How to properly cut with a gas cutter

Beginning of work

How to cut metal with a gas cutter. after completing the preparation, the performer slightly opens the propane valve, ignites the gas stream, while the nozzle of the product rests on the metal surface. Now you need to adjust the flame strength, alternately adding propane and oxygen. After setting the optimal force of the burning mixture jet, the product is located at a right angle to the surface of the part, the nozzle is located no closer than 5 mm.

If the cut starts in the middle of the sheet, then the starting point is set at the beginning of the cut. The surface heats up to a temperature of at least 1000 0 C, it looks like it gets wet, then the oxygen supply increases to form a powerful narrowly directed jet.

Preparatory work

How to set up a torch for cutting metal. first of all, you need to make sure that the product is in good condition, ready for work, then the following procedure is performed:

  • The hoses from the cylinders are connected to the cutter by pre-blowing the product to remove foreign inclusions from the inside.
  • Oxygen is connected to the right hand thread and propane to the left hand thread.
  • Set the propane supply level to 0.5, and oxygen supply to 5.0 atmospheres.
  • We check the connections for leaks, as well as the operation of reducers and pressure gauges.

If gas leaks are found, then the nuts are tightened or the gaskets are changed.

The diagram shows the correct connection of the cylinders to the cutter.

Danger of kickback

If the jet burns incorrectly, cotton occurs and the flame is drawn into the inside of the product, which leads to an explosion, since the fire spreads through the hoses and reaches the containers with gases. To prevent a hazardous situation, the torch is equipped with a check valve that cuts off the flame and prevents it from spreading.

Nuances

The main task of the performer is to maintain the speed correctly:

  • normal mode. sparks fly at right angles relative to the surface of the workpiece;
  • low speed. flying away from the performer and an angle of less than 85 degrees.

After the end of the process, the oxygen supply is first shut off, and propane is turned off last.

N. Ishkulov, education: vocational school, specialty: fifth grade welder, work experience: since 2005: “For the first time cutting with oxygen equipment, it is necessary to remember that after a sudden stop it is necessary to start a new cut from a different point, and not there where the process ended “.

Equipment set

Before starting flame cutting or welding, the equipment should be carefully prepared:

  • Containers with gases.
  • Connection hoses.
  • Cutter.
  • A mouthpiece with specific dimensions.
  • Volume control and control reducers.

The equipment does not depend on the manufacturer, the valve marking is standard.

How to cut metal with a gas cutter: equipment

Cutting metal with a gas torch is a simple process compared to similar welding, which does not require special skills from the performer. The main thing for the contractor is to study the technology of cutting metal using equipment operating on a mixture of propane and oxygen, which provides stable combustion and high temperature, which allows you to burn through almost any metal.

Negative deformation

Novice welders are concerned with the question of how to use the propane oxygen cutter correctly so that the surface of the part does not warp. First you need to figure out what factors contribute to the occurrence of these defects:

  • with uneven heating of the surface;
  • high speed cutter was selected;
  • there was a sharp cooling of the heating place.

In order to exclude the occurrence of the above factors on the workpieces, they are previously securely fixed and heated, and the speed is increased gradually. If warpage still occurs, then you can return to its original shape by firing or tempering, and the sheets can be straightened on rollers.

Pros and cons

Gas cutting and metal welding has many advantages, but we are only interested in cutting, which has the following advantages:

  • It is in demand when a thick metal is cut or a stencil cut is needed, and an angle grinder cannot cope with curved sections.
  • The gas analogue is much more convenient for work, has a low weight, operates twice as fast as equipment with a gasoline engine.
  • Propane is cheaper than acetylene and gasoline, so its use is more cost-effective.
  • The cut edge is much narrower and the structure is cleaner than from an angle grinder or gasoline equipment.

Disadvantages. a narrow range of metals subject to similar processing.

