective equipment. You cannot look at the arc without special glasses or a mask. Firstly, this makes your eyes very tired, and secondly, it negatively affects your vision. This is why it is imperative to use a mask. In principle, this is all that can be said about inverter welding for beginners. There is nothing complicated here, but it is necessary to strictly follow the technology, and then the seam will be durable and of high quality.

Comments:

People who live in their own home, have a dacha or at least a private garage, periodically face the need to carry out welding work. As a rule, they use the services of professional welders. However, many, if they want to save money or simply out of interest, cook on their own, using specialized equipment for this. If you are one of those people who like to do everything on their own, but you have never had to work with electric welding before, there is no need to be afraid. You can learn everything, including electric welding. The most important thing is to familiarize yourself with the theory and practice a little. And very soon you will produce seams no worse than those of a professional welder.

Preparation for work and selection of electrodes

Before you start learning to weld with electric welding, you should prepare the required tools and protective accessories. Prepare the following:

welder's mask;
protective clothing and gloves;
hammer for removing slag;
electrodes;
metal brush;
welding machine.

Protective clothing must be made of dense material.

Before starting work, remember one simple rule: electrodes must be selected in accordance with the thickness of the metal, and the current must be set according to the selected electrode. The calculation is extremely simple. For example, you are using a welding transformer.

In this case, 1 mm of electrode will account for about 30-40 A. If you work with a welding inverter, then 3 mm of electrode will correspond to 80 A. When the current increases to 100 A, it will already be possible to cut metal.

The place for welding work should be convenient for you. There are no special requirements for it. Be sure to bring a bucket of water to your workplace.

Prepare everything you need for work, as well as the workpieces themselves. Thoroughly clean the weld seams using a metal brush. Until you have experience, if possible, position workpieces using a vice or clamps.

In order to understand the technology of working with electric welding, first practice welding beads on a flat area. In this case, it is best to use 3 mm electrodes - the most popular and universal option.

You should not hope that you will be able to learn how to weld with electric welding “with 1 electrode”. Prepare at least a pack of electrodes. They're relatively cheap, but you'll get plenty of practice.

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Step-by-step instructions for working with electric welding

To begin, attach the work clamp to the workpiece and insert the electrode into the holder. Next, you will need to light the arc. To make everything simpler and clearer, while working, imagine that the electrode is a pencil. It will need to be installed at an angle of about 70 degrees to the workpiece. Having chosen the optimal location of the electrode, move it across the workpiece at a speed of approximately 7-10 cm per second. If a characteristic crackling sound and sparks appear, everything has been done correctly.

Next, at approximately the same angle, you will need to touch the workpiece and immediately lift the electrode so that a gap of 3-5 mm is obtained. As a result, the arc will begin to burn. In this case, both the metal of the workpiece and the arc itself will melt. You must try to maintain this gap and at the same time move the electrode horizontally.

If the electrode begins to stick, shake it from side to side, tearing it away from the workpiece, and re-ignite the arc.

If the electrode sticks, this is a clear sign that the current is too low. Therefore, it needs to be increased slightly. Practice, change the current until you find a value at which the arc length between the part and the end of the electrode will be 3-5 mm.

Once you have learned how to strike an arc and maintain it in a stable state, you can learn how to build a bead. Clamp the arc and begin to smoothly move the electrode along the welding seam, i.e. horizontally. During such movement, you need to make movements with an amplitude of about 2-3 mm, as if “raking” the molten material towards the arc crater. This is how a beautiful seam with barely visible waves of deposited metal is created. The seam is quite reliable.

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How to make different seams?

However, the seam discussed above is not the only one available. Before moving on to studying different seams, you need to remember that the main condition for high-quality welding is proper maintenance and movement of the arc. If the arc is too long, the molten metal will begin to oxidize and nitrate, its drops will be splashed across the surface, and the seam will have a porous structure.

The principle of electrode welding.

The movement of the arc can be carried out in 3 main directions. In the first case, translational motion occurs along the axis of the electrode. In this case, the length of the arc will be maintained in normal condition. It depends on the melting rate of the electrode. As it melts, the distance between it and the weld pool will increase. To prevent this, move the electrode along the axis. Due to this, the arc will have a constant length.

