alloys are used. Metals and alloys

Metal alloys are called substances complex in composition, formed as a result of the interaction of two or more metals or metals with some non-metals. Chemical elements or their stable compounds included in

alloy, commonly referred to as components. Alloys can consist of two, three or more components.

The component that dominates quantitatively in the alloy is called the main component. Components introduced into the alloy to give it the desired properties are called alloying. The set of alloy components is called a system.

Alloys are classified according to the number of components - into double (binary), triple, quarter and multicomponent; by the main element - iron, aluminum, magnesium, titanium, copper, etc.; by application - structural, instrumental, heat-resistant, anti-friction, spring, ball-bearing, etc.; in terms of density - heavy (based on tungsten, rhenium, lead, etc.), light (aluminum, magnesium, beryllium, etc.); by melting point - refractory (alloys based on niobium, molybdenum, tantalum, tungsten, etc.), fusible (solders, babbits, printing alloys, etc.); according to the technology of manufacturing semi-finished products and products - foundry, deformable, sintered, granulated, composite, etc.

The ability of different metals to form alloys is far from the same; the structure of alloys after their hardening can also be very diverse.

Metal alloys in the liquid state, as a rule, are homogeneous and represent one phase.

phase called a homogeneous part of an inhomogeneous system, separated from its other parts by interfaces. During the transition of alloys from a liquid to a solid state, several phases can form in them. After solidification, depending on the nature of the components, the alloys may consist of one, two or more solid phases. It is possible to form solid solutions, chemical compounds and mechanical mixtures consisting of two or more phases.

solid solutions called alloys (of two or more components), in which the atoms of the soluble component are located in the crystal lattice of the solvent component. When a solid solution is formed, the solvent is the metal whose crystal lattice is preserved as a base. If both metals have the same type of crystal lattices and, as a result, unlimited mutual solubility in the solid state (they form a continuous series of solid solutions), then the solvent is the one whose concentration in the alloy exceeds 50% (atomic).

The formation of a continuous series of solid solutions requires the same type of crystal lattices of the components and a small difference in the periods of the crystal lattices.

A substitutional solid solution is formed by replacing some of the solvent atoms in its crystal lattice with atoms of the dissolved component (Fig. 1.6, a). These solutions can be limited and unlimited.

In solid solutions, diffusion transitions of components from places with a higher concentration to places with a lower concentration can occur until the concentration becomes the same throughout the volume. However, diffusion in solid solutions proceeds much more slowly than in liquid ones, and its rate decreases with decreasing temperature.

There are three types of solid solutions: substitution, insertion, and subtraction. Let us consider only the first two types of solid solutions, since subtraction solid solutions are relatively rare.

Rice. 1.6. Scheme of formation of solid solutions: o - atom of the base metal (solvent); - dissolved metal atom

Typically, components whose atomic lattice periods differ by no more than 8% form an unlimited range of substitutional solid solutions; 8-15% - substitutional solid solutions with limited mutual solubility; more than 15% - do not form solid solutions.

Interstitial solid solutions are formed by placing the atoms of the dissolved component in the free gaps between the atoms of the crystal lattice of the solvent (Fig. 1.6, b).

Chemical compounds are formed at a strictly defined quantitative ratio of the alloy components and are characterized by a crystal lattice that differs from the lattices of the initial components. Chemical compounds, as a rule, have characteristic physical and mechanical properties: high hardness, increased brittleness, high electrical resistance.

Chemical compounds in alloys are formed between metals (intermetallic compounds), as well as between metals and non-metals. Some compounds of metals with non-metals (carbides, nitrides, oxides, phosphides, etc.) have received independent use in technology.

Mechanical mixtures are formed with the simultaneous precipitation of crystals of its constituent components from the liquid melt during its cooling (eutectic mixtures). In the crystals that are part of the mechanical mixture, the crystal lattice of the initial components of the alloy is preserved. Mechanical mixtures may consist of pure components, solid solutions, chemical compounds, etc.

The phase rule (Gibbs' law) establishes a quantitative relationship between the number of degrees of freedom, the number of phases, and the number of components. The number of degrees of freedom of a system is understood as the number of independent external (temperature, pressure) and internal (concentration) variables that can be arbitrarily changed without changing the number of phases in the system.

For metal alloys under constant pressure, the variables are temperature and concentration. In this case, the phase rule takes the following form:

where C is the number of degrees of freedom; TO- number of system components;

F - number of phases.

During the crystallization of a pure metal, the system consists of one component (K= 1), solid and liquid phases (Ф = 2). At a constant pressure, such a system is invariant (the number of degrees of freedom is equal to zero) and the temperature cannot be arbitrarily changed in it without changing the number of phases.

For pure molten metal (K = 1, f= 1, C= 1) the system is single-variant, i.e. when the temperature changes, the equilibrium of the system is not disturbed.

These provisions are not unconditional. For example, in the selenium-tellurium system (the difference in periods is 17%), an unlimited number of solid solutions are formed. There are other exceptions as well.

The content of the article

ALLOYS, materials having metallic properties and consisting of two or more chemical elements, of which at least one is a metal. Many metal alloys have one metal as a base with small additions of other elements. The most common way to obtain alloys is to solidify a homogeneous mixture of their molten components. There are other production methods, such as powder metallurgy. In principle, it is difficult to draw a clear boundary between metals and alloys, since even the purest metals contain "trace" impurities of other elements. However, metal alloys are usually understood as materials obtained purposefully by adding other components to the base metal.

Almost all metals of industrial importance are used in the form of alloys ( cm. tab. 12). Thus, for example, almost all of the smelted iron is used for the manufacture of ordinary and alloyed steels, as well as cast irons. The fact is that alloying with certain components can significantly improve the properties of many metals. If for pure aluminum the yield strength is only 35 MPa, then for aluminum containing 1.6% copper, 2.5% magnesium and 5.6% zinc, it can exceed 500 MPa. Similarly, electrical, magnetic and thermal properties can be improved. These improvements are determined by the structure of the alloy - the distribution and structure of its crystals and the type of bonds between atoms in crystals.

Many metals, say magnesium, are produced in high purity so that the composition of the alloys made from it can be precisely known. The number of metal alloys used today is very large and is constantly growing. They are usually divided into two broad categories: iron-based alloys and non-ferrous alloys. The most important alloys of industrial importance are listed below and their main areas of application are indicated.

Steel.

Alloys of iron with carbon containing up to 2% of it are called steels. The composition of alloy steels includes other elements - chromium, vanadium, nickel. Steels are produced much more than any other metals and alloys, and it would be difficult to enumerate all kinds of their possible applications. Mild steel (less than 0.25% carbon) is consumed in large quantities as a structural material, while steel with a higher carbon content (more than 0.55%) is used to make low-speed cutting tools such as razor blades and drills. Alloy steels are used in mechanical engineering of all kinds and in the production of high-speed tools.

Cast iron.

Cast iron is an alloy of iron with 2-4% carbon. Silicon is also an important component of cast iron. A wide variety of very useful products can be cast from cast iron, such as manhole covers, pipe fittings, engine blocks. In correctly made castings, good mechanical properties of the material are achieved.

Alloys based on copper.

Basically it is brass, i.e. copper alloys containing from 5 to 45% zinc. Brass with a content of 5 to 20% zinc is called red (tompac), and with a content of 20–36% Zn - yellow (alpha brass). Brass is used in the manufacture of various small parts where good machinability and formability are required. Alloys of copper with tin, silicon, aluminum or beryllium are called bronzes. For example, an alloy of copper and silicon is called silicon bronze. Phosphor bronze (copper with 5% tin and trace amounts of phosphorus) has high strength and is used to make springs and membranes.

lead alloys.

Common solder (tretnik) is an alloy of about one part lead to two parts tin. It is widely used for connecting (soldering) pipelines and electrical wires. Sheaths of telephone cables and battery plates are made from antimony-lead alloys. Alloys of lead with cadmium, tin and bismuth may have a melting point well below the boiling point of water (~ 70° C); they are used to make fusible valve plugs for sprinkler fire-fighting water supply systems. Pewter, from which cutlery (forks, knives, plates) was previously cast, contains 85–90% tin (the rest is lead). Lead-based bearing alloys, called babbits, typically contain tin, antimony, and arsenic.

light alloys.

Modern industry needs high strength light alloys with good high temperature mechanical properties. The main metals of light alloys are aluminum, magnesium, titanium and beryllium. However, alloys based on aluminum and magnesium cannot be used in high temperature and aggressive environments.

aluminum alloys.

