Mechanized dividing oxygen cutting at different angles. The field of use

Divisive oxygen cutting technology of steel

The quality of the cut and the productivity of the process largely depend on the preparation of metal for cutting. Sheet rental of various brands of steels must be submitted to the workplace of the carrier cleaned of scale, rust and other contaminants.

When cutting in winter conditions, sheets must be served in the workshop in advance so that they manage to heat up to the temperature of the surrounding air. This will reduce the likelihood of cracking on the cutting edge. Profits in the cutting zone should be carefully cleaned of the molding mixture, sand and tanning.

In front of the manual oxygen, a sharp rolling surface is cleaned of scale and rust, usually the flame of the cutting with a narrow strip along the line of the alleged cut. This requires slight warming up the surface of the metal with a heating flame of the cutter, as a result of which scale bounces off from the surface of the sheet.

Before a mechanized harsh leaf, the rental is corrected by rolling on special leaf.line machines and then continuous cleaning. There are chemical, mechanical and gas.flaming methods of cleaning. Chemical cleaning is carried out by etching of steel rolling in a solution of salt or sulfuric acid. In this case, the sheets are laid in special baths. The duration of cleaning sheets from low.carbon and low.alloy steels is 1-2 hours, from highly alloyed. more than 3 hours.

Among the various methods of mechanical surface cleaning, fraudulent cleaning was most common, at which the sheet moves at uniform speed, and the surface of the sheet is treated with a beam of a fraction that flows out at high speed from the fraudulent chamber. This process is environmentally friendly and most productive.

Distance / between the mouthpiece and the surface of the cut metal determines the quality of the cutting and productivity of the process. It is necessary to install the mouth of the mouthpiece at a certain distance from the surface of the cut metal. The following distances are optimal between the ends of the mouthpiece and the surface of the cut metal during acetylene acid cutting of steel depending on the thickness I metal:

5, mm 3-10 10-25 25-50 50-100 100-200 200-300

When working on gases. acetylene substitutes, the recommended distance increases by 30-50%.

To maintain a constant distance between the mouthpiece and the cut metal during manual cutting, special support trolleys are used, with a mechanized. the device for stabilizing the position of the cutter.

Cutting begins with heating the surface of the metal at the starting point of the cut to the temperature of the metal of the metal in a jet of oxygen. After starting the oxygen jet and the beginning of continuous oxidation in thickness, the cutter begins to move along the cutting line. Usually cuts start with the edge of the sheet rental. When cutting the internal elements of the blanks, first it is necessary to break through the hole along the entire thickness of the metal. Punching the initial opening (rice. 5.6) in the steel sheet also begins with heating the surface of the metal. When a given temperature is reached, the valve of the cutting oxygen is smoothly opened and the cutter is tilted at an angle of 5-15 ° to the side, the reverse direction of cutting. At the same time, the cutting of the cutter at a low speed begins to move. After burning the holes, the cutter is installed perpendicular to the surface of the sheet.

With mechanized oxygen cutting, the cutter is fixed in the caliper perpendicular to the surface of the sheet. In order to avoid spraying the output for cutting oxygen and the heating channels of the mouthpiece, the start of cutting is performed according to a special cycle. After the metal heating in the piercing zone, the supply of cutting oxygen of the first stage with a pressure of 98-196 kPa is included (0.98–1.96 kgf/cm 2). At the same time, the cutter with the lifting mechanism smoothly removes from the metal with speed At “ at a distance equal to 3d cut thickness. With the beginning of the launch of the cutting source-

the kind of supply is turned on at a low speed equal to half of the optimal (UR). With this beginning of cutting, molten particles of slag do not clog a mouthpiece, the process of punching the hole proceeds stably. After the cutting of the third part of the path determined for piercing, the full pressure of the cutting oxygen is turned on with the simultaneous lowering of the cutter, which is carried out at the speed Mustache. The hole is burned completely.

When punching the initial opening in the cutting edge of the cut, it is of low quality, so the place of the start of punching during mechanized cutting is located outside the contour of the cut part (when cutting the outer circuit. outside, when cutting the internal circuit. inside).

Punching operations on machines with numerical software and photocopying controls are automatically performed. On thermal cutting machines, it is possible to stably break through the initial holes in the sheet rental with a thickness of up to 100 mm.

