What is an alloy?

Alloys, their classification and properties

There are several ways to classify alloys:

• by manufacturing method (cast and powder alloys);
• by the method of obtaining the product (casting, wrought and powder alloys);
• by composition (homogeneous and heterogeneous alloys);
• according to the nature of the metal - base (ferrous - Fe base, non-ferrous - base, non-ferrous metals and alloys of rare metals - radioactive elements base);
• by the number of components (double, triple, etc.);
• by characteristic properties (refractory, low-melting, high-strength, heat-resistant, hard, anti-friction, corrosion-resistant, etc.);
• by purpose (structural, instrumental and special).

Properties of alloys

The properties of alloys depend on their structure. Alloys are characterized by structure-insensitive (determined by the nature and concentration of the elements that make up the alloys) and structure-sensitive properties (depending on the characteristics of the base). The structurally insensitive properties of alloys include density, melting point, and heat of evaporation. thermal and elastic properties, coefficient of thermal expansion.

All alloys exhibit properties characteristic of metals: metallic luster, electrical and thermal conductivity, ductility, etc.

Also, all the properties characteristic of alloys can be divided into chemical (the relationship of alloys to the effects of active media - water, air, acids, etc.) and mechanical (the relationship of alloys to the effects of external forces).

If the chemical properties of alloys are determined by placing the alloy in an aggressive environment, then special tests are used to determine the mechanical properties.

So, in order to determine strength, hardness, elasticity, ductility and other mechanical properties, tensile, creep, impact strength, etc. tests are carried out.

Main types of alloys

Various steels, cast iron, alloys based on copper, lead, aluminum, magnesium, as well as light alloys are widely used among all kinds of alloys.

Steels and cast irons are alloys of iron and carbon, with the carbon content in steel up to 2%, and in cast iron 2-4%. Steels and cast irons contain alloying additives: steels – Cr, V, Ni, and cast iron – Si.

There are different types of steels; for example, structural, stainless, tool, heat-resistant and cryogenic steels are distinguished according to their intended purpose. Based on their chemical composition, they are divided into carbon (low-, medium- and high-carbon) and alloyed (low-, medium- and high-alloy). Depending on the structure, austenitic, ferritic, martensitic, pearlitic and bainitic steels are distinguished.

Steels have found application in many sectors of the national economy, such as construction, chemical, petrochemical, environmental protection, transport energy and other industries.

Depending on the form of carbon content in cast iron - cementite or graphite, as well as their quantity, several types of cast iron are distinguished: white (light color of the fracture due to the presence of carbon in the form of cementite), gray (gray color of the fracture due to the presence of carbon in the form of graphite ), malleable and heat resistant. Cast irons are very brittle alloys.

The areas of application of cast iron are extensive - artistic decorations (fences, gates), cabinet parts, plumbing equipment, household items (frying pans) are made from cast iron, and it is used in the automotive industry.

Copper-based alloys are called brasses; they contain from 5 to 45% zinc as additives. Brass containing 5 to 20% zinc is called red (tompak), and brass containing 20–36% Zn is called yellow (alpha brass).

Among lead-based alloys, two-component (lead alloys with tin or antimony) and four-component alloys (lead alloys with cadmium, tin and bismuth, lead alloys with tin, antimony and arsenic) are distinguished, and (typical of two-component alloys) with different contents of the same components different alloys are obtained. Thus, an alloy containing 1/3 lead and 2/3 tin - tertiary (ordinary solder) is used for soldering pipes and electrical wires, and an alloy containing 10-15% lead and 85-90% tin - pewter, was previously used for casting cutlery.

Aluminum-based two-component alloys – Al-Si, Al-Mg, Al-Cu. These alloys are easy to produce and process. They have electrical and thermal conductivity, are non-magnetic, harmless in contact with food, and explosion-proof.

Aluminum-based alloys are used for the manufacture of lightweight pistons; they are used in carriage, automobile and aircraft construction, the food industry, as architectural and finishing materials, in the production of technological and household cable ducts, and in the laying of high-voltage power lines.

Examples of problem solving

Source: http://ru.solverbook.com/spravochnik/ximiya/9-klass/splavy/

Chemical alloys

It is known that metals are rarely used in their pure form. Most often we are surrounded by various metal compounds and their alloys. Alloys are substances consisting of chemical elements, one of which is a metal.

Preparation of alloys

It was noticed a long time ago that if you mix molten metals and cool the resulting mixture, you get a substance whose properties differ from the properties of each of the metals. So, if aluminum is added to molten copper, then as a result of a chemical reaction a new compound with the formula AlCu is obtained.

Alloys are obtained in various ways. If the molten components are mixed and then the resulting melt is crystallized, a cast alloy is obtained. Crystallization is the process of transition from a liquid to a solid state.

In this case, a compound with a crystalline structure is formed. And if the powders of the components are mixed, and then the mixture is sintered at high temperature, an alloy is obtained, which is called a powder alloy.

To improve properties, elements called alloying elements are introduced into alloys.

Types of alloys

Alloys can contain only metals or compounds of metals with non-metals. The alloy usually gets its name from the name of the element that is contained in the alloy in the largest quantity and forms the basis of the alloy. So, if the base of the alloy is iron, then the alloys are called ferrous. And if the basis of the alloys is non-ferrous metals, then the alloys are called non-ferrous. There are also alloys of rare metals and alloys of radioactive metals.

Ferrous alloys

Alloys can have two or more components.

