How to learn how to cook with a welding inverter. How to weld metal with a welding inverter: video tutorials and tips

Among search queries, one and the same question is very often found - “how to cook inverter welding? Understand the intricacies of working with welding inverter It is not difficult, the operating instructions for this machine are available even to novice welders.

Thanks to the advent of welding inverters, the welding process has become much easier for both professionals in this field and beginners. These devices allowed the transition to better and faster welding. metal structures. At the moment, the technology of welding metal with an inverter has managed to spread so much that it has already managed to overshadow welding work using classic transformers, rectifiers and generators.

How does a welding inverter work?

The inverter welding machine is powered by alternating current. Its frequency must be equal to 50 hertz. Alternating current in the inverter comes from the consumer network and is fed to the rectifier.

The resulting electric current is converted inside the inverter. This is due to the work of special transistors. They increase the switching frequency of the current, which is then used for welding. After conversion, its frequency level reaches 20-50 kilohertz.

The increased frequency of the electric current is the main technical feature operation of the welding inverter. It allows you to achieve high productivity in the operation of the device and reduce the time spent on welding metals. This feature gives the inverter an advantage when compared with other types of welding machines.

After converting the current frequency in the device, its voltage is changed. It goes down until it reaches 70-90 volts. At the same time, the current rises to 100-200 amperes. Despite the high power of the generated current, the dimensions of the inverter are small. This is achieved due to the fact that there are no bulky induction coils in its design.

Welding thin metal with an inverter: a guide for beginners

The first recommendation for beginners in welding thin metal with an inverter is the correct polarity setting. It switches on the device itself. This parameter determines the direction of movement of electrons and depends on the connection of the cables to the hardware connectors.

When welding thin metal with an inverter, the polarity must be reversed. In this case, the electrons will move from the metal structure to the electrodes. With reverse polarity, the electrode elements will heat up much more. Due to this, the risk of burning through the metal is significantly reduced.

There are also three more tips for beginners in inverter metal welding.

TIP 1: watch a few videos on how to properly perform inverter welding of metal. They contain useful tips from welding professionals. Also, the video will help you see the correct welding technology.

TIP 2: learn proper ignition technique. There are two ways to ignite the arc in the welding machine - by tapping or striking on the metal being processed.

TIP 3: learn how to properly hold the welding machine. The inverter is best held over the metal being welded at an angle of 90 degrees. In this case, the welding seam will turn out to be of better quality.

How to weld thin metal with inverter welding

The technique of welding thin metal with an inverter involves a careful selection of operating parameters and individual components of the welding device. First of all, it is necessary to establish the strength of the current generated by the device. The thicker the structure to be processed, the stronger the electric current must be.

Next, select the electrodes suitable for welding. Their diameter should be the same as that of the welded structures. For example, if welding must be carried out on a sheet of metal 2 mm thick, then the same parameter for the electrodes must be identical. In this case, the current strength must be set within 35 amperes.

Before welding thin metal with inverter welding, it is necessary to check the operation of the welding machine on any unnecessary part. It is recommended to make sure that the metal does not burn through and leaves an even seam. If the welding is of high quality, then this means that the current strength and the thickness of the electrodes were selected correctly.

After checking, you can start welding thin metal. It is necessary to move the inverter with intermittent movements. This will help create a tighter seam that will reliably withstand external mechanical stress and possible deformations.

Inverter welding of thick and thin metal structures

The main problem when welding thin metal to thick metal with an inverter is that parts of different thicknesses require different polarities when welding. If thinner parts are welded with the reverse polarity set, then with products thicker than 3 millimeters, other parameters are required.

The thing is that thick metals are subject to welding at high temperatures. Otherwise, the parts will not warm up to the required level and the weld will turn out to be of insufficient quality. Direct polarization helps to solve the heating problem. It directs electrons from the electrode to the metal, which helps to heat it to an acceptable temperature. This makes thick metals ready for welding.

For this reason, before welding structures of different thicknesses, it is recommended to warm up thickened parts. This will allow them to be processed efficiently and welded tightly to thin metals. for welding metal products different thicknesses, it is best to install reverse polarity on the inverter. In this case, the current strength should fluctuate within 30-50 amperes.

How to cut metal parts with inverter welding?

Using inverter welding, you can cut metal of any thickness. To do this, it is necessary to increase the strength of the current generated by the device. For high-quality cutting of metal products, an electric current is suitable, whose power indicator will be equal to 140-160 amperes. It is also necessary to correctly set the polarization of the device. When cutting metal, you will need to activate the straight polarity of the inverter.

