Forge blowing forge. DIY forges: principle of operation, tips

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Do-it-yourself closed gas forge - the most common technical solution for a small forge in household. Availability main gas pipeline- not uncommon in modern houses, and the ease of adjusting the parameters of the propane mixture in combination with the high calorific value of the gas determines the appropriate efficiency of heating the metal for forging.

Key element gas forge is right choice(and sometimes production) of a fuel-burning device - a burner.

Types of burners used for gas combustion

The choice of the optimal design of the forge burner is related to the issues of the amount of metal waste during heating for forging, the intensity of surface scaling, as well as the total gas consumption. Closed-type furnaces require short-flame burners that provide rapid and intense mixing of the combustible mixture. It is then that the efficiency will be maximum, and the removal of combustion products from the working chamber of the forge will be uniform and efficient.

Thus, the gas burner must provide:

The greatest angle of inclination of the finished gas-air mixture at the entrance to working space forge.
High jet exit speed with a low height and large width.
Gas ignition safety.
Stability of the combustion process.
Insensitivity to high humidity inside the forge.
Security under the so-called “ back kick", when a sudden change in the direction of thrust can extinguish the torch, which almost immediately leads to an explosion of the flammable mixture in the furnace.

Gas burner drawings

Thus, for burning propane (from a cylinder or gas pipeline) the following are used:

Injector burners providing self-suction of gas. Despite their simplicity, they are characterized by low efficiency, since they allow adjustment of the ratio of components for a relatively small range of values. Regarding a home-made forge, this most often leads to the need to work with a lack of air;
Tangential type burners (point jet), when the gas flows along the axis, and air flow– tangentially to the mixer body. Mixing here occurs quite intensively, but pressure losses due to turbulence are also large. This affects the unevenness of the amount of air supplied to the forge, and it is greatest where the heated metal comes into contact with the hearth bottom. Accordingly, waste and scale formation increase. Positive quality tangential burners - their simplicity and reliability;
Vortex burners, where spiral guide plates are used to mix the flows. In such options, complete mixing occurs only at the mouth, so regulation by work in in this case– the best, and there is practically no pressure loss. Some of the disadvantages are the design complexity, which is why, even with drawings, making a vortex burner for a forge in a home workshop is very labor-intensive;
Combined burners that combine tangential and direct-flow supply. The adjustability of the combustible mixture is the best, since by changing the amount of air supplied between the internal and external channels, you can adjust the length of the torch in the forge and, therefore, control the heating time of the workpieces for forging. The disadvantage of such designs is their large dimensions, which may be unacceptable for small forges. Also, the technical complexity of manufacturing a dual-flow burner can be considered a minus.

Manufacturing and installation of a burner in a closed gas furnace

Let's consider two options - make a burner “from scratch”, using the recommendations of experienced home craftsmen, or use finished design, adapting/modifying some of its characteristics. It should be noted that in the first case you should have very high qualifications, as well as have experience in setting up and, at a minimum, repairing such devices. Otherwise, the matter may end in an explosion, burns, and other troubles.

The easiest way for a forge is to make a ball burner, which belongs to the group of fuel-burning units with a tangential supply of a torch to the working space of the forge. This burner consists of the following parts:

Confusion bell made of heat-resistant steel type X18N9T.
Steel tubular body shaped like a double truncated cone.
Gas supply head.
Air supply head.
Mouths.
Regulators for the amount of gas-air mixture.

To make such a burner you need: 1.5-inch pipes, a sheet blank with a thickness of at least 1.2 mm for the confuser, two fittings and three flanges for connecting the elements. Welded structure It is better to make it from heat-resistant steel, and welding must be done under submerged arc or using inert gas. Sleeves can be used as air and gas supply pipes high pressure, the diameters of which will correspond connecting dimensions housings. Fixing clamps and high-quality seals made of gasoline-oil-resistant high-temperature rubber are also required. All other elements are connected using threads.

