Is it possible to cut metal by welding

Mechanical methods

The classification of mechanical cutting methods is usually based on the answer to the question: how to cut metal?
Cutting with a hacksaw and scissors for metal

Cutting with scissors: a) cutting the sheet into strips; b) cutting with leaf cutters.
Cutting a round shape: c) wrong; d) correct

At home, metal is usually cut with an ordinary hacksaw. This process is quite laborious. It is greatly simplified if you have a mechanical hacksaw at your disposal.

Unlike hacksaws, there are many types of metal scissors:

  • Hand shears allow you to cut relatively thin sheet metal. They allow you to do this quickly and accurately by following the cut line correctly. There are several types of hand scissors: finger, power, chair, lever, for curved cutting.
  • Slotted scissors carry out both straight and curved cutting. They allow you to cut metal in confined spaces while maintaining a high quality cut. Powered by an electric motor.
  • Guillotine shears can cut metal with high precision. The main advantages are the absence of defects, high cutting accuracy, the safety of the outer coating of the material being cut.

Types of guillotine shears:

Hand scissors can cut a relatively thin sheet of metal.

  • Hand scissors. The main disadvantage is that the developed force is not enough for cutting if the metal is very strong.
  • Mechanical scissors. Powered by an electric motor, so the productivity is significantly higher than that of manual guillotines.
  • Hydraulically driven shears. Provide very high accuracy of work. In addition, they can be equipped with a CNC, which makes it possible to significantly increase their productivity by storing typical parameters of cuts in the memory.

Reciprocating and circular saws, angle grinders

Reciprocating saws are similar in principle to a jigsaw. Outwardly, they look like an electric drill, only instead of a drill. a saw pushed forward with a length of 10 to 35 cm, making a reciprocating motion. Usually the saw is powered from the mains, but battery versions are also available.

Reciprocating saws are used for accurate and fast metal cutting.

For different types of work, different types of saw blades are used. They change easily, like drills in an electric drill. The fastening system is reliable and efficient. Knowing what to work with, you can choose the right file. For example, the greater the curvature of the cut, the narrower the canvas should be.

Working with a reciprocating saw requires skill, a steady hand and a good eye.

It is easier to work with circular saws. Their cutting discs are usually made of hard high-alloy alloy or special high-speed steel. Saws are designed for cutting a variety of metal profiles made of a wide variety of metals and alloys, provide a narrow kerf, a small amount of chips.

To choose the right saw, you should pay special attention to the saw blade, in particular to its diameter. The larger it is, the more possibilities the instrument has. After the cut, additional processing is usually required to remove sharp edges. The disadvantages include rather large dimensions and a rather high cost.

Circular saw can cut copper, aluminum and other non-ferrous metals.

Most consumers don’t even know that the “angle grinder” is an angle grinder. The fact is that this miracle of technology comes from an angle grinder, and our people do not like long names. In most cases, an angle grinder equipped with a steel cutting disc perfectly replaces a circular saw for metal, although, as the name suggests, it was originally intended for grinding.

Today, many people use it as a saw, and not for grinding, although a modern angle grinder can be cut, cleaned, polished, etc. over, almost all materials can be cut and grinded. The main thing is that you don’t need to buy various tools. For various materials and works, only different consumables are purchased, and the machine itself only needs one.

Tools and methods for cutting metal

Cutting is one of the most common operations in the processing of metal workpieces.

But here the question immediately arises: how and with what metal is cut?

Metal can be cut mechanically or thermally.

It is customary to distinguish between two main groups of cutting methods:

  • Mechanical. sawing, scissoring, etc.
  • Thermal, based on the use of a jet of any substance. gas, water, etc.

Thermal methods

Cutting methods belonging to this group can be divided into the following types: gas and gas-electric cutting of metals.

In these cutting methods, the metal is heated by a gas (oxygen) flame, and power sources are not used. There are three main ways of such cutting:

Oxygen cutting of metal involves heating it. hot oxygen jet cuts metal and removes oxides that arise there.

