What is welding definition - Metals and their processing

What types of welding are there (description and advantages)

So, inverter welding - what is it? Essentially, inverter welding is a process that uses a circuit, system, or device whose job is to create an alternating voltage using a direct current source.

Inverter welding

The general circuit of such a welding machine includes a mains filter, mains rectifier, frequency converter, high-frequency transformer, power rectifier and control system.

Naturally, in order to weld metal structures, it is not enough just a welding machine; you will also need to use various accessories - a mask, holders and, of course, electrodes. Welding without electrodes is simply impossible. In the process of inverter welding, three types of electrodes are used - carbon, alloyed and high-alloyed.

The main advantages of welding work using an inverter machine are as follows:

ignition is easy and quick, the arc burns steadily and has good elasticity;
high quality weld;
low energy costs during operation;
fairly good efficiency;
supply voltage fluctuations do not affect the quality parameters of welding joints;
These devices are lightweight and mobile.

Naturally, like any process, inverter welding also has its disadvantages: inverter-type welding machines, like any complex electronic devices, are highly susceptible to the influence of water, dust and frost. For this reason, devices of this type must be stored in a room that provides the required parameters of dryness and warmth.

Another important point is the care of the welding machine; periodically it will be necessary to open the housing and blow through the components of the device with compressed air.

Argon welding

Argon welding is one of the types of welding work that allows welding complex and refractory metals. Using this welding method, aluminum and other metals that undergo an oxidation process when exposed to air are often welded.

Argon welding is most often used in industries such as the automotive industry, during the repair of various vehicle components made of aluminum. In addition, argon welding is used in the metallurgical industry, for example, to carry out hot processing of titanium, tantalum, niobium, beryllium, zirconium, hafnium, tungsten, uranium, thorium and to process alkali metals.

The use of argon as a gas is a fairly common practice; for example, light bulbs also contain it.

Argon welding is a rather complex process that requires high qualifications and modern equipment. However, the result of this process is at the same level - the seams are smooth, sometimes almost invisible, and at the same time very durable.

Argon-arc welding is carried out using tungsten electrodes and a ceramic nozzle. It is through this nozzle that argon is supplied to the welding site, which prevents the metal from coming into contact with the atmosphere. This, in turn, prevents oxidation of the metal and ensures a strong weld.

Argon welding can be divided into two types: manual welding and automatic

So what is good about argon arc cutting and welding of metal structures? To begin with, it is worth noting that due to the fact that this process uses modern equipment, the operating time is significantly reduced. In addition to this, the argon jet during welding work, in addition to protecting the metal from the influence of air, also blows away everything unnecessary and unnecessary.

Lastly, but most importantly, this type of welding work is very economical. This is due to the fact that with the help of argon, the electric arc is compressed and concentrated in a narrow area. For this reason, with relatively low energy costs, it is possible to reach a temperature of the cutting zone of the order of 40006000°C.

Argon arc welding

If you need to weld a steel structure, then, without thinking twice, you will pick up a welding machine and easily cope with this task. But what to do if welding work needs to be done, for example, for an aluminum structure? This is where argon arc welding can help you.

Argon arc welding is welding using an electric arc in an inert argon environment. Consumable or non-consumable electrodes can be used for this welding. A tungsten electrode is most often used as a non-consumable electrode.

The arc burns from the workpiece being welded to a non-consumable electrode (as already mentioned, most likely tungsten). The electrode is fastened to the burner, through the nozzle of which protective gas is supplied. The filler material is supplied to the arc zone from outside and is not included in the electrical circuit.

Argon welding can be performed in manual mode, when the welder controls the torch and filler rod, and in automatic mode, when the movement of the torch and filler wire is carried out without the help of a worker.

When welding with a non-consumable electrode, unlike welding with a consumable electrode, during ignition of the arc the electrode does not touch the product for such reasons. To begin with, argon has a high ionization potential, for this reason ionization of the arc gap using a spark from the electrode to the product is a rather difficult task.

In the case of argon welding using a consumable electrode, after the wire touches the part, the arc zone is saturated with metal vapors, which have an ionization potential almost three times lower than that of argon, as a result of which the arc is ignited.

In addition, if the part touches the tungsten electrode, things such as contamination and intense melting will occur. For this reason, during argon welding using a non-consumable electrode, a device called an “oscillator” is connected in parallel to the power supply network to ignite the arc.

Using an oscillator, to ignite the arc, high-frequency high-voltage pulses are supplied to the electrode, ionizing the arc space and ensuring ignition of the arc when the welding current is turned on. If argon welding is performed with alternating current, when the arc is ignited, the oscillator begins to work as a stabilizer, supplying pulses to the arc when the polarity changes.

This is necessary to prevent deionization of the arc space and ensure stable arc combustion.

During DC welding, the anode and cathode produce different heat. When currents are less than 300 A, the anode generates more heat than the cathode, 70 to 30 percentage, for this reason straight polarity is usually used to ensure maximum penetration of the part and minimal heating of the electrode.

When welding all steels, titanium and other materials except aluminum, straight polarity is used. When welding aluminum, alternating current is used to improve the destruction of the oxide film.

Argon is sometimes mixed with 3–5% oxygen to reduce porosity. This causes more active protection of the metal. Argon in its pure form protects the metal from phenomena such as moisture or other inclusions that enter the welding zone. And with the help of oxygen, harmful impurities are burned out, or released outside. And this helps fight porosity.

Semi-automatic welding machine without gas

If you decide to buy a semi-automatic welding machine without gas, then most likely you are already faced with a huge variety of different options on the market. Let's try to figure out what this device should look like in general.

The welding machine must be inexpensive and powerful. It is best for it to work semi-automatically, from direct current using a melting wire. It is desirable that in the machine, in addition to the mode of operation without gas on flux-cored wire, there is also the possibility of operating on gas (carbon dioxide and argon).

An important factor is the choice of the manufacturer. The manufacturer of the device you choose should be among the leaders in such areas as industrial and household production of equipment for welding work. This company must be officially represented on the market of your country, and have all quality and safety certificates, as well as have service centers.

