How to properly weld a pipe using electric welding

Electric welding with electrodes for beginners: how to weld correctly

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.

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.

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.

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.

After preparation, you can start working. It is necessary to weld all joints continuously, completely welding . Pipe joints with a width of up to 6 mm are welded in 2 layers, with a width of 6-12 mm in 3 layers and with a wall width of more than 19 mm in 4 layers. The peculiarity lies in the constant cleaning of pipes from slag, i.e.

After each completed layer, it is necessary to clean it of slag and only then cook a new one. Particular care must be taken when working on the first seam, it is necessary to fuse all blunts and edges.

The first layer is carefully checked for the presence of cracks; if they are present, then they must be melted or cut out and welded again.

All subsequent layers are welded while slowly turning the pipe. The last layer is welded with an even transition to the base metal.

Mistakes of novice welders

To learn how to cook with electric welding correctly, you need to consider the main mistakes that beginners make :

1. Moving the electrode too quickly, resulting in an uneven seam.
2. The seam moves too slowly, resulting in holes and burns in the metal.
3. The seam is too uneven and flat. The error here is in the angle of the electrode.
4. Lack of welding of metal. This happens because the 5 mm gap between the metal and the electrode was not maintained, i.e. the gap was too small.
5. Otherwise, when the gap is too large, the metal is not welded.

All of the above mistakes are just the most serious ones. There are many more nuances that can only be understood with experience.

When welding thin-walled metal or profiles, a careful approach to work is required . Thin parts can be welded by applying a cleaned electrode and welding directly on top of it.

Welding on non-ferrous metals is strikingly different, as it requires different electrodes. A special protective environment is also required. Now you can buy universal machines that cook almost any metal.

There are also semi-automatic devices for working with thin-walled metals. Its essence lies in fusing a special wire.

Electric welding for beginners is not an easy task. But if you have enough desire, you can master it. You just need to follow the basic rules and listen to the advice of more experienced masters. As a result, you will be able to move on to complex tasks, honing your skills.

Source: https://tokar.guru/hochu-vse-znat/svarka-elektrodami-kak-pravilno-varit-nachinayuschim.html

Welding pipes using electric welding - what is needed for the work and how to carry it out

Manual electric welding is the most famous method of pipe installation, which, despite its apparent simplicity, requires not only a careful approach to the work, but also precise adherence to the technique of performing it. Let us immediately note that before electric welding pipes, it is necessary to carefully prepare their joints for the upcoming procedure.

Preparation of joints and choice of welding method

Preparation of joints for welding is carried out by simple mechanical processing of the latter. In special cases, one or another abrasive tool is used to process the edges. After processing the joint, there should be no burrs or sharp corners left on its edges, which must be removed using a rasp or abrasive wheel.

Manual electric welding of pipe products can be carried out using the following known methods:

• arc welding using so-called covered electrodes,
• argon arc welding, which involves the use of non-consumable electrodes.

In this article we will consider the first of these methods (as a simpler one), usually used for welding carbon steels. Before starting work, first of all, you will need to decide on the modes, which involve choosing the following set of parameters:

• type of current (“direct – alternating”), the choice of which is determined by the thickness of the walls of the pipes being welded, as well as the grade of steel and the type of electrodes used,
• the magnitude of the operating current, depending on the thickness of the electrodes used. You can determine its value in amperes by multiplying the diameter of the electrode by 35,
• the optimal arc size (its length), the value of which can vary from half the thickness of the electrode to its full diameter plus one,
• the rate of “leading” the arc is selected, as a rule, based on the size of the welding seam.

Summary tables of the values ​​and interdependencies of all these parameters are given today in many sources on the Internet, so it will not be difficult for you to understand this issue in more detail.

Welding simple (fixed) joints

Vertical simple (or non-rotating) joints are welded, as a rule, in two passes. In this case, the circumference of the joint is mentally divided into two halves using a conventional vertical segment. Welding of each of these conditional semicircles should begin from the upper (ceiling) position, and then smoothly “lead” the arc through the so-called horizontal section towards the lower sector.