Gas torch basics

The process of cutting with a gas torch occurs due to the combustion of metal in a stream of oxygen supplied under pressure. The alloy must be preheated to the required operating temperature using a burning mixture of acetylene and oxygen. The only metals that can be cut in this way are various grades of carbon steel and unalloyed steel. Stainless steel, non-ferrous metals and alloys cannot be cut with an oxygen-acetylene cutter.

To perform this type of work, in addition to the corresponding set of gas equipment, you will need the following:

  • Fire extinguisher.
  • Protective equipment: special glasses; thick leather gloves; sturdy work shoes with leather soles.
  • Appropriate clothing. It is recommended to wear fire resistant clothing, but if not available, a well-fitting cotton will do. Do not wear clothes made of synthetic and flammable fabrics, loose fit, with torn or worn edges.
  • Measuring and marking tools: ruler, square and soapstone pencil.
  • Torch lighter. designed to properly ignite the torch flame. It is very dangerous to use ordinary matches, lighters.

Igniting the torch and heating the metal

  • make sure that all connections are tight (valves, pressure gauges, hoses, other fittings). any gas leak can instantly cause a fire;
  • check again the place of work for the absence of flammable materials, strangers (especially children), animals;
  • make sure that you are ready to work;
  • wear safety glasses and gloves.

The acetylene valve is then opened on the torch, allowing the oxygen that is in the mixing chamber to escape. A few seconds are enough for this. Then the valve is turned on until it becomes audible that the acetylene is barely coming out. A special lighter is placed in front of the cutter, as shown in the video, so that its inside touches the mouthpiece. Then press on the lighter lever. When the sparks produced ignite the acetylene, a small yellow flame should form in front of the mouthpiece.

By turning the gas supply valve, the flame length is increased to about 25 cm. The torch should start at the very mouth of the torch. The flame will burst from it or jump when too much acetylene is supplied.

Open the front oxygen valve slowly. In this case, the flame should change color from yellow to blue. at this moment, the supply of such an amount of oxygen will be provided, which is sufficient for the complete combustion of acetylene. The oxygen supply should be increased until the inner blue flame tongue diminishes and contracts towards the mouthpiece.

The oxygen valve is opened even further. the size of the torch is increased until the length of the inner flame becomes slightly greater than the thickness of the steel being cut (for cold-rolled sheet thickness of 9.5 mm, it is sufficient to exceed the flame length by 1.3 mm). When you hear “puffing” or the blue flame seems to be feathery and unstable, it means too much oxygen is being supplied. It is reduced until the entire flame has stabilized, and the inner flame takes the shape of a clear cone.

The inner flame is brought with its very tip to the surface of the steel being processed. It is heated until a puddle of molten glowing metal forms at the point of contact. The tip of the flame must be held still at a distance of about 10 mm from the surface of the steel as shown in the video so that all the heat is concentrated in one area.

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How to use a gas torch. the basics of safe and quality work

Cutting metal with an oxyacetylene torch requires certain precautions and proper sequence of actions. This gas equipment is classified as flammable and explosive.

Preparing and setting up gas cutting equipment

To work safely with a gas torch, it is important not only to correctly select the appropriate set of equipment, but also to connect and configure it correctly. First, the appropriate tubes are connected to the oxygen and acetylene cylinders. Oxygen hoses and containers are usually green, acetylene hoses are red.

At both ends of the hoses, install safety seals (a device that retards back blows of the flame).

The next step is to check that the acetylene supply is working properly. First, close the flow control valve. turn the T-handle back several times. On the cylinder, in its upper part, open the valve. turn it 1 turn of the hand. They do this for security purposes. The pressure of acetylene in the cylinder must not be allowed to exceed 1 atm. in the case of high pressure, this gas becomes unstable and may even spontaneously explode or ignite. To check that the acetylene pressure is adjusted correctly, proceed as follows:

  • The main valve of the vessel is unlocked, then the control valve is opened by turning the knob clockwise. This should be done very slowly, following the readings of the pressure gauge installed at the low pressure outlet. The control valve is opened until the pressure is 0.34-0.54 atm.
  • Then air is blown from the hose. the acetylene valve of the torch is opened until the sound of escaping gas appears. After that, they look at the readings of the low pressure gauge. During purging, the pressure value must be stable (if not, then make sure that the regulator is installed correctly).
  • The valve on the torch is closed.

