Corner seam: characteristics of the connection, how to weld
Welding of metal products is often used in industry and construction. Sometimes you can't do without it. The process is complex and time-consuming. In some cases, fillet welding should be used as a connection. This type of connection is considered one of the most reliable and durable. However, it is impossible to perform fillet welding without special knowledge, because during the work you need to take into account many small nuances.
Welding Features
Corner seams are quite common. It can be used to connect two metal plates or profile pipes. The main thing is that the distance between these two products is no more than 180 degrees.
In some cases, it is necessary to connect several products into one large metal structure, where the joints will have an angle of 90 degrees. All this is necessary to ensure that the structure is reliable, durable and can withstand heavy loads.
Fillet welds are quite common, especially when you need to produce a large and durable structure. Usually they contain corners that need to be carefully processed and connected. Many other techniques can be used for this, but welding is the most reliable way to connect two steel products.
This type of work has special requirements, since the strength of the entire structure depends on the quality of the seam. This type of connection is considered permanent. It can be carried out using gas equipment or other, more modern installations. The most important thing is to strictly follow the technology.
Types of seams
The corner seam is divided into the following types:
- made with overlap;
- when at the junction the edges of the products are tightly adjacent to each other;
- one edge of the product is applied to the flat surface of the other (T-seam);
- without edge cutting and with edge cutting.
Unlike conventional welding, making neat and strong fillet welds is much more difficult. The work is further complicated by the fact that welding must be carried out in different positions. Even a professional welder may have problems with his work, for example, if he needs to make a T-seam between products that are also turned upside down. In addition, the corner seam can be intermittent or continuous, short or long. A short seam does not exceed 2.5 centimeters, and a long seam does not exceed 10 centimeters.
Difficulties during welding
In order for the master to be able to carry out the most even and high-quality seam, it is necessary to know about the main defects that may arise when making a seam. Most often, a fillet butt weld turns out to be unreliable due to the fact that the material being deposited lies unevenly. Under the influence of high temperature, the metal melts and rushes down. As a result, the top edge cannot properly connect to the joint. Sooner or later, under the influence of a heavy load, the structure will collapse.
An incorrect angle can also ruin a vertical fillet weld. The two products that need to be joined with such a seam are rarely of any shape. In this case, it is very important to correctly calculate the fillet weld. Products must have the correct shape. Usually they have the same parameters (length, width and thickness).
To carry out quality work, you must carefully select the voltage parameter. If the current is too weak, it will cause the leg to be convex. This means that the base material will not melt well. Conversely, if the current is too intense, the leg will take on a concave shape. The sides of the metal product will have too deep a penetration. As a result, the design will still be of poor quality.
Preparing for work
To carry out the work as efficiently as possible, it is not enough to have good equipment, be aware of possible defects and follow safety rules. Before the master begins work, he must properly prepare the welding sides.
Basic Rules
If it is necessary to connect plates whose thickness does not exceed 5 mm to each other, then no special preparatory measures are required. If there is rust on the material, it must be removed using a special brush.
Only after this can you mark, secure the products well and begin welding. Proceed in the same way if it is necessary to make an overlapping corner weld. In order for the final structure to be strong enough, it is necessary to apply two seams on each side, one at a time.
The work becomes more complicated if you need to work with steel whose thickness exceeds 5 mm. In this case, the technician must make a slight 45-degree bevel on the attachment plate. This will create a small place where the molten metal will flow. As a result, the corner seam will be stronger and more reliable. When a master works with steel more than 1 cm thick, he needs to cut the edges on both sides. This technology helps protect the seam from burns.
After the edges are prepared and the parts are firmly in place, the specialist should not forget to install tacks on both sides. This is necessary so that during welding the seam does not warp and the metal product does not deform.
To make the structure as strong and neat as possible, welding is carried out not simultaneously on both sides, but alternately. It is important to completely finish the work on one side and then move to the other. If you do not follow this rule, the tacks may not be able to withstand the load and will most likely burst.
Fillet welding methods
During this operation, the likelihood of defects occurring is very high. Professional workers use several basic techniques, thanks to which they can obtain the most durable and neat seam. To understand how to weld a fillet weld correctly and what technique to use, you need to pay attention to the general situation and choose the most convenient welding option.
Boat method
This method is suitable for welding if the master is working with small structures that are on a solid surface, but are not fixed to it. They can be turned over. This technique is mainly used by beginners. In this case, the product is installed in the shape of the letter V. The design is somewhat reminiscent of a boat, which is where the name of the technique comes from.
The technician must hold the electrode vertically, slightly tilting it towards himself. At the same time, you should not make oscillatory movements during work. The duration of the work depends on the thickness of the metal. Sometimes it takes several approaches to make a really strong and even seam.
To give the seam the required width, the master can later perform transverse welding. Thanks to this method, the specialist has the opportunity to apply filler material on both sides simultaneously. This helps to avoid the occurrence of defects and poor-quality joints.
Down position
A specialist will not be able to fold large structures into a boat shape, so welding must be done in the lower position. The technician should tilt the electrode slightly and work at an angle of 45 degrees. In this case, you need to move it left and right. This is necessary in order to completely fill the seam.
When the master just starts welding, there is no need to make transverse movements. At the first stage, it is important to qualitatively connect the metal elements. Experts recommend making small jerks while working. This is necessary in order to slightly drive away the slag flowing onto the seam. If the master does not do this, the slag can completely block the visibility of the working surface. If the main seam is made correctly, firmly and without defects, then the following seams can be applied.
Even if the work was done efficiently by a craftsman, sometimes a weld that was made at an angle can have a sloppy and unattractive appearance. This is because the connections are often uneven. They are slightly convex above the main surface. In addition, slag residues, small scales and metal particles may be present on the seam.
Peculiarities of stripping
In order for the finished product to have an attractive appearance, you need to get rid of all this. This process is called stripping. The specialist must act in several stages. First, he uses a roll or chisel to knock off the scale, and then uses a grinder to level the surface of the seam. If the craftsman still cannot make the seam even, this can be corrected by applying molten tin to the surface.