The most famous ferrous alloys are steel and cast iron. Both of these alloys are a mixture of iron and carbon. But cast iron contains much more carbon than steel. In addition to carbon, cast iron contains sulfur, phosphorus, manganese and silicon. These elements are also added to steel, but in much smaller quantities. Cast iron is a brittle material.

It is used where forging is not required. But steel is not only durable, but also a ductile material. Therefore, it is widely used in industry in metal structures, mechanisms, parts, for the manufacture of cutting tools, etc.

In our home we are surrounded by stainless steel products: knives, forks, spoons, scissors, graters, pots.

Non-ferrous alloys

The most famous copper alloys are bronze and brass.

An alloy of copper and tin is called bronze. In the 3rd millennium BC, tools were made from copper, since copper deposits at that time were huge. It turned out that if copper is combined with tin, a substance is obtained that is more amenable to casting. This is how bronze was obtained for the first time. The next millennium was called the “Bronze Age”. In the 15th century Guns began to be cast from bronze. Nowadays, bronze is used in mechanical engineering for the manufacture of various parts.

Brass is an alloy of copper and zinc. Used in the production of equipment, the automotive industry, and the chemical industry. Interestingly, brass is similar in appearance to gold. Therefore, until the 19th century, it was often passed off as gold.

The combination of copper and aluminum is called aluminum bronze. Aluminum bronze is a very ductile material.

Cupronickel is an alloy of copper and nickel. Used to make cutlery and art products.

The well-known aluminum alloy duralumin is a compound of aluminum with copper, magnesium and manganese. Used in the aviation industry and aircraft construction.

Magnesium, titanium, and beryllium alloys also find their use in industry and medicine.

Metals and alloys play a very important role in various types of human activity. It is impossible to list all the areas in which metals and their alloys are used.

Source: http://ximik.biz/prakticheskaya-himiya/55-himicheskiye-splavy

Metal alloys

Metals have been used by humans for many millennia. The defining eras of human development are named after the names of metals: the Bronze Age, the Iron Age, the Age of Cast Iron, etc. Not a single metal product around us consists of 100% iron, copper, gold or other metal. Each contains additives deliberately introduced by a person and harmful impurities introduced against the will of a person.

Absolutely pure metal can only be obtained in a space laboratory. All other metals in real life are alloys - solid compounds of two or more metals (and non-metals), purposefully obtained in the process of metallurgical production.

Classification of homogeneity of alloys

Classification

Metallurgists classify metal alloys according to several criteria:

1. manufacturing method:
2. production technology:
   • foundries;
   • deformable;
   • powder;
3. homogeneity of structure:

   Types of alloys based on them

4. type of metal - basics:
   • black (iron);
   • non-ferrous (non-ferrous metals);
   • rare metals (radioactive elements);
5. number of components:
   • double;
   • triple;
   • and so on;
6. physicochemical characteristics:
   • refractory;
   • fusible;
   • high strength;
   • heat resistant;
   • hard;
   • antifriction;
   • corrosion-resistant, etc.;
7. purpose:
   • structural;
   • instrumental;
   • special.

Metals and alloys based on them have different physical and chemical characteristics.

The metal having the largest mass fraction is called the base.

What types of metal alloys are there?

Metals have been used by humans for many millennia. The defining eras of human development are named after the names of metals: the Bronze Age, the Iron Age, the Age of Cast Iron, etc. Not a single metal product around us consists of 100% iron, copper, gold or other metal. Each contains additives deliberately introduced by a person and harmful impurities introduced against the will of a person.

Absolutely pure metal can only be obtained in a space laboratory. All other metals in real life are alloys - solid compounds of two or more metals (and non-metals), purposefully obtained in the process of metallurgical production.

Classification of homogeneity of alloys

Traducción - aluminum alloy wire with Invar core - - en ingles

• 381 wire, copper-plated wire, copper-plated wire - [Ya.N. Luginsky, M.S. Fezi-Zhilinskaya, Yu.S. Kabirov. English-Russian dictionary of electrical engineering and power engineering, Moscow, 1999]

Topics

• electrical engineering, basic concepts

EN

Russian-English dictionary of normative and technical terminology > copper-coated wire

382 wire laid in the ground

wire laid in the ground —

[Ya.N.Luginsky, M.S.Fezi-Zhilinskaya, Yu.S.Kabirov. English-Russian dictionary of electrical engineering and power engineering, Moscow, 1999]

About metals and alloys

Hello, friends! Today I propose to consider some metals and their alloys . In this article we will try to cover all the possibilities and characteristics of metals and highlight their main advantages and qualities.

Iron

Iron is not considered an ancient human discovery. It began to be produced only in the 13th century BC. Gradually it became more and more important not only in production, but also in the construction of houses and other various buildings.

Without iron and products made from it, it is now difficult to imagine any economic and construction activity, although in fairness it should be noted that progress does not stand still, and iron is increasingly being replaced by various types of plastic.

But no matter how it is, there are cases when nothing can replace it. Although who knows, progress is such a thing

So, usually in metal work it is not pure iron that is used, but alloys - cast iron or steel.

Iron-carbon alloy

An alloy of iron with a carbon content exceeding 2% is cast iron.
Determination of steel grade by spark

Cast iron is almost impossible to process (let alone drill) and is highly brittle. The use of cast iron is very limited (it is more often used in casting; for example, everyone knows the good old cast-iron heating radiators).

An iron alloy containing less than 2% carbon is steel . It varies in the amount of carbon it contains.