Each of these areas should be cooked using a short arc, the length of which corresponds to the half-diameter of the electrode. The amount of overlap of the resulting seams (or “lock”) is determined by the diameter of the pipe and can vary from 20 to 40 mm.

Quality control and work safety

The simplest and most natural way to control the quality of a weld is to visually inspect it, during which you can identify not only the presence of burns, cracks or undercuts, but also detect areas that are not fully welded.

Before inspecting the seams to be inspected, they must be thoroughly cleaned of slag formed during welding. Control of the geometric dimensions of seams is carried out according to standard procedures using probes, templates and other measuring devices.

A mandatory organizational condition for work of this class is compliance with safety requirements that prescribe a certain procedure for their implementation. Compliance with all these requirements will allow you to avoid electric shock, and will also eliminate the possibility of burns from melt particles and eye damage from welding radiation.

To protect against all these damaging factors it is necessary:

• make sure the insulation of metal parts of welding equipment is reliable,
• organize grounding of the housing of auxiliary electrical devices (power supplies),
• use only well-dried protective clothing,
• When welding, use a protective shield that completely covers the operator’s face.

Expert advice

Before welding pipes using electric welding, experts advise preparing special equipment that increases the convenience and quality of the work performed. For products of small diameter (up to 10 cm) with walls thickness from 2 to 10 mm, such equipment can be used as follows:

• The pipes are secured in special devices (such as a hoop) and then clamped at one or more joint points.
• With a single tack, the joints are scalded entirely, starting from the side opposite to it.
• When the wall thickness is less than 3 mm, the tack is done using a 2.5 mm electrode.

For joints of pipe products with walls thicker than 4 mm, welding should be carried out in two beads, and the second seam should be applied in the opposite direction (relative to the first).

How to weld pipes using electric welding
Tips for welding pipes using electric welding yourself. Arc welding rules.

Source: https://trubyisantehnika.ru/%D0%BA%D0%B0%D0%BA-%D0%B2%D0%B0%D1%80%D0%B8%D1%82%D1%8C-%D1 %82%D1%80%D1%83%D0%B1%D1%83-%D1%8D%D0%BB%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D1% 81%D0%B2%D0%B0%D1%80%D0%BA%D0%BE%D0%B9.html

How to weld a pipe using electric welding

Welding a pipe using electric welding

Metal pipes are one of the most common metal structures on the planet. Often in everyday life and at industrial or production facilities, electric welding is used to join pipes and build a pipeline.

Welding these metal structures is a very responsible procedure, especially if liquid flows through the pipes under different pressures and different temperatures. The requirements for the weld are higher than in the case of welding any other metal parts. This article will discuss the main aspects of how to weld a pipe using electric welding.

Theoretical information

The main difficulty when carrying out any welding work is creating a high-quality seam. In the case of pipes, its quality largely depends on several criteria:

• Condition of the surface of the pipe sections being welded;
• Accuracy of alignment of ends;
• The electrode used is what is most important.

To build a pipeline, high-quality electrodes with sizes from 2 to 5 mm are usually used. The main requirements for electrodes are that they must be thick and have a powder coating of 20 to 30% of their total weight.

As is known, powder coating serves to form a film (slag) at the point of contact between the electrode and the surface to be welded. This helps protect the weld pool from ambient oxygen and nitrogen entering it, and therefore prevents the formation of oxides and cracks. An oxidized seam may crack in the near future, which is unacceptable when welding any metal parts at all.

Electrodes of brands E-42, E-42A or similar ones are excellent for welding pipes.

Another important point is the selection of the correct diameter of the electrodes. The diameter should be selected based on the wall thickness of the pipes themselves. For walls up to 5 mm thick, electrodes with a diameter of 3 mm are suitable, and if the thickness is more than 5 mm, then electrodes with a diameter of 4-5 mm are used.

You also need to pay attention to the current selected for welding. If rotary pipe joints are welded, a current of 100 to 250 amperes is selected; for straight joints, a current of 80 to 120 A is sufficient.

How to weld a pipe using electric welding?

