Ferrous Metals and Ferrous Metals and AlloysAlloys

By-By- Abhishek SinghAbhishek Singh ME-2ME-2 14014400041401440004

ContentsContents ferrous metalsferrous metals pig ironpig iron cast iron cast iron types of cast irontypes of cast iron wrought ironwrought iron steelssteels Effects of elements in steelsEffects of elements in steels carbon steelcarbon steel alloy steelalloy steel

Ferrous MetalsFerrous Metals

Ferrous metals are those in which the Ferrous metals are those in which the chief constituent is iron . Hence iron , chief constituent is iron . Hence iron , steel and their alloys fall under these steel and their alloys fall under these category.category.

26th element Iron or Ferrous 55.85 Atomic Mass

Pig IronPig Iron it is crude form of iron and used as a it is crude form of iron and used as a

raw material for production of various raw material for production of various other metals such as cast iron, steel other metals such as cast iron, steel etc.etc.

The main raw materials required are –The main raw materials required are –– iron oreiron ore– CoalCoal– flux flux

IronmakingIronmaking

Blast FurnaceBlast Furnace

Working Working The three raw materials are dumped into a blast The three raw materials are dumped into a blast

furnace.furnace.

Hot air (2000*F) is blasted into the furnace, which Hot air (2000*F) is blasted into the furnace, which helps drive the chemical reaction. The coke helps drive the chemical reaction. The coke forms CO and the CO reduces the iron oxide to forms CO and the CO reduces the iron oxide to iron.iron.

The slag floats to the top and the metal is The slag floats to the top and the metal is transferred to molds and cools. It is now pig iron, transferred to molds and cools. It is now pig iron, ready for more iron work or steelmaking. ready for more iron work or steelmaking.

Cast Iron Cast Iron

Contains 2%-4% of carbon Contains 2%-4% of carbon Very hard and brittleVery hard and brittle Strong under compressionStrong under compression Suitable for casting [can be pour Suitable for casting [can be pour

at a relatively low temperature]at a relatively low temperature] Engine block, engineer vices, Engine block, engineer vices,

machine partsmachine parts

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Types of cast ironTypes of cast iron Gray cast iron Gray cast iron White cast ironWhite cast iron Malleable cast ironMalleable cast iron Nodular cast ironNodular cast iron Alloy cast ironAlloy cast iron

Gray Cast IronGray Cast Iron Compositions- (other than iron)Compositions- (other than iron)

– Carbon= 3 - 4.5 %Carbon= 3 - 4.5 %– Silicon= 1 – 2.75 %Silicon= 1 – 2.75 %– Manganese = 0.4 – 1 %Manganese = 0.4 – 1 %– Phosphorous = 0.15 – 1 %Phosphorous = 0.15 – 1 %– Sulphur = 0.02 - 0.15 % Sulphur = 0.02 - 0.15 %

Uses – Uses – – cylinder blocks , fly wheel , pipes , cylinder blocks , fly wheel , pipes ,

etcetc

White Cast IronWhite Cast Iron Compositions –

– carbon = 1.75 – 2.5 %– silicon = 0.85 – 1.2 %– manganese = 0.1 - 0.4 %– phosphorous = 0.05 - 0.2 %– sulphur = 0.12 – 0.35 %

Uses-– Use as raw materials , break shoes ,

pumps

Malleable Cast Iron Obtain from white cast iron by

annealing process It separate free graphite into

nodular form Uses-

– hubs of wagon wheel , pipes fittings , etc

Nodular Cast IronNodular Cast Iron Also known as ductile cast ironAlso known as ductile cast iron Can be produced in thicker part Can be produced in thicker part

than malleable cast ironthan malleable cast iron uses – uses –

– in cast parts where density and in cast parts where density and pressure tightness is highly desired pressure tightness is highly desired quality . Ex – valves , hydraulic quality . Ex – valves , hydraulic cylinderscylinders

Alloy Cast Iron Produced by adding alloying Produced by adding alloying

elements such as Ni , Cr , Mo , elements such as Ni , Cr , Mo , Cu , Si etcCu , Si etc