On some sites there are recommendations for making a burner body using the rolling method tubular billet. But at high jet pressures, plastic hardening of the material can lead to the emergence of zones of internal stress, which, when starting the burner, often cause cracking in the body metal.

Option to install a used burner gas stove much easier. You will first need to determine the fuel costs required to quickly heat the metal for forging. When selecting a finished design, the power of the main unit (boiler, stove, etc.) for which the device was used is established. The product of this value by the efficiency (for gas it is 0.89...0.93) gives the desired power value W.
It is a little more difficult to establish the gas flow rate T. The calculation algorithm is as follows:

The calorific value of the fuel Q is determined (for propane, 3600 kJ/m3 can be taken);
Using the formula T = 3.6W/Q, the flow rate is determined.
Based on the calculation results, all the necessary shut-off and control valves are selected: valves, tees, etc.

Do-it-yourself installation of the burner in the forge forge in the following way. First, a confuser is inserted into the prepared lining hole, and the burner mouth is attached to it through a sheet gasket made of heat-resistant steel. The product itself is attached to it, and tubes for supplying air and gas are screwed in. They check the effectiveness of the regulators, after which they carry out a test run of gas from a cylinder or a stationary network. All work must be carried out in a well-ventilated area. At the slightest smell of gas, installation work is stopped and the source of possible leaks is determined.

It is quite possible to assemble a forge with your own hands, using most of the available building materials. Blacksmithing has now ceased to be a vital craft and has faded into the background as a hobby. If there suburban area and some free time, you can try yourself as a blacksmith, but for this you will need one of the main tools of any forging master - a forge.

The construction of a forge is simple. The forge is a furnace-type structure with three walls and one open side. Its main task is to maintain the maximum possible temperature inside. This simple design is used for heating and melting metal parts, as well as for heat treatment various materials. In the past, blacksmithing had wide application, now it has been replaced by machines. Machines and automatic installations carry out the same processing faster and more accurately. But for those who like to put their soul into their creations, it’s worth trying to equip your own forge. To begin with you will need homemade horn for forging.

By using various materials at home, you can achieve a forge power that will allow you to maintain temperatures up to 2000 °C. This is quite enough not only to soften metal parts, but also engage in full-fledged forging.

You can make a forge with your own hands using heat-resistant steel, cast iron, and brick. For this you can also use detail drawing design, which will help you navigate correctly during assembly.

Types of structures

A forge is assembled with your own hands depending on the fuel that will be used for heating, as well as the place of work. He can be small sizes and used for melting small crafts. To process large parts, you will have to open the top of the structure. In addition, forges can be made not only stationary, but also portable. The forge allows you to melt metal, but this requires space. The second option is more convenient, since moving the workshop to different time outdoors or indoors, will help maintain the work pace and comfortable conditions work. In addition, you can independently choose the size of the working area.

A homemade forge can operate on almost any type of modern fuel, but the most preferred are considered charcoal and coke. Using this solid fuel allows you to improve the final quality of metal products. One of modern options The design is considered to be a gas horn. It allows you to quickly reach the required temperature, but at the same time the quality of the products is partially reduced.

Principle of operation

Horns different types can maintain temperatures depending on the design, so drawings are the first thing to do. After choosing a drawing, you need to study the principle of its assembly and the features of the product.

A do-it-yourself forge is used as a chamber for melting and heating metals. High temperature allows for various operations with workpieces. How does this happen?

The flame creates required amount heat that is retained by the walls of the forge. Coal acts as a heat source. When the temperature in the cooking chamber reaches maximum norm, the workpiece is placed there. The part heats up and becomes more pliable for processing. From time to time after processing it is heated in a forge. Charcoal fire prevents oxidation and premature hardening of the part before finishing. Carbon dioxide, which is a product of burning coke and charcoal, absorbs oxygen particles. They are definitely present in the forge, as they are necessary to maintain the temperature.

The correct balance of retention in the forge flame allows you to harden the workpiece and make it more durable.

