home Credit Gases for gas welding and metal cutting. Gas mixtures for welding

Gases for gas welding and metal cutting. Gas mixtures for welding

In our time to conduct repair work In the field of shipbuilding, automotive industry, and construction, gas welding is widely used. During the gas welding process, the base and filler materials melt in an open torch. During gas welding, the metal is gradually heated. Thanks to this, it has found wide application in welding non-ferrous metals, cast iron and steel.

The flame in the burner is maintained by the supply of combustible gases contained in the cylinder: propane, diacine, hydrogen, methane, acetylene, oxygen and others. When carrying out gas welding, it is necessary to carefully observe safety precautions. There should be no flammable objects within a meter radius near you. It would be a good idea to stock up on a container of water.

Gas welding is preferred because of its simplicity and mobility.

The gas welding process is simple, so you can easily master the heating and welding technique. The main thing for a welder is to master the work using a torch and rod. This will ensure high-quality performance of gas welding work.

Those who carry out gas welding work for the first time, as a rule, have many questions related to technology, methodology and the gas welding process itself. A novice welder tries to choose the most optimal technique for himself, depending on the type of materials used in the welding process. To skillfully approach the welding process, you can use tips that will certainly help you.

Instructions for working with gas welding

First you need to select your equipment. Do not forget that during the welding process you will have to work with a gas cylinder. Therefore, it is necessary to become thoroughly familiar with the safety regulations.

Depending on the type of surface that needs to be welded, a specific welding technique is selected.

Acetylene is the main component in the gas welding process. For welding, dissolved (in a cylinder) or gaseous acetylene is used. Acetylene cylinders are used for gas welding work of any complexity, both at the household level and when carrying out high-tech welding. Acetylene can be called one of the highest quality flame sources. This is due to the fact that there is no need to use any oxidizing agent.

First, it is necessary to prepare a gas cylinder with which oxygen-acetylene gas welding will be performed, taking into account hard-to-reach places. You will also need a torch with four tips. To practice your welding skills, use the smallest tip size first. Try to ensure that pressure is maintained in all hoses of the device. The pressure for oxygen and acetylene must be different. It is necessary to ensure that the pressure indicators remain at the level: for oxygen no more than 0.3 MPa, for acetylene - no less than 1 kPa.

During the gas welding process, you can use an oxygen hose, which belongs to class III. It will ensure the supply of oxygen to the gas cylinder with optimal pressure, which is provided by gas welding technology for small connections.

To ensure that the seam when welding surfaces is of high quality and beautiful, use G3. Its use requires skill and increased safety requirements. In any case, you must wear protective clothing - these are thick pants and a jacket. The head must be protected by a hat. The face must be completely covered using a special mask.

You can fully master the art of gas welding only after studying and completing special courses. This will help you choose the right torch for gas welding. When performing gas welding work, it is necessary to correctly position the device relative to the surfaces being welded, while maintaining the optimal angle. This is necessary to form a beautiful and even seam. Upon completion of gas welding work, to give the product an aesthetic appearance, you need to carefully clean off the scale.

Gas welding, how to cook with gas welding, gas welding for beginners, How to work with gas welding, how to cook with gas welding correctly

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Gas welding - advantages and disadvantages

Welding first appeared in ancient Egypt. People learned to weld iron simultaneously with other methods of processing various metals. Of course, the quality of welding of that time is very different from the quality of our days, but nevertheless, many palaces, temples and other structures are still based on the first structures made by welding.

No matter how paradoxical it may sound, man first discovered and improved electric welding. Later, namely, in 1903, a gas welding apparatus was invented in France. The welding machine used oxygen and acetylene. The design of the invented gas apparatus is, in principle, still used today, but it has been constantly improved. Equipment, oxygen cylinders, gearboxes and other materials were improved and changed. Like electric arc and laser welding, gas welding has its own peculiarities in the technology for making seams. They should always be taken into account when choosing a particular type of work. Things like the balance of minimizing welding costs and weld quality are very important.

Let's consider the advantages of gas welding

Gas welding does not require expensive complex equipment or additional energy sources. In this way, you can weld metal even in an open open field or deep forest. In the third decade of the 20th century, all oil pipelines were welded using gas welding. These features allow welding work to be carried out in any premises, buildings and regions.

