Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU 1 Metal Alloys ( 금속 합금 ) Associate Professor Su-Jin KimSu-Jin Kim School of Mechanical Engineering Gyeongsang National University

Metal Alloys Manufacturing Processes © 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% Copper alloy Aluminum alloy … alloy

Metal Alloys Manufacturing Processes © 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/cm 3 ) as their base metal. Carbon steels (700W/kg) are least expensive of all metals while stainless steels (7,000W/kg) is costly.

Metal Alloys Manufacturing Processes © 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 )

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU Steels Carbon steel ( 탄소강 ) High alloy steel ( 고합급강 ) Low carbon ( 저탄소강 ) C <.25 % Med carbon ( 중탄소강 ) % High carbon ( 고탄소강 ) % PlainHSLA ( 고강도 ) Plain Heat 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 1010 S10C 4310 SNCM S40C 4340 SNCM KD11 304, 409 SUS304

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU 6 Steels AISI/SAE JIS/KSNomenclature( 조성 ) for steels 10xxSxxCPlain Carbon Steels ( 탄소강 ) 40xxSMoxxMo (.2 ~.3%) 41xxSCMxxCr (.80~1.1), Mo (.15~.25) 43xx SNCMxxNi (1.65 ~ 2.0), Cr (.4 ~.9), Mo (.2~.3) where xx is % C x 100 Ex) 1045 S45C – Plain Carbon Steel with 0.45 % C Stainless Steel 304 SUS304 Cr (11%~)

Metal Alloys Manufacturing Processes © 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

Metal Alloys Manufacturing Processes © 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.

Metal Alloys Manufacturing Processes © 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.

Metal Alloys Manufacturing Processes © 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

Metal Alloys Manufacturing Processes © 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/KSCr(%)Heat treat Cor. Res. Mag netic Application SUS304austenite19XOOXAutomotive exhaust SUS409ferrite11XOOChem. proc. equip. SUS410martensitic12.5OOOKnifes

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU Posco Hot rolled steel, Steel plate, Wire rod, Cold rolled steel, Electric steel, Stainless steel, Galvanized steel, Titanium Posco

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU 13 Cast Irons ( 주철 ) Ferrous alloys with 3.0 ~4.5% C Low melting point  relatively easy to cast Generally brittle Cementite decomposes to ferrite + graphite Fe 3 C  3 Fe (  ) + C (graphite) : slow process

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU 14 Cast Irons Gray 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

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU 15 Cast Irons White iron( 백주철 ) < 1 wt% Si pearlite + cementite very hard and brittle Malleable iron( 가단주철 ) heat treat white iron at ºC graphite in rosettes reasonably strong and ductile

Metal Alloys Manufacturing Processes © 2013 Su-Jin Kim, GNU Cast Irons 급랭급랭 서랭 가열 가단주철 백주철 회주철 연주철