These include cast alloys (Al-Si), die-casting alloys (Al-Mg) and high-strength self-hardening alloys (Al-Cu). Aluminum alloys are economical, readily available, strong at low temperatures and easy to process (they are easily forged, stamped, suitable for deep drawing, drawing, extruding, casting, well welded and machined on machine tools). Unfortunately, the mechanical properties of all aluminum alloys begin to noticeably deteriorate at temperatures above about 175°C. But due to the formation of a protective oxide film, they exhibit good corrosion resistance in most common corrosive environments. These alloys conduct electricity and heat well, are highly reflective, non-magnetic, harmless in contact with food (because corrosion products are colorless, tasteless and non-toxic), explosion-proof (because they do not produce sparks), and absorb shock loads well. Due to this combination of properties, aluminum alloys serve as good materials for light pistons, are used in car, automobile and aircraft construction, in the food industry, as architectural and finishing materials, in the production of lighting reflectors, technological and household cable ducts, when laying high-voltage power lines.

The impurity of iron, which is difficult to get rid of, increases the strength of aluminum at high temperatures, but reduces corrosion resistance and ductility at room temperature. Cobalt, chromium and manganese weaken the embrittlement effect of iron and increase corrosion resistance. When lithium is added to aluminum, the modulus of elasticity and strength increase, which makes such an alloy very attractive for the aerospace industry. Unfortunately, despite their excellent strength-to-weight ratio (specific strength), aluminum-lithium alloys have poor ductility.

magnesium alloys.

Magnesium alloys are light, have high specific strength, good casting properties and excellent machinability. Therefore, they are used for the manufacture of parts for rockets and aircraft engines, housings for automotive equipment, wheels, gas tanks, portable tables, etc. Some magnesium alloys, which have a high coefficient of viscous damping, are used in the manufacture of moving parts of machines and structural elements operating in conditions of unwanted vibrations.

Magnesium alloys are quite soft, resist wear poorly, and are not very ductile. They are easily formed at elevated temperatures, are suitable for arc, gas and resistance welding, and can also be connected by soldering (hard), bolts, rivets and adhesives. Such alloys are not particularly corrosion resistant to most acids, fresh and salt water, but are stable in air. They are usually protected from corrosion by surface coating - chrome etching, dichromate treatment, anodizing. Magnesium alloys can also be brightened or plated with copper, nickel and chromium by pre-plating with molten zinc dipping. Anodizing magnesium alloys increases their surface hardness and abrasion resistance. Magnesium is a chemically active metal, and therefore it is necessary to take measures to prevent the ignition of chips and welded parts made of magnesium alloys.

titanium alloys.

Titanium alloys are superior to both aluminum and magnesium in terms of tensile strength and modulus of elasticity. Their density is greater than all other light alloys, but in terms of specific strength they are second only to beryllium. With a sufficiently low content of carbon, oxygen and nitrogen, they are quite plastic. The electrical conductivity and thermal conductivity of titanium alloys are low, they are resistant to wear and abrasion, and their fatigue strength is much higher than that of magnesium alloys. The creep strength of some titanium alloys at moderate stresses (on the order of 90 MPa) remains satisfactory up to about 600°C, which is well above the temperature allowed for both aluminum and magnesium alloys. Titanium alloys are sufficiently resistant to the action of hydroxides, salt solutions, nitric and some other active acids, but not very resistant to the action of hydrohalic, sulfuric and orthophosphoric acids.

Titanium alloys forging up to temperatures around 1150 ° C. They allow arc welding in an inert gas atmosphere (argon or helium), spot and roller (seam) welding. They are not very amenable to cutting (seizing of the cutting tool). The melting of titanium alloys must be carried out in a vacuum or controlled atmosphere to avoid contamination with oxygen or nitrogen impurities that cause embrittlement. Titanium alloys are used in the aviation and space industries for the manufacture of parts operating at elevated temperatures (150–430 ° C), as well as in some special-purpose chemical apparatus. Titanium-vanadium alloys are used to make light armor for the cockpits of combat aircraft. Titanium-aluminum-vanadium alloy is the main titanium alloy for jet engines and airframes.

In table. 3 shows the characteristics of special alloys, and in table. 4 shows the main elements added to aluminum, magnesium and titanium, indicating the resulting properties.

beryllium alloys.

A ductile beryllium alloy can be obtained, for example, by interspersing brittle grains of beryllium into a soft, ductile matrix such as silver. It was possible to bring the alloy of this composition by cold rolling to a thickness of 17% of the original. Beryllium surpasses all known metals in specific strength. Combined with its low density, this makes beryllium suitable for missile guidance devices. The modulus of elasticity of beryllium is greater than that of steel, and beryllium bronzes are used for making springs and electrical contacts. Pure beryllium is used as a neutron moderator and reflector in nuclear reactors. Due to the formation of protective oxide layers, it is stable in air at high temperatures. The main difficulty associated with beryllium is its toxicity. It can cause serious respiratory problems and dermatitis. see also CORROSION OF METALS and articles on individual metals.

Table 1. Some important alloys (composition and mechanical properties)

Table 1. SOME IMPORTANT ALLOYS (composition and mechanical properties)
		Typical mechanical properties
Alloys	Composition (main elements,%)	State	Yield strength (deformation 0.2%), MPa	Tensile strength, MPa	Elongation (on the length 5 cm), %
Aluminum
3003	1.2 Mn, 98.8 Al	Annealed	40	110	30
		Cold rolled 1	186	200	4
2017	4.0 Cu, 0.5 Mn, 0.5 Mg, 95 Al	Annealed	69	179	22
		Heat treated 2	275	427	22
5052	2.5 Mg, 0.25 Cr, 97.25 Al	Annealed	90	193	25
		Cold rolled 1	255	290	7
6053	1.3 Mg, 0.7 Si, 0.25 Cr, 97.75 Al	Annealed	55	110	35
		Heat treated 3	220	255	15
Alcled 2024	Core: 2024 (4.5 Cu, 0.60 Mn, 1.5 Mg, 94.4 Al). Coating: 99.75Al	Annealed	76	179	20
		Heat treated 3	310	448	18
		Heat treated 4	365	462	11
7075	5.6 Zn, 2.1 Cu, 3.0 Mg, 0.3 Cr, 89.0 Al	Annealed	100	228	17
		Heat treated 3	517	572	11
13	12–13 Si, 87–88 Al	Die cast	145	296	2,5
43	5.3 Si, 94.7 Al	Cast in sand form	55	130	8
		Die cast	110	228	9
214	4 Mg, 96 Al	Cast in sand form	82	170	9
Copper
Red brass	85 Cu, 15 Zn	Annealed	100	310	43
		Cold rolled 1	450	550	4
Cartridge brass	69 Cu, 31 Zn	Annealed	100	317	58
		Cold rolled 1	450	586	10
Yellow brass (high)	65 Cu, 35 Zn	Annealed	100	310	60
		Cold rolled 1	480	620	5
Admiralty brass	70 Cu, 29 Zn, 1 Sn	Annealed	124	365	60
		Cold rolled 1	676	689	3
Shipbuilding brass	60 Cu, 39 Zn, 0.75 Sn, 0.25 Pb	Annealed	100	372	40
		Cold rolled 1	270	427	30
Muntz metal	60 Cu, 40 Zn	Annealed	100	393	48
		Cold rolled 1	410	552	9
aluminum bronze	92 Cu, 8 Al	Annealed	206	524	55
		Cold rolled 1	689	924	13
manganese bronze	68 Cu, 29 Zn, 1 Fe, 1 Mn, 1 Al	Annealed	172	414	45
		Cold rolled 1	344	586	20
Phosphor bronze	95 Cu, 5 Sn, traces of P	Annealed	124	310	50
		Cold rolled 1	517	620	4
silicon bronze	96 Cu, 3 Si, rest Mn, Sn, Ni or Zn	Annealed	150	379	35
		Cold rolled 1	620	758	5
beryllium bronze	97.6 Cu, 2.05 Be, 0.35 Ni or 0.25 Co	Annealed	210	483	42
		Cold rolled 5	1100	1310	2
Nickel silver	60 Cu, 20 Zn, 20 Ni	Annealed	138	310	35
		Cold rolled 1	517	620	3
Cupronickel	70 Cu, 30 Ni	Annealed	228	440	35
		cold rolled	503	552	5
Magnesium
AZ92 (daumetal C)	9 Al, 2 Zn, 0.1 Mn, 88.9 Mg	Cast in sand form 3	150	275	3
AZ90 (daumetal R)	9 Al, 0.6 Zn, 0.2 Mn, 90.2 Mg	Die cast	150	228	3
AZ 80X (daumetal 01)	8.5 Al, 0.5 Zn, 0.2 Mn, 90.8 Mg	extruded	228	338	11
Nickel
Monel metal	67 Ni, 30 Cu, 1.4 Fe, 1 Mn	Annealed	240	517	40
		Cold rolled 1	689	758	5
Inconel	77.1 Ni, 15 Cr, 7 Fe	Annealed	241	586	45
		Cold rolled 1	758	930	5
iron
wrought iron	2.5 slag, the rest in the main. Fe	hot rolled	206	330	30
Technically pure iron	99.9 Fe	Annealed	130	260	45
Carbon steel SAE 1020	0.2 C, 0.25 Si, 0.45 Mn, 99.1 Fe	Annealed	276	414	35
Cast carbon steel	0.3 C, 0.4 Si, 0.7 Mn, 98.6 Fe	cast 6	276	496	26
		Cast 7	414	620	25
Type 302 stainless steel	18Cr, 8Ni, 0.1C, 73.9Fe	Annealed	207	620	55
Type 420 stainless steel	13Cr, 0.35C, 86.65Fe	Annealed	414	676	28
		heat treated	1380	1724	8
Cast iron	3.4 C, 1.8 Si, 0.5 Mn, 94.3 Fe	cast	-	174	0,5
Nitensil	2.7 C, 1.8 Si, 0.8 Mn, 2.3 Ni, 0.3 Cr, 92.1 Fe	Cast 8	278	552	-
Niresist type 2	2.8 C, 1.8 Si, 1.3 Mn, 20 Ni, 2.5 Cr, 71.6 Fe	cast	-	207	2
Nihard	2.7 C, 0.6 Si, 0.5 Mn, 4.5 Ni, 1.5 Cr, 90.2 Fe	Cast in sand form	-	379	-
		Cast in a chill mold	-	517	-
1 Leave for max. hardness. 2 Heat treatment for solid solution. 3 Heat treatment for solid solution and aging. 4 Solution heat treatment, aging and work hardening. 5 Leave for max. hardness and aging. 6 Casting and annealing. 7 Casting, water quenching, tempering from 677°C. 8 Casting and heat treatment.

