How to make a weld. Inverter metal welding: tips for beginners

Welding is the most popular way to join metal products. But, often used, does not mean simple. The science of how to properly weld a seam must be learned in the same way as others. It is easy to acquire theoretical knowledge and even get a certificate of completion of specialized training. At the first experience, it turns out that it is not always possible to make a beautiful welding seam.

Experienced craftsmen know how to properly apply a weld. But, they may also face an emergency situation, as welding technology advances and industry produces more modern equipment. You should constantly improve your skills and learn new methods, how to properly weld a seam.

Types of welding

Different types of welding differ from each other in the way they influence the materials to be joined.

Arc. The most commonly used method due to its simplicity. In arc welding, an electrode is used as a melting tool. With it, an arc is excited and held throughout the welding process. The electrode is chosen depending on the brand of metal, and its diameter - on the width of the weld.
Gas. The heat source in gas welding is the torch. A flame comes out of it by the action of strong pressure, which was formed during the combustion of a mixture consisting of a combustible gas such as acetylene and oxygen.
semi-automatic. A mechanical device is used - a semi-automatic device. The role of the electrode is performed by the wire with its automated supply. Gas also enters there, the task of which is to protect the molten metal from the aggressive effects of the environment. It is possible to set various modes, which makes it possible to weld multi-pass welds semi-automatically.
Automatic. Unlike semi-automatic, the entire process is carried out by a welding machine. It is only necessary to configure the machine for a specific operation.
TIG welding. Popular with professionals. Attracts its versatility and the ability to weld metal of different thicknesses.

Regardless of what type of welding is used, the correct welding seam will be obtained as a result of compliance with the requirements of the technological process, preparatory work, and the implementation of recommendations.

Varieties of welds

How to make a welding seam depends largely on its type.

The geometrical parameters of the seam include its width, length, depth, bulge size. Beautiful welds can only be obtained with a successful selection of its parameters for each specific case.

Butt welds are obtained by the usual connection of metal surfaces or their ends. A lot of time for such a process is not required. Metal consumption is also minimal. When connected in a tee way, the result is a design that looks like an inverted "T".

The advantage of the method is that it can be used to connect elements that have a significant difference in width. The use of the "boat" setting makes the welding process more convenient and reduces the likelihood of defects. Usually such a connection is made in one pass.
The corner connection is usually made at a right angle, but slight deviations from this value are possible. A stronger connection is obtained by welding on both sides. The overlap method is suitable for thin parts. When applying one part to another, boiling is carried out from two sides.

An important point on how to properly lay the weld is the good choice of bevel edges. There are various options. In addition, it is possible to join without chamfering, for example, with an overlap method.

Training

A significant moment in its importance, how to make a beautiful seam when welding, is the correct preparatory work. Since the process is accompanied by the appearance of fire, it is necessary to carefully prepare the workplace of the welder performing the work. Provide him with protective clothing and a mask. Flammable objects and materials should not be located near the place of work.

The product to be welded must be cleaned of dirt, dust, residues of paint stains, grease and oil on its surface. In addition to mechanical action, the use of solvents or alcohol is permissible.

If welding equipment is used, then its performance should be checked first. Then select the mode and set the necessary parameters. If the device malfunctions, its operation is strictly prohibited.

Arc start

One of the main points on how to properly weld by welding is the competent excitation of the arc. You should choose one of the known methods. The first of these is that, holding the electrode in your hand, touch the metal with its tip and quickly pull it back to a distance of 2-4 millimeters. Delay threatens to stick the electrode to the metal. The result will be an arc. If this does not happen, you should try again.

Another way is to quickly move the electrode over the surface of the metal and immediately lift it a few millimeters. One of the secrets of how to properly apply a weld is to maintain a short arc throughout the welding process. This will ensure smooth welding and obtain a quality seam with a good appearance. However, if the arc is too short, the process may be interrupted, which will cause the appearance of a defect in the form of a crater. To continue work, the crater must be brewed.

A non-contact method of arc excitation is possible using an oscillator. It serves as an addition to the main welding machine. To excite the arc, the electrode should be brought closer to the metal surface at a distance of about 5 millimeters. Then you should press the corresponding button on the oscillator and wait for the appearance of the welding arc.