It is possible to weld metals with a wide range of melting temperatures by widely varying the power of the gas welding flame. Materials such as brass, lead and cast iron are best welded using gas welding. If you choose the right filler wire brand and flame power, you can get high-quality seams. Even the most critical areas trust gas-acetylene welding. Welded surfaces heat up and cool down very slowly. You can easily change the flame temperature. When the angle of inclination to the surface being welded changes, the flame temperature also changes. The quality and strength of the seams is usually higher than when using electric arc welding. Gas welding can be used to cut, harden and weld various metals.

Disadvantages of gas welding

Gas welding has a large heating zone. If thermally unstable elements are located near the welded area, they will be damaged. Welding metal with a thickness of more than 5 millimeters is unprofitable. The greater the thickness, the more the welding performance decreases. In such cases, it is better to use electric arc welding.

In gas welding, very dangerous substances are used, such as hydrogen, acetylene, which when combined with oxygen produce an explosive mixture. Gas cylinders should be kept as far away from organic substances as possible. Otherwise, failure to comply with safety precautions will lead to an explosion and fire. Gas welding cannot be mechanized. It is not possible to alloy directional metal. Using gas welding, it is not recommended to weld high-carbon metals. Welded surfaces heat up and cool down very slowly.

A special feature of the technology is that during gas welding the surface slowly heats up and cools down. The advantage of slow heating/cooling is that many alloys and metals require gradual heating conditions. Non-ferrous metals can be welded very well using gas welding. Gas welding also has several features. Three types of oxygen are used. As a rule, the purer the oxygen, the faster the cutting process and the better the quality of the edge. Gas welding has a place in the construction field. Will be used for a very long time various types production.

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Everything you need to know about gas welding - Welder's Handbook

Gas welding is a special type of welding, since its operating principle is based on the method of melting metal. In order to carry out gas welding, it is possible to use a variety of flammable and gases. Therefore, welding can be, for example, oxygen-hydrogen, gasoline-oxygen, and so on. Also, there is acetylene-oxygen gas welding, and other types that are used both in mass quantities and in single applications. The main, significant technological difference between gas welding and any other type of welding is the smooth and quieter, slower heating of the metal.

This is the main difference - the use of a gas flame as a welding method and a welding arc. This application has both its advantages and disadvantages. Thus, gas welding is used in a number of cases:

1). For steels with a thickness of 0.2-5 mm;

2). For welding non-ferrous metals;

3). For any metals that require smooth heating and slow decay during the welding process;

4). For metals that require preheating (again, for non-ferrous metals, and for cast iron);

5). For hard soldering processes;

6). For surfacing and surfacing work.

Gas welding has obvious advantages, such as comparative simplicity and portability, which allows the use of such welding for many types of work. Slow heating of the metal using a gas flame, as a rule, reduces the degree of productivity of gas welding, with thickening of the metal, and it turns out that with a thickness of 8-10 mm, gas welding becomes economically unprofitable, although it is still technically suitable for work with metals, thickness 30-40 mm. Also, the fact that the gas flame heats up the welding area for a long time becomes the reason that the near-weld area may deform or lose its mechanical properties Therefore, prolonged heating has both its pros and cons.

The gas burner is regulated when the flame is burning normally. So, it is adjusted to the required metal thickness, and only then the welding flame is activated, after which work can begin. Therefore, one of the most basic tasks of a welder is to determine required level operation of the burner, to work with one or another section of metal. Also, during work, other parameters are taken into account - pressure, distance from the product to the burner, flame angle, and so on, which together results in the use of gas welding.

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Gas welding is relatively simple and does not require complex, expensive equipment or a source of electricity.

The disadvantage of gas welding is the lower heating rate of the metal compared to arc welding and a larger zone of thermal influence on the metal. When gas welding, the heat concentration is less, and the warping of the parts being welded is greater.

Due to the relatively slow heating of the metal by the flame and the low heat concentration, the productivity of gas welding decreases with increasing thickness of the metal being welded. For example, with a steel thickness of 1 mm, the gas welding speed is about 10 m/h, with a thickness of 10 mm - only 2 m/h. Therefore, gas welding of steel with a thickness of over 6 mm is less productive than arc welding.

