Hot cutting of metal
Modern industrial production requires high-capacity metal-working methods, allowing to produce the maximum number of blanks of the required quality in the shortest possible time. These requirements are met by hot types of metal cutting.
Gas-oxygen cutting.
The working principle is based on the fact that in pure oxygen at temperatures above 1000 °C the metal melts and burns out. The cutting point is preheated to the ignition temperature of the material. Typically acetylene is used as the heating gas. The heating time is influenced by the thickness of the metal, its grade and the condition of the surface of the workpiece.
After the place of the cut is heated up, a jet of burning oxygen is poured into the nozzle of the cutter. It cuts through the entire thickness of the workpiece, moving smoothly along the mowing line of the cut. During the oxygen combustion process, oxides formed on the surface of the semi-finished material are also removed.
to make the cut qualitatively, it is important to maintain the same distance between the cutter and the workpiece during processing. This is not an easy task when using a hand-held oxy-oxygen torch. When the process is automated, cutting is performed at high speed with high-pressure oxygen, resulting in a significantly higher productivity and quality of cut.
The uniqueness of the method lies in the possibility:
The disadvantages of gas-oxygen cutting include:
- impossible to use when cutting non-ferrous metals (copper, aluminum), chromium-nickel and high-carbon steels;
- large width of cut, oxide formation, overlap, poor quality;
- inability to process curved surfaces;
- changes in the physical properties of the material in the incision area as a result of high-temperature exposure.
Plasma cutting of metal.
Type of cutting with plasma is based on the principle of intense melting of metal along the cut line by means of thermal effect of compressed electric arc and its subsequent evaporation. The electric arc produces a fully or partially ionized gas, or plasma. The temperature inside the gas plasma flow reaches 15 000 20 000 ° C, which allows to increase process efficiency many times over as compared to gas-oxygen cutting, and to eliminate the drawbacks of the latter.
Of all the types of metal cutting listed above, plasma cutting is currently the best choice for today’s metalworking industries due to its advantages:
- plasma cutting is precise and does not leave behind any overlap;
- Allows cutting along curved lines;
- excludes changes in the physical properties of the metal (overheating) due to the narrowly-directed heating of the cutting area;
- it is possible to cut titanium, copper, cast iron, specialized steel grades without changing the tool;
- equipment has no cylinders with explosive gas, respectively, does not require filling and delivery of these containers;
- does not require a special regime of compliance with fire safety measures;
- there is no need for preparatory cleaning, because the high-temperature impact effectively removes impurities (rust, dirt, paint), and the quality of the cut remains unchanged;
- no special additives are needed for non-ferrous metals, cheap electricity and air are used, consumables are only nozzles and electrodes, so plasma metal cutting is a cost-effective technological process.
Disadvantages of this type of metal cutting:
- Due to exposure to high temperatures, the properties of the edges of the workpiece change. They become harder, some of the material is lost, so you need the extra cost of machining the edge. In any case, the quality of the edges after plasma cutting is much better than after gas-oxygen cutting: no dross, the width of the color-bleached zone is five times less.
Laser metal cutting.
This type refers to innovative technological processes. Its essence is intensive exposure of metal to a narrow laser beam with a stable frequency and wavelength. It can focus on a small area of the surface with optics controlled by a special computer program. This technological solution makes laser cutting unequalled in terms of precision.
The high energy density characteristic of directional and narrowly concentrated laser radiation makes it possible to heat and vaporize a strictly defined area of the metal workpiece.
Laser cutting occurs as follows:
When the laser beam plunges into the metal, the temperature rises, causing the material to melt and boil. The process consumes a lot of energy, so in order to save energy an auxiliary gas is fed into the cutting zone with which plasma cutting is performed. Depending on the material’s thermal properties, the auxiliary gases may be regular air, nitrogen, oxygen, inert gas.
Advantages of laser type of metal cutting:
- Narrowest cuts possible;
- No deformation when cutting thin sheets of steel and soft semi-finished products;
- Possibility of precise cutting along complex contours
- minimum number of irregularities;
- Small heat-affected zone;
- Versatility of the method. suitable for any alloy;
- easy control of the laser cutting machine.
The only disadvantage of laser cutting is the small thickness of the metal that can be cut.
Mechanical metal working
Highly sharpened blade made of the hardest steel is used. It is usually pre-treated by heat treatment. hardening. After that, its chemical structure changes, granularity, and the intermolecular bonds become stronger. Also requires a press or other indirect force application. Examples might be:
- band saw (it can be made at home);
- Guillotine. works on the principle of lowering the cutting part with acceleration;
- circular saw.
Let’s take a closer look at some of the tools below.
Hand scissors for cutting metal
Great for use at home, and often used in small batch production and by hand when a single operation is required, such as at a car repair shop.
