What temperature does metal melt at?

How to properly melt brass at home

To organize the melting of metal at home, it is necessary to make a device in which the workpiece could be heated to the required temperature. To melt tin and lead, it is enough to load the raw materials into a metal container and put it on fire. Then for casting copper alloys you will need to purchase a special furnace.

How to melt brass at home will be discussed in this article. But before we begin to describe the main stages of the work, it is necessary to study theoretical information about the metal alloy.

What is brass made of?

Brass, the alloy composition of which can vary significantly, necessarily contains copper in an amount of at least 55%. The remaining 45% of the two-component alloy consists of zinc. Zinc in the copper alloy significantly increases the mechanical strength of the alloy and corrosion resistance.

In addition to zinc, multicomponent brass may contain:

• Aluminum.
• Tin.
• Nickel.
• Manganese.
• Silicon.

Additional additives are necessary if it is necessary to provide the metal alloy with new properties that will facilitate easier formation of the product during casting and during machining.

To melt brass, the alloy must be heated to 880 - 950 degrees. Exactly what temperature is required for melting a particular type of brass depends on its composition, but when melting metals at home, it is not always possible to determine the grade of the alloy.

To guarantee melting of brass at home, you should purchase a special device in which the metal is heated to the maximum melting temperature.

Making a melting device yourself will require significant time and special knowledge. Therefore, it is much easier to purchase ready-made melting furnaces in specialized stores that run on gas or AC power.

Furnace and tools for melting brass

To cast brass at home, you need to purchase a special furnace.

At home, it is best to use small devices with a maximum heating temperature of 1300 degrees. Such a limitation is necessary to prevent burnout of the zinc contained in this copper alloy.

1. Graphite crucibles are used as a container for melting brass.
2. You will also need to purchase tongs and a large spoon. Tongs are needed to install and remove the crucible from the furnace, and a spoon is used to remove slag that forms on the surface of the melt.
3. A casting ladle is used to pour the molten brass from the crucible into the mold. Without this device, it is impossible to safely tilt the hot crucible during smelting operations.

Work with the melt must be carried out without any deviations from safety regulations, therefore, in addition to equipment for melting, you should definitely purchase protective clothing, eye and breathing protection.

When brass melts, harmful fumes are formed that negatively affect human health.

1. It is strictly prohibited to carry out smelting work without a respirator. Special glasses or a mask are used to protect the eyes from exposure to infrared radiation, which, with prolonged exposure, can cause damage to the organ of vision.
2. It is also necessary to use a heat-resistant apron to protect clothing from possible contact with molten metal and thick gloves to avoid burning your hands during melting work.

When all the necessary tools and fixtures have been purchased, you can begin preparing to melt the brass.

Preparatory work

In order for the melting of a copper alloy to be carried out according to all the rules, it is necessary to prepare tools and a place for work.

The best option for placing a furnace for melting brass is a canopy in the fresh air. Installing a stove outdoors allows you to minimize the harmful effects of zinc vapor, as well as ensure good fuel combustion when using a gas stove.

In terms of fire safety, placing a high-temperature furnace outdoors is the most appropriate. If it is not possible to install the melting furnace in this way, then the room in which the melting work is planned to be carried out must be equipped with a forced air ventilation system.

The surface on which the stove is installed, regardless of its location, must be made of non-combustible materials. It is also recommended to install a box with dry sand to safely move the crucible with molten metal. To prevent splashing of molten metal, it is recommended to carry out mold pouring work only over a container with sand.

1. If scrap metal will be used to obtain the melt, then before starting melting, the brass surface should be thoroughly cleaned of dirt and paint.
2. When using rolled non-ferrous metal, it is enough to cut it into pieces, the size of which will not exceed the parameters of the crucible of the melting furnace.

Such preparatory work will allow for better melting of metal with less slag, and the process itself will be more fireproof.

Brass melting process

After the preparatory stage, you can begin to directly melt the copper alloy.

The work is carried out in the following sequence:

1. In the oven, the molds are heated to a temperature of +100 degrees. It is also necessary to warm the spoon well before use. This procedure is necessary to completely evaporate moisture from the surface of the instruments. After warming up, the molds must be placed on dry sand.
2. Pre-prepared brass scrap or crushed rolled metal for melting is placed in the crucible in the required quantity.
3. The oven heats up to a temperature of +500 degrees.
4. The crucible with brass is installed in the furnace and the temperature rises to 950 degrees.
5. When the metal has completely melted from its surface, you must carefully remove the resulting slag and oxidation products using a spoon.
6. When the brass acquires a bright yellow color, you can begin filling out the prepared forms. For this purpose, the crucible is removed from the furnace with special tongs and installed on a casting ladle. Then the molds are filled with melt.

If it is necessary to continue melting the metal, the crucible must be filled again with the prepared material and installed in the melting furnace.

Tips and tricks

1. There are a large number of furnaces for melting metals on the market and it is not always possible to make the right choice of device. Especially if you have no experience in smelting. So that the furnace can be used not only for melting brass, it is recommended to choose a device with the ability to heat up to 1300 degrees. For example, the melting point of bronze is about 1150 degrees and low-power devices will not allow the melting of this non-ferrous alloy.
2. For each type of non-ferrous metal it is necessary to use a separate crucible, therefore it is not recommended to melt bronze or any other metal or alloy in a container in which brass was melted.
3. It is not recommended to wear synthetic clothing while performing smelting work. This fabric ignites and melts easily. In case of fire, may cause serious burns.
4. In the immediate vicinity of the place where the melting furnace will be installed, it is necessary to place a container with cold water. Such a protective measure will allow, in the event of a burn, to instantly reduce the temperature of the affected area of ​​the body.
5. The fire extinguisher must be located in direct access to the place where smelting work is carried out.
6. The moment of complete melting of brass can be determined by eye.

   It is necessary to pour products from this alloy when the surface of the molten metal begins to glow yellow with a slight orange tint.

7. During melting, brass is strictly prohibited from stirring. This action can lead to the formation of air bubbles, which will negatively affect the density of the material, its mechanical and aesthetic properties.
8. The exact melting point of brass depends on its brand.

   When determining the melting point experimentally, care must be taken not to overheat the mixture so as not to accelerate the oxidation process of the metal alloy.

9. You can make a furnace for melting brass yourself, but only with special knowledge. If difficulties arise in this matter, you can seek advice from experienced craftsmen.

Significant savings can also be achieved by replacing the graphite crucible with a ceramic product.

If you purchase special refractory clay, you can learn how to make containers for melting furnaces yourself.

Ceramic crucibles have a significantly shorter lifespan, but in cases where it is possible to independently manufacture such parts, the money savings will be significant.

Conclusion

At what temperature copper and its alloys melt is described in the article, but theoretical knowledge alone is not enough to become a professional in this matter.

Once a brass melting furnace has been purchased or installed, it is necessary to melt a small amount of metal to test the functionality of the equipment. And gain experience in melting copper alloys at home.

