Profession: “Electric welder of manual arc welding” Electric welder

Welding is used in almost all industries. It is difficult to name any segment of production that does not require the work of a welder. As a profession for beginners, it provides the opportunity to obtain promising work. Welders work on construction sites, creating systems of various communications and structures, in industry, applying their skills and experience, in shipbuilding, mechanical engineering, energy, agriculture, oil refining industry.

First of all, the welder must be fluent in welding equipment. At the same time, he, as a specialist, is required to have a thorough knowledge of the principles of its operation, preparing equipment for operation and identifying possible malfunctions. The welder must be proficient in the technology of welding work from preparing the surfaces to be joined to cleaning weld and detection.

A specialist performing welding work must know how to properly weld with electric welding and determine the optimal mode for welding various materials, set the current value. The complexity of the work of a gas-electric welder also lies in the fact that during the welding process, changing the welding mode can negatively affect their quality, therefore it is extremely important to correctly determine the welding speed from the very beginning. Qualified welders perform manual arc welding and can create quite complex metal structures and pipelines. The welder must know how to handle different types metals: alloys, steels (including those with limited weldability).

How to learn to cook with electric welding

Welding professions are taught in colleges, vocational schools, and courses. Training is carried out for three years on the basis of ninth grades and two years on the basis of eleventh grades.

If you are not going to work as a welder, but want to learn how to learn how to work with electric welding so that, if necessary, you can weld something yourself, you can use the advice in this article, or the literature from the “Electric welding tutorial” series. Of course, in this case you will not become a top-class welder, but this is not required. The main thing is to understand how to use electric welding correctly, learn the basics of electric welding, and learn basic work techniques.

Basics of electric welding

First of all, you need to purchase welding machine and electrodes, which you need to stock up on in decent quantities, since during the learning process, you will have to ruin a lot of them before you achieve the first positive result. Choose electrodes for welding with your own hands with a diameter of 3 mm. They are the most suitable for training at home, since the thinner ones are suitable for very thin metal, which only experienced welders can weld, while the thicker ones place a heavy load on the electrical network.

DIY electric welding

For beginners, this is not an easy task, but it is quite doable, although it requires a lot of perseverance. You just need to practice more. And the learning process is best carried out under the supervision of professionals who can help with advice and correct mistakes.

To understand how to weld metal correctly, use some unnecessary piece of metal. Place a bucket of water nearby in advance. Under no circumstances should you perform work on wooden workbench. Be careful as even small remnants of a used electrode can cause a fire.

Securely attach the "ground" clamp to the part. The cable must be well insulated and tucked into the holder. After this, you can set the current power value on the welding machine. It must match the diameter of the electrode.

Spatial positions of the weld

Now you can try to light the arc. To do this, install the electrode at an angle of about 60 degrees relative to the workpiece. Run the electrode very slowly across the surface. After sparks appear, touch the workpiece with the electrode and lift it so that the gap does not exceed 5 millimeters. If everything is done correctly, the arc will light. This gap must be maintained throughout the entire operation. Please note that the electrode will burn out. It must be moved slowly. If the electrode gets stuck, swing it to the side. If an arc 2 - 3 millimeters long does not ignite, then it is necessary to increase the current strength by . Try to get a stable arc 3 - 5 millimeters long between the part and the end of the electrode.

If you succeeded in igniting and maintaining the arc, then you can try fusing the bead. To do this, you need to light the arc and smoothly move the electrode horizontally, while performing oscillatory movements (see below for more details). “Rake” the molten metal towards the center of the arc. The result should be a beautiful seam with small waves of deposited metal.

To form and hold an electric arc, welding current (direct or alternating) is supplied to the workpiece and the electrode from the power source.

Electrode movement diagram

When connecting the positive pole of the power source (anode) to the product, manual arc welding straight polarity. If the negative pole is connected to the product, then reverse polarity welding is performed. Under the action of an arc, the metal rod of the electrode (the so-called electrode metal), its coating and the material of the product (base metal) are melted. The electrode metal, now in the form of individual droplets coated with slag, enters the weld pool, in which it is mixed with the base metal, with the molten slag coming to the surface.

