How to properly weld a pipe from below

Pressure welding of pipes and tapping into water pipes

Pressure welding of pipes and tapping into water pipes

Welding pipes under pressure is very difficult even for experienced welders, not to mention beginners. Constantly flowing water from the pipe prevents the welding arc from burning normally, making it very difficult to obtain the required melting temperature of the metal.

In addition, when welding water pipes under pressure, a large amount of steam is generated, which interferes with the quality of welding work. And, nevertheless, in this article on the site about manual arc welding mmasvarka.ru, advice will be given on how to weld pipes under pressure.

What electrodes should be used to weld water pipes?

The best electrodes for welding water pipes under pressure have long been considered:

UONI 13/15 electrodes are universal high-quality electrodes for MMA welding, which make it possible to repair leaking pipes. The weld seam formed by UONI 13/15 electrodes has a high combination of ductility, strength and toughness, which in turn makes it possible to weld fistulas and other damage to water pipes.

MGM-50K electrodes are a relatively new type of electrodes that are optimized for welding pipelines under pressure. The peculiarity of welding with MGM-50K electrodes is that a gas bubble forms around the arc, which can push away steam and even liquid that is not under too much pressure. All this simplifies welding work related to the repair of water pipes, and also makes it possible to carry out repair work on time.

Welding pipes under pressure

By adhering to the tips below, you can significantly facilitate the work associated with the repair of water pipes under pressure:

1. When welding a pipe, when water comes out of it, the current on the welding machine should be increased. In this case, the electrode will not stick to the pipe all the time due to the fact that the metal cools too quickly.
2. Before welding pipes under pressure, the electrodes should be calcined. In this case, you can achieve a better and more stable arc, which, in turn, will quickly evaporate leaking water from the fistula.
3. The choice of direct or alternating current for welding water pipes depends not only on the pressure of the water layer, but also on the thickness of the metal that needs to be welded.

For example, welding with alternating current makes it possible to form a more powerful arc. Therefore, even pipes under high pressure can be welded “in alternation”.

At the same time, the quality of the weld leaves much to be desired. In turn, DC welding allows deep penetration of the metal and greater strength of the welding joint.

How to weld a fistula in a pipe with water under pressure

Let's look at a specific example of how you can weld a fistula (small hole) in a pipe under pressure:

1. Choose a position from which you can easily see the damage to the pipe;
2. Try to keep the electrode perpendicular to the defect in order to reduce the amount of water entering the electrode;
3. Work from top to bottom until the fistula is sealed.

To weld a fistula in a water pipe under pressure, you first need to weld some metal to the top of the damage. Then, hitting it several times with a hammer, try to compact the defect and thereby stop the abundant formation of steam.

After this, you need to continue eliminating the fistula, in this way, until the hole in the pipe is completely blocked. The cycle, again and again, continues from top to bottom, not without the participation of a hammer. After water stops flowing from the pipe, the defective area should be strengthened, while reducing the value of the welding current.

Plumbing under pressure

And although today there are special saddles for inserting into water supply under pressure, many still use welding for these purposes. How to cut into a water pipe under pressure?

First of all, you need to prepare a metal pipe of the required diameter, at one end of which a thread would be cut. A ball valve must be screwed onto the thread, with a preliminary seal (plumbing flax or fum tape).

Having chosen the insertion location and cleaned the pipe from dirt and rust, you can begin welding work:

1. Attach the pipe with the tap to the pipe for tapping, then weld it in a circle. This work is not easy, because you need to avoid burning through the metal of the pipeline while maintaining its integrity;
2. Using an open tap on the pipe, drill a hole in the pipeline using a drill and a long metal drill for this purpose;
3. After water comes out of the pipe, quickly turn off the tap.

Thus, it is possible not only to weld a fistula in a water pipe under pressure, but also to cut into an existing pipeline.

Source: https://mmasvarka.ru/svarka-trub-pod-davleniem.html

Do-it-yourself pipe welding using electric welding

The most common method of installing utility networks is electric welding of pipes.
Do-it-yourself electric welding of pipes is a fairly simple process. You just need to carefully follow the steps and technique of doing this work.

Steel parts

1.Incoming control

Manual electric arc welding of pipes begins with checking that the pipe meets regulatory requirements.

What to check:

• Availability of a certificate of conformity.
• Labeling.
• Carbon equivalent. This value indicates the weldability of the steel. Depending on the carbon content, the pipe welding technology is selected.
• Part length.
• Part diameter and wall thickness.
• Wall thickness.
• Ovality of the ends of the part.
• Curvature of the part.
• The presence of damage and defects on the metal surface.

2.Preparing joints for welding

Preparation of joints is carried out by mechanical processing or thermal cutting. If thermal cutting was used, then the resulting edge must be processed with an abrasive tool or cutter.

If you plan to weld a pipe from low-alloy or carbon steel without using a backing ring, chamfer only mechanically. The edges on pipes made of alloy and high-alloy steels (including stainless steel) are cut in the same way.

The prepared edge should not have sharp corners, burrs, tears or sharp transitions. All these “excesses” are carefully cleaned with a file or an abrasive wheel.

To control the quality of edge processing, welders use inspection templates:

• corners;
• exceeding edges;
• dulling of edges;
• gap in the lap joint;
• gap in the T-joint;
• gap in the butt joint.

Root bead welding

3. Selection of pipe welding technology

Electric pipe welding is mainly performed in two ways:

The first method is used for carbon steels, the second - for alloy steels (including stainless steels).

1.Modes:

• The type and polarity of the current depends on the thickness of the pipe wall, the grade of steel and the grade of the coated electrode.
• The welding current is determined by the thickness of the electrode. To calculate it, you need to multiply the diameter of the electrode by (30-40). The resulting number will be equal to the welding current in amperes.
• The arc voltage is determined by its arc. The optimal arc length ranges from half the electrode diameter to the full electrode diameter plus 1.
• The welder selects the welding speed depending on the geometric dimensions of the seam.

Nowadays on the Internet you can find tables of dependencies of all the listed quantities.

In addition, there you can find a lot of educational materials that cover electric pipe welding in detail: videos, instructions, recommendations.

