How to weld vertical pipes

Welding of fixed pipe joints (horizontal, vertical), technique and features

The preparatory stage is often more important than the work itself. Preparation for welding non-bending (non-rotating) seams is no exception.

Take a suitable tool and clean the welding area from all unnecessary debris, rust, paint residues. Then cut the pieces using a power tool or the thermal method, while keeping them together.

Based on the dimensions of our pipes, tacks are used to fix the workpieces, which resemble a welding seam.

Introduction

Be sure to ground metal parts such as the welding table, transformer base and other non-insulated devices.

Use electrical wires and cables with insulated coating. After welding the fixed pipe joints, take a hammer and chisel and remove any remaining slag. Then, if necessary, the seam can be smoothed with a grinder.

At the moment, 3 main methods of welding metal fixed fragments are used, which fundamentally determine the concept of operation of each of them:

• In a horizontal position;
• In a vertical position;
• At an angle of 45 degrees.

The choice of a specific method for welding fixed pipe joints must be based on:

• wall thickness;
• pipeline location;
• placement angle during welding.

Combining pipes using a three-layer seam is used if the thickness is 12 mm. Each seam should be no more than 4 mm high, and the width of the seam bead should be no more than three diameters of the conductor.

As the name suggests, rotary pipes can be rotated in the desired direction, making the welding process of non-rotating pipe joints easier and there will be no need to create complex seams (for example, ceiling ones).

How to weld a horizontal joint

Unlike other technologies, there is no need to completely cut the welding edges of non-rotary joints. All actions are performed using arc welding.

It makes sense to leave a slight ten-degree groove, which will allow not to lose the quality of welding seams and simplify the process of combining pipes. A horizontal seam can be made either from right to left or from left to right, choose whichever is more convenient for you.

We recommend layer-by-layer application of narrow seams on horizontal pipes. First, use a welding roller to weld the base of the seam; the diameter of the conductor is taken to be 4 mm.

According to Ohm's law, the current is set in the range of 170-190 A. Perform repeated back-and-forth movements with the conductor until a thread-like welding bead 1.5 mm high is formed at the place where the pipes are combined.

At this point, two coatings are made on the interlayer of the welded joint of the fixed joint, the first is carefully cleaned, and the second is applied to the first, while the conductor produces slight vibrations between the lower and upper edges.

Make the second layer in the same direction as the first. The third layer should be performed in high current mode (up to 300 A), its direction should be opposite to the directions of the previous layers.

The angle of inclination of the electrode is selected large enough so that the weld pool does not tend downward. It is also recommended to use an electrode with a diameter of 5 mm, which will significantly speed up the welding process.

Welders use three electrode positions when welding fixed pipes: “backward angle”, “right angle”, “forward angle”. In the described method, it is recommended to use the first two. The third weld bead is filled to 75% of the second.

The fourth roller is performed in modes similar to the third, but its direction does not change. Apply the conductor to the vertical pipe at an angle of 80-90 degrees.

If the metal flows down, we recommend reducing the current a little and making the passage faster with the electrode. You can also break off the welding arc for a short time so that the surface has time to cool a little.

So, when welding horizontal seams of non-rotating joints using three or more welding layers, perform each layer, starting from the third, in directions opposite to each other.

For structures with a diameter of less than 200 mm, the continuous seam welding method is used. For products with a diameter of more than 200 mm, use the so-called reverse-step method. We recommend making the length of each finished pipe section no more than 300 mm.

How to weld a vertical joint

Welding non-rotating vertical seams is similar to the above described method for welding horizontal joints. The difference is that during welding you need to inspect the weld pool and periodically change the angle of the conductor.

Welding must be done using short arc welding. The basic principles of the technology for welding fixed vertical joints are as follows:

1. The position of the electrode should be “at a right angle” or “at an angle back”. The welding edges of fixed joints need to be filled very quickly.
2. The boundaries of adjacent welded layers are made with a shift of 5-10 mm from each other, and depend on the diameter of the product.
3. The main seam of a fixed joint is welded in several layers (often two). Depending on the thickness of the pipe wall and the distance between the combined pipes, the current mode and the overall speed of the welding process change. Good quality of the seam is ensured by maintaining the welding layer in a liquid state while welding the weld bead onto it.
4. The front layer is fused with narrow beads. In the case when the electrode moves up and down without separation, the seam will be flat.