The technique of inverter cutting of metal parts is that the electrode is pressed into the surface to be treated until it forms in it through hole. After it appears, the inverter moves, and the process of creating new gaps takes place in the same way. It is recommended to warm up the metal before cutting. It is better to cut it in a vertical position - so drops of molten material will drain onto the work surface.

Pros and cons of using an inverter

In conclusion to all of the above, it is necessary to note the advantages and disadvantages of the welding inverter. Main positive moment in the use of this device - its not big weight. This helps to significantly increase the productivity of welding.

The other most important advantage of the inverter is the wide adjustment of the welding current. This allows the use of argon as an inert gas and non-consumable electrodes for welding. Also in the inverters there is an option to stop the supply of current in the event of a short circuit.

The most significant disadvantage of inverters is their high cost. These devices cost two to three times more than conventional welding machines. However, they do not have more serious protection against dust and dirt particles.

Very often, novice welders are wondering how to weld metal by inverter welding at sub-zero temperatures. Alas, this method of welding is not suitable for use in cold weather. Often, metal processing with an inverter is carried out at a temperature not lower than 15 degrees Celsius. In more severe cold, the device will not be able to provide high-quality welding.

Despite these disadvantages, the inverter can be called a reliable and high-performance device. The welding work carried out by him gives a high-quality and durable result. For this reason, inverter welding is suitable for high-quality processing of metal structures. Despite this, beginners are still advised to familiarize themselves in advance with how to weld metal with inverter welding.

Today, modern welding inverters are increasingly appearing in the home workshop, using which you can put a high-quality seam. Even a beginner can quickly learn the basics of how to properly weld by welding.

In this article, you will be able to analyze the questions that concern a novice welder. What basics of welding do you need to know and what may be needed? And also to understand the value of the current strength in this type of work.

At home, two types are used: transformer and inverter. What is the difference between them and what are the disadvantages and advantages in these types?

transformer

Based on the name, it can be understood that the principle of operation of such devices is built on a transformer. Electric current is supplied to the device and during operation its strength increases. The welding unit itself does not convert electricity and is powered by alternating current in the network.

This complicates the training and welding process for a beginner. In the network, the voltage is constantly jumping and in order to put a high-quality seam, the welder needs to control his movements and the arc in particular.

But the big advantage of such devices will be their unpretentiousness and survivability, as well as their low cost.

inverters

A welding inverter is much more complicated than a transformer. He transforms electricity from variable to constant. And again into the variable, increasing its frequency.

Welding training is better to start with such a device, it is more preferable. Additional features (such as anti-stick and hot start) allow you to quickly master arc ignition and seam guidance. At the same time, the addition in the form of synergistic control equalizes the electric current and the welder does not need to constantly control the distance of the electrode from the surface to be welded.

A comparison of the advantages and disadvantages of transformers and inverters can be seen in the table.

Based on the table, it can be understood that modern inverters are more suitable for a lesson on welding for beginners.

What electrodes to use

Often in home-made transformer units there is not enough power to use electrodes higher than the third number.

What a Newbie Needs to Know

The whole welding process can be carried out according to the following algorithm:

1. Preparation of the surface of the parts to be welded.
2. Connecting the welding machine and ground.
3. Arc ignition.
4. Welding.

It is worth knowing that there are three main types of welds:

• Horizontal. It is obtained by welding parts in a horizontal position. The simplest seam and it is worth starting training with it.
• Vertical. Details are arranged vertically.
• Ceiling. The most difficult of the options and it is worth practicing carefully before carrying out such welding work.

So, how to use the welding machine?

Training

Two parts must be well cleaned of dirt and rust. You also need to adjust the required size in advance.

Be sure to pay attention to clothing. Welding work is fraught with splashes and sparks. Best of all is a fireproof welder's suit, but in the absence of such, tight non-synthetic clothing and gloves can be used.

Be sure to have a good protective mask, a slag hammer, and goggles for your eyes.

Connection

Modern inverters work from a household network. To do this, simply insert the plug into the socket.

The mass cable must be fixed to one of the parts to be welded. The place where the clamp will be attached should preferably be cleaned from any contamination to metal.