Electrode position

Knowing how to lay a weld begins with knowing how to choose the right electrode position. Otherwise, a situation may occur in which slagging of the seam occurs, which will not benefit its quality.
There are three options for the position of the electrode when welding. The first two assume its inclination in different directions within the same limits, and the third occurs at a right angle.

The "angle forward" method involves moving forward from the welder. It is suitable for welding thin metals in vertical and horizontal positions. With "angle back" the movement is carried out towards the welder. It is convenient to use at short distances for welding butt and fillet welds. In hard-to-reach places, use the 90 degree angle position. This is somewhat more complicated, but solves the issue with welding the ceiling seam.

Electrode movements

An ideal welding seam, or rather an approximation to it, is possible with a successful choice of the method of movement of the electrode during welding. The most common movements are along the axis of the electrode and along the axis of the seam. But simply moving in a given direction will not bring the desired result. This will result in a narrow thread-like seam. It can be used as the first seam in multi-pass welding.

To obtain the desired effect, the movements must be oscillatory. This will provide a seam of the desired width, good heating not only of the root of the seam, but also of its edges.

The trajectories along which the oscillatory transverse motion occurs:

zigzag;
the loop;
broken line;
herringbone or triangles;
crescent;
sickle.

All movements are performed across the direction of the weld.

A broken line is used when welding metal sheets is to be butt-welded in the lower position. The crescent is chosen for butt and fillet welds. Before welding with a herringbone, it is necessary to first make a surfacing of a small surface on which it will hold. A simple herringbone electrode technique is to move it horizontally and then place it slightly higher in the middle of the seam.

Crescent motions can be used in TIG welding. In this case, the width of the seam will be large, but it can be controlled during the welding process itself. The transverse movements of the crescent ensure good welding of the edges of the parts.

The use of a loop provides beautiful connections when welding thin metals. The chain of loops must be continuous. The use of loop-like movements is justified when it is necessary to warm up the edges of the seam well. This is especially important when welding high-alloy steel parts. The amplitude of reciprocating movements is selected depending on the required width of the seam.

The choice of a motion scheme for solving the problem of how to make a beautiful weld depends on its position in space. The seams are horizontal and vertical. The horizontal seam located at the top is called the ceiling. It is the most difficult to perform, since the welder must be in an uncomfortable position for a long time. A horizontal seam can be performed in two ways - movements to the left or right.

When welding in the vertical direction, the direction of movement of the seam is from the bottom up. The creation of a vertical seam is more difficult than a horizontal one, since there is an intense flow down of the molten metal. If you move from top to bottom, then the metal drops, when solidified, form a solid barrier to continue the seam. Welding a vertical seam should be carried out with a short arc.

Inclusions

Foreign inclusions are called cavities inside the seam, filled with slag, flux, oxide, foreign metal.

When slag particles enter the weld, a defect is formed, called slag inclusions. The welding seam is slagged when the edges and welding wire are not cleaned well enough to remove impurities and oxides. Other reasons why the weld is slagging include: welding with a long arc, a small current value, too high a speed of the welding process. If a multi-pass weld is carried out, then slags can get inside in the absence of stripping of the previous layers.

Slag sections reduce the cross-sectional area of the weld, which leads to a decrease in strength.
Flux inclusions occur as a result of the fact that the flux granules did not have time to dissolve in the liquid metal and did not float to its surface. To prevent this situation, it is necessary to use a high quality flux and prevent it from being accidentally introduced into the weld pool. Foreign bodies can enter the weld pool by accident.

Inverter selection

The correct weld will be obtained by choosing equipment suitable for specific welding conditions. The welding inverter is a reliable compact device that is easy to use. Characteristics allow you to generate current of different sizes, which makes it possible to weld parts of various thicknesses and different grades of metals. There is an automatic shutdown system in case of mains voltage fluctuations, overheating and too long operating time.

One of the important characteristics when choosing an inverter is its power. The operating instructions indicate the period of continuous operation of a particular model. Additional options make working with it more convenient.