The size of the weld pool depends on the spatial position and welding modes, design welded joint, the speed of movement of the arc on the surface of the product, the size and shape of the cutting of the edges being joined, etc. It usually varies within the following limits: width 8 - 15 mm, depth up to 6 mm, length 10 - 30 mm.

The arc length is the distance from one active spot on the surface of the weld pool to another on the molten surface of the electrode. When the electrode coating melts above the weld pool and near the arc, a gas atmosphere is formed, displacing air from the welding zone and preventing its interaction with the molten metal. It also contains pairs of alloying elements of the electrode and base metals.

Covering the surface of the weld pool and drops of molten electrode metal, the slag prevents their interaction with atmospheric air and helps clean the molten metal from impurities.

With the gradual removal of the arc, the metal in the weld pool crystallizes, forming a seam connecting the parts being welded. A layer of frozen slag forms on its surface.

Manual arc welding technique

The key to quality welding is the correct maintenance and movement of the electric arc. If the arc is too long, oxidation and nitriding of the molten metal occurs, splashing its droplets and creating a porous structure of the weld.

An even, beautiful and high-quality seam is obtained only when correct size arc and its uniform movement. It can occur in three main directions.

Welding with electrode support

As a result, all three movements, overlapping each other, create a rather complex trajectory of the electrode. In practice, everyone experienced craftsman have their own skills in choosing the trajectory of the electrode. The classic trajectories of electrode movement performed during manual arc welding are presented in the figures below. But in any case, the trajectory of the arc must be chosen so that the edges of the parts to be connected are melted, forming required quantity deposited metal and the specified weld shape.

Bottom layered seams

During the process of electric arc welding of metals, the electrode can burn out almost completely - only a small piece of the rod remains in the holder clamp. If the seam cannot be completed by this point, welding should be temporarily stopped. After replacing the electrode, it is necessary to remove the slag and resume welding again.

Electrode movement pattern when making vertical seams

To complete a broken seam, the arc is struck at a distance of 12 millimeters from the depression that has formed at the end of the seam, called a crater. To do this, the electrode is returned to the crater in order to form an alloy of the new and old electrodes, and then they begin to move it again along the originally chosen trajectory.

Horizontal seam on a vertical plane

Advantages of manual arc welding:

• the ability to perform work in places with limited access;
• welding capability various types steels due to a very wide selection of manufactured electrode types;
• the possibility of a relatively quick transition from one joined material to another;

• possibility of welding from any spatial position;
• simplicity and fairly easy transportability of welding equipment.

The disadvantages of electric arc welding of metals include:

• harmful conditions welding process;
• low productivity and efficiency compared to others

To be able to carry out work at any time in a home workshop or on personal plot work related to connecting elements metal structures, it is enough to purchase a modern welding machine and learn how to weld with a welding inverter.

Welding work has long been widespread not only in serious production, but also in everyday life.

Design and advantages of inverter welding machines

The great popularity of inverter equipment among home craftsmen is explained by the fact that with the help of such compact devices, which are also lightweight, it is possible to make high-quality, reliable and accurate welded joints, even without high qualifications.

Any design welding inverter consists of such elements as:

• power supply with rectifier unit and filter;
• inverter unit that converts direct current into high-frequency alternating current;
• transformer for reducing the voltage of high-frequency current;
• power rectifier designed to produce direct current at the output of the device;
• an electronic unit that performs device control functions.

Innovative technologies implemented in the design of inverters make it possible to obtain high-quality welded joints without any problems. Due to their compactness, such devices do not take up much space, and thanks to light weight(5–15 kg) without them special labor can be moved anywhere.

If you learn how to work correctly, you can use it to weld any metal structures. Each new inverter comes with instructions, from which the owner of the equipment can glean a lot of useful information: how to properly connect the device, which electrode to choose in order to weld products from a particular metal, etc.

Patterns of electrode movement depending on the type of seam (click to enlarge)

However, often in the hands home handyman an inverter device is received, the instructions for which are not translated into Russian or are missing altogether. It is very important to learn correctly, because if you act at random it will be difficult to weld metal well. In addition, you may encounter equipment failure.