After the cutting and exit of the cutter to the contour, the process proceeds stable with properly selected technological modes. For a given cutting speed, a certain value of the lag is set, which increases with an increase in the speed of cutting. The term “lag” is used to determine the distance in the direction of cutting between the axis of the nozzle and the point on the lower side of the cut leaf, where the stream of cutting oxygen comes out (rice. 5.7).

If necessary, cutting from a sheet of different sizes of parts, it is necessary to cut from the edge of the sheet and move along its short side (rice. 5.eight). The direction of bypass of the circuit is selected in such a way that the edges adjacent to the metal going to the departure are primarily processed. Last of all, a cut should be performed that separates the part from the bulk of the sheet. When cutting, the rigidity of the cutting should be less than the stiffness of the cut part, so the waste cut should be provided.

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If you lay nonsense into a computer, he will not give out anything but a nonsense. But this nonsense, having gone through a rather expensive car, is in no way ennobled, and no one dares to criticize it. Laws of Mea (more. )

Machine oxygen cutting replaces such labor.intensive mechanical processing operations as strict, milling, dolbyly, etc. Figure cutting is used in all areas of industry. She became especially widespread at heavy and transport engineering plants, in shipbuilding, as well as when performing installation and construction work, where cut parts are not subjected to subsequent mechanical processing. [one]

Machine oxygen cutting allows in some cases to abandon not only milling work, but also from labor.intensive fucking, strict, blacksmithing operations. [2]

During machine oxygen cutting, the operation of the charts for welding is widely used. [3]

During machine oxygen cutting, the surgery for welding for welding is widely used. [four]

With manual and machine oxygen cutting, the metal is heated due to combustion of gas (acetylene, gas-replacement, vapors of kerosene or gasoline) at the temperature of ignition and in the jet of cutting oxygen. [5]

Further development of machine oxygen cutting should be expected in these progressive directions. As for the manual oxygen cutting, it will be used in workshop conditions and on installation to perform cuts of small length and in hard.to.reach places. [6]

The effect of the parameters of the machine oxygen cutting on the accuracy elements of the cut edges and the width of the cut: A. cutting speed; b. oxygen pressure; in. The height of the cutting of the cutter. [7]

Complete automation of machine oxygen cutting is achieved by the use of cutting machines with software control. [eight]

Details carved by machine oxygen harsh. often go to the assembly of products without subsequent machining. In the event that the circumcised edges of the parts experience alternating loads during operation, then increased requirements from the point of view of the quality of the cutting surface are imposed, since the risks remaining after oxygen cutting on the edge are stresses. [9]

With proper organization of labor, machine oxygen cutting is a high.performance process. [ten]

The influence of various parameters of the mode of machine oxygen cutting on the accuracy elements of the cut edge (excluding the cutting out as a result of random deviations from the norm) and the cut width for low.carrier steel 26 mm thick is given in FIG. [eleven]

These indicators belong to the machine oxygen cutting of low-carbon steel oxygen of the 1st and 2nd grades. [12]

So, a stationary working post for machine oxygen cutting includes the machine itself, a cutting table with a ventilation system and gas.fading posts located on gas pipelines, from which gases are supplied to the cutters. [13]

Thus, a stationary working post for machine oxygen cutting includes the machine itself, a cutting table with a ventilation system and gas.divided posts located on gas pipelines, from which gases are supplied to the cutters. [fourteen]

The use of 99 5 % or more is most advisable and economically justified by the use of oxygen. [fifteen]

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Separation cutting usually begins from the edge of the sheet. First, the metal is heated by a heating flame, and then the cutting stream of oxygen is started. After turning on the cutting stream of oxygen, the cutter evenly moves along the cutting contour. The speed of the cutting of the cutter should be maintained by constant. From the surface of the metal, the cutter must be at the jack of distance so that the metal is heated by the recovery zone of the heating flame that is detached from the kernel by 1,5. 2 mm. For cutting thin sheets up to 8 thick. 10 mm is used package cutting. With package cutting, the sheets are tightly laid on each other and compressed with a clamp. The presence of significant air gaps between the sheets in the package worsens the cutting. [one]

Separation cutting usually begins with, the edges of the sheet. At first, the metal is heated by a heating flame, and then cutting a jet of oxygen starts. After turning on the cutting stream of oxygen, the cutter evenly moves along the cutting contour. The speed of the cutting of the cutter should be maintained by constant. From the surface of the metal, the cutter should be at such a distance that the metal heating is carried out by the recovery area of ​​the heating flame that is detached from the nucleus to 1 5. 2 mm. For cutting thin sheets up to 8 thick. 10 mm is used package cutting. With package cutting, the sheets are tightly laid on each other and compressed with a clamp. The presence of significant air gaps between the sheets in the package worsens the cutting. [2]