The wire feed should be adjusted smoothly. It should be possible to implement stepwise power adjustment of welding currents from 50 to 140 A. Even a 5-kilogram spool of wire should be placed in the machine. The device must be equipped with thermal protection and forced air cooling. The machine must be able to operate with power from weak networks.

The winding in the device transformer must be made of copper. The device must be multifunctional; in addition to being used at home, the device must also cope with industrial needs (for example, a repair shop and service station). It would be good if the device is equipped with wheels for ease of transportation.

Well, lastly, and most importantly, when choosing a semi-automatic welding machine without gas, go to the Internet and carefully study the reviews of this device from people who have used it and who have something to compare with.

Source: http://postroyka-dom.com/kakie-vidy-svarki-byvayut-opisanie-i-preimushhestva/

Features and characteristics of welding types

The life of a modern person is closely connected with things made using welding technologies. We are talking not only about joining metal, but also other materials that can be joined at the molecular level. The article will discuss the main types of welding.

Process concept

Welding is a technology for creating a permanent connection between two surfaces through intense temperature exposure.

Physical signs

Metals have a high melting point. Without additional area factors, the contact parts of the welded products will not interact with each other. To change the state of aggregation of a metal, it is necessary to increase its temperature. Upon reaching a certain level, conditions are created under which it becomes possible to join parts to obtain a strong interatomic bond between the surfaces.

Manufacturability is the main property of welding work

The types of welding used depend on the characteristics of the work parts, as well as production conditions. The most commonly used technologies are:

Dugovaya.
Plasma.
Gas.
Pressure welding.
Butt.
Cold.

Importance of properties

In the process of joining workpieces, it is necessary to ensure reliable protection of the temperature-affected zone from the aggressive influence of oxygen in the atmosphere . Otherwise, corrosion processes will actively develop in the processing area, deteriorating the quality of the structure. The main ways to prevent contact of the melt with air:

flux;
vacuum;
protective gases;
foam.

Classification

The classification of metal welding is carried out based on the nature of the impact on the plane:

Thermal class . It is characterized by a non-contact method of influencing the surface - an electric arc or a gas flame.
Thermomechanical class . This type of welding combines non-contact action to achieve the desired temperature, as well as mechanical pressure to complete the connection.
Mechanical class . The specified thermal parameters are obtained solely through mechanical action on the products being connected.

Below we will discuss the types of welding and their brief characteristics for each class.

Welding arc

A welding arc is a source of thermal energy for molten metal . It is an electrical discharge that occurs when a circuit breaks. Devices operating on direct or alternating current are used as a power supply mechanism.

Electric arc

Electric arc technology is the most common method of joining metal products . It owes its popularity to the relative simplicity of the equipment used and the low cost of performing the work. There are several types of arc welding.

Manual arc

The work is carried out using flux-coated electrodes and a welding machine . The method got its name due to the functions performed by the welder:

Selecting the direction of movement of the rod and its speed.
Arc length;

When exposed to high temperatures, the flux melts. Some components enter the melt zone, improving quality characteristics, while others remain on the surface, forming a protective film.

Non-consumable electrode

Refractory elements are used as electrode material: tungsten or graphite . The melting point of the base surface is lower than that of the electrode. This circumstance increases the service life of the rods. The use of filler metals is acceptable. Due to the absence of flux, work is carried out in an inert gas environment.

Mechanized with a consumable electrode in a protective gas environment

This type of work is characterized by the use of a special filler material - electrode wire, the composition of which depends on the properties of the working surface . Feeding mechanisms are used to feed material into the welding zone.

They can be either one of the units of the unit or stand-alone equipment. The wire does not have a protective coating, so the connection is made under gas protection. In its absence, a special type of additive is used - flux-cored wire, which contains flux to protect the seam.

For work, devices that operate in semi-automatic mode are used.

Submerged

In this case, a flux composition is applied to the joint zone, which, when melted, creates a gas bubble that serves as a barrier to harmful atmospheric factors . Complies with the requirements of GOST 8713-89. In serial production there are installations that perform submerged arc welding in automatic mode.

Electroslag

A special feature of the method is the thermal energy supply system: current passes through the flux, heating it . Then the melting of the filler material and the workpiece occurs. The method is indispensable for vertical connections with a recess relative to the main plane.

Orbital

A method for industrially joining circular surfaces such as pipes . There are two ways to implement permanent communication. In the first case, the workpieces rotate around their axis. Under the influence of friction force, the operating temperature is reached. In the second case, the products are fixed, and the movable head of the arc welding machine rotates around them. In this case, electrode wire is used.

Gas-flame

The technology is characterized by the use of thermal energy generated during the combustion of combustible gases and their mixtures . Depending on the mass fraction of oxygen, the nature of the flame is determined. It can be of three types:

oxidative;
neutral;
restorative.

Plasma

The working tool is a plasma torch that generates a high-temperature plasma arc . Electromagnetic forces are used as a jet regulation mechanism, increasing the speed of ions to the required value. In addition to welding, plasma is used in surfacing, cutting and spraying.

Electron beam

A high-tech method characterized by the principle of surface heating - an electron gun is used to increase the temperature, which creates a flow of electrons . The elements are connected in vacuum chambers.

Laser

The joint area is exposed to a thin laser beam, which is characterized by precision processing and little influence on the area around the seam . This helps to avoid deformation when working with thin sheet materials. Experts recommend welding structures in a protective gas environment.

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Reflow butt method of joining plastics

As the name suggests, a Teflon-coated heating element is used to melt plastic products.

With embedded heaters

Another method of joining polymers. Heating is carried out by resistance elements that are installed on the coupling. After mounting the workpiece, an electric current is applied, melting the plastic.

Kuznechnaya

A forging hammer was used as a working tool, deforming workpieces . Is the oldest way to perform a connection. Currently practically not used.