They check and adjust the oxygen supply. turn off the regulator of its supply (twist it down), and then adjust the pressure. To reduce the oxygen supply, turn the pressure gauge knob a few turns back. Then follow the sequence of the following steps:

  • On the oxygen cylinder, the main valve is fully unlocked. It is double-seated and in the case of its partial opening due to high pressure in the cylinder (150 atm) oxygen escapes around the sealing ring of the valve stem connection.
  • Slowly open the flow regulator, following the readings of the pressure gauge installed at the low pressure outlet, until the oxygen pressure is set within 1.7-2.7 atm.
  • The atmosphere is blown out of the hose. the oxygen valve is opened on the torch. The cutter has 2 valves for oxygen: one closer to the hose, controls the supply to the chamber, where oxygen is mixed with acetylene to heat the steel (combustion of the mixture), as well as to supply it to the oxygen nozzle for cutting; the other is located further away and supplies oxygen to a separate cutting nozzle (until this valve is open or the special cutting lever is released, oxygen should not come out of the cutting nozzle). First, the first valve is opened. it is turned several times to ensure sufficient oxygen supply for both functions. After that, the second (front) valve is slightly opened. for a while until the hose is cleaned (3-5 s for a 7.5 m tube).
  • The front valve is closed.

Preparation of the place and conditions for safe and comfortable work

To ensure safe work using a gas torch, the following rules and recommendations must be followed:

  • To do the work, choose only a place in an ideally ventilated room or in the open air.
  • Can be cut away from flammable substances and materials.
  • The floor in the room must be concrete or earthen.
  • The surface of the ground or concrete must be free of any foreign objects and materials within a radius of at least 5 m, since sparks from the metal being cut fly up several meters and can set fire to dry rags, shavings, paper, dried plants or leaves.
  • Place the metal to be cut on a suitable support to use the torch at a comfortable working height. For these purposes, it is best to use a steel table.
  • Do not allow the flame to touch concrete (especially if it is fresh). this will cause its expansion and subsequent intense cracking with small fragments of concrete flying out of it.
  • It is strictly forbidden to use flammable surfaces as workers, or on which flammable, explosive materials are spilled.
  • The place of the metal cut is marked as shown in the video.

Cutting steel with a gas torch

The handle of the gas cutting valve is slowly released downward. a stream of oxygen is supplied, igniting the molten metal. If a violent reaction immediately begins to occur, then the steel caught fire and you can continue to gradually increase the oxygen pressure until its jet cuts through the material. When the reaction does not take place, the metal is not heated enough to ignite in a stream of oxygen. It is necessary to add oxygen to the heating flame and allow it to heat up the steel.

When the oxygen jet begins to cut, the cutter head is slowly moved along the cut line. At the same time, almost all processing products (molten slag, sparks) are blown away by a jet to the rear side of the cutting zone, as shown in the video. If this flow comes back or slows down, then reduce the speed of the torch or stop it and warm up the material even more (it is better to work very slowly than trying to cut too fast). Cutting continues until the intended cutting or separation of the metal is completed.

What to look for when choosing a gas torch

The selection of a quality tool directly depends on the result. If some parameters are neglected, certain properties of the torch are lost and safety parameters are reduced. Propane and oxygen are explosive substances that require compliance with certain requirements during operation:

  • The handle is made of aluminum alloys, plastic is used with cheaper tools, melts over time, loses its shape.
  • The brass nipple will last longer than the aluminum structure, as it has a greater resource for deformation.
  • The valves must be rotated with little effort to stop the process in the event of a non-standard situation. Recommended valve size. at least 4 cm.
  • The most reliable spindles are made of stainless steel, capable of withstanding up to 1500 cycles without replacement, brass ones do not withstand such a service life. Combined spindles with a favorable price-performance ratio are the most suitable option.
  • The torch design should be collapsible and maintenance is performed to extend the life. Mouthpiece material. copper.