Build process

The simplest option is a mini forge. It is made from several bricks, a burner and a couple of steel blanks in the following sequence:

Fireclay bricks are used as walls; it is cheap, but retains heat. You will need 6-8 bricks, a gasoline burner.
2-3 bricks are used as the bottom, 2 to 4 go to the side walls, and the rest for the vault.
The walls can be supported with other bricks to reduce heat loss.
Coal spills out on the bottom.
The coal is set on fire.

Scheme of a mobile forge

A little bit more difficult option It is a large brick portable structure. Gas horn portable type quite simple to build from the above fireclay bricks. To do this, you should use a steel table or stand made of heat-resistant material.

The table is covered with bricks on top. In the center you need to leave a space for lighting a fire and connecting the burner to about 2-3 bricks. One row of material will be enough. The walls where the main fire will be should be slightly enlarged and made 2 rows, that is, add 1 brick on top.

The fire is supplied from below, igniting the coals and increasing the temperature in the forge open type. This table weighs a lot, but you can move it.

More powerful option

How to make a forge at home for large metal products? You will need several sheets of good steel from which you can make a closed frame.

It is best to make a box with a hole for the flame at the bottom. Refractory steel or cast iron will be required. It must be completely closed and insulated on three sides. The coal is placed above the hole where the flame supply will be located. Such a forge for forging on coal is capable of melting copper and even brass quite well.

A homemade coal forge allows you to melt metal and heat various metal products at home. It's quite easy to assemble, all you need is thermal insulation materials, as well as fire brick and burner. Everyone can choose the most suitable option for themselves, since drawings of various products are available in specialized literature.

A forge is an indispensable attribute of workshops engaged in the production of various products using the method of hand-made artistic forging. Only a certain number of forged elements can be produced by plastic deformation of metals at room temperatures. In most cases, heating is required. For steel, in particular, the range of optimal forging temperatures is (depending on the steel grade) from 800...900 0 C to 1100...1200 0 C. A forge is the simplest type of heating device, which is quite suitable for these purposes.

Invented by the ancient Khalibs for forging copper knives and scrapers (Middle East, 6th millennium BC), the first forge was made in the form of a primitive depression in the ground measuring about 700 mm. The pit was surrounded stone wall, in which a hole was provided for air injection. Air injection (which is necessary for stable combustion of fuel) was carried out using blacksmith bellows. They consisted of a cavity made of goat skins, into which air was blown through levers through an air valve. The reverse movement of the lever was ensured by a stone, which was installed on the top plate of the bellows, and the operation of the valve was carried out due to the difference in pressure of cold and hot air.

Existing forge designs are determined by the following factors:

Fuel, on which the device operates: coke, fuel oil, coal or gas.
Design fuel burning device.
Required sizes workspace.
Purpose, since, in addition to heating for forging, forges are also used for some heat treatment operations of finished forgings - carburizing, tempering and even hardening.

For safety reasons, forges are often fired with coal.

Coke is expensive, fuel oil has unsatisfactory environmental operating conditions, and gas furnaces require especially careful routine maintenance. At the same time gas furnaces are characterized by higher efficiency, and also allow for fairly convenient mechanization of some heating control processes - in particular, ignition of gas in the burner or burners.

Common disadvantages blacksmith forges are considered:

Uneven heating metal placed on the surface;
Impossibility practical temperature control heated workpiece;
Unwanted saturation surface layers heated metal sulfur compounds, resulting in increased fragility of the workpiece.

However, an experienced blacksmith is able to estimate the temperature of the metal by the color of its surface, and the problem of sulfurization is solved by using a higher quality type of fuel.

Fuel consumption during the operation of forges is 40...150% of the mass of the heated metal, with its surface loss of 4...7% (depending on the duration of heating). Modern forges are predominantly of the closed type, since otherwise the efficiency of the heating device drops to 5...10%.