2.Assembling joints of small-diameter pipes (up to 100 mm) with a wall thickness of 2 to 10 mm from low-carbon steels:

• The joints are assembled in fixtures and clamped at one or two points. If there are two gripping points, then they are located symmetrically.
• Joints fastened with one tack are scalded immediately, starting from the side opposite the tack;
• If the wall thickness is less than 3 mm, tacking is performed with an electrode with a diameter of no more than 2.5 mm;
• The joints of a product with a wall thickness of more than 4 mm are welded in at least two layers - the root seam and the facing bead.
• When welding parts with a diameter from 30 to 83 mm, the vertical joint is welded in sections along ¾ of the perimeter;
• Each subsequent horizontal joint bead is laid in the opposite direction;
• The “locking” sections of subsequent rollers are shifted relative to the previous seams.

3. Rotary joints:

• When welding joints in rotators, the rotation speed of the product must be equal to the welding speed.
• The position of the weld pool, most convenient for forming a seam, is not at the highest point of the joint, but at a point 30-35 degrees from the vertical in the direction opposite to rotation.
• If the use of rotators is impractical or they are not available, the welded joints must be rotated at angles of 60-110 degrees. Thanks to this, the seam is formed in the most convenient, lower position.
• pipes rotated 180 degrees are welded in three steps:

1. first, in two steps, weld the two upper quarters of the pipe diameter in the direction towards each other in one or two layers;
2. then turn the pipe 180 degrees and weld the remaining part of the joint to its full thickness;
3. then the pipe is turned 180 degrees again and the remaining cut is boiled.

4. Welding of fixed joints:

• Vertical non-rotating joints are welded in two steps. The perimeter of the joint is conventionally divided by a vertical center line into two sections. Each of them has three positions: ceiling, horizontal and bottom. The ceiling is the area that occupies approximately 20 degrees from the lowest point of the part.

The lower position is a section that also occupies approximately 20 degrees from the top point of the part. Between these positions is the horizontal position.

Welding begins from the ceiling position and ends at the bottom (i.e., it is carried out from the lowest point of the part to the highest point).

Each section is welded with a short arc equal to half the diameter of the electrode. The overlap of the seams (lock) depends on the diameter of the part and can range from 20 to 40 mm. You need to start welding with a “backward angle” and end with a “forward angle”.

• Horizontal non-rotating joints are welded at an angle backwards. The inclination of the electrode relative to the vertical axis should be 80-90 degrees. Cook with a medium arc.

Modes:

• When welding in one pass, the welding current depends on the wall thickness of the part, and when welding in multiple passes, on the height of the bead. For each mm of electrode diameter, 30-35 A is assigned.
• The arc voltage is kept to a minimum, which corresponds to short arc welding.
• The welding speed is adjusted to ensure that the edges are fused and the dimensions of the seam are formed.
• Argon consumption depends on the steel grade, welding current mode and ranges from 8 to 14 l/min.
• It is necessary to weld a continuous seam immediately after installing the tacks, which should be remelted when performing the first layer.
• The argon supply stops only 5-8 seconds after the arc breaks.

6. Weld quality control

• The most common method of welding control is external inspection. During the inspection, the presence of cracks, burns, undercuts, lack of fusion, etc. is revealed.
• Before starting the inspection, the welds must be cleaned of slag. All seams without exception are inspected.
• To check the geometric parameters of seams, templates, probes, and standard measuring tools are used.
• The tightness of the seams is checked with water (hydraulic test) or gas (pneumatic test).

7.Safety

When performing welding, injuries of this kind, electric shock, burns from molten metal, and eye burns from radiation may occur. To prevent this from happening, you must:

• reliably isolate all live parts;
• ground the housings of power supplies and auxiliary equipment. The cross-section of the grounding wires must be equal to or more than 25 square meters. mm.
• overalls and gloves must be dry;
• in tight spaces, rubber mats and galoshes should be used;
• Do not start work without a protective shield, the size of which completely covers the welder’s head and face.

8. Welding pipes using electric welding: price

The cost of welding pipes depends on the diameter and material of the part. So, for example, one cm of pipe joint DN15 costs 25 rubles, and DN50 – 22 rubles.

( 1 rating, average 5 out of 5 )

Source: https://elsvarkin.ru/texnologiya/cvarka-trub-elektrosvarkoj/

What electrodes are best for welding heating pipes?

The selection of electrodes for welding pipes is a fundamental process on which the quality of the seam and its reliability will ultimately depend. It is necessary to take into account absolutely all the nuances, even the most insignificant ones, but, unfortunately, many welders, including professionals, do not always pay due attention to this.

If we are talking about laying profile or standard pipes, sooner or later you will have to use a welding machine. When choosing an electrode, you should know about the first and most important difference between them: they can be melting or non-melting.

Features of consumable electrodes

To produce this type of electrode, welding wire is used; it has a protective coating, which is necessary to stabilize the operation and the required magnetic characteristics. And the non-melting one is made from graphite, tungsten and electric coal.

The coating for the consumable electrode is also necessary to be able to obtain a high-quality and reliable seam; it is applied by immersion in molten metal and pressing.

What are the advantages of consumable electrodes:

1. They allow welding from any position.
2. Increased productivity.
3. Minimal influence of oxidation on the joining process.
4. Safe for the welder while working.

Flaws:

• high radiation of the welding arc;
• spattering during welding;
• Current limits have been set.

These are the main parameters that should be taken into account before selecting the required electrodes.

How to choose the right electrode

The rods may differ in their thickness and amount of coating. For welding galvanized pipes or any other, electrodes with a diameter of 2-5 mm are used. And the coating itself will amount to from 5% to 20% of the total mass of the product.

Most often, specialists use thicker rods. This happens because they are able to provide the necessary atmosphere to the welding process, which prevents air from entering the joint area.

But it is also worth considering that they are distinguished by a large amount of waste released. And they, in turn, can affect the reliability of the docking.

Therefore, it is necessary to learn to find the golden mean for optimal work with pipeline welding.

How to choose an electrode, taking into account the thickness of the pipe?

1. If the thickness of, for example, stainless pipes is 5 mm, then the electrode should have a diameter of no more than 3 mm.
2. When the pipe is larger than 5mm, 4mm rods will be required.
3. Also, a diameter of 4 mm is used for multi-layer formation of a welded joint.