The electrode must be inserted with the bare end into the holder. Be sure to set the current on the device. For cooking with a third electrode, the optimal figure is 70 amperes. But it may vary. Too much high strength current will cut metal, and low current does not contribute to the formation of a high-quality arc.

Ignition

In welding work, ignition of the arc can be done in two ways: by striking on the metal surface or by ordinary tapping.

When striking at the beginning of the weld, the end of the electrode must be carried out several times according to the principle of igniting a match.

Tapping with the tip is tapped at the point where welding will begin.

If the arc does not ignite, there is a good chance that the ground cable is not properly connected to the workpiece. Also, for quick ignition, you can clean the tip of the electrode from the coating with pliers.

With constant sticking, you need to increase the current strength, but without much fanaticism.

The convenience of electric welding is that the seam can be placed in various positions: away from you, towards you, from left to right. Depends on how comfortable.

But if welding occurs vertical parts, then the seam must be led from the bottom up.

After ignition of the arc, the electrode is led at an angle of 30-60 degrees to the surface. The distance depends on the weld pool formed during melting, usually 2-3 millimeters.

When moving the electrode, you need to control several parameters:

• Gradually lead the seam maintaining a distance from the surface to be welded.
• Monitor the weld pool and speed up or slow down the seam.
• It is necessary to move the electrode along an indirect path, but, for example, in the form of a "Christmas tree".
• Follow the direction of the weld.

For better seam guidance, it is best to first mark the place of welding with chalk.

When the process is completed, you need to knock down the slag and inspect the welding site for slagging of the seam or gaps.

What could be the mistakes

To understand how to use a welding machine correctly, you also need to know the main mistakes made when welding.

• If an uneven seam formed, then the movement of the electrode was too fast.
• In the case of the formation of burns (holes) in the metal, the speed of the seam was too slow.
• If the seam turned out to be flat and uneven, the angle of the electrode to the surface was incorrectly maintained (in this case, the angle of inclination was almost 90 degrees with the optimal 30-60).
• When, when knocking down the slag, it turned out that the metal was not welded, then in this case there was too small a gap between the electrode and the surface. Such a defect is formed from the "floating" of the seam.
• As in the previous version, if the gap is too large, the parts will also not boil through and the seam will be fragile.

The above is just the basics. They can be quickly mastered, especially using inverter devices for training.

They, having the functions of straightening and controlling the welding process, allow you to put a high-quality seam with minimal skills.

For welding thin-walled workpieces or profile pipes a more thorough approach is needed. Very thin parts can be welded by applying the electrode rod, cleaned of coating, and welding directly over it. But experience is needed here, since you can simply melt the metal on top of the parts and not provide sufficient fastening.

Welding work on aluminum or other non-ferrous metals and alloys requires the use of special electrodes. As a rule, such work is carried out using a protective medium (argon or carbon dioxide). Today you can buy universal welding machines with the ability to cook such materials.

Separate from the usual welding work, semi-automatic units are used for work with thin-walled parts. Here the connection process is due to the melting of a solid wire.

Also more complex are the vertical and ceiling seams.

For self-study, you can use videos and other materials. It is best to have welding lessons given by an experienced welder who will show different types seams.

Comments:

inverters are the best devices for welding. You should be aware that old transformers are heavy and difficult to use. Anyone can work with the inverter. To do this, you just need to know the basic principles of metal welding with this device.

The inverter welding machine has a small weight and high power, which allows even a novice welder to perform complex welding work.

First of all, the advantages of the inverter welding machine are its light weight and great capabilities. Thanks to this, with the help of this device, it is possible to perform work that was previously carried out only by complex devices. Electrical energy consumed by this machine small size, will be directed only to the work of the arc, with the help of which the welding process itself is carried out.

How to learn to weld metal, what you need to know before performing the welding process?

Correspondence table for electrode diameter and welding current.

The welding inverter is an economical machine that is convenient to use. With it, even beginners can learn how to weld metal. Before welding, it is important to learn about the principle of operation of this device. The inverter is an electronic welding machine, so the main load will fall on the mains. When old welding machines are connected to the mains, there is a strong and maximum possible push of electrical energy. As a result, the power grid of the entire region is being cut off. The inverter has storage capacitors that are capable of storing electrical energy, as a result of which uninterrupted operation of the electrical network can be ensured. The electric arc of the device in this case will be kindled gently.

You should know that the larger the diameter of the electrodes, the more electrical energy it uses. Therefore, if there is a desire to check the welding machine in operation, you will need to calculate how much electrical energy the device will approximately consume. This is necessary in order not to burn household appliances their neighbors.

