Why alloys. Types of metals. Titanium alloys in orthopedic dentistry

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 a product of their combination. In its pure form, metals are practically not used, moreover, 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 the most ancient times, when mankind, with the help of 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 desired 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, which is the basis of the connection, namely:

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

Other elements - metals and non-metals - are added to the main component in the alloy, which improve its technological properties. These additives are called alloying. Also, harmful impurities are present in the alloys - if their permissible value is exceeded, many characteristics of the material 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 - into homogeneous and heterogeneous. By distinctive properties - into fusible 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 find out the characteristics of the connection, the sample is subjected to various tests (stretching, scratching, loading, pressing a metal ball or diamond cone into it, examining it under a microscope) to determine strength, elasticity, and plasticity.

Physical

The composition of an alloy determines its physical properties. These include specific gravity, electrical conductivity, melting point, specific heat capacity, coefficient of volumetric and linear expansion. Physical properties also include 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 the material reacts to the impact 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 covered with protective layers - varnishes, paints, oxide films, and their structure is improved. As a result of negative environmental factors, industry annually suffers damage in the amount of millions of tons of steel and cast iron.

Technological

Technology - what is it? An alloy in industry is needed not by itself, any part is made from it. Consequently, the material will be heated, cut, deformed, heat treated and other manipulations will be carried out. Manufacturability is the ability of an alloy to be subjected to various methods of hot and cold working, for example, to melt, to easily spread and fill a mold, to be deformed in hot or cold form (forging, hot and cold stamping), to be welded, processed with a metal-cutting tool.

Technological properties can be divided into:

Foundry. They are characterized by fluidity - the ability to fill the mold for casting, shrinkage (percentage of volume loss after cooling, solidification) and segregation - a complex process in which a heterogeneous material structure is formed in different parts of the casting.
the ability of an alloy to deform under shock loading 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 in hot form. Alloys of aluminum and brass take the desired shape well at room temperature. Bronze does not lend itself well to shock deformation, while cast irons are not ductile and are destroyed under the influence of a hammer (with the exception of
Weldability. Good weldability is much worse for cast irons.

When melted, metals usually mix to form alloys.

Even in ancient times, people noticed that in most cases alloys have other, often more useful properties for humans, than the pure metals that make them up. As you already know, bronze, for example, has a higher strength than its constituent copper and tin. Steel and cast iron are stronger than commercially pure iron. Therefore, pure metals are rarely used. Their alloys are used much more often. A little more than 80 metals are known, but tens of thousands of different alloys have been obtained from them.

In addition to greater strength, many alloys have greater corrosion resistance and hardness, better casting properties than pure metals. So, pure copper is very difficult to cast, it is difficult to obtain castings from it, and at the same time, tin bronze - an alloy of copper and tin - has excellent casting properties: artistic products are cast from it, requiring fine detailing. Cast iron - an alloy of iron and carbon - is also an excellent casting material. Pure aluminum is a very soft metal, relatively weak in tensile strength. But an alloy made of aluminum, magnesium, manganese, copper and nickel, called duralumin, is four times stronger than aluminium.

In addition to higher mechanical properties, alloys have properties that pure metals do not have. Examples are iron-based stainless steel - a material with high corrosion resistance even in aggressive environments and high heat resistance, magnetic materials, alloys with high electrical resistance, with a low coefficient of thermal expansion.

The components of alloys can be both non-metals and compounds.

According to the state of the components, alloys can be homogeneous, when, during fusion, a solution of one metal is formed in another, for example, alloys of copper and tin, gold and silver, and heterogeneous, for example cast iron, which is a mechanical mixture of iron and carbon.

Alloys are classified in different ways, depending on which feature is taken as the basis. Most often, alloys are divided by composition. For example, copper, aluminum, nickel, titanium and other alloys are isolated.

There are groups of alloys that have common names: bronze, brass, etc. Sometimes especially valuable components are noted in the name of the alloy: beryllium bronze, tungsten steel, etc.

