Cast iron. Classification of cast iron Yu.A. Dementiev Regional state educational institution of primary vocational education “Vocational school. Presentation on the topic of the use of cast iron in mechanical engineering

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Blitz Poll

1. Fluidity - the ability of metals and alloys in the molten state to fill the cavities of the mold (+) 2. Crystallization is the transition of a metal from a solid state to a liquid state (-) 3. Creep - the ability of a material to slowly and continuously plastically deform .... (+) 4. Malleability - the ability of metals and alloys to be subjected to various machining methods and cutting tools. (-) 5. Shrinkage - the ability of metals and alloys to shrink after solidification. (+)

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Cast iron is an alloy of iron with carbon, the carbon content is more than 2.14%.

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IMPURITIES

USEFUL HARMFUL MANGANESE - increases the hardness of cast iron SILICON - increases strength and toughness, improves casting properties .. SULFUR - reduces strength, worsens casting properties PHOSPHORUS - increases brittleness

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Classification and properties of cast iron.

depending on the degree of graphitization, which determines the type of fracture, - into gray, white and half (or bleached); depending on the form of graphite inclusions - for cast iron with lamellar, spherical (high-strength cast iron), vermicular and flaky (ductile cast iron) graphite; depending on the purpose - for structural and cast iron with special properties; by chemical composition - into alloyed and unalloyed.

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Cast iron classification:

1. According to the structure: 1) Primary cast iron - white or pig iron (c \u003d 3.7% - 4.5%) Fe3C - cementite for steel production. 2) Gray or cast iron. brand: SCH - 15 Marking of gray cast irons: Letters SCh - (denoting gray cast iron) Numbers - tensile strength, kgf / mm2; Example SC - 18 - Gray cast iron, 18 - - tensile strength, 18 kgf / mm2;

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3) Ductile iron KCh - 40 - 10, KCh 40-20 Marking of ductile irons: Letters KCh - (indicate ductile iron) Numbers - (1 - number - tensile strength, kgf / mm2, 2 - relative elongation,%) Example KCh - 35 - 10 - Ductile iron, 35 - tensile strength, 35kgf / mm2, 10 - relative elongation, 10%)

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4) Ductile cast iron VCh-35 Marking of ductile irons: Letters VCh - (indicate ductile iron) Numbers - (1 - number of tensile strength, kgf / mm2, 2 - relative elongation,%) Example VCh - 42 - 12 - Ductile iron , 42 - tensile strength, 35kgf / mm2, 12 - relative elongation, 10%)

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5) Anti-friction cast iron - obtained on the basis of gray, high-strength and malleable cast irons. Marking of anti-friction cast iron: The letters АЧ– (indicate anti-friction cast iron) Numbers - grade number according to GOST Example AChS - 2, anti-friction gray cast iron, 2 - grade number according to GOST.

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6) Alloy cast irons - cast irons into which special elements are introduced to improve the properties of cast irons.

X - CHROME; D - COPPER T - TITANIUM M - MOLYBDENUM N - NICKEL U - ALUMINUM C - SILICON G - MANGANESE F - VANADIUM

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ChN 1KhMD - alloyed cast iron, nickel content - 1%, molybdenum and copper content - up to 1.5%

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Answer form: a combination of the question number and the letter of the answer. Answer options: a) gray b) white c) malleable d) high-strength

What is the name of cast iron, in which carbon is contained in the form of cementite? What is the name of cast iron obtained by slow cooling? What is the name of cast iron with spherical inclusions? What cast iron is converted into steel? What is the name of cast iron obtained by annealing? What is the name of cast iron, in which carbon is in the form of graphite plates? What is the name of the cast iron obtained as a result of modification? What is the name of cast iron with graphite in the form of flakes? Which cast iron has high casting properties? Which cast iron has high ductility?