(4 3,75 out of 5)

Source: https://plavitmetall.ru/obrabotka/temperatura-plavleniya-latuni.html

Melting point of gold: what is it, ways to melt the yellow metal at home | mk-soyuz.rf

Hello my readers! As a child, I thought that if you boiled my mother's ring in a saucepan, it would melt. I really wanted to see how metal melted, and I managed to conduct a dozen experiments before my mother found out that she was growing up a metallurgist. Neither experiment was successful because the melting point of gold is 1064.4 °C (degrees Celsius), and water boils at only 100 °C.

Now I have grown up and I know that everything is not so simple. But melting gold at home is still possible, although it requires more than just a saucepan and gas.

Gold is a medium-melting metal: those that melt (transition from solid to liquid) at temperatures from 600 °C to 1600 °C are considered to be such. Many metals (nickel, iron, cobalt, silver) and alloys (steel, brass, cast iron) fit the definition of medium-melting metals. Gold can be smelted using tools suitable for most metals. The boiling point of gold is 2700 °C. In addition, it has:

• high ductility and malleability,
• very high density,
• low hardness.

A bar of pure gold can be forged into thin wire without the use of high-tech equipment. With simple tools and skills, this is theoretically possible even at home, because gold is very malleable and easy to process.

How gold raw materials are processed

Before turning into an ingot, coin or jewelry, the precious metal undergoes multi-stage processing. The charge - the material to be sent to the smelting furnace - can consist of both grains of gold mined in nature and scrap (watch, jewelry, technical, dental). Preliminary manipulations are aimed at making this mixture as homogeneous as possible before melting. To do this, processing plants subject raw materials to the following procedures:

1. Mechanical cleaning: crushing large pieces, grinding and sifting under running water or a solution with the addition of an abrasive, which additionally washes the mixture from dirt.
2. Chemical purification from impurities - refining. Variations: amalgamation, dissolution in aqua regia or leaching - cyanidation or using theourea solutions.
3. Precipitation of metal from the resulting solutions.

As a result of purification, gold is at the disposal of a factory worker (or a private jeweler) - in an amount much smaller than the original charge, but practically pure.

You can start melting.

At what temperature does it melt?

When I said 1064.4°C, I was talking about pure .999 gold. You and I can only find it in the form of bank bars (or if we engage in refining ourselves). In jewelry, industry and medicine, diluted alloyed metal is used.

The ligature is introduced into jewelry for strength, into solders - to increase fluidity and achieve the required parameters of the alloy for soldering products of each sample (color, fusibility). Here is a comparative table of temperatures at which samples with different percentage and quality content of alloy are melted:

Color	Try	Au (gold)	Ag (silver)	Pd (palladium)	Cu (copper)	t (°C)
yellow	375	~37.5 %	~10 %	~3.8 %	rest	926–949
yellow	585	~58.5 %	~8 %	No	rest	878–905
green	585	~58.5 %	~30 %	No	rest	835–880
red	585	~58.5 %	No	No	rest	907–922
yellow	750	~75 %	~17 %	No	rest	920–930
pink	750	~75 %	~12.5 %	No	rest	900–920
white	750	~75 %	~5 %	~20 %	No	1270–1280

The need to change the melting temperature of the alloy especially often arises in the manufacture of solders. More low-melting additives lower the melting point of gold:

• zinc,
• tin,
• magnesium,
• aluminum,
• silver (negligible).

More refractory metals and their alloys increase the melting point - in jewelry and industry this is mainly the platinum group:

• platinum,
• palladium,
• osmium.

Most intermetallic alloys are brittle, so they are almost never used to create jewelry, and their suitability for industrial use is limited.

Melting methods and process temperatures

Gold smelting factories have special smelting furnaces that can easily create temperatures of 1200 °C and higher. It is impossible to install one at home. Jewelers use portable melting furnaces, such as induction. Some hobbyists melt metals in microwave ovens, but it will no longer be possible to cook food in such a microwave - keep this in mind before choosing your method.

The “classic” method for private gold miners and jewelers who do not work with large volumes of raw materials is a gas or gasoline burner with an injector and a crucible - a fireproof container of suitable size.

Is it possible to melt gold at home?

Can! But we need to prepare.

Necessary equipment and materials

To make your own castings you will need:

• melting crucible - ceramic or graphite, resistant to high temperatures,
• burner and fuel for it,
• metal tongs,
• the form into which you will pour the molten gold (mold),
• borax (sodium tetraborate, you can buy it at the pharmacy) as a flux for cleaning the melt,
• wooden or graphite stirring stick,
• access to clean water,
• auxiliary containers, napkins, protective accessories (gloves, mask).

Batch preparation

Most likely, the available raw materials can fit in the palm of your hand, so we will not imitate the factory technological process, but will simply check the scrap for the presence of unnecessary debris. If you have refined metal in your hands, then it is probably already crushed and suitable for melting - just rinse it.

If our charge is jewelry scrap, we can melt it down, but the output will not be a pure ingot, but an alloy of unknown quality (as a rule, we do not know what and in what proportions is included in the jewelry). The scrap must be thoroughly crushed before melting.

Melting process

Don't forget to wear gloves, sunglasses and be mentally prepared for the meltdown. You need to melt gold in a clean, dried crucible, sprinkling borax on both the crucible and the charge. When the mixture of borax and gold becomes homogeneous, you need to sprinkle the melt with powder a second time.

Apply the flame of the burner to the gold carefully, especially if it is in the form of small grains in the crucible, so as not to blow away any metal particles. Do not direct the flame at the gold itself: first, gently move the fire over it. Heat the crucible gradually and carefully.

The work takes from 10 minutes or more depending on the quality of the raw materials. After some time, let the gold harden slightly and look at it. If the melt becomes cloudy as it hardens, it means that the process is not over and you need to use the borax again.

When the characteristic yellow sheen stops disappearing upon cooling, melting can be considered complete.

Receiving castings

Molten gold is poured into the prepared mold. It is better if it is made of the same material as the crucible. After a few minutes, when the ingot has cooled a little, you can take it with tongs and lower it into the water.

How to clean castings

After the borax has served its purpose and cleansed the molten gold of excess compounds, you will have to rid the ingot of the remnants of the borax itself. For final cleaning you will need:

• hydrochloric acid - 20 ml,
• nitric acid - 10 ml,
• distilled water - 0.5 l,
• fireproof flask,
• electric stove.

The casting must be boiled in an acid solution for 5 minutes and rinsed with clean water. This part of the experiment is best carried out outdoors, for example in a summer cottage: acid fumes are toxic.

Brass: varieties and melting point

At what temperature does brass melt? Is it worth melting it at home? How does laser cutting of brass occur? These questions were asked by everyone who was faced with the need to make something from an alloy of copper and zinc. The speed of brass melting and the quality of the future product depend on the correctly selected temperature regime. To avoid damage to the material, read the useful information.

Where is brass used?