In metallurgy, iron and all its alloys are classified into one group called ferrous metals, the rest of the metals and their alloys are technically called non-ferrous metals.

The vast majority of iron (or ferrous) alloys contain carbon. They are divided into cast iron and steel.

Cast iron- an iron-based alloy containing from 2 to 4.5% carbon, as well as manganese, silicon, phosphorus and sulfur. Cast iron is much harder than iron, it is usually very brittle, not forged, but breaks upon impact. This alloy is used for the manufacture of various massive parts by casting, the so-called foundry iron, and for processing into steel - pig iron.

Depending on the state of carbon in the alloy, gray and white cast iron are distinguished (Table 4).

Table 4
Types and properties of cast iron

	Compound	Properties	Application
Gray cast iron	Contains 1.7-4.3% C, 1.25-4.0% Si and up to 1.5% Mn. Due to the high content of silicon, the solubility of carbon decreases, so carbon is in a free state in the form of graphite	Relatively soft and machinable material. Free carbon makes cast iron soft	Production of cast parts (gears, wheels, pipes, etc.), artistic casting
white cast iron	Contains 1.7-4.3% C, more than 4% Mn, but very little silicon. Carbon is mainly contained in the form of cementite - iron carbide Fe 3 C	Hard and brittle material. These properties are imparted by cementite, which has a high hardness.	Recycling into steel

Steel- an iron-based alloy containing less than 2% carbon. According to the chemical composition, steels are divided into two main types: carbon and alloyed.

Carbon steel is an alloy of iron with carbon, but, unlike cast iron, the content of carbon in it, as well as manganese, silicon, phosphorus and sulfur, is much less. Depending on the amount of carbon, steels are divided into soft (carbon content does not exceed 0.3%), medium hardness (slightly more carbon than soft) and hard (carbon can be up to 2%). Machine parts, pipes, bolts, nails, paper clips, etc. are made of soft and medium hard steel, and various tools and utensils are made of hard steel.

Alloy steel is also an alloy of iron and carbon, only special alloying additives are introduced into it: chromium, nickel, tungsten, molybdenum, vanadium, etc.

Alloying additives give the alloy special qualities. So, chromium-nickel steels are very ductile, durable, heat-resistant, acid-resistant, resistant to corrosion (rust). They are used in construction (for example, the lining of the columns of the Mayakovskaya station of the Moscow metro is made of chromium-nickel steel (Fig. 32)), as well as for the manufacture of stainless household items (knives, forks, spoons), various medical and other instruments.

Rice. 32.
Mayakovskaya metro station with chromium-nickel steel column cladding

Chrome molybdenum and chrome vanadium steels are very hard, durable and heat resistant. They are used for the manufacture of pipelines, compressors, engines and many other machine parts of modern technology. Chrome-tungsten steels retain great hardness at very high temperatures. They serve as a structural material for high-speed cutting tools.

The properties of some alloy steels and their areas of application are presented in table 5.

Table 5
Properties of some alloy steels and their applications

alloying element	Special properties of steel	Products for which steel is used
	Hardness and corrosion resistance	Tools, cutters, chisels
	Viscosity, mechanical strength, corrosion resistance	Turbines of power plants and jet engines, measuring instruments, parts operating at high temperatures
Manganese	Hardness, mechanical strength, impact and friction resistance	Crusher parts, railway rails, excavator bucket teeth
	Heat resistance, mechanical strength at high temperatures, corrosion resistance	In aircraft, rocket and shipbuilding. Chemical equipment
Tungsten	Hardness and heat resistance, wear resistance	High-speed tools, saws, milling cutters, dies, electric lamp filaments
Molybdenum	Elasticity, heat resistance, corrosion resistance	Turbine blades for jet aircraft and automobiles, armor plates, laboratory glassware, electronic lamp parts
	Acid resistance	Transformers, acid-resistant devices and devices
	High strength, elasticity and impact resistance	Parts of automobiles, tractors and other machines subjected to impacts during operation

Steel is the basis of modern mechanical engineering, the defense industry, rocket science and other industries.