Low-carbon grade steel (carbon does not exceed 0.3%) is more suitable for embossing or forging by hand, which is why it is also called ornamental. This grade of steel has excellent weldability and a high level of malleability. Only particularly low-carbon steel (less than 0.1% carbon) is difficult to harden.

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Medium-carbon grade steel (combines up to 0.85% carbon) is used for the production of most metal products. T.N. structural steel. Excellent hardening and forging properties, but very difficult to weld.

High -carbon steel (carbon content reaches up to 1.35%) is the hardest, and is used for the production of parts of mechanisms and tools subject to high wear. This steel is practically not forged and is difficult to weld.

Steel for various crafts is produced in the form of blanks in production. But it is more profitable to use its parts that have become unusable. To find out what grade of steel a part belongs to, there are many different methods of determination .

For example, if you file a steel part, heat it until red hot and cool it sharply in water. And if, when sawing again, you feel lightness, this is low-carbon steel. If there is difficulty, the percentage of carbon is higher. You can also determine the grade of steel by the sparks from the emery wheel. But a sufficient specialist can determine this.

There are special tables from which you can quite accurately find out the brand, and even the content of additives in steel.

Metal profiles, metal raw materials

Sheet metal is divided into thin sheet and thick sheet.

It is best to finish the edges of sheet metal with a planer made from a used hacksaw blade. Using an abrasive triangular stone, we grind out a corner cutout in the blade - the plane is ready.

Steel pipes are produced seamless (solid drawn) or welded (lap). The former are known as gas or steam pipes.

The most convenient way to cut a tin pipe is with a can opener. We make entry with a regular hacksaw.

Cast iron pipes are commonly used in water and sewerage systems.

The wire has three (main) or more types of sections - square, round or rectangular. Its surface can be copper-plated, tin-plated, galvanized or uninsulated. It can also be elastic or soft.

The rods are produced in round, hexagonal, square or flat sections.

The art of making light alloys yourself can be very rewarding. The most important thing is to prevent the metal from overheating.

Metals and alloys

The most common types of metals and alloys are: - copper , bronze, brass, aluminum, zinc, lead, tin, chromium, nickel, nickel silver and cupronickel.

 Light alloys

For crafts, pure copper (that is, red) or various light alloys are usually used.

Red copper is especially suitable for coining; it is very malleable and can be easily processed with various chemicals. substances to obtain different shades of color. In addition, it is perfectly ground and polished, and is characterized by high resistance to corrosion.

The disadvantage of red copper is its poor weldability (special electrodes for welding are required) and rapid oxidation in open air masses, which is why its original shine is lost.

Copper blanks (rods)

Bronze is obtained by fusing tin with copper. Workpieces made from it are harder and more durable than copper itself. Bronze is excellent for casting and forging. You are unlikely to find a ready-made bronze alloy on sale. Therefore, craftsmen often produce it themselves.

Bronze and brass sheets in rolls

Brass is an alloy of copper and zinc. In blacksmithing, it is used with individual alloying elements: aluminum, nickel, lead, etc.

Brass polishes and cuts better than red copper. It is beautifully plated with gold, silver, and nickel. But brass is inferior in ductility to copper.

Aluminum is a lightweight, soft metal with a light silver color. Its density is three times lower than that of steel. Aluminum, and in particular its alloys (high-strength structural, technical deformed, duralumin, etc.), which are widely used in light industry, are perfectly processed under normal conditions.

Zinc has a silvery-blue tint. When exposed to oxygen, it becomes covered with a matte film, which protects the metal from corrosion. Zinc is very useful for protecting various ferrous metals from corrosion, and this is where it is most often used (the so-called “galvanizing” - for example, the well-known drainpipes, galvanized metal of cars, etc.).

Zinc in ingots

Lead is soft, ductile and at the same time a heavy metal. Resistant to acids. Typically used for the production of low-melting solders and in the electrochemical industry.

Tin is a ductile and soft metal with a light silver color. Used to form anti-corrosion coatings. It is resistant to food acids and is therefore widely used in the manufacture of lids, cans, etc.

Chrome is a light blue metal. It has excellent anti-corrosion properties and high hardness. The efficiency of products made of steel or cast iron coated with chrome increases significantly.

Nickel is a light silvery metal. But unlike chrome, it has a delicate yellowish tint. More resistant to aggressive environments. Like chromium, it is widely used to protect decorative metal coatings - the so-called nickel plating.

Nickel silver and cupronickel are formed by alloying copper and nickel. The presence of copper in them is quite high - 82% and 66%, respectively. Because of this, they have good ductility.

When processed with lead acetic acid and sodium hyposulfate, different shades are produced. The surfaces of these metals are highly polished and have a number of other important features.

This concludes the article about metals and their alloys.

Source: http://odnastroyka.ru/metally-i-ix-splavy/

Teeth onlays: ceramic, removable, as they are called

NamePurposeMaterial of manufacture

Veneers	Improving the aesthetics of a smile, correcting minor dental defects.	Ceramics, composite materials, zirconium.
Lumineers	Improving the shade of teeth, correcting minor enamel defects.	Porcelain.
Ultraneers	Improving the aesthetics of a smile, correcting minor enamel defects.	Ultra-strong pressed ceramic.
Componeers	Elimination of minor aesthetic problems with teeth, including wedge-shaped defects.	Nanohybrid composite.
Mouthguards	Removable pads for whitening and teeth straightening.	Silicone, polyurethane.
Skyes	Decorative overlays in the form of rhinestones, glued to the tooth for beauty. Can mask minor defects.	Artificial diamonds, precious stones and metals.
Grillz	Removable decorative overlays for teeth in the form of complex jewelry.	Precious metals, alloys, precious stones. The base is made of silicone.