Source: https://FB.ru/article/445826/shov-uglovoy-osobennosti-soedineniya-kak-varit
Welding corner joints: what it is, what the technology is, how to weld, a useful device
Currently, in construction and during the installation of various parts, fillet welding is very often used. Metal products connected through such a connection are highly durable and reliable.
However, fillet welds when welding require certain knowledge and skills from the person performing the work. Since the welding process is labor-intensive and time-consuming, because there are many nuances in it.
Let's look at what fillet welding is, what its specifics are and how to do it at home.
Classification of welding joints
The service life of metal structures depends on the quality and reliability of the connections. It is worth understanding that there is no welding without a seam. As a rule, it can become a weak point in any structure.
In this regard, when it comes to welding, it is the seam that is the central element that determines the quality and durability of the connection made.
Electrode position during welding.
Depending on the method of performing the work, the seams are divided:
- one-sided;
- double-sided – the connection is made on both sides of the product;
- single-layer – performed in one approach with one weld bead;
- multilayer - the number of layers in this case is equal to the number of “passes”.
Depending on the spatial location, there are welding of vertical seams, horizontal welding, and also welding in a ceiling position. Based on this, welding can be performed from bottom to top and vice versa.
According to the method of arrangement of the parts to be connected relative to each other, welds such as butt, corner, lap, tee, and end seams are distinguished.
In a butt joint, the parts are located in the same plane. This type is used in welding sheet metal, tanks, and pipes.
In angular - parts are installed at any angle relative to each other. In this case, the maximum thickness of the part should not exceed three millimeters.
In an overlap joint, the parts are installed parallel to each other so that one of them “fits” onto the other. Used in welding sheet material up to twelve millimeters thick.
In T-bars, the parts are placed normally. Most often found in load-bearing structures. The method requires careful processing of the vertical sheet.
End welds imply contact between the side surfaces of the metal being welded. The welding seam is applied to their ends. The connection is characterized by economical material and ease of implementation.
Advantages and disadvantages
Unlike other welding methods, T-joints have the following advantages:
- they form a reliable connection in hard-to-reach places;
- they do not require the use of reinforcing pads;
- used for welding workpieces of various thicknesses;
- withstand heavy load.
Flaws:
- to maintain perpendicularity, parts must be fastened before welding;
- one-sided seams are unreliable;
- when welding thin-walled parts, there is a high probability of thermal deformation;
- there is a high risk of internal defects (lack of penetration, discontinuities, craters).
Vertical seam
Welding a vertical seam can be carried out by two different methods: from top to bottom and vice versa. The easiest way to perform vertical welding is when working from the bottom up. In this embodiment, the weld pool is raised by the arc formed by the electrodes and does not fall.
When forming vertical seams from bottom to top without breaking the arc, the electrodes must be moved in one direction without horizontal displacement. In this case, an inclination of 80-90 degrees must be observed. In this case, the seam turns out almost flat.
Butt joint table.
To understand how to weld a vertical seam, you should clearly understand the sequence of actions:
- First of all, the arc is lit at the lowest point;
- a horizontal surface equal to the cross-section of the seam is prepared;
- the weld pool is held by an arc controlled by the inclination of the electrode.
In this type of work, the electrodes must move fairly quickly. Full control over the welding process is important. If the weld pool flows out from one edge, you should move to the other edge while simultaneously moving upward.
This type of connection can also be made with arc separation. This option will be especially convenient for novice welders. During the separation time, the part has time to cool. This method even allows you to rest the electrode on the shelf of the weld crater.
The pattern of movement of the rod is similar to movement without separation: from side to side, with a short roller, in loops.
It is worth paying attention to the influence of the current on the seam.
To properly weld a vertical seam, you should set the current to 5-10 amperes less than the recommended value corresponding to the selected electrode for the vertical seam and the thickness of the product. However, this statement is not always true, and in some cases the current must be selected experimentally.
You can also connect from top to bottom. In this case, the rod must be held perpendicular to the surface of the part. After igniting the arc in this position, you should warm up the metal and only then move it, forming a seam.
Welding from top to bottom is not very convenient. This type of work requires high control of the weld pool. However, with proper professionalism, an excellent connection can be formed using this method.
Main problems
An incorrect angle can also ruin a vertical fillet weld. The two products that need to be joined with such a seam are rarely of any shape. In this case, it is very important to correctly calculate the fillet weld. Products must have the correct shape. Usually they have the same parameters (length, width and thickness).
To carry out quality work, you must carefully select the voltage parameter. If the current is too weak, it will cause the leg to be convex. This means that the base material will not melt well. Conversely, if the current is too intense, the leg will take on a concave shape. The sides of the metal product will have too deep a penetration. As a result, the design will still be of poor quality.
Horizontal connections
Welding horizontal seams on a vertical surface is carried out from left to right and vice versa. In this option, the bath will drain into the lower edge. The connection technique involves tilting the electrode at a large angle, depending on the magnitude of the current.
There are several useful tips that will ensure the highest quality welding of a horizontal seam:
- It is better to place the welding seam from left to right;
- the electrode should be placed slightly back on the seam;
- the arc is lit at the lower edge and then transferred to the upper;
- the rod moves in a spiral.
If the metal flows down, you should move the electrode faster, reducing the heating of the part. The work can also be done with the arc torn off. At the moments of separation, the metal will have time to cool, as a result of which it will stop flowing. Reducing the current provides this effect.
By following the tips suggested above, you can learn how to form high-quality horizontal joints using manual arc welding.
Welding corner joints
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To achieve penetration in the corner joint (Fig. 76), regardless of the diameter of the pipe, the thickness of the metal and pipe wall, as well as the welding position in space, it is necessary to make the first bead (root corner) with an electrode with a diameter of 3 mm at a maximum current of 95-120 A depending on the thickness of the metal.
Welding the plate to a vertical pipe (Fig. 77)
Welding should be done with a backward angle. The 1st roller should be “normal” in completeness with maximum penetration and minimum cross-section.
