Cutting large thicknesses
For oxygen cutters of a conventional device, it is possible to consider normal thickness thicknesses to 200-300 mm, as not causing special difficulties and do not require special special cutting techniques. The thicknesses from above these are considered large and require special equipment and special cutting techniques, which meets significant difficulties.
Difficulties in cutting large thicknesses are mainly in the following. Special powerful cutters are required with an increased heating flame and with an increased diameter of the nozzle of cutting oxygen. According to the existing theory, the pressure of cutting oxygen should increase with an increase in the cut thickness. There are empirical formulas for determining the pressure of cutting oxygen depending on the cut. In ordinary cutters with a cylindrical or step-cylindrical nozzle, the pressure of cutting oxygen at the inlet to the cutter changes from 3-4 ati for small thicknesses to 8–9 ati for a thickness of 100 mm, 11-12 ati for 200 mm, 12-14 ati for 300 mm, 20-25 ati for 400-500 mm. The cutting of large thicknesses becomes almost impossible due to the difficulty of using high-pressure oxygen (the need for particularly durable armored hoses and t. P.), in the main way, due to the rapid expansion of the oxygen jet on the exit from the nozzle and significant cooling of oxygen due to the throttle effect. The expansion of the jet is explained by the imperfection of the operation of a cylindrical nozzle, so oxygen in the exit from the nozzle has pressure significantly exceeding atmospheric, and continues to expand in the jet outside the nozzle, which causes an increase in the section of the jet. The drop in oxygen pressure from the input to the atmospheric causes its significant cooling; the higher the input pressure, the stronger the cooling. The expansion of the jet and the cooling of oxygen, which inhibits the cutting process, affects more and more as the input pressure of the cutting oxygen increases, t. e. Increase in metal thickness.
The continuously growing need for cutting more and more large metal thicknesses, respectively, the general growth of industry power, makes us more closely approach the study of the process of oxygen cutting. Such a study in relation to the cutting of large thicknesses from the end of 1948. Engaged in Ing. M. M. The board and author of this book that came to the following basic conclusions. The pressure of oxygen at the entrance to the cutter is determined mainly by the design of the cutter and is not a characteristic value for the cutting process. The main values are the speed, length and section of the jet of oxygen. The speed should be supersonic. The length of the jet depends on its initial section, the design of the nozzle and speed at the output.
The structure of the jet and the distribution of velocities in it are schematically shown in FIG. 234. A stream of cutting oxygen A has a conical shape and gradually comes to naught. A stream of oxygen carries with it the surrounding air, forming a gradually expanding external zone B, filled with a mixture of oxygen with air. Gases of the outer membrane B move in the axial direction, but with a much lower speed, which quickly decreases in the radial direction. The approximate distribution of speeds in the sections of the jet 1-1, 2-2 and 3-3 is shown in FIG. 234.
As they move away from the cut of the mouthpiece, the cross section of the oxygen jet and the velocity of the oxygen in it and, finally, the stream becomes almost unsuitable for cutting. Reducing the cross.section and speed of the jet serves the main cause of the so.called lag in the cutting, which was mentioned above.
The active length of the jet l, suitable for cutting, is determined by several factors, the most important of which are the initial speed and cross.section of the jet, the correctness of its shape, the presence of laminar oxygen in it, as much as possible. The rapid decrease in the cross.section and speed of the jet and the deficiency of its active length are especially affected by cutting large thicknesses. Conventional means of increasing the active length of the jet: increasing oxygen pressure at the entrance to the cutter and increasing the cross.section of the jet are insufficient.
A more attentive study of the process of oxygen cutting leads to the following conclusions.
The decisive indicator for the success of cutting is the speed of oxygen in the cutting stream sufficient to successfully blow the molten oxides from the metal surface in the cutting cavity. When cutting pain. / sewing thicknesses to ensure sufficient jet length, the initial velocity of oxygen should be especially significant.
Oxygen pressure at the entrance to the cutter, providing the necessary initial velocity of oxygen, is determined mainly by the design of the cutter. The imperfection of the design of existing standard cutters is necessary to use significant oxygen pressure at the input to the cutter, as well as quickly increase the pressure with an increase in the thickness of the cut metal.