How to weld a joint at a 45 degree angle

When using this technology for non-rotating joints, the weld will be obtained at an angle. The seam should be filled evenly.

The angle of inclination of the electrode and the direction of welding in this case are constantly changing, which significantly increases the complexity of the work, and, therefore, is performed by professional welders.

And if it is necessary to make the weld of a non-rotating joint completely sealed, the working conditions become even more complicated.

The diameter of the corner pipe you are welding directly affects the choice of a specific welding method:

1. If the pipe diameter is 200mm or less, the multi-layer welding method is used. To ensure that each layer is applied correctly and evenly, during the welding process the pipe is gradually rotated along its axis.
2. To work with pipes with a diameter of more than 200 mm, they are divided into several identical segments around the circumference and each segment is worked separately. When the first two segments are ready, the pipe is turned half a turn and welding continues on the remaining two.
3. In the case when the diameter exceeds 50 cm, the pipe is also divided into segments, but their number is much larger. In general, the size of one segment should not exceed 300 mm.

Source: https://prosvarku.info/tehnika-svarki/kak-varit-nesgibaemye-styki-na-trubah

Welding pipes using manual arc welding - electric welding

How to weld pipes is necessary knowledge for every owner and home owner. Since this process is gaining high popularity due to the strength and reliability of the connections.

Today there is a wide range of welding devices for household and industrial use on the market. Plus, the process is do-it-yourself, so many can do the work themselves at home.

In our article we will look at how to properly weld pipes.

Varieties of welding methods

Today there is a huge classification of types of welding for copper pipes. Visually, the branching looks like this:

• The thermal group includes such methods as gas, arc, electron beam, plasma, laser, etc.
• The thermomechanical group are methods that operate using a magnetic arc and resistance welding.
• Mechanical group - the purpose of connection is achieved through explosion and friction.

Depending on such a criterion as the type of energy carrier, welding methods are:

• Arc;
• Gas;
• Plasma;
• Laser.

There is such a branching of methods by which connections are formed:

• Forced method of connecting elements of water pipelines;
• Free creation of a seam by welding.

If we consider the classification according to the method of protection, then there are the following types of welding:

• The connection is made using a wire with a protective electrode;
• Welding of water pipelines is carried out with shielding gases;
• Flux welding of components.

From the literature and videos we studied, we learned that according to GOST for main pipelines it is necessary to make connections using arc methods. In most cases, automatic arc methods are used under flux components. If it is not possible to use mechanical means, then it is necessary to use manual techniques. It is worth noting that this technology can be performed for vertical, bottom and ceiling joints.

Attention! Electrodes for welding pipes in the manual version move around the circumference at a speed of up to 20 meters per hour, and in the automated process - up to 60 meters per hour.

Manual arc welding of pipes with protection gases is used to organize pipe connections in spaces.

Preparatory work for welding

Before starting installation work, you should determine whether the materials comply with GOST and have quality certificates. It is also necessary to select parts that do not contradict the design and technical specifications. The ends of the connection parts must comply with the welding processes. If this norm is not taken into account, then processing must be performed mechanically.

For pipes with a small diameter, you need to use a trimmer, a chamfer, grinding machines, and devices for cutting steel products. For large quantities – milling and grinding machines. In order to make the clearance correctly, you need to use the following thermal techniques:

• The edge can be made by gas-oxygen cutting using an abrasive wheel;
• From numerous literature and videos, we learned that it is possible to use the air-plasma method with further processing at depths of no more than 1 mm;
• GOST allows the use of the air-arc method at a depth of 0.5 mm;
• Special cutting electrodes can be used which eliminate the need for further grinding.

Attention! Before cooking pipes, it is necessary to clean the inner walls of various contaminants.

Perform preheating

Recommendations and video provide for preheating. It should be noted that according to GOST, this action is mandatory. The characteristics and components of the weld joint are based on the cooling rate of the steel in the temperature range from 500 to 800 degrees. If this happens quickly, then hardening structural elements that have ductility and strength can be formed.