A non-ferrous metal such as brass is an alloy of copper and zinc (up to 50%) with possible impurities of a small amount of alloying elements. It has high thermal and electrical conductivity, density in the range of 8300-8800 kg/m3 and strength up to 600 MN/m2. Due to these qualities, as well as its attractive golden yellow color, brass is widely used:

• In art. Figurines and busts of famous figures are often made from this material, as it responds well to high temperatures. In addition, in the search for ideal forms, the finished sculpture can always be melted down.
• In interior and exterior design. Stylish light fixtures, mirror frames, and copper and zinc alloy countertops create a 1970s and mid-century modern feel while serving utilitarian functions. To prevent the alloy from blackening when exposed to air, the products are coated with protective compounds.
• In industry. The alloy of copper and zinc has a low coefficient of friction, so it is often used to cover the rubbing surfaces of bearings and other parts; mechanisms for land and water transport, fittings, etc. are made from it. Brass products
• In construction. Bronze and brass are resistant to corrosion, so products made from them can be used in conditions of high humidity. Shut-off and balancing brass fittings are common when installing water pipelines.

Types of brass

Depending on the composition of chemical substances, brasses are divided into:

• Two-component, or simple. Such alloys include mainly copper and zinc, the amount of other elements is insignificant. In turn, among them are:

1. Alpha brass, or single-phase. They contain less than 39% zinc, so there is no need to bring the melting point to 905 °C for it to dissolve into copper.
2. Beta brass, or two-phase. The second phase of brass occurs when the alloy contains more zinc than can be dissolved. As a rule, b-brasses are not as ductile as a-brasses, but are more durable.

classification of brass by chemical composition

• Multicomponent or special. They consist of copper, zinc and alloying elements such as iron, tin, silicon, aluminum, manganese and lead.

According to the degree and quality of brass processing there are:

• Deformable. For the manufacture of parts, such states of deformable brass as extra hard (with compression >50%), hard (with compression >30%), semi-hard (with compression 10-30%) and soft (annealed alloys) are used. A mixture of copper and zinc is presented in the form of round tubes, wire, tapes, sheets.
• Foundries. Cast brass is a low-melting variety that contains at least 50-80% copper, the rest is zinc and alloying elements. This includes the resulting brass products, as well as fittings.

At what temperature does brass melt?

Without knowledge of at what degrees brass melts and how to melt it, it will be impossible not only to cast parts from an alloy of copper and zinc, but also to laser cut brass. An incorrectly selected temperature for processing will lead to deterioration in the quality of the alloy and unnecessary energy consumption.

The melting point of brass is 880-950 °C. This indicator varies depending on the chemical composition of the alloy. The specific heat of fusion of brass does not coincide with the casting temperature. This is especially noticeable when melting lead brasses, which have reduced fluidity. The difference between their melting and casting temperatures is 145-185 °C.

For example, brass grade LS59-1V melts at a temperature of 900 ° C, but casting can be carried out at 1030-1080 ° C. For grades LS59-1 and LS74-3, these figures are 885-895 °C / 1030-1080 °C and 965 ° C / 1120-1160 °C, respectively, etc. For two-component brasses, the melting and casting temperatures are the same.

For example, for L60 it is 885-895 °C, L80 -965-1000 ° C, L96 - 1055-1070 °C.

The specific heat capacity of brass is 380 J/(kg °C). In other words, to heat 380 kg to a temperature of 1 °C, you need to spend 1 J of energy.

processing modes for simple and lead brasses

Please note: the more lead and bismuth in brass, the more difficult it will be to melt. Brass, which contains a large amount of zinc, melts most quickly. Alloys where the amount of this element reaches 32.5% can be processed without heating, using broaching or rolling.

Why is brass melting necessary?

As a rule, brass is melted before it is used to make fittings, condenser pipes, separators, worm screws, bushings, and other parts intended for use at high temperatures (up to 300 degrees Celsius).

Brass is melted to cast railings, cornices, door handles, decorative panels, frames for mirrors and paintings. Kitchen utensils can also be cast from this alloy: teapots, samovars, trays, bread bins, decorative dishes for hanging on the wall.

A mixture of copper and zinc is also useful for making souvenirs and jewelry.

Knowing how to melt brass, you can do this at home. In everyday life, bolsters, backplates, furniture and window fittings, etc. are cast from molten brass.

Melt brass at home

Equipment for melting brass at home is an induction furnace made of refractory materials, a crucible made of graphite or fireclay bricks, a foundry ladle, steel tongs and a volumetric spoon. Before melting the metal, the crucible must be heated for 20-30 minutes at a temperature of at least 95 °C. A spoon is needed to remove slag, tongs are needed to remove the crucible from the furnace, and a ladle is needed to support the crucible when pouring metal.

melting brass at home

To ensure safety, the ground should be covered with an asbestos sheet, and the molten metal should be carried to the molds strictly above the sand box. Special equipment is required. To avoid poisoning by toxic substances, the stove should be placed outdoors or in a well-ventilated area.

When the equipment is ready for use, the material to be melted is crushed and placed in a crucible, which is sent to the furnace. The crucible must remain in the furnace until the metal is completely melted. You can monitor this process through the window if the oven is factory-made, or by periodically lifting the refractory lid if the oven is homemade. Liquid brass is poured into a mold where it must cool before final processing.

You can also melt brass at home using a gas torch. To do this, it is placed under a container containing the crushed alloy. By uniformly heating the bottom of the container, you can achieve a liquid state of the metal.

Please note that during melting it is necessary to prevent the appearance of even small bubbles, which can spoil the quality of the future product. Molten metal cannot be stirred, even while removing slag from its surface.

Is it possible to solder brass?

Many beginners, as a rule, are concerned with the questions: can brass be soldered or not and to how many degrees can it be heated. The answer is clear: you can solder brass. It is quite possible to solder brass surfaces, although it will require more skill than when joining with conventional solder.

Solder for brass should consist of copper and silver, combined in a ratio of 1 to 2. Parts placed on an asbestos base are moistened with flux (borax, boric acid, water), sprinkled with crushed solder, then heated with a gas burner.

The temperature should not exceed 700° C to avoid deformation of parts; heating should be done gradually.

The difference between the melting temperatures of solder and brass parts does not exceed 50 °C, so if overheated, there is a risk of getting a large ingot instead of a quality product. If the work was done efficiently, the seam will have the same color as the brass surface of the part. This is explained by chemical diffusion. The last stage of soldering is removing flux residues. To do this, hot three percent sulfuric acid is used, which is then washed off the product with water.

Source: https://svarkaed.ru/svarka/poleznaya-informatsiya/latun-raznovidnosti-i-temperatura-plavleniya.html

Features, temperatures and methods of melting gold

Many gold buyers wonder why this precious metal is so expensive? But apart from gold's appearance, attractive color and beauty, it has many benefits from a chemical and physical point of view. For example, density, malleability, and the melting point of gold—these are the characteristics of the metal that are used in jewelry, industry, and medicine.

How gold is melted

Properties of gold for which the metal is valued

Gold occurs in nature in the form of grains, particles or nuggets. Therefore, metal requires processing before it gets into banks or stores. The procedure is carried out in factories, but it can also be implemented at home if you know the sequence of stages. Metal processing occurs as follows:

• Mechanical purification of gold from impurities. This happens with the help of water pressure with solutions that additionally wash the gold from dirt and plaque.
• Chemical refining, or refining, of gold, which separates the gold from other metals or ores. Most often, gold is purified from impurities using aqua regia, a mixture of nitric and hydrochloric acids.
• Gold precipitation.
• Metal melting. Manufacturing of ingots, pieces of metal or products of various shapes. For the process, you need to know at what temperature gold melts. Then you can get a product or an ingot from the shapeless precious metal.