However, if you follow generally accepted rules, you can work on any model of inverter and effectively solve all the tasks. After carefully studying these rules, watch the training video, which will help reinforce the theoretical material with visuals.

How to prepare equipment for operation

Before you start welding metal, prepare all the necessary equipment to ensure your safety: a welding helmet, special clothes made of thick fabric, work shoes and gloves, which should also be made of thick material.

In order for the weld to be of high quality, it is necessary to select the correct electrodes. Their type and diameter are selected depending on the metal from which the parts being joined are made, the thickness of the latter, as well as the welding modes. Since the surfaces of the workpieces to be welded must be thoroughly cleaned, you also need to prepare a brush with metal wire bristles.

Before connecting the inverter to electrical network, you need to check whether the network parameters match the characteristics of the connected equipment.

These parameters include strength electric current and the voltage value, which must be within the range specified in the inverter passport. The device should be connected to the power supply through an automatic circuit breaker, which will prevent equipment breakdown if a short circuit occurs in its electrical circuit or the voltage increases sharply for another reason.

Before starting welding, it is necessary to take care of the condition of the working site. The inverter should be installed on flat surface, and there must be enough space around its body to ensure free movement of air, due to which natural ventilation devices. Do not cover the device body with fabric, which will restrict the flow of air to its ventilation grilles.

The welding process is accompanied by high temperatures and splashing of molten metal, so there should be no flammable, fire or explosive substances on the work site.

After all preparatory activities have been completed and safety requirements have been met, you can proceed to the following actions:

• connection power cable and ground cable to the corresponding connectors of the inverter;
• fixing the mass cable on the parts to be welded (for this, use special clamp);
• connecting the device to the power supply and setting welding operating modes on it;
• fixing the electrode in the welding holder.

The sequence and correctness of performing such actions is well demonstrated by the training video. Now that the inverter is connected to the electrical network and the electrode in its holder is ready for use, you can begin welding.

Features of welding work using inverter devices

The first thing you need to do to start cooking with an inverter is to light an electric arc between the surface of the part and the tip of the electrode. To do this, the latter makes a scratching movement along the surface of the workpiece, as a result of which a bright flash should appear. The metal in the arc zone will begin to melt. You can learn how to light an arc correctly and do it quickly by watching a training video.

When performing welding, it is important to monitor the length of the arc, which should approximately correspond to the diameter of the electrode used (in this case, the parts will be evenly melted, which will allow the formation of a high-quality weld). It is necessary to ensure that such penetration occurs evenly throughout the entire welding process.

The quality and reliability of the weld is also influenced by the polarity of connecting the inverter power cable and the ground cable. To choose this polarity correctly, you need to know exactly what material the parts being connected are made of. Most grades of steel and other metals are best welded with direct polarity; only some alloys are combined with reverse polarity.

The design of modern welding inverters ensures smooth and efficient regulation of the operating current, which makes working with such devices simple and comfortable even for novice welders. You can judge that the welding current is selected incorrectly based on a number of factors. So, if it is too small, then the weld seam turns out to be too convex and narrow, and the parts in such cases are poorly fused. If the current is too high, then intense spattering of molten metal occurs, and burns may appear on the surface of the parts being connected.

Depends on the choice of strength welding current and on what diameter electrode you are going to cook with. Thus, when welding metal from one to three millimeters thick with electrodes with a diameter of up to 1.5 mm, the welding current is selected in the range of 20–60 A. In the event that rods are used larger diameter, which can be used to weld metal 4–5 mm thick, the welding current is selected within 100 A.

While watching a training video or watching the work of a qualified specialist, novice welders are often interested in why slag is knocked off the surface of the finished weld. This is done in order, firstly, to check the quality of the weld, and secondly, to give the finished joint an attractive appearance. A seam cleared of slag shows all the mistakes made during welding.

Of course, you should not expect that novice welders (or so-called dummies) will immediately produce beautiful and high-quality welds. Mastery, including in welding, does not come immediately after familiarizing yourself with theoretical material and watching videos; it is developed only through experience.

How to choose the right welding inverter and electrodes for it

Correctly selected electrodes play a big role in the formation of a high-quality and reliable welded joint. It is impossible to learn how to choose them from a video; to do this, you should adhere to generally accepted recommendations and the following principles.