Attention! If you initially heat the thickness of the device wall, you can control the rate at which the temperature drops.

If the area is heated correctly, the risk of obtaining hardening structures can be reduced, which promotes the activity of hydrogen diffusion evacuation from the zone and seam. Such a connection will increase the level of welding resistance and protect against possible damage to the integrity of the surface. In order to select a temperature that complies with GOST, you need to keep in mind several factors. Such as:

• Chemical components of metal;
• The thickness of the pipe walls;
• Type of electrode coating;
• Temperature conditions of the area.

After looking through a large amount of literature and videos, we found out that for preheating we only need one tool - an electric or gas type device. It is worth noting that the process must be carried out over the entire area of ​​the product. The width of the heating perimeter from the seams is more than 7.5 cm.

Manual arc welding technology

In most literature and videos, most often when there is a large number of jobs, everyone often uses the manual or arc method. It is correct to form the lumen of sections or individual elements into an unbreakable thread. In order to calculate electrodes when performing welding, you need to take into account the mass of the metal and the brand of the electrode.

The method by which the welding is performed gives impetus to the determination of the material to be joined. Based on the conditions of use and the grade of steel, it is necessary to select components to perform the work. After this, we install the equipment and draw up a work plan. Worth considering. What needs to be taken into account is the speed of construction work.

Attention! Sometimes the choice of material directly depends on the dimensions of the wall and the diameter of the product.

According to GOST, if the wall thickness is no more than 6 mm, then an overlay of at least a couple of seams is required, otherwise more than three seams. The gap must be thoroughly melted, forming a reinforced return roller, up to 3 mm thick for the internal seam.

Important! From the video tips, we can highlight the recommendation regarding the external area, it should have small scales and a smooth surface.

The welding process with a diameter of more than a meter involves preliminary work inside the pipe, in the place where the clearance is located. It is worth considering that this must be done after placing the root sutures. In addition, you need to weld the lower part of the circumferential joint area.

The seam layer that is filled must be reliably fused with similar elements. By the way, you need to process the edges of the pipes that are welded. After completing the layers, it is necessary to clean the areas from slag contamination of the seams. This standard must be complied with without fail, in accordance with the requirements of GOST.

The central seam should have smooth outlines and a connection with the surface of the pipeline. This work must be completed without any cuts or damage. Reinforcement of seams should not exceed 3 mm. The cutting width overlaps by 3 mm in both directions from the center. Today, video consultants identify three welding schemes, which differ in the types of electrodes used:

• Welding joints with an electrode with a main coating;
• Connection with a gas-type electrode based on gas;
• Works based on hot passing and containing a gap in the electrode seam.

As we found out, welding pipes is an important and necessary process that requires precision execution and compliance with the standards and requirements of GOST.

Source: https://vodakanazer.ru/truboprovod/kak-svarivat-truby-iz-metalla.html

How to weld a vertical seam with an inverter: how to properly weld a seam using arc welding with electrodes

When studying a welding machine, a beginner may think that now he can easily weld a vertical seam with an inverter. But in practice, everything may seem much sadder: from the inside out, the product turns out to be deformed, and if the current strength is not adjusted correctly, the thin metal will crack.

Don’t get upset ahead of time and quit this useful activity. Our tips will help you learn how to weld a vertical seam using arc welding.

Vertical welding

In cases where it is necessary to fasten two metal workpieces together in different planes, the vertical welding method is used. The method is complex due to its differences from conventional ones, so some technological methods do not work in it. This happens because in such a position difficulties arise due to the parts sliding down under the influence of gravity. Therefore, the welder needs to apply maximum technical skills based on correct knowledge.

This type of work is used in the manufacture of pipes. The vertical is the main way to do this. By practicing on an unnecessary piece of metal, you can quickly gain experience, but first you need to properly prepare informationally.

First, a beginner needs to master the rules of handling a welding machine, which will ensure easy ignition of the arc and its stable combustion. Basic Rules:

1. Semi-automatic welding. This method achieves good quality. If you configure the device correctly, it will turn out smooth and without breaks. For some, the need to use gas cylinders is considered an inconvenience.
2. Electroslag method. This welding occurs by heating the melting zone of the slag pool. This method allows you to weld metal of any thickness.
3. Electric is now the most convenient device. Having learned how to handle it, welding a vertical seam with such an inverter will be easy for beginners.