The dividing cutting is used for cutting blanks, cutting metal, cutting the edges of the seam for welding and performing other operations to cut metal-on part. [3]

Separation is carried out without and with a bevel of edges for welding, and surface cutting is either continuous when the entire surface of the workpiece is processed in one pass, or selective with local removal of the surface layer of metal. [four]

Separation cutting. The cutting stream is directed normally to the surface of the metal and cuts it out to the entire thickness. Surface cutting. The cutting stream is directed at a very small angle to the surface of the metal (almost parallel to it) and provides its coarse strict or peel. It is removed by superficial casting defects. [6]

Separation cutting. The cutting stream is directed normally to the surface of the metal and cuts it out to the entire thickness. [eight]

Separation is carried out without and with a bevel of edges for welding, and surface cutting is either continuous when the entire surface of the workpiece is processed in one pass, or selective with local removal of the surface layer of metal. [9]

Dividing cutting is used to separate part of the metal. The cutting oxygen stream is usually directed at an angle of 90 to the surface of the cut metal, and it cuts through the metal through its entire thickness. [ten]

Separation is carried out by a non.melting electrode: coal, graphite or tungsten. [eleven]

Separation cutting along the contour inside the sheet begins with a hole punching. A machine cut can be broken in a sheet with a thickness of up to 100 mm. [12]

Separation cutting along the contour inside the sheet begins with a hole punching. A machine cut can be broken in a sheet with a thickness of up to 100 mm. First, heated by a heated flame, the punching place to the ignition temperature of the metal in a jet of oxygen. Then they gradually open the valve of cutting oxygen, while lowering the cutter, and slowly increase the pressure of the cutting oxygen to the optimal. When working on modern automated machines (machines with software and photocopyrov. [13]

Separation cutting is widely used for cutting sheets and cutting a profile metal. The preparation of the cut metal has a great influence on the quality and performance of the cutting. First of all, from the surface of the metal, it is necessary to remove rust, scale, paint and other contaminants. The gap between the floor and the lower surface of the cut should be at least 100. 1500 mm, which will provide unhindered removal of slags from the cutting zone. [fourteen]

Dividing cutting counts up to 300 mm thick is carried out by oxygen-fluid cutting with URHS-type installations or plasma-spirit method. However, the cut surface is hardened and cannot be processed with a cutting tool. Surface cutting (string) or airborne cutting is used both for removing various surface defects such as halts, and for cutting flooded holes, as well as for partial replacement of stump operations, especially in the presence of bays of increased thickness. The power source is the TDF-2000 transformer. Graphite plates (15 x x 25 x 250 mm) are used as electrodes, the surface of which is covered with a mixture of aluminum with aluminum oxide. Cutting mode: current strength 1100. 1300 a; compressed air pressure 4. 6 kgf / cm2 (4. 6. 105pa); Cutting speed 400. 700 mm / min; The thickness of the removed metal by the passage. no more than 15 mm. [fifteen]

Metals with a thickness of 3 to 2000 mm are cut with a gas.acid harsh

According to the method of execution, oxygen cutting is divided into dividing and surface.

The dividing cutting is designed to cut the blanks, cutting the sheets and the performance of the dismantling work associated with the separation of metal into several parts. The metal is cut to the entire thickness.

Surface cutting is designed for cutting grooves on metal, removing surface defects on castings, rolling and welds, to remove the heads of rivets, remove the surface layers of the metal. With surface cutting, layers of metal are removed to a limited depth as a result of a large mouthpiece of the cutter.

Spear cutting is used when burning holes in the metal of a large thickness and in the processing of non.metallic materials, for example, concrete.

Not all metals are cut with oxygen, but only those that satisfy the following requirements:

The melting temperature of the metal should be higher than the temperature of its ignition in oxygen. Otherwise, the metal will melt, not burn and poorly warm up the lower layers, weld to the edges, the edges will be torn. Carbon significantly reduces the temperature, so high.carbon steels and cast iron to cut oxygen is almost impossible.