Contact

The most popular method of this class. The work cycle includes two stages. The first is melting the surface to a plastic state. The second is pressure on the heated elements, which can be carried out either manually or using various drive mechanisms. Subtypes of contact technology are:

Spot

A popular technology that can be implemented at home. The product is placed between two rods that act as electrodes. They are supplied with a short-term pulse charge, which heats the plane. The workpiece is then compressed by electrodes, forming an interatomic compound.

Butt

The main difference between the technology is the width of the impact on the surface. The connection is made along the entire contact plane. There are two ways to create a connection:

resistance;
continuous reflow.

Embossed

The method is characterized by specific preparation for welding. Elevations called reliefs are pre-installed on the contact planes . After joining the points, an electric current is applied to them, which causes deformation of the reliefs.

Diffusion

The technology is based on the phenomenon of diffusion - the mutual penetration of particles into each other . As the temperature rises, the intensity of atomic movement increases, creating optimal conditions for connecting parts. The process takes place in an airless environment or in a protective gas environment.

High frequency currents

The metal melts under the influence of high frequency currents. After crystallization of the treated area, a strong weld is formed.

Friction

The main advantage of this joining method is the ability to work with dissimilar metals . According to technological requirements, one workpiece must be securely fixed in a special support. The second one is spun around its axis and connected to the first one under pressure. The thermal energy released due to friction is sufficient for the formation of new molecular bonds.

Explosion

The main method for producing bimetallic compounds. To sinter blanks, thermal energy is used, which is released during an explosion.

Ultrasonic

This method uses ultrasonic vibrations to form permanent bonds between atoms . The uniqueness of the technology lies in the ability to weld various materials, from metal to leather or glass.

Cold

A unique method of welding materials, which is characterized by a low operating temperature, below the level of recrystallization of the metal structure . Technological requirements include careful preparation of the working plane. It must be cleared of foreign elements. Immediately before the start of the cycle, the surface is degreased.

This pressure welding is used to work with materials that are sensitive to temperature changes.

International designations

When performing work in Russia, in construction and other industries, all welding processes are subject to the requirements of GOST R ISO 4063-2010. This is a domestic analogue of the international standard ISO 4063:2009.

In art

Artistic welding is a recently emerging art direction . A master who creates sculptural compositions is called an art welder. In Moscow and other large cities, numerous exhibitions are held that introduce connoisseurs to new works.

It is safe to say that every year more and more people are interested in artistic metal welding.

Conclusion

The article explained what types of welding there are: from electric welding to ultrasonic joining.

Source: https://svarka.guru/vidy/osobennosti-i-harakteristiki.html

Types of welded joints and seams: description, technological features, requirements and GOST:

In order to learn how to cook well, it is not enough to master just holding the electric arc. In addition, you need to understand what types of welded joints and seams there are.

Beginning welders often make serious mistakes, for example, not welding the metal. And it happens that finished parts have weak fracture resistance. What is the reason? First of all, in the wrong choice of connection type, errors in technology.

Today we invite you to talk about different types of welding, types of welded joints, as well as defects!

Weld seam: definition

First, let’s define the definition of a weld seam. This is the name given to crystallized metal that was in a molten state at the time of welding.

The structure of the weld seam includes:

deposited metal zone;
mechanical fusion zone;
heat affected zone;
transition zone to the base metal.

Welded joint: what is it?

A welded joint is usually defined as a limited section of a structure that contains one or more welds. It is by the appearance of the connection that a specialist can determine the qualifications of the welder and understand what welding method was used. The welded connection also tells about the technological purpose of the structure.

Welds: classification

Experienced welders say: the classification of weld types can be based on a variety of factors, for example structural and strength, geometric and technological. If we consider the seams from the point of view of location, they can be divided into lower, inclined, horizontal and vertical.

The bottom seam can be called not only the simplest, but also the most durable. The fact is that the gravity of the metal makes it possible to better fill the gaps between the surfaces being connected. In addition, this type is the most economical. There are certain conditions, for example, the burner or electrode must be directed from top to bottom.

A horizontal seam is usually formed when the surfaces are perpendicular to the plane of the electrode. The consumption of fluxes and electrodes with this type increases significantly. If the seam is drawn slowly, drips may occur, and if the seam is drawn quickly, uncooked areas may occur.

It is much more difficult to make a high-quality vertical seam. Here, metal loss increases, unevenness increases (at the final stage of welding, the seam turns out to be thicker). This method requires a certain classification of the welder. It is usually used for welding pipes or when fastening large structures.

Welders consider ceiling welding to be the most difficult. How is it produced? The seam is applied with an intermittent arc. The current strength is small. This type is usually used when welding pipes that cannot be turned.

Welded joints: types and types

We propose to talk about what types of welded joints there are according to the types of joining surfaces. Depending on factors such as the thickness of the metal, the geometric shape of the parts, and the required tightness of the joint, welded joints can be divided into:

T-bars;
overlap;
butt;
corner.

All types of welded joints have their own purpose, which suits the specific needs of the finished elements. We invite you to consider these types in more detail!

Joint

The most common type of welded joint is a butt. It is used when welding the ends of pipes, steel sheets or any geometric shapes.

The parts that are joined end-to-end differ in the thickness of the product and the side of the seam. Several subtypes of connections can be distinguished:

unilateral normal;
one-sided, in which the edges are processed at an angle of 45 degrees;
one-sided, in which one edge is processed at an angle of 45 degrees;
one-sided, in which the edge on both parts is removed with a milling cutter;
double-sided, which involves cutting the edges at an angle of 45 degrees on each side.

It is important to note that with this type of welded joint, the thickness of the welded surfaces plays an important role.

If it is no more than 4 millimeters, then a one-sided suture is used, but if the thickness exceeds 8 millimeters, the suture must be applied on both sides.

If the thickness of the product exceeds 5 mm, but the seam needs to be applied only on one side, thereby obtaining high strength, the edges should be separated. You need to do it with a file or grinder; a 45-degree bevel is enough.