Possible mistakes

Professional advice will help you learn how to get reliable and beautiful welds and how to weld them correctly. The main mistakes that do not allow you to get a quality seam include:

Too fast electrode movement. As a result, the seam is uneven.
Excessively slow lead speed. Burn-throughs are formed, which are a serious defect and are unacceptable in critical structures.
Incorrectly maintained angle of the electrode . It should be between 30 and 60 degrees. When these values are exceeded, the evenness of the seam is disturbed.
Welding of metals of different grades with very different characteristics, in particular, melting point. When one metal has already melted, and the second has only slightly heated up, then welding cannot occur. Cracks appear that need to be repaired.
Working with wet electrodes. Before welding, they must be dried or even ignited. Humidity causes uneven arcing.
Incorrectly selected welding mode, electrode type, current value.
Too large or small arc length.
Use of welding equipment with an overdue verification period.
Insufficient heating of the edges. To do this, it is necessary to select transverse oscillatory movements, the range of which corresponds to the width of the seam.
A large gap between parts can cause shrinkage.

Beautiful welds cannot be obtained if they have pores. There are many reasons for their appearance in the weld:

insufficient cleaning of the edges, leaving dirt, rust, scale on them;
high moisture content on the edges and electrode;
the presence of drafts in the welding zone;
low-quality electrodes;
a large difference in the chemical composition of the base and filler materials.

Over time, experience comes, how to conduct a welding seam correctly. This is the skill of a welder, whose profession is in demand and prestigious.

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 is required to be welded or cut off. And if you can still cut off with a grinder, then there is nothing to reliably connect metal parts except for welding. And if the construction is done by hand, then welding work can be done independently. Especially in those places where the beauty of the seam is not required. About how to cook by welding, we will tell in this article.

The basics of electric welding

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

This is not quite the right way to weld)) At a minimum, you need

Types of electric welding

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

Working with a transformer is more complicated: the current is alternating, therefore the welded arc “jumps”, the apparatus itself is heavy and bulky. Still a lot of annoying noise, which emits during operation and the arc and the transformer itself. There is one more nuisance: the transformer strongly “sets” the network. Moreover, significant voltage surges are observed. This circumstance is not very happy with the neighbors, and your household appliances may suffer.

Inverters mainly operate from a 220 V network. At the same time, they have small dimensions and weight (about 3-8 kilograms), they operate quietly, and have almost no effect on voltage. Neighbors won't know you've started using a welding machine unless they see you. In addition, since the arc is caused by direct current, it does not jump, it is easier to stir 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 the metal part and the other is the electrode.

The electrodes that are used for manual arc welding are 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 different 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 an electric arc to the melting zone: the weld pool.

How is a weld pool formed? Without understanding this process, you will not understand how to weld metal correctly (To increase the size of the picture, click on it with the right mouse button)

In the process, the protective coating also burns, partially melting, partially evaporating and releasing some hot gases. Gases surround the weld pool, protecting the metal from interaction with oxygen. Their composition depends on the type of protective coating. The molten slag also coats the metal, helping to maintain its temperature. In order to properly weld by welding, it is necessary to ensure that the slag covers the weld pool.

The weld is obtained 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 is formed on it - the result of the burning of protective gases. It also protects the metal from contact with the oxygen contained in the air. After cooling, it is beaten with a hammer. In this case, hot fragments scatter, therefore eye protection is required (wear special glasses).

How to weld metal

Learning how to properly hold the electrode and move the bath is not enough for a good result. It is necessary to know some subtleties of the behavior of the joined metals. And the peculiarity lies in the fact that the seam “pulls” the parts, which can cause them to warp. As a result, the shape of the product can be very different from what was intended.

Electric welding technology: before starting the seam, the parts are connected with tacks - short seams located at a distance of 80-250 mm from each other

Therefore, before work, the parts are fixed with clamps, ties and other devices. In addition, tacks are made - short transverse seams laid through several tens of centimeters. They fasten the parts, giving the product a shape. When welding joints, they are applied on both sides: in this way, the resulting stresses are compensated. Only after quiet preparatory measures begin welding.

How to choose a current for welding

It is impossible to learn how to cook by electric welding if you do not know which current to set. It depends on the thickness of the parts to be 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 supply 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 electrode movement - several times passing through one place. Another way is to put a thinner electrode. By combining all these methods, a good weld can be achieved even under such conditions.

Now you know how to cook by welding. It remains to develop the skills. Choose a welding machine, buy electrodes and a welding mask and start practicing.

To consolidate the information, watch the video tutorial on welding.

Welding is one of the main methods of fastening two elements, and welds are zones connecting two metal blanks to each other. Such solderings are obtained during the melting and subsequent cooling of the steel.