  • Oxygen. With this method, the metal in the cut zone burns out in an oxygen jet, and the formed oxides are blown out by it.
  • Oxygen-flux. A flux powder enters the cut area, which facilitates the cutting process due to chemical, thermal and abrasive effects.
  • Oxygen lance. The high temperature is created by the combustion of the so-called spear. a tube through which a stream of oxygen is blown.

The main advantages of these methods:

  • low cost;
  • thick layers of metal can be cut.
  • high metal consumption;
  • low accuracy;
  • the need for additional processing of parts;
  • low cutting speed;
  • large cutting thickness;
  • thermal deformation of metal.

In gas-electric cutting, the metal is heated by a power source, and the melt is removed from the cutting zone by a gas jet. There are two ways to do this:

  • Air arc. liquid metal is removed from the melting zone with a jet of compressed air.
  • Oxygen-arc. the metal heated in the arc flame burns out in the incoming oxygen stream, it is blown out by it.
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It is mainly used to correct defects in welded seams. The main disadvantage is the carburization of the cut site due to the combustion of carbon electrodes.

Plasma cutting is by far the most advanced, fastest and most cost effective way to cut metal.

A very promising and rapidly progressing method. The cut metal is melted by a jet of plasma. ionized gas with a temperature of tens of thousands of degrees. A plasma jet is created in a special device. a plasmatron. from an ordinary electric arc due to its compression and injection of a plasma-forming gas into the reaction zone. Two main processing schemes:

  • Plasma jet cutting. With this method, an arc occurs between the electrode and the tip of the plasmatron. The work piece is not included in the electrical circuit.
  • Plasma arc. an arc occurs between a non-consumable electrode made of a refractory material and the metal being cut. An effective and more commonly used method.

The advantages of plasma cutting compared to gas cutting methods:

  • high cutting speed;
  • versatility of application;
  • the ability to cut with high precision and quality;
  • no need for expensive gases;
  • the ability to cut parts of complex shapes;
  • safety and environmental friendliness.
  • high cost and complexity of equipment and its maintenance;
  • impossibility of cutting workpieces with a thickness of more than 80-100 mm;
  • limited angle of deviation of the cut from perpendicularity;
  • increased noise level.

Cutting Metal With A Stick Welder

The remaining thermal methods, due to a number of reasons, of which the main one is the high complexity and cost of equipment, have not yet become widespread. We will limit ourselves only to their listing:

possible, metal, welding
  • hydro and water jet cutting;
  • laser and gas laser cutting;
  • electrical erosion method;
  • cryogenic cutting.

Summarizing all of the above, we can conclude: there are a lot of methods and types of equipment for cutting metals. It is possible to choose the most suitable methods correctly only by weighing many factors, primarily financial opportunities.

Technological process

It includes several necessary steps: preparation of parts, connecting electrodes, starting the burner and its warming up, making a seam while maintaining the desired temperature mode and moving the burner to the place of a new operation with checking the readiness of the burner itself.

Plasma cutters, can they be used for welding?

Posts: 1 913

Here I watch the programs on the discovery,
plasma cutting equipment is often found.
They are usually used for cutting metal.

I have a question. can they be used for welding ?
After all, the principle of operation of the plasma cutter is
in the use of a jet of hot plasma escaping from the nozzle.
The same principle is used for gas welding. ,
when the wire is melted and the parts are welded with drops of metal.
Can I also use a plasma cutter ?

The advantages are obvious. no gas cylinders required,
and, accordingly, fewer problems with auditing inspections.
I do not know about the cost of the plasma cutter.

Post has probably been edited. Jul 23 2009, 14:53

Posts: 18,604

Portable single-phase inverters for air plasma cutting with contact arc ignition. Suitable for fast cutting without deformation of all conductive materials such as steel, stainless steel, galvanized steel, aluminum, copper, brass, etc. Supplied complete with plasma torch. Features: reduced weight and dimensions Indication of the presence of ignition voltage Automatic cooling of the plasmatron Air pressure indication Thermostat, protection against overloads, overvoltage and undervoltage is equipped with a compressor and therefore does not require connection to an additional source of compressed air Power Max 2.8 kW Voltage 220 V Voltage frequency 50 Hz Number of phases 1 Cutting current Min-Max 5-25 A 25% 20 A Cutting parameters 6 mm Dimensions LxWxH 475x170x340 mm Weight 12.5 kg

Posts: 11,269

Posts: 1 913

I myself saw how they cook gas, acetylene oxygen:
ordinary wire from the chain-link mesh and a burner and nothing else,
by the way, it turns out very neatly.