For each of the electrode diameters, the minimum current is shown. Therefore, if you want to reduce the current, then the seam will not work. If you want to experiment and increase the current strength, then the seam can be made, but the electrode will burn out quickly enough, as a result of which the work will not be comfortable.

In order to be able to correctly install the metal blanks to be welded, clamps or a vice should be used.

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How to weld metal with an inverter?

First of all, you need to know what elements will be needed for protection when working with a welding inverter. You need to buy the following:

1. Leather gloves.
2. Helmet for protection.
3. Thick fabric jacket.
4. Metal brush.

You will need to adjust the welding current and select the electrode. In order to cook with a welding inverter, you will need to use electrodes from 2 to 6 mm. The welding current is set depending on the thickness of the elements of the apparatus and the material being welded. In most cases, there is information on the body of the device about how much current should be. No need to bring the electrode to the base for welding quickly. If this is done, sticking may occur.

The welding process must begin with the ignition of the arc. It is necessary to bring the electrode at a slight angle to the part that is being welded, and then touch the welding base several times so that it is possible to use the electrode for welding. The electrode is held by several elements from the workpiece that is being welded. In most cases, this distance is equal to the diameter of the existing electrode.

The result is a weld seam. Scale (metal scale in the upper part of the seam) is removed with a small hammer. You can use any other durable item that has a lot of weight.

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How to control the arc gap?

Figure 1. Arc gap suitable sizes will help form a good seam.

The arc gap is the gap that appears during welding between the metal workpiece and the electrode. It is important to continuously monitor and maintain the same value of this gap.

1. If there is a gap of small dimensions, then this can lead to the fact that the seam will be convex and not fused on the sides due to the fact that the main metal cannot warm up quickly.
2. If there is a large gap, then it will not be possible to weld the part, and the arc will jump. As a result, the metal that melts will fit crookedly.
3. It is important to provide a gap of the required size. This is necessary in order to be able to form a normal seam with good penetration. Visually, a gap of suitable dimensions can be seen in Fig. one.

If you learn to control the length of the arc, you will be able to get the best result. The arc will pass through the gap and melt the parent metal. The result is a weld pool. The arc will also be able to transfer the metal that is being melted into the bath.

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How to make a welding seam with an inverter correctly?

If the electrode moves quickly during welding, a defective weld will result. The bath line is located lower than the base of the main metal. If the arc penetrates quickly and deeply into the main metal, then it can push the bath back, resulting in a seam. During welding, it is necessary to ensure that the seam is located at the level of the metal. You can make a perfect seam if you use arc and zigzag movements. During the execution of circular movements, you will need to control the level of the seam, placing the bath evenly in a circle. In the process of movements in different directions, the same seam will be formed, therefore, it is necessary to control the appearance of the seam during welding, first of all from one edge, then in the upper part of the bath, and at the end on the other side, and so on.

The bath will follow the heat - this is important to remember when changing direction during the welding work. The formation of an undercut will occur when there is not enough metal of the electrode to completely fill the bath during transverse movements. In order to prevent the appearance of such a lateral groove, you will need to control the outer boundaries, regularly monitor the bathroom. If necessary, you can make it thinner. To manipulate the bath, you need to apply the force of the arc, which is located at the end of the electrode. In the process of tilting the electrode, the tub will push but not pull. Therefore, the more vertical the electrode takes during welding, the less convex the seam will be. When the electrode is placed in a vertical position, all the heat will be concentrated under it and the bath will be pressed down, melt well and spread around.

When the electrode tilts slightly, all the force will be directed back, causing the seam to rise (float).

When the electrode tilts too much during welding, the force will be applied in the direction of the seam, and this will not allow full control of the bath.

If you need to make a flat seam or move the bath back, you should use the electrode tilts at different angles.

Work should be started from 45° to 90°, because such angles make it possible to observe the bath and weld easily.

A welding inverter is a device that allows metal to be joined by welding. Compared to a rectifier or transformer, welding with an inverter is easier, simpler and more affordable. How to learn how to weld metal with an inverter?

Inverter welding: sequence of operations

Welding technology consists of a series of sequential steps. Them correct execution delivers quality results strong connection two metal surfaces. How to cook metal with an inverter, what to look for when learning to weld?