The second roller is made with an electrode with a diameter of 4 mm at a welding current in the average or maximum range, depending on the thickness of the metal.
The “lock” of the second roller should not coincide with the “lock” of the first roller.
Depending on the specified leg, select the speed of electrode advancement. Weld without manipulation, using an arc length (short or medium). With an electrode with a diameter of 4 mm (with a medium thickness coating, brands: UONII, MP, ANO, etc.), a uniform leg on both edges in one pass can be made with a maximum of 7-8 mm. If it is necessary to make a leg of more than 8 mm, it is necessary to weld in several passes.
Place the third roller on the base, as in the lower position, achieving a smooth start of the roller. When approaching the beginning of the roller, remove the slag and, if the beginning is steep and high, perform mechanical cleaning or trimming. The stop before starting the roller should not be less than 15 mm.
Having melted the beginning of the third roller and without breaking the arc, rise to the third roller and begin to perform the fourth so that the lower edge of the liquid bath connects with the top of the third roller and forms a given seam shape (“normal” or “concave”) on the outer surface. The welding technique for the fourth bead is the same as for the third. When replacing the electrode, prepare the site again (covered from slag) for welding the fifth bead.
Depending on the depth and size of the unfilled leg between the fourth bead and the vertical wall of the pipe, welding should be performed in one or two beads. The last one - the upper roller (the fifth or sixth - should be done “normally” without undercutting on the vertical wall. To do this, it is necessary that after the penultimate roller (the fourth in Fig. 77), a minimum area remains.
The fifth roller is made almost horizontally at a welding current in the middle range with an electrode with a diameter of 4 mm or 3 mm, depending on the thickness of the metal and the diameter of the pipe and the size of the unfilled groove (unfilled leg).
Welding the plate to a horizontal pipe (Fig. 78)
The pipe is divided vertically into two sections, each section into three positions (zones):
I - ceiling
II - vertical
III - lower
Welding of each section is performed from the ceiling position. The first root roll starts from another area at a distance of 10-20 mm from the vertical axial electrode with a diameter of 3 mm at maximum current with a short arc “backwards”. Up to the vertical axial welding is carried out downhill.
Behind the vertical axial - on the rise, welding is carried out “at an angle forward” to position (zone) III. Gradually leveling the angle of inclination of the electrode to 90° along the seam, switch to welding with a “backward angle” and finish the bead behind the vertical axial by 10-20 mm.
The root roll of the second section begins from the ceiling position also from another section 10-20 mm behind the vertical axial and is performed with the same technique as the first section.
The entire root bead is performed using one welding current, of a small cross-section, of a “normal” shape, achieving penetration in the corner joint. The second layer is performed with an electrode with a diameter of 3 mm or 4 mm, depending on the thickness of the metal, the diameter of the pipe and the specified leg, at a welding current of the average range for an electrode with a diameter of 4 mm or the maximum range for an electrode with a diameter of 3 mm.
The ceiling position is performed with narrow rollers 1-1.5 wide the diameter of the coated electrode. Form the second bead on the plate and the first root bead to a position (vertical) where it is difficult to form a narrow bead at the selected welding current. The third roller is between the top of the second and the pipe, departing from the beginning of the second by 5-10 mm.
Having reached the end of the second roller, remelt its crater and perform the vertical position (zone II) with one roller across the entire width of the seam, maintaining a uniform position of the weld metal on both surfaces.
Welding across the entire width of the vertical position allows the bead to be welded using the same welding current as in the ceiling position. Manipulation of the electrode is the same as for vertical welding, only with a shift to the left when rising from the ceiling position to the horizontal axial position and with a shift to the right beyond the horizontal axial position when approaching the bottom position.
Such manipulation is necessary in order to maintain the liquid bath in a horizontal position, which contributes to the formation of a seam of the correct shape.
Weld in one pass until difficulties arise in forming a bead across the entire width (leg) on the vertical and lower surfaces. In this case, without breaking the arc, go into two (three) rollers, as in the ceiling position, only make the first roller on the pipe as a corner one in the lower position and finish it behind the vertical axial 10-20 mm of another section, maintaining the size ( leg) roller on the pipe.
Start the fourth roller a little lower by 5 mm from the moment of transition from one pass to two and complete it by connecting the top of the first with the plate, finishing at the zenith or 5-10 mm (no more) behind the vertical axial As a rule, such a roller, in to avoid slagging and to maintain the shape and size of the seam on a vertical plane (plate), proceed by manipulating the electrode as if in a vertical position, only with a shift to the right and moving forward along the first roller, maintaining the liquid bath in a horizontal position. At the very zenith of the lower position (short section on the plate), it can be difficult to dial the specified leg with the second roller. After welding the second section using the same welding technique, place an additional bead on the plate (the fifth in the lower position), if it is necessary to dial a certain weld leg.
It is recommended that an additional bead, the fifth one, be made with a 3 mm electrode, selecting the welding current as for a horizontal seam on a vertical plane. Subsequent and front layers, if a large leg is laid, should be performed using the recommended technique for welding the second layer. Welding of all types of beads is performed with a short arc.
Welding a plate to a vertical pipe in a ceiling design (Fig. 79)
The procedure for performing the rollers is the same as in the lower position.
The first (root) bead is welded with an electrode with a diameter of 3 mm with a short arc, at a “right angle” or “backward angle” - 70°-90°. In relation to surfaces - at 45°. Welding current in the maximum range.
If possible, make the second roller with an electrode with a diameter of 4 mm, like the first, selecting the welding current in the middle range.
Perform the third layer in several passes, starting the first (third in Fig. 79) on the pipe and the second roller. The roller is made as a horizontal one, with a shelf. At a distance of at least 10 mm from the beginning of the bead, it is necessary to stop welding, clean the seam of slag and continue welding in a spiral.
Using the flange of the previous bead, filling the corner along a given leg, welding is carried out in the form of surfacing, with narrow beads. The rollers between the first in each layer and the last (6th in Fig. 79) are made at an angle, like the root one. The last (sixth) is like a “normal” ceiling without a shelf.
