Homemade furnace for melting and hardening metal at home. Do-it-yourself aluminum melting furnace: types, manufacturing features and reviews Melting furnace for metal

A muffle furnace for melting or hardening metal products is a device that allows a home craftsman to perform a certain job. A simple unit capable of operating on different types of fuel for self-manufacturing It is enough to have the skills to perform metalwork and electric welding.

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Device and circuit

The device of a muffle furnace for melting metal consists of:

• in most cases steel case. For home use it is better to make it from heat-resistant metal or stainless steel. But you can use structural steel. Sheet thickness 1.5-2 mm;
• layer of internal insulation. For home stoves use fireclay bricks or other thermal insulation material, which can withstand heating temperatures up to 1000 0 - 1200 0 ;
• steel body can be overlaid with an outer layer ceramic tiles or refractory bricks;
• electric or gas heating elements. Gas-burners it is better to buy in specialized stores. An electric oven can be equipped with homemade nichrome or fechral spirals. Wire thickness - 1 mm. Fechral wire is cheaper, but it is inferior to nichrome in terms of resistance to aggressive environments and the durability of the spiral;
• system of automatic or manual control of the operation of equipment. By installing thermal sensors, you can easily control temperature regime and time to maintain the set temperature.

Output

Home-made or industrial furnaces for hardening metal or melting it - all these designs should ensure safety and comfort in working with heating devices. It is not difficult to make a design on your own, even a beginner can handle it. The main thing is to carefully and responsibly follow all the recommendations and rules for the performance of work.

Now furnaces with an induction system are widely used in the process of melting metals. The current produced in the field of the inductor contributes to the heating of the substance, and this feature of such devices is not only the main, but also the most important. Processing leads to the fact that the substance undergoes several transformations. The first stage of transformation is the electromagnetic stage, after it the electrical stage, and then the thermal stage. The temperature emitted by the stove is applied almost without a trace, so this solution is the best among all others. Many may be interested in the stove made. Next, we will talk about the possibilities of implementing such a solution.

Types of furnaces for melting metals

This type of equipment can be divided into main categories. At the first, the heart channel acts as a base, and the metal is placed in such furnaces in an annular way around the inductor. The second category has no such element. This type is called a crucible, and the metal is placed inside the inductor itself. In this case, it is technically impossible to use a closed core.

Basic principles

The melting furnace in this case works on the basis of the phenomenon of magnetic induction. And there are several components. The inductor is the most important component of this device. It is a coil, the conductors in which are not ordinary wires, but copper tubes. This requirement is set by the design of melting furnaces. The current that passes in the inductor generates a magnetic field that affects the crucible, inside of which the metal is located. In this case, the role of the secondary transformer winding is assigned to the material, that is, a current passes through it, heating it. This is how melting is carried out, even if an induction furnace is made by hand. How to build this type of furnace and increase its efficiency? This important question, which has an answer. The use of increased frequency currents can significantly increase the degree of equipment efficiency. For this, it is appropriate to use special power supplies.

Features of induction furnaces

This type of equipment has certain characteristic features, which are both advantages and disadvantages.

Since the distribution of the metal must be uniform, the resulting material is characterized by a good homogeneous mass. This type of furnace works by transporting energy through zones, and the function of focusing energy is also provided. Parameters such as capacity, operating frequency and lining method are available for use, as well as regulation of the temperature at which the metal melts, which greatly facilitates the workflow. The existing technological potential of the furnace creates a high melting rate, the devices are environmentally friendly, completely safe for humans and ready to work at any time.

The most noticeable drawback of such equipment is the difficulty of cleaning it. Since the heating of the slag occurs solely due to the heat released by the metal, this temperature is not enough to ensure its full use. The high temperature difference between the metal and the slag makes it impossible to make the process of waste disposal as simple as possible. As another drawback, it is customary to highlight the gap, due to which it is always necessary to reduce the thickness of the lining. Due to such actions, after a while it may turn out to be faulty.

