You can become a welder after 2 years of study at a vocational school or college; in extreme cases, you can take courses. For those who do not want to do this professionally, but simply want to skillfully perform welding seams, the following selection of common welding seams will help.
If electric arc welding is used, then the electrodes at constant current move in one direction, which is determined in accordance with the polarity.
Welding inverters of the new generation are superior in accuracy to transformers, generators and rectifiers previously used for welding; the polarity on them can be set independently. Beginners are recommended to master welding using inverters.
The welding machine is supplied with current through wires with quick-release terminals. The conductors must be made of copper and insulated; they conduct current, and the synthetic film functions as a separator.
Electrodes for metal welding are made of welding wire. But for cast iron, filler wire with a graphite rod is used. Cast iron, unlike steel, is a very brittle material, and its welding must be carried out using a cold method. When welding, you must constantly monitor the heating of its surface, otherwise cracks may occur. The seam is not made in one piece, but in snatches with obligatory forging.
On the lap weld it can be seen that when making wide movements with the electrode, undercuts are formed due to the thin platinum. At the beginning of the seams there are pores that arose as a result of poor stripping of the metal.
The main condition for obtaining beautiful rotation seams is the use of a suitable welding method and arc placement.
Today the following types of electric arc welding are known:
At home, these types of welding are practically not used. Therefore, let’s move on to consider the fourth type of welding work - manual electric arc welding.
Manual arc welding is based on the use of a special electrode in a coating
Electric welding machines for manual welding are divided into two types - alternating current and direct current. The use of alternating current allows the design of devices with high performance and power. The advantage of direct current, due to the lack of polarity reversal, is a smoother weld with less metal spatter.
In 1802 V.V. Petrov discovered the phenomenon of galvanic voltaic arc.
A device for welding metals using “electrohephaestus” was patented in 1882 by N.N. Benardos.
Russian engineer N.G. Slavyanov first used an electrode for welding in 1888.
In 1932, Soviet physicist K.K. Khrenov. Successful welding of metals under water was carried out.
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The operation of the welding machine is based on the creation of an electric arc at the point of contact of two metal parts. High temperature (up to 7000 o C) melts the material to a liquid state and diffusion occurs - mixing at the molecular level.
The fundamental difference between welding and gluing is the absence of auxiliary materials - the parts being joined are transformed into a monolithic structure.
Therefore, it is necessary to clearly understand that for the correct application of welding, only homogeneous metals can be used. You cannot weld aluminum to iron or copper to stainless steel. The melting point of different materials is different, and the creation of alloys is not within the capabilities of welding equipment.
There are various welding machines for welding iron structures.
The main advantage of inverter welding is the improvement of the dynamics of the electric arc, as well as a noticeable reduction in the weight and dimensions of the installation (compared to direct transformers). In addition, it became possible to smoothly regulate the output current, which significantly increased the efficiency of the unit and ensured ease of ignition of the arc during operation.
But there are also disadvantages:
Before you start welding, you need a welding machine and equipment:
The place where welding work is carried out is cleared of flammable materials and equipped with fire extinguishing means - water, sand, technical soda. If this is an enclosed space, it is necessary to arrange supply and exhaust ventilation.
Necessary fire-fighting equipment at any site
To successfully master the technique of permanently joining metal parts, you need to master 4 basic skills, without which not a single “welding session” is complete.
The basis for setting up a welding machine is the correct selection of current and voltage output to the terminals. Despite the simplicity of the formulation, the topic of customization deserves a separate discussion. But if we briefly formulate the setting criteria, we can distinguish 5 main parameters:
In order to accurately select the current value, the easiest way is to use ready-made tables.
But due to the fact that each device has its own design features and technological nuances, the final word still remains with the “scientific poking method” - the empirical selection of the required current experimentally.
Setting the welding current depending on the electrode diameter
Current selection mode for welding standard butt joints:
A one-sided seam connects the surface of parts on one side, a double-sided seam connects the surface of parts on two opposite sides.
Examples of welding parts using various seams
You can also use a universal table for a wide range:
A simple rule is easy for a novice welder to remember. If the current exceeds the required value, the electrode will burn through the workpiece. If the current is lower than necessary, the part is not welded, the deposited metal falls off when exposed to mechanical means.
