Ferrous Metals classification

8/12/2019 Ferrous Metals classification

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Plain carbon steels

ame Plain carbon steels Low carbon steels Medium carbonsteels

High carbon stee

omposition

efinitionlt. names

Carbon is the alloying ele that

controls the propC - 1.5%Cu - 0.6%Mn 1.65%Si 0.6%

Largest tonnage of all steels

producedC < 0.25%Also called Mild steels

0.25% < C < 0.6%

Austenized,quenched andtempered toimprove mech prop

C > 0.6%

haracteristics 1. Moderately priced2. Ductile, readily formed3. Can be made into

sheets, bars, rods,wires etc.

1. Relatively soft andweak

2. Cant be hardenedappreciably by heattreatment methods

3. Good formability andweldability

4. Strengthened by coldworking

5. High ductility andtoughness

6. Least expensive7. Contains ferrite and

pearlite

1. Lowhardenability

2. Highstrength

3. Low ductilityandtoughness

1. Hardesstronge

2. Least d3. More w

resistan4. Capabl

holdingsharp e

pplications Automobiles Ball bearings, base

plates etc.

Automobile bodycomponents

Structural shapes Pipelines Buildings and bridges

Railwaywheels andtracks

Gears, crankshafts etc.

Cuttingtools andies

Knivesrazors

Springs High

strengthwires


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Alloy steels

Name Low alloy steels High alloy steels

Composition3% to 4% of one or more alloying elementsAlso called Pearlitic alloy steels

Contains more than 5%of one or more alloyingelements

haracteristics 1. Similar microstructure as that of PCS andrequires similar heat treatment processes

2. Eutectoid pearlite structure3. Alloying elements provide enhanced properties4. They increase strength without loss in toughness

and increased hardenability

1. They have diff microstructure andrequire diff heat treatments than thatof PCS

2. Austentic, martensitic or precipitatedcarbides structures are possible

Types AISI HSLA Tool and diesteels

Stainless steel

1. American iron and steelinstitute steels

2. Construction or structuralsteels

3. They have less than 5% oftotal addition of elements

4. Cr, Ni, Cu, Mn, Mo, V etc5. Has very good hardenability

1. Highstrengthlow alloysteels

2. Microalloyedsteels

3. Al, Nband V

1. High qualityalloys usedfor tools anddies

2. Hardenability3. Wear

resistance4. Resistance to

softening onheating

1. Used forimprovingcorrosionresistance


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Stainless steels

Name Austenitic SS Ferritic SS Martensitic SS

omposition C - 0.03% to 0.15%Mn 2% to 10%Si - 1% to 2%Cr 16% to 26%Ni - 3.5% to 22%

C 0.08% to 0.10%

Mn 1% to 1.5%Si 1%Cr 12% to 25%

C 0.1% to 1.5%

Mn 1%Si 1%Cr 12% to 25%

Properties 1. Highest corrosion resistance2. Good strength and scale

resistance at high temperatures3. Non magnetic4. Good ductility at 0C5. Very tough and can be welded,

forged or rolled

1. Magnetic2. Good ductility3. Great strength,

toughness and goodresistance to corrosion

4. Can be welded, forged,rolled and machined

1. Good hardness, ductiland thermal conductiv

2. Good toughness andcorrosion resistance

hort notes Austenite structure at roomtemperatures

Produced in greatest tonnage Contains both Cr and Ni, the

tendency of Ni to reduce thecritical temp overrides theopposite effect of Cr thus acompletely austenitic structure

is possible C < 0.15% to minimizeformation of Cr carbides, as itwould decrease the corrosionresistance

Carbide form when the metalcools slowly form high temparound 500 to 700C

The above temp is attainedduring weld processes andresults in formation of carbidesand may lead to failure

This type of corrosion failure iscalled weld decay. Titanium orniobium is added to prevent this

Nitride particles improvestrength, hardness and wearresistance

Ferritic structure alltemp till its meltingpoint

Cannot be heat treated Can be strengthened

by work hardening

They contain 12 to 25of Cr and 0.1 to 1.5%

The presence of carborestores the to gammtransition

They can be heated toaustenitic temperatureand will form martens

upon cooling


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pplications Aircraft industry (engine parts) Heat exchanger Cooking utensils Trailers and railway cars