The cost of acetylene and oxygen is higher than the cost of electricity, so gas welding is more expensive than electric welding. Disadvantages of gas welding also include explosion and fire hazards if the rules for handling calcium carbide, flammable gases and liquids, oxygen, cylinders with compressed gases and acetylene generators are violated. Gas welding is used for next works: production and repair of steel products with a thickness of 1-3 mm; welding of vessels and small tanks, welding of cracks, welding of patches, etc.; repairs cast products made of cast iron, bronze, silumin; welding joints of pipes of small and medium diameters; manufacturing products from aluminum and its alloys, copper, brass and lead; production of structural units from thin-walled pipes; surfacing of brass on parts made of steel and cast iron; joining ductile and high-strength cast iron using filler rods made of brass and bronze, low-temperature welding of cast iron.

Gas welding can be used to join almost all metals used in technology. Cast iron, copper, brass, and lead are easier to gas weld than arc welding.

GAS WELDING TECHNIQUE

Gas welding can be used to perform bottom, horizontal, vertical and ceiling seams. Ceiling seams are the most difficult to make, since in this case the welder must maintain and distribute liquid metal along the seam using the pressure of the flame gases. Most often gas welding is used to make butt joints, less often corner and end joints. It is not recommended to make lap and T-joints using gas welding, since they require intense heating of the metal and are accompanied by increased warping of the product.

Beaded joints of thin metal are welded without filler wire. Intermittent and continuous seams are used, as well as single-layer and multi-layer seams. Before welding, the edges are thoroughly cleaned of traces of oil, paint, rust, scale, moisture and other contaminants.

In table Figure 10 shows edge preparation for gas welding carbon steels butt seams.

MOVEMENT OF THE TORCH DURING WELDING

The burner flame is directed at the metal being welded so that the edges of the metal are in the reduction zone, at a distance of 2-6 mm from the end of the core. It is impossible to touch the molten metal with the end of the core, as this will cause carburization of the metal of the bath. The end of the filler wire must also be in the reduction zone or immersed in the molten metal pool. In the place where the end of the flame core is directed, the liquid metal is slightly inflated to the sides by gas pressure, forming a depression in the weld pool.

The rate of heating of metal during gas welding can be adjusted by changing the angle of inclination of the mouthpiece to the metal surface. The larger this angle, the more heat is transferred from the flame to the metal and the faster it will heat up. When welding thick or good heat-conducting metal (for example, red copper), the angle of inclination of the nozzle a is taken greater than when welding thin or low thermal conductivity. In Fig. 86, and shows the angles of inclination of the mouthpiece recommended for left-handed (see § 4 of this chapter) welding of steel of various thicknesses.

In Fig. 86, b shows ways to move the mouthpiece along the seam. The main thing is to move the mouthpiece along the seam. Transverse and circular movements are auxiliary and serve to regulate the rate of heating and melting of the edges, and also contribute to the formation the desired shape weld seam.

Method 4 (see Fig. 86, b) is used when welding thin metal, methods 2 and 3 - when welding metal of medium thickness. During welding, you must strive to ensure that the metal of the pool is always protected from the surrounding air by the gases of the reduction zone of the flame. Therefore, method 1, in which the flame is periodically drawn to the side, is not recommended, since it may oxidize the metal with atmospheric oxygen.

BASIC GAS WELDING METHODS

Left welding (Fig. 87, a). This method is the most common. It is used when welding thin and low-melting metals. The torch is moved from right to left, and the filler wire is led in front of the flame, which is directed to the unwelded section of the seam. In Fig. 87, and below shows a diagram of the movement of the mouthpiece and wire during the left-hand welding method. The flame power for left-hand welding is taken from 100 to 130 dm 3 acetylene per hour per 1 mm of metal (steel) thickness.

Right welding (Fig. 87, b). The torch is driven from left to right, the filler wire is moved after the torch. The flame is directed to the end of the wire and the welded area of the seam. Transverse oscillatory movements are not performed as often as during left-hand welding. The mouthpiece makes slight transverse vibrations; When welding metal with a thickness of less than 8 mm, the nozzle is moved along the axis of the seam without transverse movements. The end of the wire is kept immersed in the weld pool and the liquid metal is mixed with it, which makes it easier to remove oxides and slags. The heat of the flame is dissipated to a lesser extent and is better utilized than in left-hand welding. Therefore, during right-hand welding, the opening angle of the seam is made not 90°, but 60-70°, which reduces the amount of deposited metal, wire consumption and warping of the product due to shrinkage of the weld metal.