Before starting work, the surfaces to be welded must be cleaned of any contamination and then polished to a shine. The following rules are also required:

• If there are jagged or grooves on the pipes, these defects must be eliminated;
• Welding should be continuous and end only after the entire joint is completely welded;
• The use of backing rings is not permitted;
• If the wall thickness does not exceed 6 mm, it is necessary to weld pipes in two layers, 6-12 mm - in three layers, and from 19 mm - in four or more;
• The first layer is the most important, so it must be of the highest quality. Before welding subsequent layers, the surface is cleared of slag.
• The electrode must be positioned perpendicular to the surface to be welded. But sometimes exceptions are made.

The above rules are a proven method of how to weld a pipe using electric welding. However, many professional welders weld the joints of these metal structures a little differently. Below we will give one of these techniques, which will tell you how to weld a pipe in a vertical position, which is most often required in domestic conditions.

Welding starts from the bottom. The electrode is positioned, as usual, perpendicularly. Welding is carried out in any direction. As soon as the lower part is welded and the seam has reached the side surface, the angle of the electrode is slightly changed so that it looks up. Thus, the weld pool will not flow down. At the top of the pipe it is again installed perpendicularly. After this, welding is stopped and welding begins again from bottom to top, but on the other side of the pipe.

Source: http://stroysvarka.ru/kak-zavarivat-trubu-elektrosvarkoj/

Welding with an inverter for beginners: how to learn to weld from scratch and the basics of arc welding

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

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

Basics of electric welding

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

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

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

To understand how to cook using inverter welding, you need to understand the basics of its operation.

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

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

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

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

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

Welding methods

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

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

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

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

Methods and types of welding.

Other types of welding are listed below:

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

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

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

Step-by-step instructions for welding with an inverter

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

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

Electrode position during welding.

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

Proper preparation of the workplace consists of:

• ensuring the necessary free space on the table, you should remove all unnecessary objects that could get splashed;
• creating high-quality lighting;
• Welding work must be performed while standing on a wooden floor that protects against electric shock.

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

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

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

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

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

Electrical circuit of the inverter.

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

The welding process begins with ignition of the arc.

There are two ways to perform this action:

• scratching on metal;
• tapping on metal.

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

After igniting the arc from contact with the metal, the arc is ignited, the welder removes the electrode from the surface of the part a short distance corresponding to the length of the arc and begins welding.

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

Forward and reverse polarity

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

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

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

Direct and reverse polarity.

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

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

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

Effect of electrode feed speed

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

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

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

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

Effect of current

Welding current selection table.

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

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

Features of welding thin metal

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

Here are some useful tips that can help improve your skills:

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

Common mistakes made by newbies

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

The following main errors can be identified:

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

Let's sum it up

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

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

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

Source: https://tutsvarka.ru/vidy/svarka-invertorom-dlya-nachinayushhih

How to properly weld a pipe using electric welding

There is an opinion that welding pipes is a fairly simple technological operation that even a beginner can handle.

Indeed, it would seem that there is nothing complicated here. The parts are quite large, the connecting surfaces are well adjusted to each other and processed, the material is of high quality. At first glance, there is everything necessary to form an aesthetic and durable seam!

In practice, however, it turns out completely differently. This process is quite difficult, especially when it comes to the formation of a full-fledged pipeline operating under pressure. The best specialists are attracted to work with its segments.

Why is this happening? How to perform high-quality welding without significant experience? What tips and tricks should you follow?

Core Technology

The most common and popular technique is electric arc welding.

Yes, it has alternatives in the form of gas welding, but its undeniable advantages lie in simplicity, a minimal set of equipment and a result that meets the most stringent standards.

Even when designing main pipelines, this method is used. To achieve high quality, you must treat your work with full responsibility.

Selecting Electrodes

The connection of steel pipeline segments must be carried out using high-quality consumables, otherwise it is unlikely that a good result will be achieved.