The peculiarity of use. they can be used only for metalworking of sheet steel, with a thickness not exceeding three millimeters. They have their own varieties:
- for straight cutting. the most classic ones, have slightly rounded blades to increase the force applied to a single point, they look like a standard stationery device;
- for curvilinear. they are much more convenient to make artistic cuts, as well as to make holes;
- Finger blades. have rounded edges;
- having only one movable part, the other half is fixed to the table.
Also, all products are distinguished on the right-hand and left-hand sharpening. The convenience of turning during the process depends on it.
Their design feature is that the handles are longer than the cutting part, it helps to increase the pressure force. The material from which they are made is also important. the hardness of the steel should not be lower than 52-60 HRC. Blades should not adjoin closely, but with a gap, if it is not there, they will quickly fail, and if too large, the sheet will crumple.
Saws. a device, what to saw metal with
There are many of them, the choice depends on the purpose of use, the desired result. Below we will talk more about some of the most common types, but for now we will present a complete list:
- Hand-held slicing. This is a frame that has 3 sides of a quadrilateral. A toothed band is inserted in the quadruple. They blunt quickly and must be replaced, but are the cheapest. Has one handle.
- Disc-shaped. Electric drive, handy shape (can be held with one hand) and replaceable disks.
- Ribbon. The cutting blade moves in a big circle, while the workpiece lies on the frame. The operator has to move the steel plate. Suitable for sawing straight pieces.
- Trim or trimmer. It is easy to work with small plates. The workpiece must be placed and fixed in the mechanism, and a circular saw is lowered from above at a given radius.
- Pendulum. A variation of the previous model, but with a larger cross section.
- Circular. Very easy to use, has more power than the first two, but more maneuverable than the others, because it is controlled manually.
Angle grinder (angle grinder)
Convenient equipment, which is what to cut iron at home. Common name. angle grinder. It has stuck since Soviet times, because the first machines were brought from Bulgaria.
The peculiarity and advantage of the product is the possibility to make the cut not only of steel sheets, but also of any metal parts. metal profiles, pipes, metal tiles, etc. But it should be warned that this is one of the most traumatic procedures.
Changeable abrasive (diamond discs can not be used) can be of different diameters (from 125 to 250 mm) and thickness. The choice depends on the depth of cut required.
Pipe cutters. what to cut metal with
Structurally similar to a hand saw, but much more practical. Cutting part looks like a small disc, located inside the vice. the pipe itself is clamped in it. The movements are fast and the result is of high quality. Maximal diameter is 4 inches, minimal diameter is 4 inches ? The structure usually consists of three rollers, two of which are movable and the third is static.
Pliers
They are used everywhere to cut wire or bars with a small cross section. But there is also a counterpart for more durable, cylindrical, incomplete products. bolt cutters. It is designed for breaking fixtures and bolts, and is equipped with double springs, so the lever doubles the applied force.
Hacksaw
Metal cutting with a hacksaw was practiced in Soviet times, the tool is suitable for cutting thick profiles and re-sawing medium-diameter pipes and rods. The following types of devices are on sale:
- Professional tools. wear-resistant, allow you to achieve precise results, equipped with a rubber handle.
- Hacksaw handle. helps to perform a cut in the most inaccessible places, craftsmen with its help can perform internal cuts.
- Home-made hacksaws. low-cost, easy-to-use.
Such devices have an integrated screw mechanism and a handle made of wood.
Saws blades differ in hardness of cutting material and height of teeth, which must be taken into consideration when purchasing.
How to cut metal manually
Metal cutting is one of the most common ways of working this strong, hard and resilient material. Without the use of sophisticated equipment, with the help of simple mechanical devices you can get parts of the required shapes and sizes at home. Let us consider the basic tools and the range of tasks that are solved with their help.
Manual metal cutting is performed with or without chip removal. In the first case, hacksaws are used, in the second. scissors, pipe cutters, wire cutters. Depending on the thickness, shape, and size of the metal profile, preference is given to one or another tool.
Hand scissors are used for cutting sheet steel with a thickness of 0.5 to 1.2 mm. They allow for considerable effort thanks to their long handles and short blades, which are hardened to a high hardness (52. 60 HRC).
A distinction is made between left-hand and right-hand shears. Left-handed scissors are called scissors with bevel of lower blade on the left side. They are convenient for cutting metal in a straight line as well as counterclockwise.
Hand scissors can be with straight or curved blades. The latter are used when cutting out holes, complex-shaped parts.
Edges of scissors must be sharpened and fit together with a small gap along their entire length. If the gap is small, it will lead to fast tool wear, if it is big. to metal crushing.
Manual reinforced scissors have the same dimensions as the standard scissors. However, they allow for higher forces thanks to a system of two levers connected in series with each other.