A good welder must know the types of welds and be able to apply all types of seams. . Without these skills, it is impossible to produce a high-quality and durable design.

Joint types

Welds are divided into 5 variations:

lap;
parallel;
butt;
corner;
t - figurative.

Lap laps are often used to create cylindrical tanks that are planned to be operated in a horizontal or vertical position. Welded elements overlap, but do not completely overlap. The result is a structure that looks like a step. Welded seams are applied from the end sides of the parts .

Parallel application methods are used to increase the strength of the structure. Both components are tightly applied to each other and fastened by welding from the side of the ribs. With this technique, it is possible to strengthen structures, the appearance of which will have a strong mechanical effect. However, this technology is forbidden to be used in the repair of moving mechanisms.

The butt version is the most popular. The parts to be welded must be in the same plane, one opposite the other. Such a joint is used to fasten water pipes, chimneys, storage facilities or steel columns. Also, this system is used in mechanical engineering, in the manufacture of air and water transport, in military plants. Yes, and the creation of such a "gluing" requires a minimum of money and time.

Fillet welds are well suited for joining multiple workpieces that need to be placed at right angles. The workpiece is made as follows: parts are installed at an angle of 90 ° (in the form of the symbol “G”), and a weld is applied at the junction of the edges . This welding is common both in industry and in the private sector. And with its help you can make strong supports or boilers.

A T-weld or tee weld is unlike any other, as the finished part will look like the letter "T". It will be difficult for an inexperienced person to create this, since it is important to take into account the restrictions related to holding the electrode in the process (it is recommended to adhere to an angle of 60 °). In this case, the thickness of the sheets to be joined may vary. Also, more wire will be required to complete, and elements welded by the T-weld method may come out with defects.

Work technique

The movement of the rod in a solid line will not be enough for a good weld. , and to become a master of your craft, you need to understand the technique of using the apparatus. The main features of the technology are constant control of the gap between the components. If the distance is too small, then the steel will not warm up well, which will negatively affect its strength. Both the speed of the tripod and the basic soldering procedure should be controlled. The main thing is that the molten metal is evenly distributed over the groove.

How to suture correctly :

Cook in circular or zigzag motions. The trajectory must be maintained throughout the soldering.
Hold the handle at the correct angle. The sharper the slope, the shallower the steaming depth.
Control the rate of movement of the electrode. It all depends on the voltage of the device. High current allows you to move the holder at a faster speed, and the seams will be finer in the end.
Properly choose the layers of soldering. Several rows can be made in the butt places, however, a tee weld is more often made by this technique.

Taking into account these rules will help to achieve the desired result, and the specialist will accurately produce any type of welding seam.

Application methods

Application methods include:

Horizontal type. According to the rules, you can apply a seam both from right to left, and in the opposite direction. It is important to observe an acceptable angle of inclination here, since excess molten metal will flow out. If a person has few skills, then the entire procedure can be completed in 2-3 passes.
Vertical type. The working surface can be located in the ceiling or wall areas. Welding joints can also be made in two ways: from top to bottom, and from bottom to top. However, it is better to choose the first option, since the heat from the arc contributes to a high heating of the alloy.
Ceiling type. The whole process must be carried out very quickly, while maintaining a stable pace of the rod. Also, to keep the alloy in the seam, you will need to make rotational movements. It should be noted that the current variety is the most complex, and work should be started after gaining the necessary experience.

From the first time it is difficult to understand what varieties there are and to study all the technologies. But regular practice will make any beginner a true professional.

Quite often, it is required to connect metal parts or fragments of parts. There are several ways to get the desired result. Most often, the method of electric welding is used to connect iron and steel parts.

What is it based on?

How to cook with electric welding? In order to understand the principle, you need to remember the physics from the school curriculum. One of them is connected to the working part. When the electrode comes into contact with this surface, a depression forms at the point of contact, which is filled with molten metal as the electrode moves. The edges of the metal parts melt under the influence of enormous temperature and turn into a single whole.

Arc ignition methods

When learning how to weld metal with electric welding, it is worth learning a few things about the method itself. The distance and electrical high-temperature pulse between the workpiece and the electrode is called an arc. There are two ways to create such conditions:

In the first case, the electrode (quickly touching) is “strike” over the iron, as if with a match. The resulting arc must be maintained by conducting an additive a few mm from the working surface of the metal.
In the second case, the tip of the electrode must be sharply tapped on the workpiece.

