Metal Alloys ( 금속 합금 )

Metal AlloysMetal AlloysManufacturing ProcessesManufacturing Processes

© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU1

Metal Alloys ( 금속 합금 )

Associate Professor Su-Jin Kim

School of Mechanical EngineeringGyeongsang National University


© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU

Metal Alloys( 금속 )

Metal Alloy( 금속합금 )

Ferrous( 철 )

Nonferrous( 비철금속 )

Steels( 강 )

C<1.4%

Cast Irons( 주철 )

3.0~4.5%

Copperalloy

Aluminumalloy

…alloy



Ferrous Alloys ( 철 )

• Ferrous alloys are useful metals in terms of mechanical, physical and chemical properties.

• Alloys contain iron Fe (density 7.9 g/cm3) as their base metal.

• Carbon steels (700W/kg) are least expensive of all metals while stainless steels (7,000W/kg) is costly.



Steels ( 강 )

Composition and processing are controlled in a manner that is suitable for different applications.

Several elements are added to steels for Strength( 강도 ), Hardness( 경도 ), Toughness( 인성 )Hardenability( 경화성 ), Wear resistance( 내마모성 )Workability( 가공성 ), Weldability( 용접성 ), Machinability( 절삭성 )



SteelsCarbon steel

( 탄소강 )High alloy steel

( 고합급강 )

Low carbon( 저탄소강 )

C < .25 %

Med carbon( 중탄소강 )

.25-.60%

High carbon( 고탄소강 ).60-1.40%

Plain HSLA( 고강도 )

PlainHeat

Treatable( 열처리 )

Plain Tool( 공구 )

Stainless( 스테인리스 )

auto struc. sheet

bridges towers press. vessels

crank shafts bolts hammers

pistons gears wear applic.

wear applic.

drills saws dies

high T turbines furnaces corrosion resistant

strength, hardenability, costductility

1010S10C

4310SNCM10

1040S40C

4340SNCM40

1095 4190KD11

304, 409SUS304



Steels

AISI/SAE JIS/KS Nomenclature( 조성 ) for steels

10xx SxxC Plain Carbon Steels ( 탄소강 )40xx SMoxx Mo (.2 ~ .3%)41xx SCMxx Cr (.80~1.1), Mo (.15~.25)43xx SNCMxx Ni (1.65 ~ 2.0), Cr (.4 ~ .9), Mo (.2~.3)

where xx is % C x 100Ex) 1045 S45C – Plain Carbon Steel with 0.45 % C

Stainless Steel 304 SUS304 Cr (11%~)



Carbon steels ( 탄소강 )

• Classified as low, medium and high:1. Low-carbon steel or mild steel, C< 0.25%, bolts, nuts

and sheet plates.2. Medium-carbon steel, 0.25% ~ 0.60%, machinery,

automotive and agricultural equipment.3. High-carbon steel, C > 0.60%, springs, cutlery, cable.

• Ex) S10C S45C



Alloy steels ( 합금강 )

• Steels containing significant amounts of alloying elements.

• Structural-grade alloy steels used for construction industries due to high strength.

• Other alloy steels are used for its strength, hardness, resistance to creep and fatigue, and toughness.

• It may heat treated to obtain the desired properties.



HSLA

High-strength low-alloy steels ( 고강도 저합금강 )• Improved strength-to-weight ratio.• Used in automobile bodies to reduce weight and in

structural plate.



Tool & Die steels ( 공구강 금형강 )

• Designed for high strength, impact toughness, and wear resistance at a range of temperatures.

Ex) SKD11 SKD61 NAK80



Stainless steels

• Characterized by their corrosion resistance, high strength and ductility, and high chromium content( Cr >11%).

• Stainless as a film of chromium oxide protects the metal from corrosion.

• It resist oxidization and maintain mechanical integrity at high temperature (1000°C).JIS/KS Cr(%) Heat

treatCor. Res.

Magnetic

Application

SUS304 austenite 19 X OO X Automotive exhaust

SUS409 ferrite 11 X O O Chem. proc. equip.