The main constructive flaws of existing standard cutters are as follows: the unsuccessful shape of the nozzle of cutting oxygen, the presence of sharp deviations of the oxygen path in the cutter, especially when the trunk to the mouthpiece, the presence of sharp changes in the cross.section on the way of oxygen, for example in the valve. The usual cylindrical or step-cylindrical shape of the nozzle unsatisfactorily converts the potential energy of compressed gas into the kinetic energy of the jet at supersonic speeds. A significant amount of energy is lost in the form of sound vibrations, passes into warmth and so on., which necessitates the use of increased input pressures. Sudden deviations of the oxygen pipeline in the cutter and changes in the section increase losses and cause turbulent movements that violate the correct shape of the jet and reduce its stability and working length.
Given what was said, m. M. The board and author of the book designed and built a powerful oxygen cutter R-100 at the Kiev Polytechnic Institute for cutting up to 2 m thick. In the Rezak R-100, schematically shown in FIG. 235, the requirements specified above have been fulfilled. Based on the results of long.term experiments, Sopl has a form shown in FIG. 236 and named by double conuidal. The forming nozzle is built on points on the basis of experimental data. The rezak oxygen.water supply, which leads oxygen to the nozzle, is a straight tube of significant length and diameter. The valve of the cutting oxygen is replaced by a valve that does not narrow the section of the oxygen pipeline. For a mixture of heating flame there are a number of snots located concentrically around the nozzles of cutting oxygen. The cutter of the cutter is cooling with running water to eliminate the possibility of reverse impacts of the heating flame, especially when cutting hot metal, for example in metallurgical plants. The design of the cutter fully justified itself in both laboratory and production conditions. The cutter gives the correct long stream. Oxygen comes out of the nozzle at a pressure close to the environment, and its further expansion in the stream practically does not occur. The stream is stable due to the correct laminar gas flow in it and the lack of twisting. The main technical data of the rezak R-100 are given in the table. 33.
How to use a gas cutter
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Oxygen-acetylene burner is a dangerous method of cutting metal, but with training and observing precautions you can use it to cut steel in shape or size. In order to use a gas cutter, read the instructions given below.
Learn the basics of the cutting process. The initial ignition of acetylene heats steel to a molten state. By adding a stream of oxygen under pressure, the cutter sets fire to steel, which burns through the slot of the cut. That is why the process is called burning steel, and steel and carbon steel are the only materials that you can cut. Aluminum, stainless steel and other metals and alloys cannot be cut with a gas cutter.
- Fire extinguisher. In most cases, a fire extinguisher with compressed air and water is suitable, however, if there is oil, plastic or other flammable materials nearby, a powder fire extinguisher is recommended.
- Tools for marking and measuring. They will help you make the right cut diagram and include a pencil of soap stone, a square and a ruler.
- Protective equipment, including metal cutting glasses and thick leather gloves.
- Corresponding clothes. prerequisite. Do not put on the clothes of free cut, clothes made of flammable synthetic fabrics or clothes with well.worn or torn edges, which lights up easier than tight and filled things. It also implies that you can not wear clothes with free s, cuffs into which slag can get and burn them. Fireproof clothing is recommended, but if you do not have it, put on a well.adjacent cotton. Nylon and most traditional synthetic fabrics quickly burn out from contact with fire!
- It is recommended to shoe strong working boots with a leather sole, since shoes with a rubber sole will burn very quickly under the influence of hot slag. The shoes are preferred, since slag can fall beyond the front edge of the shoes without fasteners, for example, engineering boots or cowboy boots.
- Lighter for a cutter for proper settings of the flame of the cutter. Using matches or lighters for cigarettes is very dangerous; Sensac lighters are designed specifically for this purpose, and their use reduces the risk of serious injuries.
Provide yourself safe working conditions. It is strongly recommended to work on bare ground or on a concrete slab, since sparks from the cutting place fly by meters. Dry materials, for example, paper, chips, cardboard and dry leaves of plants can light up, even if they are at a distance of 4.5 meters or more. Do not let the flame touch the concrete, especially fresh, as this will lead to its expansion and intensive cracking, as a result of which small pieces of concrete take off into the air.
Put the steel that you want to cut on a support located at a working height convenient for you. A steel table is ideal because you can prepare and align the torch, heating and using it. Never use a flammable surface or surface on which flammable materials are spilled. In addition, beware of materials that have oxide.metal coatings, for example, lead paints, chromatic soils and galvanizing. Their couples can be poisonous.
Mark the seats with a pencil of soap stone, leaving a place for grinding, if accuracy is needed. If you do not have a pencil of soap stone, then you can use a permanent marker, but its marks will disappear right in front of the flame of the cutter. In the event that you need accurate cuts, a special saw can give good results, but this is a topic for a separate article.