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Preparing for welding

1. Preparation of a place for welding. The space within a radius of a meter is freed from wooden, paper, plastic items. They can be ignited by a hot electrode or spark. The inverter is installed on the ground (concrete floor) and connected to the electrical network. Two mustaches (wires with terminals "+" and "-") are strengthened as follows: the plus terminal is attached to one of the metal surfaces to be welded, an electrode is inserted into the minus terminal (this connection is called direct polarity, it is the most common). The body of the welder is covered with protective clothing (trousers, jacket, gloves), a shield with dark glass (light filter) is put on the face.
2. We take in hand the terminal with the electrode. We turn on the inverter (toggle switch) - a small hum appears. We set the value of the welding current (with the regulator on the front panel). For a traditional electrode with a diameter of 3 mm, a welding current of 100 A is required. We lower the mask on the face (Fig. 1).

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Ignition of the arc at the beginning of welding

Figure 1. Dependence of the diameter on the thickness of the parts.

1. Let's start welding. In the beginning, you need to kindle an arc. With experience this will be easy. For a novice welder, ignition of the arc is the first difficulty. Before starting the ignition, the electrode is tapped on the metal surface to remove the coating from its end. To ignite the arc on cold metal (at the beginning of welding), the strike method is used. It is like lighting a match. The electrode is carried over the metal, slightly touching the surface of the part to be welded. For an inexperienced novice welder, the rod often sticks (sticks to the metal). To unstick it, it is necessary to sharply tilt the terminal with the electrode to the other side (break off the rod from the part). If it fails, turn off the inverter power. When the current is turned off, the sticking will disappear.
2. We strike until an electric arc is formed. It is very bright, you can only look at it through a light filter.
3. To maintain the arc, we fix the end of the electrode 3-5 mm from the metal. At the beginning of training, it will be difficult to maintain the required distance. If the electrode is too close, a short circuit will occur and it will stick to the part. If removed, the arc will be lost and will need to be re-ignited. During the welding process, the electrode is consumed, its coating burns out, and the base metal fills the seam between the surfaces to be welded. Therefore, the hand with the terminal gradually lowers down.

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Weld pool and weld

Figure 2. Dependence of the diameter on the thickness of the parts.

1. When the arc is ignited, a liquid puddle of molten metal is formed. This is a welded tub. To connect metal parts over the entire contact surface, the electrode slowly moves along the interface. Behind him moves the weld pool (liquid metal zone). The end of the rod oscillates (back and forth, left and right) relative to the seam between the two parts. This ensures the quality of the connection.
2. If the arc has been lost (the electrode is too far away from the weld), re-ignition is easier. To ignite the arc, it is enough to bring the end of the rod closer to a distance of several millimeters.
3. A bright electric arc and a less bright weld pool are clearly visible in the welded shield. The contact surfaces to be welded in the welding zone are less distinguishable. However, it is impossible to remove the shield and peep at welding without a protective light filter. At best, the eyelids will itch unpleasantly (feeling of sand in the eyes). At worst, you can lose your sight without the possibility of restoring it.
4. When the rod is shortened to 5-6 cm, welding is stopped, the inverter is turned off and the electrode in the terminal is changed.
5. At the end of welding, the frozen seam of metal is tapped with a hammer to remove the slag layer. The seam cleared of slag has a brilliant surface.

This is the technology of welding with an inverter as a whole. And now let's dwell in more detail on how to choose the right electrode and welding current.

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What electrodes to weld metal?

The electrode is a metal rod coated on the outside with a coating. The coating substance is a slag mixture, which also melts during welding, rises to the surface of the weld pool (it is lighter than metal) and protects the liquid metal from oxidation and saturation with nitrogen (Fig. 2). In some cases, gas-forming additives are introduced into the composition of the coating, which ensure the release of gas during the melting of the electrode.

The composition of the inner rod is determined by the type of metals being welded (low-carbon and low-alloy steels, brass and bronze, magnesium alloys, titanium alloys). To weld ordinary metal carbon steel, UONII brand electrodes are used. They are also used for corrosion resistant steels. UONII welding is performed only by direct current.

ANO marking rods are considered more universal. They are suitable for both forward and reverse current of any polarity.

The electrodes differ not only in the composition of the coating and the rod, but also in diameter. The dimensions of the rod in the coating vary from 1.6 mm to 5 mm in diameter. The thicker the parts to be welded, the larger the diameter of the electrode required for their fusion. There are mathematical formulas for calculating the diameter for a given thickness of metal parts. It is easier for a novice welder to use tables.