Metal melting temperature should be higher than temperature melting his oxides. Otherwise, the oxide film will prevent oxygen access to the metal and the combustion of metal (its cutting) will not occur.

The amount of heat released during the oxidation of the metal of the metal should be large enough to automatically continue the cutting process without the need to communicate heat from the outside. So, the thermal effect of the formation of copper oxides, nickel, tin is very low and it is almost impossible to cut such metals with oxygen.

Oxides formed during cutting, There must be fluid. Otherwise, when cutting, slag is poorly blown away. So, silicon oxides, chromium and some other elements have a small liquid flow. They are very viscous, so they do not flow, but stick to the cuts of the cut and it is very difficult to remove them. Such alloys include, for example, cast iron, chromium steel.

Thermal conductivity of metal should be low, so that the initial reported heat for heating the metal to the desired ignition temperature in oxygen is not redistributed to a large area due to heat transfer. Due to the high thermal conductivity of copper, aluminum and their alloys, it is impossible to cut them with an oxygen stream.

The alloy should contain The minimum amount of impurities, increasing its prosperity. So, when cutting steels with high M carbon, silicon, chromium, nickel, molybdenum, tungsten, the cuts of the cut are hardened, their hardness and fragility increase, which leads to the formation of cracks.

The most fully listed requirements are satisfied by steel with carbon of less than 0.7%. They do not meet these requirements and do not lend themselves to oxygen cutting: steel with a large carbon, highly alloyed steel, stainless steel, non.ferrous metals (copper, aluminum, titanium) and their alloys.

The main technical and economic indicators of gas acid cutting, which determine its quality, performance and efficiency, include: the consumption and purity of oxygen, the power of the heated flame, the speed of cutting, the distance from the flame of the flame to the cut metal.

The consumption and purity of cutting oxygen should be quite defined for the process. The lack of oxygen in the cut zone leads to incomplete oxidation of the metal and not sufficiently intense removal of oxides; Excess oxygen. to cooling the metal and removal of heat from the cutting zone. With a large excess of oxygen, the cutting process may stop. According to GOST 5191-79 during manual cutting, oxygen consumption depends on the thickness of the metal as follows:

When leaving the nozzle, the cut of cutting oxygen should have a bright blue color and maintain a cylindrical shape on the possible length to provide a uniform cut width along the entire thickness of the metal. The flow of the flow of oxygen is affected by the shape of the channel of the mandstock nozzle. Use nozzles with output channels of cylindrical, step-cylindrical and expanding forms. When leaving the cylindrical channel of the nozzle, a stream of cutting oxygen at a certain distance from it has the form of a truncated cone. Particles of oxygen at the same time lose their speed and direction, which reduces the speed and quality of cutting. Such nozzles are used for cutting metal of small thickness. up to 20 mm. Nozzles with step cylindrical channels are widely used when cutting metal 12 200 mm thick. The maximum speed of oxygen in the length of the cylindrical part of the jet provides nozzles with an expanding channel, but they are difficult to manufacture and are used for cutting metal of a large thickness. The lower the purity of oxygen, the more it sticks a difficult grocery (slag with unburned metal) on the lower edge of the cut, preventing the movement of the jet and the output of cutting products. The minimum purity of oxygen, in which you can get a cut without a grata, is 99.2%, but at the same time the cutting rate is low, and the oxygen consumption is large. The most effective non.gag cutting process of steel up to 100 mm thick is reached with an oxygen with a purity of 98.0%, the cutting rate decreases by 29%.

The heating time of steel for punching holes using various gases burning in oxygen in seconds:

Gas cutting equipment

So, in the time of the USSR, the rezak P1-01 was considered the most common. It is manual with an injector nozzle, which gives a stream under high pressure, which cuts the metal “like a hot knife oil”.

powerful models are P2-01 and P3-01P. Their main difference is the size of the nozzle, the working pressure of oxygen in the system, the working pressure of the heating mixture supply.

There are also autonomous tables. these are gas equipment for cutting metal in automatic mode, which is produced without the participation of the operator.

Management of such a table is a number-program. That is, a person simply sets cutting parameters.

Such equipment for oxygen cutting of metal is used exclusively on sheet metals, where either even cutting or arc.

It is worth noting that the models of these tables are a huge number, but almost all of them are Analogues of the An-01, which was developed by Shepelev back in the USSR!