Connect the tubes to the corresponding cylinders. Bounds and hoses for oxygen, usually green, hoses for acetylene are red, they are pairnly separated so as to connect them to the corresponding cylinders. On the hose for acetylene Reverse thread, And connecting reinforcement is included in the tank to prevent the random rearrangement of these two hoses or tubes. Since the connecting reinforcement is made of bronze, which is easy to damage, twist it with a key with a correctly selected diameter.
- After unlocking the main valve of the cylinder with acetylene, open the control valve, turning the handle clockwise. This must be done very slowly, watching Manometer on the side of low pressure. Open until the displayed pressure is within 0.34. 0.54 atm.
- To blow the air from the acetylene hose, open the gas valve of the cutter until you hear how the gas comes out, and then look at the testimony of the pressure gauge on the side of the low pressure. In the process of purging, the pressure should remain stable. Make sure you have installed this regulator correctly.
- Close the acetylene valve on the cutter.
Where to find the information you need for the selection
Type of combustible gas. here, we hope, everything is quite simple. If you have an old nozzle. look at its marking, it will definitely indicate information on the type of fuel gas. If you select nozzles for a new cutter, then you probably know how fuel gas you have to work.Type of mixing. look at the head of your cutter. If it is injector (there will definitely be a screw for servicing the injector chamber on the head), then you should pay attention to the presence of a uniform nut. If there is a nut, then such a cut under block nozzles, and if not, then for ring slit. By the way, on the injector head of the cutter there will definitely be a marking of the type of combustible gas. If the cutter is a bezine.storage (a casting head without any holes and screws), then only gas mixing nozzles will come to it.
Superficial and curly cutting
In some situations, it may be necessary to create a relief on the surface by cutting a groove on a sheet. If it is decided to use a similar cutting method, then the heating of the metal will provide not only one flame of the cutter. The molten slag will also contribute to its contribution. Becoming liquid, it will spread on the entire surface, which will lead to heating the lower layers of metal.
The first step in the implementation of surface cutting is the heating of the selected area to the ignition temperature. After the starting of the cutting oxygen, you will create a metal combustion zone, and thanks to the uniform movement of the cutter, the fishing line for the cutting trimmer will receive a clean edge. The operation itself must be performed so that the cutter is at an angle of 70-80 degrees with respect to the sheet. When cutting oxygen begins to act, the cutter is placed in such a way that it forms an angle of 17-45 degrees from the treated surface.
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Cutting thick metal with cutter
To create grooves of suitable dimensions, it is necessary to change the speed of cutting: to obtain a greater depth, the speed increases, and for less. they decrease. To create a greater depth, it is necessary to increase the angle of inclination of the mouthpiece, cutting should be performed at a slow pace, while oxygen pressure will also have to be increased. You can influence the width of the groove using the correct selected diameter of the cutting oxygen stream. It should be borne in mind that the difference between the depth of the groove and its width should reach 6 times. over, the last should be the advantage. Otherwise, you can encounter such an unpleasant phenomenon as occurrence on the surface of sunsets.
Advantages and disadvantages
The gas burner is designed to dissect products in production conditions, with a large amount of tasks. Before applying the device, it is important to understand what key features the cutting of metal with propane and oxygen has:
- The mechanism of action is convenient when performing curved cut lines. Stable power allows you to divide the metal products of various thicknesses into parts. In situations where it is impossible to use the tool, such as an angle grinding machine, a gas burner is used. The task of making a round product or a dull type of opening is performed by a gas burner, without requiring special efforts.
- The gas cutter has an advantage, unlike gasoline models. In addition to small weight, the mechanism does not emit increased noise during functioning, as well as compact.
- The use of an apparatus based on the effects of combustible gas allows you to speed up the execution of the execution that mechanical tools cannot do.
- Propane, like gas in a liquid state, differs in a low price. Therefore, it is used not only in the processing of products in production needs, but also in the disposal of metal and other actions.
- The use of propane as a combustible mixture allows you to perform a quality cut. Cutting is carried out according to a narrow besides, which is the main factor in quality work.
The disadvantages can be noted that some materials cannot be treated with propane cutter, such as cast iron and highly alloyed steels.