Secondary factors affecting are the type of connection of parts (horizontal, vertical or overhanging welding, butt or fillet weld). From the data in the table it can be seen that the diameter of the electrode for corner connection slightly different from the diameter for butt welding parts.

At the same time, welding rods are not used for welding overhanging surfaces. large diameter. For the ceiling, their dimensions are limited to a diameter of 4 mm.

Varying the diameter of the rod while maintaining all other parameters can increase or decrease the specific welding current (current per unit section of the electrode). This will affect the depth of penetration and the thickness of the weld. If the electrode is thinner, the current strength is concentrated and melts deeper, the weld is narrow. If the electrode is thicker, the specific current strength decreases, and the penetration depth becomes smaller, and the weld width becomes larger.

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How to choose the value of the welding current and its polarity?

The strength of the current determines the depth of penetration of the metal. The stronger the current, the more powerful the arc, the deeper the metal melts. The current strength is directly proportional to the diameter of the electrode and the thickness of the weld. It can be determined by calculations using formulas or use ready-made tables.

The current strength is affected by the location of the weld. The maximum current value is used to penetrate horizontal surfaces. In order to weld vertical seams, the current strength is 15% less, for overhanging (ceiling) joints - 20% less.

The household inverter has a current scale up to 200 A. In semi-professional models, the scale value is graduated higher, up to 250 A.

Figure 3. Movement of the electrode during welding.

Polarity is the direction of current flow. The inverter makes it possible to change the direction of the current. How is this done and why is the polarity reversal necessary?

The flow of electrons (the current moves from minus to plus) in welding with an inverter moves from the “-” terminal to the “+” terminal. The terminal to which the electrons ("+") come, warms up more. This fact is used to ensure high-quality welding on various metals, with various thicknesses of elements. If the parts are massive, then the “+” terminal is attached to their metal surface (to one of the parts). This connection is called direct polarity, it is more often used in welding work.

If fused thin sheet steel or a high-alloy alloy, prone to burnout of alloying elements, then the “-” terminal is connected to them. The resulting polarity is called reversed. With such a current flow, the maximum heating occurs in the electrode, and the base metal heats up less.

Reverse polarity is characterized by greater arc stability, it is easier to ignite and maintain its combustion.

Welding inverters (with their low price in 7-10 thousand) forms high-quality seams, even if they are in the hands of beginners. Of course, the work will turn out good if you follow simple rules. All of them are described in the article. However, before work, beginners need to read the instructions for the device. There are usually several useful tips as well as safety precautions. Remember that everyone can learn to weld metal.

How a welding inverter works

Welding inverter - a tool for welding metal. It got its name because it transforms alternating current into permanent. And although the inverter efficiency is about 90%, its power consumption is low, so you don’t have to worry about high electricity bills.

Most often, the welding inverter runs on 220 volts, some types - from 380. At the same time, it is possible to work at reduced voltage: a 3 mm electrode, for example, can be used at 170 volts.

It is much easier to weld with an inverter than with a transformer or rectifier. In addition, even a beginner can hold the arc. That is why most people learn the art of welding on it.

Preparation for work

What electrodes to use

The electrode is a rod made of metal, which is coated with a special coating - a slag mixture. Gas-forming substances are sometimes added to it. Coating will protect the molten metal from oxidation.

The rod is selected depending on the type of metal to be welded. For example, to work with carbon or stainless steel, you will need the UONII electrode grade. There are also universal electrodes. These include the ANO brand. They are used for reverse and forward current of any polarity.

The electrodes are also divided by diameter, which varies from 1.6 mm to 5 mm. The size is selected depending on the thickness of the metal being welded: the larger it is, the larger the diameter. A table may come in handy when working with a welding machine.

The thicker the rod, the more power the inverter welding machine must have. Therefore, for beginners, a diameter of no more than 4 mm is suitable; thin metal can be welded with an electrode and in 2 mm.

Polarity and value of welding current

The thickness to which the metal can be melted directly depends on the set current strength. The arc power is also determined by this indicator. The size of the electrode determines the required current strength.

Depending on the surface, the value of the welding current is selected. On horizontal surfaces it is maximum, on vertical surfaces it is less by about 15%, on overhanging surfaces it is 20%.

A household type welding machine can deliver up to 200 amperes. On a professional instrument, the values ​​\u200b\u200breach up to 250 and above. The direction in which the current flows will determine the polarity. On the inverter, it is possible to change the polarity.