Coal-fired forges

The design of a heating device of this type includes:

Arch and side walls, which are laid out from refractory bricks (fireclay or dinas).
Horn nest, formed by the upper surface of the arch, where the workpieces are heated.
Umbrella, equipped with folding curtains, and designed to improve natural traction in the workspace.
Rear wall (firewall), which provides openings for supplying source air.
Air valve, designed to turn on the air supply to the forge socket.
Protective box made of heat-resistant steel, which connects the inlet cavity at the air supply valve with the forge socket.
Quenching tank(it can be steel or brick), designed to cool the workpieces during heat treatment or to cool the hearth nest itself from overheating and subsequent formation of temperature cracks.
Chimney, through which fuel combustion products are removed.
Coal storage tanks and various blacksmith tools.

Schematic diagram of the operation of a forge

A solid fuel forge is a rather capricious heating device, and heating it requires a certain amount of practical experience from the blacksmith. It is especially difficult to ignite a forge that has not been used for a long time, and also if the external temperatures and air pressure are quite low. Coal, which is used in such forges, must comply requirements of GOST 8180.

Preparing the forge for heating metal is carried out in the following sequence:

Their furnace nest removes waste, leftovers forged metal, ash and scale (this should be done even when the surface has been thoroughly cleaned after completion of work);
Chimneys and air supply channels are purged compressed air (for small forges you can use a vacuum cleaner);
A small layer of coal is poured onto the surface of the forge nest., and the opening of the protective box should not be completely blocked;
Top on coal place the rags, soaked in flammable liquid or sawdust;
After ignition when combustion becomes stable, add the next portion of coal(the fraction may have an increased size compared to the original);
The air supply valve opens, and is installed in the middle position;
As it burns out, the blast intensity is gradually increased.

The required quality of heating the workpiece for forging in an open forge is ensured formation of a superficial crust, which is formed during fuel combustion.

Inside the crust - always more heat, so the workpiece is placed inside and covered with another dose of coal on top. At the same time, they try not to destroy the upper surface of the crust, since otherwise heating will be slower, and metal waste and scaling will increase. Sometimes, to weaken the processes of carburization of the metal, the crust is sprayed with water.

In open forges, the least intense heating of the metal occurs at the periphery of the forge nest, therefore fresh coal is poured precisely along the perimeter of the heated workpiece. If the crust layer becomes too thick (more than 5...10 mm), it is broken, because in this case, the thermal conductivity to the workpiece decreases.

The workpiece is periodically heated during heating. turn to provide all its parts with the same heating conditions. The flame when burning coal should have a uniform color with a minimum of soot.

Colors of heated steel at different temperatures are:

Dark cherry colors – 700...750 0 C;
Cherry red – 750...800 0 C;
Red – 800…850 0 C;
Light red – 850…900 0 C;
Orange – 900…1050 0 C;
Dark yellow – 1050…1150 0 C;
Light yellow – 1150…1250 0 C.

Overheating of the metal above the specified temperatures is unacceptable. Overheated metal is characterized by a coarse-grained structure, which is less susceptible to forging, especially when forming complex forged elements.

Gas-powered forges

Gas furnaces are brought to the design mode much easier, and this is their advantage over solid fuel heating devices. Typical design such a forge is next:

Camera, made of fire-resistant material and lined on the outside with thick sheet heat-resistant steel.
Front flap, opening with hinges or a counterweight, and equipped with a viewing window.
Under, made of heat-resistant fireclay bricks.
Burner. Burner type is determined calorific value gas used. For example, for a propane-butane mixture, diffusion combustion burners are effective, in which mixing of air and gas occurs only after the gas and air leave the device, and mixing of the components occurs due to diffusion processes. Such burners provide the most uniform heating of workpieces (especially long ones), and minimal metal waste is achieved due to the fact that there is always a protective layer above its surface.
Mixing reducer, providing mixing of air and gas (included in the structure of the liquefied gas cylinder).
Nozzle, the configuration of which is determined by the shape of the billets heated in the forge.
Grate, designed to improve traction and collect scale.
Fan, ensuring the injection of air in the required volume with its subsequent supply to the burner operating area.