The use of induction furnaces on an industrial scale

In industry, crucible and channel induction furnaces are most common. In the first, any metals are smelted in arbitrary quantities. Tanks for metal in such variants are able to fit up to several tons of metal. Of course, do-it-yourself induction melting furnaces in this case cannot be done. Channel furnaces are designed for smelting non-ferrous metals different types as well as cast iron.

Fans of radio engineering and radio technologies are often interested in this topic. Now it becomes clear that creating induction furnaces with your own hands is quite realistic, and a lot of people managed to do it. However, to create such equipment, it is necessary to implement the action electrical circuit, which would contain the prescribed actions of the furnace itself. Such solutions require the involvement of those capable of producing wave oscillations. A simple do-it-yourself induction furnace according to the scheme can be built using four electronic lamps in combination with one neon one, signaling that the system is ready to go.

In this case, the AC capacitor handle is not placed inside the instrument. Thanks to this, a do-it-yourself induction furnace can be created. The device diagram describes in detail the location of each individual element. You can make sure that the device is powerful enough if you use a screwdriver, which should reach a red-hot state in just a few seconds.

Peculiarities

If you are creating an induction furnace with your own hands, the principle of operation and assembly of which is studied and carried out according to the appropriate scheme, you should know that one or more of the factors listed below can affect the melting rate in this case:

Pulse frequency;

Hysteresis losses;

Generator power;

The period of heat release to the outside;

Losses associated with the occurrence of eddy currents.

If you are going to do an induction oven with your own hands, then when using lamps, you need to remember that their power should be distributed so that four pieces are enough. When using a rectifier, you get a network of approximately 220 V.

Domestic use of stoves

In everyday life, such devices are used quite rarely, although such technologies can be found in heating systems. They can be seen in the form of microwave ovens and in the environment of new technologies, this development has found wide application. For example, the use of eddy induced currents in induction cookers allows you to cook a wide variety of dishes. Since they take very little time to warm up, the burner cannot be turned on if there is nothing on it. However, special cookware is required to use such special and useful stoves.

Assembly process

Do-it-yourself induction consists of an inductor, which is a solenoid made from a water-cooled copper tube and a crucible, which can be made of ceramic materials, and sometimes steel, graphite and others. In such a device, it is possible to smelt cast iron, steel, precious metals, aluminum, copper, magnesium. Do-it-yourself induction furnaces are made with a crucible capacity from a couple of kilograms to several tons. They can be vacuum, gas-filled, open and compressor. Furnaces are fed with currents of high, medium and low frequency.

So, if you are interested in a do-it-yourself induction furnace, the scheme involves the use of such basic components: a melting bath and an induction unit, which includes a hearth stone, an inductor and a magnetic core. The channel furnace differs from the crucible in that the electromagnetic energy is converted into heat in the heat release channel, in which there must always be an electrically conductive body. To make the initial start-up of a channel furnace, molten metal is poured into it or a template is inserted from a material that can be cracked down in the furnace. When the melt is completed, the metal is not completely drained, but a "swamp" is left, designed to fill the heat release channel for future start-ups. If you are going to do-it-yourself induction furnace, then to facilitate the replacement of the hearth stone for equipment, it is made detachable.

Furnace components

So, if you are interested in a do-it-yourself induction mini-oven, then it is important to know that its main element is a heating coil. When homemade version it is enough to use an inductor made of a bare copper tube, the diameter of which is 10 mm. For the inductor, an inner diameter of 80-150 mm is used, and the number of turns is 8-10. It is important that the turns do not touch, and the distance between them is 5-7 mm. Parts of the inductor must not come into contact with its screen, the minimum clearance must be 50 mm.

If you are going to do-it-yourself induction oven, then you should know that in industrial scale the inductors are cooled by water or antifreeze. When low power and the short operation of the created device can be dispensed with without cooling. But during operation, the inductor becomes very hot, and scale on copper can not only drastically reduce the efficiency of the device, but also lead to a complete loss of its performance. It is impossible to make an inductor with cooling on your own, so it will need to be replaced regularly. Forced air cooling should not be used, as the case of a fan placed close to the coil will “attract” EMF to itself, which will lead to overheating and a decrease in the efficiency of the furnace.