As you know, the current moves from minus to plus. Therefore, the "+" terminal heats up more. This feature allows for high-quality metal welding. In the event that the parts to be welded are thick, then the positive terminal is connected to one of the parts. This method is called direct polarity.

A negative terminal is attached to thin products. This method connection is called reverse polarity.

Welding instruction

Welding basics

Before proceeding directly to the welding of metal products, you need to study the main design features of the inverter welding machine. They are shown in the diagram.

The inverter itself has an average weight: up to 7-8 kg. At quality tool on the side of the metal case there is a ventilation grill that prevents the transformer from overheating.

There is an on/off button on the back panel. On the front there are two connectors: "+" and "-". A cable is connected to them, at one end of which there is an electrode, and at the other - a clamp. The cables themselves must be of sufficient length and flexible.

Step by step instructions on how to cook with an inverter.

1. Inverter welding begins with the preparation of protective equipment. At your disposal is a welding mask, a thick jacket, rough but not rubber gloves.
2. Select an electrode. If you are a beginner, then do not use a rod thicker than 4 mm. On the front panel, adjust the desired amperage. Wait a little; If you bring the electrode directly to the metal, sticking will occur.
3. We fasten the clamp (it is also called the mass terminal) to the metal surface.
4. The arc is ignited. Then we bring the electrode to the metal and touch it a couple of times. Thus, the rod is, as it were, “activated”. The distance at which the electrode is held is usually equal to its diameter.
5. The rod during welding can move according to such schemes.

Arc ignition at the beginning of welding + (Video)

Striking the arc is the first step, and beginners have problems with it. First, the rod is tapped a little on the metal so that the grease is removed from it. Then a method similar to lighting a match is applied. The electrode is led over the surface of the product and slightly touches it. If suddenly the rod sticks to the metal, it is either sharply removed from the side, or the inverter is completely turned off.

You need to strike until a bright arc appears. To prevent the arc from disappearing, keep the electrode at a distance of 4 mm from the metal.

How to move the electrode during welding + (Video)

The electrode can only move along certain trajectories. They have already been shown. If you move the electrode only straight, the seam will come out discontinuous. The speed of its movement affects the properties of the seam. If you move quickly, the seam will be narrow and not convex, if slowly - wide and convex. In the place where the seam will end, the electrode is delayed for 3-4 seconds.

How to form a weld and avoid defects + (Video)

An uneven seam, most often, is formed when the electrode moves too fast. Speaking about creating an even and high-quality seam, you need to introduce the concept of a weld pool. The weld pool is that part of the metal that is in a liquid state during welding. Filler material enters this part. The appearance of a pool is a good sign that the welding is proceeding correctly.

The tub contour is below the surface metal part. The bath forms a good seam if the welding arc passes evenly and to a great depth into the workpiece. It is necessary to ensure that the seam does not go down, but remains at the surface level. A good connection is easier to create if the electrode is moved in a circular motion. In this case, the bath should be distributed in a circle.

When seaming corners, remember that the tub moves with heat. Adjust the force of the arc to control the dimensions of the tubs.

The seam will not be too convex if you keep the electrode close to the vertical position. If you tilt the rod (for example, by 45˚), then the seam will begin to emerge. And when the electrode is very close to the horizontal position, the bath begins to diverge, and the seam is bent. Therefore, the optimal tilt angles are from 45˚ to 90˚.

Arc gap control

The arc gap is the distance between the metal surface and the electrode. The gap at each stage must be the same so that the welding is of high quality and without defects.

If the gap is small, then the weld will turn out to be too convex, and the material itself will not fuse well. This happens because the product cannot heat up. With a large gap, the welding arc will move from side to side, and the seam will come out crooked and fragile. The correct gap shown in the figure will give good penetration and a smooth seam.

How to weld thin metal sheets + (Video)

For welding thin metal, it is preferable to use the reverse connection of the inverter, i.e. "-" is attached to the sheet. In this case, the current strength should be at medium values. It is better to choose an electrode that will have long time melting. The MT-2 model is well suited. It has been used by welders for a long time, so it has proven itself well.

The rod, in the case of thin metal, can be tilted by about 35˚. First, you carefully bring it closer to the metal, then wait for a red spot to appear, turning into a drop. Gently move the electrode so that the drop remains the same size. So the seam will be even.