Post on 18-Dec-2015
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
Metal AlloysMetal AlloysManufacturing ProcessesManufacturing Processes
© 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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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.
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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 )
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU6
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%~)
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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.
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
HSLA
High-strength low-alloy steels ( 고강도 저합금강 )• Improved strength-to-weight ratio.• Used in automobile bodies to reduce weight and in
structural plate.
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
Tool & Die steels ( 공구강 금형강 )
• Designed for high strength, impact toughness, and wear resistance at a range of temperatures.
Ex) SKD11 SKD61 NAK80
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU
Posco
• Hot rolled steel, Steel plate, Wire rod, Cold rolled steel, Electric steel, Stainless steel, Galvanized steel, Titanium
Posco http://www.posco.co.kr
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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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU14
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
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© 2013 Su-Jin Kim, GNU© 2013 Su-Jin Kim, GNU15
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