These elements provide more These elements provide more strength, corrosion resistance etc strength, corrosion resistance etc

Uses-Uses-– piston , piston rings , parts of piston , piston rings , parts of

crushing and grinding etccrushing and grinding etc

Wrought IronWrought Iron Purest form of iron contain atleast Purest form of iron contain atleast

99.5 % iron99.5 % iron It is tough , malleable ,ductile but It is tough , malleable ,ductile but

cannot withstand sudden and cannot withstand sudden and excessive shocksexcessive shocks

Uses –Uses –– crane hooks , railway cuppling , etccrane hooks , railway cuppling , etc

SteelmakingSteelmaking

Steel Steel It is classified into two types –It is classified into two types –

– carbon steels carbon steels – Alloy steelsAlloy steels

Effects of Elements in Effects of Elements in SteelsSteels CarbonCarbon: improves hardenability, strength, : improves hardenability, strength,

hardness, and wear resistance; it reduces hardness, and wear resistance; it reduces ductility, weldability, and toughness.ductility, weldability, and toughness.

ChromiumChromium: improves toughness, : improves toughness, hardenability, wear and corrosion resistance, hardenability, wear and corrosion resistance, and high-temperature strength; it increases the and high-temperature strength; it increases the depth of the hardness penetration resulting depth of the hardness penetration resulting from heat treatment by promoting from heat treatment by promoting carburizationcarburization

CobaltCobalt: improves strength and hardness at : improves strength and hardness at

elevated temperatures.elevated temperatures. Calcium Calcium: Deoxidizes : Deoxidizes steels, improves toughness, and may improve steels, improves toughness, and may improve formability and machinability.formability and machinability.

CopperCopper: improves resistance to atmospheric : improves resistance to atmospheric corrosion and, to a lesser extent, increases corrosion and, to a lesser extent, increases strength with little loss in ductility; it adversely strength with little loss in ductility; it adversely affects the hot-working characteristics and affects the hot-working characteristics and surface quality.surface quality.

LeadLead: improves machinability; it causes liquid-: improves machinability; it causes liquid-metal embrittlement.metal embrittlement.

MagnesiumMagnesium: has the same effects as cerium.: has the same effects as cerium.

ManganeseManganese: improves hardenability, strength, : improves hardenability, strength, abrasion resistance, and machinability; it abrasion resistance, and machinability; it deoxidizes the molten steel, reduce shot deoxidizes the molten steel, reduce shot shortness, and decreases weldability.shortness, and decreases weldability.

MolybdenumMolybdenum: improves hardenability, wear : improves hardenability, wear resistance, toughness, elevated-temperature resistance, toughness, elevated-temperature strength, creep resistance, and hardness; it strength, creep resistance, and hardness; it minimizes temper embrittlement. minimizes temper embrittlement.

NickelNickel: improves strength, toughness, and : improves strength, toughness, and corrosion resistance; it improves corrosion resistance; it improves hardenability.hardenability.

PhosphorusPhosphorus: improves strength, : improves strength, hardenability, corrosion resistance, and hardenability, corrosion resistance, and machinability; it severely reduces ductility machinability; it severely reduces ductility and toughness.and toughness.

SiliconSilicon: improves strength, hardness, : improves strength, hardness, corrosion resistance, and electrical corrosion resistance, and electrical conductivity; it decreases magnetic-conductivity; it decreases magnetic-hysteresis loss, machinability, and cold hysteresis loss, machinability, and cold formability.formability.

Carbon SteelsCarbon Steels Carbon steels are group Carbon steels are group

by their percentage of by their percentage of carbon content per carbon content per weight. The higher the weight. The higher the carbon content the carbon content the greater the hardness, greater the hardness, strength and wear strength and wear resistance after heat resistance after heat treatment. treatment.

Low-carbon steelLow-carbon steel,, also also called mild steels, has called mild steels, has less than 0.30% carbon. less than 0.30% carbon. Used in everyday Used in everyday industrial products like industrial products like bolts, nuts, sheet, plate bolts, nuts, sheet, plate and tubes.and tubes.