Table 2. Some important alloys (physical properties, characteristics and applications)

Table 2. SOME IMPORTANT ALLOYS (Physical properties, characteristics and applications)
	Physical Properties
Alloys	Density	Melting point (range), °С	Coeff. thermal expansion (0–100° С), 10 –6 /K	Thermal conductivity (0–100° С), 10 6 W/(mChK)	Specific electro- resistance (0°C), 10–9 OmChm	Tensile modulus, 10 3 MPa	Feature and application
Aluminum
3003	2,73	645–655	22,9	8,32 6,70	98,9 125	68,9	Plastic and lightweight material. Tanks, pipes, rivets, etc.
2017	2,79	535–640	23,2	7,41 5,23	111 169	71,7	Aircraft building and other branches of technology where high specific strength is required
5052	2,67	590–650	23,6	6,00	144	70,3	Good strength, lightweight, corrosion resistant material
6053	2,69	580–650	23,2	7,41 6,70	111 125	69,0	Same
2024	-	500–640	23,0	-	-	-	Stronger than 2017
7075	2,80	480–640	23,2	5,23	169	71,7	Surpasses 2024 in strength.
13	2,66	576–620	19,8	6,14	140	71,0	Good casting properties. Excellent material for difficult castings
43	2,66	576–630	22,0	6,32 6,32	136 122	71,0 71,0	Good casting properties, gas-tight material. General purpose casting alloy
214	2,63	580–640	23,8	5,98	144	71,0	Good mechanical properties. Excellent corrosion resistance. Kitchen and milk utensils
Copper
Red brass	8,75	1023	17,6	6,85	143	103	Corrosion resistant. Water pipes, fittings
Cartridge brass	8,50	938	20,0	5,17	204	97	Cartridge cases and other deep drawing products
Yellow brass (high)	8,47	932	18,9	5,17	204	97	Brass for general use. Good mechanical characteristics.
Admiralty brass	8,54	934	18,4	4,73	214	103	Corrosion resistant. Condenser tubes
Shipbuilding brass	8,42	885	20,1	5,00	214	103	Salt water resistant. Shipbuilding
Muntz metal	8,40	904	19,4	5,42	184	90	Good high temperature properties and corrosion resistance
aluminum bronze	7,78	1040	16,6	3,00	357	103	High strength alloy, corrosion resistant. Propellers, gear wheels
manganese bronze	8,36	896	20,1	4,36	214	103	Increased strength. Pipe Fittings
Phosphor bronze	8,86	1050	16,9	3,52	290	103	High fatigue strength. Springs, membranes
silicon bronze	8,54	1018	17,1	1,40	816	103	High strength and fatigue resistance, corrosion resistance
beryllium bronze	8,23	954	16,6	4,00	-	-	Exceptionally high fatigue strength. Springs, membranes
Nickel silver	8,75	1110	16,2	1,45	893	128	Corrosion resistant white metal. The main material for silver-plated tableware
Cupronickel	8,94	1227	15,3	1,25	1122	139	Corrosion resistance. Condenser pipes, salt water pipelines
Magnesium
AZ 92 (daumetal C)	1,82	599	25,2	2,89	490	44,8	Light alloy for sand casting and multiple molds
AZ 90 (daumetal R)	1,81	604	25,2	2,98	520	44,8	Light Alloy Die Casting
AZ 80X (daumetal 01)	1,80	610	25,2	3,30	444	44,8	Light alloy for extrusion
Nickel
Monel metal	8,84	1299–1349	14,0	1,12	1480	179	Corrosion resistant. Kitchen and hospital equipment
Inconel	8,51	1393–1427	11,5	0,64	3000	214	Thermal and corrosion resistant alloy
iron