Ceramic onlays for teeth include porcelain and zirconium veneers, ultraneers and lumineers.

To completely install ceramic false teeth, it will take about a week, during which you will have to visit the dentist at least twice:

1. At the first appointment, the doctor assesses the condition of the teeth and oral cavity.
2. If the doctor detects an inflammatory process in the oral cavity or caries, treatment is carried out. If no contraindications to the installation of veneers, lumineers and ultraneers are found, the dentist and the patient select the optimal type of veneer for the teeth, select the material for its manufacture, and a color that matches the shade of the remaining teeth.
3. The tooth is processed, the top layer of enamel is polished (if necessary).
4. An impression of the jaw is created.
5. A temporary onlay is placed on the treated tooth, which protects its internal tissues from damage.
6. A permanent overlay is made within a few days.
7. During the second visit, the dentist tries on the finished onlay. If it is made correctly and does not cause discomfort, it is glued to dental cement.

We suggest you read: Why do people chatter their teeth in their sleep? Reasons

Composite veneers are installed in one appointment. They are made from the same light-curing materials that are used in dentistry for fillings. Preliminary grinding of the enamel is required only in certain cases. The installation process goes like this:

1. The dentist examines the oral cavity for contraindications.
2. If there are no contraindications, the top enamel layer is polished (if necessary).
3. Layers of composite material are applied to the treated tooth one after another.
4. The finished onlay is polished and the closure of the teeth is checked.

Composite overlays can be made in a laboratory by polymerizing the material in an oven. Such microprostheses are of higher quality.

Skyces are installed for beauty as permanent overlays, which are fixed with dental cement. No pre-treatment or grinding of tooth enamel is required. Sometimes it is necessary to make a depression in the enamel, which, after the end of the life of the skyce, is sealed with filling material. Skyces can be inserted into veneers to simultaneously eliminate defects and decorate the surface of the dentition.

Contraindications to the use of false teeth

Correcting and decorating teeth with onlays or attachments is not suitable for everyone. Dentists do not recommend resorting to such procedures when:

• inflammatory dental diseases accompanied by bleeding gums;
• diseases of the nervous system;
• allergic reaction to the materials used;
• the presence of bad habits - a tendency to grind teeth, chew hard objects and lack of proper hygiene skills.

Caring for dental veneers

If a person uses dental veneers, he should know how to care for them at home. Otherwise, the microprosthesis or decoration will quickly lose its aesthetic properties or break.

Rules for caring for dental veneers:

• After installing onlays in dentistry, you should immediately consult with your doctor about all the intricacies of oral care.
• After dental restoration, it is not advisable to eat very hard foods and viscous products, so as not to damage the lining.
• It is better not to consume foods and drinks that have aggressive and coloring properties (wine, coffee, pomegranates) or consume them in minimal quantities.
• You need to regularly brush your teeth and treat removable veneers with special solutions recommended by your dentist.
• Metal attachments and composite trims need to be polished periodically as their surfaces will scratch and dull over time.
• Several times a year you need to visit the dentist to monitor the condition of the oral cavity and the false teeth themselves, as well as professional cleaning of the products.

The use of false teeth helps a person correct many dental defects and brighten his smile. But the beauty of the dentition is achieved only with proper installation of structures and careful care for them. Therefore, you need to be careful when choosing a dental clinic and the materials used to make the onlays, and after installing them, you should monitor your hygiene and lifestyle.

Prices

On average, prices per tooth are as follows:

• 4,000–4,500 rubles for composite veneers;
• 14,000 or more rubles for porcelain veneers;
• 17,000 rubles and more for orthopedic zirconium onlays;
• 25,000 rubles and above for lumineers;
• 3,000 rubles per skyce.

The cost of grills is calculated individually depending on the materials, the presence of inlay, etc.

The result of installing onlays on teeth depends largely on the qualifications of the dentist. Our website contains a complete list of clinics that provide high-quality aesthetic dentistry services and successfully install therapeutic, orthopedic and decorative onlays.

snow-white lining smile

Source: https://denta-da.ru/belosnezhnaya-ulybka-nakladki-zuby/

Pipe D16T: standard and material features

By what standards are thin-walled and thick-walled pipes D16t produced? What material is it made from? How does this material differ from alternative solutions? Let's figure it out.

Meet the hero of our today's material.

Raw materials

First, let's separate the flies from the cutlets. D16t is a marking not of the pipe itself, but of the alloy from which it is made. Like all aluminum alloys, ours has a low density (about 2800 kg/m3).

The main disadvantage of aluminum is its low mechanical strength, which is largely offset by the addition of other elements of the periodic table.

Compound

According to GOST 4784-97, alloy D16 has the following composition:

Metal	Mass fraction, %
Fe	Up to 0.5
Si	Up to 0.5
Mn	0.3 — 0.9
Cr	Up to 0.1
Ti	Up to 0.15
Al	90.9 — 94.7
Cu	3.8 — 4.9
Mg	1.2 — 1.8
Zn	Up to 0.25
Third party impurities	No more than 0.15 (maximum 0.05 for each)

Please note: the amount of aluminum in the alloy is approximate. This metal is the base; Under certain conditions, the upper content limit indicated in the table may be exceeded.