When the electrode is moved longitudinally along the axis of the seam, the so-called thread welding bead discussed earlier. The thickness of such a seam depends on the diameter of the electrode used and how quickly it moves. The width of the roller in most cases exceeds the diameter of the electrode by 2-3 mm. The bead is already a weld, but it is too narrow. It is usually not enough to create a strong connection. For this reason, when moving the electrode along the axis of the seam, you need to make another movement, but this time across.

A seam of the required length can be obtained by transverse movement of the electrode. In this case, reciprocating oscillatory movements are performed. In each specific case, the width of these fluctuations is determined individually. First of all, it is influenced by the size and position of the seam, the shape of the groove, the characteristics of the working materials, as well as the requirements for the welding joint itself. In most cases, the width of the seam does not go beyond 1.5-5 diameters of the electrode used.

When working with electric welding, the appropriate arc movement should be selected in such a way that the edges of the joined products are fused to form the required amount of deposited metal and a weld of a given shape.

Welding is one of the rather complex, but extremely popular technologies for working with metals. Wherever you look, welded joints are always used. Not a single industrial production, construction company, repair or service enterprise can do without this process. Welding becomes indispensable in the construction and improvement of one’s own home.

But here’s the problem: welding work requires a certain level of preparedness. You can, of course, if necessary, contact welders through advertisements, or contact your friends who have the necessary skills. But it’s better to ask yourself the question - how to learn how to work with electric welding yourself, so as not to be dependent on anyone. Today, when home welding equipment has ceased to be a problem, the ability to carry out such work, especially for the owner of an individual home, is an invaluable plus, since many problems will simply cease to exist.

But first of all, you need to understand the basic concepts of electric welding and purchase equipment. Welding is a technological process where the quality of work directly depends on the equipment of the workplace.

The very essence of electric welding is as follows. The power plant generates a powerful welding current, which is supplied through cables to the work station. An electric welding arc is created between the electrode and the surface of the metal being welded - a stable discharge characterized by the highest temperature values. This leads to melting of the metal and filler material. A so-called weld pool is formed - an area of \u200b\u200bthe melt, by controlling and directing which the welder forms the seam. After removing the arc, crystallization of the molten metal occurs and a strong monolithic connection of the parts is created.

This very simplified scheme is implemented in several welding technologies:

Most widespread is manual arc welding, which, according to existing terminology, has the abbreviation MMA (from the English name “ Manual Metal Arc"). The main feature is the use of fusible electrodes with special coating. Advantages - no particularly complex technical support or gas equipment is required. The disadvantage is that welding can only be done with ferrous metals or stainless steel.

In the overwhelming majority of cases, if welding is considered at the household level, then this technology is meant.

Welding using TIG technology allows you to work with alloy steels and some non-ferrous metals. The term " Tungsten Inert Gas» speaks for itself: tungsten and inert gas. In this case, an arc is created between the surface to be welded and an infusible tungsten electrode, and a filler rod of one type or another is introduced as a filler. At the same time, a protective inert gas is constantly supplied through a welding torch with a heat-resistant ceramic nozzle, which ensures the cleanliness of the seam.

Welding using this technology has a lot of advantages, but it requires special equipment and highly qualified workers.

Metal

Active

Gas

This technology allows you to make high quality seams in any plane and with very high productivity. To some extent it is even simpler than M MA, but requires complex and rather bulky equipment - the welding machine itself, a wire feeder, a gas cylinder device, a torch with a special sleeve through which the wire and shielding gas flow.

There is also spot electric welding - SPOT, which is widely used, in particular, in the body areas of car service enterprises. It also requires special, sophisticated equipment, and is practically not used at home.

Manual arc welding MMA - what is required for work?

Any beginner always starts by mastering the techniques of manual arc welding (MMA), so all the questions discussed below will be devoted specifically to it.

To start practicing on your own, you need to prepare certain equipment, equipment and consumables.