It is also worth taking into account the maximum current that the rod can pass through, and the consumption of electrodes when welding pipes, which will help reduce financial investments.

Pipeline welding process

Once the choice is made, you can proceed to the welding process. First, you should understand how to move the arc along the connection; a few simple tips from experts will help with this:

• the arc is drawn transversely, using oscillatory movements to obtain the required seam thickness;
• if you move the arc longitudinally, this will allow you to make a thin seam with a height that completely depends on the speed of movement of the selected rod along the surface to be joined;
• To maintain the stability of the electric arc, it must be carried out gradually throughout the welding process.

Note!

Safety regulations

Safety is a component of the welding process that should be approached with great responsibility. After all, if you ignore the rules, you can get serious injuries, such as burns from molten metal, eye burns from an arc flash, or become a victim of electric shock. You can avoid such situations by following simple recommendations, namely:

• the welder should not wear wet clothes while working;
• It is imperative to use a protective face mask;
• all wires through which current flows must be insulated by any available method;
• before starting welding, you must not forget about grounding the unit and additional devices, if any;
• in small rooms it is necessary to use rubber shoes or lay a rubber mat, it will act as an insulator.

Conclusion

To make the choice of electrode more prepared, it is worth taking into account the consumption rate of the rods and taking into account the connection of a certain type of pipe to the material from which the rods are made. And for an even better understanding of the selection procedure, it is best to seek advice from experienced specialists who have extensive experience in carrying out this type of work.

Sergey Odintsov

Source: https://rem-serv.com/kakimi-elektrodami-luchshe-varit-truby-otopleniya/

How to properly weld pipes using electric welding: how to weld round and other heating pipes, tips for beginners

It is quite possible to insert into a heating pipe without using welding, but you will not be able to do it yourself without the use of special equipment. Therefore, to connect to the main heating system, you will also need to use welding. In order to qualitatively weld metal elements of various kinds together, it is necessary to understand what exactly welding is.

The principle of this technology is as follows: a metal workpiece, under the influence of high current and a certain voltage, begins to melt and joins with a similar edge of another workpiece. Products begin to penetrate each other, their particles intersect with each other at the molecular level.

Largely due to this, electric welding of metal heating pipes is considered to be one of the most reliable technologies, which allows for a very high level of joint strength.

Types of welds and joints

Depending on the relative position of the pipes, they are connected:

• end-to-end, when the ends are adjacent to each other;
• in a T-bar, if the pipes are arranged in the shape of the letter T;
• at an angle when it is necessary to change direction by 45 or 90˚;
• overlap by flaring the end of one pipe and putting it on the other.

Depending on the possibility of access to the joint, the connection is made:

1. With a horizontal seam, if a vertical section of the pipeline is being installed.
2. Vertical when the pipeline is in a horizontal position.
3. Ceiling when the joint is welded from below. Such a seam has to be applied during repair of the heating system when replacing the damaged area.
4. Pipes are welded bottom when installing new systems, when it is possible to rotate them so that the electrode is on top of the joint.

What is necessary?

Successful welding requires two things: equipment and skills. Moreover, the second point is no less important than the first. The only exception is, perhaps, welding using electrical fittings, since the simplicity of the technology allows even a non-professional to make a high-quality connection.

In all other cases, the participation of a specialist is desirable. We must not forget that a violation of the tightness of a weld in a heating system can lead to very unpleasant consequences (damage to property, including someone else’s, burns, etc.).

Tools

The set of tools and equipment required for welding work is determined depending on the type of pipes used to construct the heating system, as well as the selected welding method.

First of all, this is a manual welding machine.

Insulating a balcony requires knowledge, and you can fill it in our article on how to insulate a balcony with polystyrene foam. A detailed diagram of connecting aluminum radiators is here.

Source: https://instanko.ru/osnastka/otoplenie-svarka.html

How to weld a pipe with water under pressure

The most fundamental work during the construction of a house is the installation of communications. If we are talking about heating and water supply, then for reliability it is better to do all the work yourself - carefully and without haste. Mastering the process and knowing how to weld pipes using electric welding will allow you to avoid serious financial costs and possible costs if the work was done poorly by an invited worker.

Equipment and materials

To perform manual electric arc welding yourself, you must have:

• Welding machine. The kit should contain two wires with different tips.
• Means of protection.

1. mask;
2. mittens or gloves;
3. protective clothing (long-sleeved jacket, trousers);
4. a piece of tarpaulin to cover nearby items from damage.

• Electrodes as consumables (grade according to pipe diameter and metal quality).
• A device or hammer that helps remove slag and scale from a finished seam.
• Various types of fasteners (vises, clamps, etc.).

Welding machine

Without stopping at specific brands and models, when choosing a welder, you need to pay attention to the main characteristics and parameters. What does it mean?

To perform the specified work, transformer and inverter type devices are offered. The difference is in price, dimensions, weight.

A distinctive and positive feature of inverter equipment is the nuance that when the voltage is not constant, below 220 V or during fluctuations, it does not “sag” in power. In addition, you should pay attention to the following parameters:

• Welding current. The higher the maximum current, the larger the diameter of the electrode that can be used, and this affects the size and depth of the seam.
• Duty cycle. In order for an inverter model to function for a long time and efficiently, it needs a short break (downtime) after a certain period of work. The ratio of these intervals constitutes the work cycle.

The percentages in the passports for the device can be of two standards: 5 minutes and 10 minutes.

How to decipher this?

Example 1. In a 10-minute cycle, 50% - you need to understand that we are talking about 5 minutes of work and 5 minutes of downtime.

Example 2. In a 5-minute cycle, 60% means 3 minutes of work and 5 minutes of rest.

The cycle may be different at different currents, this must also be taken into account, that is, the lower the current, the longer you can work and the less rest.

After a little practice, you will be able to independently adjust the cycle based on the technical characteristics of the purchased device.

• Another aspect that will indirectly indicate the reliability of the equipment. If the warranty period is more than a year, say 3, then naturally the device will last longer than one that is ready to be serviced only for 6 months.

Welding, step by step steps

The thermal process that occurs during electric welding connects the parts with a strong seam, which will have better mechanical properties in contrast to gas welding.