The electrode can be connected to the positive or negative current output. If “+” is connected to the part, then the polarity is called straight. If “-” - reverse. Accordingly, with direct polarity there is a “minus” on the electrode, and with reverse polarity there is a “plus”. The difference between these positions is that more heat is always generated at the “positive” terminal. Experienced welders use this phenomenon to solve specific problems. For example, by manipulating the polarity, you can cook thin-sheet stainless steel that is sensitive to overheating. To do this, “plus” is applied to the electrode, and “minus” is applied to a sheet of thin metal.
One of the electrode connection options
The welding process begins with the ignition of an electric arc. In all types of manual welding, the arc is created by briefly touching the electrode to the part. In this case, a sharp heating of the end of the electrode occurs to a temperature sufficient to establish an arc discharge.
The process of igniting an electrode arc requires certain skills
After a short circuit, if the arc ignites, it is necessary to maintain a distance between the end of the electrode and the part of 3–5 mm. In this case, it is necessary to take into account the fact that the length of the electrode decreases as welding progresses. When exceeding a distance of 5 mm. the arc is interrupted when the decrease is less than 3 mm. the electrode may stick to the workpiece or cause large splashes of molten metal.
To create a good seam, various arc patterns have been developed along the welded area. In this case, it is considered important not only to melt the edges of the parts being welded, but also to fill the weld pool with the required amount of metal deposited from the electrode.
Various options for the trajectory of the electrode end
This can be achieved by maintaining a constant length of the electric arc and systematically moving the end of the electrode along a certain trajectory.
When producing a seam without transverse movements, the width of the joint is usually equal to b = (0.8–1.5)xd el. Where b is the width of the welded joint, and d is the diameter of the weld
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Today there are many different ways of joining metal products. They can be divided into two groups:
Classification of welding seams.
The connections of the first group include parts that can be separated without disturbing the connecting elements, for example, a bolt with a nut. It is the second connection that is the most reliable. In this case, the parts cannot be separated without breaking the connecting part. We are talking about welding and riveting joints. When it is necessary to obtain a high-quality and reliable connection, a welding seam is considered the best. Many people buy welding machines to weld parts, but have absolutely no experience. After several unsuccessful attempts, they have a question: how to properly lay a welding seam? To do this you need to know a few basic rules.
The welding process is the joining of metal using electric arc welding. The connected parts are melted using an electric arc, as well as an electrode consisting of a metal rod with a special coating. The quality and reliability of the weld is influenced by many different factors:
Covered metal electrode welding diagram.
Types of welding that are used in everyday life and industry are divided into several groups:
When gas press welding is used, an open flame of acetyl oxygen is used. The positive side of this method is considered to be high productivity. This method has become widespread in the gas and oil industries. It often occurs when pipelines are laid. This method is also widely used in mechanical engineering.
Resistance welding occurs at low voltage but high electric current. This method can be used for spot and butt welding.
Semi-automatic welding circuit diagram.
To master the technological process of welding work, you first need to have the appropriate welding equipment. You can rent it or buy it. Today, stores offer a wide range of welding machines that have a device that makes it possible to adjust the current strength. A home craftsman can make a welding machine himself, but he cannot do without an electrical energy converter. These devices come in several varieties.
Transformer. Designed to produce direct current when you have to use a household outlet. When purchasing such a unit, you must always remember that inexpensive models are not able to maintain stable operation of the electric arc. Voltage leakage occurs very often. The negative side is also their mass; they are heavy and clumsy.
Rectifier. This is a device that converts household current into direct current. The device differs from a transformer in the stable operation of the electric arc. The quality of the weld is quite high.
Inverter. The latest converter that allows you to work on any type of current. Always produces high quality welding. The seams are even and smooth. The device is very compact, light weight, and easy to light. The inverter is characterized by high performance and speed.
For normal operation of electric welding, there must be a stable arc. This consistency depends on the correct choice of the gap between the part being welded and the electrode coating. The arc burns best when the gap is 5 mm.
Technique for making welds.
The high temperature of the arc causes the part and the metal rod of the electrode to melt. At this time, all the depressions that were formed as a result of melting are filled. When the electrode moves slowly along the surface of the seam, voids are filled.
In order to be proud of the resulting seam, you need to choose the right electrode. To do this, you need to know the metal composition of the part that will need to be welded. The selection of an electrode is based precisely on these parameters. Electrodes are manufactured in several types. They can be:
By marking the electrode, you can determine the viscosity of the resulting weld; the numbers will tell you about the hardness of the metal. The main rule when choosing an electrode is its size. It must match the thickness of the metal.