Features of use
Steel materials with high M carbon is not recommended to cut a gas device. The reason is a high melting point, close to the focus parameter. Instead of a scale thrown out of the exposure of the nozzle, the material with the edges of the edges occurs, the result of which oxygen is stopped, the compound cannot be treated.
Working with cast iron can cause some difficulties, such as the presence of graphite, the form of granularity. Also, gas cutting is not used in cases of copper processing, aluminum, and other easily melting steels.
Principal design of a gas cutter
Injector or two.pipe cutter
This is the most popular model in its design. The name “two-pipe” is due to the separation of technological oxygen into two streams. This is done for the functional separation of oxygen work.
The upper stream of oxygen with high speed goes through the nozzle of the internal mouthpiece. This is an extremely important part of the apparatus. it is responsible for the metal cutting phase directly. This stream is regulated by a special valve, which is usually taken to the outer panel.
The second stream of oxygen goes straight to the injector. The procedure in the injector chamber is as follows: oxygen enters the chamber under high pressure and at high speed, as a result of which a sparse pressure zone is formed in this space. Oxygen is in this case injective.
Nominal gas consumption.
Through the special side holes in the walls of the camera, combustible gas is drawn into it. it is in this case an ejective. The gases are mixed, the speed is leveled, as a result, at the exit from the chamber, a stream of gas mixture is formed, which has a speed lower than that of injected oxygen, but higher than that of the ejected combustible gas.
At the next stage, the formed mixture of gases enters the tip. first into its head, and then through the nozzle between the mouthpieces it goes and forms the very flame in the form of a torch that heats the metal to the temperature of its combustion. All gas flows are regulated by their own valves on the outside of the case. for the supply of oxygen and separately for supplying combustible gas to the injector.
Non.zero or three.pipe gas cutter
In this case, the device of the gas cutter is more complicated. Oxygen gets into it in two pipes, combustible gas is rightfully occupied by the third pipe. In this welding cut, the gases are mixed inside the head, there is no camera here. Such a system is safer than a two.chamber model.
The fact is that there is no risk for the so.called “reverse blow”, which consists in a very unpleasant and dangerous phenomenon: the penetration of burning gases in the channels and tubes of the apparatus in the opposite direction.
This model has the cost is much higher. In addition to this drawback, the three.pipe cutter has another nuance: in working with it you need very high fuel gas pressure. higher than with the injector apparatus.
Standards and dimensions
Welding using a welding burner with gas.
All standard measurements regarding gas cutters are stipulated in GOST 5191-79. Naturally, the weight and size of the devices are directly related to their power. Weight, for example, can only be in two values: the cutters of the models P1 and P2 weigh 1.0 kg, and the high.power model P3 weighs 1.3 kg and not less or less gram.
By the way, the type of combustible gas is also associated with power and size. If powerful p3 cutters operate only on a mixture of oxygen with propane, then a smaller type P1 and P2 device may well function with any type of gas.
Insert gas cutters:
In addition to classic models with different power, there is a separate category. the so.called insert gas cutters with a special labeling of RV. According to GOST, they are called very strange: tips to a gas burner for cutting metal. In general, they differ from traditional cutters: mixing the combustible mixture and oxygen is carried out in the tip itself.
By weight, these devices are much lighter than cutters. RV1 weighs 0.6 kg, and RV2 and RV3. only 0.7 kg. But let this apparent elegance not mislead you. Let’s not forget that these are the tips to the burner, in the kit with which they will weigh no less than ordinary cutters. What is then the advantage?
The fact that they can be purchased for an existing burner and, thus, save some money. And the compactness of the entire kit packaged in a special case. And another important detail that concerns the nature of combustible gas. The fact is that acetylene is much more expensive than propane.
But for welding metal, it is more desirable to acetylene: the burner with it gives a flame with a temperature higher by 400 ° C than the same with a mixture of oxygen with propane.
Portable models: Small ship. Small swimming
There are now many portable options for autogens on the market. this is how they are positioned. They are sold in the form of a nozzle for a compact zani gas cylinder. But in essence and the principle of work, this is a burner. Most of them provide a torch temperature not higher than 1300 ° C.
Of course, there are, of course, portable models of the “professional” series-the zangi cutters, giving the torch temperature above-up to 2000-2500 ° C, which is generally close in terms of indicators to classic oxygen-propy cutter. But physics is physics: even in these models there is no main component that cuts the metal. an oxygen jet that oxidizes this very metal.