For example, when it comes to choosing electrodes, the following models are considered the best:

• ANO-21, ANO-24 and MR-3 . They operate on alternating currents. Work is allowed even with wet coating. The cost of the products is low, which explains their demand in everyday life; they are ideal for connecting structural elements of gates, greenhouses and other light-weight structures that do not experience high loads. Work with pipelines in which the medium is transported under significant pressure is not permitted.
• SSSI . The quality of the cores deserves flattering reviews even from professional welders, but they have a disadvantage - work cannot be carried out at high speed. It is necessary to constantly monitor the stability of the arc; the weld is deposited gradually, so the worker must have some experience in interacting with classic ANO and MR electrodes.
• LB-52U electrodes are excellent for metal pipes . This is a Japanese development. It is the one that is preferred when implementing large projects. They form an even and stable arc, the resulting seam combines strength and aesthetics. The downside is the rather high cost, but they are suitable for both specialists and beginners.

Watch a video on the topic of which electrodes to use for welding pipes:

Basic methods

The connection can be made in one of the following ways:

1. Butt joint, when the pipes to be connected are placed opposite each other. The most common option, characterized by relative ease of implementation. However, it is also characterized by certain difficulties. The first point is that it is better to work from below. The second point is that it is necessary to thoroughly weld the metal so that the depth of penetration corresponds to the thickness of the wall.
2. Overlapping. This method is focused on connecting elements that initially differ in diameter, or segments, one of which is flared, that is, its diameter is intentionally increased by mechanical action.
3. The T-joint is made at a 90-degree angle.
4. A corner connection assumes that the angle between the connected segments is less than 90 degrees.

Useful tips

Before electric welding pipes, it is worth remembering a number of tips, following which will simplify the process and also improve the quality of the final result:

• If the connection is made using the butt or tee method, then electrodes whose diameter varies from 2 to 3 millimeters perform best.
• The recommended amperage is from 80 to 100 amperes, with the exception of overlap welding, when it is recommended to increase it to 120 amperes.
• When filling a welding seam, you need to ensure that the rise of the metal above the plane of the element reaches 2-3 millimeters.
• If the cross-section of the pipe is not the usual ovals or circles, but profiles, that is, rectangles and squares, then a point method of connecting it is used.

Its essence is that initially you need to weld a small area on one of the sides. Next - a similar section on the opposite side, then - on the remaining two planes. Only after this the pipe is finally welded.

This approach makes it possible to eliminate the possibility of warping of the product when the temperature rises; its geometry remains stable.

Preparatory operations

The final quality of the joint depends not only on the professionalism of the welder and the use of the “correct” electrodes, but also on how well the preliminary preparation is done.

It consists of the following operations:

• Checking the compliance of the geometry of the connected elements with the selected technology. It must be remembered that the wall thickness must be identical, otherwise it will not be possible to fully weld a thick-walled pipe, and in the case of working with a thin-walled product, on the contrary, the risk of burn-through increases.
• The presence of defects on the welded products, be it cracks, creases or deformations, is not allowed. During the process of thermal expansion, they can turn into areas of complete destruction of the structure.
• Geometric deviations of the cut are not allowed. Its angle must be 90 degrees, otherwise the welding seam will not be strong enough and problems will arise with its formation, which will pose a threat of destruction of the entire structure.
• The edges of the connected pipes must be cleaned until a shiny metal surface appears, for which coarse sandpaper or a special brush is used. The minimum length of the area to be cleaned is a centimeter from the edge.
• Grease and other contaminants, traces of paint and corrosion are removed. The most effective removal agent is a chemical solvent.

This video shows how to prepare the edges of a pipe for clearance using a grinder:

Process Features

Pipe welding technology requires following the following rules:

• The seam must be continuous, that is, end at the point of its beginning. Tearing of the electrode from the surface is not allowed. It is impossible to follow the rule if the pipe diameter is too large. In such a situation, multilayer welding is used. The number of layers must be correlated with the thickness of the walls.

2 layers correspond to a thickness of less than 6 millimeters, 3 – from 6 to 12, 4 – more than 12. Before applying subsequent layers, you need to make sure that the first one has cooled completely.