SUS410 martensitic 12.5 O O O Knifes



Posco

• Hot rolled steel, Steel plate, Wire rod, Cold rolled steel, Electric steel, Stainless steel, Galvanized steel, Titanium

Posco http://www.posco.co.kr



Cast Irons ( 주철 )

• Ferrous alloys with 3.0 ~4.5% C• Low melting point relatively easy to cast• Generally brittle

• Cementite decomposes to ferrite + graphiteFe3C 3 Fe () + C (graphite) : slow process



Cast IronsGray iron( 회주철 )• graphite flakes• weak & brittle in tension• stronger in compression• excellent vibrational dampening• wear resistant

Ductile iron( 연주철 )• add Mg and/or Ce• graphite as nodules not flakes• matrix often pearlite – stronger but less

ductile



Cast IronsWhite iron( 백주철 )• < 1 wt% Si• pearlite + cementite• very hard and brittle

Malleable iron( 가단주철 )• heat treat white iron at 800-900ºC• graphite in rosettes• reasonably strong and ductile



Cast Irons

급랭 서랭

가열

가단주철 백주철 회주철 연주철



Nonferrous Alloys ( 비철금속 )

More expensive than ferrous metals.Applications:• aluminium for aircraft bodies • copper wire • titanium for jet-engine turbine blades • tantalum for rocket engines



Nonferrous Alloys( 비철금속 )

NonFerrous Alloys

• Al Alloys-low : 2.7 g/cm3 -Cu, Mg, Si, Mn, Zn additions -solid sol. or precip. strengthened (struct.

aircraft parts & packaging)

• Mg Alloys-very low : 1.7g/cm3 -ignites easily -smartphone

• Refractory metals-high melting T’s -Nb, Mo, W, Ta• Noble metals

-Ag, Au, Pt -oxid./corr. resistant

• Ti Alloys-relatively low : 4.5 g/cm3

vs 7.9 for steel -reactive at high T’s -space applic.

• Cu AlloysBrass: Zn is subst. impurity (costume jewelry, coins, corrosion resistant)Bronze : Sn, Al, Si, Ni are subst. impurities (bushings, landing gear)Cu-Be: precip. hardened for strength



Copper alloys

• Copper alloys( 구리합금 ) have electrical and mechanical properties, corrosion resistance, thermal conductivity and wear resistance.

• Applications are electronic components, springs and heat exchangers.

Brass( 황동 ) is an alloy of copper and zinc (Zn 30%). Applications are costume jewelry, coins, corrosion resistant.

Bronze( 청동 ) is an alloy of copper and tin (Sn 10% , Al, Si, Ni). Applications are bushings, landing gear.



Aluminium alloys

Factors for selecting Aluminum (Al) alloys are:•High strength to weight ratio ( 2.7 g/cm3) •Resistance to corrosion•High thermal and electrical conductivity•Ease of machinability•Non-magneticEx) A7075 A6061 A5052



Magnesium alloys

• Magnesium (Mg) is the lightest metal (1.7g/cm3).• It ignites easily.• Typical uses of magnesium alloys are the frame of

electric device like as smart phone.



Nickel alloys

• Nickel (Ni) has strength, toughness, and corrosion resistance to metals.

• Used in stainless steels and nickel-base alloys at chemical and food processing industry (Nikel200).

• Inconel 600 (Cr 15% Fr8%) alloys are used for high temperature applications, such as jet-engine components and rockets.



Superalloys

• Superalloys ( 초합금 ) are high-temperature alloys use in jet engines and gas turbines.

Ex) IN-100 -102, Inconel 625 718, MAR-M 200 432 …



Titanium alloys• Titanium (Ti) is expensive, has high strength-to-weight

ratio and corrosion resistance. Relatively low density 4.5 g/cm3.

• Used as components for aircrafts, jet-engines, racing-cars and medical equipments.

• Ex) Ti-6AI-4V



Refractory metals

• Refractory metals ( 고용융점 금속 ) have a high melting point and retain their strength at elevated temperatures.

• Applications are electronics, nuclear power and chemical industries.

• Molybdenum, columbium, tungsten, and tantalum (Nb, Mo, W, Ta) are referred to as refractory metal.



Other nonferrous metals

1. Beryllium (Be)2. Zirconium (Zr)3. Low-melting-point ( 저 용융점 ) metals:

- Lead (Pb, 납 )- Zinc (Zn, 아연 )- Tin (Sn, 주석 )

4. Precious metals ( 귀금속 ): - Gold (Ag, 금 )- Silver (Au, 은 )- Platinum (Pt, 백금 )



Special metals and alloys

1. Shape-memory alloys2. Amorphous alloys3. Nanomaterials4. Metal foams



Korea Zink ( 고려아연 )

• Zinc (Zn) : Galvanized steel plate(pipe, wire), color steel plate, automobile part, machine/electronic part, anti-corrosion paint

• Lead (Pb) : Automobile and industrial battery, electric wire coating, radiation shielder

• Copper, God, Silver, Indium, nickel, bismuth, antimony trioxide, palladium, platinum, cadmium, gallium, germanium, tellurium, cobalt



Poongsan ( 풍산 )

• Copper (Cu) : sheet & strips, tubes, rods, coin blanks, semiconductor leadframe

Metal Alloys ( 금속 합금 )

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