Each of these ways of performing vertical welding is good. However, to achieve results, many more requirements will need to be taken into account.

Conditions for a high-quality vertical seam

In order for the seam to turn out correctly, it must:

• be highly durable;
• made with high quality;
• look aesthetically pleasing.

The most common mistakes are:

1. Incorrect positioning of the rod during operation. It must be perpendicular, otherwise an angle will form and the arc will become unstable.
2. In cases where the welder needs to weld a vertical seam using arc welding, the arc length is not observed. When it is too long, smudges form.
3. Tilt of the rod to reduce the number of smudges. Thus, the entire technological process is disrupted.

It is recommended not to forget to follow these useful recommendations:

• you need to prepare your product: sand it, remove dirt from it, get rid of any remaining oil, rust or paint;
• if it turns out that the appearance of smudges is inevitable, slightly increase the current strength along with the width of each seam.

Vertical seam production technology

Let's consider the conditions for controlling an electrode powered by an inverter during the cooking process. The main advice for this is:

• Work can be done in two ways: from bottom to top, from top to bottom;
• install the electrode perpendicular to the work site, touching it with the corner forward.

And also use the following directions with the end of the rod, depending on the width of the seam:

• wide: in a semicircle (circle, drop or loop) from left to right, the seams are placed on top of each other according to the established direction;
• narrow: with upward segments, the beginning of each subsequent one overlaps the middle of the previous one;
• or other widely used ones: herringbone (if the gap between the parts is 2-3mm), triangle (gap less than 2mm), ladder (when the distance is maximum).

Young workers are often interested in the question of the duration of pressing the electrode rod on the surface to be welded. In this case, experienced welders recommend saying to yourself the number twenty-two with each press of the machine. This is exactly how much time it will take and you need to not tear the electrode off the metal sheet. And from this it follows that for thick metal you should speak more slowly, and with thin metal a little faster.

The number of Amps installed on the inverter is important to the bottom line.

For example, it would be most effective to use the following scheme: install a power of 30A for each one millimeter of the electrode taken. If the technology and thickness of the product allows, you can deviate slightly from these numbers, but it is better not to do this, because:

• when the force is weak, the seam will not be very aesthetically pleasing, the sludge will accumulate in a large layer at the top;
• if, on the contrary, it is too large, there is a possibility of burning through the metal.

How to cook a vertical seam

When starting welding, you need to familiarize yourself with the sequence of each of the required manipulations:

• make an overlap at the bottom of the prepared surfaces;
• You should always start not with the prepared overlap, but a little higher. This way, you won’t have to correct everything if you make a mistake;
• It is best to cook without tearing off the arc;
• after turning on the device, after each press say 22 to yourself and begin making a new seam;
• after finishing, clean the surface from the outside and inside of the formed slag and, if necessary, proceed to weld the reverse side in the same way.

These tips will help you master vertical welding, even if you are new to welding. A little training and you will learn how to weld seams like a professional.

Source: https://TehnoPanorama.ru/instrumenty/kak-varit-vertikalniy-shov-invertorom.html

How to cook pipes: useful tips for beginners

How to cook pipes: useful tips for beginners

It is not easy to weld pipes, as evidenced by the many questions on forums from novice welders. In addition to the correct selection of consumables and welding mode, pipes require careful fitting and high-quality cleaning of the metal surface. Only in this way will it be possible to achieve an aesthetic, and most importantly, durable connection that will not leak.

That is why only the best specialists with special permission are allowed to weld pipelines, especially under pressure. As for beginners, they first need to comprehend the very basics, which will be discussed below, in this article from the website mmasvarka.ru.

What electrodes are best for welding pipes?

For welding steel pipelines, it is better to choose only the highest quality and time-tested consumables. In this case we are talking about electrodes, on the quality of which too much depends.