The works of D.K. Chernov and P.P. Anosov became of great importance in the development of modern metallurgy.

From non-ferrous alloys, we note bronze, brass, cupronickel, duralumin.

Bronze is an alloy based on copper with the addition (up to 20%) of tin. Bronze casts well, so it is used in mechanical engineering for the manufacture of bearings, piston rings, valves, fittings, etc. Bronze is also used for artistic casting (Fig. 33).

Brass is a copper alloy containing 10 to 50% zinc. They are used in motor building, for the manufacture of furniture fittings.

Cupronickel is an alloy containing about 80% copper and 20% nickel, similar in appearance to silver. It is used for the manufacture of relatively inexpensive cutlery and art products.

Duralumin (duralumin, duralumin) is an aluminum-based alloy containing copper, magnesium, manganese and nickel. It has good mechanical properties, it is used in aircraft and mechanical engineering (Fig. 34).

Rice. 34.
"Super Jett-100"

New words and concepts

Alloys and their classification.
Ferrous metals: cast irons and steels.
Non-ferrous metals: bronze, brass, cupronickel, duralumin.

Tasks for independent work

What period in human history is called the Bronze Age? Why?
Calculate the quantities of copper and nickel substances that need to be taken to produce 25 kg of cupronickel.
What unites two expressions: "alloying elements of steel" and "privileged position in society"?
Calculate the volume of hydrogen (n.a.) that is formed when 100 g of brass containing 13% zinc is dissolved in hydrochloric acid.

Metal in dentistry occupies a central place among the materials. Dental alloys are used to cast (or stamp) the majority of non-removable dentures, frames of removable dentures. Alloys in dentistry are used as auxiliary materials for soldering and stamping. They make dental instruments.

Article outline:

Classification of metals and alloys in dentistry
Structural metal alloys in orthopedic dentistry
Noble metal alloys in dentistry
Non-precious alloys in orthopedic dentistry
Auxiliary metal alloys in dentistry

Metals and alloys in dentistry Classification

All metals and alloys are divided into black and colored.

Black metals- this is iron and alloys based on it. Steel and cast iron. Cast iron contains more than 2.14% carbon. Not used in dentistry.

The surface of cast iron is matte and non-shiny. It does not lend itself well to polishing.

an iron-based alloy containing less than 2.14% carbon. In addition to iron and carbon, other metals are also present in steel. They give the alloy new properties (alloyed steel), including making it stainless.

Steel caps for stamping crowns

- an alloy of iron and carbon, with the addition of any other metals. They change the properties of the alloy (melting point, hardness, plasticity, malleability, etc.).

– steel resistant to corrosion. Chromium (21%), as well as other metals, is most often used as an anticarrosive agent.

are, respectively, all other metals.

Metals in orthopedic dentistry are divided into noble and non-noble.

noble metals(or precious metals) - metals resistant to corrosion and chemically inert. The main noble metals are gold, silver, and platinum group metals (platinum, palladium, iridium, osmium, etc.).

base metals- metals that are easily corroded, and are not found in nature in their pure form. They are always mined from ores.

Depending on the density

metals used in dentistry are light and heavy.

There is no single point of view on this issue. The most common criterion is that the density of the metal is greater than the density of iron (8 g / cm³) or the atomic weight is greater than 50 a.m.u. If at least one condition is met, the metal is heavy.

For ecology and medicine heavy metals are metals that are highly toxic and environmentally significant. Which creates even more confusion. For example, gold with a density of 19.32 g/cm³ and an atomic weight of 197 amu. not classified as a heavy metal, due to its inertness and excellent biocompatibility.