So, the main components of the alloy are aluminum and copper.

What characteristics does such a composition provide?

• D16 is noticeably harder than pure aluminum. However, like all duralumin alloys.
• Strength is fully maintained in the range of up to 250 degrees Celsius. Actually, in the range of 120 - 250C this alloy has no equal among all types of duralumin.
• The upper limit of short-term heating is about 500C.

Post-processing

Perhaps the reader noticed that the name of the alloy - D16 - differs from the one in the title of the article D16t in the absence of a letter at the end.

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Blanks of alloys D16 and D16t.

It stands for post-processing method. The following options are possible:

Marking	Description
T	Hardened and naturally aged alloy
T1	Artificially aged
M	Annealed
A	Plated

Useful: in the price lists of manufacturers you can find markings like D16TA. This designates an alloy that has undergone hardening, natural aging and (after forming the part) plating.

Terminology

Some terms may need clarification.

• Annealing is heating to the recrystallization temperature (in our case, approximately 500C) followed by slow cooling. Without going into the physics of the process, we note that annealing gives metals increased ductility and toughness, and at the same time relieves internal stresses in metal structures.
• With rapid cooling from the recrystallization temperature to room temperature and below, the physical properties of the metal change in the other direction: on the contrary, it becomes extremely hard. The corresponding process is called hardening.
• Plating is the application of a layer of pure aluminum to the surface of the alloy. The fact is that it has greater corrosion resistance than many of its alloys; plating performs a protective function.

Broken cladding layer on a 5-ruble coin.

But the process of aging the alloy is so interesting that we will devote a separate section to getting to know it.

Aging

At the beginning of the 20th century (more precisely, a decade before the First World War, in 1903), the German materials scientist Alfred Wilm, an employee of the metallurgical factory Dürener Metallwerke AG, discovered an unexpected phenomenon while studying the properties of aluminum.

An alloy of 96% aluminum with 4% copper, after being quenched, like many other metals, quite predictably became harder and stronger. However, the process did not stop when the alloy reached room temperature: at 20C in the next 4-5 days, the metal continued to gain strength without losing its ductility.

The alloy was called duralumin (in honor of the German city of Duren, where its industrial production began in 1909), and its composition and heat treatment technology were quickly classified: at first it was widely used for the construction of frames for military airships.

The photo shows the German airship Graf Zeppelin. Duralumin was used to construct a rigid frame that made the aircraft resistant to gusts of wind.

However, the awl cannot be hidden in a bag: by 1920, duralumin had become the main material in aircraft construction around the world. During the experiments, another interesting property of the alloy was revealed: the process of gaining strength can be sharply accelerated by heating it after hardening to 188 - 193 degrees.

In this case, maximum strength was achieved in 11 - 13 hours, which, of course, from the point of view of manufacturability, looked much more advantageous.

How strong is the D16t alloy compared to pure aluminum? Let's compare their resistance to compressive loads: aluminum can withstand 7-8 kg/mm2, and duralumin 45.

Hardness, electrical and thermal conductivity of aluminum alloys.

There are a few more things to know about rafting.

Welding it is very problematic. As a rule, rivets are used to connect sheet parts with your own hands.

The rivets themselves are often made from the same D16t.

The priority area of ​​use of the alloy is aircraft construction; less often it is used for the needs of the automotive industry - mainly in the manufacture of bodies.

It cannot be called a cheap material. The price of the notorious pipes made from this type of duralumin is from 500 rubles per kilogram.

GOST 18482-79

Actually, let's get back to the pipes. They must be produced in accordance with GOST 18482-79 “Pipes pressed from aluminum and its alloys.”

Let's study the main provisions of the document:

• Pipes can be either round or shaped.

Several types of duralumin profiles.

• In terms of wall thickness, the standard provides for division only into thin-walled (wall up to 5 mm) and thick-walled (over 5 mm).
• The outer diameter for a round section, according to the assortment table contained in the standard, can vary from 18 to 300 millimeters . Maximum permissible deviations from the nominal size increase with increasing diameter and take values ​​from 0.5 to 2.8 mm up or down.
• The wall thickness can reach 93.116 millimeters with a 300 mm diameter.

Please note: the assortment table is not an immutable canon. Additional sizes may be introduced upon agreement with the supplier; In this case, tolerances are taken as for the smaller of the nearest diameters.

• The length of the products is from 1 to 6 meters: unmeasured, measured or multiple of measured . In the latter case, the instruction common to most similar standards applies: a 5-mm allowance is made for each cut. Interestingly, pipes made of softer alloys can be supplied in coils up to 15 kilometers long.

The hardness of the D16t alloy allows pipes to be supplied only in straight sections.

• Products with a wall thickness of over 10 mm and an outer diameter of 100 mm or more must not have burrs on their outer surface.

Conclusion

We will consider our acquaintance with the new material successful. We hope that it will be useful to the reader (see also the article “Pipe for underfloor heating: how to choose the optimal type and install it correctly”).

As always, the video in this article will offer additional information. Good luck!

Source: https://remstroymast.ru/tryba-d16t-standart-i-osobennosti-materiala.html

An alloy is a homogeneous composite material. Properties of alloys

Everyone has heard the word “alloy”, and some consider it synonymous with the term “metal”. But these concepts are different. Metals are a group of characteristic chemical elements, while an alloy is the product of their combination. Metals are practically never used in their pure form, and they are difficult to obtain in their pure form. Whereas alloys are ubiquitous.