• When working with medium and low carbon steels, carbon electrodes are used.
• Alloy steels are welded using electrodes produced in accordance with GOST 10052-75 and 9466-75.
• For welding cast iron products, OZCh-2 grade products are used.

Classification of electrodes by type and purpose (click to enlarge)

In a private house, country house or garage, quite often there is a need to connect various metal parts and create structures from them. It makes no sense to turn to professionals for help every time in such a situation, because you can purchase an automatic welding machine yourself.

A wide range of different devices are available in stores in different price categories, so welding with an inverter for beginners is the best that the market has to offer.

Inverter devices are characterized by fairly high efficiency and ease of operation. The main load for the operation of such equipment falls on the electrical network.

It has storage capacitors that allow you to accumulate electricity and ensure an uninterrupted welding process and soft ignition of the arc.

Unlike old devices, which provide a maximum boost of electricity for work, which can result in traffic jams, an inverter allows you to safely operate from a household power supply.

Defects in welds.

To figure out how to cook inverter welding, you need to understand the basics of its work.

In similar devices manual welding the arc is formed as a result of contact of the electrode with the product. Under the influence of temperature, the metal and electrode melt. The molten part of the rod and the product form a bath.

The rod coating also partially melts, turning into gaseous state and closing the weld pool from oxygen. This allows you to protect the product from oxidation.

Each electrode, depending on its diameter, is designed for a certain current strength. If you reduce it below the required value, then the seam will not work. Increasing this parameter will allow you to form a seam, but the rod will burn out too quickly.

At the end of the welding work, the coating cools down, turning into slag. It covers the connection of metal parts with outside. By tapping the seam with a hammer, it is quite easy to get rid of the slag.

There is also simple rules welding To ensure that the arc does not go out during work, the welder should maintain a constant distance between the rod and the workpiece.

This is not easy to do because the electrode melts, so it must be fed into the welding zone at a constant speed. In addition, you must try to guide the electrode evenly along the joint in order to obtain a seam of maximum quality.

Welding methods

Nowadays there are many methods used for welding. They are divided according to various criteria. This information will be useful for a beginner, so you should definitely read it.

Depending on the heating, the edges of the product may completely melt or be in a plastic state. The first method also requires applying certain forces to the parts being joined - pressure welding.

In the second, the connection is formed as a result of the formation of a weld pool in which there is molten metal and an electrode.

There are other welding methods in which the product does not heat up at all - cold welding, or are not brought to a plastic state - connection using ultrasound.

Methods and types of welding.

Other types of welding are listed below:

1. Forge.
   IN this method the ends of the joined products are heated in a forge and then forged. This method is one of the most ancient and is currently practically not used.
2. Gas press.
   The edges of the products are heated with oxygen acetylene over the entire plane and brought to a plastic state, after which they are subjected to compression. Similar method is different high efficiency and productivity. Used in the construction of gas pipelines, railway, mechanical engineering.
3. Contact.
   The parts are included in the electrical circuit of the welding equipment and current is passed through them. A short circuit occurs at the point of contact of the parts, as a result of which large number warmth. It is enough to melt and join metal.
4. Butt, point and suture are varieties of the contact method of fastening the product.
5. Roller.
   Used in joining sheet structures that require high-quality and reliable seams.
6. Termite.
   The metal is held together by burning thermite, a mixture of iron oxide powder and pure aluminum.
7. Nuclear-water.
   The edges of the product are melted by the action of an arc burning between two tungsten electrodes. The electrodes are connected to special holders through which hydrogen is supplied. As a result, the arc and liquid metal of the weld pool are protected by hydrogen from the harmful effects of such atmospheric gases like oxygen and nitrogen.
8. Gas.
   The essence of the method is to use a flame to heat and melt parts. A flame is produced by burning a flammable gas in an oxygen atmosphere. The gas-oxygen mixture is produced using special burners.

Under the action of an atomic-hydrogen welding arc, hydrogen molecules are split into atoms and then recombined upon contact with cold metal. As a result of this process, a large amount of heat is released. The method is used for welding metals of small thickness, copper and alloys based on it.