The resulting arc should not go out. If this does happen, before the electric welding continues, the seams must be cleaned of scale. Neglect of this rule leads to the formation of a hole.

Importance of amperage for welding

The calculation of the current strength corresponding to the thickness of the electrode will show in practice how to learn how to cook with electric welding. With insufficient current, the electrode will stick, and the arc will go out. With a large current, the metal will splatter and burn. If you use a welding transformer, then an electrode of 1 mm corresponds to a current of 30-35 A. When using an electrode of 3 mm, a current of 80 A corresponds. If you increase the current, iron can be cut.

The electrodes are selected taking into account the chemical composition of the metal. There are several types of this filler material:

steel;
bimetallic;
cast iron;
copper;
brass.

All of them are marked with an index and numbers indicating what metal of what hardness and thickness each type is intended for.

When learning how to properly weld by electric welding, you need to remember that in order to obtain high-quality seams, the electrodes must match the thickness of the metal.

Welding of flat sheets of metal

Thin metal (from 1 to 3 mm) is joined end-to-end without gaps and additives, achieving a good match of aligned edges.

For a better fit of the joints of thicker sheets (from 3 to 8 mm), the edges should be cut at right angles. Between the sheets leave a gap of up to 2 mm. Material 8 mm thick is connected by double-sided welding. To connect thicker planes, the edges are cut with a bevel.

How to start learning to cook iron

Learning how to cook with electric welding starts with the simplest processes.

The prepared parts are fixed on a horizontal surface (on a welding table).
Tacks fasten them around the edges and in the center.
It is necessary to insert a new additive into the holder and attach a ground clamp to the part.
First, work out the correct tilt of the electrode (about 75 degrees) in the direction of the arc. In this case, it is necessary to make movements that, as it were, rake the molten metal into the junction.
The end of the electrode should be in the center of the seam. Due to the observance of the angle of inclination, the drops flow more evenly from the hot electrode and form an even, high-quality roller.
After cooling the workpiece, it is necessary to beat off the slag from the surface of the part.

Time after time, as you gain experience, the seams will turn out smoother and more accurate.

How to make a vertical seam

How to cook a vertical seam with electric welding? The main thing is to start by following all the recommendations. Welding vertical seams is similar to working horizontally, only a little more complicated. Blanks are picked up in two or three places. Then welding is carried out only from the bottom up, sticking drop by drop. Gradually, the entire gap is filled with hot metal. How to learn to cook with electric welding? The task is to merge both edges, melting them with a welding arc, at the same time directing metal drops there from the end of the electrode heated to a state of liquid.

You can weld the seam not with drops, but with the so-called "eight", but only an experienced specialist can handle this. So, if you are interested in knowing how to learn how to weld a vertical seam by electric welding, it is first recommended to look at the work of an experienced welder, listen to the advice of the masters. And only then independently start the process.

How to make a beautiful and strong corner seam

Correctly making the so-called "tee" seam is not as easy as learning how to cook with electric welding. This seam is used if you want to fasten parts at different angles. The metal parts are installed so that the welding flows into the very corner. The welded parts fixed by the “boat” are tacked from opposite sides. In addition, one edge of the workpiece rises slightly higher. The welding process must begin from the bottom edge. In this case, carefully following the instructions on how to properly weld by electric welding, the quality of the weld can be significantly improved.

Which one is better to use

The old ones with an adjustable magnetic gap that allows you to adjust the current strength are transformer ones. There are many variants and models that have rheostats and additional chokes on the primary or secondary sides of the transformers.
Inverter machines are more modern welding devices. Working from an increased frequency, the transformer of such units has smaller dimensions and low weight. In such devices, you can smoothly adjust the welding modes. The settings of the latter must be carried out carefully, otherwise the device can quickly fail.

Pipe welding methods

In the absence of experience, it is better to learn how to weld a pipe by electric welding on thick metal. Several passes are made depending on the wall thickness of the pipe. Multi-layer welding improves the mechanical properties of the resulting seam, the connection becomes stronger.

First, a half ring is welded in one direction, then in the second. With the method of conducting the seam "from top to bottom", 4-mm electrodes with organic sputtering are used. With a short arc, relying on the resulting "visor", the attachments are driven by small transverse vibrations.