Lever scissors are used for cutting steel up to 4 mm thick and base metal up to 6 mm thick. They consist of two blades, one of which is fixed to the base and the other is set in motion with a long handle. In addition to sheet steel, manual lever scissors allow you to work with bar and profile metal.
Hacksaws consist of a frame and a hacksaw blade. They are used for cutting profiles, sheets and blanks. Hacksaw frames are made solid or sliding, allowing the use of blades of different lengths.
Hacksaw blade is a 60÷63 HRC hardened narrow steel plate with teeth. The thicker the object to be cut, the coarser the teeth need to be. The number of teeth per unit length can vary. In locksmithing for soft metals, hacksaw blades with 16-18 teeth per inch are usually used.
Pipe cutters are used to cut metal pipes of varying diameters. ¼. 4 inch. They are more productive than hacksaws.
Small-diameter pipes are cut with three-roller pipe cutters. They have two rollers (discs) fixed in the body on fixed axles. The third roller is pressed against the pipe with a screw in the process of cutting.
Pliers are designed to cut metal bars, wires, wires. According to the location of the cutting edges there are two types of this tool: end and side cutters.
Bolt cutters are for cutting through thick wire, bolts, fittings. They allow you to develop significant cutting forces due to their dual lever design.
Thermal methods
Earlier we talked about the mechanical effect, but for all the positive aspects of the process, we can note the low productivity of such works. Now let’s discuss the options that allow instant heating of the desired area to the melting temperature, followed by evaporation of substances. Technologists are usually only used in large production facilities, because they are quite costly.
Gas cutting
The procedure is as follows. Abrasives are for cutting metal. The abrasive discs are coated with these. But modern methods help to apply air or other gas at such a pressure that the sand particles it contains make a smooth cut. The oxygen passes through the torch and is heated to a temperature that can withstand the plastic deformation threshold of the steel.
Gas-electric technology
An electric arc is ignited in the machine, as in welding, and is directed to a specific area. Nearby, there is a tube (nozzle) that supplies a jet of oxygen to the area. The air is accelerated to a very high velocity, and simply blows the molten metal substance away.
Plasma cutting
It is the most modern and economical process of those mentioned above with the highest degree of precision. The basic element is an ionized gas that undergoes a multi-step process and is transformed into plasma. The jet makes the cut very precisely and quickly. At the same time, it is so thin and smooth that the procedure is suitable for artistic patterns.
Disadvantages of plasma cutting
- a large amount of noise in the workshop;
- equipment is not simple. not everyone can handle it properly, training is required;
- the maximum thickness of the workpiece is 10 cm;
- high cost of the machine.
Now let’s talk briefly about the methods used in the home.
Professional methods
This category includes machining with plasmatrons, the use of electroplating lasers, multifunctional machines and other specialized equipment. The point is that you do not solve the problem yourself, but entrust the company, for which this is a core service, and it makes the required number of parts within a specified time and is responsible for the quality, accuracy, cleanliness of the seams. sells band saws, to clarify the information you are interested in, please contact our managers by contact phone numbers listed on the page. They will answer all your questions So, you know what tool is used for metal cutting at home, what is better for cutting. gas or plasma technology, and much more. We hope that now it will be easier for you to choose the method of treatment of workpieces.
Thermal methods
Earlier we talked about the mechanical effect, but with all the positive aspects of the process, we can note the low productivity of such works. Now let’s discuss the options that allow you to instantly heat the desired area to the melting temperature, followed by evaporation of substances. Normally only used in large plants, because they are quite expensive.
Gas cutting
The procedure is as follows. Abrasive is what you can cut metal with. That’s what the abrasive discs are coated with. But today’s processes use air or other gas at such a pressure that the sand particles in the air produce a clean cut. The oxygen passes through the torch and is heated to such temperatures that it overcomes the plastic deformation threshold of the steel.
Gas-electric technology
An electric arc is ignited in the machine, as in welding, which is directed to a specific area. Nearby there is a tube (nozzle) that brings the oxygen jet to this point. Air is accelerated to a very high speed and simply blows the molten metal material away.
plasma cutting
This is the most modern and economical method of all of the above with the highest degree of precision. The basic element is an ionized gas that undergoes a multi-step process and is transformed into plasma. The jet makes the cut very precisely and quickly. it is so thin and smooth that the procedure is suitable for artistic patterns.
Disadvantages of plasma cutting
- A lot of noise in the shop;
- Not simple equipment. not everyone will be able to handle it correctly, you need training;
- The maximum thickness of the workpiece is 10 cm;
- high cost of the machine.
Now let’s talk briefly about the methods used in the home.
What to cut metal with: how best to saw thick iron at home, methods and types of equipment
A blade with a high degree of sharpening made of the hardest steel is used. It is usually heat-treated beforehand. hardened. After that its chemical structure, granularity, and intermolecular bonds become stronger. Press or other indirect force is also required. Examples include:
- Band saw (it can be made at home);
- Guillotine. works on the principle of lowering the cutting part with acceleration;
- circular saw.