• Before welding two pipes, they need to be fixed. The tack will simplify the work, eliminate transverse and longitudinal movements, and allow you to form an even and strong seam without unnecessary effort.
• When the pipe wall thickness is more than 4 millimeters, it is possible to form a root seam, the main feature of which is to fill the area between adjacent edges to the full depth. An alternative to a root seam is a roller analogue, which is identified by a 3 mm bead on top of the seam.
• Checking the quality of the seam. It is tapped with a hammer, which allows you to remove slag inclusions. After this, a visual inspection is carried out; cracks, areas with insufficient penetration, chips, gouges, and burns are not allowed.

If a liquid or other medium under pressure will be transported through pipes, a test run is carried out to determine the tightness.

Source: https://nevkucnogo.net/kak-pravilno-zavarit-trubu-jelektrosvarkoj.html

How to weld a thread to a pipe using electric welding?

In a situation where it is necessary to connect metal parts, they most often resort to the method of creating a weld, since it can provide fairly high reliability. This method has become widespread not only in industry, but also in ordinary everyday life.

The vast majority of home craftsmen periodically use welding. Those of them who have welding skills are lucky. If they are not there, then in this case there is nothing left but to contact specialists.

But anyone can learn to cook if they want. And the first thing you should pay attention to at the very beginning is to familiarize yourself with the basics of electric welding for beginners .

We are talking about lessons that tell you about the features of creating various seams. More complex work should be started only after the owner has gained sufficient experience.

Next, we will dwell in more detail on the nuances of welding work and certain tricks of this process.

Where to start the preparatory stage?

The first thing those who want to learn how to cook need to do is purchase the necessary equipment . The complete kit that will be required to complete such work will include:

• welding machine;
• set of electrodes;
• hammer for beating off slag;
• brush.

When choosing an electrode, you need to pay attention to its diameter, which will be determined by the thickness of the metal sheet being welded . You should also take care of protection. For welding we need:

• welding mask with a special light filter;
• thick clothes with long sleeves;
• gloves, preferably made of suede.

The tools required for welding work must include a welding rectifier, transformer or inverter. It is with the help of these devices that the problem of converting alternating current into direct current will be solved, which will allow welding.

Welding process technology

When starting electric welding, you should remember that this work is carried out at high temperatures. Such work is ensured by an electric arc, which must be maintained between the electrode and the workpiece being welded.

It is during its contact with the workpiece that the base metal and welding electrode melt. At this moment, a phenomenon occurs, which among specialists is called a weld pool. In it, the base and electrode metal are mixed into a homogeneous mass.

The bath can have different sizes, which is determined by the welding mode used, spatial position, speed of arc movement , shape and size of the edge, etc. Usually it reaches a width of about 8–15 mm, a length of 10–30 mm, and a depth of about 6 mm.

Each electrode has a special coating called coating. At the moment of its melting, a special gas zone appears in the arc area and above the bath. Thanks to it, air leaves the welding zone and the interaction of molten metal with oxygen is eliminated. It also contains pairs of base and electrode metal.

Already on the seam itself an alloy appears that does not allow the melt to come into contact with air, which would deteriorate the quality of the welding. As the electric arc is removed, the metals crystallize, resulting in a seam , thanks to which the welded parts are firmly connected. At the seam itself there is a protective layer of slag, which must be removed after welding.

Basics of electric arc welding

To get the best possible results when creating a weld, novice welders first need to familiarize themselves with the lessons, which pay attention to the correct execution of this work in the first stages.

It is also advisable to get practice in performing welding work under the guidance of an experienced specialist, who will not only point out mistakes, but also tell you how to avoid them in the future.

Before you start welding parts, you need to make sure that it is securely fixed enough.

It is equally important to take care of compliance with fire safety rules: for this it would be useful to place a bucket of water nearby. This also explains the ban on welding on a wooden base. You should also pay attention to small remnants of used electrodes , which should not be left at the workplace after completion of work. Without this, it is impossible to learn how to weld metal correctly.

It is imperative to make sure that the “ground clamp” is securely fixed. Make sure that the cable is insulated and accurately inserted into the special holder. Before working with a welding inverter, you should select a calculated current power indicator, which should be determined based on the diameter of the electrode.

After this, you can strike the arc . This is done as follows: you need to place the electrode at an angle of about 60 degrees relative to the product. Next, you need to slowly move it across the surface. At this moment sparks appear, now you need to touch the metal with the electrode and then lift it, but not higher than 5 mm.