Valve Type Oxygen Propane Cutter

It is necessary to pay attention to the availability of repair kits, spare parts for the torch. If they are not available for free sale, problems may arise when making repairs.

How to use a propane oxygen torch

The operation of a propane. oxygen torch requires compliance with certain rules. Before using equipment with an oxygen, propane torch, it is important to familiarize yourself with the following requirements:

  • Compliance with safety precautions is not neglected, it is important to use a protective mask or specialized goggles. Also, the operator’s clothing must be made of fireproof material.
  • Flame from the torch must be diverted from the gas hoses by the opposite side.
  • The location of gas cylinders is not allowed at a distance closer than five meters to the place of direct work.
  • The dissection is carried out in the open air, or in a room with good ventilation.
properly, cutter

Prolonged downtime of equipment requires preventive maintenance before resuming work. Before starting the test, the propane hose is disconnected, gas pressure is applied. The injector is checked with a finger at the hole, if suction occurs, then the equipment is in good condition.

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Surface and shape cutting

In some situations, it may be necessary to emboss a surface by cutting a groove in the sheet. If it is decided to use a similar cutting method, then the heating of the metal will be provided not only by one flame of the torch. The molten slag will also contribute. As it becomes liquid, it will spread over the entire surface, which will lead to heating of the lower layers of the metal.

The first stage in the implementation of surface cutting is the heating of the selected area to the ignition temperature. After starting the supply of cutting oxygen, you will create a metal burning zone, and thanks to the uniform movement of the cutter, the cut line will get a clean edge. The operation itself must be performed in such a way that the cutter is at an angle of 70-80 degrees in relation to the sheet. When cutting oxygen begins to flow, the cutter is positioned so that it forms an angle of 17-45 degrees from the work surface.

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To create grooves of suitable dimensions, it is necessary to change the cutting speed: to obtain a greater depth, the speed increases, and for a smaller one, it decreases. To create more depth, the angle of inclination of the mouthpiece must be increased, cutting must be done at a slow pace, while the oxygen pressure must also be increased. The width of the groove can be influenced by using the correct diameter of the cutting oxygen jet. It should be borne in mind that the difference between the depth of the groove and its width must be up to 6 times. over, the latter should have an advantage. Otherwise, you may encounter such an unpleasant phenomenon as the appearance of sunsets on the surface.

Preparation for work

Before starting gas cutting, it is necessary to inspect the device to make sure that the propane torch is in working order. Next, you need to perform the following operations:

  • Preparing the cutting machine begins with connecting the hoses to it. Even before attaching the sleeve, it is purged with gas. this will remove debris and dirt from it.
  • The oxygen hose must be connected to a right-hand threaded fitting, a nipple and a nut are used for this purpose. As for the hose through which the propane will flow, it is attached to the fitting with a left-hand thread. Before connecting the gas hose, it is imperative to find out if there is a suction in the cutter channels. This task can be solved by connecting the oxygen hose to the oxygen fitting, while making sure that the gas fitting remains free.
  • Next, you need to set the oxygen supply level to 5 atmospheres, after which you need to open the valves that regulate the flow of gas and oxygen. Touch the free fitting with your finger. this way you will know if there is an air leak. If it is absent, you will have to clean the injector and blow out the cutter channels.
  • After that, you need to make sure that the detachable connections are sealed. If it is possible to identify a leak, fix it by tightening the nuts or replacing the seals. You should also make sure that the mountings of the gas reducers are sufficiently tight, whether the pressure gauges are in working order.
properly, cutter

Precautions

Cutting metal with gas involves some risk, so you must strictly adhere to safety rules. Let’s start with protective clothing, which should include: a fireproof suit and arm protectors with the same impregnation; a welder’s mask made of non-combustible plastic with a headgear; work shoes with high sides. It is also recommended to wear a respirator. Why breathe smoke and dust? All these measures were not invented by chance, and should not be neglected. For example, a situation may arise when thick metal is not immediately blown through, and molten splashes will fall on you.