When working according to the “bottom up” method, the speed is sharply reduced. Conducting transverse oscillations of the electrode is done in 3-5 mm.

When from pipes, you first need to prepare and lay out all the material on the welding table or stand. Then they are centered and tightened to obtain the gap required for welding. The assembled joints are tacked together.

Pipes with a small diameter are connected by continuous welding, with a large diameter - by an intermittent method. After completion of all welding processes, the working surface of the metal is cleaned of scale, frozen spatter, and slag. A control inspection is carried out to detect cracks or burns, outgoing craters or pores. In the presence of poorly welded places, the seam is restored.

For your own safety, you need to work while welding in suede gloves and mittens, in a welder's mask, in tarpaulin or thick leather boots and in a cotton robe. Be sure to have a fire extinguisher or a container of water nearby.

In electric welding, an electric arc is used to heat the metal. It occurs between the part and the electrode - a rod made of conductive metal (sometimes non-metal). The temperature of the arc melts the metal. The fusion zone at the junction of parts is called a weld (weld) seam. For different metals and different types of compounds, the welding technique, the position of the electrode, the speed of its movement, and the amplitude can change. How to properly weld a seam so that the connection is not only reliable, but also beautiful, let's talk further.

Types of welds and joints

Seams have a fairly extensive classification. First of all, they are divided according to the type of connection of doers. Depending on the requirements for reliability, the seam can be applied on one or both sides. With double-sided welding, the structure is more reliable and holds its shape better. If there is only one seam, it often turns out that the product is warped: the seam “pulls”. If there are two of them, these forces are compensated.

Welds, depending on the type of connection, are butt (butt), tee, overlap and corner (To increase the size of the picture, click on it with the right mouse button)

It is impassable to note that in order to obtain a high-quality weld, the metal should not be rusty. Therefore, the welding spots are pre-sanded or treated with a file - until the rust disappears completely. Further, depending on the requirements, grind or not the edge.

Butt joint (butt seam)

A butt seam in welding is used when joining sheet metal or pipe ends. The parts are laid so that there is a gap of 1-2 mm between them, if possible, they are rigidly fixed with clamps. During the welding process, the gap is filled with molten metal.

Thin sheet metal - up to 4 mm thick - is welded without prior preparation (rust cleaning does not count, it is required). In this case, cook only on one side. With a thickness of parts from 4 mm, the seamit can be single or double, but edge sealing is required in one of the ways shown in the photo.

With a part thickness from 4 mm to 12 mm, the seam can be single. Then the edges are cleaned in any of the ways. It is more convenient to do one-sided preparation with a thickness of up to 10 mm, and thicker parts are cleaned more often in the form of the letter V. U-shaped cleaning is more difficult to perform, therefore it is used less often. If the requirements for welding quality are increased, with a thickness of more than 6 mm, stripping on both sides and a double seam on one and the other side are necessary.
When welding metal with a thickness of 12 mm or more butt, a double seam is definitely needed, it is impossible to heat such a layer on one side. Edge trimming is double-sided, in the form of the letter X. It is unprofitable to use V or U shaped edge trimming with such a thickness: several times more metal is required to fill them. Because of this, the consumption of electrodes increases and the welding speed is significantly reduced.

Cutting metal edges when joining parts end-to-end (To increase the size of the picture, click on it with the right mouse button)

If, nevertheless, it is decided to weld metal of great thickness with one-sided cutting, it will be necessary to fill the seam in several passes. Such seams are called multilayer. How to weld a seam in this case is shown in the figure below (numbers indicate the order of laying metal layers during welding).

How to weld a butt weld: single-layer and multi-layer (To increase the size of the picture, click on it with the right mouse button)

Lap joint

This type of connection is used when welding sheet metal up to 8 mm thick. It is boiled on both sides so that moisture does not get between the sheets and there is no corrosion.

When performing a seam with an overlap, it is necessary to correctly select the angle of the electrode. It should be around 15-45°. Then a reliable connection is obtained. With a deviation in one direction or another, the bulk of the molten metal is not at the junction, but to the side, the strength of the connection is significantly reduced or the parts remain not connected at all.