Arc Welding Machine

To carry out welding work using MMA technology, one of three types of devices is used:

A welding transformer is one of the simplest types of equipment. The principle of operation is elementary - the mains voltage of 220 V (or 380, for a three-phase network) is converted into a lower one, about 25 - 50 V, but due to this the current value increases sharply. The advantages of such a circuit are its simplicity, high reliability and ease of maintenance , high power levels. Such devices are inexpensive, which probably largely determines their prevalence.

The transformer has many more disadvantages - the welding arc from alternating current is not stable, there are frequent cases of electrodes sticking, large spattering of metal, and the seams are not neat. In addition, special electrodes will be required specifically for “change”. Welding transformers are very dependent on the mains voltage, and during operation they can seriously drain the network. They are not distinguished by their compactness and lightness. In a word, starting training with such equipment is undesirable. As a rule, working on such devices will require good skills.

MMA welding rectifiers differ from transformers in that they produce direct current at the output. It is much easier to work with them, since the “constant” arc is much more stable, and the seams are more accurate.

However, shortcomings remain– the same massiveness and dimensions, even larger than those of welding transformers, dependence on the supply voltage and a large load on the network. They are more expensive in price than transformer devices.

Without exaggeration, we can say that a literal revolution in welding technologies was made by devices operating using an inverter circuit. AC mains voltage 220 V with a frequency of 50 Hz goes through a whole cascade of frequency and amplitude transformations, and the required direct current with the highest degree of stabilization is obtained at the input. All processes are controlled by a microprocessor assembly, which allows the required adjustments to be made with a high degree of accuracy.

The most modern solution - welding inverter

All this gives a whole “bouquet” of advantages of such a device:

— The equipment can easily withstand quite serious fluctuations in the mains voltage, which is especially important in suburban villages, where such problems are a very common occurrence.

— At the same time, inverters, compared to other devices, have minimal energy consumption - they practically do not overload the network.

— Stabilized current and the possibility of its precise adjustment allow you to make precise and neat seams. There is virtually no spattering.

— The device is compact and lightweight.

A wide range of similar devices is produced - from household-grade inverters to professional equipment. For beginner welders, this is the most optimal solution. Prices for high-quality inverters are quite high, but, firstly, they tend to decrease, and secondly, such a one-time purchase will fully justify itself. And quite a few inexpensive devices of very dubious assembly have appeared for sale. Therefore, it is very important to approach the problem correctly inverter selection - You need to pay attention to a number of important nuances:

Maximum welding current. If the device is planned to be used in a household environment, then, as a rule, stop on models with a value of 150 - 200 A. this is quite enough to work with electrodes with diameters up to 4 mm.
Resistance of the electronic circuit to changes in mains voltage. High-quality inverters must withstand fluctuations within ± 20 ÷ 25%.
The inverter must have a forced cooling system that operates constantly when the power is on, or be equipped with an automatic system that starts ventilation at a certain radiator temperature.
We should not forget about the power consumption of the device - it can be of the order of 2 ÷ 3 kW for small models, but can reach larger values for devices semi-professional or professional class.
What about m Many people simply don’t know: the parameter that determines the permissible duration of the welding process is the on-time (ON). No device can operate without interruptions, and the parameters must indicate the duty cycle, expressed as a percentage of the total duration of operation of the equipment. For household-class models this is usually about 40% - nothing can be done, this is the price to pay for the compactness of the device. In practice, this means that the “rest” period, in this case, is 1.5 times longer than the welding time, for example, 1 minute of continuous work will then require at least a minute and a half pause.
It will be very convenient for novice welders if some useful functions are implemented in the device circuit:

— “HotStart” significantly facilitates the initial ignition of the welding arc. The electronics automatically pulse increases the current value at the moment of ignition.

— "ArcForce" will help to cope with the eternal problem of beginners - sticking of the electrode to the metal surface. By reducing the required gap between the electrode and the metal, the current increases, preventing this nuisance.

— “AntiStick” is a function that will prevent the machine from overheating if sticking cannot be avoided. In this case, the power will simply turn off automatically.

Another important tip. The “Achilles heel” of inverters is the certain difficulty of carrying out repair work in the event of a circuit failure. When choosing a device, it is better to give preference to models with a multi-board electronic circuit layout. Buying such devices is a little more expensive, but diagnosing breakdowns becomes easier, and maintainability is much higher.