So, how to learn to cook? When we are talking about a pipe in an accessible place and with the possibility of rotation, then two sections of the pipeline are connected end-to-end by one or three electric welding points. Then:

1. continuously (if you can rotate);
2. with a tear, starting from the bottom, if the position of the pipe is inconvenient and it is impossible to rotate it, a seam is made.

Welding is performed in two passes. First, the “root” is filled - the first seam, which covers the same pipe joint (2-3 mm), then excess deposits and scale are cleaned off, and a second seam is made, which is also then cleaned.

The general instructions for the entire process look like this.

• Before starting work, take a comfortable, stable position. The space should have good lighting.
• Strike to ignite the arc; if it does not ignite, increase the current slightly.
• Move the electrode to the beginning of the seam and begin the welding pool, maintaining a constant arc gap.
• When the current is set high enough, the straightened metal will follow the heat.

However, this must be done carefully, carefully, because when this parameter is increased, the “bath” penetrates deeper and spreads, which is good. But if you overdo the current, the metal will melt so much that it will begin to bubble, and you will no longer be able to control it and make a seam.

• When welding, make sure that the edges are filled and there are no undercuts. If the current is low, the “bathtub” will be equal to the outline of the electrode; if the current is higher, then movements in a circle or from side to side will help form a welding seam.

It is necessary to monitor the quality of welding directly during the work process, paying attention to the edges of the “bathtub” and how evenly the filling is proceeding.

• Place a point, leaving some metal.
• Extinguish the arc along the seam.

You can learn how to make seams correctly and efficiently if you have the desire, but you can master all the stages easier and faster if you have ever observed the electric welding process from the outside or been a participant as an assistant.

Water supply

Before proceeding directly to electric welding, you must prepare a diagram of the future water supply, with the location of all communications. Such a layout will allow you to make the wiring optimal and be well prepared for a high-quality connection of pipes using a welding machine.

What must be observed.

• The hot water riser goes to the right, the cold water riser goes to the left (if vertical). In a horizontal position, the pipes run parallel - the hot water pipe runs above the cold one.
• There must be a slight slope, which, if necessary, will allow water to be removed from the pipes. The slope is directed towards the riser or water intake point.
• The distance between risers, pipes and the wall must be maintained.

Welding protection

How to weld water pipes using electric welding?

Start from the bottom center point of the pipe. To ensure that the ceiling welding stitch is smooth and of high quality, the electrode is drawn perpendicular to the welding site. From the bottom to the center to the top and symmetrically, on the other side, the same.

A vertical seam can be made pointwise, with the electrode positioned upward at an angle.

The horizontal section of the water pipeline is the most convenient and simplest for welding work. But, as with everything else, you need to be careful not to burn through the metal.

There are situations when welding needs to be done on a pipe close to the wall. In this case, a hole is cut in the pipe in order to make a seam along the inner wall, and then the rest of the joint is processed and a seam is made. Also, in difficult-to-see areas, so that the process is not done blindly, an ordinary mirror is used, which “shows” an invisible piece of pipe and electric welding is carried out based on the reflection.

Warmth in the house

Also, in addition to water, electric welding is used when installing a heating system, both in a private home and when installing individual heating in a high-rise apartment building. However, most often in the private sector. This is what we will proceed from.

Any global process, and heating is serious and difficult, must begin with preparation. The entire layout of the heating pipeline, the location of the boiler, bends, joints, bends, leading the pipe through the rooms through the walls, etc. are planned.

How to weld heating pipes using electric welding? The step-by-step process of electric welding is described above. But when connecting heating pipes, not only high-quality seams are important, but also correctly done wiring.

Pipe welding process

In order for the welding process not to turn into hell, but, on the contrary, to be simplified thanks to the thoughtfulness of all the nuances of the wiring (availability of connecting joints for welding work, convenience, minimum number of different bends and additional bends, etc.), it is necessary to consider the following points.

1. You can choose a single-circuit or double-circuit heating system, depending on what you ultimately want to get - only heating or also the presence of hot water.
2. Run the line in the attic or downstairs, along the walls.
3. If the communication is located at the bottom (and it is the most economical in terms of spending money), prepare holes in the wall for laying heating pipes through the rooms.

If all the above points are taken into account, you can proceed directly to the process of connecting pipes by welding.

1. First, all pipes are laid according to the chosen layout.
2. Then you can start welding, observing the slope (controlled using a building level) required for the slope.
3. First of all, the joints of the main line are made.
4. At the final stage, the boiler is “piped” with the installation of an expansion tank and pump.

Safety first!

Safety rules for welding work are described in the relevant GOSTs, but who will read these long provisions, written in compliance with all legal formalities. And yet. The process of electric welding is very responsible and dangerous, and therefore it is necessary to know those norms and rules that will preserve health and life! Here are the basic TB regulations.

1. The technology of the electric welding process should provide for maximum mechanization.
2. Necessarily! The presence of exhaust ventilation in a closed room or at home open windows or vents.
3. Necessarily! Availability of grounding (the welding machine comes with two wires, one of them with a tip that is used as a “ground”).
4. Good lighting of the room and areas where the pipeline will be welded.
5. Consumables (electrodes) must match the type of work to be performed. It would be good to purchase quickly cooling and filling electrodes (for home use).
6. Important! Use of personal protective equipment.

Source: http://ooo-asteko.ru/kak-zavarit-trubu-s-vodoy-pod-davleniem/

Do-it-yourself welding of steel heating pipes

When installing heating pipes, you often have to connect them by welding. Of course, in some cases a threaded connection may be suitable, but the percentage of this method is much smaller.

Welding metal heating pipes

As for welding steel pipes, this method has several varieties. For example: manual electric arc, gas welding (semi-automatic, automatic). To connect steel heating elements, the first type of welding is often used.

To weld steel pipes using manual arc welding, you need to use special electrodes that perform the function of an additive. They perform two functions: they conduct current to the arc and fill the seam. Their composition, dimensions and other characteristics are established by GOST. Today on the Internet you can find quite a few videos showing how this or that type of welding is performed.

Heating registers made of steel pipes.

The manual arc technology is quite simple, so you can do it yourself. It all starts with preparation.

Preparation

First you need to start preparing the pipes. Surfaces that are planned to be welded must be cleaned and degreased. This is the only way to avoid defects in the seams.