How to hold the electrode correctly when welding with an overlap (To increase the size of the picture, click on it with the right mouse button)

Tee and corner connection

The tee joint in welding is the letter "T", the angular - the letter "G". A tee joint can be with one seam or two. Edges can also be cut or not. The need for edge cutting depends on the thickness of the parts to be welded and the number of seams:

metal thickness up to 4 mm, single seam - without edge processing;
thickness from 4 mm to 8 mm - without edging double seam;
from 4 mm to 12 mm - single seam with cutting on one side;
from 12 mm, the edge is cut off on both sides, and two seams are also made.

The fillet weld can be considered as part of the tee. The recommendations here are exactly the same: thin metal can be welded without cutting edges, for greater thickness, you have to remove the part from one or two sides.

Corner and tee joints sometimes have to be welded on both sides (two seams). To properly weld such a seam, the parts are rotated so that the metal planes are at the same angle. In the photo, this method is signed "in the boat." This makes it easier to calculate the movement of the electrode, especially for a beginner with welding.

How to weld a seam: “into a boat” and when joining metals of different thicknesses

When connecting thin and thick metal, the angle of inclination of the electrode should be different - about 60 ° to the thicker part. In this position, most of the heating will fall on it, thin metal does not burn through, which can happen if the angle of inclination is 45 °.

Fillet Welding

When welding fillet welds, the position and movement of the electrode must be monitored. You should get a seam with uniform filling. It is easier to implement this if you put the parts for welding “into the boat”, but this does not always work out.

If the lower plane is horizontal, it often turns out that there is little metal on the vertical plane, as well as in the very corner: it stacks down. This happens if the electrode is at the top of the corner for less time than near its side surfaces. The movement of the electrode tip must be uniform. The second reason is that the electrode diameter is too large, which does not allow you to go lower and warm up the junction normally.

To avoid the appearance of this defect, the arc is ignited on a horizontal surface (at point "A"), moving the electrode to the vertical surface, then return it to its place in a circular motion. When the electrode is above the joint, it has a slope of 45 °, as it moves up, the angle slightly decreases (the figure in the picture on the left), when moving to a horizontal surface, the angle increases. With this technique, the seam will be filled evenly.

Fillet Welding - Electrode Position and Movement

When welding corner joints, also make sure that the time spent by the electrode at all three points (on the sides and in the center) is the same.

Position in space

In addition to different types of joints, seams can be located in space in different ways. They are in the down position. For the welder, this is the most comfortable. This is the easiest way to control the weld pool. All other positions - horizontal, vertical and ceiling seam - require certain knowledge of welding techniques (read below how to weld such seams).

How to weld a seam

When welding in the lower position, no difficulties arise even for a novice welder. But all other provisions require knowledge of technology. Each position has its own recommendations. The technique for making welds of each type is discussed below.

Welding vertical seams

During welding of parts in a vertical position, the molten metal slides down under the action of gravity. To prevent droplets from coming off, a shorter arc is used (the tip of the electrode is closer to the weld pool). Some craftsmen, if the electrodes allow (do not stick), generally lean them on the part.

Metal preparation (grooving) is carried out in accordance with the type of joint and the thickness of the parts to be welded. Then they are fixed in a predetermined position, connected with a step of several centimeters with short transverse seams - “tacks”. These seams do not allow the parts to move.

A vertical seam can be welded from top to bottom or from bottom to top. It is more convenient to work from the bottom up: this is how the arc pushes the weld pool up, preventing it from lowering down. This makes it easier to make a quality seam.

This video shows how to properly weld a vertical seam by electric welding with the movement of the electrode from bottom to top without separation. The short roll technique is also demonstrated. In this case, the electrode movements occur only up and down, without horizontal displacement, the seam is almost flat.

It is possible to connect parts in a vertical position with an arc separation. For novice welders, this may be more convenient: during the time of separation, the metal has time to cool. With this method, you can even rest the electrode on the shelf of the welded crater. It's easier. The pattern of movements is almost the same as without a break: from side to side, loops or a “short roller” - up and down.

How to cook a vertical seam with a gap, see the next video. The same video tutorial shows the effect of current strength on the shape of the seam. In general, the current should be 5-10 A less than recommended for a given type of electrode and metal thickness. But, as shown in the video, this is not always true and is determined experimentally.

Sometimes a vertical seam is welded from top to bottom. In this case, when starting the arc, hold the electrode perpendicular to the surfaces to be welded. After ignition in this position, heat the metal, then lower the electrode and cook in this position. Welding a vertical seam from top to bottom is not very convenient, it requires good control of the weld pool, but in this way you can achieve good results.