Let’s take a closer look at some of the tools below.
Hand scissors for cutting metal
Great for use at home, but also often used in small-scale production and when working by hand when you need to make a single operation, for example, in the car repair shop.
The peculiarity of use. they can be used only for metalworking of sheet steel, with a thickness not exceeding three millimeters. They have their own varieties:
- for straight cutting. the most classic, have slightly rounded blades to increase the force applied to a single point, look like a standard stationery tool;
- for curvilinear. they are much more convenient to make artistic cuts, as well as to make holes;
- finger-shaped. they have rounded edges;
- With only one moving part, the other half fixed to the table.
Also, all products are differentiated into right- and left-handed by sharpening. The convenience of turning during the process depends on this.
Their design feature is that the handles are longer than the cutting part, this contributes to increased pressure force. The material from which they are made is also important. the hardness of the steel should not be lower than 52-60 HRC. Blades should not adjoin closely, and with a gap, if it is not present, they will quickly fail, and if too large, the sheet will crumple.
Saws. a device than to saw metal
There are many of them, the choice depends on the purpose of use, the desired result. Below we will talk in more detail about some of the most common types, but for now we will present a complete list:
- Manual cut-off machine. It is a frame that has three sides of a quadrangle. A toothed band is inserted into the quadruple. They blunt quickly and need to be replaced, but they are the cheapest. Have a single handle.
- Circular. Has an electric drive, comfortable shape (can be held with one hand) and replaceable discs.
- Ribbon. The cutting blade moves in a large circle while the workpiece lies on the frame. The operator must move the steel plate. Suitable for sawing straight elements.
- End-face or trimmer. It is easy to work with small plates. In the mechanism you must put and fix the workpiece, on top of a given radius is lowered circular saw.
- Pendulum. A variation of the previous model, but with a greater reach.
- Circular. Very easy to use, has more power than the first two, but more maneuverable than the others, because it is controlled manually.
Angle grinder (angle grinder)
Convenient equipment, which is what to cut iron at home. Common name. angle grinder. It has stuck since Soviet times, because the first machines were brought from Bulgaria.
The peculiarity and advantage of the product is the ability to cut not only sheet steel, but also any metal parts. metal profiles, pipes, metal tiles, etc. But it should be warned that this is one of the most traumatic procedures.
Replaceable abrasive (diamond can not be used) discs can be of different diameters (from 125 to 250 mm) and thickness. The choice depends on the depth of cut required.
Pipe cutters. something to cut metal with
Structurally similar to a hand saw, but much more practical. The cutting part looks like a small disc inside a vice that grips the pipe. Moves are fast and the result is high quality. Maximum diameter is 4 inches, minimum diameter is 4 inches ? The design usually consists of three rollers, two of which are movable and the third is static.
Pliers
They are used throughout for cutting wire or small wire rods. But there is also a counterpart for more durable non-cylindrical products. bolt cutter. Designed for rebar and bolt breaking, it has double springs, so the lever doubles the force exerted.
This tool can cut most sheet metals in thicknesses of 0.7-1.0 mm, aluminum up to 2.5 mm. Scissors design consists of two cutting blades fixed at a certain angle and two handles. For ease of use (reduced cutting forces), the angle of attachment is from 7 to 12 degrees. Cutting blades are wedge-shaped with an angle of sharpening from 65 to 80 degrees. The smallest angle allows you to work with the softest metals, the largest angle is designed for cutting hard metals.
Metal scissors can be of the following types:
- Straight cut scissors can be used to cut metal in a straight line or to cut a circle of large diameter.
- To cut a small piece on the contour, to make a curved piece or to make a hole in the metal sheet the scissors with curvilinear blades are used.
- Finger scissors have narrow, thin blades and are usually used for the same purposes as curved scissors. scissors can be right or left-hand cutting. It depends on the position of the upper blade in relation to the lower blade.
- Chair (roofing) scissors are used when working with slightly thicker sheet metal (up to 2-3 mm).). A distinctive feature of such scissors is the design of the handles, the lower of which has a bend at the end. This end of the chair scissors can be attached to the workbench and by pushing the handle with the whole hand you can increase the cutting force.
- Power scissors (scissors H.А.Vasiliev). These scissors have one handle with two levers that are connected by a hinge. Specially designed shears allow for cutting metal sheets up to 2.5 mm thick. Another feature of the power scissors is the interchangeable blades and availability of disks for cutting metal bars with a diameter of up to 8 mm.
- Lever-action hand scissors are fixed on the workbench with the base, in the body of which there is one blade of the knife. The second (moving) knife is controlled by the handle. Lever scissors are used to cut soft sheet metal (e.g., brass) up to 6 mm thick and steel sheet up to 4 mm thick.