Video: how to choose a welding inverter

Welding leads, electrode holder, ground clamp

Welding inverters, as a rule, are already equipped with wires, an electrode holder and a ground clamp. However, when purchasing, you should also pay close attention to these elements - sometimes you can run into low-quality products.

Welding wires must be in flexible rubber insulation and have reliable brass contact plugs suitable for the connectors of a particular device. The cable cross-section must be at least 16 mm² if the device is designed for currents up to 150 A, 25 mm² - at 200 A and even 35 mm² if it is intended to work with currents of 250 A and higher. You should not chase a long length of wires or extend them yourself - this can lead to overload of the electronics and failure of the inverter.
The electrode holder is the most important element of a welder’s equipment, since it is what the master manipulates during the work process. You should not use homemade “forks” for work - this is quite dangerous in terms of light burns to the eyes or electric shock. The most common and convenient today are plier-type holders - “clothespins”. Some are convenient, allow you to quickly and easily replace the electrode, are well insulated on all sides and provide adequate safety.

One of the most common are plier-type “clothespin” holders.

The holder must have a reliable clamp for the electrodes, allowing them to be placed not only perpendicularly, but also at an angle of 45º. You need to take the time to check the material of the contact part - it should be copper or brass, but not copper-plated steel. This is a clear sign a cheap fake that can be easily identified with a small magnet. It is necessary to check the reliability of fixation of electrodes, especially small diameters (2 mm) - this is often a problem with low-quality plier-type holders.

An important factor is the convenience of the holder, its balance, “weight distribution” - working with it should not cause rapid hand fatigue. It should have a handle long enough to allow you to take the most comfortable hand position, and a corrugated surface to prevent slipping in the palm wearing a mitten. Do not forget that the maximum welding current value is also determined for the holders.

The clamp for connecting the ground must have a powerful spring, a reliable connection to the wire, brass contacts for crimping a metal workpiece, connected by a copper busbar.

Welder equipment

First of all, for welding work you will need a mask or shield. Shields often come with inverters, but they have an inconvenience - you need to hold it with your free hand, and this is not always possible. It is better to purchase a full mask.

This piece of equipment protects the eyes from light burns, covers the face from metal splashes or sparks, and the respiratory system, to a certain extent, from rising gases. At the same time, the light filter must provide good visibility of the seam being applied when the arc is ignited - selection is made individually. The light filter must be covered with protective glass.

The mask itself is made of heat-resistant plastic. It should not be heavy and bulky, causing rapid fatigue. It is necessary to check the comfort of the headrest and its fixation in the desired position, the possibility of adjustment to the required size.

Masks - “chameleons”, equipped with special liquid crystal filters that instantly change light conductivity at the moment of arc ignition. The convenience is undeniable - there is no need to constantly fold back the mask to visually control the completed seam, and the process of igniting the arc is simplified. Such masks have certain degrees of adjustment of response speed and degree of darkness - this is another significant advantage. Their disadvantage is their rather high price.

To work, you will need special clothing, made of durable, dense fabric that prevents instant melting or burning when exposed to sparks. (eg tarpaulin) Patch pockets on a jacket or pants are strictly prohibited.

Shoes must be leather, fully closed, and their tops must be securely covered by the legs. Hands must be protected with leather or thick canvas mittens or gloves (gaiters) with long cuffs that completely cover the wrist area.

To carry out welding work, in addition, you will need a special hammer for chopping slag - cleaver, iron brush for cleaning metal surfaces. Cutting workpieces and cutting parts (chamfering, etc.) will require a grinder machine with cutting and grinding wheels.

What electrodes should I use?

Electrode represents a steel rod covered with a layer of coating. The rod is both a conductor for welding current and a filler material. Coating, when exposed to high temperatures, creates a protective layer of slag and gas, protecting the weld from instant oxidation by oxygen and nitrogen in the air.