It is advisable to use right-hand welding to connect metal with a thickness of more than 3 mm, as well as metal with high thermal conductivity with grooved edges, such as red copper. The quality of the seam in right-hand welding is higher than in left-hand welding because the molten metal is better protected by the flame, which simultaneously anneals the deposited metal and slows down its cooling. Due to the better use of heat, right-hand welding of metal of large thicknesses is more economical and more productive than left-hand welding - the speed of right-hand welding is 10-20% higher, and gas savings are 10-15%.

Right-hand welding connects steel up to 6 mm thick without bevel of edges, with full penetration, without back-welding with reverse side. The flame power for right-hand welding is taken from 120 to 150 dm 3 acetylene per hour per 1 mm of metal (steel) thickness. The mouthpiece must be inclined to the metal being welded at an angle of at least 40°.

When right-hand welding, it is recommended to use filler wire with a diameter equal to half the thickness of the metal being welded. When left welding, use a wire with a diameter 1 mm larger than when welding right. Wire with a diameter of more than 6-8 mm is not used for gas welding.

Welding with a through bead (Fig. 88). The sheets are installed vertically with a gap equal to half the thickness of the sheet. The burner flame melts the edges, forming a round hole, the lower part of which is smelted with filler metal over the entire thickness of the metal being welded. Then the flame is moved higher, melting the upper edge of the hole and applying the next layer of metal to bottom side holes, and so on until the entire seam is welded. The seam is obtained in the form of a through bead connecting the sheets to be welded. The weld metal is dense, without pores, cavities and slag inclusions.

Welding with baths. This method is used to weld butt and corner joints of metal of small thickness (less than 3 mm) with filler wire. When a pool with a diameter of 4-5 mm is formed on the seam, the welder inserts the end of the wire into it and, melting a small amount of it, moves the end of the wire into the dark, reducing part of the flame. At the same time, he makes a circular motion with the mouthpiece, moving it to the next section of the seam. The new bath should overlap the previous one by 1/3 of the diameter. To avoid oxidation, the end of the wire must be kept in the reducing zone of the flame, and the flame core should not be immersed in the bath to avoid carburization of the weld metal. Welded in this way (with lightweight seams) thin sheets and pipes made of low-carbon and low alloy steel produce compounds of excellent quality.

Multilayer gas welding. This welding method has a number of advantages compared to single-layer welding: a smaller metal heating zone is provided; annealing of underlying layers is achieved when surfacing subsequent layers; it is possible to forge each layer of the seam before applying the next one. All this improves the quality of the weld metal. However, multilayer welding is less productive and requires more gas consumption than single-layer welding, so it is used only in the manufacture of critical products. Welding is carried out in short sections. When applying layers, you need to ensure that the joints of the seams in different layers do not coincide. Before applying a new layer, use a wire brush to thoroughly clean the surface of the previous one from scale and slag.

Oxidizing flame welding. Low carbon steels are welded using this method. Welding is carried out with an oxidizing flame having the composition

To deoxidize the iron oxides formed in the weld pool, wires of the Sv-12GS, Sv-08G and Sv-08G2S grades in accordance with GOST 2246-60 are used, containing increased amounts of manganese and silicon, which are deoxidizers. This method increases productivity by 10-15%.

Welding with propane - butane-oxygen flame. Welding is carried out with an increased oxygen content in the mixture

in order to increase the flame temperature and increase the penetration and fluidity of the bath. For deoxidation of weld metal, wires Sv-12GS, Sv-08G, Sv-08G2S, as well as wire Sv-15GYU (0.5-0.8% aluminum and 1 - 1.4% manganese) according to GOST are used.

Research by A. I. Shashkov, Yu. I. Nekrasov and S. S. Vaksman established the possibility of using in this case conventional low-carbon filler wire Sv-08 with a deoxidizing coating containing 50% ferromanganese and 50% ferrosilicon diluted on liquid glass. The weight of the coating (excluding the weight of liquid glass) is 2.8-3.5% of the weight of the wire. Coating thickness: 0.4-0.6 mm when using wire with a diameter of 3 mm and 0.5-0.8 mm when using a wire with a diameter of 4 mm. Propane consumption is 60-80 l/h per 1 mm of steel thickness, b = 3.5, the angle of inclination of the rod to the metal plane is 30-45°, the cutting angle of the edges is 90°, the distance from the core to the rod is 1.5-2 mm, to metal 6-8 mm. This method can weld steel up to 12 mm thick. The best results were obtained when welding steel with a thickness of 3-4 mm. Wire Sv-08 with the specified coating is a full-fledged substitute for more scarce grades of wire with manganese and silicon when welding with propane-butane.