Tudvasev V.A. "Recommendations for welders."
See also:
- Welding vertical seams
- Welding ceiling seams
Source: https://www.autowelding.ru/publ/1/1/svarka_uglovykh_soedinenij/3-1-0-492
Features of welding fillet welds
Currently, in construction and during the installation of various parts, fillet welding is very often used. Metal products connected through such a connection are highly durable and reliable.
However, fillet welds when welding require certain knowledge and skills from the person performing the work. Since the welding process is labor-intensive and time-consuming, because there are many nuances in it.
Let's look at what fillet welding is, what its specifics are and how to do it at home.
Types of fillet welds
Fillet welding is the joining of two metal products or profile pipes at an angle of less than 180°. However, bayonets are often created in metal structures where the sides are at an angle of 90°. This distance must be maintained so that during the welding process, both sides are subjected to the same load and the structure itself is more durable.
Fillet welds during welding are differentiated into several types. Stand out:
- lap joint,
- seam with edges joining at the connection point,
- a seam with one end attached to a flat plane, also a similar type of connection is called a T-joint,
- connection with and without edge preparation.
Fillet welds are classified depending on how they are laid. Based on this criterion, continuous and intermittent connections are distinguished. There are also types of seams in length: short (up to 250 mm), medium (they are formed from the point of mating of the surfaces of both metal products to the edges of the part being welded, the size of such a connection varies from 250 to 1000 mm). Long fillet welds are created with a length of 1000 mm or more.
Difficulties in the process of forming a corner joint
In order for the welding seam to be as strong and high-quality as possible, you need to be prepared for the fact that during the work you may encounter a number of defects. Let's consider the main ones:
- Undercuts. In the process of creating a corner joint, under the influence of an electric arc, depressions are formed on the surface of metal products. If we are talking about welding work carried out in the lower position, then by holding the electrode, filler material can be deposited on the damaged area. But the corner connection is much more difficult to perform and you will have to work hard to “drive” the particles of hot metal onto the side wall. Because of this, usually a fillet weld has notches on only one side.
- Formation of uncooked seam sections. Due to insufficient experience, many welders performing the fillet weld technique begin to move the end of the electrode too much to the sides in order to fill the joint. Such manipulations lead to the fact that the metal settles on the sides and the root of the seam is not welded.
- The wrong fillet weld leg was selected. To ensure high-quality fillet welding, it is important to learn how to select the correct voltage parameters and move the electrode at the required speed, without exceeding it. If the current is insufficient and the electrodes pass at a low speed, the leg will be too convex, which means the base metal will not melt well. Excessive current and high speed of electrode guidance will lead to the formation of a concave shape of the leg.
- Wrong angle. Weld joints usually have a specific shape relative to the degree of angle. The trick is to maintain the exact dimensions. If the attachment plate passes tilted to one side, it will simply ruin the quality of the design.
- Another negative point may arise in the case of uneven distribution of the deposited metal on the sides of the joint. Due to the fact that under the influence of high temperatures and gravity from the electrode and edges, the molten iron is directed downwards, the main part of the seam ends up on the bottom plate. The upper edge can only melt slightly and as a result, such a seam can immediately deform, or even completely disintegrate under load.
In addition to the defects described above, there are also some shortcomings that may arise during the work: holes, voids, craters, cracks, fistulas, the formation of solid foreign inclusions.
Preparing the sides of the seam
Note! Before you start making a weld, you need to prepare the sides and joints.
When preparing surfaces for T-joints, it should be taken into account that one of the sides of the structure being welded forms a horizontal plane, and the other - a vertical one. Thus, a right angle is formed between both planes.
For a T-shaped (T) connection, the edge of the vertical plane must be prepared based on the thickness of the sheets that are selected for welding. If the thickness of the metal sheet does not exceed 12 mm, then it does not need preparation at all.
If the thickness varies from 12 to 25 mm, then a V-shaped preparatory trim must be made on its edge. If the thickness of the workpiece intended for the vertical surface is 25-40 mm, then in this case it is necessary to create U-shaped bevels of the edges in one direction.
When the sheet thickness is more than 40 mm, the edges are beveled on both sides in the form of the letter V.
Unlike T-joints, lap corner joints do not require any edge preparation. Seams should be placed on both sides in the corners created after the metal sheets are combined, using a one-on-one overlay.
In the case of creating a classic corner connection (two connected metal parts form an angle), it is necessary to cut off the end of only one of the elements.
Fillet welds during welding. Distinctive features
The fillet welding process is characterized by a number of distinctive features. Let's consider the most acceptable methods by which corner joints are welded.
If the seam plane is located at the bottom, then it is better to weld the parts using the “boat” method. This method will allow you to get the highest quality seam and is well suited for beginners in welding work. The product is placed in a V-shape, reminiscent of a boat, hence the name of the method.
When welding with a “boat”, the risk of the formation of such defects as undercutting edges or lack of penetration is practically reduced to zero.
However, such suitable conditions for creating a fillet weld are not always present. Often, at the point where metal products are connected by means of a “boat,” T-welds are formed in such a way that one of the surfaces is strictly in a vertical position, the other in a horizontal position.
In such a situation, it is not easy to obtain a high-quality connection, because in the upper part of the corner and in the horizontal plane of the seam, the part may not be welded. Undercuts may appear on a vertical plane. The cause of their occurrence may be molten metal flowing down.
In order to avoid the occurrence of the above defects, it is important to move the electrode along the welding line with light oscillating movements.
Advice! Wire the electrode using a single seam with an 8 mm leg.
To eliminate the risk of lack of penetration, the initiation of the welding arc should begin at a distance of 3-4 mm from the edge of the leg on the lower horizontal plane. Afterwards, the arc must be directed to the top point of the seam and held there. This way you will get a well-cooked part.
To obtain a high-quality and durable fillet weld, you need to strictly adhere to the sequence of actions. Any welding machine is suitable for creating a corner joint. Do not forget about safety precautions and perform welding work in a protective suit and mask.