Generator

When a do-it-yourself induction furnace is assembled, the circuit involves the use of such an important element as an alternator. You should not try to make a stove if you do not know the basics of radio electronics at least at the level of an average radio amateur. The choice of the oscillator circuit must be such that it does not give a hard current spectrum.

Use of induction furnaces

This type of equipment is widely used in areas such as foundries, where the metal has already been cleaned and needs to be given a specific shape. You can also get some alloys. In jewelry production, they also became widespread. The simple principle of operation and the possibility of assembling an induction furnace with your own hands make it possible to increase the profitability of its use. For this area, devices with a crucible capacity of up to 5 kilograms can be used. For small productions, this option will be optimal.

If you have a need for annealing metals, creating ceramics, smelting non-ferrous metals, including precious metals, you can build yourself such a simple furnace. Most of these stoves cost a lot of money, according to the author, in his region prices are in the region of $ 600-12,000 per stove. In our case, the oven cost only $ 120, not counting the temperature controller. This small oven can produce temperatures in the region of 1100 o C.

Homemade is assembled simply, all parts are not expensive, and they can also be quickly replaced if the furnace malfunctions.

Some craftsmen manage to make wedding rings, various talismans, brass knuckles and much more in such furnaces.

Materials and tools for homemade:

Materials:
- bolts and nuts (8x10, 1/4 inch);
- seven refractory bricks(they should be soft as they will need to be grooved, dimensions 4 1/2" x 9" x 2 1/2");
- a corner for creating a frame;
- a square sheet of metal for the door (the author used aluminum);
- a heating element (you can buy ready-made spirals for the oven, or wind your own from nichrome)
- heat-resistant screws-contacts for fastening the spiral;
- a piece of good cable (should withstand at least 10A).

From tools:
- hand drill with a suitable nozzle for cutting grooves in brick;
- wrench;
- pliers;
- hacksaw;
- drill;
- nippers and more.

The process of making a homemade oven:

Step one. Making grooves
First you need to decide how wide the spiral is, depending on this, the depth and width of the future grooves in the bricks are determined. Next, they need to be drawn on the brick with a pencil. The author’s grooves are shaped like the letter “U”, there are only two grooves of this shape, that is, they are cut out on two bricks. On the brick that will be in the back of the furnace, you need to make two parallel grooves as in the photo. As a result, after assembling the furnace, the spiral will receive an approximately “P” shape.

Well, then you can lay the oven in the groove. To fix the spiral, the author uses metal brackets, under which holes will need to be made in the brick. Special attention you need to pay attention to connecting the spiral to the wire. Here, special screws with ceramic washers must be used, and the screws must be taken longer. Otherwise, the insulation of the wire will either constantly burn and stink, or it will burn constantly due to the high temperature.

Our people learned how to make such contacts from old car plugs when they used ancient open-coil electric hotplates.

Particular attention should be paid to the choice of material from which the spiral is made. The maximum temperature that the oven can produce will depend on this. The spiral must withstand high temperature loads. For such purposes, the author chose a wire of the NiCr type. Most of these wires are designed for temperatures of the order of 1340 ° C. If you require higher temperatures, then you can choose other types of wire that are suitable for this.

Step three. We make the frame of the stove
To create a frame, you need a corner, you can use steel or aluminum. Four pieces of aluminum form the legs, and two more go to the bottom and support the weight of all the bricks. You can use not two corners, but four to create a lower support. However, this is not necessary, as a result, the structure is still pulled together with bolts and nuts, these bolts hold the bricks down.

In the upper part of the furnace, it will also be necessary to lay two or one and a half bricks, as well as below. Well, how everything is going, you can see in detail in the photo.