For high-quality electric welding, so that the seam looks neat and durable, it is necessary to select the correct inclination of the electrode. Typically this angle is 75 degrees relative to the direction of the electric arc. In order for an arc to appear, you need to strike the surface of the metal and, when a flash appears, quickly lift the electrode. When the arc appears, it must be slowly drawn along the seam. An arc will also occur when the electrode is tapped on the surface.
To obtain a stable arc, the current must be adjusted correctly. If it is insufficient, the arc will go out very quickly, and the electrode will “stick”. When the current strength is high, the metal splashes in all directions and it begins to burn.
During operation, the electrode melts and gradually decreases in size. In this regard, you need to constantly move it towards the part, maintaining the required distance for a stable arc. If this is not done, the arc will quickly go out.
During the welding process, a weld pool is formed, which is a liquid mixture of molten metal and a melting coated metal core. When there is a constant smooth movement of the electrode with a maintained gap, the quality of the seam will be the most reliable, and the mechanical performance will be at its best. The seams will look aesthetically pleasing.
After welding, slag is formed over the entire surface of the seam.
It is removed with small blows of a hammer. Then the seam is cleaned with a wire brush. To learn how to weld metal well, you need constant training and a desire to get excellent quality work. Before you start working on your own, it’s worth watching how experienced welders work.
Of course, welding is a very complex and difficult job. It is almost impossible to instantly master all the nuances of this matter. It will take a lot of time to master all the tricks of welding. Once you have experience and skills, you will be able to produce original and beautiful products using welding.
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Ceiling welding is considered one of the most difficult types of welding because the weld pool is located upside down. Welding ceiling seams requires a precise sequence of all actions. If you do not follow the rules and recommendations, you can get a poor-quality connection, which can lead to leaks of hot metal.
When making a ceiling seam, you need to follow safety precautions and protect your face and hands from possible contact with hot drops of metal.
Note! Preparatory work before welding ceiling seams is accompanied by a number of difficulties. This is due to the fact that during the welding process, molten metal can flow down and accidentally fall on the skin of the person performing the weld. That is why experienced specialists, knowing how to weld such a seam, use special welding techniques that ensure strict compliance with safety rules.
Before connecting ceiling seams, you must clearly understand all the requirements and not neglect to fulfill the mandatory conditions. This information is especially important for novice welders.
If your workpieces are more than one centimeter thick and you do not know how to weld a ceiling seam, then know that in such a situation welding must be done in stages. At the very beginning of work, you need to use an electrode whose diameter does not exceed 3 mm; at all other stages, an electrode with a diameter of 4 mm is used.
Note! Welding a ceiling seam involves creating not only horizontal seams, but also connections along a certain slope (from 10 to 80°C). In this case, both manual welding and semi-automatic welding can be used. You can also use arc welding using coated electrodes.
As already noted, the main distinctive feature of such welding is based on an inverted weld pool and holding the hot metal by tension force. It is very important to maintain the minimum size of the bath and sometimes move the electrode to the side so that the metal has time to cool and set. In addition, this welding method will protect your connection from cracks.
The first method is considered the simplest and is well suited for inexperienced welders. Options involving ladder and back-and-forth welding are more complex and time-consuming. But such a connection will be of better quality.
Initially, the places that will be welded must be well treated by cleaning the edges with a grinder or a metal brush. Then the root of the seam is welded with an electrode (3 mm). Through it, a roller of molten metal is formed. If it is necessary for the roller to be on the reverse side, then the electrode is directed into the gap in small short throws. Monitor and control the uniform arc burning. The resulting roller must be freed from slag. If its shape is too convex, then it is necessary to bring it to pure metal. As already mentioned, in the following stages an electrode with a large diameter (4 mm) is used.
In order to obtain a reliable and durable seam, all safety regulations must be followed. Not only the quality of the seam, but also your personal safety depends on compliance with the rules.
In conclusion, it is worth noting once again that welding ceiling seams is a rather labor-intensive and energy-consuming process. It is quite difficult for a novice welder to make this type of connection. In order to do the job efficiently and create a good, strong seam, you need to gain special knowledge, master the technique of working with a welding machine and become familiar with all the nuances of this type of work. It’s better to practice welding some parts first. If you do not have enough knowledge and experience, then it is better to entrust this process to specially trained people. In any case, both experienced welders and beginners must strictly follow safety rules. Accurate compliance with all requirements and instructions is the key to your personal safety.