Lining for petroleumindustries

Heating elements forfurnaces

Screws

Oil burner parts Interior decoration

Pumps and valve parts Rules and tapes Turbine buckets Surgical instruments

Other important alloy steels

Name Tool steels HSLA steels Maraging steelsomposition C 0.10% to 1.60%

Mn 0.10% t0 0.60%

Si 0.10% to 1.20%Cr 0.15% to 13%Ni 0.10% to 0.50%

C 0.10 to 0.25%Mn 0.50 to 1.25%

Si 0.10 to 0.30%Cr 0.01%V 0.01 to 0.02%P 0.04%S 0.05%Cu 0.20%

C < 0.05%Ni 18%

Co 7%And small amounts of other elemensuch as titanium

Properties 1. Good toughness2. Good wear resistance3. Very good machinability4. Slight change of form

during hardening5. Little risk of cracking

during hardening6. Resistance to softening

and heating7. Resistance to

decarburization8. A definite hardening

temp9. A definite cooling rate

during hardening

1. High yield strength2. Can be welded without

becoming brittle3. They are very light4. High corrosion resistance5. Ductile formable and

machinable

1. Very high tensile and impastrength

2. Considerable toughness anhigh strength is muchsuperior to constructionalsteels

3. Suitable for surfacehardening and nitriding

4. Can be welded, if welding followed by full solution aageing treatment

hort notes Used to make tools anddies for cutting and

forming Designed to provide

wear resistance andtoughness combinedwith strength

Basically high carbonalloys whos chemistryprovides wear resistance

High strength low alloysteels or micro alloyed

steels Reduces weight and

increases strength Structural or

constructional alloy steels They have twice the yield

strength against PCS

Low carbon and high alloysteels

Very high strength materia Tensile strength upto

1900MPa can be obtained The composition of these

steels forms martensite upocooling


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makes grey ironbrittle

Shape size anddistribution ofthe graphiteflakes have asignificant effecton the overallproperties

Most white CIare hypoeutectic

appears likepop corn

Ferriticmalleable CI :its heatedbeyond uppercriticaltemperatureand held therefor a prolongedtime so that allthe cementiteturns intographite andon coolingthrough theeutectoidreaction ferriticmatrix ifformed

Pearliticmalleable CI :the white castiron is cooledmore rapidlyfrom the uppercriticaltemperatures

such that thecarbon will notbe able to turninto graphiteand will resultin a pearliticstructure.

haracteristics 1. Excellentcompressivestrength, compstrength is fivetimes its tensilestrength

2. Good torsionaland shearstrengths

3. Good corrosionresistance

4. Excellentfluidity. Hence,

1. Very hard andbrittle

2. High abrasionresistance

3. High tensile andlow compressivestrength

4. It cant bemachined due toits hardness

5. Can be casted insand moulds

1. Good ductilityandmalleability

2. High yield andtensile strength

3. Not brittle4. High youngs

modulus andlow co eff ofthermalexpansion

5. Excellentimpact and

1. Excellent ductensile and yiestrengths

2. Good toughne3. Good fatigue

strength4. Good impact

strength5. Good hardnes

and high modof elasticity

6. Corrosionresistant


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can be cast intocomplex shapes

5. Good wearresistance

6. Excellentmachinability(better thansteel)

7. Outstandingvibration andsound dampingcapacity

fatiguestrength

6. Good wearresistance andvibrationdamping

7. Excellentmachinability

7. Excellentcastability andwear resistanc

8. Resists oxidatat hightemperatures

9. Goodmachinability

Application Machine toolbodies

Engine blocks Engine cylinders Brake drums Cam shafts Ingot moulds

Raw material forthe productionof malleable castiron

Wear plates,pump linings

Used for interiorcastings

Brake shoes,pedals

Wheel hubs,axle housing

Transmissiongears and doorhinges

Valves, pumpbodies

Crank shafts,gears, pinions

Rollers, rockearms

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Ferrous Metals classification

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