ALLOYS
materials having metallic properties and consisting of two or more chemical elements, of which at least one is a metal. Many metal alloys have one metal as a base with small additions of other elements. The most common way to obtain alloys is to solidify a homogeneous mixture of their molten components. There are other methods of production - for example, powder metallurgy. In principle, it is difficult to draw a clear boundary between metals and alloys, since even the purest metals contain "trace" impurities of other elements. However, metal alloys are usually understood as materials obtained purposefully by adding other components to the base metal. Almost all metals of industrial importance are used in the form of alloys (see Tables 1, 2). Thus, for example, almost all of the smelted iron is used for the manufacture of ordinary and alloyed steels, as well as cast irons. The fact is that alloying with certain components can significantly improve the properties of many metals. If for pure aluminum the yield strength is only 35 MPa, then for aluminum containing 1.6% copper, 2.5% magnesium and 5.6% zinc, it can exceed 500 MPa. Similarly, electrical, magnetic and thermal properties can be improved. These improvements are determined by the structure of the alloy - the distribution and structure of its crystals and the type of bonds between atoms in the crystals.
see also
METAL SCIENCE PHYSICAL;
CHEMICAL ELEMENTS. Many metals, say magnesium, are produced in high purity so that the composition of the alloys made from it can be precisely known. The number of metal alloys used today is very large and is constantly growing. They are usually divided into two broad categories: iron-based alloys and non-ferrous alloys. The most important alloys of industrial importance are listed below and their main areas of application are indicated.
Steel. Alloys of iron with carbon containing up to 2% of it are called steels. Alloy steels also contain other elements - chromium, vanadium, nickel. Steels are produced much more than any other metals and alloys, and it would be difficult to enumerate all kinds of their possible applications. Mild steel (less than 0.25% carbon) is consumed in large quantities as a structural material, while steel with a higher carbon content (more than 0.55%) is used to make low-speed cutting tools such as razor blades and drills. Alloy steels are used in mechanical engineering of all kinds and in the production of high-speed tools.
see also METAL-CUTTING MACHINES.
Cast iron. Cast iron is an alloy of iron with 2-4% carbon. Silicon is also an important component of cast iron. A wide variety of very useful products can be cast from cast iron, such as manhole covers, pipe fittings, engine blocks. In correctly made castings, good mechanical properties of the material are achieved.
see also METALS BLACK.
Alloys based on copper. Basically it is brass, i.e. copper alloys containing from 5 to 45% zinc. Brass with a content of 5 to 20% zinc is called red (tompac), and with a content of 20-36% Zn - yellow (alpha brass). Brass is used in the manufacture of various small parts where good machinability and formability are required. Alloys of copper with tin, silicon, aluminum or beryllium are called bronzes. For example, an alloy of copper and silicon is called silicon bronze. Phosphor bronze (copper with 5% tin and trace amounts of phosphorus) has high strength and is used to make springs and membranes.
lead alloys. Common solder (tretnik) is an alloy of about one part lead to two parts tin. It is widely used for connecting (soldering) pipelines and electrical wires. Sheaths of telephone cables and battery plates are made from antimony-lead alloys. Alloys of lead with cadmium, tin and bismuth may have a melting point well below the boiling point of water (ALLOYS 70° C); they are used to make fusible valve plugs for sprinkler fire-fighting water supply systems. Pewter, from which cutlery (forks, knives, plates) was previously cast, contains 85-90% tin (the rest is lead). Lead-based bearing alloys, called babbits, typically contain tin, antimony, and arsenic.
light alloys. Modern industry needs high strength light alloys with good high temperature mechanical properties. The main metals of light alloys are aluminum, magnesium, titanium and beryllium. However, alloys based on aluminum and magnesium cannot be used in high temperature and aggressive environments.
aluminum alloys. These include cast alloys (Al - Si), die casting alloys (Al - Mg) and high strength self-hardening alloys (Al - Cu). Aluminum alloys are economical, readily available, strong at low temperatures and easy to process (they are easily forged, stamped, suitable for deep drawing, drawing, extruding, casting, well welded and machined on machine tools). Unfortunately, the mechanical properties of all aluminum alloys begin to noticeably deteriorate at temperatures above about 175°C. But due to the formation of a protective oxide film, they exhibit good corrosion resistance in most common corrosive environments. These alloys conduct electricity and heat well, are highly reflective, non-magnetic, harmless in contact with food (because corrosion products are colorless, tasteless and non-toxic), explosion-proof (because they do not produce sparks), and absorb shock loads well. Due to this combination of properties, aluminum alloys serve as good materials for light pistons, are used in car, automobile and aircraft construction, in the food industry, as architectural and finishing materials, in the production of lighting reflectors, technological and household cable ducts, when laying high-voltage power lines. The impurity of iron, which is difficult to get rid of, increases the strength of aluminum at high temperatures, but reduces corrosion resistance and ductility at room temperature. Cobalt, chromium and manganese weaken the embrittlement effect of iron and increase corrosion resistance. When lithium is added to aluminum, the modulus of elasticity and strength increase, which makes such an alloy very attractive for the aerospace industry. Unfortunately, despite their excellent strength-to-weight ratio (specific strength), aluminum-lithium alloys have poor ductility.
magnesium alloys. Magnesium alloys are light, have high specific strength, good casting properties and excellent machinability. Therefore, they are used for the manufacture of parts for rockets and aircraft engines, housings for automotive equipment, wheels, gas tanks, portable tables, etc. Some magnesium alloys, which have a high coefficient of viscous damping, are used in the manufacture of moving parts of machines and structural elements operating in conditions of unwanted vibrations. Magnesium alloys are quite soft, resist wear poorly, and are not very ductile. They are easily formed at elevated temperatures, are suitable for arc, gas and resistance welding, and can also be connected by soldering (hard), bolts, rivets and adhesives. Such alloys are not particularly corrosion resistant to most acids, fresh and salt water, but are stable in air. They are usually protected from corrosion by surface coating - chrome etching, dichromate treatment, anodizing. Magnesium alloys can also be brightened or plated with copper, nickel and chromium by pre-plating with molten zinc dipping. Anodizing magnesium alloys increases their surface hardness and abrasion resistance. Magnesium is a chemically active metal, and therefore it is necessary to take measures to prevent the ignition of chips and welded parts made of magnesium alloys.
see also WELDING.
titanium alloys. Titanium alloys are superior to both aluminum and magnesium in terms of tensile strength and modulus of elasticity. Their density is greater than all other light alloys, but in terms of specific strength they are second only to beryllium. With a sufficiently low content of carbon, oxygen and nitrogen, they are quite plastic. The electrical conductivity and thermal conductivity of titanium alloys are low, they are resistant to wear and abrasion, and their fatigue strength is much higher than that of magnesium alloys. The creep strength of some titanium alloys at moderate stresses (on the order of 90 MPa) remains satisfactory up to about 600°C, which is well above the temperature allowed for both aluminum and magnesium alloys. Titanium alloys are sufficiently resistant to the action of hydroxides, salt solutions, nitric and some other active acids, but not very resistant to the action of hydrohalic, sulfuric and orthophosphoric acids. Titanium alloys forging up to temperatures of about 1150 ° C. They allow electric arc welding in an inert gas atmosphere (argon or helium), spot and roller (seam) welding. They are not very amenable to cutting (seizing of the cutting tool). The melting of titanium alloys must be carried out in a vacuum or controlled atmosphere to avoid contamination with oxygen or nitrogen impurities that cause embrittlement. Titanium alloys are used in the aviation and space industries for the manufacture of parts operating at elevated temperatures (150-430 ° C), as well as in some special-purpose chemical apparatus. Titanium-vanadium alloys are used to make light armor for the cockpits of combat aircraft. Titanium-aluminum-vanadium alloy is the main titanium alloy for jet engines and airframes. In table. 3 shows the characteristics of special alloys, and in table. 4 shows the main elements added to aluminum, magnesium and titanium, indicating the resulting properties.
beryllium alloys. A ductile beryllium alloy can be obtained, for example, by interspersing brittle grains of beryllium into a soft, ductile matrix such as silver. It was possible to bring the alloy of this composition by cold rolling to a thickness of 17% of the original. Beryllium surpasses all known metals in specific strength. Combined with its low density, this makes beryllium suitable for missile guidance devices. The modulus of elasticity of beryllium is greater than that of steel, and beryllium bronzes are used for making springs and electrical contacts. Pure beryllium is used as a neutron moderator and reflector in nuclear reactors. Due to the formation of protective oxide layers, it is stable in air at high temperatures. The main difficulty associated with beryllium is its toxicity. It can cause serious respiratory problems and dermatitis.
see also CORROSION OF METALS and articles on individual metals.
LITERATURE
Korotich V.I., Bratchikov S.G. Metallurgy of ferrous metals. M., 1987
Phase diagrams in alloys. M., 1986
Yudkin V.S. Production and casting of non-ferrous alloys. M., 1967-1971
Wagner K. Thermodynamics of alloys. M., 1957

Collier Encyclopedia. - Open society. 2000 .

See what "ALLOYS" is in other dictionaries:

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In his daily life is surrounded by various metals. Most of the items we use contain these chemicals. This all happened because people found a variety of ways to obtain metals.

What are metals

Inorganic chemistry deals with these valuable substances for people. Obtaining metals allows a person to create more and more perfect technology that improves our lives. What are they? Before considering the general methods for obtaining metals, it is necessary to understand what they are. Metals are a group of chemical elements in the form of simple substances with characteristic properties:

Thermal and electrical conductivity;

High plasticity;

Glitter.

A person can easily distinguish them from other substances. A characteristic feature of all metals is the presence of a special brilliance. It is obtained by reflecting incident light rays onto a surface that does not transmit them. Shine is a common property of all metals, but it is most pronounced in silver.

To date, scientists have discovered 96 such chemical elements, although not all of them are recognized by official science. They are divided into groups depending on their characteristic properties. So the following metals are distinguished:

Alkaline - 6;

Alkaline earth - 6;

Transitional - 38;

Lungs - 11;

Semimetals - 7;

Lanthanides - 14;

Actinides - 14.

Obtaining metals

In order to make an alloy, it is necessary first of all to obtain metal from natural ore. Native elements are those substances that are found in nature in a free state. These include platinum, gold, tin, mercury. They are separated from impurities mechanically or with the help of chemical reagents.

Other metals are mined by processing their compounds. They are found in various fossils. Ores are minerals and rocks, which include metal compounds in the form of oxides, carbonates or sulfides. To obtain them, chemical processing is used.

Recovery of oxides with coal;

Obtaining tin from tin stone;

Burning sulfur compounds in special furnaces.

To facilitate the extraction of metals from ore rocks, various substances called fluxes are added to them. They help remove unwanted impurities such as clay, limestone, sand. As a result of this process, low-melting compounds called slags are obtained.

In the presence of a significant amount of impurities, the ore is enriched before smelting the metal by removing a large part of the unnecessary components. The most widely used methods for this treatment are flotation, magnetic and gravity methods.

alkali metals

Mass production of alkali metals is a more complex process. This is due to the fact that they are found in nature only in the form of chemical compounds. Since they are reducing agents, their production is accompanied by high energy costs. There are several ways to extract alkali metals:

Lithium can be obtained from its oxide in a vacuum or by electrolysis of its chloride melt, which is formed during the processing of spodumene.

Sodium is extracted by calcining soda with coal in tightly closed crucibles or by electrolysis of a chloride melt with the addition of calcium. The first method is the most laborious.

Potassium is obtained by electrolysis of a melt of its salts or by passing sodium vapor through its chloride. It is also formed by the interaction of molten potassium hydroxide and liquid sodium at a temperature of 440°C.

Cesium and rubidium are mined by reducing their chlorides with calcium at 700-800°C or zirconium at 650°C. Obtaining alkali metals in this way is extremely energy intensive and expensive.

Differences between metals and alloys

There is practically no fundamentally clear boundary between metals and their alloys, since even the purest, simplest substances have some proportion of impurities. So what is the difference between them? Almost all metals used in industry and in other sectors of the national economy are used in the form of alloys obtained purposefully by adding other components to the main chemical element.

Alloys

The technique requires a variety of metallic materials. At the same time, pure chemical elements are practically not used, since they do not have the properties necessary for people. For our needs, we have invented different ways to obtain alloys. This term refers to a macroscopically homogeneous material that consists of 2 or more chemical elements. In this case, metal components predominate in the alloy. This substance has its own structure. In alloys, the following components are distinguished:

A base consisting of one or more metals;

Small additions of modifying and alloying elements;

Unremoved impurities (technological, natural, random).

It is metal alloys that are the main structural material. There are more than 5000 of them in technology.