One of the most inconvenient and difficult positions for welding is the ceiling. But it is worth mastering this type of connection due to the automatic increase, which has learned to apply high-quality sutures in such a spatial position. This is in demand at enterprises whose activities are related to laying, and at construction sites. This skill is also useful in everyday life, when welding heating or gazebos. Some elements of a metal garage cannot be assembled without welding joints at the top. How to weld a ceiling seam using electric welding? What are the main precautions and optimal device settings?
Many welders do not like ceiling seams because of the difficulties in their execution. A beginner’s results can often be poor, which discourages them from learning. But if you understand the main problems and prevent them as much as possible, then pretty soon, after training, you can master this difficult connection.
Welding a ceiling seam with an inverter or transformer is significantly different from working on a similar product in the lower position. When metal is welded on the floor, the weld pool spreads over the joint, and the welder only needs to ensure that the joint is properly filled, preventing slag from getting in front of the pool. When the ceiling serves as the working surface, the molten metal tends downward under its own weight.
The slag, being in a liquid state, also constantly drips, which interferes with the welding. These splashes hitting the ground scatter even more, hitting the welder and surrounding objects. The main difficulty when arc welding in the ceiling position of the seam is connecting the sides of the product. A weld pool forms on one edge, but there is no way to bond both sides with metal.
Welding of ceiling seams is performed at a reduced current, which leads to frequent sticking of the electrode and lack of penetration. One more. The body position with the head thrown back and the arm raised up quickly tires the welder. Therefore, frequent breaks are simply necessary for quality work. Understanding these complexities will help you tune in to the challenges and take steps to make the process easier to implement.
To understand how to properly perform this type of connection, you need to know the basic rules used by experienced welders. Additionally, you can see how to weld a ceiling seam using electric welding in the video. Here are the main points:
Ceiling seams can be made using an inverter or a conventional transformer. It is important to correctly set the current strength, which is 25% lower than when welding on the floor. For example, for plates 5 mm thick, 100A is sufficient. It will be easier to work if the cable is not heavy. This will make it easier to control the end of the electrode and your hand will get less tired. You can also loop the cable around your hand to reduce the strain on your wrist.
Electrodes for ceiling welding are suitable with a diameter of 3 and 4 mm. It is important to use them to reduce the amount of splashing. If beginners use short electrodes, this will allow them to manipulate the arc more confidently.
For ceiling seams, you should wear a thick jacket and trousers. Gloves must cover the cuffs, otherwise scale will reach the elbows and burn the skin. A hat or cap without a visor is required on the head. It is important to choose trousers of such length that they cover the collar of the shoe to prevent molten particles from getting inside.
Since the spray hits the ground and spreads further, there should be no flammable objects nearby. You need to use safety glasses to beat off the slag, because it will fall down on the welder. Frequent rest will allow you to relieve stress from the muscles of your neck and arms and get the job done efficiently.
Welding in the ceiling position is not mastered immediately. It takes practice and patience. It’s good to take a few minutes a day and weld two pieces of pipe or corner to the table and try to weld them from below. Having mastered this method, you can safely weld pipes and metal structures of any complexity.
› How to weld using electric welding: weld metal pipes and make beautiful seams.
A weld is one of the most reliable ways to connect parts. It is used in industry and in normal daily life. Every home craftsman uses welding from time to time. It’s good if he knows how to cook himself, but he often has to turn to specialists. But welding is quite possible to learn. You should start with the simplest: electric welding for beginners is, first of all, learning how to make various seams. More complex work can be performed only after gaining experience. Let's look at the basics of technology and some of the tricks of the welding process. Where to start - the preparatory stage FIRST All you need to do is prepare the equipment. You will definitely need a welding machine, a set of electrodes, a hammer for knocking down slag and a brush. The diameter of the electrode is selected depending on the thickness of the metal sheet. Don't forget about protection. We prepare a welding mask with a special light filter, thick clothes with long sleeves and gloves, preferably suede. You will also need a welding rectifier, transformer or inverter - devices that convert alternating current into the direct current necessary for welding. Before work, it is necessary to prepare protective equipment, which includes a special mask with a light filter, suede gloves and long sleeves, as well as Necessary tools Welding process technology Welding is a high-temperature process. To carry it out, an electric arc is formed and held from the electrode to the workpiece being welded. Under its influence, the base material and the metal rod of the electrode melt. As experts say, a welding hole is formed
The modern welding process is a high technology with classification and quality criteria. Since the main final product is welding seams, they are also well described, classified and have their own quality criteria and methods of execution.