In the process, do not forget to follow the indication of the reducers on the cylinders. Remember not to start cutting if the hoses are cracked, ripped, or seated. Some craftsmen connect the joints with a tube made of aluminum or brass. However, it’s best not to risk it. Please note that iron pipes cannot be used for this purpose categorically, since iron can give a spark.

The most important thing to know when working with torches is that propane is flammable, while oxygen is oil. If oxygen comes into contact with any oil, an explosion will occur. To avoid disaster, do not touch the oxygen cylinder while wearing oil-stained gloves or clothing. Do not leave oiled rags nearby.

Remember that the cylinders must be located 10 m from the workplace and 5 m from each other. All gas from the cylinder can not be spent in any way.

Sometimes in the process of work, emergency situations arise. Don’t get lost. For example, if your oxygen hose falls off the fitting or breaks off during cutting, do not be alarmed. Usually, fear arises from the fact that it happens unexpectedly and loudly. It is necessary to immediately shut off the propane supply on the torch, then close both cylinders. It happens that when lighting the flame and adjusting the torch, the flame suddenly disappears, emitting a popping sound. Just close the torch valves and reignite the flame.

Before starting work, performers are required to undergo instructions with an entry in a special journal; only persons who have passed tests on knowledge of the theory of the process and the practical execution of cutting are allowed to work.

Workplace preparation

For safe work in oxyfuel cutting of metals, it is necessary not only to comply with safety requirements, but also to competently prepare and organize the workplace, sometimes called fasting. In addition to protective equipment, it must be equipped with:

  • a set of purchased equipment used to cut metal;
  • tools that are used for marking and measuring (ordinary ruler, tape measure, square, special pencil);
  • a special lighter, usually supplied with the rest of the equipment (the use of matches or ordinary lighters is prohibited).

A work station used for gas cutting metals should be located either outdoors or in a workshop or workshop equipped with well-ventilated ventilation. In this case, the floor, according to fire safety requirements, must be earthen or made of concrete. You should also carefully monitor that there are no flammable and flammable materials and products near the working place of the gas cutter. Within a radius of 5 meters from the metal cutting site, the floor or ground is cleared of debris, rags, dry grass and any other objects that could potentially catch fire.

Necessary equipment

To cut metal with gas, you must have one cylinder of propane and one oxygen, high pressure hoses (oxygen), the cutter itself and the mouthpiece of the required size. Each cylinder must be equipped with a reducer to regulate the gas supply. Please note that the thread on the propane cylinder is reversed, so it is impossible to screw another reducer onto it.

The design of gas equipment for cutting metal from different manufacturers differs slightly. Usually all of them have 3 valves: the first is for the propane supply, followed by the regulating oxygen valve, and after the cutting oxygen valve. Most often, oxygen valves are blue, the same that open propane, red or yellow.

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The metal is cut using a jet of hot flame that is generated by the cutter. During the operation of the apparatus in a special mixing chamber, propane combines with oxygen, forming a combustible mixture.

The propane cutter can cut metal up to 300 mm thick. Many parts of this device are replaceable, so the device, in the event of a breakdown, can be quickly repaired right at the workplace.

It is very important to choose the right mouthpiece. When choosing it, one should proceed from the thickness of the metal. If the object to be cut consists of parts of different thickness, which varies from 6 to 300 mm, you will need several mouthpieces with internal numbers from 1 to 2 and external numbers from 1 to 5.

