EBB113 METALS ALLOYS. Metal Alloys Ferrous SteelCast Iron Low AlloyHigh Alloy Non Ferrous Fe 3 C cementite 1600 1400 1200 1000 800 600 400 0 1234566.7.

EBB113EBB113METALS ALLOYS

Metal AlloysMetal Alloys

Ferrous

Steel Cast Iron

Low Alloy High Alloy

Non Ferrous

Fe3C

cementite

1600

1400

1200

1000

800

600

4000 1 2 3 4 5 6 6.7

L

austenite

+L

+Fe3Cferrite

+Fe3C

+

L+Fe3C

(Fe) Co , wt% C

Eutectic:

Eutectoid:0.76

4.30

727°C

1148°C

T(°C)

Cu

Mg

Al

Ti

SteelsSteelsLow Alloy High Alloy

low carbon <0.25 wt% C

Med carbon0.25-0.6 wt% C

high carbon 0.6-1.4 wt% C

Uses auto struc. sheet

bridges towers press. vessels

crank shafts bolts hammers blades

pistons gears wear applic.

wear applic.

drills saws dies

high T applic. turbines furnaces V. corros. resistant

Example 1010 4310 1040 4340 1095 4190 304

Additions noneCr,V Ni, Mo

noneCr, Ni Mo

noneCr, V, Mo, W

Cr, Ni, Mo

plain HSLA plainheat

treatableplain tool

austenitic stainless

Name

Hardenability 0 + + ++ ++ +++ 0TS - 0 + ++ + ++ 0EL + + 0 - - -- ++

increasing strength, cost, decreasing ductility

•Steels are iron-carbon alloys•Mechanical properties are a function of carbon content and other alloying elements

+ satisfactory, ++good, +++ very good

Low Carbon SteelLow Carbon Steel

Alloys of low carbon steel being produced in the Alloys of low carbon steel being produced in the greatest quantitygreatest quantity

< 0.25wt %C< 0.25wt %C Consists of ferrites and pearlites hence soft and weak Consists of ferrites and pearlites hence soft and weak

but can be treated to achieve high strength but can be treated to achieve high strength Machinable, weldable and cheaper to be producedMachinable, weldable and cheaper to be produced Types: Types:

– i. i. plain low carbon steel -plain low carbon steel - no alloying, variable no alloying, variable tensile strength (TS) (415-550MPa and Yield Strength tensile strength (TS) (415-550MPa and Yield Strength (YS)= 275MPa(YS)= 275MPa

Applications – crankshafts, bolts, hammers, hand Applications – crankshafts, bolts, hammers, hand tools, gears, knivestools, gears, knives

– ii. ii. High strength low alloy (HSLA) –High strength low alloy (HSLA) – with alloying, with alloying, higher TS and YShigher TS and YS

Applications – automobiles opines, nails, wire, pipe Applications – automobiles opines, nails, wire, pipe structural and sheet steel, railway carsstructural and sheet steel, railway cars

Medium Carbon SteelMedium Carbon Steel

0.25 – 0.6 wt %C0.25 – 0.6 wt %C Heat treated to achieve good mechanical Heat treated to achieve good mechanical

propertiesproperties Used in tampered condition (tampered martinsitic)Used in tampered condition (tampered martinsitic) Strength -ductility combination can be tailored by Strength -ductility combination can be tailored by

heat treatment and alloying (with Ni, Cr and Mo)heat treatment and alloying (with Ni, Cr and Mo) Applications: high strength structural components Applications: high strength structural components

– railway wheels, tracks, crankshafts– railway wheels, tracks, crankshafts

High Carbon SteelHigh Carbon Steel

0.6 – 1.4 wt %C0.6 – 1.4 wt %C Hardest, strongest and least ductile carbon Hardest, strongest and least ductile carbon

steelsteel Used in harden and tempered conditionsUsed in harden and tempered conditions Can be alloyed with carbon and other Can be alloyed with carbon and other

metals to form vary hard and wear metals to form vary hard and wear resistance material (e.g. C, Cr, Ni, W, Mo resistance material (e.g. C, Cr, Ni, W, Mo and V)and V)

Applications: cutting tools, drills, saws, Applications: cutting tools, drills, saws, embossing dies, cutlery, paper cutters, embossing dies, cutlery, paper cutters, concrete drill, blacksmith toolsconcrete drill, blacksmith tools

Stainless-SteelsStainless-Steels

Highly resistance alloy to corrosion Highly resistance alloy to corrosion (rusting) in a variety of environment. (rusting) in a variety of environment. Mechanical integrity maintains. Mechanical integrity maintains.

Consisting of iron-carbon and Consisting of iron-carbon and chromium (> 11 wt% Cr needed)chromium (> 11 wt% Cr needed)

Add nickel and molybdenum as wellAdd nickel and molybdenum as well Example 0.08 C, 11.0 Cr, 1.Mn, 0.50 Example 0.08 C, 11.0 Cr, 1.Mn, 0.50

Ni, 0.75 Ti : S40900Ni, 0.75 Ti : S40900 Examples of use of stainless-steel:Examples of use of stainless-steel:

Cast IronsCast Irons

3.0 – 4.5wt % C Liquid at 1150 – 1300oC Easily melted and amenable

to casting

Cast IronsCast Irons

Gray ironGray iron graphite flakesgraphite flakes weak & brittle under tensionweak & brittle under tension stronger under compressionstronger under compression excellent vibrational excellent vibrational

dampeningdampening wear resistantwear resistant

Ductile ironDuctile iron add Mg or Ceadd Mg or Ce graphite in nodules not graphite in nodules not

flakesflakes matrix often pearlite - better matrix often pearlite - better

ductilityductility

True & False (on True & False (on Ferrous Metals)Ferrous Metals)

1.1. Stainless steel consists of iron-carbon and chromiumStainless steel consists of iron-carbon and chromium2.2. Low carbon steel is characterized by high hardness Low carbon steel is characterized by high hardness 3.3. Medium carbon steel is often applied for high Medium carbon steel is often applied for high

strength structural components strength structural components 4.4. Higher carbon steel is weak and ductile Higher carbon steel is weak and ductile 5.5. Due to its high hardness, high carbon steel can be Due to its high hardness, high carbon steel can be

used to make concrete drill, blacksmith tools used to make concrete drill, blacksmith tools 6.6. Cast irons are Cast irons are difficult to be melted

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ACTIVITY (1)

ANSWERSANSWERS

1.1. Stainless steel consists of iron-carbon and chromium Stainless steel consists of iron-carbon and chromium - - TT

2.2. Low carbon steel is characterized by high hardness Low carbon steel is characterized by high hardness - F- F

3.3. Medium carbon Medium carbon steelsteel is often applied for high is often applied for high strength structural components strength structural components

4.4. Higher carbon steel is weak and ductile - FHigher carbon steel is weak and ductile - F5.5. Cast Cast ironirons are s are easier to be melted

Make a mind Make a mind map: ferrous map: ferrous

and non-ferrous and non-ferrous metalmetal

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Discussion (1):

Discussion (2):Discussion (2):Limitations of Ferrous Alloys. Limitations of Ferrous Alloys. Discuss the statements below:Discuss the statements below:

1)Relatively high density2)Relatively low conductivity3)Poor corrosion resistance

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