Classification of cast iron according to the state diagram Cast irons with C content from 2.14 to 4.3% - Hypoeutectic cast irons with C content from 2.14 to 4.3% - Hypoeutectic cast irons with C=4.3% content - Eutectic cast irons with C=4.3% content - Eutectic cast irons with C content from 4.3 to 6.67% - hypereutectic cast irons with C content from 4.3 to 6.67% - hypereutectic

Marking of white cast iron White cast irons are marked according to the method of their further remelting into steel. M0 B1 T1 M-Martenovsky M1 B2 T2 B-Bessemerovsky M2 B3 T3 T-Tomaovsky M3 0,1,2,3-series number Purpose: for further remelting into steel and obtaining malleable cast iron cast iron

Gray cast iron (foundry) Gray cast irons contain free carbon in the form of graphite plates. They have good casting properties (high fluidity, low shrinkage - 1%), are well machined, but have very low ductility up to 1%. Gray cast irons are marked by strength MF

Marking of gray cast iron unmodified (contain large graphite plates that reduce strength) SCH10 SCH15 SCH20 SCH25 unmodified (contain large graphite plates that reduce strength) SCH10 SCH15 SCH20 SCH25 Purpose: kettlebells, dumbbells, frying pans, batteries, baths Purpose: weights, modified dumbbells, frying pans, batteries, bathtubs (contains crushed graphite plates) MF30 SC50 SC35 SC55 SC40 SC60 SC45 modified (contains crushed graphite slabs) SC30 SC50 SC35 SC55 SC40 SC60 SC45 Purpose: various parts of machines operating under stationary conditions Purpose: various parts of machines operating under stationary conditions

Annealing malleable iron In an oxidizing environment scrap iron ore scale T= T view. = min V cool.-together with the furnace Result: get black-heart pearlitic cast iron get higher strength values ​​CCH CCH 60-3 In an oxidizing environment, scrap iron ore scale T= T species. = min V cool.-together with the furnace Result: black-hearted pearlitic cast iron is obtained higher strength values ​​are obtained CN CN 60-3 In a neutral medium 1) T viz. max) T view. = 50-60 h Negro decreases. 750 Result: white-hearted ferritic cast iron KN In a neutral environment 1) T spec. max) T view. = 50-60 h Negro decreases. 750 Result: white-hearted ferritic cast iron KCh 37-12

Ductile irons Ductile irons contain free carbon in the form of graphite globules, which are obtained by inoculation with magnesium. Marking: VCh b-8 VCh 60-2 VCh VCh 60-2 VCh Purpose: machine parts (crankshaft, gears, couplings, wheel hubs) Ductile irons are substitutes for steel.

Ductile Iron Contains free carbon in the form of graphite flakes. Marked: CN G kg/mm-b% Purpose: various machine parts manufactured in large batches Production of ductile iron 1) Casting from white cast iron with a wall thickness of up to 30 mm 2) Heat treatment (annealing)

slide presentation

Slide text: Topic: "Cast irons. Classification of cast irons"

Slide text: 1. Fluidity - the ability of metals and alloys in the molten state to fill the cavities of the mold (+) 2. Crystallization is the transition of a metal from a solid state to a liquid state (-) 3. Creep - the ability of a material to slowly and continuously plastically deform .... (+) 4. Malleability - the ability of metals and alloys to be subjected to various machining methods and cutting tools. (-) 5. Shrinkage - the ability of metals and alloys to shrink in size after solidification. (+) Blitz survey

Slide text: Cast iron is an alloy of iron and carbon, the carbon content is more than 2.14%.

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Slide text: USEFUL HARMFUL IMPURITIES MANGANESE - increases the hardness of cast iron SILICON - increases strength and toughness, improves casting properties .. SULFUR - reduces strength, worsens casting properties PHOSPHORUS - increases brittleness

Slide text: depending on the degree of graphitization, which determines the type of fracture, - into gray, white and half (or bleached); depending on the form of graphite inclusions - for cast iron with lamellar, spherical (high-strength cast iron), vermicular and flaky (ductile cast iron) graphite; depending on the purpose - for structural and cast iron with special properties; by chemical composition - into alloyed and unalloyed. Classification and properties of cast iron.