Features of welding various seams. Horizontal seams are welded in the right way (Fig. 89, a). Sometimes welding is done from right to left, holding the end of the wire at the top and the mouthpiece at the bottom of the bath. The weld pool is positioned at a certain angle to the axis of the seam. This makes it easier to form a seam, and keeps the bath metal from dripping.

Vertical and inclined seams are welded from bottom to top using the left method (Fig. 89, b). When the metal thickness is more than 5 mm, the seam is welded with a double bead.

When welding ceiling seams (Fig. 89, c), the edges are heated until melting (fogging) begins, and at this moment a filler wire is introduced into the bath, the end of which is quickly melted. The metal of the bath is kept from flowing down by a rod and the pressure of the flame gases, which reaches 100-120 gf/cm2. The rod is held at a slight angle to the metal being welded. Welding is carried out in the right way. It is recommended to use multi-layer seams welded in several passes.

Welding of metal less than 3 mm thick with flanged edges without filler metal is carried out using spiral (Fig. 89, d) or zigzag (Fig. 89, e) movements of the nozzle.

Administration Overall rating of the article: Published: 2011.05.31

Having appeared on the market, inverter welding machines have replaced other equipment used for joining metal parts and assemblies. But any experienced welder will say that autogenous welding is first class in school curriculum a welder, without which it is impossible to master the technique of welding metals and understand the welding process itself. In addition, it should be noted that this type welding is still often used, and in some cases it simply cannot be avoided.

Autogenous welding includes:

Two cylinders: oxygen and acetylene.
Two reducers, one for each cylinder.
Flame arrestors, one per cylinder.
Set of two hoses: one for oxygen, the second for acetylene.
A burner equipped with nozzles with holes of different diameters.

An oxygen cylinder is a metal container with a wall thickness of 6 mm, a volume of 40 liters, which holds 6000 liters of oxygen under a pressure of 150-200 atmospheres. The cylinder is seamless, which is why it can withstand such high pressure loads. In its upper part there is a valve to which the oxygen reducer is screwed. Basic Requirement safe operation– prevent oil and grease from getting on the valve, especially at the junction with the gearbox. Oxygen quickly reacts with oils, and an oxidation reaction occurs, which leads to an explosion.

The acetylene cylinder has a completely different design. The thing is that compression of acetylene necessarily leads to an explosion. To prevent this from happening, it is necessary to divide this gas into small volumes. And to increase the volume itself, you need to dissolve it in acetone, which absorbs acetylene in large quantities. The absorption proportion is 1 to 360. That is, one liter of acetone absorbs 360 liters of acetylene. The mixture is broken down into small volumes due to the porous structure of the balloon filler. This material contains acetone. By the way, its quantity is equal to 16 liters, respectively, the quantity of acetylene at a pressure of 15 atmospheres will be equal to 6000 liters.

The porous material is a symbiosis of asbestos, charcoal, kieselguhr and astringent fillers. The wall thickness of the acetylene cylinder is 4-5 mm.

As in the case of an oxygen cylinder, the acetylene cylinder also has a valve, to which its own special reducer is attached. It should be noted that oils and fats in this container are not dangerous. The only thing that needs to be taken into account is to keep the acetylene cylinder in a vertical position when performing autogen welding.

As for the reducers (acetylene and oxygen), their task is to reduce the gas pressure to the required values. Both devices have almost the same design, which is based on a spring-loaded valve. They also have two pressure gauges installed, one of which shows the pressure inside the cylinder, the second the gas pressure after the reducer, that is, on the burner.

The pressure indicators after the reducer should be as follows:

Oxygen – 2.5-3.0 atm.
Acetylene - 0.3-0.7 atm.

These indicators are not absolute, because gas welding is used to connect metals of different thicknesses. And the thicker the workpiece, the greater the gas pressure should be on the burner. In addition, metal cutting with an autogenous machine is also carried out using increased rates pressure.

A flame arrestor or check valve is a device that protects against blowback. They are installed immediately after the gearboxes, and the hoses themselves are connected to it. What does reverse strike mean?