What is an alloy

Let's look at this issue in more detail. So, an alloy is a combination of several metals or one and various non-metallic additives. Such connections are used everywhere. An alloy is a macroscopic homogeneous system obtained by melting. They have been known since ancient times, when humanity, using primitive technologies, learned to produce cast iron, bronze, and a little later - steel.

The production and use of these materials is due to the fact that it is possible to obtain an alloy with specified technological properties, while many characteristics (strength, hardness, corrosion resistance, and others) are higher than those of its individual components.

Main types

How are alloys classified? This is done according to the type of metal that is the basis of the connection, namely:

1. Black. The base is iron. Ferrous alloys include all types of steels and cast irons.
2. Colored. The base is one of the non-ferrous metals. The most common non-ferrous alloys are based on copper and aluminum.
3. Rare metal alloys. Based on vanadium, niobium, tantalum, tungsten. They are used mainly in electrical engineering.
4. Alloys of radioactive metals.

Other elements - metals and non-metals - are added to the main component of the alloy, which improve its technological properties. These additives are called alloying additives. Alloys also contain harmful impurities - if their permissible value is exceeded, many of the material’s characteristics are reduced. So now you know what an alloy is.

Alloys are also classified into double, triple and others - according to the number of components. According to the homogeneity of the structure - homogeneous and heterogeneous. According to their distinctive properties - low-melting and refractory, high-strength, heat-resistant, anti-friction, corrosion-resistant and materials with special properties.

Mechanical properties

The mechanical properties of alloys determine the performance of the material when exposed to external forces. In order to determine the characteristics of the connection, the sample is subjected to various tests (stretched, scratched, loaded, a metal ball or diamond cone is pressed into it, studied under a microscope) to determine strength, elasticity, and ductility.

The composition of the alloy determines its physical properties. These include specific gravity, electrical conductivity, melting point, specific heat capacity, coefficient of volumetric and linear expansion. Also physical are the magnetic properties of alloys. They are characterized by residual induction and magnetic permeability.

Chemical

What are the chemical properties of the alloy? These are characteristics that determine how a material reacts to the effects of various active, including aggressive, agents. The chemical effect of the environment can be seen visually: iron is “eaten up” by rust, a green coating of oxides appears on bronze, steel dissolves in sulfuric acid.

In metallurgy and heavy engineering, many methods are used to combat the aggressive influence of the external environment: new, more resistant materials based on copper, titanium and nickel are being developed, alloys are coated with protective layers - varnishes, paints, oxide films, and their structure is improved. As a result of negative environmental factors, industry annually suffers damage amounting to millions of tons of steel and cast iron.

Technological

Manufacturability – what is it? In industry, an alloy is not needed on its own; it is used to make a part. Consequently, the material will be heated, cut, deformed, subjected to heat treatment and other manipulations.

Manufacturability is the ability of an alloy to be subjected to various methods of hot and cold processing, for example, melting, easily spreading and filling a casting mold, deforming in hot or cold form (forging, hot and cold stamping), welding, and processing with metal-cutting tools.

Technological properties can be divided into:

1. Foundry. They are characterized by fluidity - the ability to fill the mold for casting, shrinkage (the percentage of volume loss after cooling, hardening) and segregation - a complex process in which a heterogeneous structure of the material is formed in different parts of the casting.
2. Ductility. This is the ability of an alloy to deform under impact load and take the desired shape without loss of integrity. Some metals have good malleability only when hot, others - both cold and hot. For example, steel is forged while hot. Aluminum alloys and brass take the desired shape well at room temperature. Bronze is difficult to deform by impact, and cast iron is not ductile and is destroyed under the influence of a hammer (with the exception of malleable cast iron).
3. Weldability. Low-carbon steel has good weldability; this characteristic is much worse for high-alloy steels and cast irons.

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What are the types and types of metals and their alloys?

In construction, industry and other areas of human life, various types of metals are often used. They differ from each other in the properties by which they are selected and used in a particular area. Materials are obtained in a variety of ways. Certain types of metals are combined together to create alloys that have unique physical and chemical properties.

Characteristics and Signs

Metals are a group of elements in the form of simple substances that have characteristic metallic properties. In nature they are present in the form of ores or compounds. Sciences such as chemistry, physics and metallurgy study the characteristics of these materials.

Metals have a combination of different properties. Mechanical factors determine their ability to resist deformation and destruction. Technological methods help determine the ductility of materials to various types of processing. Chemical properties show their interaction with different substances, and physical properties indicate their behavior in thermal, gravitational or electromagnetic fields.

Metals are classified according to the following properties:

• Hardness is the resistance of a material to penetration by another.
• Strength - preservation of shape, structure and size after exposure to dynamic, static and alternating loads.
• Elasticity is a change in shape without violating integrity during deformation and the possibility of returning to its original form.
• Plasticity is the retention of the resulting shape and integrity under the influence of forces.
• Wear resistance - maintaining external and internal integrity under the influence of prolonged friction.
• Viscosity - maintaining integrity under increasing physical stress.
• Fatigue is the number and period of cyclic impacts that a metal can withstand without changing its integrity.
• Heat resistance - resistance to high temperatures.

The primary characteristic of metals is the negative conductivity coefficient of electricity, which increases when the temperature drops, and is partially or completely lost when the temperature rises. Secondary characteristics of materials are metallic luster and high melting point. In addition, some types of metal compounds can be reducing agents in redox reactions.

