Cutting metal with a gas cutter. Advantages and disadvantages

A gas cutter is required? What kind of equipment is necessary for metal gas cutting

Gas cutting appears to be a simpler process than gas welding, and therefore, even the unskilled can cope with it. For this reason, almost any of us can learn to use a gas torch. The main thing here is to learn the essence of gas cutting technology. Propane torches are increasingly being used in modern conditions. Working with them requires the use of propane and oxygen at the same time, because the combination of such substances provides the maximum combustion temperature.

Gas cutting and welding of metals has many advantages, but we are only interested in cutting that has these advantages:

  • It is in demand when metal of great thickness is cut or stenciled cutting is needed, and an angle grinder cannot handle curved areas.
  • The gas counterpart is much more convenient to work with, has a low weight, operates twice as fast as equipment with a gasoline engine.
  • Propane is less expensive than acetylene and gasoline, so its use is more cost-effective.
  • Cutting edge is much narrower and structure is cleaner than with an angle grinder or gasoline-powered equipment.

The disadvantages are the narrower range of metals that can be treated in a similar way.

Equipment for gas cutting

To perform this type of work, you need to have the following equipment:

The gas cutting torch is the most important piece of equipment for cutting metal. Most torches today are self-injected. They can cut metal up to 300 mm thick. The structure of the torch is similar to a gas torch. But unlike it, it has an additional tube for oxygen supply to the injector chamber. In this chamber, oxygen is mixed with combustible gas. There is also an additional valve on the torch for oxygen. It is used to regulate the oxygen supply.

Propane is used as a combustible gas for cutting metals. You can use acetylene, but it is very expensive for cutting. Propane has a lower combustion temperature than acetylene, but it is still enough to cut through structural steels.

cutting, metal, cutter, advantages

Reduces the pressure value of oxygen or combustible gas. Cylinder, including pressure gauge, is used for adjusting gas pressure while gas cutting. There is a different reducer for oxygen and a different one for combustible gas. It is impossible to mix them up by putting them on a wrong bottle, as they have different threads.

Fitted on pressure reducer. Manometer serves to control the regulated pressure of oxygen or combustible gas.

Hoses for gas cutting, they are rubber hoses made of thick rubber. Combustible gas hoses should not be used with oxygen hoses, as they are designed for different operating pressures. They also have different threads.

Safety gates.

Protects welding hoses, also protects cylinders from backfire. Keeps flames from passing through the hoses and into the cylinder. Installed between cylinder and torch on each hose.

Instructions for cutting metal

It is important to connect and prepare the torch properly. Cylinders are connected with tubes with gates at the ends. Next, gas supply is checked (if it is oxygen-propane metal cutting). valve on cylinder is closed, valve is opened. Then, watching the manometer, slowly open the valve. Pressure must be 0,35-0,55 atm. Then you need to blow through the hose. open the valve. Gas starts to come out with a characteristic sound. When the pressure gauge shows a stable pressure, the valve closes.

Next step. oxygen supply check and pressure adjustment. First you open the valve on the cylinder, then you open the regulator (flow pressure 1,7-2,7 atm). To blow out the hose, open the oxygen valves on the cutting torch. There are two: one for feeding into the nozzle and one for the mixture. First open the first valve, then open the second valve (for 3-5 seconds).

Attention! Before igniting the valve, make sure there are no leaks in the connections, no children playing nearby and no animals walking around.

cutting, metal, cutter, advantages

The gas valve is opened first, so that the oxygen, which was left in the mixer after checking. turn the valve until you hear gas go out. the lighter placed in front of the cutter should touch the nozzle. After actuating the spark lever, ignite the gas.

Open the oxygen valve immediately. sufficient volume is indicated by the change of color of the flame to blue. oxygen must be applied to make the torch grow in size. Gas and oxygen pressure when cutting metal depends entirely on the thickness of the workpiece.

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Important! If the flame is unstable and “sniffles”, there is too much oxygen. Volume must be reduced so that the flame is in the shape of a cone.