Dental metal alloys classification

By appointment, metal alloys in orthopedic dentistry are divided into:

A. Structural - dentures are made from them.

B. Alloys for filling - amalgams.

B. Alloys, for the manufacture of dental instruments.

G. Auxiliary. Metals used for other purposes (For example, fusible metals for stamping or solders).

According to the chemical composition, the alloys used in dentistry are:

Precious metal alloys

base metal alloys

Noble metals in dentistry and alloys

Noble metals are expensive in dentistry. But, despite this, they continue to be used because of their excellent biocompatibility. They are not subject to corrosion, do not react with saliva, do not cause allergies and intoxication.

Gold alloy can often be the only option for patients with polyetiological contact allergies.

Noble alloys are durable. Their only drawback (apart from the price) is their softness and susceptibility to abrasion.

Alloys of gold in dentistry.

900 gold alloy. (ZlSrM-900-40).

COMPOUND: 90% gold, 4% silver, 6% copper.

PROPERTIES: melting point 1063°C.

The alloy is plastic, easy to machine under pressure (stamping, rolling, forging).

Due to its low hardness, the alloy wears easily. Therefore, in the manufacture of stamped crowns from the inside, on the chewing surface or cutting edge, solder is poured.

Released: in the form of discs with a diameter of 18, 20, 23, 25mm and blocks of 5g.

Application: for stamped crowns and bridges made of

noble metal alloy in orthopedic dentistry

Alloy of gold of the 750th test (ZlSrPlM-750-80)

Consists from Gold - 75%, Silver and copper 8% each, and platinum - 9%

Platinum gives this alloy elasticity and reduces shrinkage during casting.

Apply for the manufacture of cast gold parts of clasp prostheses, clasps and inlays

Dental gold alloy 750th test (ZlSrKdM)

AT compound added cadmium - 5-12%.

Due to cadmium, the melting point of the alloy is reduced to 800 C. (The average melting point of gold alloys is 950-1050 C.), which makes it possible to use this alloy as a solder.

Silver-palladium alloys are distinguished by a higher melting point = 1100-1200 C. Their physical and mechanical properties are similar to gold alloys. But corrosion resistance is lower. (Silver darkens on contact with sulfur compounds) Alloys are ductile and malleable. They are soldered with gold solder (ZlSrKdM).

Alloy Pd-250

COMPOUND: 75.1% silver, 24.5% palladium, few alloying metals (zinc, copper, gold).

Apply for stamped crowns. They are produced respectively in the form of discs of various diameters (18, 20, 23, 25 mm) and a thickness of 0.3 mm.

Alloy Pd-190

Compound: 78% silver, 18.5% palladium, other metals.

Apply as an alloy for casting in dentistry.

Alloy Pd-150

Reduced the amount of palladium to 14.5%, increased silver.

Apply for tabs.

Non-precious metal alloys used in orthopedic dentistry

To reduce the cost of prostheses, alloys were developed based on cheaper metals to replace expensive gold.

In the USSR, cheap stainless steel was most widely used.

Today, the bulk of the market is occupied by cobalt-chromium and nickel-chromium alloys.

Alloy Stainless Dental-Steel Dental

Steel is the most common alloy in the world. Its properties are well known. And due to alloying agents, it can be given any properties you like.

Dental steel is very cheap.

Among the disadvantages: steel is heavy (density is about 8 g/cm3) and reactive. May cause allergies, galvanoses.

Stainless steel in orthopedic dentistry - grades:

STEEL GRADE 1 X 18 H 9T (EYA-1)

Dental alloy for crowns COMPOUND:

1.1% carbon; 9% nickel; 18% chromium; 2% manganese, 0.35% titanium, 1.0% silicon, the rest is iron.

Apply for fixed prostheses: individual crowns, cast teeth, facets.

STEEL GRADE 20X18H9T

COMPOUND: 0.20% carbon, 9% nickel, 18% chromium, 2.0% manganese, 1.0% titanium, 1.0% silicon, the rest is iron.