In addition, gold has:

High resistance to atmospheric action. It does not corrode, unlike other metals, and does not change appearance over time, even when in the ground. And in the form of jewelry, gold is also difficult to undergo chemical reactions.

Gold is a malleable metal. Its plasticity allows the production of products of various shapes. Gold leaf is thin sheets of precious metal that can be rolled out to a thickness of 0.01 mm and still retain their integrity. On the Mohs softness scale, the precious metal received a value of 2.5–3.0 out of a maximum of ten. This means that pure gold can be scratched even with fingernails.

The density of gold also adds to its value. The metal is 19.3 times denser than water. This property makes it easier to find and launder gold in deposits.

The metal has good electrical conductivity and low resistance. But to use gold on an industrial scale, the costs are too high, and the raw materials in nature are not enough for such purposes.

But gold is sometimes used in microcircuits and sensors to improve contacts. Therefore, a small amount of precious metal can be found if you rummage through old equipment.

And then the question arises: how to melt gold at home and is it possible to do it? In principle, this can be done, especially if the gold is of a lower standard.

Gold nuggets

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Source: https://DedPodaril.com/zoloto/imform/temperatura-plavleniya-zolota.html

At what temperature does metal turn red?

Already in ancient times, people mined and smelted copper. This metal was widely used in everyday life and served as a material for the manufacture of various objects. They learned to make bronze about 3 thousand years ago. This alloy was used to make good weapons. The popularity of bronze quickly spread, as the metal was distinguished by its beautiful appearance and durability. Jewelry, hunting and labor tools, and dishes were made from it. Thanks to the low melting point of copper, people quickly mastered its production.

The metal received its Latin name Cuprum from the name of the island of Cyprus, where they learned to mine it in the third millennium BC. e. In the periodic system, Cu received number 29, and is located in the 11th group of the fourth period.

In the earth's crust, the element is in 23rd place in distribution and is most often found in the form of sulfide ores. The most common are copper luster and pyrite. Today, copper is extracted from ore in several ways, but any technology requires a step-by-step approach to achieve results.

• At the dawn of the development of civilization, people were already obtaining and using copper and its alloys.
• At that time, it was not sulfide ore that was mined, but malachite ore, which did not require pre-roasting.
• A mixture of ore and coals was placed in a clay vessel, which was lowered into a small pit.
• The mixture was ignited, and carbon monoxide helped the malachite to be restored to the state of free Cu.
• There is native copper in nature, and the richest deposits are in Chile.
• Copper sulfides often form in medium-temperature geothermal veins.
• Often the deposits are in the form of sedimentary rocks.
• Copper sandstones and shales are found in Kazakhstan and the Chita region.

Physical properties

The metal is ductile and in the open air it becomes covered with an oxide film in a short time. Thanks to this film, copper has its yellowish-red tint; in the lumen of the film, the color can be greenish-blue. In terms of thermal and electrical conductivity, Cuprum is in second place after silver.

• Density - 8.94×103 kg/m3.
• Specific heat capacity at T=20 ° C - 390 J/kg x K.
• Electrical specific at 20−100 ° C - 1.78×10−8 Ohm/m.
• Boiling point - 2595 ° C.
• Specific electrical conductivity at 20 ° C is 55.5−58 MS/m.

At what temperature does copper melt?

Melting occurs when a metal changes from a solid state to a liquid state. Each element has its own melting point. Much depends on the impurities in the metal . The normal melting point of copper is 1083 ° C. When tin is added, the temperature drops to 930-1140 ° C. The melting point here depends on the tin content of the alloy. In an alloy of cuprum and zinc, melting occurs at 900-1050 ° C.

When any metal is heated, its crystal lattice is destroyed. As it heats up, the melting point increases, but then levels off once a certain temperature limit is reached. At this moment the metal melts. It melts completely and the temperature rises again.

When the metal cools, the temperature decreases, at a certain point it remains at the same level until the metal hardens completely. After complete hardening, the temperature drops again.

This is demonstrated by the phase diagram, which shows the temperature process from the beginning of melting to solidification. When heated, heated copper at 2560 ° C begins to boil. Boiling is similar to the boiling of liquid substances, when gas is released and bubbles appear on the surface.

At the moment of boiling at the highest possible temperatures, the release of carbon formed during oxidation begins.

Melting at home

Due to its low melting point, ancient people could melt cuprum over a fire and use the metal to make various products.

To melt copper at home you will need:

• charcoal;
• crucible and special tongs for it;
• muffle furnace;
• household vacuum cleaner;
• bugle;
• steel hook;
• melting mold.

The process proceeds in stages, the metal is placed in a crucible and then placed in a muffle furnace. The desired temperature is set, and the process is monitored through a glass window. During the process, an oxide film will appear in the container with Cu, which needs to be removed - open the window and move it to the side with a steel hook.

  What metal are the rails made of?

In the absence of a muffle furnace, copper can be melted using an autogenous furnace. Melting will occur if there is normal air access. A blowtorch melts brass and fusible bronze. The flame should cover the entire crucible.

If you don’t have any of the above products at hand, you can use a forge set on a layer of charcoal. To increase T, you can use a vacuum cleaner turned on in the blowing mode, but the hose must have a metal tip, it’s good if it has a narrowed end, so the air stream will be thinner.

The melting point of bronze and brass, like the melting point of copper and aluminum, is low.

Today, Cu is not used in its pure form in industrial settings. It contains many impurities: nickel, iron, arsenic, antimony, and other elements. The quality of the product is determined by the percentage of impurities in the alloy (no more than 1%). Important indicators are thermal and electrical conductivity. Due to its ductility, low melting temperature and flexibility, copper is widely used in many industries.

Source: http://ooo-asteko.ru/pri-kakoy-temperature-metall-krasneet/

Optimal melting temperature of steel

Each individual metal has a number of individual physical and chemical properties that determine the scope of its application. The melting method allows you to create products of different shapes from the material. To manufacture steel structures, it is necessary to know the melting point of steel.

Melting point of steel

• Metal classification
• Calculation principle
• How does the process work?

Metal classification

Man has long known the melting temperatures of metals and alloys. Thanks to this data, they can be divided into three large groups:

1. Low-melting metals - melt up to 600 degrees Celsius. These include tin, zinc, and lead.
2. Medium melting - melts in the range of 600-1600 degrees Celsius. The most extensive group, which includes all possible alloys and homogeneous materials.
3. Refractory - melts at 1600 degrees Celsius. These include titanium, chromium, molybdenum, tungsten.

To find out more accurate information, you can study the table of melting temperatures of metals. You can find it on the Internet or special reference books for foundry workers. If we talk about alloys, their heat of fusion will depend on the amount of impurities contained in the composition.

Calculation principle

Previously, Lindemann's formula was used to calculate the melting point of a metal. However, due to the low accuracy of the final calculations, it did not gain much popularity among foundries. In 1999, I.V. Gavrilin proposed a new system for calculating boiling and melting points:

Tm = DHm / 1.5 N0 k,

Explanation:

1. Tmelting temperature.
2. DHmelt - indicates the latent melting point.
3. N0 is the designation of the latent heat of melting.
4. k — Designation of Boltzmann's constant.