Source: https://svarkaed.ru/svarka/shvy-i-soedineniya/osobennosti-svarki-uglovyh-shvov.html
How to weld a fillet weld using electric welding? — Metals, equipment, instructions
Almost every person has encountered a situation where it was necessary to weld some metal part. Most often this happens during construction work.
It’s great if a man knows this process, but sometimes you have to turn to professionals in your field. But you can learn welding on your own. Beginners usually start by learning seams.
Complex work should begin only when the home craftsman learns how to weld using electrodes correctly.
Welding today is the most reliable metal connection, because it fuses materials into one whole. The procedure takes place under the influence of high temperatures. Most welding machines use an electric arc to operate.
The principle of its operation is as follows : it heats the metal in a certain small zone to the melting point. This type of welding is called electric arc welding.
When forming an electric arc, both direct and alternating current can be used. For alternating voltage, transformers are used, for constant voltage, inverters are used.
The work is easier with inverters, since they operate on a 220 V network. They are small in size and weight, about 4-8 kg. They make almost no noise and do not affect the voltage.
It is much more difficult to work with transformers, since the current is alternating, it affects voltage surges, which neighbors and household appliances are usually not very happy about. The device is large and heavy.
Thus, it becomes obvious that a welding inverter is more suitable for beginners .
Required Tools
For welding work you need a set of tools and special protection. This is the welding machine itself, electrodes, hammer and brush. The diameter of the electrodes depends on the material to be worked on.
Don't forget about protection . To protect your eyes, a welding mask is a must, and you should also wear thick clothing, suede gloves, and durable shoes. Devices that convert alternating current into direct current are also useful - this is a rectifier, inverter or transformer.
Work technology
For an electric arc to occur, conductive elements are needed: in this case, it is metal and an electrode. When metal and electrode come into contact, an electric arc appears. In the same place, the metal immediately begins to melt, and at the same time the electrode melts and is transferred to the weld pool.
Also in the process, the protective surface of the electrode burns, partially evaporating and releasing a certain amount of gases. These gases create a curtain and protect the metal from oxidation. The metal is also coated with slag, which helps the metal by maintaining its temperature.
The formation of a seam occurs when the electrode moves, which is the whole secret of welding. also necessary to monitor the angle of inclination and current parameters . After the metal cools, a slag crust remains on it, which protects the metal from oxidation. The slag is then beaten off using a hammer.
How to learn to cook
At first, welding work must be carried out under the supervision of an experienced welder; he will show you how to learn how to weld, give advice and help in case of problems. You can practice on a piece of metal.
For beginner welders, a 3 mm electrode is most suitable . It costs a little more, but is easier to work with. Later, as experience is gained, you can move on to other options. You can fix it in a special holder, which can be spring or screw and is attached to one of the cables. After fixing the electrode, you can begin connecting the cables.
The welding machine has two outputs : positive and negative. There are also two cables, one of them ends with a holder into which the electrode is inserted, the other with a special clamp.
In conventional types of welding, straight polarity is connected: minus goes to the electrode, plus to the part. But in some work, reverse polarity is used.
Electric welding process
After preparing all the parts and devices, you can start working. First of all, attach the cable with the clamp. Then you need to check the other cable for insulation and reliable fixation of the electrode. Then the current power is set on the welding machine depending on the diameter of the selected electrode.
An electric arc is ignited. To do this, you need to lightly touch the metal with the electrode , and sparks should fly out. After the first contact, the electrode touches the metal and rises to a height of 5 mm.
The height of 5 mm must be maintained throughout the entire operation. As the process progresses, the electrode should burn out and will need to be replaced . It can also periodically stick to the metal, in which case you need to shake it slightly.
After igniting the arc, you can proceed to fusing the bead. This is done with light oscillatory movements, smoothly moving the electrode. The result of the operation should be a seam with a slight deposit of metal.
Electrode movement can occur in three directions:
- Progressive.
- Transverse.
- Longitudinal.
As you work, you can superimpose one option onto another. Each master prefers to work in his own direction. After all, the main task is to reliably connect metals, and how this happens is not so important.
Some nuances
It is not enough to simply move an electrode across metal. You need to know some of the nuances of welding and how to properly weld a certain metal. One of them is that the seam “pulls” the part, which can cause them to lead.
And in the end the result will be completely different from what the master expected. Most often, this problem can be avoided by grabbing the part in several places, approximately every 10 cm.
This is done on both sides, after which the main work begins.
Electric rivet or through-hole welding
How to choose the right current
In addition to bonding the metal before welding, you need to know what current value to set in certain situations. It all depends on the thickness of the metal being worked on and the diameter of the electrode.
But sometimes the voltage may suddenly drop, the inverter itself will not be able to react to this situation. In this case, you just need to slow down the movement of the electrode to warm it up. Repeatedly running the electrode along the seams may also help. If this does not help, you can install an electrode of a smaller diameter .
Pipeline welding
Using electric arc welding, you can make a horizontal seam that runs around the circumference of the pipe and a vertical seam that runs from the side, as well as top and bottom seams. The most convenient option is the bottom seam.
Steel pipes must be butt welded, welding all the edges along the height of the walls. During operation, the electrode must be installed at an angle of 45 degrees - this is done in order to reduce sagging inside the products. The seam width should be 2-3 mm, height - 6-8 mm. If welding is overlapped, then the required width is 6-8 mm, and the height is 3 mm.
Immediately before starting work, you need to carry out preparatory procedures :
- The part needs to be cleaned.
- If the edges of the pipe are deformed, then straighten them or cut them off with an angle grinder, or simply with a grinder.
- The edges where the seam will go must be cleaned to a shine.
Source: https://spb-metalloobrabotka.com/kak-varit-uglovoy-shov-elektrosvarkoy/
Fillet Welding - How to Make the Correct Welding Seam
The technique of making welding seams (they are also called roller welds) involves choosing a mode and method of manipulating the electrode. The video on our website will show you everything in detail and in an accessible manner on how to make a welding seam correctly.