From this type of steel in the factory are made:

standard sleeves, going to the production of stamped crowns;

clasp blanks(for CHSP)

elastic metal matrices for fillings, as well as separation strips

STEEL for dentistry STAMPS 25Х18Н102С

COMPOUND: 0.25% carbon, 10.0% nickel, 18.0% chromium, 2.0% manganese, 1.8% silicon, the rest is iron.

APPLICATION: in the factory produce:

teeth(lateral upper and lower) for stamped-soldered bridges;

orthodontic wire diameter from 0.6 to 2.0 mm (step 0.2 mm)
.

As a solder for non-precious alloys, silver solder PSR-37 or Tsetrina solder is used.

Contains silver-37%, copper - 50%, manganese - 8-9%, zinc - 5-6%

Melting point - 725-810 C

Cobalt chromium alloy in dentistry

(cobalt-chromium alloy, cobalt-chromium alloy)

COMPOUND:

cobalt 66-67%, base alloy, hard, strong and light metal.
chromium 26-30%, introduced mainly (as in steel) to increase corrosion resistance.
nickel 3-5%, increases the plasticity, ductility, viscosity of the alloy, improves the technological properties of the alloy.
molybdenum 4-5.5%, increases the strength of the alloy.
manganese 0.5%, increasing strength, casting quality, lowering the melting point, helping to remove toxic sulfur compounds from the alloy.
carbon 0.2%, lowers the melting point and improves the fluidity of the alloy.
silicon 0.5%, improves the quality of castings, increases the fluidity of the alloy.
iron 0.5%, increases fluidity, improves casting quality.

PROPERTIES of CCS-alloy dental:

It is distinguished by good physical and mechanical properties, low density (and, accordingly, the weight of restorations) and excellent fluidity, which makes it possible to cast high-strength openwork products.

The melting point is 1458 C

The alloy is resistant to abrasion and retains a mirror finish for a long time.

Cobalt-chromium alloy in dentistry

It is used for cast crowns, bridges, solid cast clasp prostheses, frameworks of ceramic-metal prostheses, removable dentures with cast bases, splinting devices, cast clasps.

Metal-ceramic composition of metal in dentistry

Cellite-K - cobalt-chromium

an alloy that is part of a metal

cermets in dentistry.

Alloys in which the main element is Ni. The elements of this alloy, in addition to nickel, are Cr (at least 20%), Co and molybdenum (Mo) (4%).

Nickel alloy properties are close to those of cobalt alloy.

It is applied: for casting fixed prostheses and frameworks of removable prostheses.

Today, the use of nickel alloys is limited due to their high allergenicity.

Titanium alloys in orthopedic dentistry

In dentistry, both pure titanium (99.5%) and its alloys are used.

pure titanium

For casting and milling, alloys of titanium, aluminum and vanadium (90-6-4%, respectively) are used. And an alloy of titanium with aluminum and niobium (87-6-7%).

Titanium alloys are light and surprisingly strong. But refractory and difficult to process.

In orthodontics, alloys of titanium, vanadium and aluminum (75-15-10%) are used to make arcs.

Metals used in orthopedic dentistry

Nickel-titanium alloy - titanium nickelide – nickel 55%, titanium 45%.

The alloy has shape memory. Deformed cooled products from this alloy, when heated, acquire their original shape.

The alloy is used in orthodontics, where, under the action of body temperature, it takes
there is the right shape.

It is also used to make endodontic instruments with shape memory.

Auxiliary alloys used in orthopedic dentistry

Bronze- an alloy of copper and tin. Aluminum bronze is used in dentistry (aluminum instead of tin). Ligatures are made from it for splinting fractures of the jaws.

Brass- an alloy of copper and zinc - pins for collapsible models are made from it.

Magnaliy- an alloy of aluminum and magnesium - aircraft parts are made from it (the alloy is very light and durable). In dentistry, articulators and some cuvettes are made from it.