Post has probably been edited. Jul 23 2009, 16:31

Posts: 7,282
From: Cheboksary

Generally speaking, it is impossible. But if you really want to, then you can

There is even a representative:
Cheboksary,
IE Vasiliev N.I.
428034, Cheboksary, st. T. Krivova, 8/1
Tel./Fax (8352) 40-32-43, 45-56-06
Tel. (903) 346-86-29
The contact person:
Vasiliev Nikolay Ivanovich

But they say that a wagon is always worse than a few narrow specialists. Both in metalworking and in general “in life”.

Post has been editedAdvik. Jul 23 2009, 18:11

Posts: 23,506
From: wounded by the soul

a good plasma cutter is impossible. the plasma torch will blow everything away. that is why it is called a plasma cutter, and not, say, a plasma installation
there are other equipment for plasma welding, but large things are not cooked with plasma, then welding is called microplasma. in fact, it differs from argon-arc welding only by the presence of a two-gas plasmatron, in which argon (or other inert gas) enters the plasma-forming chamber through a swirler at a low flow rate. the second gas (the same argon, but with many times higher consumption) is a protective one and is needed to create an inert “curtain” around the welding zone. tungsten electrode. arc excitation is only non-contact, and an indirect arc is initially excited, subsequently turning into a straight arc (like most modern plasma cutters)
the only advantage over conventional argon-arc welding is that due to the crimping of the arc torch, it gets a needle-like shape, which increases the penetration depth of the metal without additional cutting. combined with low heat input, this significantly reduces the annealing zone.

a little bit wrong, I suppose. during gas welding, it is necessary to warm up the parts to be welded, and the filler material (wire, bar, or just pieces of metal) is fed into the welding zone and, ideally, should melt in the weld pool. since I have not done gas welding, I could be wrong. let the welders fix it
but this is how they cook with argon-arc welding and welding from gas generators. moreover, stainless steel and some other materials can be welded without any additive at all. by self-pressing.
if you just drip drops of filler metal onto the parts, albeit heated ones, then there will be no welding. there must be a bath. a place with a melt. in the welding zone

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Portable single-phase inverters for air plasma cutting with contact arc ignition. Suitable for fast cutting without deformation of all conductive materials such as steel, stainless steel, galvanized steel, aluminum, copper, brass, etc. Supplied complete with plasma torch. Features: reduced weight and dimensions Indication of the presence of ignition voltage Automatic cooling of the plasmatron Air pressure indication Thermostat, protection against overloads, overvoltage and undervoltage is equipped with a compressor and therefore does not require connection to an additional source of compressed air Power Max 2.8 kW Voltage 220 V Voltage frequency 50 Hz Number of phases 1 Cutting current Min-Max 5-25 A 25% 20 A Cutting parameters 6 mm Dimensions LxWxH 475x170x340 mm Weight 12.5 kg

judging by the parameters, the maximum thickness of ferrous metal with a “finishing” cut is not more than 4mm. perhaps less. 6mm. clearly a rough cut, which increases the width of the cut, the number of burrs and decreases the cutting speed. otherwise quite a curious thing. for bodywork and openwork cutting for thin metal.