To operate such forges, a stationary source of electricity is required. It is advisable to use gas forges for heating parts of long workpieces for forging: heating occurs much faster, and therefore, scaling is less.

When using a gas forge, the following safety requirements must be strictly observed:

Thoroughly ventilate the forge room. Avoiding stagnant zones where flammable gas can accumulate;
Do not use oxygen or oxygen-containing mixtures that are prone to spontaneous combustion and self-ignition near the operating device;
Provide for complete afterburning of gas in the working space of the hearth (determined by a gas analyzer, which is required during a test run of the gas hearth);
Thoroughly clean the grate after turning off the gas supply to the device.

In order to reduce scale formation, they are also used to heat workpieces for forging. and electric resistance heaters, but such devices can be called “forges” with great reserve.

Comments:

Nowadays, many men are inflamed with a passion for blacksmithing. The beauty of hot metal, transforming before our eyes into a beautiful forged product, is mesmerizing. Many of those who want to join this craft are frightened by the technical side of the issue: where to get or make a forge, what tools are needed, how to equip a forge so that there is no fire, etc. Here we will only consider the question of how to make a forge at home. All other issues can also be easily resolved if there is a strong desire.

Blacksmithing requires the presence of a forge and it is not so difficult to create even at home.

Varieties of forge

A forge is a special device for heating metal.

He can be the most different designs and use different kinds fuel. Single blacksmiths prefer to use a coke-fuelled forge. This type of fuel has a rather high price, but its ease of use, as well as its high combustion temperature and small amount of waste, compensates for any costs. One of the varieties of fine coke is called “coke”; most craftsmen prefer to use it, since there is no need to chop the coal themselves. You can use other types of coal as fuel, as well as charcoal, but why take the worst if you want to do everything well? Petroleum products or natural gas usually used in large enterprises.

The second sign by which a forge can be divided into varieties is its design feature, as openness, that is, there are open and closed views forge.

Scheme of the design of a mobile open-type forge.

A closed forge is a little more difficult to make than an open one. Its peculiarity is that the device has a special chamber in which the metal is heated. This type of forge is much more economical, but it imposes a limitation on the size of the workpiece outside its chamber.

The most common simple type of forge is the open one. It is extremely simply designed, as it consists of a certain container. A grate is installed on top, on which the coals will burn, and air is supplied from below. Such a forge has no restrictions on the size of the workpiece; it is placed directly on hot coals for heating.

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Making a forge with your own hands

In general, this completes the creation of a forge. Now all that remains is to pour coals onto the grate, set them on fire, turn on the air supply and place the workpiece on the hot coals. For better heating, you can add a little more coal on top. The second layer creates a kind of dome, under which even more intense heating occurs, sufficient to melt any workpiece.

In blacksmithing, a forge is used to heat and preheat metal blanks before heat treatment. The operating temperature in this device rises to 1200 degrees. By design, the device can be stationary and mobile (that is, placed directly in a specially equipped forge or transported to a place convenient for work). Equipment for industry is completed various devices, For household use The forge is produced in its simplest form.

Features of a household forge

Due to the high cost of smelting plants, not every user can buy such equipment special purpose. For household needs, it is not difficult to assemble a gas forge with your own hands. subject to the correct determination of the shape, power and design of the supercharging system. A simple household forge for artistic forging or casting of non-ferrous metal can be assembled from several fireclay bricks and sheet steel.

Making a forge at home for working with ferrous metal is not difficult. Make the simplest design possible from metal container, in the side of which it is necessary to make a hole for a gas burner. The fuel supply system can be assembled from a piece of pipe and coupling; long bolts are suitable for the supporting structure under the container. The lining of a gas fireplace is carried out by filling a solution of alabaster or gypsum, sand and water.