Slide text: Classification of cast irons: 1. By structure: 1) Primary cast iron - white or pig iron (c \u003d 3.7% - 4.5%) Fe3C - cementite for steel production. 2) Gray or cast iron. brand: SCH - 15 Marking of gray cast irons: Letters SCh - (denoting gray cast iron) Numbers - tensile strength, kgf / mm2; Example SC - 18 - Gray cast iron, 18 - - tensile strength, 18 kgf / mm2;

Slide text: 3) Ductile cast iron KCh - 40 - 10, KCh 40-20 Marking of ductile irons: Letters KCh - (indicate ductile iron) Numbers - (1 - number - tensile strength, kgf / mm2, 2 - relative elongation, %) Example CN - 35 - 10 - Ductile iron, 35 - tensile strength, 35kgf / mm2, 10 - relative elongation, 10%)

Slide text: 4) Ductile cast iron VCh-35 Marking of ductile irons: Letters VCh - (indicate ductile iron) Numbers - (1 - number of tensile strength, kgf / mm2, 2 - relative elongation,%) Example VCh - 42 - 12 - Ductile iron, 42 - tensile strength, 35kgf / mm2, 12 - relative elongation, 10%)

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Slide text: 5) Anti-friction cast iron - obtained on the basis of gray, ductile and ductile cast irons. Marking of anti-friction cast iron: The letters АЧ– (indicate anti-friction cast iron) Numbers - grade number according to GOST Example AChS - 2, anti-friction gray cast iron, 2 - grade number according to GOST.

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Slide text: X - CHROME; D - COPPER T - TITANIUM M - MOLYBDENUM N - NICKEL U - ALUMINUM C - SILICON G - MANGANESE F - VANADIUM 6) Alloyed cast irons - cast irons into which special elements are introduced to improve the properties of cast irons.

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Slide text: ChN 1KhMD - alloyed cast iron, nickel content - 1%, molybdenum and copper content - up to 1.5%

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Slide text: What is the name of cast iron, in which carbon is contained in the form of cementite? What is the name of cast iron obtained by slow cooling? What is the name of cast iron with spherical inclusions? What cast iron is converted into steel? What is the name of cast iron obtained by annealing? What is the name of cast iron, in which carbon is in the form of graphite plates? What is the name of the cast iron obtained as a result of modification? What is the name of cast iron with graphite in the form of flakes? Which cast iron has high casting properties? Which cast iron has high ductility? Answer form: a combination of the question number and the letter of the answer. Answer options: a) gray b) white c) malleable d) high-strength

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Slide text: 1.b 2.a 3.d 4.b 5.c 6.a 7.d 8.c 9.a 10.c Answers:

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Slide text: 1. Cast iron Timber transportation by river 2. Metal Main component of cast iron 3. Non-metal Undesirable component of cast iron Crossword "Association"

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Slide text: 4. Alloy additives Alloys of iron with silicon, manganese 5. Alloying element Leather 6. Non-metal in cast iron Component rock

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Slide text: 7. Non-metal The main component of cast iron 8. Alloying element Outstanding personality 9. Alloying element Forest

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Slide text: Message: “Cast irons used in mechanical engineering” Learn the classification of cast irons and their marking. Homework.

White cast iron White cast irons are characterized by the presence of carbon in the form of cementite (Fe 3 C). White cast iron is characterized by: high hardness brittleness high wear resistance Generally white cast iron is not machined and is used for conversion into malleable cast iron.

Properties of gray cast iron Gray cast iron has high casting properties and is well processed by cutting. Widely used in mechanical engineering. To improve the mechanical properties, gray cast iron is modified by adding aluminum or calcium.

Anti-friction cast iron Anti-friction cast irons are produced on the basis of gray, ductile and ductile cast irons. AChS cast irons are alloyed with: chromium (0.2-0.4%), nickel (0.2-0.4%), copper (0.3-2%), aluminum (0.4-0.8%). AChV cast irons are alloyed with: copper (0.7%), magnesium (0.03%). AChK cast irons are alloyed with: copper (1-1.5%).

Heat-resistant cast iron By introducing alloying elements cast irons are created with special physical and chemical properties. Heat-resistant cast iron is designed for operation at temperatures up to 600 ° C. Alloyed with nickel, chromium, manganese. Heat-resistant cast iron is used for the manufacture of parts gas turbines, pumps, internal combustion engines.