no way. the very first type of arc welding, if I am not confused (which is quite possible, by the way) is welding with a graphite rod. no additional protection was provided. by the way, sometimes I cook thermocouples with such macar. it comes out pretty well

gas welding is one of the most substandard types of welding. dirty, explosive, the welding area is not protected. do not take
perhaps only a gas generator apparatus of the “League” type for domestic purposes. I just don’t know if they are still being released. the device is simple: a set of metal plates, like in an electric capacitor of variable capacity in old receivers, only larger, is in a tank filled with a solution of either soda or some other chemical. voltage is applied to the plates, respectively, through the water, generously flavored with alkali, the current flows briskly. gaseous oxygen and hydrogen are released on the plates. since there are many plates, the flow is quite decent and there is some excess pressure. through a hole in the upper part of the tank, the gas mixture enters the explosion-proof bubble valve, and then into the burner hose. the same autogen, but the devices that I tried were equipped with tiny burners that you hold like a pencil. almost a piece of jewelry

Generally speaking, it is impossible. But if you really want to, then you can

http://www.multiplaz.ru/
.
But they say that a wagon is always worse than a few narrow specialists. Both in metalworking and in general “in life”.

1) not worth the money that they ask for;
2) go broke on consumables

the rest is a pretty cute toy. almost anything can be cut, including ceramic tiles and glass. however, a toy is also a toy in Africa. yes, and pouring vodka into her insides for welding, my hand does not rise

The difference between argon welding and plasma welding

Argon welding is carried out in an argon atmosphere at normal pressure, the energy density in the arc does not exceed that for simple welding. It’s just that the weld pool is protected from the action of oxygen, and the tungsten electrode is practically not consumed.

Plasma welding is performed with a plasma torch. a plasma arc generator in an atmosphere of increased pressure. This achieves a very high temperature in a narrow plasma column. Unlike an arc of atmospheric pressure, the torch of a plasma arc is almost cylindrical, the pressure on the metal is 5-8 times greater.

Types and features of plasma welding

Plasma welding is a fairly young method of joining parts. Despite the fact that it appeared relatively recently, it has already gained great popularity due to its advantages and capabilities. Let’s consider in more detail what plasma welding is, what it consists of and how it differs from other types of welding.

Tips from professionals

  • before starting the connection of parts, prepare a workplace and a form for the master;
  • check the serviceability of the apparatus and the pressure in the cylinders;
  • plasma welding of aluminum should be carried out at a low current;
  • the plasma torch for welding must be cleaned (blown through) before starting the process;
  • microplasma welding is ideal for beginners to master this technique;
  • plasma welding technology is chosen by the master himself, since both methods have their own advantages.

Comparison of laser welding technology with plasma welding

Laser welding is performed with powerful continuous or pulsed lasers. By focusing the spot on a very small area, it is possible to obtain very high temperatures. The beam of light is not affected by a magnetic field or gas movement, the laser can be easily “fed” into hard-to-reach places. By changing the beam aperture, you can very smoothly adjust the width of the heating zone. The productivity of laser welding is about 50 times higher than that of arc welding. For example, a 20 mm steel sheet is welded at a speed of 100 meters per hour in one pass.

However, laser welding also has disadvantages: low efficiency. due to the significant reflection coefficient (0.1-2%) and the very high price of the equipment. Despite this, there are areas where laser welding is indispensable, for example, in the electronics industry in the manufacture of many devices, especially miniature ones. Therefore, usually the workplace of a laser welder for manual work does not look quite suitable for a construction site or a garage:

Technique and features of the process in all spatial positions

In engineering, we deal with a wide variety of weld arrangements. When welding individual parts, the work is slightly facilitated by the fact that the arrangement can be reduced to horizontal, with the torch located on top.

This is the most advantageous location for welding, but not always technologically feasible. For example, when welding a seam on a ship’s hull, you have to position the burner as you like. you cannot turn the ship in the dock like a toy. Therefore, to protect the bath from spreading beyond the permissible limits, it is necessary to select favorable burner positions.

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For example, when welding a vertical seam, the torch is slightly below the seam and the plasma jet is directed upward. By choosing the angle of inclination and distance to the bath, it is possible to “blow off” the flowing metal upward. This is done dynamically as the seam progresses and requires good manual skill.