Standards in the form of GOSTs contain comprehensive information and symbols of options for a wide variety of purposes.
To begin with, let’s define the concepts of “welding seam” and “welding joint”, because some sources consider them to be one and the same thing, while others differ in the formulations.
The shortest definition: is a permanent connection by welding.
The second option reveals the physics of the welding process as such: a weld is a section in which two or more parts are connected as a result of crystallization or deformation of a substance, or one and the other together. One way or another, it is more logical to take welding seams and joints as one and the same process.
One of the oldest and most famous standards among specialists is “GOST 5264 – 80 Manual arc welding. Welded connections." This GOST was put into effect back in 1981, it still copes with its tasks perfectly: the main types of welds, their sizes, structural elements and instructions on how to correctly lay a weld are clearly listed. An excellent example of a document that does not need adjustments over time.
Types of welding joints.
Like welding methods, types of welding seams fall under a strict classification according to different criteria:
The most popular and important types of seams are grouped according to the method of joining parts:
Important! Whatever type of weld seam you choose, you need to remember and follow one simple rule: no rust on the metal! Pre-treatment with a file or sandpaper is mandatory, the issue is no longer discussed.
Classification of electrodes for welding.
Types of welded joints include both very popular methods and rare ones. Butt methods can be considered highly popular: they are used when welding sheet metal or pipe ends. The fundamental requirement for the butt method is rigid fixation of the parts to be joined with a gap of 1–2 mm, which is filled with metal during the welding process.
The most important “butt” issue is the edges of the parts that will melt and join. Or rather, the way to process these edges. The butt connection is considered one of the most reliable and economical in terms of strength. This is especially true when cooking on both sides. Preliminary preparation of the edges is an important component of a high-quality seam. All 32 types of butt joints with edge processing options are set out in the GOST 5264-80 standard.
Here are some examples:
There is no need to outline in this review all the possible methods of welding metals using the arc method, depending on the thickness of the sheets and methods of processing the edges; no one will do this better than GOST 5264-80. Therefore, the best decision would be to refer to it and recommend this excellent example of technical instructions for careful study.
In short, according to GOST, the joint family is divided into:
The T-type method is cut into the shape of the letter “T”: the end of one part is welded to the side surface of another part. Most often, the elements are located perpendicular to each other. GOST 5264-80 describes 9 T-type types: T1 to T9. For a high-quality T-joint, deep melting is required, which is performed using automatic welding. If welding, careful processing of the edges is required.
An interesting feature of deep fusion T-welds: they are stronger than the base metal. The strength of fillet welds (see below about them), on the contrary, is less than the base metal. These kinds of differences must not only be taken into account, but calculations must be made in advance. The concept of “calculation of welded joints” is included in a special section of technical mechanics, which is studied at engineering faculties.
These strength-of-materials tasks take into account the main features and disadvantages of welding joints: uneven strength, uneven heating and cooling processes, as a result, possible warping, residual stress or hidden defects.
Scheme for creating a vertical seam.
In some sources, fillet welds during welding are described as part of T-welds. They are as easy to describe as T-bars: the corner profile resembles the letter “G”, and in GOST 5264-80 they are designated with the initial letter “U”: from U1 to U10.
Despite the apparent simplicity of welding a corner joint, sometimes difficulties arise: metal flows from a corner or vertical surface onto a horizontal one. The solution to this problem is to control the movement of the electrode in order to maintain the correct angles of inclination and so that this movement is smooth. In this case, you will receive a high-quality, evenly filled seam.
An excellent way of high-quality corner welding is the method called “boat welding”: the parts are located at right angles to each other, the length of the seams is 8 mm or more.
If corner joints include sheets of metal of different thicknesses - thin and thick - the electrode should be located at an angle of 60 degrees to the thicker part so that more heating occurs on it. Then the thin metal will not burn out.
Welding fillet welds requires compliance with the rules of the geometry of welding joints.