The gas welding method refers to fusion welding. The gaps between the products are filled using filler wire. This method is widely used in various areas human life. Most often found when joining thin-walled products, non-ferrous metals, cast iron.

When working with an inverter device, the polarity of the electrodes is of no small importance. Depending on the circuit, the heating intensity of the part changes, which allows you to create various conditions welding

Step-by-step instructions for welding with an inverter

First of all, for welding you need to have protective elements:

• gloves made of rough fabric;
• welding mask with a special filter protecting the eyes;
• a rough jacket and trousers made of material that will not catch fire from sparks that appear during welding;
• closed shoes with thick soles.

Electrode position during welding.

Before you start welding with a welding inverter, you must take the necessary measures aimed at creating safe working conditions.

Proper preparation of the workplace consists of:

• providing the necessary things on the table free space, you should remove all unnecessary objects that could get splashed;
• creating high-quality lighting;
• Welding work must be performed standing on wooden flooring, protecting against electric shock.

Then the current is adjusted depending on the thickness of the parts and the electrodes are selected. The latter need to be prepared. If they were only purchased in trading network and their quality is beyond doubt, then this step can be skipped.

If the rods have been in an unheated, damp room for a long time, then they need to be dried for two to three hours at a temperature of 2000 degrees. For these purposes, you can use an old oven or special equipment, if any.

After preparing the electrodes, the ground terminal is connected to the product.

To obtain a high-quality and reliable connection, the metal must be prepared:

• rust is completely removed from the edges of the product;
• using solvents, various contaminants are cleaned;
• on last stage The edges are checked for cleanliness; the presence of grease, paint and other contaminants is unacceptable.

Next you need to connect the welding inverter. Training is best done on a thick metal sheet, forming a seam in the form of a roller. Make the first connection on metal lying horizontally on the table. Draw a straight line on it with chalk along which the seam will go.

Electrical circuit of the inverter.

In the process of training on such an object, you can significantly improve your welding technique.

The welding process begins with ignition of the arc.

There are two ways to perform this action:

• scratching on metal;
• tapping on metal.

The choice of method depends on the person’s preferences; the main thing when igniting is not to leave traces of welding outside the joint area.

After the arc is ignited from contact with the metal, the arc is ignited, the welder withdraws the electrode from the surface of the part to short distance, corresponding to the arc length and starts welding.

As a result, a weld is formed at the junction of two metal parts. It will be covered with scale - scale on the surface. It needs to be removed. This is very easy to do by tapping the seam with a small hammer.

Forward and reverse polarity

Melting of the metal for welding occurs under the influence of an arc. It, as noted above, is formed between the surface of the product and the electrode, since they are connected to opposite terminals of the device.

There are two main options for welding, differing from each other in the order of connection and called direct and reverse polarity.

In the first case, the rod is connected to the minus, and the part to the plus. In this case, an increased flow of heat occurs into the metal. As a result, a deep and narrow melting zone is formed.

Direct and reverse polarity.

With reverse polarity, the electrode is connected to the positive, and the product to the negative. In this case, the melting zone is wide and shallow.

The choice of polarity is entirely determined by the product you are working with. Welding can be performed with two types of polarity. When choosing, you should take into account the fact that the element connected to the positive is subject to greater heating.

For example, it is difficult to weld thin metal products due to possible overheating and burning. In this case, the part is connected to the minus. Currents are also selected according to the diameter of the electrode and the thickness of the metal. This data is taken from a special table.

Effect of electrode feed speed

The feed rate of the welding electrodes must provide the required amount of molten material supplied. Not having enough of it can lead to undercutting. This factor is very important in both direct and reverse polarity when welding.

During electric arc welding, due to the rapid movement of the rod along the joint, the arc power may not be enough to heat the metal. The result is a shallow seam that lies on top of the metal. The edges remain unmelted.

Slow advance of the electrode leads to overheating. In this case, it is possible to burn the surface and deform the thin metal.

Modern welding machines have a wide range of different functions and capabilities. Nevertheless, at the moment, most of the quality work done is still determined by human skill.

Effect of current

Welding current selection table.

When mastering the basics of welding with an inverter, it is important to understand what current strength needs to be set in each individual situation. A properly configured inverter welding machine is the key to success.