How does the process work?

To carry out the melting process, it is necessary to know not only the melting temperature of steel, but also to use industrial equipment. The technology consists of three main stages:

1. Melting rock. This stage involves remelting the charge until a bath of molten metal is formed. It is important that phosphorus is removed from the resulting bath. To do this, the slag must contain iron oxide. Temperatures should not reach critical levels.
2. The next stage is boiling the molten charge bath. To boil the liquid mass, the temperature increases. In this case, carbon is intensively oxidized. If it does not oxidize, the technological process will stop. To make the process more intense, pure oxygen is blown into the bath.
3. The third stage is metal deoxidation. This process is needed to reduce the amount of oxygen in the molten mass. For this, two methods can be used - precipitation, diffuse. The first is the addition of ferromanganese, ferrosilicon, and aluminum to the molten mass. The second method is identical to the first.

To improve the quality of steel, the molten mass is further processed after it is poured out of the furnace. For this purpose, blowing with argon is carried out.

Optimal melting temperature of steel Link to main publication

Source: https://metalloy.ru/stal/temperatura-plavleniya

At what temperature does steel melt - Metalworker's Handbook

Steel is an alloy of iron mixed with carbon. Its main benefit in construction is strength, because this substance retains its volume and shape for a long time. The whole point is that the particles of the body are in a position of equilibrium. In this case, the attractive and repulsive forces between the particles are equal. The particles are in a clearly defined order.

• Melting temperatures of steel
• Stainless steel
• Cast iron and steel

There are four types of this material: regular, alloy, low-alloy, high-alloy steel. They differ in the number of additives in their composition. The usual one contains a small amount, and then increases. The following additives are used:

• Manganese.
• Nickel.
• Chromium.
• Vanadium.
• Molybdenum.

Melting temperatures of steel

Under certain conditions, solids melt, that is, they turn into a liquid state. Each substance does this at a certain temperature.

• Melting is the process of transition of a substance from a solid to a liquid state.
• Melting point is the temperature at which a crystalline solid melts into a liquid state. Denoted by t.

Physicists use a specific table of melting and crystallization, which is given below:

Substance	t,°C	Substance	t,°C	Substance	t,°C
Aluminum	660	Copper	1087	Alcohol	— 115
Voden	— 256	Naphthalene	80	Cast iron	1200
Tungsten	3387	Tin	232	Steel	1400
Iron	1535	Paraffin	55	Titanium	1660
Gold	1065	Mercury	— 39	Zinc	420

Based on the table, we can safely say that the melting point of steel is 1400 °C.

Stainless steel

Stainless steel is one of the many iron alloys found in steel. It contains Chromium from 15 to 30%, which makes it rust-resistant, creating a protective layer of oxide on the surface, and carbon. The most popular brands of this type are foreign. These are the 300th and 400th series.

They are distinguished by their strength, resistance to adverse conditions and ductility. The 200 series is of lower quality, but cheaper. This is a beneficial factor for the manufacturer.

Its composition was first noticed in 1913 by Harry Brearley, who conducted many different experiments on steel.

At the moment, stainless steel is divided into three groups:

• Heat-resistant - at high temperatures it has high mechanical strength and stability. The parts that are made from it are used in the pharmaceutical, rocketry, and textile industries.
• Rust-resistant - has great resistance to rusting processes. It is used in household and medical devices, as well as in mechanical engineering for the manufacture of parts.
• Heat-resistant - resistant to corrosion at high temperatures, suitable for use in chemical plants.

The melting point of stainless steel varies depending on its grade and the number of alloys from approximately 1300 °C to 1400 °C.

Cast iron and steel

Cast iron is an alloy of carbon and iron, it contains impurities of manganese, silicon, sulfur and phosphorus. Withstands low voltages and loads. One of its many advantages is its low cost for consumers. There are four types of cast iron:

• White - has high strength and poor ability to be processed with a knife. Types of alloy according to the increase in the amount of carbon in the composition: hypoeutectic, eutectic, hypereutectic. It was called white due to the fact that it has a white color in the fault. White cast iron also has a special structure of the metal mass and great wear resistance. Useful in making mechanical parts that will operate in a non-lubricated environment. It is used to make the following types of cast iron.
• Gray cast iron - contains carbon, silicon, manganese, phosphorus and some sulfur. It can be easily obtained and has poor mechanical properties. Used for the manufacture of parts that are not exposed to shock loads. There is a gray color in the fracture; the darker it is, the softer the material. The properties of gray cast iron depend on the temperature of the environment in which it is located and the amount of various impurities.
• Malleable cast iron is obtained from white cast iron as a result of simmering (prolonged heating and holding). The substance contains: carbon, silicon, manganese, phosphorus, and a small amount of sulfur. It is more durable and ductile, easier to process.
• Ductile iron is the strongest of all types of cast iron. Contains carbon, manganese, sulfur, phosphorus, silicon. Has high impact strength. This important metal is used to make pistons, crankshafts and pipes.

The melting points of steel and cast iron are different, as stated in the table above. Steel has higher strength and resistance to high temperatures than cast iron, temperatures differ by as much as 200 degrees. For cast iron, this number ranges from approximately 1100 to 1200 degrees, depending on the impurities it contains.

Source: https://ssk2121.com/pri-kakoy-temperature-plavitsya-stal/

Refractory metals - description, products made from refractory metals

The definition of “refractory metals” does not require additional explanation due to the exhaustive information content of the term itself. The only nuance remains the threshold melting temperature, after which the substance can be considered refractory.

Disagreement on a Critical Parameter

Some sources set the threshold value as 4000 F. Translated to the usual scale, this gives 2204 0C. According to this criterion, only five elements are considered heat-resistant: tungsten, niobium, rhenium, tantalum and molybdenum. For example, the melting point of tungsten is 3422 0C.

melting tungsten with a hydrogen torch

Another statement allows us to expand the class of temperature-resistant materials, since it takes the melting point of iron as the starting point - 1539 0C. This allows the list to be expanded by nine more elements to include titanium, vanadium, chromium, iridium, zirconium, hafnium, rhodium, ruthenium and osmium.

There are several other temperature thresholds, but they are not widely used.

Comparative table of the degree of refractoriness of pure metals

It should be noted that refractory materials are not limited solely to metals. This category includes a number of compounds - alloys and alloy metals - designed to improve certain characteristics of the original material.

Regarding pure elements, we can give a visual table of the degree of their temperature stability. It is headed by the most refractory metal known today - tungsten with a melting point of 3422 0C. This cautious formulation is associated with attempts to isolate metals that have a melt threshold that exceeds tungsten.

Therefore, the question of which metal is the most refractory may in the future receive a completely different definition.

The threshold values ​​for the remaining compounds are given below:

• rhenium 3186;
• osmium 3027;
• tantalum 3014;
• molybdenum 2623;
• niobium 2477;
• iridium 2446;
• ruthenium 2334;
• hafnium 2233;
• rhodium 1964;
• vanadium 1910;
• chrome 1907;
• zirconium 1855;
• titanium 1668.