Metallic properties are interrelated, since the components of the material affect all other parameters. Metals are divided into ferrous and non-ferrous, but they are classified according to many criteria.

Group with iron and its alloys

Ferrous metals are characterized by impressive density, high melting point and dark gray color. This group mainly includes iron and its alloys. To impart specific properties to the latter, alloying components are used.

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Subgroups of ferrous metals:

• Iron - iron, cobalt, manganese, nickel. They are usually taken as a base or as an additive to alloys.
• Refractory - tungsten, molybdenum, titanium, chromium. They melt at a temperature higher than the melting level of iron. Alloy steels are obtained from refractory varieties.
• Rare earths - lanthanum, neodymium, cerium. They have related chemical properties, but differ in physical parameters. Used as an additive to alloys.
• Uranium (actinides) - actinium, neptunium, plutonium, thorium, uranium. Widely used in nuclear energy.
• Alkaline earths - calcium, lithium, sodium. They are not used in free form.

Metals of the ferrous group are represented by iron alloys with different carbon content and the content of additional chemical elements: silicon, sulfur or phosphorus. Popular materials are steel and cast iron. Steel contains up to 2% carbon.

It is characterized by good ductility and high technological performance. In cast iron, the carbon content can reach 5%.

The properties of the alloy may differ with different chemical elements: with the content of sulfur and phosphorus, brittleness increases, and with chromium and nickel, cast iron becomes resistant to high temperatures and corrosion.

Colored varieties

Non-ferrous metals are more in demand than ferrous metals, since most of them are raw materials for the production of rolled metal. This group of materials has a wide range of applications: they are used in metallurgy, mechanical engineering, radio electronics, high technology and other fields.

Classification by physical parameters:

• Heavy - cadmium, nickel, tin, mercury, lead, zinc. Under natural conditions, they are formed in strong compounds.
• Lightweight - aluminum, magnesium, strontium, titanium and others. Characterized by a low melting point.
• Noble ones - gold, platinum, rhodium, silver. They are characterized by increased resistance to corrosion.

Non-ferrous metals are characterized by low density, good ductility, low melting point and predominant colors (white, yellow, red). Various equipment is made from them. Since the strength of the materials is quite low, they are not used in their pure form. Light alloys for various purposes are produced from them.

Materials of this group are characterized by impressive atomic weight and density, exceeding that of iron.

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Copper, which acts as a conductor of electric current, is in great demand.

It is characterized by a pinkish-red hue, low resistivity, good thermal conductivity, low density, excellent ductility and corrosion resistance. In the technical field, copper alloys are used: bronze (with the addition of aluminum, nickel or tin) and brass (with zinc).

Bronze is used in the production of membranes, round and flat springs, worm gears and various fittings. Tapes, sheets, wire, pipes, bushings, and bearings are made from brass.

The group of heavy metals is one of the main causes of environmental pollution. Toxic substances enter the oceans through wastewater from industrial plants. Some varieties of the heavy group can accumulate in living organisms.

Mercury is a highly toxic metal for humans. When coal is burned at power plants, its compounds pass into the atmosphere, and then are converted into sediment and end up in water bodies. Inhabitants of freshwater and marine systems accumulate large amounts of a dangerous substance, which leads to poisoning or death of people.

Cadmium is considered a trace element and a fairly rare element that can enter the ocean through wastewater from metallurgical plants. This substance is present in small quantities in the human body, but at high levels it destroys bone tissue and leads to anemia.

Lead is present in a dispersed state almost everywhere. When there is an excess of metal in the human body, health problems are observed.

Soft types

Silver-white aluminum is characterized by lightness, high corrosion resistance, good electrical conductivity and ductility. The characteristics of the material have made it useful in aircraft construction, the electrical industry and food production. Aluminum alloys are used in mechanical engineering.

Magnesium has low corrosion resistance, but the lightweight material is indispensable in the technical field. Alloys with this metal use aluminum, manganese and zinc, which are easy to cut and have high strength. Magnesium alloys are used in the production of cases for cameras, engines and other devices.

Titanium is used in mechanical engineering, the rocket industry and the chemical industry. Alloys containing this substance are characterized by low density, excellent mechanical properties, corrosion resistance and flexibility in pressure treatment.

Noble materials

Some types of metals are rarely found in nature and require labor-intensive extraction methods. The noble group metals are:

• Gold.
• Silver.
• Platinum.
• Rhodium.

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People learned about gold back in the Stone Age. The most expensive metal in the world can be found in nature in the form of nuggets, which contain a small amount of impurities. It is also found in alloys with silver.

Gold has thermal conductivity and very low resistance. Due to its good malleability, the material is used in the manufacture of jewelry.

Silver comes second in value after gold. In nature, it is usually found as silver ore. Silver is characterized by softness, ductility, thermal and electrical conductivity.

Platinum, discovered in the mid-20th century, is a rare material that can only be found in deposits of various alloys. It is quite difficult to obtain. The value of the metal lies in the fact that it is not affected by acids. When heated, platinum does not change color and does not oxidize.

Rhodium is also a noble metal. It has a silver color with a blue tint. Rhodium is resistant to chemical influences and temperature changes, but the fragile metal deteriorates under mechanical stress.

Hardness classification

Metals are also divided into hard and soft.

The hardest pure material in the world is chromium . It belongs to the refractory varieties and lends itself well to mechanical processing. Another solid element is tungsten.