Where is a portable gas cutter good? When cutting easily smooth metals or alloys such as tin, brass, bronze, copper. But even these “children’s” options are not cut, but melt. Therefore, compact nozzles. cutters are used more for soldering or welding of small blanks from non.ferrous metals. These can be parts of household devices like a refrigerator or air conditioner. Welding, not a cut, in a word.
In any case, be careful when choosing such models, far from always their proposed “portable” is ultimately justified.
Cutting with an arc
When teaching the basics of welding, the newcomer is most afraid to burn the metal and completely destroy the connection. When cutting the metal, the purpose of the welder is precisely burned, cut the metal.
In order to cut the metal with a welding arc, it is necessary to heat it to the melting temperature and remove the molten metal from the welding zone. Removal is performed under its own weight of the molten metal, due to pressure from the arc or a stream of air supplied to the welding zone.
For cutting metal, these electrodes are used:
In this way, steel is cut, including alloyed, non.ferrous metals and alloys. The disadvantages include low cut quality, uneven edges, the presence of scale. Therefore, if the metal in the future goes to create structures, the edges must be additionally processed, for example, to clean.
Cutting is performed on the same equipment as welding, in all spatial positions. A transformer or rectifier was previously used as equipment at home, now the inverter is most often used.
The basics of arc cutting
In order to cut the metal with an arc, the current strength is set 30-40% higher than when welding. Light a powerful arc on the upper edge of the metal and deepen down, while cutting the edge.
Welding inverter metal cutting
For cutting, select an electrode of small diameter, but the current, on the contrary, is set more than necessary for welding. For example, a 2.5 mm diameter of the electrode, 140A is installed. Light an arc and leave the electrode in one place. You try to go deeper, as if the metal burned. If you place the plate vertically, the molten metal will gently drain. With horizontal cutting metal, a welding inverter of the smudges will be assembled at the bottom of the plate. To ensure the best heating of the metal, during cutting, direct polarity is absorbed. In this case, the metal warms up deeply, but the cut is narrow.
The video shows what opportunities are opened when using a cutting arc. The plate of 10. 20 mm with thickness is cut in just a few minutes easily and beautifully.
Cutting with a gas cutter
Until recently, gas cutting of the metal remained the main way of the metal section, especially if it was required to make a cut along a complex contour, process the edge or get a hole. The advantage is that there is no need for work in the source of electricity to perform work. Metal cutting with a gas cutter is as follows: the mixture of oxygen with combustible gas is ignited, the metal is heated in the cutting zone to the combustion temperature, at least 12,000 ° C. Serve a stream of oxygen.
The metal is ignited and the fishing line for the cutting is obtained. Most often for cutting, oxygen is used in a mixture with propane. Gas harsh steel is both carbon and alloyed, titanium alloys.
Gas cutting of metal on a mixture of propane and oxygen
Prior to the start of work, the metal is prepared: clean dirt, fat, scale, rust.
Gas cutting equipment
To perform gas cutting, less skills are required than when welding, because there is no need to ensure the tightness of the connection. The equipment will require a gas cutter, oxygen and propane cylinders.
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Each cylinder has a gearbox to regulate pressure. Gas from the cylinder to the gearbox is supplied along the high pressure hose. Before starting to work, the hoses are blown to clean from dirt. All hoses are inspected, the joints with the gearbox, all detachable connections are checked for tightness.
Check the serviceability of the cutter itself and blow it with oxygen. To do this, connect a cylinder with oxygen to the place of fastening of an oxygen hose. Bullpiece with combustible gas has not yet been connected. Install 5 atm on gearbox and open both valves on the cutter. By bringing a finger to the second fitting you can observe if there is a suction. In its absence, the channels of the cutter must be blown.
Making Machine for cutting steel
Gas cutting is performed by withstanding the proportion: 10 parts of oxygen per 1 part gas. Therefore, 0.5 ATI is installed on the gas reducer, and on the oxygen gearbox 5 ati. First you open the propane supply slightly and set fire to gas. They rest against the metal with a nozzle and gradually begin to supply oxygen. With the help of rotation of the valves, you can adjust the flame and get the necessary flame for work. The thicker the metal is supposed to be cut, the stronger the flame should be, for which a large supply of gas and oxygen is needed. Attention: Flame is regulated by the pressure of oxygen of the regulatory, and not cutting.