The main geometric criteria are as follows:
Welding a fillet weld will be most optimal with a concave level shape. This is explained by the risk of incomplete welding of root fillet welds to the full thickness. When it comes to choosing the most durable option possible, there are many different factors to keep in mind.
Main types of welds.
Basic standards of electric welding for the size of the seam:
For example, as the current increases, the penetration depth increases (the size does not change). But at a time when the arc intensifies, the seam expands and, as a result, the depth of penetration decreases.
If the cross-sectional size of the welded wire decreases, the current in the wire increases, the penetration depth increases, and the seam itself decreases in size. There are many examples of the optimal combination of welding factors. All types of welded joints contain the main requirement - not to violate the execution technology, plan in advance and calculate the values of all input parameters.
Overlap joints: surfaces are parallel to each other, partially overlap each other, welded in a corner manner. These are the easiest stitches to make - a great start for beginners.
Lap joint - diagram.
All types of overlap welds have a strict limitation on the thickness of the sheet metal - it should be no more than 8 mm. Here it is important to find the correct angle of inclination of the electrode - the range is from 15 to 45 degrees. In GOST, overlap joints are conventionally designated as H1 and H2.
When working with two workpieces, one-sided turned welding is often used, which has a serious drawback: gaps form between the parts. Moisture and corrosion become the main enemies with this method. The result of this type of defect is described in one word - fragility.
However, lap joints have a very wide range of applications, here are a few examples:
Of the above options, the most reliable and economical is the butt welding method. In terms of current loads, they are almost equal to whole elements that were not welded, in other words, to the base material. Naturally, such strength is achieved only with adequate quality of work.
At the same time, it must be remembered that the reliability and cost-effectiveness of the method does not mean that it is easy to implement. Requirements for edge processing, adjustment of many factors to the conditions of a specific welding, certain restrictions in application due to the shape - all this requires strict professional discipline.
Welding butt seams.
T-joints (including corner ones) are also quite popular. They are especially often used when welding massive structures.
The simplest ones to perform are overlapping joints. They do not require processing, and general preparation is also much simpler. Very popular in welding sheets of small thickness (thickness up to 60 mm is allowed). Simplicity does not mean efficiency: excessive consumption of deposited and base metals is a common situation for such options.
The next classification criterion is the position of surfaces in space. There are four such provisions:
If it were possible to choose, experienced craftsmen would choose welding in the lower position. This is the most convenient method, and the weld pool is better controlled. A suitable method for debut works of beginners - there are practically no difficulties here. But the other three spatial options are associated with technical nuances and special requirements for execution.
When welding in a horizontal position, the main problem is gravity - because of it, the metal simply slides down. Such compounds can be cooked both from right to left and from left to right, as is convenient for you. But the rule for using an electrode is the same for everyone: its angle of inclination must be large enough. Of course, when selecting an angle, you need to take into account the current parameters and the speed of movement, everything is interconnected.
Choose, try, the main thing is that the bathtub does not tend to fall down. If the metal still drains, you need to reduce its heating - this can be done by increasing the speed of movement. The second option is to periodically tear off the arc so that the metal cools at least a little. The arc lift method is more suitable for beginners
Classification of seams by position in space.
In vertical connections, the same problem is the force of gravity, but here it is not the entire bath that tends down, but drops of metal. Usually in such cases they take a shorter arc. The seam can be welded in any direction. In the Welding Certification Regulations RD 03-495-02, these options are designated as “welding position B1” - vertical from bottom to top (this method is more convenient). “Welding position B2” is vertical from top to bottom, it is used less often, since strict control of the weld pool is required here.
The ceiling connection is the most difficult in the subgroup, which will require real skill. There are no other options in the position of the electrode - keep it only at a right angle to the ceiling. Make the arc shorter, the speed of the circular motion should be constant. In this case, the release of gases and slags is difficult, and it is difficult to keep the melt from flowing down. Even if the craftsmanship is at the proper level, and all technological requirements are met correctly, the ceiling method is inferior in strength and overall quality to welding seams in all other positions.
How are welds classified by outline:
Only experienced, certified and highly qualified craftsmen are allowed to work with industrial pipelines. Pipe connections belong to the vertical method with all the “vertical” nuances. The peculiarity lies in the angle at which the electrode is held, this is an angle of 45 degrees.
The width of the pipe seam can reach 4 cm, it depends on the thickness of the pipe itself. There are separate standards for this type of welding, for example, GOST 16037-80 describes the dimensions of seams for various connections of pipeline structures.