There are situations when acetylene begins to rise up the oxygen hose, reaching its reducer. If two gases mix in this place, then this is a guarantee of a big explosion. Flame suppression valves help prevent this. In addition, there are certain actions of the welder himself that ensure the safety of autogenous work. But more on that below.

Now about the hoses. What are the requirements for them?

This rubber products with fabric cord inside.
The color of the oxygen hose is blue, the acetylene hose is red. Changing their places is strictly prohibited.
They are connected to welding equipment devices only with fittings through nipples.
Commonly used hoses have an internal diameter of 9 or 12 mm.
Their minimum length is 8 m, maximum – 20 m.
The hose set is a dual design of acetylene and oxygen.

The burner is the most important element welding equipment where two gases are mixed and where the mixture comes out at supersonic speed. The hoses are connected to the burner using fittings. Higher up the handle there are valves with which the supply of each gas is regulated. In this case, oxygen passes through the injector, in which acetylene is drawn along with it. That is why the pressure of the acetylene reducer is set equal to atmospheric pressure or slightly higher.

Welding technique

Very important point- this is the correct way to ignite the gas mixture and turn it off. The connection is made in this sequence.

First, the oxygen valve on the burner opens.
Then acetylene.
The burner is moved to the side and ignited.
In this case, the flame will have a red tint, it will be long, and it will definitely smoke.
The oxygen supply opens a little more and the acetylene supply decreases. You can visually check the setting; the flame should turn bluish.

The burner is turned off in the reverse order: first the acetylene valve is closed, after 10 seconds the oxygen valve is closed. It is this procedure for shutting off the gas supply that ensures the safe operation of welding equipment. That is, the occurrence of that same reverse strike is prevented.

As for conducting the welding process, it can be carried out from left to right or vice versa. The first option is when the torch moves along the weld seam, and the filler wire moves behind it. The second option is that the wire moves in front of the burner. The first option is preferable because the welding joint is first heated, and then the molten wire metal enters it. In this case, the flame pushes oxygen and nitrogen out of the welding zone, which negatively affect the quality of the final result.

The quality of a weld is not only about technique and correctly selected gas pressure parameters. This is enough big list additional criteria, depending mainly on the thickness of the workpieces being welded. Namely:

thickness of the wire used;
correctly selected burner nozzle diameter;
speed of torch movement along the seam;
wire feed speed into the welding zone;
the percentage of each gas in the feed mixture.

It should be taken into account that the temperature in the welding zone when using an acetylene torch is several times lower than when welding with electrodes. Therefore, autogenous welding should be carried out more slowly. And accordingly, the process itself should be carried out more carefully. Otherwise, defects in the weld seam cannot be avoided. For example, an uncooked layer may form, which welders call cold. Pores, oxide-type inclusions or undercuts may appear. Often there are notches at the very root of the seam.

Safety precautions

Cylinders can only be moved using special transport.
The distance from the cylinders to industrial and residential buildings is at least 10 m.
They can only be stored in metal cabinets with holes; the cabinet must be installed outdoors and always be locked.
Welding is carried out away from explosive and flammable substances.
A fire extinguisher must always be present at the welding site.
During operation, constant checks are carried out to detect gas leaks.

Autogenous technology for welding metals is simpler. With a little experience, you can already cook without looking back at the master. This is why it is believed that it is Primary School for the welder.

Nowadays, gas welding is widely used to carry out repair work in the field of shipbuilding, automotive industry, and construction. During the gas welding process, the base and filler materials melt in an open torch. During gas welding, the metal is gradually heated. Thanks to this, it has found wide application in welding non-ferrous metals, cast iron and steel.

Gas welding is preferred because of its simplicity and mobility.

The gas welding process is simple, so you can easily master the heating and welding technique. The main thing for a welder is to master the work using a torch and rod. This will ensure high-quality performance of gas welding work.

Those who carry out gas welding work for the first time, as a rule, have many questions related to technology, methodology and the gas welding process itself. A novice welder tries to choose the most optimal technique for himself, depending on the type of materials used in the welding process.
To skillfully approach the welding process, you can use tips that will certainly help you.

Instructions for working with gas welding

Depending on the type of surface that needs to be welded, a specific welding technique is selected.