How to weld a vertical seam by electric welding from top to bottom: the position of the electrode and the movement of its tip

How to weld a horizontal seam

A horizontal seam on a vertical plane can be carried out both from right to left and from left to right. There is no difference, to whom it is more convenient, he cooks like that. As when welding a vertical seam, the bath will tend to go down. Therefore, the angle of inclination of the electrode is quite large. It is selected depending on the speed of movement and current parameters. The main thing is that the bath stays in place.

If the metal flows down, increase the speed of movement, warming up the metal less. Another way is to make arc breaks. During these short intervals, the metal cools down a little and does not drain. You can also reduce the current a little. Only all these measures are applied in stages, and not all at once.

The video below shows how to properly weld metal in a horizontal position. The second part of the video about vertical seams.

Ceiling seam

This type of welded joint is the most difficult. Requires high skill and good control of the weld pool. To perform this seam, the electrode is held at right angles to the ceiling. The arc is short, the speed of movement is constant. Perform mainly circular movements that expand the seam.

Weld cleaning

After welding, scale splashes, drops of metal and slag remain on the metal surface. The suture itself is usually convex, protrudes above the surface. All these shortcomings can be eliminated: clean up.

Cleaning the seams after welding is done in stages. At the first stage, with the help of a chisel and a hammer, scale and slag are knocked off the surface. On the second, if necessary, compare the seam. Here you need a tool: a grinder equipped with a grinding disc for metal. Depending on how smooth the surface should be, different abrasive grits are used.

Sometimes, when welding ductile metals, tinning is required - coating the weld with a thin layer of molten tin.

Weld defects

Beginning welders often make mistakes when making seams that lead to defects. Some of them are critical, some are not. In any case, it is important to be able to identify the error in order to correct it later. The most common defects among beginners are the unequal width of the seam and its uneven filling. This happens due to uneven movements of the electrode tip, changes in the speed and amplitude of movements. With the accumulation of experience, these shortcomings become less and less noticeable, after a while they disappear altogether.

Other errors - when choosing the current strength and the size of the arc - can be determined by the shape of the seam. It is difficult to describe them in words, it is easier to depict them. The photo below shows the main shape defects - undercuts and uneven filling, the reasons that caused them are spelled out.

Lack of fusion

This defect consists in incomplete filling of the joint of parts. This disadvantage must be corrected, as it affects the strength of the connection. Main reasons:

insufficient welding current;
high speed of movement;
insufficient edge preparation (when welding thick metals).

It is eliminated by correcting the current and reducing the length of the arc. Having chosen correctly all the parameters, they get rid of such a phenomenon.

undercut

This defect is a groove along the seam in the metal. Usually occurs when the arc is too long. The seam becomes wide, the temperature of the arc for heating is not enough. The metal around the edges quickly solidifies, forming these grooves. "Treated" by a shorter arc or by adjusting the current strength upwards.

With a corner or tee connection, the undercut is formed due to the fact that the electrode is more directed to the vertical plane. Then the metal flows down, a groove forms again, but for a different reason: too much heating of the vertical part of the seam. Eliminated by reducing the current and / or shortening the arc.

burn

This is a through hole in the weld. Main reasons:

too high welding current;
insufficient speed of movement;
too much gap between the edges.

The correction methods are clear - we are trying to choose the optimal welding mode and the speed of the electrode.

Pores and bulges

The pores look like small holes that can be grouped in a chain or scattered over the entire surface of the seam. They are an unacceptable defect, as they significantly reduce the strength of the connection.

Pores appear:

in case of insufficient protection of the weld pool, an excessive amount of protective gases (poor quality electrodes);
draft in the welding zone, which deflects protective gases and oxygen enters the molten metal;
in the presence of dirt and rust on the metal;
inadequate edge preparation.

The sags appear when welding with filler wires with incorrectly selected welding modes and parameters. Represent a numb metal that has not connected to the main part.

Cold and hot cracks

Hot cracks appear as the metal cools. Can be directed along or across the seam. Cold ones appear already on a cold seam in cases where the loads for this type of seam are too high. Cold cracks lead to the destruction of the welded joint. These shortcomings are treated only by repeated welding. If there are too many flaws, the seam is cut off and re-applied.

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