Products must have an appropriate opening angle of the edge; perpendicularity to the plane of the end of the product axis must be maintained. The preparation of large-diameter heating pipes is carried out using milling machines or gas-acid cutting.

Dimensions, compliance with the thickness of products, chemical composition, mechanical properties - everything must be combined with the requirements of GOST.

It should be noted that often the amount of blunting is about 2 mm, and the opening angle is about 65 degrees.

An important stage of preparation is the choice of materials.

Electrodes

Electrodes

You can weld steel heating pipes correctly if you choose the right electrodes. There are two types of them: non-melting and with a melting base. The gradation is based on the type of electrode core.

For the non-consumable type, electrical coal, graphite or tungsten is used. As for the melting one, it is made from welding wire, which can have different composition and size. In our case, electrodes with a diameter of 2 to 5 mm are often used.

Larger products can be cooked with a larger electrode diameter.

As for the coating, it also influences the choice of one or another electrode for welding steel heating pipes. There are such electrodes:

• With basic coating. Thanks to this consumable material, seams have a low probability of cracking and have good viscosity indicators.
• With rutile-cellulose coating. They are used for a variety of cases, including the most difficult one: a vertical seam from top to bottom.
• With rutile coating. The seams come out with excellent appearance. Slag is easily removed and ignition is easy. Therefore, such electrodes are often used for tack welds and fillet welds.
• With rutile acid coating. The slag is formed of a special structure; it is simply removed at the end of the process.
• Cellulose coated. Suitable for large diameter products, for creating vertical and circular seams.

Slag

This is a non-metallic alloy that weighs less than the products being welded. It is located at the top of the seam, forming a cover. Perform a protective function. The slag protects the seam from environmental influences. Once it cools and hardens, it can be easily removed.

Schematic diagram of welding metal pipes

If slagging of the seam is observed, this is a defect. After all, this reduces the strength of the connection.

Features of manual arc welding

It is carried out in several passes, after each it is necessary to remove the slag. Each subsequent seam is made overlapping the previous one. This method allows you to achieve maximum tightness and reduces the likelihood of fistulas.

Potholders

You should start welding heating pipes with tacks. This is the technology of butt connection.

They are part of the seam. To perform them, electrodes of the same type are used that will be used for main welding.

If the diameter of the products is up to 30 cm, you can make four tacks, evenly spaced. Length – 5 cm, height – about 3 mm.

You can butt weld a large diameter product by making tacks every 25-30 cm. Welding is performed in three layers if the wall thickness is up to 1.2 cm. You should strive to ensure that most of the joints are made in a rotary position.

Rotary method

First, a seam with a height of about 3 mm is made, using electrodes with a diameter of 2-4 mm. Then electrodes with a larger diameter are selected to create subsequent layers.

The seam

Welding large diameter heating pipes

The joint should be divided into four sectors. They are performed in two sectors in the upper hemisphere of the pipe, gradually rotating the product. And only the third layer is performed in one direction, rotating the pipe.

Nuances

If you are connecting products that operate under pressure, they are usually located near the walls of the room, so welding such pipes is not very convenient. The process begins at the lower section of the heating system, from the center.

The electrode should be positioned perpendicular to the welding site. If a vertical seam is being made, the electrode is placed upward at an angle.

After creating the layer, the slag must be removed.

If personal experience is not enough to perform such operations yourself, then it is better to turn to a professional. After all, the tightness of the entire heating system will depend on the quality of the welds. And for this you need to take into account many nuances, as well as have certain skills in handling a welding machine. As an addition to this, you can use video. And the rest is up to you.

Source: http://TrubyGid.ru/svarka-stalnyh-trub-otopleniya

Pressure welding technology for water pipes

Welding steel pipes is a responsible task, after which it is expected that they will work under pressure for a long time and ensure an uninterrupted supply of liquid for water supply or heating. Therefore, all seams must be performed with high quality, in compliance with the correct welding conditions for a specific situation. How are water pipes welded to minimize repair work? What to do if you need to weld a pipe that already contains water?

Competent execution of work

Pipeline welding technology, produced in accordance with the basic provisions, ensures long-term operation of the entire system. To do this, it is important to maintain slopes for the natural movement of the coolant. This way, you won’t have to redo the work twice.

It is also worth maintaining a sufficient distance from the walls and between the pipes so that it is convenient for the welder to weld the joints efficiently. For more reliable melting, a gap of 1-2 mm is left between the sides, into which the molten metal flows.

Welding of main pipelines is carried out in several passes to ensure tightness. The gas pipeline is also installed using the same principle. The welder performs the root weld using electric welding. It is important to achieve the formation of a reverse bead, which indicates good penetration of the sides. Subsequent layers are applied by automatic machines with filler wire and a layer of flux.

For better installation of the main pipeline, laser welding is used in the workshops, and only the last joints are made on site. Manual welding on pipes starts from the very bottom of the circle (in a horizontal position of the pipeline) and proceeds upward. The deposited metal is applied in “shelves” and raises the seam around the circumference to the highest point. This is done on both sides. The seam must be completed on solid metal. This prevents pores and fistulas.

When may it be necessary to weld a pipe with water?

Unfortunately, even if all the rules described above are observed, welding work may be required on a pipeline that has already been put into operation. Most often this is due to mistakes made by previous welders.

Perhaps poor eyesight did not allow the specialist to weld the joint properly, and the area began to leak. If a given pipeline supplies water to a large area that has already been shut off for a long time, then a repeat shutdown could cause a lot of complaints.

Therefore, it becomes necessary to perform welding under pressure.

It may also be necessary to weld a pipe with liquid in case of an emergency tap-in, when there is no time to drain the system, and all that can be done is to turn off the pumps to reduce the pressure in the system.

Either the area of ​​all communications with water is so large that it will take too long to wait for it to be emptied, or it is too expensive (to drain 20,000 liters of water for one seam).

Welded connections of pipelines can be complicated by the presence of liquid in the work area due to the special slope, which is provided for natural gravity flow. In this case, even after draining the system, water will continue to flow and interfere with welding work.

Many welders are afraid of welding pipes with water because it is a difficult task, fraught with long agony and does not guarantee a successful outcome. The application of molten particles of filler metal to a pore or fistula can lead to the “fouling” of the problem area with a whole pile of seams, from under which liquid will seep in all directions. Instead of one leak, you get many streams.