First, it is necessary to prepare a gas cylinder with which oxygen-acetylene gas welding will be performed, taking into account hard-to-reach places.
You will also need a torch with four tips. To practice your welding skills, use the smallest tip size first. Try to ensure that pressure is maintained in all hoses of the device. The pressure for oxygen and acetylene must be different. It is necessary to ensure that the pressure indicators remain at the level: for oxygen no more than 0.3 MPa, for acetylene - no less than 1 kPa.

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gas welding, how to cook with gas welding, gas welding for beginners, How to work with gas welding, how to cook with gas welding correctly

Gas welding is the joining of metals by forming weld pools when metal surfaces are heated with a high-temperature flame, which is formed during the combustion of a mixture of acetylene and oxygen; in this case, oxygen is a catalyst, which leads to instant ignition of acetylene and the formation of a welding jet.

In some cases, acetylene can be replaced with propane-butane, methane, gasoline vapors (jewelry industry and welding precious metals), hydrogen obtained through the electrolysis of distilled water.

Combustible gas together with oxygen is supplied to the welding device and discharged through a calibrated nozzle, after which ignition occurs, the supply is adjusted using valves.

In this case, the flame consists of three components:

core;
recovery;
torch.

The most heat in the core of the flame, but welding is done by the part between the reduction and the core.

In addition, the effect of an open high-temperature flame on the welded surfaces protects the weld pool from interaction with air.

Due to its high ability to cut metals, this type of welding is also used for shaped and high-precision cutting of metal sheets, manufacturing parts and products.

Among the many metal processing technologies, laser cutting stands out for its cost-effectiveness and efficiency. Read about laser cutting metal

Direct welding with an acetylene torch involves heating the welded edges, melting them and joining them;
Surfacing, spraying.

This type of gas welding involves the use of a filler rod made of soft metal, which additionally saturates the weld pool at the melted edges.

The qualitative difference between the two methods lies in the consumption of the gas mixture, time and functionality.

In the first case, greater gas consumption is required, since melting two metal edges requires more temperature than heating a filler rod made of low-melting metals.

Cold welding of linoleum is a very effective and technologically advanced way of fastening linoleum coverings together. More details

Welding using additives is much stronger and looks more aesthetically pleasing, and takes less time for the same reason as less gas consumption.

The scope of application of this type of welding is wide: welding of thin-walled pipes of technological pipelines, welding of technological products and spare parts of machines, surfacing of rods on spare parts and cast iron parts, heating of forged fragments and forging.

Welding consists of the following elements: a cylinder with propane (or any other flammable gas, similar in fluidity properties to inert), a cylinder with oxygen, which is a catalyst for ignition, and gas cutting, which consists of a bronze tube, two regulator valves for propane and oxygen, at the end of the tube there is a calibrated nozzle-nozzle for spraying gas under pressure.

Ignition is carried out with a special silicon piezo lighter.

Pros:

the most important positive criterion is autonomy and the absence of the need for a source of variable or direct current. This fact makes it extremely effective use this type of welding at closed sites, construction sites, remote sites where there is no constant and uninterrupted power source;
adjusting the distance of the welder from the surface of the welding metals and adjusting temperature conditions allows you to avoid burn-throughs, even if thin-sheet metal plates are welded;
the equipment is lightweight and very mobile for movement and transportation;
reliability and quality of the work performed is the main positive characteristic of this type of welding.

low productivity, slow high-precision work that requires;
high temperature, which has a large circumferential range;
Consumables.

Precautions and rules for using a gas burner

Since the gas burner has a high temperature range of circumferential action, it is necessary to remember the following safety rules:

all work must be done in gauntlet gloves, which will protect the welder’s palms from burns;
It is also undesirable to look at the flame core, since temperatures above 1000 degrees and light load negatively affect the cornea of the eye.

Very carefully: it is strictly forbidden to take gas cutting and open an oxygen cylinder with oily hands, as when interacting industrial oil and oxygen, an instantaneous ignition of oxygen and an explosion occurs in the confined space of the cylinder.

Gas cutting and autogen welding has been a standard of quality and functionality for a range of industrial applications for over 60 years.

Convenience and accessibility, the combination of price and quality have brought this type of welding on par with

Independent, without the participation of professionals, but high-quality and fast assembly of metal structures during repair work, soldering seams, as well as cutting various metal products possible with a good home welding machine. ABOUT welding machines read