Surface and shape cutting

Sometimes it becomes necessary to cut through the metal not through and through, but only to create a relief on the surface by cutting grooves on the sheet. With this method of cutting, the metal will be heated not only by the flame of the torch. The molten slag will also serve as a heat source. Spreading, it will heat the lower layers of the metal.

Surface cutting, like conventional cutting, begins with the desired area warming up to the ignition temperature. By turning on the cutting oxygen, you will create a metal burning center, and by moving the cutter evenly, you will ensure the stripping process along the specified mowing line of the cut. In this case, the cutter must be positioned at an angle of 70-80 ° to the sheet. When supplying cutting oxygen, tilt the torch, creating an angle of 17-45 °.

Adjust the dimensions of the groove (its depth and width) with the cutting speed: increasing the speed, decreasing the size of the groove and vice versa. The depth of the cut will increase if the angle of inclination of the mouthpiece increases, if the cutting speed decreases and the oxygen pressure increases (of course, the cutting). The width of the groove is controlled by the diameter of the cutting oxygen jet. Remember that the depth of the groove should be about 6 times less than its width, otherwise sunsets will appear on the surface.

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You can cut a figured hole in the metal as follows. First, we outline a contour on the sheet (when marking a circle or flanges, the center of the circle should also be noted). Hole punching should be done prior to cutting. It is always necessary to start cutting with a straight line, this will help to get a clean cut on the curves. You can start cutting the rectangle anywhere except at the corners. Last but not least, the outer contour should be cut. This will help to cut the part with the smallest deviations from the intended contours.

How to properly cut metal with an oxygen-propane cutter?

Compared to gas welding, gas cutting requires much less skill from a person. Therefore, mastering a gas torch is not that difficult. It is enough to understand how to do it correctly. The most widespread in our time are propane cutters. They use propane and oxygen together, since their mixture gives the highest combustion temperature.

The propane cutter is designed for manual separation oxyfuel cutting of carbon and low-alloy steels using propane.

Preparation for work

Before starting work, it is imperative to inspect the device to make sure that the torch is fully functional. Then follow these steps:

  • The first step is to connect the hoses to the cutting machine. Before attaching the sleeve, you need to purge it with gas to remove any debris or dirt that has got there. The oxygen hose is attached to the right-hand thread with a nipple and nut, the second (for propane) hose to the left-hand thread. Remember to check the torch passages for leaks before attaching the gas hose. To do this, connect the oxygen hose to the oxygen connection, and the gas connection must remain free. Set the oxygen supply to 5 atmospheres and open the gas and oxygen valves. Feel the free fitting with your finger to see if air is leaking. If not, clean the injector and blow out the torch passages.
  • Next, check the detachable connections for leaks. If you find a leak, tighten the nuts or change the seals.
  • Do not forget to check how tight the mountings of the gas reducers are and whether the pressure gauges are in good working order.

Advantages and disadvantages

The advantages of cutting metal with propane over other methods are obvious:

Assembly diagram of a hand torch for cutting steel.

  • Gas cutting is used when it is necessary to cut rather thick metal or cut something according to templates, when a curved cut is required, which simply cannot be done with the same angle grinder. A gas cutter is indispensable if there is a need to cut a disc out of thick metal or punch a blind hole 20-50 mm.
  • Light weight and ease of use of the torch is another indisputable advantage. Those who have worked with gasoline counterparts know how heavy, clumsy and noisy they are, vibrate strongly, forcing the operator to make significant efforts during work. Gas models are devoid of all these disadvantages.
  • In addition, cutting metal with gas allows you to work 2 times faster than when using a device with a gasoline engine.
  • Propane is much cheaper not only than gasoline, but also other gases. Therefore, it is beneficial to use it for large volumes of work, for example, when cutting steel for scrap.
  • Propane cut edges are slightly worse than acetylene cutters. However, the cut is much cleaner than with gasoline burners or an angle grinder.