Despite such a variety of alloys, those based on iron and aluminum are of the greatest importance for people. They are the most common in everyday life. The types of alloys are different. Moreover, they are divided according to several criteria. So various methods of manufacturing alloys are used. According to this criterion, they are divided into:

Cast, which are obtained by crystallization of the melt of mixed components.

Powder, created by pressing a mixture of powders and subsequent sintering at high temperature. Moreover, often the components of such alloys are not only simple chemical elements, but also their various compounds, such as titanium or tungsten carbides in hard alloys. Their addition in certain quantities changes the materials.

Methods for obtaining alloys in the form of a finished product or blank are divided into:

Foundry (silumin, cast iron);

Deformable (steels);

Powder (titanium, tungsten).

Alloy types

Methods for obtaining metals are different, while the materials made thanks to them have different properties. In the solid state of aggregation, alloys are:

Homogeneous (homogeneous), consisting of crystals of the same type. They are often referred to as single phase.

Heterogeneous (heterogeneous), called multiphase. When they are obtained, a solid solution (matrix phase) is taken as the base of the alloy. The composition of heterogeneous substances of this type depends on the composition of its chemical elements. Such alloys may contain the following components: solid solutions of interstitial and substitution, chemical compounds (carbides, intermetallides, nitrides), crystallites of simple substances.

Alloy properties

Regardless of which methods of obtaining metals and alloys are used, their properties are completely determined by the crystal structure of the phases and the microstructure of these materials. Each of them are different. The macroscopic properties of alloys depend on their microstructure. In any case, they differ from the characteristics of their phases, which depend solely on the crystal structure of the material. The macroscopic homogeneity of heterogeneous (multiphase) alloys is obtained as a result of a uniform distribution of phases in the metal matrix.

The most important property of alloys is weldability. Otherwise, they are identical to metals. So, alloys have thermal and electrical conductivity, ductility and reflectivity (shine).

Varieties of alloys

Various methods of obtaining alloys have allowed man to invent a large number of metallic materials with different properties and characteristics. According to their purpose, they are divided into the following groups:

Structural (steel, duralumin, cast iron). This group also includes alloys with special properties. So they are distinguished by intrinsic safety or anti-friction properties. These include brass and bronze.

For pouring bearings (babbitt).

For electric heating and measuring equipment (nichrome, manganin).

For the production of cutting tools (will win).

In production, people also use other types of metallic materials, such as low-melting, heat-resistant, corrosion-resistant and amorphous alloys. Magnets and thermoelectrics (telurides and selenides of bismuth, lead, antimony, and others) are also widely used.

Iron alloys

Almost all the iron smelted on Earth is directed to the production of simple iron. It is also used in the production of pig iron. Iron alloys have gained their popularity due to the fact that they have properties that are beneficial to humans. They were obtained by adding various components to a simple chemical element. So, despite the fact that various iron alloys are made on the basis of one substance, steels and cast irons have different properties. As a result, they find a variety of applications. Most steels are harder than cast iron. Various methods for obtaining these metals make it possible to obtain different grades (brands) of these iron alloys.

Improvement of alloy properties

By fusing certain metals and other chemical elements, materials with improved characteristics can be obtained. For example, pure aluminum is 35 MPa. Upon receipt of an alloy of this metal with copper (1.6%), zinc (5.6%), magnesium (2.5%), this figure exceeds 500 MPa.

By combining various chemical substances in different proportions, metal materials with improved magnetic, thermal or electrical properties can be obtained. The main role in this process is played by the structure of the alloy, which is the distribution of its crystals and the type of bonds between atoms.

Steels and cast irons

These alloys are obtained by and carbon (2%). In the production of alloyed materials, nickel, chromium, and vanadium are added to them. All ordinary steels are divided into types:

Low-carbon (0.25% carbon) is used for the manufacture of various structures;

High-carbon (more than 0.55%) is intended for the production of cutting tools.

Various grades of alloyed steels are used in mechanical engineering and other products.

An alloy of iron with carbon, the percentage of which is 2-4%, is called cast iron. This material also contains silicon. Various products with good mechanical properties are cast from cast iron.

Non-ferrous metals

In addition to iron, other chemical elements are used to make various metallic materials. As a result of their combination, non-ferrous alloys are obtained. In people's lives, materials based on:

Copper, called brass. They contain 5-45% zinc. If its content is 5-20%, then brass is called red, and if 20-36% - yellow. There are alloys of copper with silicon, tin, beryllium, aluminum. They are called bronzes. There are several types of such alloys.

Lead, which is a common solder (tretnik). In this alloy, 2 parts of tin fall on 1 part of this chemical. In the production of bearings, babbitt is used, which is an alloy of lead, tin, arsenic and antimony.

Aluminum, titanium, magnesium and beryllium, which are light non-ferrous alloys with high strength and excellent mechanical properties.

How to get

The main methods for obtaining metals and alloys:

Foundry, in which the solidification of various molten components occurs. To obtain alloys, pyrometallurgical and electrometallurgical methods of obtaining metals are used. In the first variant, thermal energy obtained in the process of fuel combustion is used to heat the raw material. The pyrometallurgical method produces steel in open-hearth furnaces and cast iron in blast furnaces. With the electrometallurgical method, the raw materials are heated in induction or electric arc furnaces. At the same time, the raw material is disintegrated very quickly.

Powder, in which the powders of its components are used to make the alloy. Thanks to pressing, they are given a certain shape, and then sintered in special furnaces.

Any production, from large to garage, deals with metal alloys, and not with pure metals (pure metals are used only in the nuclear industry). After all, even widespread steel is an alloy that contains up to two percent carbon, but these nuances will be discussed in more detail below. This article will describe most of the alloys, their production, basic and useful properties, applications, and many other nuances.

This article is about metal alloys, and we will not go deep into the jungle of materials science and describe absolutely all alloys, and this is unrealistic within one article. After all, if you delve into this topic, and touch on at least the majority, then you can stretch the article into an immense canvas. The most popular alloys from the point of view of the automotive and motorcycle industry (according to the subject of the site) will be described here, although other aspects of the industry will be slightly affected.

But besides alloys, one should still write a few words about the metals themselves, or rather about their amazing property, thanks to which various alloys appeared. And the main property of metals is that they form alloys, both with other metals and with non-metals.

The very concept of an alloy is not at all an obligatory chemical compound, because the unique properties of a crystal lattice lie in the fact that some of the atoms of one metal are replaced by atoms of another metal, or two crystal lattices, as it were, are built into each other.

And at the same time, as it were, irregular alloys are obtained, but the most surprising thing is that these irregular alloys, in terms of their properties, are obtained much better than pure metals. Moreover, by experimenting and manipulating with additives, at the output, you can get materials (alloys) with the necessary and useful qualities.

It should be noted that according to the technology of application, all alloys are divided into two large groups. The first group is wrought alloys, from which many parts are made by machining: forging, stamping, cutting, etc. And the second group of alloys is foundry and parts are obtained from them by casting into molds.

The first group of alloys has such properties as good ductility in solid form, and high strength, but the casting qualities of the first group are not high. The second group, on the contrary, has excellent casting properties, they fill the mold well during casting, but when they harden, their strength leaves much to be desired.

What is strength? - this valuable property is evaluated by various parameters, of which there are more than ten, but the most valuable property is the tensile strength of the alloy. In scientific terms, this is the stress of the alloy (measured in N / m², well, or in kg / mm²) which corresponds to the greatest load preceding the beginning of the destruction of the test part, relative to the initial cross-sectional area of \u200b\u200bthe part.

And now, speaking in a simpler language: we take a specially made part (according to the test standard) from the alloy being tested and fixing it in a special machine, we stretch it, gradually increasing the load, until the part is destroyed (it breaks).

Well, the applied force (which is controlled by devices and which was applied to the part, at the very moment before it breaks) divided by the cross-sectional area of the part, and shows its tensile strength (and, of course, the tensile strength of the alloy from which the tested part is made).

The most common metals on our planet (and, of course, the alloys obtained on their basis) are iron, aluminum, magnesium, and, oddly enough for many, titanium. All these metals in their pure form are not usable in technology, but their alloys, on the contrary, are very common.

Iron and metal alloys based on it.

Metal iron is the "bread" of the entire world industry. After all, most of the alloys used in the world industry (more than ninety percent) use iron alloys. Moreover, a very important addition to iron is not at all the addition of a metal, but of a non-metal - carbon.

If no more than two percent of carbon is added to iron, then we get the most demanded alloy (alloy number one) - this is steel. Well, if the carbon content in an iron alloy is more than two percent (from two to five), then we get cast iron, which is also the most important material in world industry. Let us now dwell on iron alloys in more detail.

Steel.

An alloy of iron and carbon, which contains no more than two percent carbon. It also contains impurities of silicon, manganese, phosphorus, sulfur, etc. As mentioned above, it is the most important alloy for industry, as it has excellent malleability and fairly high strength.