It is very important to choose the right electrodes

There are situations when the equipment is good, and everything seems to be done according to the rules, but the weld does not work. Perhaps the reason lies in the incorrect selection of electrodes. Alas, many novice craftsmen select them, focusing only on the thickness of the rod section, losing sight of the other characteristics. Meanwhile, the classification of electrodes is quite complex and diverse. Of course, you can get advice when purchasing, if, of course, the seller himself understands this. But you can try to figure out some issues on your own.

For example, an electrode E42 A-U OHI-13/45— 3.0-UD (GOST 9966— 75) or E-432(5) – B 1 0 (GOST 9967— 75). What can numbers and letters tell us?

E42 A– a special designation indicating the mechanical and strength properties of the seam being created. A characteristic more required for engineering calculations.
UOHI -13/45 – The brand of the product is encrypted here. which is assigned to it by the manufacturer.
3,0 – the diameter of the metal rod is 3 mm.
Letter "U" indicates that it is intended for welding carbon or low-alloy steels - what is most often required at home. You can find designations "L", "T", "V" - these are electrodes for alloyed and in instrumental steels of various types, and "N" - to create a surfacing layer on the metal surface.
Letter "D" in this example it speaks of thick coating. A thin layer will be indicated "M" , average - "WITH" and very thick - "G". Preference should be given to thick coating.

According to the following GOST, the decoding is as follows:

E-432(5) – information for specialists about the physical and chemical properties of the deposited additive.

"B" is a classification of coating coating. In the example given - the main thing. Besides You can find the following designations:

- "A" — acid-type coating, suitable for permanent, And for a break, for any types of seams, but produces strong spattering.

- "B" — the main one, used for welding powerful thick parts using reverse polarity.

- "R" — rutile coating is one of the most common, perfect for a novice welder and for work at home.

- "C" - coating with a cellulose component. It is very convenient for large-scale work, but requires special qualifications of the welder, as it does not tolerate overheating.

— “RC”, “RCZh” — combined type. The letter “F”, in addition, indicates the inclusion of iron powder in the composition. Mainly used by qualified specialists for special types of work.

The next number indicates the spatial arrangement of seams that can be made with this electrode.

— "1" - universal;

- "2" - everything except vertical top down;

— "3" - “ceiling” and vertical are unacceptable, just as in paragraph 2;

- "4" — the electrode can only perform lower seams.

The last digit of the marking is an index indicating the parameters of the required welding current. The data is summarized in a special table, taking into account the type of current, the value of the open circuit voltage of the device, and the required polarity. Without going into details, just a few words about what needs to be taken into account. There are ten gradations in total, from «0» before "9" . For alternating current, any can be used except «0» . When “constant”, the polarity of the connection will not matter for indexes "1", "4", "7" . Electrodes "2", "5" And "8" - exclusively for straight polarity, and "0", "3", "6" , And "9" - only for reverse.

The diameter of the electrodes is selected depending on the thickness of the parts being welded. Simplified, you can focus on the following parameters:

— For workpieces up to 2 mm thick — Ø 1.5 ÷ 2.5 mm;

– 3 mm – Ø 3.0;

– 4 ÷ 5 mm – Ø 3.0 ÷ 4.0;

– 6 ÷ 12 mm – Ø 4.0 ÷ 5.0;

- over 12 mm - Ø 5.0.

Video: classification of electrodes for manual arc welding

Preparation of the workplace

To start practical exercises, you need to prepare yourself a workplace:

It is best to work in the fresh air and open space - there is no possibility of fire in the building structures, and there is less exposure to toxic fumes.
There should be no flammable materials or liquids near the workplace.
In case of fire, you should prepare fire extinguishing agents - water, a fire-resistant cape made of thick fabric, sand. In this case, water can be used to extinguish the flame only when the apparatus is completely de-energized.

The optimal solution is a metal welding workbench

It is best to work on a metal workbench. You should consider the issue of fixing workpieces (vises, clamps, etc.). )
The extension cord must have a cable cross-section that matches the peak power consumption of the welding machine.
Before starting work, it is necessary to take measures to exclude the appearance of strangers, and especially children.

First practical steps

If everything is ready, you can proceed to practical actions. To begin with, it is best to prepare a sheet of metal, cleaned of dirt and rust - it is better to practice the first steps on it, without rushing to immediately weld any parts.