In appearance, newly welded seams sometimes resemble keloid scars on human skin: they are convex and protrude above the surface. Slag, scale, and drops of metal often remain on the surface. All this can and should be removed; the process is called stripping the seams.
Its stages:
The most common defect in a beginner’s work is a crooked seam with uneven filling. This picture is the result of uneven guidance of the electrode; it literally dances in the hands of the young master. Here you will need perseverance and work: with experience, all this passes without a trace. The second most common mistake is the incorrect choice of current strength or arc length, which leaves “undercuts” or uneven filling. With some defects, aesthetics suffer more, with others - strength.
Lack of penetration - insufficient filling of the joint of parts with metal. It needs to be corrected, since we are talking about the strength of the connection.
In what cases does lack of penetration appear:
An undercut is an unnecessary groove along a seam. The diagnosis is simple: choosing an arc that is too long. The treatment is also clear: either a shorter arc, or a higher current intensity.
Examples of electrode movement patterns.
A burn-through is a banal hole in a seam for the following reasons:
And here we are looking for the optimal ratio of three components: current, gap width, electrode movement.
Pores and nodules are multiple small holes. This is critical, affecting the strength of the connection.
Cracks are serious violations of the integrity of the seams. They appear after the metal has cooled and are essentially harbingers of the destruction of the seam itself. In this case, only new welding or complete removal of the old seam and re-applying a new one will save.
Is it possible for a beginner to learn how to apply high-quality sutures on his own? Yes, without a doubt. Some sources use the word “with ease.” It’s better not to promise ease, because welding has never been an easy or safe process. But it is quite possible to determine consistent and feasible steps on your own. The principle is from simple to complex. Of course, all the main types of welding joints have their own secrets and subtleties that need to be mastered.
For beginners, electric arc welding is best suited. The best option is to start studying under the supervision of an experienced mentor. But if this is not possible, there are a huge number of videos on the Internet showing all the actions and detailed explanations for them.
Single-pass and multi-pass seams.
The main initial stage is the competent preparation of the necessary equipment.
Here's what you need to prepare for electric arc welding:
The requirements for clothing are simple: it must be thick, with long sleeves and gloves. A rectifier with a transformer will come in handy (especially if the equipment is old).
The main types of welded joints are placed within the framework of a precise and clear classification with symbols and a detailed description of technological features and tips. One of the most popular standards is GOST 5264-80, which describes almost all types of welding seams.
You can learn welding on your own according to the principle “from simple to complex.” A “simple” starting point for execution is to take overlapping seams. You can finish with aerobatic work - welding with ceiling-mounted surfaces. We wish you pure metal, good orders and a working mood.
I want to know how to make welding seams correctly? What are they?
This question is quite complex and the answer needs to be given in detail. There are three types of welds - vertical, horizontal and overhead. The first is considered the simplest, the last - the most difficult. Each has its own welding technology.
Vertical seam weld
This type of weld can be performed in two ways - downhill and uphill. Uphill welding is easier to perform, since less effort has to be applied to prevent the metal from flowing down, since it will be held by the already slightly hardened metal in the weld pool remaining behind the electrode. The seam will be less neat and beautiful than when welding downhill, but for beginners this is not so important.
If you want to get an even and neat seam, then try welding downhill. This method is more labor-intensive, since you have to carefully weld the place where the parts are fastened and constantly ensure that the molten metal does not leak down. The optimal angle for vertical welding is 45 degrees.
Horizontal welding seam
This is a rather difficult weld to make; during welding, metal can flow down to the lower edge. To prevent this, it is advisable to make a bevel on the top edge. And leave the bottom one unchanged, then it will act as a limiter for the molten metal.
When welding a horizontal seam, the electrode must be held at an angle of about eighty degrees, almost perpendicular to the surface to be welded. You need to walk the electrode several times. During the first pass, you should thoroughly boil the root bead, which is done without transverse movements with a short arc.
The second roller is created in one pass at an average current strength with an electrode of a larger diameter. Next, evaluate the distance between the top edge and the second roller. If it is wide enough to accommodate two more weld beads, then make a third and fourth pass. The main task is to smooth out the depression between the last roller and the top edge.