There are two types of fillet welds: T-welds (for T-shaped joints) and lap welds, both types are very common in welding. Let's look at each one separately.
Welding technique for T-joints
To get the correct welding seam, you need to place one plane horizontally and the other vertically. Welding a fillet weld must be done strictly at a right angle. If the vertical welded product is no thicker than 12 mm, then it does not require additional processing. The only thing you need to ensure is that the bottom edge of the vertical product is cut as evenly as possible, and that the joint gap does not exceed 2 mm.
In the welding structure of T-joints, all parts are important, more precisely their thickness. So, for example, if a vertical product has a thickness of 12 to 25 mm, then you need to prepare it in a V-shape. If the vertical sheet is from 25 to 40 mm thick, then the bevels of the edges need to be cut in a U-shape on only one side. And if the thickness is more than 40 mm, then a cut is made on both sides of the V-shape.
It is dangerous when a seam has one side unwelded or a corner unwelded. Therefore, in the process of welding a fillet weld, the electrode must be positioned so that it is in the plane that divides the corner in half. And the end of the electrode performs oscillatory movements so that the edges of the metal melt. It is necessary to determine in advance that the length of the welding seam is commensurate with the angle between the products.
How to apply a corner seam correctly
Welding a fillet weld depends primarily on the correct ignition of the electric arc. Ignition of the electric arc is a very important and fundamental point in welding work. The arc must be ignited immediately before starting the welding process, and re-ignited only if it breaks during the process.
The arc is excited on the lower horizontal sheet at a distance of 3-4 mm from the top of the corner, then the arc must be brought to the top of the corner and held there in order for the corners to melt better. Next, the arc needs to be raised to the height of the seam leg along the vertical product and smoothly moved back. Then, a little faster, you need to lower the arc down onto the horizontal product and bring the thickness of the seam on it to the size of the leg.
The biggest mistake is to start welding a seam from a vertical piece being welded, since the molten metal from the electrode will float onto the lower unmolten metal and block the top of the corner. In this case, penetration will not work, and it can only be detected by breaking the metal.
When the welding process is carried out with thickly coated electrodes or with increased current, a large area of molten metal is formed, which makes fillet welds impossible, because the molten metal flows onto the horizontal product, and the seam will simply turn out incorrect.
To avoid this, the products to be welded must be positioned tilted to the horizontal at a 45 degree angle, and welding must be done with a boat. See clearly how to make a welding seam - a video on our website that shows all the equipment, as well as practically how to properly clean the seams after welding.
Lap joint welding technique
This type of welding is used mainly in sheet structures. The ends of the sheets that will be welded are overlapped by a certain amount, equal to approximately 3-5 sheet thicknesses.
They need to be welded along the perimeter or along the edge of the corner seam, which was formed by covering the sheets. The positive thing about this type of welding is that there is no need to process the edges.
The negative point is that excess material is wasted and the structure becomes heavier. However, lap joints are often used.
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Source: https://swarka-rezka.ru/svarka-uglovogo-shva-kak-sdelat-pravi/
Welding fillet welds
Very often, when carrying out welding activities, it is necessary to carry out complex technical work, not least of which is the welding of one-sided fillet welds without beveled edges.
Let us note right away that such a task is beyond the capabilities of an inexperienced master; welding fillet welds requires practical care, basic knowledge and sufficient experience in this segment.
Only extensive and sufficient experience in this field allows one to determine the methods and tasks of performing fillet welding techniques.
Categories and features of connections
According to general terminology, you can find a sufficient explanation and designation of a fillet weld in the drawing, which is a mandatory attribute of the serious work of a welder. The fundamental significance of a fillet weld is the connection of two plates or two profile pipes, the angle of which is less than 180 degrees, that is, a non-expanded profile.
Very often in the welder's work you can see that the fillet weld is made at an angle of 90 degrees, as is customary in many drawings. These requirements make it possible to ensure the required level of structural stability and comply with the minimum requirements for strength and rigidity of structural parts.
The fillet welds themselves are used in welded joints, and according to regulations, such corners are of the following types:
- With adjacent edges at the same joint.
- With a butt for one edge in places where the T-shaped plane is flat.
- Stunning execution.
- With or without edge cutting mode.
Welding diagram for corner joints
It is noteworthy that GOST welding of fillet welds provides for the performance of work in different planes and in any position, both horizontal and vertical. As an example, let's take T-bar structures, which are sometimes located upside down.
In this case, it is necessary to masterfully weld a vertical fillet weld. The welding process itself provides for an intermittent and continuous approach to ensure high quality work.
There is a difference in the length of welding work, with a length of up to 250 mm, this method is called short, with a length of up to 1000 mm - medium, and above - a high method of welding fillet welds in the lower position.
Difficulties in welding fillet welds
As with any welding activity, there are certain difficulties that distinguish welding fillet welds in a vertical position according to certain criteria:
- Uneven modes of applying deposited metal to the actual sides of the metal location. There is a certain characteristic of metal under the influence of electrodes; the edge of the iron will always pull down during welding. Most of the weld joint will be at the bottom of the build plate. The upper edge of the leg of the fillet weld will only melt slightly; under a certain load mass, such an edge will easily disintegrate.
- Undercuts. An electric arc tends to gnaw out small areas of the surface of the product being processed. Ultrasonic testing of fillet welded joints in the lower position allows conditional control of the process; it is possible to hold the electrode in this position during technological operations. The electrode can be used to additionally deposit auxiliary material on the damaged area of the surface being treated. But there is a certain complexity of a fillet weld; it is very difficult to drive natural drops of hot finished metal onto the side part. In this case, processing occurs using a notch on one side of the product.
- Lack of penetration of the root area. Most often, due to inexperience, welders begin to randomly manipulate the ends of the electrode from side to side. Thus, they try to fill the joint area with deposited metal. This will only lead to the fact that welding of fillet welds into a boat will either not be completed completely, or obvious violations of the technological process will be visible. A lack of penetration defect may occur, and this in turn reduces the technical side of the design.