No matter what part of a car, motorcycle, or equipment (in a factory or in an ordinary garage) we would not glance at, everywhere we will see the presence of steel parts. The same suspension elements of cars and motorcycles, car body parts, frames, steering wheels, suspension and hitch of most motorcycles, internal parts, or, yes, much more, ranging from the most complex parts of various equipment to ordinary bolts and nuts.

The tensile strength is from 30 to 115 kg / mm² - this is for carbon steel, well, the tensile strength for alloy steel reaches 165 kg / mm².

Alloy steel is obtained by adding, in addition to carbon, also various alloying elements that add various important and useful properties to steel.

For example, the addition of manganese increases the resistance of steel to impact loads and adds hardness.
The addition of nickel improves corrosion resistance and ductility, and adds strength.
Vanadium increases resistance to shock loads, abrasion (reduces the coefficient of friction) and also adds strength to steel.
Chromium in the composition of steel also increases corrosion resistance and strength.

Well, with the addition of chromium and molybdenum in certain proportions, the most durable and pliable chromium-molybdenum steel is obtained, which is used for the production of critical parts, for example, for the production of frames for sports cars and motorcycles.

Well, the top of the metallurgical evolution was the legendary strongest steel "chromansil" (chromium-silicon-manganese steel) with the highest tensile strength.

And although the latest technologies do not stand still, and now, in addition to chrome-molybdenum and aluminum frames, frames are already being made (more precisely glued together) from composite materials (the same carbon, kevlar, etc.), but still steel frames, in addition to their strength, are also noticeable cheaper and therefore still used today. Well, I think most of the internal parts of engines, gearboxes and equipment (machine tools) will be made of steel for a long time to come.

Above, not all components were listed, the addition of which can significantly improve the properties of steel and, with a skillful approach, will achieve the necessary and important qualities of steel parts operating in different conditions.

In addition to many advantages, the main of which are strength and malleability, steel also has disadvantages. The first of these is the rather high cost and limitations on the weldability of alloyed steels (they use a complex welding technology), since ordinary alloying elements “volatilize” and significantly reduce the strength of the weld.

Well, for most steels (except stainless steels), another significant disadvantage is low corrosion resistance, although again, with the right addition of the necessary elements, corrosion resistance can be significantly increased.

Steel of various grades is produced in the form of rolled products: strips, strips, sheets, rods (round and hexagonal), profile material, pipes, wire, etc.

By purpose, steel is divided into structural, tool and special:

Structural contains up to 0.7 percent carbon and parts of machines, equipment, various instruments and devices are made from it.
Tool steel contains 0.7 to 1.7 percent carbon and is typically used to make various tools.
Special steels are heat-resistant steels, stainless steels, non-magnetic steels and other steels with special properties.

By quality, ordinary quality steel, high-quality and high-quality steel are divided:

Carbon structural steel of ordinary quality contains from 0.08 to 0.63 percent carbon. The carbon content in each grade of this steel, as a rule, is not precisely maintained and the grade is determined by the mechanical properties of this steel.

Sheet and strip material is made from steel No. 1, as well as various gaskets, rivets, washers, tanks, etc. And from steel No. 2 they make handles, loops, hooks, bolts, nuts, etc. As a rule, building structures are made from steel No. 3 and No. 4, and keys, cam couplings, wedges, rails, springs are made from steel No. 7, which are then heat-treated.

Carbon Structural Quality Steel contains up to 0.2 percent carbon and parts are made from it, which are subject to increased requirements for their mechanical properties and for heat-treated parts. This steel has a grade from No. 8 up to steel No. 70. And the number shows approximately the average carbon content in hundredths of a percent.

This steel is quite ductile and viscous, and thanks to this it is excellently stamped and welded. And in the manufacture of parts working with shock loads, or subject to friction, such parts from this steel are cemented. And steel with a carbon content of more than 0.3 percent is not cemented.

Nuts, bolts, studs and washers (for critical structures) are made from steel grades St 30 or 35, and shafts, couplings, bushings and other similar parts are made from steel 45, which are subjected to heat treatment (quenching and tempering). Well, gears, sprockets (gear wheels), connecting rods, springs and other parts that are also subjected to heat treatment are made from strong and hard steel grades St 50, 55 and 60.

Carbon structural quality steel, with a high content of manganese, which increases hardness and strength, is produced in grades from 15G, 20G, 30G and up to 70G or grades with the number 2: 10G2, 30G2 and up to 50G2. Well, the figure in front of the letter G again shows the average percentage of carbon (in hundredths of a percent). The letter G means that manganese in this steel is about 1 percent, and if the letter G is followed by the number 2, then the manganese content in such steel is about 2 percent.

Cemented parts are made from 10G2, 15G and 20G steels, engine connecting rods and wagon axles are made from 45G2 steel, and engine valve springs are made from 65G steel.

From structural alloy steel they make machine parts that must have greater strength, acid resistance, hardness (even with strong heating) and other qualities that are achieved by adding alloying components.

The two-digit number at the beginning of the steel grade indicates the percentage of carbon in hundredths. And the letters below indicate the alloying additive: H - nickel, X-chromium, C - silicon, B - tungsten, K - cobalt, T - titanium, M - molybdenum, G - manganese, Yu - aluminum, D - copper ... ..

The addition of chromium contributes to an increase in the hardness and strength of the steel (as well as corrosion resistance), while maintaining sufficient toughness of the steel. Gears (gears), crankshafts, worms, and other details are made from chromium steels. If the steel contains up to 14 percent chromium, then it perfectly resists corrosion. Such steel is used to make control and measuring and medical instruments. Well, if the percentage of chromium is more than 17 percent, then such steel becomes acid-resistant and stainless.
The addition of nickel increases the strength of the steel and also increases the corrosion resistance, as well as making the steel more ductile (less brittle).
The addition of silicon increases the strength and elasticity of steel, and therefore it is added to spring steel. If the steel contains a significant content of silicon and chromium, then such steel is called silchromium and has high heat resistance. Engine valves are made from silchrome steel.
The addition of molybdenum and tungsten increases the hardness and strength of steel, and these qualities are preserved even at fairly high temperatures, and therefore cutting tools are made from such steel.

The numbers behind the letter show the percentage of the alloying component. If there are no numbers behind the letter, then the alloying component is contained in the steel only about 1 percent. If the letter A is at the end of the marking, then this steel is of high quality.

Structural steel is produced in the form of sheets, strips and tapes, pipes, of different thicknesses, as well as bars (round, square and hexagonal) in the form of various beams that have a different section (T-beam, I-beam, angle, channel, etc.).

Various locksmith tools are made from carbon tool steel: chisels, hammers, blades, files, center punches, barbs, drills, wrenches, socket heads and various other tools.

Cast iron.

As mentioned above, if the carbon content in a metal alloy (more precisely, iron) contains from two to five percent, then such a material is cast iron. In addition to carbon, impurities of phosphorus, silicon, sulfur, and other components are added to cast iron. Cast iron with special impurities (chromium, nickel, etc.) that give cast iron special properties is called alloyed. The melting point of cast iron is 1100 - 1200 degrees.

Foundry iron is gray, white, ductile and malleable.

Gray cast iron contains carbon in the form of lamellar graphite (and part of cementite) and has relatively low hardness and brittleness, and is easily machined. But due to the low cost and excellent casting properties, various columns, plates, machine beds, electric motor housings, pulleys, flywheels, gears, heating radiators, and many other details are cast from gray cast iron. Gray cast iron is designated by the letters SCH and two two-digit numbers. For example, gray cast iron grade SCh21-40 has a tensile strength of 210 MN / m² (or 21 kgf / mm²) and in bending the strength is 400 Mn / m² (or 40 kgf / mm²).
White cast iron - it contains all the carbon in the form of cementite and this gives white cast iron great hardness, but also brittleness and this cast iron is difficult to machine.
Ductile iron contains carbon in the form of inclusions of nodular free graphite (with the addition of cementite) and this gives ductile iron greater strength than the gray cast iron described above. The strength of this cast iron is increased by the addition of alloying components such as nickel, chromium, molybdenum, and titanium. But ductile iron is more difficult to machine than gray cast iron. Critical parts are cast from this cast iron: blocks, heads, sleeves, pistons and cylinders of engines, compressors, gears and other parts of machines and equipment. This cast iron is marked with two letters HF and two numbers. For example, the VCh40-10 brand indicates that it is high-strength cast iron, with a tensile strength of 400 Mn / m² (or 40 kgf / mm²) with a relative elongation of 10 percent.
Ductile iron is produced by long-term languishing of ingots (castings) of white cast iron at a high temperature, which contributes to the burning of part of the carbon and the transition of the rest to graphite. At the same time, malleable cast iron receives useful qualities: relatively high bending resistance, good machinability, and lower density. Ductile iron is used to make parts of mechanisms that operate under conditions of increased stress and shock loads, as well as those operating at high pressures of steam, water, and gases. They make crankcases for rear axles and gearboxes of cars, gear housings for industrial equipment, brake discs, calipers and valves, water supply valves, chucks and faceplates for lathes and other parts. Ductile iron is denoted by the letters КЧ and two numbers. For example, the letters and numbers of the grade KCh45-6 mean that such cast iron is malleable and has a tensile strength of 450 Mn / m² (or 45 kgf / mm²) with a relative elongation of 6 percent.