If all recommendations are strictly followed, the arc should light. Until the welding is completed, you need to keep the electrode at a distance of 5 mm. It should be borne in mind that during metal welding, the electrode rod will gradually begin to burn out.

Therefore, at regular intervals you need to reduce the distance between it and the metal. Approach the electrode to the workpiece slowly. A situation may arise where it sticks. In this case, you need to slightly turn it to the side . If all attempts fail to ignite the arc, then you can try increasing the current.

When the arc ignites and its flame becomes stable, you can begin fusing the bead. The electrode with the other one lit must be slowly and smoothly moved horizontally, making gentle oscillatory movements.

This will cause the liquid metal to begin to move on its own directly to the center of the arc.

If you follow all the recommendations, you can make a reliable seam formed in the form of small waves that were created using deposited metal.

A situation may arise that during welding of products the electrode will be completely used up, but at the same time it will not be enough to create the entire seam. In this case, you need to take a break from work.

After turning off the machine, you need to insert a new electrode , remove slag from the surface of the weld, and then continue welding. From the depression created at the end of the seam, often called a crater, you need to make an indent of about 12 mm and light the arc.

The electrode should be brought closer so that upon contact an alloy is formed from the metal of the old and newly installed electrode. Next, welding is performed as usual.

Features of welding a pipeline with an inverter

The electric arc welding method is suitable for creating a vertical seam, provided that it is located at the end of the pipe. If a horizontal seam is created, the latter should be on its circumference. If you have to make ceiling and bottom seams, then they should be at the top and bottom. Among all those mentioned, it is the last one that creates fewer problems in implementation.

If you have to deal with steel pipes, then the butt welding method is most often used, which involves welding each edge along the height of the walls.

To minimize sagging inside the pipe, the electrode should be positioned at an angle of no more than 45 degrees relative to the horizontal. Such a seam should reach a height of 2–3 mm and a width of 6–8 mm.

If the products are overlapped, then the seam will have a height of 3 mm and a width of 6–8 mm.

Preparation

Before you begin electric welding of metal products, you need to complete the following preparatory measures:

• It is necessary to remove the top layer from the welded aliment.
• If there are any irregularities at the ends of the pipe, they need to be cut off or straightened.
• Next we begin to process the edges. Here it is necessary to smooth out at least 10 millimeters of the surface adjacent to the edges of the pipe outside and inside until a metallic sheen appears.

Main stages

Next, you can begin directly welding the pipe. Each joint must be processed continuously until they are completely welded. Rotary and non-rotary joints of pipes with walls no larger than 6 mm should be created in at least two layers.

If the walls have a width of 6–12 mm , then three layers should be created, more than 19 mm - 4 layers.

When welding pipes, it is necessary to take into account one important nuance: it is necessary to remove slag from the next seam created at the joint, only after this can you proceed to creating a new one.

Particular attention should be paid to creating the first seam, since a lot depends on it. It must be performed in such a way that it melts every edge and dull areas. It is very important to examine it very carefully, as there may be cracks on it.

If they are found, they must be melted down or cut down, after which the area is welded again . When creating the remaining layers, you need to slowly turn the pipe.

The finishing layer must be created so that it provides a smooth transition to the base metal and at the same time has a flat surface. You can achieve the highest quality of welding pipes using welding if the next layer is performed in the opposite direction with respect to the previous one, while their closing points should be scattered from each other.

Conclusion

Welding work is quite complex, so novice welders will have to spend a lot of time and effort to create high-quality and durable welded joints. But first, they should get an idea of ​​the main points from the lessons , without which it is impossible to weld metal efficiently and correctly.

It is important not only to prepare all the necessary tools and materials, but also to study the technology of the welding process with special care. This is very important because any mistake can subsequently affect the quality of the weld, and if attention is not paid to this at the initial stage, then in the future all efforts will be in vain, as a result everything will have to be redone.

• Vitaly Danilovich Orlov

Source: https://varimtutru.com/kak-privarit-rezbu-k-trube-elektrosvarkoy/