High Carbon Steel Nails

Medium-carbon steelMedium-carbon steel has 0.15- has 0.15- 0.30% to 0.60% carbon. Used for 0.30% to 0.60% carbon. Used for jobs requiring higher strength such jobs requiring higher strength such as machinery, automotive as machinery, automotive equipment parts, and metalworking equipment parts, and metalworking equipment.equipment.

High-carbon steelHigh-carbon steel has 1- 0.60 % has 1- 0.60 % carbon. Used parts that require the carbon. Used parts that require the highest strength, hardness, and highest strength, hardness, and wear resistance. Once manufactured wear resistance. Once manufactured they are heat treated and temperedthey are heat treated and tempered

Alloy SteelsAlloy Steels Alloy steelsAlloy steels are steels that are steels that

contain significant amounts of contain significant amounts of alloying elements.alloying elements.

– Nickel alloy steel– Chromium alloy steel– Stainless steel– high speed steel

Nickel Alloy SteelNickel Alloy Steel compositions – compositions –

– Nickel = 2 – 5 %Nickel = 2 – 5 %– Carbon = 0.1 – 0.5 %Carbon = 0.1 – 0.5 %

imposes tensile strength, imposes tensile strength, improves resistance to corrosion improves resistance to corrosion and heatand heat

Uses –Uses –– boiler tube , crank shaft , spark plug boiler tube , crank shaft , spark plug

for patrol enginefor patrol engine

Chromium Alloy SteelChromium Alloy Steel compositions –compositions –

– Chromium = 0.5 – 2 %Chromium = 0.5 – 2 %– Carbon = 0.1 – 1.5 %Carbon = 0.1 – 1.5 %

increases strength , hardness , increases strength , hardness , resistance to corrosion resistance to corrosion

uses – uses – – dies , axles , gearsdies , axles , gears

Stainless SteelsStainless Steels

Stainless steels Stainless steels are are primarily know for primarily know for their corrosion their corrosion resistance, high resistance, high strength, and strength, and ductility and ductility and chromium content.chromium content.

It contain 12 – 14 % It contain 12 – 14 % Cr and 0.1 – 0.35 % Cr and 0.1 – 0.35 % carboncarbon

Stainless SteelsStainless Steels

The reason for the name stainless is due to the The reason for the name stainless is due to the fact that in the presence of oxygen, the steel fact that in the presence of oxygen, the steel develops a thin, hard, adherent film of develops a thin, hard, adherent film of chromium. chromium. – Even if the surface is scratched, the protective film is Even if the surface is scratched, the protective film is

rebuilt through passivation.rebuilt through passivation. For passivation to occur there needs to be a minimum For passivation to occur there needs to be a minimum

chromium content of 10% to 12% by weight.chromium content of 10% to 12% by weight.

Stainless SteelsStainless Steels Stainless steels tend to have lower Stainless steels tend to have lower

carbon content since increased carbon content since increased carbon content lowers the corrosion carbon content lowers the corrosion resistance of stainless steels.resistance of stainless steels.– Since the carbon reacts with chromium Since the carbon reacts with chromium

it decreases the available chromium it decreases the available chromium content which is needed for developing content which is needed for developing the protective film.the protective film.

Stainless SteelsStainless Steels Using stainless steels as reinforcing bars, has Using stainless steels as reinforcing bars, has

become a new trend, in concrete structures such become a new trend, in concrete structures such as highways buildings and bridges. as highways buildings and bridges. – It is more beneficial than carbon steels because it is It is more beneficial than carbon steels because it is

resistant to corrosion from road salts and the concrete resistant to corrosion from road salts and the concrete itself.itself.

Rebar corrosion in concrete

High Speed SteelHigh Speed Steel Compositions –Compositions –

– tungsten = 18 %tungsten = 18 %– chromium = 4 %chromium = 4 %– vanadium = 1 %vanadium = 1 %

Acts as a cutting tools Acts as a cutting tools at high temperature at high temperature

Uses – Uses – – cutting , drilling , lathe cutting , drilling , lathe

tools, etctools, etc