Gusset

There are several corner connection options:

one-sided - both with and without preliminary cutting;
double-sided - regular and with cutting.

Using this connection, you can fasten two elements together at any angle. In this case, the first seam will be internal, and the second - external. This type is ideal for welding various canopies and canopies, truck bodies and gazebo frames.

If you need to connect two plates of different thicknesses, this type of welded joint according to GOST must be performed as follows: the thicker plate should be placed at the bottom, and the thinner should be placed on it edgewise. In this case, the electrode or burner should be directed at the thick part - this way there will be no burns or undercuts on the part.

Lap joint

Two plates can be welded not only end-to-end, but also overlapping - by slightly pulling one onto the surface of the second. Experts recommend using this type of welded joint where greater tensile strength is required. The seam must be placed on each side - this will not only increase strength, but also prevent the accumulation of moisture inside the finished product.

T-joint

This type is similar to a corner connection, but there are differences - the plate, attached with an edge, should not be placed at the edge of the lower base, but at a short distance.

Classification by technology and seam shape

Welders distinguish between types of welded joints based on the type of welds. The seam can be:

Smooth. It is achieved with optimal settings of the welding machine and with its comfortable position.
Convex. Such a seam can be obtained with low current and passing through several layers. A convex seam requires machining.
Concave. Such a seam can only be obtained with increased current strength. This type of weld has excellent penetration and does not require grinding.
Solid. To make a high-quality continuous seam, you need to do it continuously. This will prevent the occurrence of fistulas.
Intermittent. This seam should be used for products made from thin sheets.

A welder who is familiar with the main types of joints and their fundamental differences can correctly select the type of weld that can satisfy the basic requirements for strength and tightness.

Defects in welded joints: types, description, causes

Welded joints can have various effects that affect strength and sealing. It is customary to divide all types of defects into three categories:

internal (these include lack of penetration, porosity and foreign inclusions);
external (including cracks, undercuts, craters, sagging);
through (here you can highlight burns and cracks).

Let's talk in more detail about each type of defect.

Cracks

This type of defect is considered the most dangerous; it can lead to rapid destruction of welded structures. Cracks are distinguished by their size (there are macro- and microcracks) and by the time of appearance (during the process of welding parts or after). The reason for the appearance of cracks is non-compliance with welding technology, incorrect choice of materials for welding, or too rapid cooling of the structure.

You can fix a crack as follows: drill out its beginning and end, remove the seam and weld it.

Undercuts

Undercuts are the depressions between the seam and the metal. The seam becomes weak due to this defect. The reason for the appearance of undercuts is an increased current value. An undercut usually occurs on horizontal seams. This defect can be eliminated by surfacing a thin weld along the undercut line.

Surges

Such a defect can appear when molten metal flows onto the base metal without forming a homogeneous compound. The reasons for the appearance of sagging are simple - the base metal is not heated, the welder uses an excessive amount of filler material. The defect can be eliminated by cutting, making sure to check for lack of penetration.

Burns

Burn-throughs are defects that manifest themselves in through penetration and leakage of liquid metal. In this case, on the other side, as a rule, a sag appears. The cause of burn-throughs is high welding current, slow movement of the electrode, insufficient thickness of the lining, or too large a gap between the edges of the metal being welded. You can fix a burn-through: just clean and weld the defect area.

Lack of penetration

Lack of penetration refers to local lack of fusion of the deposited metal with the base metal. Lack of penetration can also be called non-filling of the seam section. This type of defect reduces the strength of the seam and causes destruction of the finished structure. The reason lies in the low welding current, the presence of slag or rust on the parts being welded. To correct the error, you need to cut out the lack of fusion and weld the parts.

Craters

The depressions, called craters, are usually caused by a broken welding arc. If such a defect appears, it is necessary to cut it down to the base metal and carefully weld it.

Fistulas

This is the common name for cavities that reduce the strength of the seam. It is because of fistulas that cracks can form. Cutting out the defect and welding will correct the situation.

Porosity

What is porosity? These are cavities that are filled with gases. The reason for their appearance is intense gas formation inside the metal. Pore sizes can be either microscopic or reaching several millimeters. To avoid porosity, the metal should be cleaned of dirt and foreign substances. It is necessary that the electrode is not wet. If a mistake has already been made, the porous zone should be cut out to the base metal and welded, following the technology.

Overheating and burnout

These defects appear as a result of high welding current or insufficient welding speed. Because of this, the finished product becomes very fragile. Burnt metal can only be cut out, and the metals can be welded again.

Welding control

Now let's look at the types of inspection of welded joints. The following methods exist:

visual inspection;
chemical analysis;
transillumination with gamma rays or x-rays;
metallographic analysis;
ultrasonic or magnetic flaw detection;
mechanical tests.

There is a very important rule - for reliable control, it is imperative to clean the joint from slag, scale and welding spatter!

Source: https://www.syl.ru/article/364740/vidyi-svarnyih-soedineniy-i-shvov-opisanie-tehnologicheskie-osobennosti-trebovaniya-i-gost

Do-it-yourself technology for concreting a yard in a private house

In many cases, the garden area is developed by simply concreting the yard. This is a fairly cheap and practical option to get good coverage.

If you want to improve your yard in this way, just follow the simple recommendations of experienced craftsmen, which will be given in this article. We’ll figure it out and show you how to concrete a yard in a private house with your own hands, so that the result will please you for many years.

Decorative concreting of the site

Stages of work

The process includes the following steps:

Excavation.
Arrangement of a drainage system.
Installation of formwork.
Waterproofing works.
Reinforcement.
Installation of beacons.
Pouring the concrete mixture.
Surface treatment during hardening of the concrete mixture.

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The steps must be clearly followed. This is the only way to guarantee high-quality coverage.

Excavation

The progress of the process depends on the characteristics of the soil and the topography of the land plot. The yard must be marked, the surface leveled, then crushed stone added. The layer of earth is removed so that the concrete surface is level with the earthen surface - approximately 25 cm.