The best models of electrodes for welding pipes are rightfully considered:

• UONI electrodes make it possible to obtain a high-quality welding seam, although they require a stable arc in operation and a low welding speed. Nevertheless, UONI electrodes are attractive to both professionals and beginners, primarily for their welding quality.
• Electrodes ANO-21 and 24 - you need to work with these electrodes on alternating current. These models of welding electrodes are very popular when used in everyday life; they allow you to weld various types of structures, have a low cost, and are also capable of providing a high-quality weld.
• MP-3 electrodes are rightfully considered one of the best electrodes for welding steel pipes.
• Electrodes LB-52U - from a Japanese company, have also proven themselves well for welding metal pipes. They are able to provide arc stability, a strong and aesthetic welding connection.

Be that as it may, the success of welding metal pipes depends not only on the quality of consumables.

Much, of course, depends on the skills and experience of the welder. And since novice electric welders do not have it, questions arise, such as: how to weld pipes, and what methods of welding exist.

Methods of welding metal pipes

There are several ways to obtain a high-quality welded pipe connection. Much depends on where exactly the pipes will be used. If this is a pipeline and complete tightness of the connection is required, then one method is applicable; for installing greenhouse supports, for example, a completely different one.

There are several ways to cook pipes:

• Butt welding - this method of welding pipes is most common among welders. When performing it, the pipes are located in front of each other with little or no gap. In this case, it is very important to carefully adjust the pipes so that their edges are absolutely even.

• Overlapping - the method is applicable for welding pipes of different diameters, when one pipe is put on another. This is the simplest method of welding metal pipes to each other, which is distinguished by its simplicity and speed of implementation.

• T-joint - this pipe connection is necessary when it is necessary to maintain an angle of 90 degrees between the pipes.

• Corner - the connection is used in cases where the angle between the pipes is less than 90 degrees.

For beginners who have just started welding pipes, there are a few simple tips that will help you weld metal pipes efficiently and without errors.

Weld metal pipes with T-joints or butt joints, best with electrodes of at least 3 mm. In this case, it is recommended to set the current on the welding machine from 80 to 100 A. When welding pipes with overlaps, the current on the inverter should be increased by approximately 20 A.

At the moment when the welding seam is filled with liquid metal, it is recommended to control its rise above the surface. In such cases, the welding seam will turn out beautiful and even. The height of the weld seam above the surface of the pipes should be around 2-3 mm.

When welding a profile pipe, it is first recommended to use a spot connection method, rather than welding the entire pipe at once. First, one side is tacked, then the other, and only after that, the profile pipes are completely welded.

It is very important that when welding pipes, the seam remains continuous. It must end in the place where it began. This will serve as the key to a reliable, and most importantly, hermetic connection, because welding metal pipes, in most cases, presupposes a complete tightness of the connection.

Source: https://mmasvarka.ru/kak-varit-truby.html

How to weld a pipe to a pipe perpendicularly

The reliability of metal structures depends on the quality of welding work. Therefore, there are state standards that regulate welding processes.

For example, GOST 23518-79 determines what should be the connections of parts welded in a shielding gas environment, and how to weld at an acute or obtuse angle. Depending on the gas used, the type of electrode, and additive, the requirements for the welding process are established.

To comply with the technology, devices are used that prevent parts from changing their position, making the welder’s work easier. Such devices help maintain a right angle or any other.

Electrode tilt

To weld parts at right or acute angles, you must be able to move the electrode correctly. During the welding process, the end of the electrode melts along with the coating, which releases protective gases and partially turns into slag, which also protects the weld pool from atmospheric oxygen.

It is necessary to ensure that the bath is constantly covered with liquid slag, otherwise a high-quality weld will not be obtained. The metal must remain in a liquid state for at least three seconds, which is required to release harmful gases.

In this case, it is necessary to move the electrode along the seam, making complex rotational or zigzag movements with the end of the electrode. Such control over welding can only be achieved with the correct angle of inclination of the electrode. But the tilt angle is needed not only to control the welding progress. It can be used to influence the characteristics of the weld.

Welding at an angle forward makes the penetration depth smaller, while the width increases. This can be used when welding thin metals. With this method, the edges are well fused and the welding speed increases.