It is characterized by high melting point, heat resistance and flexibility. Various parts are forged from it and small elements necessary for lighting fixtures are made. Tungsten is often present in heavy alloys.

Hard metals are not only difficult to mine, but also difficult to find on the planet. They are mainly found in meteorites that fell to Earth.

The softest metals include potassium, sodium, rubidium and cesium. Also in this group are gold, silver, copper and aluminum. Gold is present in marine complexes, granite fragments and the human body. External factors can destroy valuable metal.

Soft silver is used in the manufacture of dishes and jewelry. Sodium is widely used in almost every industrial sector.

Mercury, the softest metal in the world, is used in the agricultural and chemical industries, as well as electrical engineering.

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Refractory metals and their alloys

According to Wikipedia, refractory metals include metals that have a melting point of 2200 °C. Niobium, rhenium, molybdenum, tantalum and tungsten fall under this statement.

Name	Melting temperature
Niobium	2477°C
Molybdenum	2623 °C
Tantalum	3017 °C
Tungsten	3422 °C
Rhenium	3186 °C

Refractory metals are widely used in many industries and in everyday life. They are used in the manufacture of incandescent light bulbs, mobile phones, computers or, for example, nuclear reactors.

In a broader concept and practical application, refractory metals also include vanadium, hafnium, ruthenium, chromium, zirconium and osmium.

They are also used as alloying elements in alloys with metals from the first group to improve a set of operational or technological properties.

Pure metals themselves are of course used in production, for example, pure molybdenum and tungsten are used in the electronics industry, chemical engineering or in the production of heat treatment furnaces. But most of them are prone to brittle fracture at high temperatures, and they also have relatively low heat resistance. Much more interesting, from the point of view of increasing performance properties, is the use of alloys of these metals.

Refractory tungsten-based alloys

A representative of such alloys is the tungsten and niobium alloy BB2 with a heat resistance temperature of up to 1200°C. To increase corrosion resistance and refractoriness, tungsten alloys are alloyed with rhenium. And to increase wear resistance, thorium.

Molybdenum-based alloys

Molybdenum and its alloys are probably the most frequently used of all refractory materials. In industry, alloys alloyed with zirconium, boron, titanium, and niobium are often used: alloys TsM3, TsM6, TsM2A, VM3

Refractory niobium-based alloys

Niobium and its alloys, due to their high corrosion resistance, high heat resistance (up to 1300°C) and good performance under neutron irradiation, are widely used in the manufacture of nuclear industry products. As an example of niobium-based alloys, it is worth mentioning the alloys VN2, VN2A, VN3.

Methods for increasing the heat resistance and heat resistance of alloys

The heat resistance of refractory alloys, as mentioned above, is increased by alloying elements with a higher melting point, which form substitutional solid solutions in the alloy. Greater efficiency in increasing heat resistance and, in some cases, wear resistance can be achieved by dispersion hardening of the alloy with the formation of carbides (ZrC, NiC), nitrides (TiN) and oxides (ZrO2).

All refractory metals have low heat resistance, so intermetallic and ceramic coatings are used to protect them at temperatures above 400°C. For molybdenum and tungsten, silicon-based coatings (MoSi2, WSi2) are used. [1]

Literature:

1. Yu.M. Lakhtin, V.P. Leontiev., Materials Science, 1990

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Alloys - Chemistry

Metals have been used by humans for many millennia. The defining eras of human development are named after the names of metals: the Bronze Age, the Iron Age, the Age of Cast Iron, etc.

Not a single metal product around us consists of 100% iron, copper, gold or other metal.

Each contains additives deliberately introduced by a person and harmful impurities introduced against the will of a person.

Absolutely pure metal can only be obtained in a space laboratory. All other metals in real life are alloys - solid compounds of two or more metals (and non-metals), purposefully obtained in the process of metallurgical production.

Classification of homogeneity of alloys

Melts

Melt metal

Melt is a liquid state of a substance whose temperature is in the range between the boiling point and the melting point.

In fact, melts mainly include substances in a liquid state, which, however, under normal conditions predominantly exist in a solid state of aggregation. And although water, gases or alcohol in a liquid state are described within the framework of the melt model, they are often not classified as such.

Characteristics

Melts are characterized by so-called short-range order. This means that there is order in the arrangement of atoms (or molecules) relative to each other. In contrast to long-range and intermediate order, this ordering is observed only at distances on the scale of distances between atoms (or molecules).

The figure on the left (a) shows a lattice of quartz molecules - long-range order, and on the right (b) the arrangement of quartz glass molecules - short-range order

Application of melts

Melts are most widely used in metallurgy. Thus, with their help, alloys such as steel, brass and bronze are obtained. Thanks to the alloy of iron and carbon, cast iron is then obtained. A process such as electrolysis of melts makes it possible to obtain mass products such as sodium, potassium and aluminum.

The furniture industry also widely uses hot melt adhesive - a substance that, when heated, becomes viscous and fluid, and when cooled, hardens quite quickly. Due to these properties, approximately 95% of furniture manufacturers use hot melt adhesive.

Hot melt adhesive in granules

One of the effective ways to obtain ultrapure materials is the so-called metallurgical purification. During this process, recrystallization occurs and the substance passes through the melt phase. Also, various single crystals are often artificially obtained from melts by crystallizing them under certain conditions.

Sometimes solid amorphous bodies, which also have short-range order, are classified as melts having ultra-high viscosity.

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