Preparing the site for concreting

If the base consists of clay, crushed stone may not be added. The fertile soil is removed and sent to the garden, where it will be really useful.

Drainage arrangement

The layer is needed to remove moisture from the concrete surface, since the presence of liquid in the ground negatively affects its strength characteristics. The system is performed as a bedding containing sand and crushed stone. First you need about 5 cm of sand and compact it well.

The second layer is laid with 7 cm of crushed stone, after which sand is poured. Tamping is not performed. You just need to level the layer well. To fill the drainage, you should use fine/medium fraction material. Large stones will not settle down immediately; they will shrink over time. For this reason, cracks appear in the concrete surface over time.

Tamping the pillow

Installation of formwork

A flat building material is used, one of the sides of which is smooth. Suitable for this purpose:

boards;
plywood;
chipboard;
flat slate.

To fill a curved path, sheet plastic should be used. The installation of the structure is carried out along the edge of the territory that was dug/marked during the work. The structure is secured with stakes that are driven in on both sides. Formwork components placed opposite each other can be pushed apart.

Waterproofing layer

The device uses standard polyethylene film. Suitable waterproofing, roofing felt. The arrangement is carried out to prevent moisture from entering the concrete layer from the ground and to eliminate water leaving the concrete immediately after pouring. Waterproofing also prevents plants from growing through the concrete in the future.

Geotextiles for waterproofing

Reinforcement

Performed to add strength to concrete pouring. The reinforcing mesh is made of metal mesh with a wire thickness of at least 6 mm. The cells must have a size of at least 10 cm. The mesh is laid in finished sheets overlapping. If there are metal rods with a diameter of over 8 mm and similar materials, reinforcement can be performed using them. The metal is placed on crushed stone. Connected with knitting wire.

Installation of beacons

The work is carried out to determine the upper level of the site when screeding and pouring concrete mixture. A metal profile is used for installing drywall sheets.

Concreting a parking lot

Beacons are installed across, not along, the site. When using a level, it is worth installing several of them around the edges. Fastening is carried out in slides made of sand-cement mortar. Gypsum solutions should not be used for this purpose.

After the solution has set, several cords are stretched between these beacons, along which other beacons are placed. This way they will be on the same level. On platforms, beacon slats are placed lengthwise in pairs.

Concreting the territory

When thinking about how to fill a site with concrete with your own hands, you need to know the conditions under which this process occurs and the requirements for it.

The pouring process is considered difficult and simple at the same time. Work should be carried out at an ambient temperature within 5-25°C. For concreting, you can purchase ready-made concrete or make a concrete mixture to save money.

Arrangement of technological gaps

Before pouring, technological gaps are made, which are otherwise called expansion joints. If the temperature changes outside, they allow you to compensate for the thermal expansion of the concrete structure.

Leveling concrete

Flat fiberboard/plywood strips are placed across the platform. Material thickness – up to 3 mm. When the concrete mixture begins to set, the material is removed. It leaves smooth cracks.

Pouring procedure

Buy cement M400. The mixture is created by adding parts to it: 2.5 sand, 4.2 crushed stone. This is how it is possible to obtain M200 concrete. If M500 cement is used, 3.2 sand and 4.9 crushed stone should be added to it.

Initially, the components should be mixed dry, then water is slowly added until the mixture is ready to pour. It is sent inside the formwork to fill all existing voids and profiles located inside.

Initially, the height of laying the solution should exceed the level of the beacons by 5 cm.

Concreted area

Before pouring a concrete pad, you need to know that it is completely poured at one time. Stops are made exclusively at expansion joints. If part of the site is flooded during the day, cracks will begin to form when work continues on another day.

Drying, processing of the concrete layer

After pouring the mixture, wait until the surface dries. The process takes place within 1-2 days. Then the inserts installed to obtain thermal seams are removed, and the surface is cleaned of unevenness.

The time for complete hardening of the concrete surface is up to 28 days. Operation of the site begins in 1.5-2 weeks.

Now you know how to properly concrete a yard in a private house. By following simple recommendations, you can do the work yourself, spending a minimum of money on it.

Concrete platform for cars

Before you make a parking lot for a car at your dacha with your own hands, you need to choose the material from which it will be made so that it is durable and strong.

Common materials and their advantages:

concrete is a durable material, but the most complex option, a monolithic base ensures high reliability of parking for a very long time;
tiling is a long and labor-intensive process, but the platform is durable and will last as long as possible, has an aesthetic appearance, grass can grow in the seams over time; A platform for a car made of tiles
eco-textiles are aesthetically pleasing, but over time, wheel ruts appear; they are easy to install; grass requires periodic watering;
lawn - the area is sprinkled with grass seeds and periodically watered with water, the simplest and most inexpensive option, but with frequent and heavy rains a lot of dirt sticks, and wheel marks remain;
gravel/pebbles/crushed stone - a medium fraction of material is needed, easy parking at low cost, not very aesthetically pleasing and not very convenient to move along the embankment, especially in heels.

Most owners of private plots choose tiles mainly because of their beauty and durability. But sometimes the coating begins to “float” if all installation technologies are not followed, and there are also restrictions on the load. When it is necessary to park a very heavy car or there will be several of them, then it is better to equip a concrete base.

Concrete area in front of the garage

Creating a parking lot

Before you begin completing the tasks, you need to clarify how to fill the area under the car with concrete in the yard, and this is done in several steps:

preparatory work on the site;
arrangement of the bottom of the future site, formwork;
subsequent reinforcement;
preparing the solution and pouring it.

To build a parking lot, you need to know the weight of the car. This will allow you to select the correct grade of concrete strength for the corresponding loads. It is best to use grade 500 cement (with frost-resistant additives) and river sand.

Preparatory work

This stage includes determining the location of the parking lot, measurements and all necessary calculations. The site must be accessible for free movement of the vehicle. The dimensions of the parking lot depend on the number of cars being parked, their size and weight. In this case, the slab should not be located close to the foundation of any buildings. The boundaries of the site are marked with pegs and rope.