When welding at an angle backwards, the penetration becomes deeper and the seam is higher, but the width decreases. The edges do not warm up enough, so lack of penetration and the formation of pores are likely.

But the ability to cook is not enough to obtain a high-quality weld. Sometimes a certain position in space is required to make a good seam.

And this is achieved by using special devices that fix the parts to be welded in space as required by the welder. For example, when electroslag welding it is required to position the seam vertically.

When welding, it is often necessary to secure the parts to be joined together so that the welder can do his job. If the products are heavy and have complex shapes, then you cannot do without special devices.

In small workshops, universal type devices have become widespread, capable of fixing the assembled product before welding and changing its position during the work. They come in installation and fixing types.

Installation and securing mechanisms

More practical to use are mechanisms that perform both functions at once - secure and install the workpiece in the required position. In this case, the part is simply installed in the fixture and clamped. Next comes the welding of the workpieces.

The simplest device in design is a device for welding perpendicularly connected products. The base of the device is mounted on a welding table.

If these are large products, then a lattice frame is made and placed in a horizontal plane. The products to be welded are placed on its surface at right angles to each other. For this purpose, there are guides in the form of corners on the plane.

If you need to weld one or more products at right angles, you can fix them using screw clamps (clamps) . It is easier to start welding any connections at right angles on a welding table.

When laid on the table, the correct arrangement of the parts in one plane is guaranteed. A corner rectangular clamp helps maintain a right angle between the parts. The parts are secured in several places by welding, after which the whole product can be rotated as needed for the next operation.

When welding volumetric products, it is necessary to make rotary clamps. This speeds up installation and removal of the product.

Homemade retainer

If the workpieces are small, then a device for securing them at an angle of 90 ° can be made independently from available material. You need to take a metal corner, a strip (two pieces) and two clamps. To set a right angle, you will need a square; no other tool is required.

The length of the corners can be any. The strip is welded at an angle of 45 degrees to each corner so that they form an isosceles right triangle.

In order to prevent the structure from moving, you first need to grab it in four places and only then boil it completely. The resulting device, when secured to the table, will last for more than one year.

Application of magnets

When welding at home, it is convenient to use magnetic clamps. They are electromagnetic and based on permanent magnets. Electromagnets are used more in production. For household needs and small industries, latches with permanent magnets are convenient. They are compact, can be installed anywhere, and some have a variable angle of fixation.

The simplest in design and most common are magnetic squares. It is enough to apply the square to the part to be welded with one plane, and accordingly position the second part to obtain reliable fastening at a right angle.

It remains to grab the parts in several places. After this, the product is completely welded. Without tack, magnetic angles will not withstand temperature deformations during welding.

In addition to squares, there are universal magnetic devices. They can fix the welded products in many positions.

As an example, consider the MagTab device. The device has two main planes with magnets. The angle between the planes changes, so the device can be mounted on a cylindrical, flat surface or in any corner.

There are two more planes to which the parts are attached. The planes are located at right angles and have the ability to move relative to the base. This makes it possible to install the product to be welded in the position that is required.

If you have powerful permanent magnets, especially neodymium ones, you can make such devices yourself. When using magnetic fasteners, you need to take into account that they lose their strength when exposed to high temperatures, so you need to avoid overheating them.

Pipe connection

Welding is often used when pipelines need to be connected. In this case, the question often arises: how to weld one pipe to another pipe perpendicularly.

If profile pipes of rectangular or square cross-section are used, then everything is very simple. At the junction, in the pipe to which the other will be welded, it is necessary to make a cutout for the cross-section of the product being cut into.

After this, they need to be installed in an angle clamp and clamped with a screw, or in any other device that ensures a perpendicular connection of the parts. Then tack is done in several places and then everything is boiled all around.

When welding round pipes, everything happens exactly the same. Only additionally, at the end of the welded pipe, a cutout is made with a radius that matches the radius of the main pipe. This ensures a good joint, which will allow you to get a high-quality seam.

Adapters are often used to connect plastic pipes at right angles. The part is called a 90° angle. It allows you to quickly and easily ensure the accuracy of the angle of rotation.

Source: http://ooo-asteko.ru/kak-privarit-trubu-k-trube-perpendikulyarno/