It is common in industry (especially in the machine tool industry) no less than steel, and its cheapness (after all, it is the cheapest of structural materials) is probably one of the main factors in its popularity.

In addition, cast iron, in addition to its disadvantages, has quite useful properties. Cast iron perfectly fills various forms, but one of its main disadvantages is its brittleness. But despite the low strength, cast iron has long been used in engine building. Not so long ago, engine blocks, crankcase parts, crankcases of various gearboxes, cylinder liners, engine block heads, and pistons were cast from cast iron.

By the way, I’ll break away from the topic: cast-iron pistons, unlike aluminum ones, have the same expansion coefficient as the cast-iron sleeve, and therefore the piston-cylinder gap can be made minimal, and this helps to increase power and other useful properties. Of course, aluminum pistons are noticeably lighter than cast iron ones and behave better at high speeds and in a nickel-plated aluminum block, but it is still preferable to make pistons of various compressors from cast iron.

Well, and one more thing, despite the fact that nickel-plated aluminum blocks are now being manufactured for modern machines, many factories still pour cast-iron blocks. After all, if you add a little graphite to cast iron, you can significantly reduce the friction coefficient of the piston on the sleeve.

But still, cast-iron engine blocks are gradually being replaced by light-alloy ones, especially motorcycle engine blocks. And all due to the fact that cast iron has another significant disadvantage - it is quite heavy. And therefore, blocks (and cylinders) of engines of sports cars and motorcycles have been cast from aluminum since the twenties of the last century (about aluminum below).

At first they made aluminum blocks and cylinders with a cast-iron sleeve, then they abandoned the cast-iron sleeve and now they began to cover the cylinder walls with various hard and wear-resistant galvanic coatings, first chrome, then nikasil, then more complex metal-ceramic compositions, the most advanced of which is keronite, about which I wrote more.

But still cast iron is still used (especially in the machine tool industry) and especially malleable cast iron. After all, malleable cast iron is more ductile than ordinary and stronger. The tensile strength of ductile iron is from 30 to 60 kg / mm², and this allows it to be used not only in machine tool building, but also to manufacture machine and motorcycle parts, because brake discs are still made of ductile iron.

Well, some brands of cast iron are still used for the manufacture of engine crankshafts (for example, in), as well as for the manufacture, do not forget that when graphite is added, cast iron rings have a low coefficient of friction, and this is important for any engine. Well, one more thing: many probably know that the cast-iron engine head (despite its greater weight) is less prone to deformation at than a lighter aluminum head.

And yet, for quite a long time, cast iron will be the number two material (after steel) in almost any heavy industry.

Non-ferrous metals and metal alloys.

Despite the fact that the topic of the article is metal alloys, one should definitely mention non-ferrous metals, on the basis of which most alloys are obtained. Non-ferrous metals include almost all metals except iron. And they are divided into:

light: rubidium, lithium, sodium, potassium, sodium, cerium, beryllium, calcium, magnesium, titanium and aluminum.
heavy: lead, zinc, copper, cobalt, nickel, manganese, tin, antimony, chromium, bismuth, arsenic and mercury.
noble: platinum, gold, silver, palladium, rhodium, iridium, octium, ruthenium.
rare: molybdenum, tungsten, vanadium, tantalum, tellurium, selenium, indium, cesium, germanium, zirconium, etc.

But if you start to describe everything, then, as mentioned at the beginning of the article, it will turn into an immense canvas. And below, only those metals and their alloys that are most common and used in the auto-moto industry will be described.

Aluminum.

As many people know, iron has been known to mankind for several thousand years, but aluminum has been used for only a couple of hundred years. And the most interesting thing is that aluminum was initially considered a jewelry material, and the technologies for its extraction and production were so expensive that it was considered almost more expensive than silver.

Many people know the story of how a certain ruler, having received an aluminum cup made and polished by him from a jeweler, was so struck by the beauty of this metal and its products that he began to worry about his silver reserves and that his silver would depreciate due to aluminum. From this, the poor jeweler was executed, and the goblet was securely hidden.

And probably this white metal and its alloys would have remained a jewelry material, if not for the development of aviation. Indeed, sooner or later, the first aircraft made of wood had to prove their fragility, which happened, and then the engineers seriously took up the improvement of aluminum production.

And it was worth trying, because this structural material is three times lighter than steel. The density of aluminum alloys ranges from 2.6 to 2.85 g/cm² (depending on composition). Of course, engineers initially encountered the fact that the mechanical properties of aluminum are not at all high, because the tensile strength even for cast aluminum alloys is only from 15 to 35 kg / mm², and for wrought alloys from 20 to 50 kg / mm² and only for the most expensive and multi-component alloys, the strength reaches 65 kg / mm².

And if we compare it with steel, then at first glance it will seem that there is no gain at all: aluminum is three times lighter than steel, but also three times weaker. But nobody canceled the laws of strength of materials and they became a salvation for engineers, because the rigidity of a structural part depends not only on the strength of the material from which it is made, but also on its geometric shape and dimensions.

And in the end it became clear that an aluminum part of the same weight as a steel one is much more rigid in torsion and bending. Well, if the stiffness indicators of the steel and aluminum parts are the same, then the aluminum part will still be lighter in weight, which is necessary for aviation and not only for it.

And around after the First World War, aluminum alloys began to conquer the world industry. Of course, at the beginning, aluminum poured into the aviation industry (hulls, wings of aircraft), later crankcases, pistons were cast from it, and not only for aircraft engines, but also for cars and motorcycles. And even later, they began to cast cylinder heads and the cylinders themselves, or engine blocks for almost all vehicles.

By the way, the matter was not limited to engine parts, and even at the end of the twenties of the last century, attempts were noticed to make frames of sports cars and motorcycles from aluminum alloys, as well as bodies, but nevertheless, such products were only put on stream for many mass-produced cars and motorcycles. towards the end of the 1980s.

Well, in modern technology, aluminum parts (except those listed above) can be listed almost endlessly - these are parts of both cars and motorcycles (scooters, bicycles), frames, pendulums, steering wheels, traverses, various brackets, up to the roof racks of the car or on the rear fender of a motorcycle. Yes, there is little else.

Well, further it is worth mentioning one feature of aluminum itself and aluminum metal alloys. Aluminum is a very active metal to the environment, but the most interesting thing is that the super activity itself helps it to survive (to protect itself from corrosion). After all, aluminum is such an active metal that it instantly reacts with oxygen in the air (and the moisture present in it).

And from this, the thinnest oxide film is instantly formed on the surface of the aluminum part, and it is this film that protects any aluminum part from corrosion. Although different alloys, depending on the components, have different corrosion resistance. For example, cast alloys have good protection, but on deformable alloys, the oxide film is very thin and weak, and its protective properties directly depend on alloying additions to the alloy.

For example, such an aluminum alloy as duralumin, widely known and used in aviation, has such a weak oxide film that it corrodes very quickly, becoming covered with a white coating, and if it is not covered with a protective coating, then corrosion will quickly “eat” it.

As a coating, it was previously covered (clad) with a thin film of pure aluminum, but now, with a wide development, it is covered with various coatings of various rather bright colors (gold, bright blue, red, etc.).

Well, it’s also worth writing a few words about aluminum itself - it is a low-density metal that lends itself well to forging, stamping, pressing, cutting, and besides, it has a fairly high electrical and thermal conductivity. And therefore it is quite widely used in electrical engineering (electrical industry), instrument making, mechanical engineering, aviation, both in pure form and in the form of alloys.

Having relatively sufficient strength and hardness, aluminum alloys with copper, manganese, silicon and magnesium are called duralumin, which, as mentioned above, is used in aircraft construction, mechanical engineering and other industries.

Along with duralumin, almost all aluminum-based alloys (like steel) are produced in the form of rolled products: strips, tapes, sheets, rods (round and hexagonal), profile material, pipes, wire ...

Magnesium.

Probably everyone who held a piece of this interesting and one of the lightest metals in their hands, it seems that it is not metal at all, but a piece of plastic, it is so light. It is one of the lightest metals used in engineering. And its alloys with zinc, aluminum, silicon and manganese are used in the manufacture of various parts of radio equipment, instruments, etc.

Previously, this metal was called the buzzword electron. The density of this metal is four and a half times less than that of iron and is only 1.74 g / cm³, and 1.5 times less than that of aluminum alloys. But the strength of magnesium is lower and the tensile strength for cast magnesium alloys is from 9 to 27 kg / mm², and for wrought alloys from 18 to 32 kg / mm².

It would seem that there is very little strength, but again, we do not forget that no one has repealed the laws of strength of materials, and it would seem that very little weight covers everything.