Preparing the soil before concreting

Arrangement

Having figured out how to make a parking lot at your dacha with your own hands, you need to prepare the site itself. Grass and debris are removed, at least 20 centimeters of soil are removed, and a sand cushion is installed:

the bottom is covered with a layer of sand (up to 15 cm), leveled, moistened and compacted;
crushed stone is poured (at least 10 cm), leveled and compacted;
the third layer is optional (but recommended by experts) - agrofibre/geotextile (the material will restrain other layers and will not allow them to creep when pouring concrete and due to its heaviness).

The site itself should have a slight slope; it is necessary to provide a drainage area.

Formwork and reinforcement

After the mixture has dried, the formwork will be dismantled. Fences can be wooden or metal, fastened together by any convenient means. Fixed formwork is used less frequently. To create it, a curb stone is used, which is installed around the perimeter. It will be necessary to prepare the appropriate foundation.

Beacons are placed after the formwork has been installed. They are necessary to control the evenness of pouring the mixture. Beacons can be pins made of metal profiles or similar materials. The distance between beacons is allowed no more than 0.5 meters.

Beacons for formwork

Reinforcement is used to enhance the strength of the future foundation. To do this, before pouring, reinforcement is laid on the previous layers in one or two layers. A lattice is made from rods, the diameter of which should be 8-10 millimeters; it is advisable to tie the rods themselves at the joints. It is strictly forbidden to use welding, since the mesh will be very rigid.

Mortar and pouring

Sometimes crushed stone is not added to the mixture. Then the mass must be of such density that it can penetrate between the stones in the prepared cushion.

Pouring is carried out at a time, the amount of concrete should be enough for a base layer of 20-25 centimeters. For parking, the standard mixture is made from the following components: 2/1/3 crushed stone/cement/sand. There should be enough water to create a thick solution.

Hardening occurs within two days; in order to release air from the mass, the base is pierced in several places. Grooves can be left to prevent concrete deformation due to temperature changes.

Experts recommend covering the structure itself with film and moisturizing it 3-5 times a day. This allows the concrete to dry faster and set better. The procedure is repeated for a week. The concrete hardens completely and gains brand strength within a month. Only then can it be used for its intended purpose.

Concreted yard area

Traduction - lock for electroslag welding of a circumferential weld - -

201 torch weld English-Russian big polytechnic dictionary > torch weld
202 upset weld English-Russian big polytechnic dictionary > upset weld
203 Schrittlänge f length w. weld section (for intermittent welding) Neue große deutsch-russische Wörterbuch Polytechnic > Schrittlänge
204 Schweißschritt m size f. pitch (for spot welding); sequence g. applying welding seams; sequence g. suturing; pitch m. (for spot welding) Neue große deutsch-russische Wörterbuch Polytechnic > Schweißschritt
205 Einbrandüberlappung penetration of the root layer of the weld during double-sided welding Neue Deutsch-Russische Wörterbuch > Einbrandüberlappung
206 Kaltschweißstelle Neue Deutsch-Russische Wörterbuch > Kaltschweißstelle
207 Nahtüberdeckung overlap of the seam at the root during double-sided welding Neue Deutsch-Russische Wörterbuch > Nahtüberdeckung
208 test welding Russian-English scientific dictionary > test welding
209 welding strength Russian-English scientific dictionary > welding strength
210 weld The English-Russian dictionary general scientific > weld
211 back-weld seam back-weld seam A smaller part of a double-sided seam, made in advance to prevent burn-through during subsequent welding or applied last at the root of the seam. [GOST 2601-84] [Terminological dictionary for construction in 12 languages (VNIIIS Gosstroy USSR)]

FR

cordon support
cordon a l'envers
soudure de reprise

Russian-German dictionary of normative and technical terminology > welding seam

212 cordon support

French-Russian dictionary of normative and technical terminology > cordon support

213 cordon a l'envers

French-Russian dictionary of normative and technical terminology > cordon à l'envers

214 soudure de reprise

215 Gegennaht

German-Russian dictionary of normative and technical terminology > Gegennaht

216 Kappnaht

German-Russian dictionary of normative and technical terminology > Kappnaht

217 back weld

Russian-English dictionary of normative and technical terminology > welding seam

218 lap seam welding

Russian-English dictionary of normative and technical terminology > lap seam welding

219 back weld

Russian-French dictionary of normative and technical terminology > welding seam

Source: https://translate.fracademic.com/%D0%B7%D0%B0%D0%BC%D0%BE%D0%BA%20%D0%BF%D1%80%D0%B8%20%D1 %8D%D0%BB%D0%B5%D0%BA%D1%82%D1%80%D0%BE%D1%88%D0%BB%D0%B0%D0%BA%D0%BE%D0%B2 %D0%BE%D0%B9%20%D1%81%D0%B2%D0%B0%D1%80%D0%BA%D0%B5%20%D0%BA%D0%BE%D0%BB%D1 %8C%D1%86%D0%B5%D0%B2%D0%BE%D0%B3%D0%BE%20%D1%88%D0%B2%D0%B0/xx/xx/11/

Modern and classic welding technologies

Welding is one of the most important crafts for humans. With the help of welding technologies, we manage to create truly amazing things: from the simplest household appliances to space rockets. In this article we will tell you how welding occurs, what types of welding exist and their brief characteristics.

general information

What is welding? What are the basics of welding? Many beginning craftsmen ask these questions. At its core, welding is the process of joining different metals. A connection (also called a seam) is formed at the interatomic level using heat or mechanical deformation.

The theory of metal welding is very extensive and it is impossible to describe all the nuances within one article. Just as it is impossible to describe all the methods of welding metals, since at the moment there are about a hundred methods. But we will try to briefly classify welding methods so that beginners do not get confused.

So, at the moment, thermal, thermomechanical and completely mechanical welding of parts made of metal or other materials (for example, plastic or glass) is possible. When choosing a welding method, every nuance is taken into account: the thickness of the parts, their composition, working conditions, etc. The metal welding technology depends on this.