How to properly use an oxygen acetylene torch for cutting

The only drawback of gas cutters (including propane ones) can be considered the limited Spectra metals that can be cut with their help. They can only handle low and medium carbon steels, as well as ductile iron.

Oxygen-propane soldering and welding plant.

It is impossible to cut high-carbon steels with gas, because their melting point is quite close to the flame temperature. As a result, the dross is not ejected in the form of a pillar of sparks from the back of the sheet, but is mixed with molten metal along the edges of the cut. This prevents oxygen from reaching deep into the metal to burn through. When cutting cast iron, the process is interfered with by the shape of the grains and the graphite between them. (An exception is ductile iron). Aluminum, copper and their alloys are also not amenable to flame cutting.

It should be recalled that grades from 08 to 20G belong to low-carbon steels, grades from 30 to 50G2 to medium-carbon steels. In the designations of grades of carbon steels, the letter U is always put in front.

Getting started

We set 5 atmospheres on the oxygen reducer, and 0.5 on the gas reducer. (Typically a gas to oxygen ratio of 1:10.) All torch valves should be closed.

To work with a cutter, set 5 atmospheres on the gearbox, and 0.5 atmospheres on the gas.

Take the cutter, first open the propane a little (by a quarter or a little more), set it on fire. We rest the nozzle of the cutter against the metal (at an angle) and slowly open the regulating oxygen (do not confuse it with the cutting one). We adjust these valves one by one to achieve the flame strength we need. When adjusting, we open alternately gas, oxygen, gas, oxygen. The strength (or length) of the flame is selected with the calculation of the thickness of the metal. The thicker the sheet, the stronger the flame and the higher the oxygen consumption with propane. When the flame is adjusted (it turns blue and crown), metal can be cut.

properly, cutter

The nozzle is brought to the edge of the metal, it is kept 5 mm from the object being cut at an angle of 90 °. If a sheet or product needs to be cut in the middle, the metal should be heated up from the point from which the cut will go. We heat the upper edge up to 1000-1300 °, depending on the metal (up to the temperature of its ignition). Visually, it looks as if the surface has started to “get wet” a little. Warming up takes literally a few seconds (up to 10). When the metal ignites, open the cutting oxygen valve, and a powerful narrowly directed jet is applied to the sheet.

The valve of the torch should be opened very slowly, then the oxygen will ignite from the heated metal on its own, which will avoid a blowback of the flame, accompanied by a pop. We slowly move the oxygen stream along the specified mowing line. In this case, it is very important to choose the right angle of inclination. It should be at first 90 °, then have a slight deviation of 5-6 ° in the direction opposite to the cutting direction. However, if the thickness of the metal exceeds 95 mm, a deviation of 7-10 ° can be allowed. When the metal has already been cut by 15-20 mm, it is necessary to change the angle of inclination by 20-30 °.

Nuances of metal cutting

Flow diagram of the separation oxy-fuel cutting process.

You need to cut the metal at the right speed. The optimal speed can be determined visually by how the sparks fly away. A stream of sparks at the correct speed flies out at an angle of approximately 88-90 ° to the cut surface. If the sparks are flying in the opposite direction of the torch, the cutting speed is too slow. If the angle of flow of sparks is less than 85 °, this signals an overspeed.

When working, it is always necessary to be guided by how thick the metal is. If over 60 mm, it is better to arrange the sheets at an angle to ensure the drainage of slags, and do the job as accurately as possible.

Cutting thick metal has its own characteristics. You cannot move the torch before the metal has been cut to its full thickness. By the end of the cutting process, it is necessary to smoothly reduce the advance speed and make the angle of inclination of the torch more by 10-15 °. It is not recommended to stop during the cutting process. If work is interrupted for any reason, do not continue cutting from the point at which you stopped. It is necessary to start cutting again and only in a new place.

After finishing cutting, first shut off the cutting oxygen, then turn off the regulating oxygen, last turn off the propane.