In gas metal cutting technology, the flame was brought to the material by the tip, heating the surface. When the molten metal appears, start feeding the oxygen that ignites it. The jet increases as long as the material is cut through. The nozzle moves along the cutting line at the same time. Sparks and slag are removed by jetting.

The optimum cutting speed is determined by the sparks. they should fly away at an angle of 85-90 o. If the angle is smaller, the speed needs to be reduced. If the billet is thick, it must be placed at an angle to allow the slag to drain off. It is not advisable to stop before the process is complete. When you finish, first shut off the oxygen, then the gas.

Types of metal cutting with gas

There are several types of oxy-fuel cutting. Scientists and engineers have developed these methods based on application-specific conditions. The following cutting methods are the most common:

  • Propane. This is a fairly popular method for titanium, low alloy steels, and low carbon steels. Not suitable for carbon and high-carbon steels. Propane can be replaced with methane or acetylene for better performance and energy efficiency.
  • Air-arc cutting. In addition to the combustion of the material in the oxygen stream, an electric arc is excited between the workpiece and the electrode integrated in the torch. It melts the metal in the area of the cutting line, and the gas stream carries away the rest. The method does not permit cutting of thicker workpieces, but makes it possible to make cuts of greater widths. This is very useful for shaped cuts and considerably reduces the laboriousness of the operation.
  • Oxygen-fluxing. With this method, flux powder is applied to the work area. This component is involved in physical and chemical processes and provides increased plasticity and suppleness of the material during cutting. The method is applicable to cutting of alloys, on the surface of which strong and heat-resistant oxide films are formed. Fluxing removes them by shifting the temperature balance to a higher zone. This method is especially effective for cast iron, copper, bronze and brass items, workpieces with a high degree of slagging and for reinforced concrete.
  • Spearhead. It is used for disassembling of metal structures, technological waste, cutting of massive large-sized blanks. A stream of oxygen flows through a thin steel tube. the gas lance. The lance is a consumable; it burns off during the process, increasing the temperature and efficiency of the main reaction and allowing for additional concentration of the cutting torch. This results in a significantly higher cutting speed.

Technologically, the gas-oxygen cutting process requires the torch to be driven manually by the torch cutter.

Gas supply is controlled by one common or two separate shutoff valves. The use of split valves allows fine-tuning of the mixture and a quick readjustment of the equipment for a different type of work.

Torch handle has three nozzles with connectors. It feeds oxygen, propane (or acetylene) and a coolant. The oxygen pressure is set on the cylinder pressure reducer and can reach 12 atmospheres.

After performing the ignition, oxygen is fed into the torch torch torch. The combustion of propane heats the surface of the workpiece to such a temperature that a chemical reaction begins to oxidize it. It goes so intensely that the workpiece is burned through by the jet of cutting oxygen, and the gas stream carries burnt metal particles into the cut.

How to cut metal with a gas cutter: equipment

Once upon a time, the autogen was a favorite tool of safecrackers. criminals who used to break safes. It is clear that those safes were of the old type. heavy armored brunds. Bear-cutters were professionals of the highest skill. true masters of metalwork. These days things are different: safes are different and safes have become hackers. Modern metalwork is the widest field of professional activity. It includes, among other things, metal cutting, which is performed by a gas cutter, which is the same autogenous by nature.

If metal sheets and profiles of small thickness can be cut with simple mechanical tools, such as special scissors for metal, the metal with thick edges can only be cut with a gas cutter, without it with a massive workpiece. nowhere.

There is a wide variety of models with different designs, sizes, etc.д. But one way or another, the principle is exactly the same.

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What are cutting torches and what are they

The gas cutting torches are designed for cutting rolled metal products and disassembling metal structures. The principle of operation of a metal cutting torch is quite simple. at the end of the torch gas burns, creating a zone of high temperature, exceeding the melting temperature of the metal. The gas is either fed through a hose from a portable cylinder built into the handle or from an external cylinder with a hose. For oxidation of combustible gas air oxygen can be used, in other designs of oxygen torches gas is fed from a separate cylinder on a separate hose.