Consumable electrode arc cutting

This method allows you to achieve greater accuracy and clarity, and the cut itself comes out narrower than the previous method. For cutting, the same electrodes and the same diameter are used as for welding, while increasing the current strength by 20-30%. Carrying out such work in a domestic environment, you can use simple electrodes, but to improve the work process, it is recommended to purchase special electrodes with a special coating.

There are two types of coating formulations. First: manganese ore (98%) and potash (2%). Second: manganese ore (94%), kaolin (3%), marble (3%). Thanks to this coating, the stability of the arc increases, the inner core melts more slowly and is isolated from the cut walls. The molten metal is oxidized due to the special components contained in the coating, this allows you to speed up the cutting process.

The production of the above-described electrodes is carried out from wire with a diameter of 3 to 12 mm and a length of up to 300 mm. The thickness of the special coating should be 1-1.5 mm. The calculation of the current strength is made from the following ratio: 55-65 A per 1 mm of the diameter of the electrode used.

Arc cutting with a non-consumable electrode

With this method, work is carried out both on alternating and direct current of direct polarity. The current strength should be 400-800 A. In this case, carbon and graphite electrodes are used.

This method is not widely used. It is used for parsing large-sized metal scrap, making holes and burning out rivets, as well as for dismantling unnecessary metal structures.

The cut is carried out by melting the metal in the required area, and not by burning it. Thanks to this quality, it becomes possible to work with materials that cannot be cut by gas, such as cast iron or high alloy steels.

This method does not differ in high accuracy of work: the width of the cut itself is large, and the edges remain uneven. If you use electrodes with a rectangular cross-section, then it will be possible to slightly improve the result of the work.

Features of electric arc metal cutting

Arc cutting is usually done by hand. For work, it is recommended to use steel electrodes with a thick refractory coating, but tungsten and carbon electrodes can also be used.

For this method of cutting metal, you do not need to have special equipment. Work can be carried out in hard-to-reach places and in any spatial position of the structure.

However, when separating metal with an electric arc, it is not possible to achieve high quality. It is impossible to ensure the evenness of the edges of the parts and there is a large amount of slag precipitation. Therefore, for the further use of the obtained metal parts, their mechanical processing is necessary. The performance of this method remains low.

It is necessary to pay special attention to safety precautions. The welder must be carefully protected from the ingress of drops of metal and slag. It is worth considering where the molten metal will flow to avoid fire.

Applied methods

The electric arc is actively used not only for welding, but also for cutting metal. There are several types of arc cutting of metal parts: manual arc cutting with consumable and non-consumable electrodes, as well as air and oxygen arc cutting.

Manual electric arc cutting of metal: features, methods and technological process of work

Electric arc cutting is unique in that this method melts the metal in the place where the cut needs to be made. During operation, the molten metal is removed by the force of the arc pressure or flows down from its own weight.

Scope of application

Electric arc cutting is used only if the necessary equipment for gas cutting is not available.

In this way, they get rid of small excesses of metal blanks and correct defects by their surface smelting. Arc cutting with an electrode lends itself to non-ferrous products, high-alloy steels, as well as cast iron and various alloys.

Air and oxygen arc cutting

This method of separating metal parts differs from the previous ones in that the metal melted by an electric arc is immediately blown out by a jet of compressed air or pure oxygen. Usually this method is used in order to get rid of defects in the welding place and to separate stainless steel workpieces with a thickness of no more than 20 mm.

Due to the supply of oxygen, the metal is partially burned out, accompanied by the release of additional heat, which makes it possible to significantly speed up the melting process. This method is used if it is necessary to make a short cut on any building structure.

The separation is carried out with a graphite or steel electrode at constant current using special cutters. The electrode should be no thinner than 4-5 mm, coated with OMM-5, TsM-7 or OSZ-3. The current strength can reach up to 250A and allows cutting metal up to 50 mm thick. Compressed air is supplied from the side with a pressure force of 0.4-0.5 MPa. Average oxygen consumption varies from 100 to 160 l / min.

Scheme of air-arc cutting of metal

If you use a RGD type cutter, then the electrode holder is held in the right hand, and the cutter itself is held in the left. As soon as the metal begins to melt, a stream of air is supplied to it and blows it out.