Why is it so difficult to weld a pipeline under pressure? There are several reasons for this:

• The water pressure constantly cools the weld pool, preventing the deposited metal from fully adhering to the base metal.
• The process is complicated by the constantly generated steam from the contact of the liquid with the heated iron. This makes it difficult to see the connection point. A welder's mask often fogs up on the outside.
• If the joint is on the ceiling, then the problem is aggravated by the fact that water flows onto the worker. Mittens and jacket are soaked. Since the welder has an electrode holder in his hands and stands on the ground (or holds the pipe with his second hand), this can provoke small electric shocks (safe, but unpleasant voltage up to 48V). It is very inconvenient to cook.

How to weld a pipe with water

The pipeline under pressure, as can be seen in the video, is successfully welded using electric welding. To do this, select certain modes and parameters, which are described below. But there are also small tricks, as well as technologies that help to perform this process correctly. Depending on the type of work required, different approaches are used.

Fighting fistulas

Due to non-compliance with welding conditions or a corrosive environment, a fistula may form in the pipeline. This is a small round hole from which water flows. The pipe may be mechanically damaged due to impact, resulting in a crack.

To successfully weld a problem area using electric welding, you need to stand in front of the problem area. This will make it easier to see all the boundaries of the hole. To prevent water from flowing down the electrode (in the case of a vertical or horizontal seam), you need to keep it perpendicular to the surface to be welded. The welding process is carried out from top to bottom. The goal is to narrow the fistula until it is completely closed.

To do this you need:

1. Place a few drops of metal on the top side of the hole edge.
2. Hit once or twice with a hammer immediately after the arc stops burning. This allows the deposited metal to penetrate deeper into the structure of the base metal, preventing the appearance of new pores. Additionally, the flattened ridges cover a larger area of ​​the fistula.
3. Apply a few more drops of metal, moving downwards.
4. Tap with the hammer again.
5. If the lateral edges of the fistula have thin walls, they need to be strengthened in the same way.
6. After steam has completely stopped seeping out, it is necessary to increase the pipe wall. This is done the other way around, from bottom to top, at low current, so as not to burn through thin metal. “Crescents” are applied in an intermittent arc until they are completely passed to the top point of the problem area.
7. It is advisable to tap the completed seam for hammering and compaction.

One-piece joint

In the case of connecting two sides of a pipe, one of which is still flowing water, a special approach can be used. This is especially true for pipelines running close to the floor or ground.

To successfully complete the work, a “window” is cut out in the upper part of the pipe, which is in a horizontal position. This is a rectangular or oval hole in one side of the connection. This will help in the case when the pressure is turned off and the main volume of liquid is released, but water continues to leak. A rag is placed in the pipe, absorbing moisture and freeing the bottom for unhindered dry welding.

The seam is applied from the inside through the cut out window. It is important to weld the bottom and raise the edges of the seam to the walls. For greater reliability, it is worth performing several passes.

Then the rag is removed (this is extremely important to do right away, otherwise all the work will be in vain if you forget it and weld the joint in a hurry), and the water flows along the already welded bottom without interfering with the process. Side seams are applied from the outside. The window is the last one to close.

This is done using a pre-prepared “patch” that is appropriate in size. Since the seam consists of several segments, all ends must be blocked, and the last crater must be brought out onto a solid section of the pipe and welded with surfacing.

If a tie-in is required

Welding of high-pressure pipelines can be performed if an additional fluid drainage channel is required. For example, another tank has been added, where water supply is required, or another heating branch has been built in the extension, and a coolant supply is required. If a tie-in is needed, but it is impossible to stop the system, then welding of a squeegee or ball valve is used.

This happens according to the following scheme:

1. A threaded pipe with a ball valve is fitted to the selected section of the pipe.
2. Without violating the integrity of the pipeline, the superimposed element is welded.
3. After this, the tap is placed in the open position and a hole is drilled through it in the main pipe.
4. Next you need to act quickly. Water rushes out through the newly formed outlet. The drill is quickly removed and the tap is closed.
5. A drive with a winding is connected to the counter thread of the tap and a new branch is closed.
6. The tap opens and the liquid supply starts.

This operation can be performed at any pressure. It is important to weld the pipe with the tap at a low current so as not to burn the main pipe. The diameter of the drill must be sufficient to transmit the volume and required pressure for the new branch to function fully.

Little tricks

To successfully weld fistulas and cracks with water, you need to know a few secrets that experienced welders use. Since water constantly interferes with the formation of the weld pool, it is important to reduce its impact. This is achieved in several ways.

First, you can drive a bolt into the fistula that has formed. To do this, select the appropriate diameter of the rod. As a result, instead of a hole from which water flows, a clogged hole with a cap convenient for scalding is formed. Of course, the liquid is not completely isolated, but its influence is reduced. It is necessary to gradually connect the walls of the base metal to the bolt head. The method is applicable in all spatial positions.

Secondly, the fistula can be repaired by welding a large diameter nut in its place. The latter is applied to the problem area and scalded. The liquid does not interfere, because it continues to flow freely through the hole in the nut.

After completing the welding work, a bolt with tightly wound tow is screwed into the nut. This seals the area.

The method has one drawback - the appearance of the repaired area is not very presentable (with a protruding bolt), but this allows you to quickly repair the leak and strengthen the thinned area.

The third trick is to increase the filler material. Since at one time the size of an applied “pea” of molten metal can cover a certain area of ​​the fistula, it is important to supply as much additive as possible into the weld pool.

This is regulated by the diameter of the electrode. But you can also use a second electrode, having previously beaten off the coating on it. The first electrode heats up the area, and when liquid metal appears, a second rod is added to it.

This increases the amount of deposition and promotes rapid closing of the water hole.

Modes

To carry out welding work on a pipeline in which liquid is present, it is important to set the amperage higher than normal for this position. This will allow you to hold the arc more steadily. The electrode will not stick due to rapid cooling with water.

It is important to calcinate the filler materials well. Of the common models, UONI 13/55 is suitable. They perform well in such conditions. It is advisable to heat the area with a burner to evaporate the leaking water. This will also have a more favorable effect on the penetration of the filler metal.