There are many varieties of gas cutters and torches. Existing torch types are classified according to the following criteria:

In addition, there are ultra-portable mini type gas torches, the power of which, however, allows you to cut a few millimeters of steel or copper sheet. Such a gas torch is ignited from a match or from a built-in piezoelectric element.

Injector torch for manual oxygen cutting not only does not fit in your. but also requires an impressive cart to transport its cylinders. Stationary cutting torches for sheet metal are complex automated industrial plants with an area of dozens of square meters, the gas is supplied to them by a stationary pipeline from large gas holders.

Features of use

Steel materials with high carbon content should not be cut with a gas cutter. The reason is the high melting temperature, close to the parameter of the hearth. Instead of dross being ejected by the nozzle, the material reacts with the edges and the result is that the oxygen is no longer available, and the connection cannot be machined.

Work with cast iron may cause some difficulties, such as the presence of graphite, the shape of grain. Propane gas cutting is also not used when working with copper, aluminum and other easily melting steels.

Construction of gas cutter

The design of a cutting torch is quite simple. The main units are:

The barrel, in turn, consists of the ejector, inlets for connecting hoses, nipples, shutoff. regulating and connecting fittings.

All units, despite their different performance and other characteristics, have a similar principle of operation. Combustible gas and oxygen are fed into the mixing chamber and then, under pressure, flow out through the working nozzle. Speed of gas flow and mixing ratio are controlled by two independent valves at the device inlet. This determines the intensity of the flame and its temperature.

The torch hits the metal and quickly heats it to its melting point. Part of the metal evaporates and is carried away with the combustion products into the atmosphere, some of it oxidizes and turns into slag, and some of it drips. A cut is made in the metal. If you move the torch smoothly along the marked line, the heating zone will move and the cut will increase until the desired part of the workpiece is cut.

Equipment required

To perform various steel processing tasks, it is necessary to prepare equipment, appropriate tools. Operation is carried out with the help of:

Safety requires a control valve on each cylinder. Propane cylinder has a return thread, so an additional reducer is not possible. The equipment has similar designs for both home use and production purposes. Before cutting metal, it is necessary to check the functioning, availability of all adjusting elements.

Cutting nozzles for hand torches and cutting inserts of torches (PROPAN/Natural gas/MARR-GAS)

HANDHELD TORCH/BURNER SERIES PL-RC L-PN PB-K/PMY PNME GRICUT
1230 PMYE 123 PMY 1280 PMYE 2280 PMYE 8281 8281 PMYE
Cutting insert model
Cutting insert MINITHERM 2207-PMY (up to 25 mm)
STARLET 1211-PMY cutting insert (up to 100 mm)
STARLET 1711-PMY cutting insert (up to 100 mm)
STARLET 8702-A/PMYE (up to 100 mm) cutting insert
STARLET 8711-A/PMYE cutting insert (up to 100 mm)
STAR 1230-PMY cutter insert (up to 200 mm)
STAR 1730-PMY cutter insert (up to 200 mm)
STAR 1730-F cutting insert (up to 200 mm)
STAR 8730-A/PMY cutter insert (up to 200 mm)
STAR 9230-A/PMY cutting insert (up to 200 mm)
Handheld torch model
PROFICUT hand torch.L/H/HB.A/PMYE
STARCUT 1222-PMYE hand torch
STARCUT 1622-PMY hand torch
STARCUT 2222-PMYE hand torch
STARCUT 2622-PMYE hand torch
STARCUT 8622-A/PMYE hand torch
STARCUT 9622-A/PMYE hand torch
STARCUT 8222-A/PMYE hand torch
STARCUT 9222-A/PMYE hand torch
ESSEN 1216-PMY handheld torch
ESSEN 1625-PMY hand torch
ESSEN 8216-A/PMY hand torch
ESSEN 8625-A/PMYE hand torch
HAND TORCH / TORCH SERIES Acetylene Propane/Pyr. gas/Marr-gas/ethylene
FD-A Block-A FAG AGNM FD-PM Block-PM Block-YF
STARCUT 1622-A hand torch
STARCUT 3622-A hand torch
STARCUT 1622-PMYE hand torch
STARCUT 2628-A hand torch
STARCUT 7628-A hand torch
STARCUT 2622-PMYE Handheld Cutter
STARCUT 8622-A/PMYE hand torch
STARCUT 9622-A/PMYE hand torch
ESSEN 8625-A/PMYE hand torch
ESSEN 9625-A/PMYE hand torch
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Equipment