The burning flame is brought to the metal in the place where you need to make a cut, withstanding the distance between the nozzle and the metal of 5mm. Under the action of the flame, the metal is heated to the required temperature. This happens quickly, seconds in 10. Observing the process, they notice that at this moment the metal seems to become wet. Only the metal is ignited, immediately turn on the cutting oxygen. In order to avoid a reverse flame impact, which may be accompanied by a cotton, the cutting oxygen is gradually.
In this case, the oxygen itself will light up as soon as it touches the hot surface of the metal. The video shows how, using gas cutting, you can cut the figures of the most complex shape.
The quality of welding affects the quality of cutting. Control the speed focusing on sparks in the cutting zone. If sparks are ahead, it means that speed is insufficient. At high speed, the spark is behind the cutter, in this case it is difficult to cut the workpieces with high quality. In order to make a hole, the place is heated to the required temperature, cutting oxygen is supplied. The metal is ignited. The cutter is supplied to the metal zone and the hole is broken.
Is metal deformation possible?
Gas cutting involves the thermal effect on the material, as a result of this deformation changes, it is not always possible to avoid. Deformation consists in lengthening, shortening or bending of the product. The cut part can be turned inside or out.
There are factors that contribute to metal deformations:
It is necessary to exclude the effect of these factors, otherwise you will have to correct the resulting defect. There are several simple ways that allow the preparation to return the correct shape: use firing or vacation, apply the editing of steel on rollers.
Deformations can be avoided if you pre.fix the product and warm it up, observe the speed of the gas mixture, and adhere to the correct cutting technology. It is important to sequentially fulfill all stages, choose a cutting mode based on the thickness and type of material. You can not start processing with high gas mixture supply speeds.
In the absence of extensive experience, you should start working with small blanks, and not with cutting out products from whole sheets.
The main equipment for gas cutting is the cutter. The kit includes: nozzle for welding and swimming trunks.
Thanks to the cutter, you can control the dosage of the gas mixture and oxygen. Also, with the help of this equipment, the combustible mixture is ignited, flame supply to the processing site.
The cutter consists of two blocks: cutting and heating. The first is represented by the oxygen jet, valve and an internal.type mouthpiece.
The heating block includes valves that are designed to adjust the pressure of the gas mixture and oxygen. There is also a feed tube, an external.looking mouthpiece, a mixing chamber and an injector cell.
Cutters are manual and machine. The latter are stationary, therefore, it is preferable for repair work to use manual.
Additionally, the following gas.cutting equipment is used:
- gearbox. designed to reduce pressure;
- device for changes in pressure;
- a steel cylinder with gas and oxygen;
- Connecting hoses.
Before using the equipment, it is important to check its serviceability in order to avoid explosion of the cylinder or gearbox. The cutter is pre.blown with oxygen.
Harring the cutter and preparation of metal
This is the opening of the acetylene valve on the cutter and lower the oxygen located in the chamber-mixer. Then the valve adjusting the barely audible gas output is achieved. A special lighter is brought to the cutter and turns on. Before the cutter, a flame of small and yellow should occur.
For work, it is necessary that the flame length is 25 cm. This is achieved by the adjustment of the fluid acetylene.
The next stage is the launch of oxygen. It is carried out by the opening of the corresponding valve until the color of the flame is made of yellow blue. This means that the amount of oxygen is sufficient to fully burn the incoming acetylene.
For effective operation, the supply of oxygen increases until the moment the length of the blue flame located inside does not exceed the thickness of the steel that needs to be cut. If during the operation of the cutter a characteristic “sniffling” or flame is unstable, it should be slightly reduced to the volume of oxygen supplied.
Before you start cutting the metal, its surface should be heated. For this purpose, the cutter is brought to the sheet so that the inner flame is from it at a distance of approximately 1 cm. The heating of steel is performed until the moment of the molten material appears on its surface.
To start cutting the metal should be lowered down with a smooth slow motion handle of the cutting valve. As a result, oxygen will begin to flow to the place of combustion, which must set fire to pre.heated metal. If the material is sufficiently warmed up, the reaction will begin instantly, after which you can further increase the pressure until the metal is completely cut through the metal.
After that, you should gradually move the cutter in the intended direction of the cut. The speed of cutting motion must be selected so that the resulting slag, sparks and drops of hot metal are blown down or drained away from the flame of the burner.
After performing the cut, you should carefully inspect the place of work for the presence of large pieces of molten metal. You should not advance on them in any case, as this can lead to burning even a thick sole. A cut sheet or a piece of metal is cooled by water or naturally.