It remains to add one more interesting fact concerning the physical properties of heat-resistant elements. The melting point of some of them is sensitive to the purity of the material. A striking example of this is chromium, the melting point of which can vary from 1513 to 1920 0C, depending on the chemical composition of the impurities. Therefore, these Internet spaces often differ in exact numbers, but the quality component does not suffer from this.

Pure chrome

General properties of heat-resistant materials

The relative similarity of the physicochemical characteristics of these elements is due to the common atomic structure and the fact that they turn out to be transition metals. On the contrary, differences in properties are associated with their belonging to a wide range of groups of the Periodic Table: IV – VII.

The basic general characteristic of refractory materials is strong interatomic bonds. Their rupture requires high energy, which determines the melting temperature of thousands of degrees Celsius. Additionally, this property affects the high values ​​of such parameters of refractory metals as: hardness, mechanical strength, electrical resistance.

The next characteristic that unites these elements is high chemical activity. It is associated with the general tendency of refractory metals to form chemical bonds through a free p- and partially filled d-orbital, donating electrons from the outer s and d levels. This property makes it difficult to obtain pure refractory metals, dividing the technological production into several stages.

The structure of the heat-resistant elements is also identical; they are all characterized by a body-centered cubic crystal lattice. This structure is characterized by “brittleness.” The exception is rhenium, which has a hexagonal cell. The transition to a brittle state for each metal occurs at a certain temperature, the regulation of which is achieved through alloying.

Every refractory metal is, by definition, heat-resistant, but not all of them are heat-resistant. Most refractory metals are resistant to oxidation and aggressive environments: acids, alkalis; under normal conditions.

However, with an increase in temperature to 400 0C, their activity increases abnormally. This requires the creation of certain operating conditions.

Therefore, products made of refractory metals, at elevated temperatures of use, are often placed in an atmosphere of inert gases or the air is rarefied to vacuum conditions.

Obtaining refractory materials

As noted earlier, the main obstacle to the production of heat-resistant metals is their high chemical activity, which prevents the release of elements in their pure form.

The main production technology remains powder metallurgy. This technique makes it possible to obtain powders of refractory metals in various ways:

1. Reduction with hydrogen trioxide. The process is carried out in several stages, inside multi-tube furnaces at 750 – 950 °C. The technology is applicable for powders of refractory metals: tungsten and molybdenum.
2. Reduction of perrhenate with hydrogen. The scheme is implemented in the production of rhenium metal. Operating temperatures are around 500 °C. The final stage involves washing the powder from the alkali. To do this, hot water and a solution of hydrochloric acid are used sequentially.
3. Use of metal salts. Technology has been developed to isolate molybdenum. The main raw materials are the ammonium salt of the metal and its metal powder, introduced into the mixture at a level of 5 - 15% by weight. The composition undergoes heat treatment at 500 – 850 °C in flowing inert gas. The reduction of the metal takes place in a hydrogen atmosphere at temperatures of 800 – 1000 °C.

Production of refractory metals - powder metallurgy

Excursion to production

Methods for producing heat-resistant metals continue to be improved, as does the chemical technology of refractory non-metallic and silicate materials, which is associated with the development of nuclear energy, aircraft construction, and the emergence of new models of rocket engines.

One of the largest tungsten production enterprises in the Russian Federation is the Unech Refractory Metals Plant. This enterprise is relatively young; its construction began in 2007 on the territory of the settlement of Unecha. The plant's production focus is on powders of refractory metals, more precisely tungsten and its carbides.

Subsequently, to obtain ingots, the crumbly mass is sintered or compressed with a press. In a similar way, refractory metal powders are processed to produce heat-resistant products.

Application of refractory materials

The use of pure heat-resistant metals has priorities in a number of areas:

• production of spacecraft;

• production of guided missiles, missiles;

• electronic and vacuum technology.

Space industry

The last point concerns the electrodes of vacuum tubes. For example, high-purity niobium is used to produce meshes and tubes for electronic parts. It is also used to make electrodes - anodes of electric vacuum devices.

Electrovacuum radio tubes

Similar applications are typical for molybdenum and tungsten. These metals in their pure form are used not only as filaments, but also for electrodes of radio tubes, hooks, and pendants of electric vacuum equipment. Tungsten single crystals, on the contrary, are used as heaters for electrodes, in particular cathodes, and also in the manufacture of electrical contacts and fuses.

Pure vanadium and niobium are used in nuclear energy, where they are used to make pipes for nuclear reactors and shells of fuel elements. The area of ​​application of high-purity tantalum is chemistry (ware and equipment), since the metal is highly resistant to corrosion.

Refractory solder should be considered separately, since it does not include metals with high melting points. For example, refractory tin does not contain refractory metal powders. Copper, silver, nickel or magnesium are used as additives here.

Refractory metals and alloys are in demand both in rolled products and in other areas. In particular, the use of alloys is due to the ability to modify certain properties of the metal: lower the embrittlement temperature, improve heat-resistant characteristics.

Rolled products from refractory metals are quite wide in range and include:

• regular and deep-drawing strips;

Tungsten-rhenium thermoelectrode wire

The largest domestic manufacturer of this type of product is an experimental plant for refractory metals and hard alloys.

refractory metals

Source: http://xlom.ru/spravochnik/tugoplavkie-metally-opisanie-izdeliya-iz-tugoplavkix-me/

Melting temperature, properties and independent melting of cast iron

Cast iron is an alloy based on iron and carbon. It differs from steel in the latter content – ​​2% or more. Some brands contain up to 4% carbon. Most often, an alloy with a carbon content of 3-3.5% is used.

This is a casting material. For such a metal, such properties as its melting point, as well as its thermal properties - heat capacity, thermal conductivity, thermal diffusivity - come to the fore. How different chemical elements affect the quality of this metal and whether it is possible to melt it yourself - this will be discussed in the article.

Thermal properties of cast iron

An important category of physical properties of a material is its thermal properties. These include:

• Heat capacity.
• Thermal conductivity.
• Thermal diffusivity.
• Thermal expansion coefficient.

They all depend on the composition, structure, and therefore on the grade of the alloy. In addition, these properties of the metal change with changes in its temperature (the so-called displacement rule). The nature of this dependence and the main physical properties are given in the table.

Heat capacity (s)

This is the amount of heat that must be supplied to the body in order for its temperature to increase by one Kelvin (hereinafter all values ​​are converted to degrees Celsius).

The heat capacity depends on the composition of the alloy, as well as on temperature (T). The higher T, the greater the heat capacity. If the temperature is above T for phase transformations, but below T for melting, then

c = 0.18 cal/(G˚С)

at T exceeding the melting point:

c = 0.23±0.03 cal/(G˚С)

Volumetric heat capacity (the ratio of heat capacity to the volume of a substance) for approximate calculations is accepted:

• cast iron in solid state c' = 1 cal/(cm3G˚C)
• molten c' = 1.5 cal/(cm3G˚C)

Thermal conductivity (λ)

This is a quantitative characteristic of a body's ability to conduct heat. The displacement rule does not apply to thermal conductivity. The temperature of the material increases – λ decreases. It depends on the composition of the alloy, and to a greater extent on its structure. Substances that increase the degree of graphitization increase thermal conductivity, and substances that prevent the formation of graphite decrease it.