Amalgams- an alloy of metal with mercury. Used for filling.

The topic is too extensive, there will be a separate article about amalgam in dentistry.

Low-melting alloys in orthopedic dentistry

Low-melting alloys (Mellota, Wood, Rose) - contain Bismuth, Tin, Lead

- Their melting point is about 70 C.

They are used for dies when stamping crowns, counter dies, making collapsible models.

Low-melting metals in dentistry

Wood's alloy.

Melting point 68 C.

Composition: Bismuth - 50%, Lead - 25%, Tin - 12.5%, Cadmium - 12.5%.

It is toxic because it contains cadmium.

Mellot alloy.

Melting point 63 C

Composition: Bismuth - 50%, Lead - 20%, Tin - 30%.

Rose alloy for dentistry.

Melting point 94 C.

Composition: Bismuth - 50%, Lead and Tin 25% each.

Tool steel- contains carbon from 0.7% or more.

Differs in the high durability and hardness (after special heat treatment).

The addition of tungsten, molybdenum, vanadium and chromium to steel makes the steel capable of cutting well at high speeds. Such steel is used for burs and cutters.

Wolfram carbide- not an alloy. Chemical compound of tungsten with carbon (chemical formula WC). Comparable in hardness to diamond. Used for the production of armor-piercing tank shells. And also for carbide dental burs.

Zirconium dioxide- also not an alloy. Chemical compound of zirconium metal with oxygen. By chemical nature, it is close to ceramics, but harder and stronger. In dentistry, they are used for the manufacture of milled prostheses.

Alloys of metals used in dentistry (conclusion)

It is impossible to imagine modern dentistry without metals. They are at the core of everything. And there is no material that could replace metal.

The use of metals in dentistry

Metals in dentistry are used for:

Crowns and bridges
Frames of clasp prostheses
Metal bases chspp and pspp
dental implants
For tools and fixtures
As an auxiliary material for various technological processes
For filling

Video: Shape memory metal in medicine

Metal In Dentistry - Dental Alloys updated: February 4, 2017 by: Alexey Vasilevsky

The classification of metals should begin with the division of the entire class into ferrous and non-ferrous metals. Due to the unique properties of both types, it is possible to combine different chemical elements, which as a result form so-called alloys. In addition to pure iron and alloys, the group of metals includes metallides, as well as intermetallides (complex compounds of elements characterized by increased strength).

Ferrous and non-ferrous metals (alloys)

The group of ferrous metals includes two categories of compounds: steel (carbon, alloy), cast iron (ordinary, alloy, ferroalloy) and other iron-based alloys. The category of non-ferrous metals includes:

rare (tungsten, titanium, zirconium, molybdenum);
heavy (mercury, copper, lead, tin, zinc);
light (aluminum, magnesium) alloys.

The classification of non-ferrous metals can be continued with varieties of copper:

brass.

Some of these types are used more often in industry, while others are considered rare and less accessible. Ferrous alloys are very common in rolled metal, are in high demand and have good performance characteristics. Also popular is the manufacture of aluminum parts, which are subsequently actively exploited in a variety of industries: in mechanical engineering, medicine, food industry, chemical and aerospace sectors.

Properties of metals and alloys

It is possible to distinguish metals from alloys not only by external features, graininess, smoothness, but also by physical properties. These are thermal and electrical conductivity, high melting point and magnetization (inherent in iron alloys). At the same time, when heated, metals lose the property of electrical conductivity (not completely). At low temperatures, some types of metals, on the contrary, are considered superconductors of electricity. Metal surfaces also tend to oxidize to a greater or lesser extent. In other words, different types of metals and alloys are subject to rust (corrosion) and recovery in different ways.

Speaking directly about alloys, they are distinguished by the properties of hardness, ductility and strength. Physical characteristics separate alloys by color, electrical and thermal conductivity, magnetic attraction, and density. Aluminum, brass, copper, bronze and titanium can be considered the most common alloys in production for various combinations of properties. Various parts are made from these elements and ready-made products are poured.