The type of tension also plays a role. It all depends on the personal preferences of the welder. Alternating current holds the arc well. They can be cooked under a large layer of water. But the quality of the seam itself is worse. Constant voltage is less stable when working in a humid environment, but the degree of penetration of molten material is higher.

Proper installation of the pipeline allows you to immediately obtain a high-quality system. But if there was a defect or the material has become leaky and repairs are required without draining the liquid, then the tips given in the article will help to cope with the problem.

Source: https://svarkalegko.com/tehonology/svarka-trub-pod-davleniem.html

Is it possible to weld heating pipes using electric welding and how to do it

Every owner of a country house and cottage should be able to handle a welding machine and work with metal. This device is required for all repair and installation work where metal pipes are present. It helps make the connection airtight. Expert advice will help beginners figure out how to weld heating pipes using electric welding correctly.

Working with electric welding

Surface preparation

Before electric welding pipes, you need to prepare them for the joining process. Surface preparation sequence:

1. Pipes must comply with all parameters specified in the project. They should have uniform wall thickness along their entire length, and the cut should be round.
2. The pipe is cut at an angle of 90° and cleaned to a shine at a distance of 1 cm from the cut.
3. Then the cut is degreased. To do this, remove all oil stains and clean off rust. If there is paint, it is removed.

If necessary, the end is further processed. The edge of the pipe cut should have an opening angle of 65° with a blunting value of up to 0.2 cm. Such a cut will help to qualitatively connect the products.

Types of welds and joints

Welding of steel pipes is carried out using a welding machine using the fusion method. The welding machine creates a constant current from alternating current and, through an electric arc, heats a local area of ​​the product to the desired temperature.

The formation of an electric arc occurs on a metal rod (electrode). Where the arc operates, a special atmosphere is formed, which, when melting the metal, does not allow it to oxidize. Thanks to a high-quality weld, leaks are completely eliminated, i.e.

because the connection is sealed.

There are many ways to apply sutures. Which method to choose depends on the thickness of the pipes and the material from which they are made. Main types of seams:

• to Taurus;
• end-to-end;
• overlap;
• corner.

It is also important to consider the location of the pipes in relation to each other:

1. Bottom seam. During welding work, the electrode is placed above the elements to be connected. With this method, the welder can clearly see all the welded areas, so this method is the most convenient.
2. Ceiling seam. The electrode is placed under the element to be welded. In this case, the operator raises his hand up and holds it above his head, so this method is used only during repairs or when replacing a deformed section of the pipe. It is not used when setting up a new system.
3. Vertical seam. This connection method is used if 2 pipes are located horizontally. The welder moves the electrode up and down and from bottom to top (in the vertical direction).
4. Horizontal seam. Often horizontal connections are used to install heating and plumbing systems. In this case, two pipes are in a vertical position.

Types of electrodes

An electrode is a thin metal rod that is coated with a special compound. It protects the metal from the occurrence of corrosive deposits and determines how the weld will turn out. To figure out which electrodes to weld pipes with, you need to consider the properties of each of them. The main parameters by which electrodes are classified are the type of coating and the type of core. Products come with a melting and non-melting core.

1. To make a melting core, welding wire with different diameters is used, which is selected depending on the type of work.
2. To make a non-melting core, tungsten, graphite or electrical coal are used.

The electrodes are coated with cellulose, rutile, rutile-acid or rutile-cellulose coating.

Selecting a welding machine

There are three types of welding machines. Which one to choose depends on the welding method and the material being processed. Device types:

1. Step-down welding transformers. This is a reliable device that is used for welding carbon steel. The quality of the seam is average.
2. Welding rectifiers. Suitable for carbon and aluminum materials, as well as stainless steel. The seam quality is high.
3. Welding inverters. A universal device that is suitable for any material.

You cannot use damaged equipment when welding heating pipes using electric welding. Therefore, before starting work, the equipment is carefully checked.

Work technology

First you need to prepare the workplace and protective equipment. To figure out how to properly weld heating pipes, you need to practice on a separate piece of metal. To do this, you will need a thick pipe and a universal electrode with a diameter of 3 mm and above, since it is easier to learn how to make seams with it. Work process:

1. One welding cable has a holder. An electrode is inserted into it, then the cables are connected.
2. The device has 2 cables and 2 current outputs with positive and negative polarity. The end of one cable is equipped with a clamp that connects to the part, the end of the second is a holder for the electrode. Polarity is chosen depending on the type of work. The best heating of the metal occurs with straight polarity.
3. There are 2 ways to light an arc. To do this, the tip of the electrode is tapped several times on the part or drawn along the seam (chirping).
4. The type of weld on the pipe depends on the inclination of the electrode. The main inclination is 30-60°. To deeply heat the metal, the electrode is tilted at a “backward angle.” In this case, the bath and molten metal flow behind the electrode. If surface heating is required, then the angle of inclination is changed in the opposite direction.

Each material and type of seam has its own electrode movement.
For homework, it is enough to master some of them. During work, it is important to monitor the size and condition of the weld pool. To do this, movements are accelerated or slowed down. How to weld pipes quickly and easily for novice welders

How to weld plastic pipes

Welding of plastic pipes takes place using a special technology, because due to the high temperature, sagging often forms inside them. Therefore, welding work must be performed carefully. But if the temperature is too low, the parts will not be fixed. Work order:

1. The welding machine is placed on a stand and heated to 260° C.
2. The end of a plastic pipe and a fitting of a suitable diameter are inserted into the welding nozzle so that they are located in the same plane.
3. If the pipe is thick, then the temperature level is increased. When the parts warm up, they are removed from the device and connected.

When the seam hardens, the pipe is checked for leaks. Products with a large diameter (over 63 mm) are soldered joint-to-joint. The cut of the end pipes is melted and connected, while pressing strongly on each other. For coupling and socket soldering, hand-held instruments are used. They are equipped with a centering element and attachments that hold the workpieces. All pipeline parts are driven into a heated welding machine and soldered. To ensure that the parts are connected, all work is carried out quickly.

Possible errors in the process

The quality of the finished product may be poor due to a defect in the weld. The defect can be located inside or outside the product, and can also be through. The reasons why it occurs during welding of metal heating pipes and other products:

• due to cheap low quality material;
• due to poor quality equipment;
• when the technological process of work is disrupted;
• due to the inexperience of the welder.