As a refractory material, the car used a Kaowool plate. It must be cut to the size of the previously drawn square. Well, then the plate is laid on the sheet, and the remaining edges of the sheet are bent, thereby holding the plate.

Step five. We supply electricity
To connect the spiral, you need to use a good wire with a thick core that can withstand at least 10A. Among other things, the oven is connected through a regulator, it will allow you to maintain the temperature in a given state. You will also need a furnace thermometer, by which it will be possible to more accurately monitor the temperature in the furnace.

For many years, people have been smelting metal. Each material has its own melting point, which can be reached only with the use of special equipment. The first furnaces for melting metal were quite large and were installed exclusively in the workshops of large organizations. Today, a modern induction furnace can be installed in small workshops when setting up the production of jewelry. It is small, easy to handle and highly efficient.

Operating principle

The melting unit of the induction furnace is used to heat the most various metals and alloys. The classic design consists of the following elements:

1. Drain pump.
2. Water cooled inductor.
3. Frame in stainless steel or aluminium.
4. Contact area.
5. Hearth made of heat-resistant concrete.
6. Support with hydraulic cylinder and bearing assembly.

The principle of operation is based on the creation of eddy induced Foucault currents. As a rule, during the operation of household appliances, such currents cause failures, but in this case they are used to heat the charge to the required temperature. Almost all electronics start to heat up during operation. This negative factor application of electricity is used to its full capacity.

Device advantages

The induction melting furnace has been used relatively recently. Famous open-hearth furnaces, blast furnaces and other types of equipment are installed at production sites. Such a metal melting furnace has the following advantages:

It is the latter advantage that determines the spread of the induction furnace in jewelry, since even a small concentration of foreign impurities can adversely affect the result.

Depending on the design features, floor and desktop induction furnaces are distinguished. Regardless of which option was chosen, there are several basic rules for installation:

The device may become very hot during operation. That is why there should not be any flammable or explosive substances nearby. In addition, according to fire safety regulations, nearby should be installed fire shield.

Only two types of furnaces are widely used: crucible and channel. They have similar advantages and disadvantages, the differences are only in the method of work used:

The crucible variety of induction furnaces is more popular. This is due to their high performance and ease of operation. In addition, a similar design, if necessary, can be made independently.

Homemade versions are quite common.. To create them you need:

1. Generator.
2. Crucible.
3. Inductor.

An experienced electrician, if necessary, can make an inductor with his own hands. This structural element is represented by a winding of copper wire. The crucible can be purchased at the store, but a lamp circuit, a do-it-yourself battery of their transistors or a welding inverter is used as a generator.

Using a welding inverter

A do-it-yourself induction furnace for melting metal can be created using a welding inverter as a generator. This variant is the most widely used since the efforts made concern only the manufacture of the inductor:

1. Thin-walled copper tube is used as the main material. The recommended diameter is 8-10 cm.
2. The tube is bent according to the desired pattern, which depends on the features of the body used.
3. Between the turns there should be a distance of no more than 8 mm.
4. The inductor is placed in a textolite or graphite case.

After the creation of the inductor and its placement in the housing, it remains only to install the purchased crucible in its place.

Such a circuit is rather complicated in execution, it involves the use of resistors, several diodes, transistors of various capacities, a film capacitor, copper wire with two different diameters and rings from chokes. Assembly recommendations are as follows:

The created circuit is placed in a textolite or graphite case, which are dielectrics. Scheme, involving the use of transistors, is quite difficult to implement. Therefore, it is necessary to undertake the manufacture of such a furnace only if there are certain work skills.

Furnace with lamps

Recently, lamp stoves have been created less and less, as they require care when handling. The applied circuit is simpler in comparison with the case of using transistors. Assembly can be carried out in several stages:

The lamps used must be protected from mechanical impact.

Equipment cooling

When creating an induction furnace with your own hands, the most problems arise with cooling. This is due to the following points:

1. During operation, not only the molten metal is heated, but also some elements of the equipment. That is why effective cooling is required for long-term operation.
2. The method based on the use of air flow is characterized by low efficiency. In addition, it is not recommended to install fans near the oven. This is due to the fact that metal elements can affect the generated eddy currents.