By the way, the thermal conductivity of molten cast iron is much less than that of solid cast iron. But due to convection it is greater than λ of the solid metal.

Thermal conductivity for different brands lies within:

λ =0.080.13 cal/ (cm·sec oC)

Thermal conductivity and other thermophysical properties depending on the temperature of the alloy are given at the end of the section.

Thermal diffusivity (α)

This is a physical quantity that shows how quickly body temperature changes. Equal to the ratio of thermal conductivity to volumetric heat capacity.

For approximate calculations you can take:

α=λ for solid metal (equal to its thermal conductivity);

α=0.03 cm2/sec for liquid.

Melting temperature

This alloy has good casting properties. Better than steel. The fluidity is high and the shrinkage is low (about 1%). It can be melted at a temperature 300-400 degrees lower than steel. Cast iron melting point:

What is it like?

The structure of cast iron is an iron base with graphite (carbon) inclusions. This material is distinguished not by its composition, but by the form of carbon in it:

• White cast iron (BC). Contains carbide (cementite) - this is a form of carbon, the same as in steel. It has a whitish color when scrapped. Very hard and brittle. In its pure form it is almost never used.
• Gray cast iron (GC). Contains carbon in the form of flake graphite. Such inclusions have a bad effect on the quality of the material. To change the shape of graphite grains, there are special methods of melting and further processing. Graphite in midrange can also be in the form of fibers (“worm-shaped” form) - the so-called vermicular graphite (from the Latin word vermiculus - a worm, like vermicelli).
• Highly durable. Spherical shape of graphite grains. It is obtained by introducing magnesium into the alloy.
• Malleable cast iron. To obtain it, warheads are annealed. Graphite grains in the form of flakes.

As a result, the main difference between it (apart from white) and steel is the presence of a graphite structure. And different forms of graphite determine the properties of different grades.

Conventionally, graphite grains are voids and cracks, and cast iron is steel riddled with microscopic cracks.

Accordingly, the more voids, the worse the quality of the metal. The shape and relative position of the inclusions also matters.

However, graphite grains should not be accepted as exclusively harmful. Due to the presence of graphite, this material is easier to machine and the chips become more brittle. In addition, it resists friction well also due to the graphite.

Impurities

Of course, this metal contains more than just iron and carbon. It contains the same elements as steel alloys - phosphorus, manganese, sulfur, silicon and others. These additives indirectly affect the characteristics of the alloy - they change the course of graphitization. The quality of the material depends on this parameter.

• Phosphorus. Has little effect on the formation of graphite. But it is still needed, because it improves fluidity. Solid inclusions of phosphorus provide high hardness and wear resistance of the metal.
• Manganese. It interferes with graphitization and, as it were, “bleaches” cast iron.
• Sulfur. Like silicon, it promotes bleaching of the metal, and also impairs fluidity. The amount of sulfur in the alloy is limited. For small castings no more than 0.08%, for parts more - up to 0.1-0.12%.
• Silicon. Strongly affects the properties of the material, increasing graphitization. The metal can contain from 0.3-0.5 to 3-5% silicon. By varying the amount of silicon, an alloy with different properties is obtained - from white to high-strength.
• Magnesium. Helps to obtain material with spherical grain shape. The boiling point of magnesium is low (1107˚C). For this and other reasons, introducing magnesium into the alloy is difficult. To avoid its boiling, the material is smelted using various methods of introducing magnesium.

In addition to the usual impurities, cast iron may contain other substances. This is the so-called alloyed material. Chromium, molybdenum, vanadium interfere with the process of graphite formation. Copper, nickel and most other substances contribute to graphitization.

Self-smelting technology

Non-industrial smelting of cast iron is a very labor-intensive process. It is impossible to smelt factory-quality castings with your own hands in artisanal conditions.

You cannot smelt this metal at home. You need a separate ventilated room - a garage, for example. Melting is carried out in furnaces. In industry, blast furnaces, cupola furnaces and induction furnaces are used.

A blast furnace is an industrial unit capable of melting metal on a huge scale. Iron ore raw materials can be smelted in it. After launch, it works without interruption for up to 5-6, or even up to 10 years. Then it is stopped, serviced and started again. Melting of the metal takes place in the presence of gases to improve the quality of the material. Such ovens are not suitable for small and medium-sized production. Fuel - coke.

A cupola furnace is a shaft-type furnace, like a blast furnace. It differs from the latter in that it does not maintain a special composition of gases. It is not ore that is smelted in it, but scrap iron. It is more suitable for small production.

An induction furnace is a modern type of equipment. The smelting process in such a furnace can be controlled, temperature, heating time and charge composition can be adjusted.

Melting is carried out in crucibles made of refractory clay or brick. Steel ones are not suitable, although steel begins to melt at a temperature higher than cast iron. Flux is required - a substance that promotes the formation of low-melting slag. For example, limestone (CaCO3), fluorspar (CaF2). To obtain gray rather than white cast iron, ferrosilicon (an alloy of iron and silicon) is added to the charge. It improves the formation of graphite grains. Once melted, the metal is poured into a sand or metal mold.

Metal casting is an explosive and fire hazardous job. In addition, it is necessary to have certain knowledge in the field of metallurgy. To organize production, you will need to complete documentation, pass inspections, obtain permission and a license to work.

We also recommend reading:

Classification of cast iron and its types

Source: https://oxmetall.ru/metalli/chugun/temperatura-plavleniya

Refractory metals

Refractory metals were allocated into a separate class due to the property that unites them - a high melting point. It is higher than that of iron, which is 1539 °C. Therefore, the metals of this group received such a name. They belong to the so-called rare earth elements. For example, in terms of abundance in the earth’s crust, niobium and tantalum account for 3%, and zirconium only 2%.

Refractory metals

According to the melting temperature indicator, in addition to those listed, these include metals of the so-called platinum group. They are also called noble or precious.

A certain similarity in the structure of the atom determined the similarity of their properties. Based on this, it is possible to summarize some of the features of the manifestation of such metals in the earth’s crust and determine the technology for their extraction, production and processing.

Properties of refractory metals

Due to the fact that they are located in adjacent groups of the periodic table, the physical properties of refractory metals are quite similar:

• The density of the metal ranges from 6100 to 10000 kg/m3. In terms of this indicator, only tungsten stands out. For him it is equal to 19000 kg/m3.
• Melting temperature. It exceeds the melting point of iron and ranges from 1950 °C for vanadium to 3395 °C for tungsten.
• Their specific heat capacity differs slightly from each other and ranges from 200 to 400 J/(kg-deg).
• The thermal conductivity coefficient varies greatly from element to element. If for vanadium it is 31 W/(m-deg), then for tungsten it reaches a value of 188 W/(m-deg).

Physical properties of refractory metals

The chemical properties are also quite similar:

• Very similar atomic structure.
• They have high chemical activity. This property determines the main difficulties in maintaining the stability of their compounds.
• The strength of interatomic bonds determines the high melting point. This circumstance explains the high mechanical strength, hardness and electrical characteristics (in particular resistance).
• Show good resistance to various acids.