Thermal welding is the process of joining parts using only high temperatures. The metal melts and a reliable welded joint is formed. Thermal methods include, for example, arc and gas welding (we will talk about them later).

Thermo-mechanical welding is the process of joining parts using high temperatures and mechanical influence, such as pressure. Resistance welding belongs to this type. The part does not heat up as much as in the case of conventional thermal welding, and mechanical load is used to form the seam, rather than melting the metal itself.

Mechanical welding is the process of joining parts without the use of high temperatures and generally thermal energy. The key element here is mechanical action. This type includes cold welding, ultrasonic welding or friction joining of parts.

There is also a classification of welding methods according to technical characteristics. Using this classification, we can quite briefly describe all available types of welding. They are divided into:

Welding in a protective environment (for protection, flux, inert gas, active gas, vacuum can be used, protection can be combined and consist of several materials at once).
Intermittent and continuous welding.
Welding: manual, mechanized, semi-automatic, automatic, robotic.

If you have never encountered welding before and everything listed above seems confusing and incomprehensible, then don’t worry. Next, we will tell you what the most popular welding methods are used in home and industrial settings.

You will be given a description of the main types of welding and some features that need to be taken into account. By the way, we have devoted separate articles to many types of welding, which you can read by opening the “Types and Methods of Welding” section on our website.

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Manual arc welding using non-consumable electrodes

The method of manual arc welding of different metals using non-consumable electrodes is one of the most popular methods among both home craftsmen and professionals. Manual arc welding is generally one of the oldest welding methods. Thanks to a large selection of welding machines for arc welding, this method has become available to a wide range of welders.

An electrode is a rod that acts as a current conductor. It can be made of various materials and have a special coating.

The technology of arc welding with a non-consumable electrode is extremely simple: the parts are adjusted to each other, then the electrode is tapped or struck on the surface of the metal, igniting the welding arc. Welding inverters are used as the main equipment.

For welding with an inverter, non-consumable electrodes made of coal, tungsten or graphite are chosen. During welding, the electrode heats up to a high temperature, melting the metal and forming a weld pool in which the seam is formed. This method is used for welding non-ferrous metals.

Manual arc welding using consumable electrodes

Types of metal fusion welding do not end with the use of non-consumable rods. You can also use consumable electrodes for work. The technology for welding metal using consumable rods is the same as when working with non-consumable materials.

The only difference is in the composition of the electrode itself: melting rods are usually made of low-melting metals. Such rods are also suitable for welding with an inverter at home. Here the seam is formed not only by the molten metal of the part, but also by the molten electrode.

Arc welding using shielding gas

The method of arc welding of different metals using shielding gas is performed using consumable and non-consumable electrodes. The welding technology is the same as with classic manual arc welding. But here, for additional protection of the weld pool, a special shielding gas supplied in cylinders is supplied to the welding zone.

The fact is that the weld pool is easily susceptible to the negative influence of oxygen and under its influence the seam can oxidize and turn out to be of poor quality. Gas helps to avoid these problems. When it is supplied to the welding zone, a dense gas cloud is formed, which prevents oxygen from penetrating into the weld pool.

Automatic and semi-automatic welding using flux or gas

Automatic and semi-automatic welding using flux or gas is a more advanced method of joining metals. Here, some of the work is mechanized, for example, feeding the electrode into the welding zone. This means that the welder feeds the rod not with his hands, but with the help of a special mechanism.

Automatic welding involves mechanized feeding and further movement of the electrode, while semi-automatic welding implies only mechanized feeding. The welder carries out further movement of the electrode manually.

Here, protecting the weld pool from oxygen is simply mandatory, so gas is used (by analogy with arc welding using gases) or a special flux. Flux can be liquid, paste or crystalline. Using flux, you can significantly improve the quality of the seam.

Other methods of joining metals

In addition to traditional welding methods, modern industry uses methods that allow joining unique metals. Often such metals have pronounced chemical or refractory properties, which is why conventional welding methods are not suitable for joining them. Of course, such metals are not used in home welding, but they are widely used to create critical parts in large-scale production.

We will talk about the types of fusion welding, when the essence of welding is to supply a large amount of heat to a small welding area. These methods include laser welding and plasma welding.

Laser welding of metals is performed using automatic and semi-automatic equipment. This welding process can be completely robotic and does not require human presence.

Here the part heats up and then melts under the influence of heat emanating from a laser beam and directed to a specific point.

The heat is concentrated strictly at one point, allowing you to weld very small parts less than one millimeter in size. Also, using a prism, the laser can be split and directed in different directions to weld several parts at once.

Plasma welding of metals is performed using an ionized gas called plasma. The gas is jetted into the welding zone, forming plasma. It works in conjunction with a tungsten electrode and the gas is heated by an electric arc.

The ionized gas itself has the property of a current conductor, therefore, in the case of plasma welding, plasma is the key element in the working process. Plasma also actively protects the weld pool from the negative effects of oxygen. This welding method is used when working with metals up to 9 millimeters thick.

Welding process

It is not enough to know welding methods; you also need to understand what documents are required for welding and what stages the welding process consists of. Of course, this is only true for professional welders performing work in a workshop or production environment. You don’t need this if you are going to weld a fence at your dacha, but additional knowledge won’t hurt either.

So, here is our brief description of the welding process:

Drawing development
Drawing up a technological map
Preparation of the welder's workplace and metal preparation
Direct welding
Metal cleaning
Quality control

The technical process itself is a complete description of the welding stages. The technical process is developed after the drawings of the future metal structure are ready. The drawing is made based on the rules (GOST, for example), while the quality of the future design and reasonable savings are put at the forefront.

The technological process of welding is drawn up on forms specially designed for this purpose. The standard form for describing a technical process is called a “technological map”. The technological map describes all stages of production. If the production is serial or large-scale, then the presentation can be quite detailed, with a description of every nuance.

The flow chart includes the type of metal from which the parts are made, the metal welding methods used to connect these parts, the welding or other equipment used for these purposes, the types of filler materials, electrodes, gases or fluxes used in the work. The sequence of formation of seams, their sizes and other characteristics are also indicated.