As a rule, cooling is carried out with water supply. Creating a water cooling circuit at home is not only difficult, but also uneconomical. Industrial versions of the furnace have an already built-in circuit, to which it is enough to connect cold water.

Safety

When using an induction furnace, certain safety precautions must be observed. Key recommendations:

When installing the equipment, consideration should be given to how the charge will be loaded and the molten metal will be extracted. It is recommended to allocate a separate prepared room for the installation of an induction furnace.

For a long time, men began to think about how to create their own furnace for melting metal at home. It must be portable and meet all conditions. Furnaces for melting a large amount of metal are installed at the production facility. At home, you can assemble a furnace for melting up to five kilograms of aluminum. Consider how to make a smelter at home.

Equipment and materials you will need

In order to smelt metal, you need to buy the following components for manufacturing:

• refractory brick;
• nails;
• transformer;
• copper wire;
• graphite;
• mica;
• asbestos and cement tiles;
• gas-burner;
• crucible.

Dimensions will vary from the desire of the person who collects it. It is better to create a small furnace for melting metals if you want to use it only for your own needs. You will spend less time on its manufacture, and a small number of kilowatts will be spent on heating it. If you are doing it on diesel fuel or on coal, then do not forget about installing thermal insulation and air blowing.

Metals such as iron, nickel, tin, copper are melted in an electric furnace. The output voltage in the electric furnace should be greater, which means that the distance between the electrodes will increase. Brushes from an electric motor are suitable instead of electrodes.

Step-by-step instruction

How to make a melting furnace at home - read the following instructions:

• A high-frequency alternator is installed.
• Spiral winding. Made from copper wire.
• Crucible.

All these elements are placed in one case. The melting cup is placed in the inductor. The winding is connected to a power source. When the current is turned on, an electromagnetic field appears. The resulting eddy currents pass through the metal in the cup and heat it. Melting occurs.

The positive properties of the induction furnace are that during the remelting of metals a homogeneous melt is obtained, alloying components do not evaporate, and melting occurs rather quickly. In addition, the installation of such a furnace does not harm the ecosystem and is safe for those who use it.

Cooling can be done with a fan. Only the latter should be located as far as possible from the furnace, otherwise its winding will serve as an additional closure of vortex flows. This will reduce the quality of the melt.

Features of melting of some metals

In order to melt metal at home, this element must be placed in a small cup or crucible. The cup with the material is inserted into the furnace. Then his melting begins. To melt precious elements, they are placed in a glass ampoule. In order to make an alloy of several components, follow these instructions:

• First, a refractory element - copper or iron - is placed in a cup for melting.
• Then a more fusible component is placed - tin, aluminum.

Steel is a refractory material. Its melting point is one thousand four hundred degrees Celsius. Therefore, in order to melt steel at home, you must follow the following instructions:

• To melt steel at home, introduce additional regenerators. If the stove is powered by electricity, then electricity is used.
• During induction heating, slags are added. They increase the speed of melting.
• Constantly monitor instrument readings. If necessary, lower the melting temperature, switching to a more moderate mode.
• It is always correct to determine whether the steel is ready for work or for melting. Follow all of the above steps. Only then will the output metal be of high quality.

To melt iron at home, the furnace must be preheated. First, a large piece is placed, and then small ones. Iron must be turned over in time. A properly molten metal will have a spherical shape.

If you are going to make bronze, then you first need to place copper in the melting hole. Since this component is more refractory. When copper is melted, tin is added.

Under no circumstances should elements such as cadmium, lead or zinc be melted. When burnt out, they form a poisonous yellowish smoke.

And when melting aluminium, tin or iron, it is necessary to observe slowness. Rivet slowly and do this with a small hammer. Frequently heat the material until it turns red and cool for cold water. Only then will you get the perfect alloy at the end.

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