These, for example, are “shift”, “orbit”, “secretor”, “Quicky-E”. In all of them, the operating temperature in the range of 1000-3200 degrees Celsius. Work with both acetylene and propane heater.

Quicky also uses mixed-acetylene-propane heating in models. In this case, the nozzle only bifurcated is used. That is, acetylene is supplied to one of them, propane for the second.

It is important to know: longitudinal metal cutting. machines, lines, units

By the way, it is worth noting that in such a cutting, the heating mixture lends itself to the center (that is, from the oxygen stream).

The so.called stationary cutters for gas cutting metal are also noted.

They differ from the mobile, it is not difficult to guess, in that they are built into a special niche-station, which the device operator can just move.

Such cutters are more convenient for work, but are very expensive. But their cutting power is more than enough to cut a thick layer of high.strength metal!

This became possible due to the fact that such cutting uses an additional superceter, with which that the heater, that the oxygen stream is supplied under even greater pressure.

There is an additional compressor on electricity, in addition, three.phase (380 volts). Because of this, he cannot be mobile! Such a cutter is used exclusively in professional enterprises.

Guguga is the most popular representative of such cutters.

By the way, there are also two types of gas burner for metal cutting. the so.called straight and bent:

• The first is the one that you are all used to seeing. Is the letter G and works with the help of the operator direction.
• Well, the second, straight line is a burner like a nozzle that is used on the tables-cuts.

It is also worth noting that in direct nozzles, paired tips are used in order not to violate the angle of inclination of the nozzle one to one when moving.

By the way, take into account that each of the cutters has its own work coefficient and power with each metal.

For example, when using the standard P1-01 to cut copper, a coefficient of 0.5 acetylene is enough, but for aluminum it will take as much as 0.7.

Most of all, of course, will go to the tungsten. as much as 1.4! At the same time, heating will be around 3800 degrees Celsius (use only specialized tips)!

Conditions for gas acid cutting

For the successful use of gas acid technology of metal cutting, a number of prerequisite should be observed:

• The melting temperature (tlav) should exceed the combustion temperature (tvospl) in the oxygen medium. The difference should be at least 50 ° C to exclude the flow of the melt and unjustified expansion of the section of the section. So, for structural alloys tplav = 1540 ° C, and tvospl = 1150 ° C. With an increase in carbon content, the melting temperature decreases. This makes it difficult to cut cast iron and high.carbon alloys with an ordinary cutter.
• The tplaw of the cut material should exceed the tplaw of oxide films on its surface. The refractory oxide film will prevent oxygen access to the metal surface and the combustion reaction cannot begin. So, chromium oxides and structural steel 3 have melting temperatures, respectively 2270 and 1540 ° C, respectively. The way out of this situation may be the use of flux powder, which reacts with an oxide film and converts it into substances with a lower melting point.
• Oxides arising during the cutting process should have a high fluid. If the fluidity is low, then they put on the edges of the cut line, preventing the burning of the main material. A specially selected flux powder also helps to solve this problem, increasing the fluidity of oxides. But this leads to a rise in the cost of the process.
• The cut material should have low thermal conductivity. Otherwise, heat will be removed from the working area and the temperature of the metal fire at the venue will not be achieved. The reaction will not begin to begin or will proceed unstable, increasing gas consumption, reducing the accuracy and quality of the cutting surface.

Oxygen cutting technology

This type of processing is used only if special operations are necessary: ​​rescue, construction, emergency, lifting. The cutter for underwater cutting can be cut by steel alloys up to 70 mm thick, while at the same time at a depth of 30 m. A gas acid cut can work with steel, the thickness of which reaches 100 mm.

By the type of cut, they are divided into:

The manual method of oxygen cutting is used to process the ends of the pipeline before welding, to remove defects. The operation can be performed in any spatial position. For its implementation, insert and universal cutters are used. The setting of the mode depends on the thickness of the processed product.

By the method of processing cutting is manual and mechanized. There are manual cutters, the work of which is characterized by a fairly high accuracy, they are divided into universal, special, for figure and direct cutting. If it is necessary to process large volumes of metal, it is rational to use the portable devices “Guguga”, large batches of the same products are successfully cut out with the help of ASSH-86 hinged machines. Industrial enterprises most often use portal-console devices.

Cutting modes

Cutting technology implies the optimal choice of parameters for processing the required material.

The parameters are folded from the power of laser radiation, processing (feed), the diameter of the nozzle, the focus position and the pressure of technological gas. If everything is selected correctly, then you will achieve a quality cut.