Ceiling welding seam
This weld is difficult because it involves a huge risk of metal leaking and droplets from the upside-down weld pool. To prevent this from happening, it is necessary to use thin electrodes (no more than four millimeters in diameter) and a reduced current strength, and also periodically remove the electrode from the weld pool so that the molten metal has time to solidify in time. It is usually recommended to weld ceiling seams at an angle of approximately 75 degrees using forward movements with the electrode returning or forming a zigzag line. This allows you to keep the molten metal in the weld pool, moving the electrode away from it in time. When welding ceiling seams, it is especially important to take maximum measures to protect the welder’s skin and eyes from metal drops. When making such a seam, it is better to cover all parts of the body as much as possible, including ears, neck, and hair.
The easiest way to make welds is with equipment that allows you to smoothly regulate the current. Such equipment includes inverter welding machines. In our online store you will find household, professional and semi-professional inverters. Among the first we can recommend
Electric welding is a technology for combining the structure of metals by heating and melting with an electric arc. It has become widespread in various spheres of the national economy, including the private sector.
In fact, this method can be used to weld any metals together, taking into account the temperature of the electric arc (7000-8000 degrees). But before turning to this technology, you will have to learn how to weld a vertical seam using electric welding, and understand the technique for obtaining a horizontal seam.
The technology of welding metals is closely related to the concept of a weld. This is formed during the solidification process of metal melted by electric arc welding.
Depending on the location of the welding, the seam can be positioned horizontally or vertically. In addition, the spatial location of the seam can be bottom, side, or top.
Types of welds: 1 – horizontal in the lower plane; 2 – horizontal in the upper plane (ceiling); 3 – horizontal in the lateral plane; 4 – vertical in the lateral plane
The simplest and easiest to perform is considered to be laying welds in the plane of the lower horizon. Under such conditions, the molten metal can be controlled quite easily.
A simple weld placed in the lower horizontal plane. This is the lightest type of seam that is found in the practice of welding technology
The remaining options for the location of seams in space (side and top) are recognized as technologically difficult to implement, requiring the study of welding techniques and the development of relevant experience.
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By holding the electrode strictly at a right angle (90º), the welder ensures that work is performed in hard-to-reach places. Finally, the “back angle” technique allows for high-quality welding work on corner joints.
When installing the electrode at a forward angle, they usually work with thin-walled metals. In this position of the electrode, a wide seam of shallow depth is obtained. On thick-walled metals, on the contrary, they try to use the “backward angle” technique, ensuring the metal is heated to a sufficient depth.
The value of the current and the speed of movement of the electrode are significant factors that influence the quality of the seam. Welding with high currents is accompanied by heating of the metal to a great depth, which allows you to increase the speed of movement of the electrode. Provided there is an optimal ratio of current and speed of movement of the electrode, an even, high-quality seam is obtained.
Correspondence table for current, electrode, metal thickness
When moving the electrode at a certain speed, the magnitude of the arc power should be taken into account. Excessively fast supply of the electrode at low power will not be able to provide sufficient heating temperature.
As a result, it will not be possible to weld the metal to the required depth. The seam will simply “lie” on the surface, barely “grabbing” the borders of the edges.
Burnt metal at the point of unacceptably slow advance of the electrode. A common defect in welding thin-walled metals with a high-power arc
On the contrary, in conditions of excessively slow advance of the electrode, an overheating atmosphere will be created, which threatens the deformation of the metal on the welding line. If the metal elements have a thin structure, a powerful arc will simply burn through the metal.
You can successfully practice as a novice welder and hone your welding skills with a welder whose body is based on a metal pipe. We recommend that you read the useful information.
Welding work can only be performed if appropriate equipment is used.
Standard kit contains:
To carry out welding, you should use a working device, the electrical part of which is closed with a reliable housing. The electrical cables included in the device must have complete insulation and comply with the electrical characteristics of the device.
The welder's place must be equipped with a work table, light sources, a grounding bus, means of protection against electric shock and fire-fighting equipment.
And even before starting work, you need to carefully study, consider and study the methods and options for making connections.
We invite you to watch a video welding workshop: how to weld horizontal and vertical seams:
It is not necessary to be a qualified welder, but proficiency in welding techniques is desirable. Thanks to existing welding skills, a person has more opportunities to implement various household projects.
If you wish, you can always study the technology, and practical experience will help you master the technique of performing work at a high level.
Would you like to talk about your own experience in making welds? Do you know the subtleties of the process that are not given in the article? Please write comments in the block below.