Data on the current value are taken from the table, which also shows the size of the electrodes. However, these current values ​​are not exact; they are plus or minus several tens of amperes.

Features of welding thin metal

In everyday tasks, we are most often faced with the need to join thin metal. IN in this case It is necessary to remember the basics of inverter welding for beginners, namely the importance of connecting the product to the correct pole. Thin parts are connected to the “minus” of the welding machine.

To learn how to weld correctly and get beautiful seams, you need to practice.

Here are a few useful tips who can improve their skills:

• start cooking using the minimum current;
• form the seam at an angle forward;
• use reverse polarity;
• secure the part to reduce distortion during welding.

Common mistakes made by newbies

Arc welding diagram.

Beginner welders tend to make mistakes due to ignorance of the basics regarding the use of welding equipment. For example, beginners may not know how to choose the correct polarity for welding with an inverter, which will lead to poor-quality joint formation or even burning of the part.

The following main errors can be identified:

• neglect of safety precautions;
• incorrect choice of welding machine;
• use of low-quality or unprepared electrodes;
• work without trial seams.

For beginners, it is worth separately noting one feature if you cook Resanta by welding. This equipment is very popular, but it has short connection cables, which can create inconvenience in operation.

Let's sum it up

Having learned to work with welding equipment, it will be possible to solve many everyday problems that often arise when working in the country or in the garage. Beginners should special attention Pay attention to the polarity of welding parts of different thicknesses with an inverter.

By understanding how to properly configure the equipment and choose an electrode, you will be able to obtain high-quality seams on any product. Be sure to pay attention to the forward and reverse polarity of connecting the welding inverter.

When welding thick parts, direct polarity is used when welding with an inverter, and for thin parts, reverse polarity is used.

Now many people want to learn the basics of welding. This can always be useful in everyday life. Welding for beginners does not require professional skills and special knowledge. This level is sufficient for work in a garage or farmstead.

When learning the basics of welding, you need to use electrodes with a diameter of no more than 3 mm.

Basics and basic concepts about electric welding

First of all, in order to master manual welding, you should purchase a welding machine and stock up on electrodes. There should be as many of them as possible, since they will often spoil until the first positive result is obtained. When learning the basics of welding, it is better to use electrodes with a diameter of 3 mm. Thinner ones are used by specialists to work with thin metal, while thicker ones overload the electrical network.

The universal and simplest type of joining metal surfaces is the manual arc welding method. It consists in the transfer of electric current from a source with the formation of an arc between the electrode and the material being processed. With this welding technology, the combustion of the coating on the surface of the electrode ensures the release of gas, which prevents the treated area from coming into contact with oxygen from the air.

Any welding manual states: the first thing you should learn is the correct welding seam. Therefore, the introduction contains information about the equipment used. Among the power sources, the following designs are distinguished:

• welding transformers;
• welding rectifiers;
• welding inverters.

For those learning the basics of welding, the third option is optimal choice. You can weld metal semi-automatically. Welding wire is often used for this.

After you have purchased the equipment, you must first provide yourself with protection from harmful effects. Safety precautions when welding require a special mask that protects the skin of the face and eyes, with a built-in light filter selected in accordance with certain criteria. These include amperage, ambient lighting, and the welder's vision. The welding procedure implies strict adherence to safety rules.

In order to use welding, you should choose a canvas apron or a suit with fire-resistant impregnation from workwear, as well as split leather leggings. Shoes must be durable and stable.

Return to contents

During welding, the electrode must be held above the surface of the metal. The resulting gap is called an arc gap. Control over it is especially important when working, so it should be mastered first. The electrode is lowered because it is consumed moving towards the seam. Always keep the gap between the metal and the edge of the working tool at the same level. You need to cook with electrodes carefully so as not to spoil the consumables.

Features:

1. If the gap size is insufficient, there will not be enough time to warm up the material being processed. The seam will be convex and the edges will not be fused.
2. With a larger gap, significant arc jumps are observed. The quality of the penetration will be poor, and the management of the laying of the metal that is being welded will be difficult.
3. By keeping the optimal gap size at a constant level, you can easily control the bathtub and form a good seam.