Marking of heat-resistant cast irons The designation of the grade of heat-resistant cast iron includes: the letter H (denoting "cast iron"); letters H, X, G (indicate alloying elements nickel, chromium, manganese); the letter Ш (indicates that graphite has a spherical shape); numbers behind the letter (indicate the percentage of alloying elements).

Heat Resistant Cast Iron Heat resistant cast iron has the ability to resist oxidation when elevated temperatures. Alloyed with chromium, silicon, aluminum. Heat-resistant cast iron retains its properties at temperatures up to °C.

Marking of heat-resistant cast irons The designation of the grade of heat-resistant cast iron includes: letters ZHCH (denoting "heat-resistant cast iron"); letters X, C, Yu (denote alloying elements chromium, silicon, aluminum); the letter W (indicates that the graphite has a spherical shape); numbers (indicate the percentage of alloying elements).

Marking of corrosion-resistant cast irons The designation includes: the letter Ch (denoting "cast iron"); letters X, T, M, D, H (denote alloying elements chromium, titanium, molybdenum, copper, nickel); the letter Ш (indicates that graphite has a spherical shape); numbers (indicate the percentage of alloying elements).

3. White cast iron contains carbon in the form of: a) cementite; b) nodular graphite; c) lamellar graphite.

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Cast iron is an iron-carbon alloy with a carbon content of >2.14% and impurities in tenths of a percent. In addition, cast iron contains impurities in tenths: silicon, manganese, sulfur, phosphorus, etc. In order to improve the properties, alloying elements such as chromium, nickel, copper, etc. can be introduced into cast irons.

Types of cast iron

Gray cast iron Gray cast iron is an alloy of iron, silicon (from 1.2-3.5%) and carbon, also containing constant impurities of Mn, P, S. In the structure of such cast irons, most or all of the carbon is in the form of lamellar graphite. The fracture of such cast iron due to the presence of graphite has a gray color. Gray cast iron is used for the manufacture of lightly loaded parts operating in light conditions. For example, gearbox housings, pumps, electric motors, various covers, heating batteries, etc.

White cast iron White cast iron is cast iron in which carbon is chemically combined with iron. Carbon in white cast iron is in the form of cementite Fe3C - a bound state. Cementite gives the cast iron fracture a shine, while graphite gives it a gray color. Therefore, cast iron, in which all carbon is in a bound state, is called white cast iron. Relatively soft and machinable. Softness gives free carbon.

Malleable cast iron Malleable cast iron is obtained by long-term annealing of white cast iron, which results in the formation of flake-shaped graphite. The metal base of such cast iron: ferrite and less often perlite. Malleable cast iron got its name from its increased ductility and toughness (although it is not subjected to pressure treatment). Ductile iron has high tensile strength and high impact resistance. Parts of complex shape are made from ductile iron: rear axle housings of automobiles, brake pads, tees, squares, etc.

Ductile iron has nodular graphite in its structure, which is formed during the crystallization process. Nodular graphite does not weaken the metal base as much as lamellar graphite, and is not a stress concentrator. In cast iron, part of the carbon (more than 0.8%) is contained in the form of cementite. The structural components of such cast iron are perlite, ledeburite and lamellar graphite. Ductile Iron, Half Cast Iron

Cast iron is widely used in the manufacture of products for various purposes. The main qualities of cast iron are low cost, good casting qualities, strength and hardness. Cast iron is used where it is necessary to obtain parts of complex shape and sufficient strength. For example, machine beds, body parts or artistic cast-iron fences. Everyone is well aware of the artistic decorations of the embankments of St. Petersburg, made of cast iron. The openwork cast gates of the Winter Palace, as well as other monuments, are no less beautifully decorated. Scope of cast iron

In the automotive industry, cast iron is used to produce cylinder blocks for internal combustion engines (on modern production compacted graphite iron is used), as well as crankshafts diesel engines. Cast iron is widely used in plumbing fixtures - cast iron is used to make bathrooms, sinks and kitchen sinks, as well as heating radiators, pipes and fittings. For example, cast iron bathrooms are highly valued by connoisseurs for their reliability, durability and unpretentiousness in operation. Such bathrooms can serve for decades, keeping the original look unchanged.