The main disadvantages of refractory metals include:

• Low corrosion resistance. The oxidation process occurs quite quickly. It is divided into two successive stages. Direct interaction of the metal with oxygen in the surrounding air, which leads to the formation of an oxide film. At the second stage, the process of diffusion (penetration) of oxygen atoms through the formed oxide film occurs.
• Difficulties with weldability of refractory metals. This is caused by high chemical reactivity to the surrounding air at high temperatures, fragility when saturated with various impurities. In addition, it is difficult to determine the overheating point and almost impossible to control the increase in yield strength.
• Difficulties in obtaining them for use in their pure form without impurities.
• The need to use special coatings to prevent rapid oxidation. Silicide coatings have been developed for alloys based on tungsten and molybdenum.
• Difficulties associated with machining. For high-quality processing, they must first be heated.

Production of refractory metals

All methods for producing refractory metals are based on the methods of so-called powder metallurgy. The process itself occurs in several stages:

1. At the initial stage, metal powder is obtained.
2. The required metal is then isolated by chemical reduction methods (usually ammonium salts or oxides). This release occurs as a result of exposure of the powder to hydrogen.
3. At the final stage, a chemical compound called hexafluoride of the corresponding metal is obtained, and from it the metal itself is obtained.

Application of refractory metals

Starting from the second half of the twentieth century, refractory metals began to be used in many branches of industrial production. Powders of refractory metals are used for the production of primary products. Refractory metals are produced in the form of wire, ingots, fittings, rolled metal and foil.

Such metals occupy a special place in the technology of growing leucosapphires. They belong to the class of single crystals and are called artificial rubies.

Products made of refractory metals are included in household and industrial electrical appliances, fire-resistant structures, and parts for engines of aviation and space technology. Refractory metals occupy a special place in the production of parts with complex configurations.

This metal was discovered back in 1781. Its melting point is 3380 °C. Therefore, it is by far the most refractory metal. Tungsten is obtained from a special powder by subjecting it to chemical treatment. This process is based on pressing followed by sintering at high temperatures. Next, it is subjected to forging and drawing on machines. This is due to its greatest refractoriness.

This is how a fibrous structure (wire) is obtained. It is quite durable and practically does not break. At the final stage, it is rolled out into thin threads or flexible tape. To carry out mechanical treatment, it is necessary to create a protective environment of inert gas. In this environment the temperature must exceed 400 °C. At ambient temperatures it acquires paramagnetic properties.

It has the following disadvantages:

• difficulty in creating conditions for mechanical processing;
• rapid formation of oxide films on the surface. If there are sulfur-containing substances in contact, sulfide films are formed;
• creating good electrical contact between several parts is only possible when creating high pressure.

Tungsten

To improve the properties of tungsten (refractoriness, corrosion resistance, wear resistance), alloying metals are added to it. For example, rhenium and thorium.

The metal is used to produce filaments for lighting and drying lamps. It is added to welding electrodes, elements of electron lamps and X-ray tubes. It is also used in the production of rocket elements, jet engines, and artillery shells.

In appearance and characteristics it is very similar to tungsten. The main difference is that its specific gravity is almost two times less. It is obtained in a similar way. It is widely used in the electronics industry, for the manufacture of various evaporators in vacuum technology, and breaking electrical contacts. Like tungsten, it is paramagnetic. It is simply irreplaceable for the manufacture of electrodes for glass melting furnaces.

Niobium

The melting point of niobium is 2741 °C. In its chemical, physical and mechanical properties it is very similar to tantalum. It is quite flexible. It has good weldability and high thermal conductivity even without additional heating. Like all other metals, it is obtained from powder. Final niobium workpieces - wire, tape, pipe.

Niobium

The metal itself and its alloys demonstrate the effect of superconductivity. It is widely used for the manufacture of anodes, screen and anti-dynatron grids in electric vacuum devices. Due to its good porosity, it is successfully used as a gas absorbent. In microelectronics, it is used to make resistors in microcircuits.

Niobium has proven itself well as an alloying additive. It is used to create various heat-resistant structures and units operating in aggressive and radioactive environments. Some elements of jet engines are made from an alloy of steel and niobium. Due to its property of not interacting with radioactive substances at high temperatures, for example, uranium, it is used in the manufacture of shells for uranium elements that remove heat in reactors.

Tantalum

Externally it has a light gray color with a slight bluish tint. The melting point is close to 3000 °C. Amenable to basic types of processing. It can be forged, rolled, and drawn to make wire.

These operations do not require significant heating. For ease of further use, tantalum is produced in the form of foil and thin sheets.

An increase in temperature causes active interaction with all gases, except inert ones - no reactions are observed with them.

Tantalum

Tantalum is used to produce the internal elements of generator tubes (magnetrons and klystrons). It is actively used in the production of plates in electrolytic capacitors. Very convenient for making film resistors. It is actively used for the manufacture of so-called boats in evaporators, in which thermal spraying of various materials is carried out on thin films.

Due to a number of its unique qualities, it is considered indispensable in the nuclear, aerospace and radio-electronic industries.

Rhenium

It was discovered later than all of the previously listed metals. It fully lives up to its name "rare earth metal" because it is found in small quantities in the ore of other metals such as platinum or copper.

It is mainly used as an alloying additive. The resulting alloys acquire good strength and ductility characteristics. This is one of the most expensive metals, so its use leads to a sharp increase in the price of all equipment.

However, it is used as a catalyst.

Chromium

Chrome is a unique metal. It is widely used in industry due to its remarkable properties: strength, resistance to external influences (heat and corrosion), ductility. A fairly hard but brittle metal. It has a steel-gray color. All the chromium needed is extracted from the ore of two types of iron chromite or chromium oxide.

Its main properties are:

• Even at normal temperature it has almost perfect antiferromagnetic ordering. This gives it excellent magnetic properties.
• Reacts differently to exposure to hydrogen and nitrogen. In the first case, it retains its strength. In the second, it becomes brittle and completely loses all its plastic properties.
• It is highly resistant to corrosion. This happens due to the fact that when interacting with oxygen, a thin protective film is formed on the surface. It serves to protect against further corrosion.

Chromium crystals

It is used in the metallurgical, chemical, and construction industries. Chromium, as an alloying additive, is necessarily used for the production of various grades of stainless steel. It occupies a special place in the manufacture of such material as nichrome.

This material can withstand very high temperatures. Therefore, it is used in various heating elements. Chrome is actively used to cover the surfaces of various parts (metal, wood, leather). This process is carried out using electroplating.

The toxicity of some chromium salts is used to preserve wood from damage and the harmful effects of fungi and mold. They are also good at repelling ants, termites, and insects that destroy wooden structures. Chromium salts are used to treat the skin. Chromium is used in the manufacture of various dyes.

Due to its high heat resistance, it is used as a refractory material for blast furnaces. The catalytic properties of chromium compounds are successfully used in the processing of hydrocarbons. It is added when producing the highest quality magnetic tapes. It provides low noise figure and wide bandwidth.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/tugoplavkie-metally.html