Current welding technology is as follows: while passing through the gap, the arc creates a weld pool, transferring into it the molten metal located on the surface of the electrode. If the current value is insufficient, the base metal will not warm up, and the electrode will move faster than the weld pool. With a higher current, the arc will penetrate the metal to a certain depth, pushing it back. When the values ​​are optimal, the bath spreads and has thin edges, so it can be expanded and moved using an electrode, controlling the work process.

Current settings often change depending on welding technology and additional options. For example, the heat dissipation properties of thick metal will require a higher current value. For smaller thicknesses you need a different one high level. The exact setting of the current indicators in order to cook correctly will depend only on how the bath behaves. Therefore, you need to start with the manufacturer’s recommendations, and then experiment with decreasing or increasing the current.

When finishing the seam, before removing the electrode, you need to make a little more metal deposition.

This will help avoid a splash from lower layers seam, which will cause a crater. To do this, just make one circle, and then strike in the opposite direction of the seam.

Return to contents

Manual arc welding: features of the technological process

The flow of both direct and alternating current from the power source in the direction of the electrode and the metal ensures the formation of an arc and holds it. This type of manual welding with straight polarity is performed when connecting the anode to the product. When connecting pole negative value Welding is done with reverse polarity.

When welding, hands and face must be protected.

The metal that makes up the electrode rod melts under the influence of the arc along with its coating, as well as the surface of the workpiece being welded. From this moment, the electrode material represents drops in the slag, which enter the weld pool and mix with the metal being processed.

The size of the bath is directly dependent on the following criteria:

• the mode in which welding is carried out;
• design of the welded joint;
• cutting shape and dimensions of connecting edges.
• position in space;
• the speed of arc movement across the product.

The standard size of the bath is 6 mm deep, 8-15 mm wide and 10-30 mm long.

The distance between the two active areas (at the weld pool and the end of the electrode) is called the arc length. During the melting of the coating, a layer of gas is formed around the arc and bath, which displaces oxygen from working area, prevents it from interacting with the molten material.

The slag, which covers the drops of metal of the electrode, as well as the weld pool, prevents exposure to atmospheric air on the material being processed. The gradual removal of the arc ensures crystallization of the metal, which results in the formation of a connecting seam covered with a layer of hardened slag.

The advantages of this type of welding include the following:

• work can be performed with limited access;
• many types of electrodes allow welding different types steel;
• relatively quick change of materials to be joined;
• the process can take place in any position;
• The working equipment is light and transportable.

Disadvantages include low productivity compared to other types of welding, harmful conditions and the need for worker qualifications with high quality requirements.

It is not necessary to know everything about welding; for simple everyday situations, it is enough to follow the rules and basic requirements for work.

In a private house, in a country house, in a garage and even in an apartment - everywhere there are many jobs that require metal welding. This need is especially acute during the construction process. Here, especially often, something needs to be cooked or cut off. And if you can still cut it with a grinder, then there is nothing to reliably connect the metal parts with except welding. And if the construction is carried out with your own hands, then the welding work can be done independently. Especially in places where the beauty of the seam is not required. We will tell you how to properly weld by welding in this article.

Basics of electric welding

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

It's not really the right way welding)) At a minimum, you need

Types of electric welding

An electric arc can be formed by both direct and alternating current. AC current Welding transformers are welded, and inverters are used as permanent ones.

Working with a transformer is more complicated: the current is alternating, so the welding arc “jumps”, the device itself is heavy and bulky. The noise that both the arc and the transformer itself makes during operation is also quite annoying. There is one more problem: the transformer greatly “stresses” the network. Moreover, significant voltage surges are observed. The neighbors are not very happy about this circumstance, and neither is yours. household appliances may get hurt.

Inverters mainly operate from a 220 V network. At the same time, they are small in size and weight (about 3-8 kilograms), operate quietly, and have almost no effect on voltage. The neighbors won't even know you started using the welding machine unless they see you. Moreover, since the arc is caused DC, it doesn't jump, it's easier to mix and control. So if you decide to learn how to weld metal, start with a welding inverter.

Welding technology

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

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

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

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

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

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

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

How to weld metal correctly

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

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

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

How to choose a current for welding

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

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

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

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