The technological map also indicates the brand of electrodes, their diameter, their feed speed, welding speed, the number of layers at the seam, the recommended settings of the welding machine (polarity parameter and welding current value), and the brand of flux.

Before welding, the parts are carefully prepared, cleaning them from corrosion, dirt and oil. The metal surface is degreased using a solvent. If a part has significant visible defects (for example, cracks), then it is not allowed for welding.

After welding, the weld seams will be inspected. We have devoted a separate article to this topic, but here we will briefly talk about the main control methods. First of all, visual inspection is used, when the welder himself can determine the presence of defects in the welding joint. Specialists carry out additional monitoring using special devices (this can be magnetic testing, radiation or ultrasonic testing).

Of course, not all defects are considered bad. For each welding job, a list of defects is compiled that are acceptable and will not greatly affect the quality of the finished product. The controller can be a welder or a separate specialist. His name must be indicated in the documents; he is the responsible person at the control stage.

Instead of a conclusion

In this article we covered the most basic things. Of course, we will not be able to list and describe all types of welding work in this one article, but on our website you can find materials where we tell everything about welding and explain the basics of welding various metals.

For any master, the theory of welding processes is of great importance, but without practice it does not work. So don’t waste time and after reading the articles, apply your knowledge in practice. We wish you good luck in your work!

Source: https://svarkaed.ru/svarka/poleznaya-informatsiya/sovremennye-i-klassicheskie-svarochnye-tehnologii.html

Transformer no-load mode

One of the most used electrical devices is the transformer. This equipment is used to change the magnitude of electrical voltage. Let's consider the features of the transformer no-load mode, taking into account the rules for determining characteristics for various types of devices.

The transformer consists of primary and secondary windings located on the core. When voltage is applied to the input coil, a magnetic field is formed, inducing a current in the output winding. The difference in characteristics is achieved due to the different number of turns in the input and output coils.

Transformer operating principle

What is idle mode

The idle mode is understood as the state of the device in which, when an alternating current is supplied to the input coil, the output coil is in an open state. This situation is typical for a unit connected to the mains, provided that the load to the output circuit has not yet been turned on.

Short circuit mode

How is the idle test performed?

When conducting an idle test, it becomes possible to determine the following characteristics of the unit:

transformation ratio;
power loss in steel;
parameters of the magnetizing branch in the equivalent circuit.

For the experiment, a rated load is applied to the device.

When conducting an idle test and calculating characteristics based on this technique, it is necessary to take into account the type of device.

In this state, the transformer has zero useful power due to the absence of electric current at the output coil. The applied load is converted into heat loss on the input coil I02×r1 and magnetic core loss Pm. Due to the insignificance of heat losses at the input, they are not taken into account in most cases. Therefore, the total value of no-load losses is determined by the magnetic component.

Also read: Purpose of voltage indicators

The following are the features of calculating characteristics for various types of transformers.

For single phase transformer

The no-load test for a single-phase transformer is carried out with the connection:

voltmeters on the primary and secondary coils;
wattmeter on the primary winding;
ammeter at the input.

The devices are connected according to the following scheme:

To determine the no-load current Iо, use an ammeter reading. It is compared with the rated current value using the following formula, resulting in a percentage:

Iо% = I0×100/I10.

To determine the transformation ratio k, determine the value of the rated voltage U1н according to the readings of the voltmeter V1 connected to the input. Then, using the voltmeter V2 at the output, the value of the rated voltage U2O is taken.

The coefficient is calculated using the formula:

K = w1/w2 = U1н/ U2О.

The amount of loss is the sum of the electrical and magnetic components:

P0 = I02×r1 + I02×r0.

But, if we neglect electrical losses, the first part of the sum can be excluded from the formula. However, an insignificant amount of electrical losses is typical only for low-power equipment. Therefore, when calculating the characteristics of powerful units, this part of the formula should be taken into account.

No-load losses for transformers with a power of 30-2500 kVA

For three-phase transformer

Three-phase units are tested according to a similar scheme. But the voltage is supplied separately for each phase, with the appropriate installation of voltmeters. You will need 6 units of them. You can conduct an experiment with one device, connecting it to the required points one by one.

When the rated voltage of the winding electric current is more than 6 kV, 380 V is supplied for testing. The high-voltage mode for conducting the experiment will not allow achieving the necessary accuracy for determining the indicators. In addition to accuracy, the low-voltage mode ensures safety.

The following scheme applies:

The operation of the device in idle mode is determined by its magnetic system. If we are talking about a type of device similar to a single-phase transformer or an armored rod system, the closure of the third harmonic component for each phase will occur separately, with a value increasing to 20 percent of the active magnetic flux.

For welding transformer

For welding transformers, idling is one of the modes of their constant use in operation. During welding in operating mode, the second winding is short-circuited between the electrode and the metal of the part. As a result, the edges melt and a permanent connection is formed.

After finishing work, the electrical circuit is broken and the unit goes into idle mode. If the secondary circuit is open, the voltage in it corresponds to the EMF value. This component of the power flow is separated from the main one and is closed through the air.

To avoid danger to humans when the machine is idling, the voltage value should not exceed 46 V. Considering that in some models the value of these characteristics exceeds the specified value, reaching 70 V, the welding unit is equipped with a built-in performance limiter for idle mode.

The blocking is activated within a time not exceeding 1 second from the moment the operating mode is interrupted. An additional protective measure is a grounding device for the welding unit housing.

Measures to reduce no-load current

The current when the transformer is in idle mode occurs due to the design features of the core. A ferromagnetic material exposed to an alternating current electric field is characterized by the induction of eddy inductive Foucault currents, which cause heating of the element.

To reduce eddy currents, the core is not made as a single piece, but is assembled from a package of thin plates. The plates are insulated from each other. An additional measure is to change the properties of the material itself, which makes it possible to increase the threshold of magnetic saturation.