- Incorrect position of the leg. In this case, the leg of a fillet weld is the area on which the general principle of butt welding depends. Here you will need to empirically select the required speed of movement of the electrode, as well as adapt the operation of the welding device, according to general control principles. Weak current readings will lead to convex fitting of corner joints of welded joints, which directly indicates poor penetration of the main components of the metal joint. Strong, excessively high current levels, on the contrary, will lead to a concavity in the thickness of the fillet welds, or a negative leg angle will appear. On the one hand, high current creates a complete welding pattern for a corner joint, which visually seems ideal and of high quality, but in fact, high loads will lead to destruction of the joint, and this, in turn, is fraught with serious consequences.
- Incorrect connection angle setting. Welding structures rarely have deviations in one direction or the other. To minimize these phenomena, semi-automatic welding of fillet welds is carried out exclusively according to the specified drawings, where no deviations are allowed unless an arbitrary angle is provided for the joint design. This problem is most often typical for structures where clear connection angles are provided at 90.45, 135 degrees.
Undercut and lack of penetration of the weld
The above defects are the most common for submerged arc welding of fillet welds. There are also such uncharacteristic defects as holes and voids in the metal structure, the presence of solid inclusions, the appearance of cracks at the border of the base and seating material, and there are mixed characteristics of the shaped weld.
Preparatory work
Here it is necessary to timely prepare materials and tools for welding operations. If the plate has a size of up to 5 mm, then there is no need to carry out preparatory operations to ensure control of fillet welded joints. For all other cases, preparation is mandatory.
"Important!
If a metal product has effects in the form of rust or contamination, it is enough to clean them with a special brush.”
Next, we establish the working markings, installation and carry out the installation of the U4 weld. This option is also applicable in the case of overlap welding.
If the thickness of each edge is greater than 5 mm, then a single-sided edge cutting task will be required. We install the bevel at 45 degrees on the existing attachment plate. This will ensure the necessary flow of the volume of molten metal and ensure high strength parameters of the product.
For metal with a thickness of over 10 mm, sharpening is necessary on both sides of the metal product. This will ensure two-way flow of molten metal.
It is advisable to leave the cone of the plate being processed blunt; this increases the rigidity of the structure as a whole when carrying out basic welding work.
Welding is carried out in stages on each side, using the working torques of the tack. Thus, it is possible to ensure high rigidity parameters of the product. Tacks will help get rid of distortions and other negative phenomena that are typical for fillet welded joints. We correctly choose the welding method, which is represented by a “boat” limbo, or in the lower position.
welding fillet welds in practice
Source: https://svarkaipayka.ru/tehnologia/drugoe/svarka-uglovyih-shvov.html
How to weld a fillet weld using electric welding
Almost every person has encountered a situation where it was necessary to weld some metal part. Most often this happens during construction work.
It’s great if a man knows this process, but sometimes you have to turn to professionals in your field. But you can learn welding on your own. Beginners usually start by learning seams.
Complex work should begin only when the home craftsman learns how to weld using electrodes correctly.
Welding today is the most reliable metal connection, because it fuses materials into one whole. The procedure takes place under the influence of high temperatures. Most welding machines use an electric arc to operate.
The principle of its operation is as follows : it heats the metal in a certain small zone to the melting point. This type of welding is called electric arc welding.
When forming an electric arc, both direct and alternating current can be used. For alternating voltage, transformers are used, for constant voltage, inverters are used.
The work is easier with inverters, since they operate on a 220 V network. They are small in size and weight, about 4-8 kg. They make almost no noise and do not affect the voltage.
It is much more difficult to work with transformers, since the current is alternating, it affects voltage surges, which neighbors and household appliances are usually not very happy about. The device is large and heavy.
Thus, it becomes obvious that a welding inverter is more suitable for beginners .
Welding fillet welds: features of joints and their types, technology
Fillet welding joint is a type of connection between two metal parts that are located at an angle to each other. Most often this angle is right. Additional strength when welding at right angles is provided by the same load on both sides. The welding of the fillet weld determines its shape. It can be flat, and also have a sphericity - convex or concave.
The scope of application of fillet welds is construction, mechanical engineering, bridge construction, infrastructure, joining parts in metal furniture. The welding method ensures the reliability and durability of structures.
Types of seams
Fillet welds during welding, depending on their characteristics, come in different types:
- overlap;
- butt;
- T-bars;
- end;
- corner.
Connections can be: without bevel of edges, with bevel of one edge, two bevels.
There are similarities between the T-bar and corner types. A T-weld is made by applying the end of one part to the surface of another so that the configuration is an inverted letter “T”. The difference between a corner connection and a T-joint is that the joining in the corner type is carried out so as to form the letter “G”.
In fact, a fillet weld is a type of T-weld. The requirements for their welding are no different. The subtlety is that if parts of unequal thickness are connected, then an inclination should be made towards the thicker one. Then more heat will be applied to it and the likelihood of burning a thin part will be reduced.
A corner lap joint forms an angle, one of the sides of which is the end of one of the parts. The classification of fillet seams also depends on the length, method of laying, number of sides and layers. Depending on the direction they are vertical and horizontal. In addition to a continuous seam, an intermittent seam is used, when it is performed in separate segments and even pointwise.
Preparatory work
Before starting fillet welding, preparation is carried out. If, during a visual inspection, dirt, scale, or rust are observed on metal parts, then they must be cleaned. Particular attention is paid to the welded areas. For these works, brushes with metal bristles, solvents, grinding tools and blowing with compressed air are used.
A corner welded joint will be more reliable if you trim the end that is supposed to be connected to the surface of the second part. When installing elements, it is advisable to use tacks on both sides. This prevents the occurrence of distortions and deformations. Before starting the process, you need to choose the electrodes wisely. This depends on the thickness of the metal sheets and the number of layers.
Welding technology
A high-quality connection for a fillet weld can be obtained using a boat installation. This is explained by the fact that when placed on a horizontal surface, liquid metal will begin to flow down. This does not happen with a boat stitch, and the seam will not have defects for this reason.