But in addition to low strength, magnesium has more significant disadvantages, the first of which is the high price. And parts of motorcycles or cars made of magnesium significantly raise their price. But this is not all the disadvantages: in the production of mania, it ignites very easily when it is cast (well, or when welding) and even when it is machined!

In addition, magnesium is very unstable to environmental influences (corrosion) and every part made of magnesium has to be protected from corrosion twice - first oxidized, and then coated (paint or galvanized). But in bad conditions (for example, in the aggressive environment of winter roads), a small scratch on the coating of a magnesium part is enough and it begins to instantly corrode and quickly collapse.

But still, too little weight overshadows all the disadvantages and magnesium alloys are used to manufacture expensive parts for cars and motorcycles (and not only). And they began to use it back in the twenties of the last century, and in the 80s its use almost doubled even on serial equipment. For example, some not very important parts - crankcase covers, crankcases themselves, head covers and other parts (by the way, the engine crankcase of even our cheapest Soviet car - Zaporozhets was cast from a magnesium alloy).

But still, magnesium alloys have been and are still used only for the manufacture of frames, chassis, wheels and other parts of sports equipment, more precisely, some expensive production cars and motorcycles, for example, elite sportbikes from the Italian company Agusta, the motorcycle model MV Agusta F4 750 Serie Oro , which cost twice as much as sportbikes of the same company, but with aluminum frames, and the difference in weight was only 10 kg.

But I think in the future, with the development of electroplating and the use of more resistant coatings, the use of magnesium will increase even more.

Titanium.

Well, this is quite an interesting material and the name itself speaks for itself. By the way, it appeared due to the titanic difficulties of extracting it from the earth's crust, especially at the initial stage of its extraction. At first glance, titanium looks like steel, until you pick it up and feel that it weighs significantly less.

As I mentioned just above, a rather complicated technology for extracting it from the earth's crust determined its high price and low prevalence. Most metals and alloys have been mined for several centuries, but metallic titanium was obtained only in 1910 of the last century. And by the 50s of the last century, just over two tons of titanium had been mined on our entire planet!

But after the 50s of the last century, with the development of space exploration (space technology and high-speed aviation), titanium turned out to be the best of the structural materials, due to its great strength and lightness (we will talk about the unique properties of titanium a little later), and its production began to develop rapidly.

Despite the fact that titanium is significantly lighter than steel (4.51 g / cm³), the strength of its alloys is almost the same as that of the best alloy steels (75 - 180 kg / cm²). In addition, unlike steel, titanium has excellent corrosion resistance, since its oxide film has a high strength. But that's not all: some titanium alloys have a fairly high heat resistance.

In addition, titanium alloys are normally welded in a neutral environment, are not poorly processed, and have good casting properties. In short, titanium has plenty of pluses, and if it were not for one significant minus - its high price, then everyone would probably forget about steel.

And precisely because of the high price, the use of titanium in the auto-moto industry is still limited. But on sports equipment, which has never been distinguished by a modest price, the use of titanium is increasing every year. After all, it's not a secret for anyone that from the space industry, almost all technical achievements smoothly turn into auto-moto sports.

And over time, parts of the undercarriage of sports cars and motorcycles began to be made from titanium and its alloys, but still, parts of forced revolving motors are most often made from it: valves and their springs, connecting rods and other parts for which the main requirement is high strength and ease. And on the most expensive sports cars, even fasteners (bolts, studs and nuts) are made of titanium.

One more thing should be said: just as there was a smooth “flow” of titanium parts from the space industry to sports, I think subsequently there will also be a gradual flow of the use of titanium for production cars and motorcycles, however, let's wait and see...

Copper.

This metal has a relatively high density, has a characteristic reddish color and excellent ductility. Also, copper has a fairly high coefficient of friction, and excellent electrical and thermal conductivity.

Due to this property, electrical wiring, contacts, terminals, parts of radio equipment and devices (up to soldering irons) are made from copper and its alloys, and are used for food industry equipment. Well, due to the high coefficient of friction, copper is used even for the manufacture of various friction linings of friction clutches and copper additives can even be found in clutch discs of cars and motorcycles.

But in most cases, pure copper is now quite rarely used in order to save money, mainly as part of alloys based on it (brass and bronze - about them later) or as coatings (by the way, now copper coating has even become more popular than chromium, for example, on custom motorcycles in the style old school customization - old school).

But still, pure copper, even for coatings, is now rarely used, and therefore we will not dwell too much on pure copper and move on to its alloys.

Brass.

As many people know, it is an alloy of copper and zinc. Moreover, zinc, as part of this alloy, increases strength and toughness, and, what is important, reduces the cost of the alloy. Brass is widely used because of its relative softness, ductility, it is also excellently processed by cutting, lends itself well to bending, stamping, broaching (pulling) and soldering well.

They produce brass in the form of ingots (castings) of sheets, strips, rods, pipes and wires. And since brass (as well as bronze), unlike copper, has a low coefficient of friction, plain bearings are made from castings (or from bars).

Brass is also widely used in the manufacture of various devices. Well, due to the rather high anti-corrosion resistance of brass, it is widely used in plumbing: various bushings (squeegees, couplings), water taps, valves, etc. And various shims are made from thin sheets of brass.

Well, in addition to corrosion resistance, brass also has excellent thermal conductivity, and therefore radiators are made from it (along with aluminum), radiator pipes and various pipelines in industry are made from tubes.

Bronze.

Bronze is an alloy of copper with aluminum, tin, manganese, silicon, lead and other metals. Bronze is a more brittle and harder material than the brass described above, but it has an even lower coefficient of friction and is therefore more commonly used in plain bearings.

The highest quality and most valuable is tin bronze, which has more useful qualities, since tin in the composition of the alloy increases the mechanical properties of bronze (makes it less brittle) and adds corrosion resistance to bronze, and also makes this alloy even more slippery (increases anti-friction properties) . Tin bronze is used to produce the highest quality and fairly durable plain bearings (along with babbits).

Bronze is well machined and soldered well, but it is more expensive than brass. As mentioned above, plain bearings, various bushings, as well as parts operating under pressure up to 25 kg / cm² are most often made of bronze. They produce bronze, like brass, in the form of bars, strips, wire, tubes, castings, etc.

Babbits.

These alloys have a very low coefficient of friction (if lubricated, then the coefficient of friction is only 0.004 - 0.009) and a rather low melting point (only 240 - 320 degrees). And therefore, babbits are most often used to fill the rubbing surfaces of plain bearings. And since the melting point of babbits is quite low, they are not used in engines, but most often for crankshaft bearings.

In alloys of babbits, the main component is tin, and the highest quality B83 babbit contains 83% tin. Also, substitutes for babbits (for example, B16) with a lower tin content were developed, which are cast on a lead base with the addition of arsenic and nickel - these are BN and BT and other metal alloys.

Lead.

This metal and alloys based on it (for example, solders) has a relatively low melting point (327.46 ° C) and a silvery-white (with a bluish tint) color. It has good toughness (ductility) and excellent casting properties. But it is very soft, easily cut with a sharp knife and even scratched with a fingernail. A rather heavy metal (has a density of 11.3415 g / cm³, and with increasing temperature, its density decreases.

The strength of this metal is very low (tensile strength - 12-13 MPa (MN / m²). It has been known and used since ancient times, as it had a low melting point and was more often used for casting pipelines in the Kremlin and ancient Rome (ibid. in in ancient Rome, its production reached large volumes - about 80 thousand tons per year).

Lead and its compounds are toxic and water-soluble, such as lead acetate, and volatile compounds, such as tetraethyl lead, are especially poisonous. And during the casting of water pipelines in ancient Rome and the Kremlin, no one knew about the harmfulness of lead, and water passing through lead pipelines significantly reduced people's lives.

Now, the main use of lead is casting battery grids, and it is also used to make sheets (chambers) that protect against x-rays in medicine. And alloys of lead, antimony and tin are used in decorative casting (then the figures are covered with copper), as well as for the manufacture of plain bearings (see babbits above) and for various solders for soldering.

Hard metal alloys.

These are alloys based on refractory tungsten, vanadium, titanium carbides and these alloys are characterized by high strength, hardness and wear resistance, even at elevated temperatures. Hard alloys are most often used for the manufacture of working parts of a cutting tool (, milling cutters, etc.).

Cobalt-tungsten hard alloys produced under the brand name from VK2, VK3 and up to VK15. The numbers in the marking indicate the percentage of cobalt in the alloy, and the rest is usually tungsten carbide.

Titanium-tungsten hard alloys the numbers in the marking indicate the percentage of cobalt and titanium, and the rest is tungsten carbide (T5K10, T15K6).

That seems to be all. Of course, in one article it is unrealistic to describe the whole mass of useful and interesting facts related to various metals and metal alloys, but still, I hope that many metallurgists (materials scientists) will forgive me, because it is impossible to grasp the immensity, success to everyone!