Often, the manufacturer gives the processing tables (reference), but in our realities they remain reference, since all requirements are very often not possible to comply with all the requirements.

And so, there are several types of laser cutting:

When cutting with melting, the beam heats the metal to a state of fluidity, and then there is a queue of oxygen, which blews the products of the melt from the cutting zone. Oxygen also acts as a catalyst. Cutting with melting is used exclusively in the oxygen environment. With its help, the metal of a large thickness is processed. But it is also actively used for processing small thicknesses (nitrogen and oxygen vary greatly).

Sublimation cutting is used when cutting thin sheet metal using inert technological gas. In most cases, this is nitrogen. When cutting, a laser beam evaporates the metal in the cut zone and blews it with technological gas.

With this type of processing, it is worth considering that the diameter of the nozzle increases, and the gas pressure decreases as the metal thickness increases. The speed is selected in fact and it is reduced when the thickness is increased. The position of the focal point is on the metal. The higher the thickness, the higher the focal point.

With sublimation cutting, all parameters change to the opposite, except power. There are a lot of power, you can even say the more, the better. The speed is selected in fact, it also decreases with increasing metal thickness.

Why is this happening? This is due to the difference in the selection of processing.

When cutting with melting, it is necessary to create a large melt bath and increase the thickness of the cut so that the gas can remove combustion products from the cutting zone. And with sublimation cutting, it is necessary to save all the energy of the beam in one small zone (therefore the focal point is in metal) and after evaporation or boil, quickly remove evaporation or boil products from the cut zone with a large amount of gas.

Below are tables with indicative cutting speeds of the main metals with fiber lasers of IPG Photonics of various capacities

Carbon steels (harsh oxygen), mm/min

Aluminum and its alloys (harsh oxygen), mm/min

Mechanical cutting of metal

Mechanical separation is based on direct contact of the processed metal with a cutting tool. The material of the tool, as a rule, is also metal, but higher hardness.

Distinguish mechanical cutting using scissors, saws, incisors. A particular case of mechanical cutting is a shock (cabin). Shock cutting or cutting using guillotine is used at the stage of procurement work.

Types of equipment used for the mechanical separation of materials:

• ribbon-saw machines (LPS);
• guillotines;
• disk machines;
• turning machines with incisors installed on them;
• Longitudinal cutting units.

Cutting tape saw

Cutting the material with a tape saw is often used to separate varietal, sheet metal. Ribbon drain-the main knot on the so-called tape-saw machine (LPS). The essence of the work of the tape saw is the same as the usual hacksaw. The saw canvas is closed into a large diameter tape, one side of which has special teeth. The saw tape moves continuously due to the rotation of pulleys connected to the electric motor. The average cutting speed of the machine is 100 mm/min. The material for the manufacture of the saw canvas is a carbon steel or bimetallic alloy.

The advantage of the method: accuracy, availability, low price of equipment, the ability to perform not only straight, but also angular cut; small percentage of waste, since the width of the cut is only 1.5 mm.

Modern LPS models are equipped with electronics and additional equipment, with which you can include a machine in the technological line.

Shock cutting of metal on guillotine

This species is usually called the trigger. The main scope of cutting is the separation of sheet metal. It can be black metal, various types of steel. stainless, galvanized or electrical steel.

The method is based on the use of mechanical devices: scissors, knives for cutting a metal sheet. The metal sheet is placed on the working surface of the guillotine. Fixed with a clamping beam and perform an operation.

The uniqueness of the method is that the cutting (cutting of the metal) occurs with a simultaneous blow of the knife along the entire length of the cut workpiece. The result is an absolutely even edge without unnecessary edges and burrs.

Three types of guillotine are used in industrial production:

In some industries, manual guillotine scissors have been preserved, where the cutting mechanism turns on by pressure on the pedal.

The disadvantages include noise during the operation of the mechanism, restriction on the thickness of the workpiece, the difference in width in cut parts.

Cutting on a disk machine

The main advantage of this equipment is ease of operation, compactness, versatility.

The role of the cutting tool is played by a disk with teeth, protected by a casing. The disk is mounted on the surface of the desktop, driven by the electric motor.

Cutting with a disk saw is characterized by high cut quality, the possibility of cutting at an angle, high accuracy of processing.

Longitudinal cutting unit. highly specialized equipment, which is operated exclusively for the longitudinal separation of a metal workpiece.