The method got its name from the shape of the stand in the form of the letter “V”, reminiscent of a boat. With any method, the location of the electrode must be such that the arc reaches the edges of both parts, which is ensured by its correct inclination.
Conventional equipment is suitable for welding corner joints. You can use a simple transformer welding machine. The disadvantage is the large size, which causes problems when moving. A more mobile option is an inverter. It is small in size and weight, and has different modes. With its help, arc stability is achieved.
The current is adjusted in direct proportion to the diameter of the selected electrode and the thickness of the products being welded. At higher values there is a risk of burns, and at low values the electrodes may stick. The movement of the electrodes during fillet welding can be oscillatory, which gives excellent quality of the seam.
Other movements are also allowed: in different directions horizontally, in the upper and lower positions.
It is possible to make a ceiling seam if it hardens quickly. For this purpose, electrodes having a refractory coating are used, and welding is performed in a circular motion. This position is uncomfortable for the welder. In addition, if the electrode moves away, the arc immediately goes out, the metal cools, and a decrease in the weld pool threatens a short circuit. Warming up the welding site from below also creates difficulty, so if possible, it is advisable to resort to other options.
When placing a fillet weld when welding at the bottom, the boat method is preferred. It is much easier to perform it in this position than at the top, and the result will be of higher quality, and the risk of lack of penetration and cutting of edges will be minimal. When welding pipes for joining, the socket method is used, which requires a centering device.
A particular problem is posed by fillet welds, welding of which must be carried out in places where access is difficult, in particular when joining pipes. In this case, the following tools and consumables are needed:
- special soldering iron;
- additional nozzles;
- cutter;
- degreasing solution;
- connecting elements.
The pipes are melted with a soldering iron, and their individual elements are connected using nozzles. If a vertical seam is to be made, it is necessary to ensure the fixation of the workpieces. In several places, transverse bridges are used for tack purposes. You should move from bottom to top, using the method of inclined electrodes. Molten liquid dripping down can result in poor performance.
After the process is completed, frozen drops and splashes, as well as scale, usually remain on the welded surfaces. Final processing required. It is done using a chisel and a hammer. In addition, it may be necessary to level the convex surface of the seam. This is done with an angle grinder.
Arc initiation
The first time the arc is ignited is before the welding process begins. Then this must be repeated every time it goes out. You can initiate an arc by touching the electrode to the surface of the metal being welded and quickly moving it back. If this action is delayed, the electrode may weld to the surface. In this case, you will have to tear it off by sharply turning in different directions.
You can also quickly run the electrode over the surface or tap it. The quality of welding largely depends on the length of the arc. At the optimal value, a characteristic crackling sound appears. An arc that is too long will burn with a hissing sound and will not produce enough depth.
A short arc is good for vertical welding. Too short threatens to cause the electrode to stick. If it is necessary to take a new electrode or the arc extinguishes prematurely, it is necessary to re-ignite it, first removing scale from the seam. Throughout the entire process, the arc length must be constant.
Possible defects
A corner weld has certain difficulties in its execution. This increases the risk of defects in the form of undercuts, uncooked areas, incorrect angles, the formation of cracks, voids, holes, and foreign inclusions. After completing the process, it is necessary to carry out visual inspection and resort to other known methods of identifying defects.
Interesting video
Source: https://osvarka.com/shvy-i-soedineniya/svarka-uglovykh-shvov
Corner seam. Mistakes of a novice welder and their correction
Many amateur welders perform fillet welds with gross errors. This especially applies to novice welders who are just learning this skill. Some time ago, based on a photograph sent by one of my readers, I wrote an article where I examined the errors of performing a weld in the down position. If you haven't read it, read it.
Now, based on a photo from the same reader, I will analyze his fillet weld. In general, a combination of many mistakes leads to this result, but I will still try to structure my story.
So, let's go.
No metal at the top of the corner
The most basic and conspicuous defect is the absence of weld metal at the top of the corner, i.e., at the junction of the parts. In photo 1 I have outlined this with red ovals.
Photo 1. No weld metal at the top of the corner.
This occurs as a result of incorrect movements of the electrode. In particular, the rapid movement of the electrode at the junction of the parts (at the top of the corner) and prolonged retention on the sides of the seam.
Also, such a defect can also be caused by an incorrectly selected electrode diameter. The fact is that an electrode that is too thick can touch the parts with its edges, so the arc, which always follows the shortest path, will not “reach” the top of the corner. Read more about lack of penetration of a fillet weld here: http://www.elektrosvarka-blog.ru/uglovoj-shov-neprovar-1/
In general, in this situation it would be possible to finish listing the errors, because Against the background of such a gross defect, everything else does not matter much. But let's imagine that there is still metal at the junction of the parts (at the top of the corner).
Then in photo 2 it makes sense to pay attention to the fact that there is significantly less metal on the vertical wall (yellow arrow) than on the horizontal surface (blue arrow). And on the right side of the seam there is no metal at all on the vertical surface (yellow oval), while on the horizontal surface there is quite a lot of it (blue oval).
Fillet weld with different amounts of deposited metal
Photo 2. Different amounts of deposited metal on the vertical and horizontal walls.
This phenomenon occurs when the electrode is at the wrong angle to the workpiece, and the welder does not monitor how much metal is supplied from the electrode to each side of the weld.
Besides this, I see a few more blots, but in this situation they are not at all important.
In fact, the topic of making fillet welds is much broader than it seems at first glance. The fact is that a fillet weld can be placed in different ways in space and welding in each position has its own characteristics. In addition, welding the corner inside and outside also has its own characteristics (correct relative position of parts, gaps, etc.). And, unfortunately, this cannot be conveyed in articles - you need to watch the video.
More on the topic:
Reasons for lack of penetration in fillet welds. Part 1
Errors when making welds
Thin metal, vertical seam
courses:
How to cook with electric welding
How to set the welding current correctly
How to choose a chameleon mask
How to set up a chameleon mask correctly
How to choose a welding inverter
Source: http://www.elektrosvarka-blog.ru/uglovoj-shov-oshibki/