The forge must be equipped protective casing, ceramic tube or suitable sized bottle. After lining and drilling a hole for the gas supply, the device is installed in a convenient place, but at a distance from flammable materials. The advantages of the design include the ability to move the furnace and regulate the degree of heating of the workpiece, which is especially convenient when working with different forging materials.

Operating principle of the installation

Before you begin assembling the thermal unit, you need to understand the principles of operation of a homemade forge for forging metal to simplify the design of the furnace for home use. The operation of the device is based on the energy output when burning a mixture of carbon and oxygen, the percentage of metal released in molten form. During the smelting process, carbon stops the oxidation reaction of the metal; constant injection of gas into the fuel quickly increases the temperature in the forge.

The process of heating metal requires certain skills and specific knowledge. It is not enough to assemble a mini-forge with your own hands; you need to learn how to control the supply of oxygen to the fuel, the volume of which should be no more than 95%. If the workpiece overheats, carburization of the metal occurs, the steel becomes brittle, turning into cast iron.

When developing a drawing of a future blacksmith's device, special attention should be paid to the type of energetic substance that affects the design of the hearth. The type of fuel for the forge is:

gas (butane, propane);
liquid (diesel oil, fuel oil);
solid (charcoal, coke);
mixed (gas-liquid).

Depending on the planned work and the size of the workpiece, the thermal furnace can have an open or closed hearth zone. For the home handyman it should be remembered that domestic gas can be used in a furnace only after preliminary purification from sulfur using the method of “driving” through liquid naphthalene. Products made from heated gas burner metal cannot be used as loaded parts.

The main requirement for ensuring the security of the master is the installation of a powerful forced ventilation system, even if a household soldering apparatus running on bottled gas is used to construct the forge. The device will allow you to manufacture decorative elements interior and exterior in your own garage.

Making a stove from a blowtorch

Making a forge for forging with your own hands, blowtorch you need to install it in a recess, along the perimeter of which fireclay bricks with a grate are laid. When laying refractory bricks, it is necessary to maintain the distance between the enclosing elements in order to ensure the flow of air masses into the combustion chamber. The angle of the blocks relative to each other building material determined by the master.

Charcoal or coke is poured into a recess made of bricks on a grate, and a pipe is put on the blowtorch, which is fed under the grate. The blank for forging is placed in the gap between brickwork, the coal concentrate is ignited from below. To remove smoke, a probe, tent or chimney is installed above the grate.

Solid fuel device for forge

The simplest model of a solid fuel device for a private forge is an outdoor open stove, which does not require the installation of a ventilation system. The construction of the structure involves pouring reinforced concrete base, at the base of the structure it is necessary to lay wall bricks. The table is installed at a convenient height, a hole is left in one wall for the blower.

The mountain pit is laid out of fireclay bricks supported on steel corners; a cavity for the grate is left in the middle part of the structure. A chimney or probe will help ensure sufficient draft in the fireplace; the air supply system is installed at the final stage construction work. Installing an electric fan in the chimney or installing blacksmith bellows will help increase the draft.

In a home forge, the tank for hardening parts and the gas-air chamber are not mandatory elements. They can be useful in cases where thermal or shock hardening is required when working with damask steel. In the gas-air chamber the following is carried out:

drying and heating oxygen;
filtering oxygen from condensate and foreign impurities;
mixing air with additives for alloying steel.

To melt precious metals and create an alloy of non-ferrous metals, it is necessary to make a crucible from a heat-resistant material. The device, made in the form of a cap, allows you to increase the operating temperature in the furnace without the risk of overheating the workpiece and the formation of soot.

Home gas forge

To make a simple home gas forge, you can use parts from an old bicycle. If on lathe grind the sprocket from the gearbox; the device can operate on butane or propane and heat closed furnaces of small volume. An important condition use portable design It is prohibited to operate a burner with acetylene, since the high temperature of the flame can burn the former “star” and the furnace will simply explode.

Assembling such a device is not difficult, and a homemade forge for forge is not much inferior to industrial ones, but is much cheaper. The main thing is to follow safety rules during manufacture and use.

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