The cutting process is fully automated. The operator monitors the process and manages the work, being a special remote control.

The uniqueness of the method: the ability to divide the sheets into narrow elements of large lengths (tapes, stripes, strokes).

The general disadvantages inherent in all types of contact cutting can be formulated as follows:

In modern technologies, the latest methods of separation of metal are used, in particular, cryogenic (surgery using the supersonic flow of liquid nitrogen).

Cutting, metal cutting. primary procurement stages of metal processing and alloys. The use of direct.ilated blanks of the correct shape, as the final product of metal processing, is limited. After cutting by mechanical methods and a gas acid harsh part, they are transmitted for mechanical processing. But using thermal operations of laser and plasma cutting, you can get parts that are the final product. These will be parts of a complex configuration with cut openings, cuts and other elements.

The essence, use and equipment of oxygen-fleece cutting

Oxygen cutting of metals is based on the property of heated metal intensively burn in a stream of oxygen. The metal at the site of the cut is heated by a gas flame to the temperature of its ignition in oxygen and a stream of cutting oxygen is directed to the heated surface. The ignited metal burns out, and the resulting oxides are blown away by a stream of oxygen.

To carry out the process of oxygen cutting, the following conditions are necessary: ​​the combustion temperature of the metal in oxygen should be lower than the temperature of its melting; Metal oxides formed during cutting should melt at a lower temperature; than the combustion temperature of the metal; Thermal conductivity of the metal should be low; The amount of heat released during the combustion of the metal should be large enough to ensure the continuity of the cutting process; The consistency of the oxides of the metal should be liquid. The most accurately listed conditions are met by steel.

Cutting process (rice.82) begins with the heating of metal 1 at the starting point of the cut to the ignition temperature of this metal in oxygen. Heating is carried out by a heating flame 3, which is formed during combustion of combustible gas in oxygen. When the metal heating temperature reaches the required value, a stream of cutting oxygen 2 is allowed.

Cutting oxygen enters heated metal and lights it. When the metal is burned, heat is released, which, along with a heating flame, warms the underlying layers, and the combustion spreads to the entire thickness of the metal. Oxides 5, which are generated during the combustion of the metal, being in a molten state, are fond of a stream of cutting oxygen and blown out of the cutting zone 4. If you move the cutter along a given line at the proper speed, then the cut form will correspond to a given configuration. Rice.82

Gas acid cutting is widely used in almost all areas of the metallurgical and metalworking industry. It is used for cutting sheet steel, when cutting a profile metal, when cutting the scarves, circles of flanges and other shaped blanks.

For heating steel to a temperature of 600 700 ° C, combustible gases are used: acetylene, natural gases, vapors of gasoline and kerosene.

Gas.flame oxygen cutting allows you to cut metal up to 300 mm by equipment, cutting at installation, and field conditions. In this way, low.carbon and low alloy steels are cut.

Cutting can be manual and machine. For manual cutting, a universal cutter of the UR type is used (rice.6) having interchangeable mouthpieces.

A universal cut, like an injector burner, consists of two parts: body and tip. The cutter has an injector device that provides normal operation at any gas pressure. Rice.83

There is an additional channel in the Rezak 2 to supply cutting oxygen. Rezak head one It consists of an internal mouthpiece, according to which cutting oxygen comes out and an external mouthpiece. Acetylene. oxygen mixture, which heats the metal at the site of cutting, is supplied to the ring gap between the internal and external mouthpieces.

Universal injector cutting equipping with two external and five internal mouthpieces. This cutter can be cut low.carbon steel with a thickness of 3 to 300 mm. Formed mouthpieces are selected depending on the thickness of the cut metal. For example, for cutting it became a thickness of 3. 5 mm use external and internal mouthpiece. 200 thick. 300 mm. external mouthpiece, and internal. oxygen pressure during gas cutting is set within 0.2. 1.4 MPa, depending on the thickness of the cut metal, and acetylene. not lower than 0.001 MPa.

Machine cutting is performed by naatomats and semiautomatic devices that have one or more cutters that allow you to cut along a complex contour.

As equipment for gas cutting, oxygen and acetylene cylinders are used. Instead of an acetylene cylinder, an acetylene generator can be used.