Sometimes welders reinforce the seam up to 4 mm. Because of such an error, it becomes fragile. The height of the reinforcement should not exceed 2 mm, then the seam will have maximum strength.

Source: https://trubyda.ru/svarka/elektrosvarka

How to weld a pipe with water using electric welding

27.03.2019

Situations arise when a defect in the pipeline has to be repaired when supplying water. More often, fistulas occur on welded pipes; they can be eliminated by electric welding the water pipe using surfacing electrodes. Although the welding will be weak, a serious accident, water leakage will be prevented.

Before welding, the main pressure is reduced to possible limits. Experience is required to perform the work. A beginner cannot cope with such welding. It is especially difficult to weld cast iron risers. Cast iron has high fluidity; when heated, structural changes occur in the metal, worsening performance characteristics.

Welding water pipes under pressure using electric welding

Why is it necessary to weld a pipe with water?

It is necessary to boil pipes with water in the following situations:

• when, after putting the system into operation, lack of penetration of joints is detected;
• sometimes when installing welded pipes, the main line turns out to be defective;
• when it is impossible to leave a large area without water;
• there is no way to drain the water or it is not economically feasible;
• you urgently need to install a shut-off valve or metering unit;
• Due to the slope, water remains in the pipe after the system is drained.

These are not all situations in which welding of pipelines with water is necessary.

Features of welding water pipes

You can weld a pipe with water using electric arc, gas welding, or semi-automatic welding using surfacing wire. Electric welding of a water pipeline filled with water is associated with some features:

1. The welding operating mode when sealing defects and water leaks is adjustable. If there is no risk of burns through a wall thinned by rust, the current strength when welding a cold water system filled with water is increased by 5–10%, depending on the type of alloy. By cooling the wall, the electrode will not stick to it during welding. Depending on the type of welding machine, welding is carried out using alternating or direct current. Variable is preferable; the arc during welding will be stable. The connection is formed even under a thick layer of water. If you need a high-quality seam, use direct current. Although the welding voltage will be unstable, the molten weld metal will penetrate deeper into the defect area when welding a pipeline with water.
2. For operation, electrodes are selected according to the type of pipeline material. NZh-13 is suitable for welding stainless pipes, MNCh-2 or OZCH-2 is suitable for repairing cast iron risers, or you can weld gray high-carbon cast iron. When using an inverter as a current source for repair work on water pipelines, MR-3s, TsCh-4 electrodes are purchased; they melt at low currents and have a low melting point. The electrodes are pre-calcined, heated to 200°C and held for 40 minutes to an hour.

Source: https://svarkaprosto.ru/tehnologii/kak-zavarit-trubu-s-vodoj-elektrosvarkoj

How to weld a squeegee to a heating pipe?

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.

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: https://gscomplect.com/kak-privarit-sgon-k-trube-otopleniya/

How to weld a leaking pipe using electric welding? Pressure water pipe repair!

Electric welding of water pipes is one of the most reliable ways to achieve the necessary tightness of the circulation circuit. The seams obtained using this technology are resistant to pressure, mechanical loads, and corrosion.

Unfortunately, even if all requirements are met, pipes may leak during operation. This occurs due to external loads for which metal structures are simply not designed, as well as due to natural aging and wear of the material.

In such a situation, you have to act immediately and eliminate leaks in an already used pipeline.

Need for work

Welding a pipe with water may be required in the following cases:

1. Leaks formed as a result of exceeding standard loads or poor-quality installation work. Disconnection in such cases is not welcome, especially if we are talking about main pipelines supplying water to large residential areas.
2. The need for a tie-in. Draining liquid from the entire system involves significant temporary losses, so the matter is often limited to turning off the circulation pumps. This measure helps reduce pressure in the circuit, making work easier.

Main difficulties

Welding pipes under pressure is not an easy task, and not every specialist will undertake it.

Problems are associated with the following phenomena:

• the pressure of the liquid does not allow the required temperature of the weld pool to be reached, it is extremely difficult to achieve the required coefficient of adhesion of the deposited metal to the base;
• When water comes into contact with hot material, large volumes of steam are produced. The welder has to work in conditions of limited visibility, the mask fogs up, he has to constantly wipe it, get distracted, waste time;
• It is very difficult to work when the pipes are located at a height, under the ceiling. Water can drip onto the welder, and it can be awkward to hold heavy equipment.

Selecting a tool and setting up equipment

Despite all the difficulties, working with pipes under pressure is quite feasible. The main thing is to correctly adjust the operating modes and select the appropriate tools.

For example, the best electrodes for welding water pipes are as follows:

SSSI 13/55. Universal elements that allow you to repair pipes made of steel, regardless of the degree of alloying and carbon content.

The formed seam is characterized by an optimal combination of strength, ductility and toughness, and can withstand high operating loads without the formation of repeated fistulas and destruction. Beginners may be afraid that the electrode sticks to the metal during operation, but it is very easy to get rid of this; you just need to lengthen the arc.

In just a few minutes of work you can develop a good skill and feel all the subtleties and advantages of the electrode.

MGM-50K. New development optimized for work with pipes under pressure.

The main feature is that a gas bubble is formed around the arc, displacing steam or liquids, which improves the conditions in which welding is carried out, facilitates the task, and allows one to achieve the desired result.

The electrode is suitable for working with pipes made of both high carbon steel and low alloy grades. It is allowed to work on contaminated surfaces and metal that already has signs of corrosion damage.

Watch an interesting video about which electrodes are best to use for welding pipes:

It is also useful to adhere to the following recommendations:

1. Increasing the current will help achieve the required arc stability; the likelihood of electrode sticking will be reduced due to the fact that the deposited metal quickly cools and sticks to the base.
2. The electrodes are pre-heated, and the work area is heated with a gas burner. The flame evaporates the liquid leaking from the pipe, increasing the level of adhesion of the deposited metal to the base.
3. When choosing voltage, you should focus on your own preferences.

Beginners should know that:

• alternating current forms a more stable arc, making it possible to work even under an impressive layer of water, but the final quality of the seam is not too high;
• direct current, in turn, helps to achieve maximum penetration depth of the deposited metal and weld strength, but direct work in an environment of high humidity is more difficult.

Source: https://plavitmetall.ru/svarka/kak-zavarit-trubu-s-vodoj.html