The main equipment for gas cutting is the torch. It comes with a welding and fusion nozzle.

Thanks to the torch, you can control the dosage of the gas mixture and oxygen. Also with the help of this equipment is carried out ignition of combustible mixture, supply of flame to the place of treatment.

Cutter consists of two units: cutting unit and preheating unit. The first one is represented by an oxygen outlet tube, a valve and an internal nozzle.

Heating unit includes valves that are designed to regulate the pressure of the gas mixture and oxygen. There is also a feeding tube, an external view nozzle, a mixing chamber and an injector cell.

Torches can be manual or machine torches. the latter are stationary, so for the repair works it is preferable to use manual cutting insert STAR 1730-PMY (up to 200 mm).

The following gas cutting equipment is additionally used:

  • Reducer. designed to reduce pressure;
  • pressure changing device;
  • A steel gas and oxygen cylinder;
  • connecting hoses.

Before using the equipment it is important to check that it is in good working order to prevent the cylinder or gearbox from exploding. Torch is pre-blown with oxygen.

Popular services on the market

If you need to cut metal, the easiest way. to hire a master or a specialist who will provide you with the necessary services. After all, not everyone at home in the garage is a cutter with two cylinders of oxygen and a heater.

over, it is very dangerous to work with such equipment without experience! If you do not know how, then it is better not to take on this job. leave the work to professionals!

For example, the usual sheet cutting is the cheapest. Pipe cutting. is much more expensive, because such work uses additional overlays!

Cutting deep, on the other hand, is expensive because it involves the use of expensive equipment.

IMPORTANT: Metal slitting. machines, lines, units

over, if such work is performed “on-site”, it will be very expensive. Cars that can transport cutting stations need to be retrofitted.

Well, the gas cutting of sheet metal can be performed even by an ordinary gas soldering iron. If you are using aluminum or copper, then it should be quite sufficient for such work.

In some cases, you can use gas welding. Except that instead of carbon dioxide is fed propane, acetylene or butylene (not every gas welder supports the use of such gas, be careful)!

By the way, if you need to perform not cutting, but cutting, then in some cases it will be much easier and cheaper to use just a knife to cut metal, rather than a gas torch. You can learn more about this directly from the master, to whom you want to entrust the work.

Now many companies offer gas cutting of metal with the departure.

Here it is, judged by the following parameters:

By the way, it is recommended to buy their own gas cylinders! Many companies sell it at too high a price (about 1000 per cylinder of acetylene, even though its market price is only 1000).

Also takes into account how much time the work will require. On average, an hour of work is paid to the master at about 300. Here you can calculate in advance how much the metal cutting services will cost you!

Well and finally we should talk about those cases where the low-quality work is done. Very often many people use propane or propylene instead of acetylene. its cheap analogue. Or they use cheaper cutters than they were declared.

The P1-01 has twin nozzle with gold mount (golden color), but the P2-01 has steel mount (has black or copper color).

By the way, the torch P1-01 is not so expensive, so you can even buy it! The average per piece. Well, of course, it will be necessary to buy two cylinders. with oxygen and a heater, well and a carrier bag.

On average the whole kit will cost you about 3000, no more. It is sufficient for three hours of metal cutting. For household needs. it is more than enough.

And when working with a gas cutter, be sure to follow the safety rules! And this is the use of a protective mask, overalls and gloves. Gloves are a must!

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