3.By the nature and direction of the oxygen stream, 3 types of cutting are distinguished:

While doing dividing oxygen cutting It is necessary to take into account what requirements are for the accuracy of cutting and the quality of the surface of the cut part. The lower these requirements, the less oxygen and fuel are consumed and the greater the speed of cutting can be.

For example, during cutting cutting (cutting in scrap), the surface quality and the accuracy of cutting do not matter. Therefore, cutting is carried out manually at the highest possible speed.

During procurement cutting (the workpiece is cut out from which the part is made by mechanical processing), the cut quality does not matter, but a certain size of the workpiece should be maintained with the lowest allowances for mechanical processing. Cutting is performed manually. In this case, the simplest devices (support rollers, compasses, guide carts, etc. are often used. P.), with the help of which it is easier to withstand the set allowances.

Cutting for welding should be carried out so that there is a clean cut surface and the specified sizes of the part were observed. Requirements increase when the parts are prepared for automatic welding. In this case, usually mechanized cutting is used.

The final clipping of round and shaped parts, which will be used without subsequent mechanical processing, is made only by automatic machines.

Thus, depending on the type of oxygen dividing cutting, it is necessary to achieve a certain quality of the cut.

Поверхностной кислородной резкой называется процесс снятия слоя металла с поверхности обрабатываемой детали, выполняемый посредством кислородной струи.

В отличие от разделительной резки, при которой кислородная струя направляется перпендикулярно поверхности обрабатываемого металла или углом вперед с углом атаки φ = 45° и более, при поверхностной резке угол атаки меньше и составляет обычно 10…30°. В результате наклонного направления струи и малой скорости ее истечения в связи с применением относительно небольших давлений кислорода (редко выше 4…5 кгс/см 2 ) и больших сечений выходных каналов для кислорода, струя, врезаясь в подготовленный в тепловом отношении металл, деформируется и выбрасывается в сторону той же поверхности, с которой она и была введена. На эту же Рис.84

Виды кислородно-флюсовой резки

Технологией кислородно-флюсовой резки производят обработку металлов напором газового пламени, смешанного со струёй кислорода, которая выполняет функцию «режущего пламени». Таким способом резку прочных металлов можно делать и вручную, и как механически. Для автоматической кислородно-флюсовой резки используют газорезательные устройства, в которые устанавливают резаки. Аппаратами мастер может делать поверхностную резку или разделительную. При ручном раскрое используют специальные держатели, в которых также под напором подаётся газ и кислород. И ручным, и машинным способами можно обработать высокопрочные металлы толщиной до двухсот миллиметров на большой скорости (около 300-700 мм/мин).

Обработку металлоизделий кислородно-флюсовым способом совершают на специальных устройствах. В конструкции аппарата предусмотрены такие элементы как резак, флюсопитатель, передатчик флюса в резак. Металлорежущий инструмент в устройстве имеет больший диаметр, по сравнению с аналогичным аппаратом для резания только кислородом. В роли горючего сырья выступают окислители, пропан, азот, флюсонесущие газы, СО2. В ручном процессе разрезания помогает аппарат копьедержатель “КД-1”. Машинную резку флюсом и кислородом осуществляют на портальных автоматических устройствах и установках УКФР-6М. Аппаратами для ручной и автоматической резки обрабатывают такие материалы как стали, чугун, бетон, алюминий, различные сплавы цветмета.

Процесс кислородно-флюсовой резки высокохромистых сталей

Изделия из высокохромистой и хромоникелевой стали невозможно обработать одним кислородом из-за того, что, окисляясь, хром становится тугоплавким, и его сложно удалить из среза заготовки. Для таких материалов была изобретена технология кислородно-флюсовой резки. Стальные заготовки с высоким м хрома режут струёй кислорода, в которую добавлен порошок (флюс). Порошковое вещество сгорает, соприкасаясь с кислородом, тепловая отдача усиливается, и хромистая сталь начинает плавиться точно в местах резки. Работа по такой технологии получают чистую поверхность разреза.

Чугунные изделия плавятся при очень высоких температурах, поэтому для чугуна также применяют процесс обработки кислородным флюсом. Кислородная резка не подойдет из-за того, что в составе чугуна содержится кремний, который образует под воздействием СО2 прочную плёнку. Расплавить её, чтобы получить аккуратный рез на изделии можно только с добавлением флюсового порошка. Кислородно-флюсовая резка чугуна предотвращает загрязнение кислородной струи и не даёт произойти окислению в местах разреза.