A mass clamp is attached to the workpiece. Good contact at the connection point is very important - it should be cleaned with a metal brush

It is best to start training with electrodes Ø 3 mm - it is easier to “get your hands on” with them. The value of the welding current in this case will be about 80 - 100 A. The electrode is inserted into the holder, and the reliability of its fastening is checked.

The first “exercise” will be to ignite and hold the welding arc. To do this, after turning on the device and lowering the mask, you need to either scratch the electrode on the surface of the metal, or knock several times on one place. A spark must appear, and now the most important thing is to keep the arc burning. To do this, it is necessary to strictly maintain the gap between the electrode and the metal surface. The position of the electrode is approximately 30 º from the perpendicular to the surface.

A normal gap is considered to be approximately equal to the thickness of the electrode rod - this is called a short arc. When inverter welding using high-quality and dry electrodes, there are usually no problems with arc stability. Increasing the gap to 4 - 5 mm results in a long arc, which will not produce a high-quality seam. Bringing the electrode too close to the surface may result in it sticking. In this case, you should immediately swing the holder to the side before the rod begins to overheat.

When maintaining an arc, remember that the electrode is constantly burning out, and its position relative to the metal surface must be adjusted.

Now you need to clearly understand the structure of the molten metal in the arc region. At the beginning of heating, a red liquid spot appears - this is not metal yet, but the melted coating of the electrode, which has created a protective layer. After 2-3 seconds, a bright orange or even whitish drop with a slight trembling or ripple on its surface will appear in the center of this spot - this is the weld pool, an area of molten metal. It is important to learn to clearly distinguish between the liquid slag and the bath itself - the quality of the seam being applied will depend on this.
As soon as the bath has formed, we begin to try to move it, smoothly moving the electrode without changing the gap. A drop of metal always moves to an area of increased temperature, so the bath will tend to follow the arc. For its part, the pressure of the arc pushes the bath somewhat in the opposite direction. Having worked practically and understood this principle, you can try to form a bead of deposited metal on the surface of the sheet.
To complicate the task somewhat, it is best to mark a line on the surface of the metal that is maintained when creating a weld bead. The electrode will move along the line with slight oscillatory movements to the sides - as shown in the diagram.

After applying this “seam,” you need to let it cool and then chip off the slag layer to visually assess the quality. Amperage adjustments may be required. This, for example, will be noticeable in uncooked areas - the current is clearly insufficient. An increased value may lead to burning of the sheet. All this is determined only experimentally; it is difficult to give any clear recommendations.

The first exercise is to create even rollers

Porosity of the seams and inclusion of slag particles in the metal structure are not allowed - this connection is not durable.

During practice, it will be possible to decide which direction of welding will be most convenient - towards you or away from you, pulling the bath behind the electrode or vice versa, pushing it forward. Many craftsmen still advise welding, if smooth and high-quality beads begin to be obtained, you can move on to the next stage - welding two workpieces.

Welded seams in spatial position can be lower, on a vertical plane (horizontal or vertical) and ceiling. Of course, you need to start from the bottom - the ability to perform the rest will not come immediately, as you gain experience.

Based on the location of the mating parts, seams are divided into butt, corner, tee and overlap. Each of them has its own characteristics of application, electrode movement, cutting and positioning of workpieces.
Welding of two parts begins with tacks, which will ensure a stable position of the parts when applying the main seam. Usually, for tack welding, the current is inserted 20-30% more, while working on a short arc. In this case, the tacks should not be closer than 10 mm from the edge of the workpieces or close to the holes. After applying tacks, it is possible to check the correct position of the parts and make the necessary adjustments.

First, you should learn how to apply single-layer sutures on thin, 3-4 mm workpieces. More complex options, with root boiling and filling, can be mastered; years with the simplest techniques, stable skills will be achieved.

You should not be afraid of such first failures - experience will definitely come

In a word, everything else will depend only on the efforts and regular practical training of the novice welder. It would be good if there was an opportunity to contact a specialist so that he could evaluate the results obtained. If not, you can compare the results of your work with videos shown on the Internet with master classes on arc welding. Experience, steadiness of hand, ability to choose the right parameters and self-confidence will definitely come.