The classification of metals can be more detailed if we consider them in terms of purposes and areas of use and the way they work (cast, powder, wrought). The most accurate division by type is the classification of metals according to state standards (GOST). Certain requirements for alloys and metals, their structural properties and scope become the main factors in choosing a metal for certain purposes.

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

Note: the main material in the manufacture of various products is metal. Depending on the chemical and physical qualities with which it is endowed, the metal is used in almost all types of products and works.

Iron

Iron is not considered an ancient human discovery. It began to be produced only in the 13th century BC. Gradually, it deserved more and more importance not only in production, but also in the construction of a house, and other various buildings. Without iron and iron products, 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 that's it. more often iron is replaced by various types of plastic. But whatever it was, there are cases when nothing can replace it. Although, who knows, progress is such a thing ...

iron alloy with less than 2% carbon is steel. It differs in the amount of carbon content it contains.

Low-carbon (carbon does not exceed 0.3%) is more suitable for chasing or forging by hand, so it is also called ornamental. This grade of steel has excellent weldability and corresponds to a high grade of ductility. Only very low carbon steels are difficult to harden.(less than 0.1% carbon).

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

AT high carbon steel(combination of carbon 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 factories. 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 various methods for determining.

For example, if you file a steel part with a file, heat it to red and cool it sharply in water. And if, when repeated, lightness is felt - this is low-carbon steel. With difficulty, the percentage of carbon is higher. It is possible to determine the grade of steel and by sparks from an emery wheel. But this can already be determined by a sufficient specialist.

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

Profiles of metals, metal raw materials

Rolled metal, pipes, sheets, wire and rods of various sections are considered elementary profiles of metals.

Sheet metal divided into thin-sheet and thick-sheet.

The edges of sheet metal are best processed with a plow obtained from a used hacksaw blade. With an abrasive trihedral bar, we grind an angular cut in the canvas - the plow 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 the entry with an ordinary hacksaw.

Cast iron pipes commonly used in water and sewer systems.

Wire has three (basic) or more types of sections - square, round or rectangular. Its surface can be copper-plated, tin-plated, galvanized or bare. It may also be elastic or soft.

rods produced round, hexagonal, square or flat.

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

Metals and alloys

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

light alloys

For crafts, as a rule, pure copper (that is, red), or various light alloys, is used.

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

Minus the same red copper is its poor weldability (requires special electrodes for welding) and rapid oxidation in open air masses, which is why its original luster is lost.

Note: When copper comes into contact with air, it oxidizes to a dark red color. And under the influence of moisture it becomes covered with a characteristic green color - patina.

Copper blanks (rods)

Bronze obtained by fusing tin with copper. Billets made from it are harder and more durable than those made from copper itself. Bronze is excellent for casting and forging. Finished bronze alloy, you are unlikely to find on sale. Therefore, masters often produce it themselves.

Sheets of bronze and brass in rolls

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

Brass is better polished and cut than red copper. It is perfectly covered with gold, silver, nickel. But brass in plasticity is inferior to copper.

Note: The brand of brass qualifies for different percentages of red copper - L72 - 72%, L66 - 66%. For ornamental blanks, it is recommended to use alloys with the highest copper content.

Aluminum- light, soft metal of 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.

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 in this it is most often used (the so-called "galvanization" - for example, well-known drainpipes, galvanized metal of cars, etc.).

Zinc in pigs

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

Tin- plastic and soft metal of light silver color. Used to form anti-corrosion coatings. Resistant to food acids and therefore widely used in the manufacture of lids, cans, etc.

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

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

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

During the processing of acetic lead and sodium hyposulfate, they give different shades. The surfaces of these metals are perfectly polished and have a number of other important features.

This concludes the article about metals and their alloys.

In the future, I propose to consider also the properties of and . See you again.

With best wishes, Vadim!

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