Casting Materials Prof. Juhani Orkas
Overview Iron based Grey iron Nodular iron White iron Cast steel Nonferrous cast materials Aluminium alloy Magnesium alloy Titanium alloy Copper alloy Nickel-base alloy
Iron-carbon diagram Cast iron C > 2,06 % Grey cast iron Stable system Fe-C Iron-graphite Si, Ti, Al White cast iron Metastable system Fe-Fe 3 C Iron-cementite Mn, Cr, Mo
http://www.hoffmann-group.com/download/de/zhb_2006_2007/teil/web_pdf/053-093.pdf Classification of iron based materials Iron based materials Grey cast iron White cast iron Cast steel Lamellar graphite iron Vermicular graphite iron Spheroidal graphite iron Alloyed cast iron Malleable iron Chilled iron GS GJL GJV GJS ADI Whiteheart melleable iron Blackheart malleable iron GJN GJMW GJMB
Cast iron Carbon cut out as Graphite Grey color at the fracture surface Silicon Graphite stabilizing Compressive strength higher than tensile strength (~2:1) No bond between Iron and Carbon Good machinability Carbon interrupts the metal micro-structure Carbon lubricates the cutting tools Designation system: GJ(Symbol) - R m
Wikipedia: Datei:GGV-GGG.jpg Cast iron - Overview Lamellar graphite iron (GJL) Pressure and wear-resistant Corrosion-resistant Good damping characteristics Low tensile strength and elongation at fracture Low costs Vermicular graphite iron (GJV) Between GJL and GJS Low thermal expansion Spheroidal graphite iron (GJS) Ductile High tensile strength and elongation at fracture
http://mciron.mw.tu-dresden.de/lut/vorlesung/script_ft1/ft1%20vl%20%202%20gu%c3%9ftechnik.pdf Cast iron - Overview Un-etched photomicrograph SEM image
Lamellar graphite iron GJL http:// http://www.htw-aalen.de/gta/de/eisenguss/eisenguss.htm Ferritic-pearlitic structure R m 400 MPa Poor toughness Good compressive strength Cooling conditions affects microstructure Tensile strength depends on wall-thickness Higher strength in thin walls Very good damping capacity (Vibration) GJL : GJS : Steel 1 : 1,8 : 4,3 Notch-sensitive High tension gradient at graphite flakes Good friction properties Very good pouring properties EN GJL-250
Surface hardening http://www.kug.bdguss.de/fileadmin/content/publikationen-normen-richtlinien/buecher/gjl.pdf Thermophysical hardening Martensitic hardening 55 60 HRC Ledeburitic hardening Better wear resistance Thermochemical hardening
Lamellar graphite iron GJL www.claasguss.de/pdf/psst_ant_5_2007.pdf Bed for machine tools EN GJL-250 /-300 Up to 12,8 m Gearbox for a printing machine EN GJL-250
Spheroidal graphite iron GJS http:// http://www.htw-aalen.de/gta/de/eisenguss/eisenguss.htm Add magnesium or cerium Spheriodal graphite Ferritic-pearlitic structure R m 800 MPa Moderate toughness Less Notch-sensitive than GJL Average tension gradient at graphite spheres Moderate damping capacity For mechanical stresses parts EN GJS-400 EN GJS-700
Spheroidal graphite iron GJS http://www.claasguss.de/html_e/pdf/thbl2_engl.pdf High C- and Si-level Low strength and Brinell hardness High elongation at fracture
Spheroidal graphite iron GJS http://www.fwh.de/produkte.html Cylinder block for marine diesel engine EN GJS-400-18U 9 x 2.84 x 3.35 m 81 450 kg Rotor hub (1.5MW) EN GJS-400-18U-LT 3.128 x 2.7 x 2.1 m 8 400 kg
http://schonlau-werke.de/en/manufacturing-products/materials/austempered-ductile-iron http://www.claasguss.de/html_e/html/produkt_02_05.html Austempered ductile iron ADI Multi-step heat treatment of GJS Bainitic-similar structure Acicular ferrite and carbon-enriched austenite (without carbide precipitation!) R m 1400 MPa Steely characteristics Very good wear resistance Even greater with added hard carbides (CADI) Lower specific weigh than steel (~10%) Comparable mechanical properties ADI 800/ EN GJS-800-8
Austempered ductile iron ADI http://www.ductile.org/didata/section4/4intro.htm Relative weight Relative costs
Multi-step heat treatment ADI http://www.claasguss.de/html_e/pdf/thbl8_engl.pdf Austenizing Heating above AC1 temperature (840-950 C) Completely austenitic microstructure Quenching Avoid formation of perlite Austempering Salt / oil bath or oven (250 450 C) Isothermal transformation Ferrite needles and austenite (Ausferrite) Too short holding metastable residual austenite Too long holding: real bainite (ferrite with carbide precipitation)
Multi-step heat treatment ADI http://www.msm.cam.ac.uk/phase-trans/2001/adi/adimore.html http://www.claasguss.de/pdf/08_th_adi.pdf Austenitised at 950 C, Austenitised at 950 C, austempered at 400 C for 53 min austempered at 250 C for 50 min low strength at higher elongation high strength with high hardness at fracture and high wear resistance but imited ductility
Austempered ductile iron ADI http://www.htw-aalen.de/gta/de/eisenguss/eis http://www.ductile.org/didata/section4/4intro.htm enguss.htm ADI crankshaft TVR sportscar ADI gears Hymi Kymmene Engineering, Finland
Vermicular graphite iron GJV http://www.claasguss.de/html_e/pdf/thbl12_engl.pdf Deliberately insufficent treatment to build Spheriodal graphite Three-dimensional worms Properties between GJL and GJS Ferritic-pearlitic structure R m 600 MPa Especial suitable for thermal and mechanical stressed parts EN GJV-400
Vermicular graphite iron GJV http://www.claasguss.de/html_e/pdf/thbl12_engl.pdf Advantages to GJL Better tensile strength and elongation at fracture Higher fracture toughness Properties are less dependent on wall thickness Advantages to GJS Lower coefficient of thermal expansion Higher heat conductivity Lower modulus of elasticity Better thermoshock resistance and lower tendency to distortion Better damping capacity Better pouring properties
Vermicular graphite iron GJV http://www.claasguss.de/html_e/pdf/thbl12_engl.pdf http://trucks.autoreview.ru/new_site/trucks/archives/2004/n03/4_man/1.htm Audi V12 TDI crankcase EN GJV-450 500PS / 1 000 Nm More rigid and fatigue-resistant Thinner walls and less weigh MAN TG-A cylinder block EN GJV-450 430 PS
http://www.edelstahlwerke-schmees.de/content/picture/upload/image/werkstoffe/wk8_big.jpg Austenitic cast iron materials GJSA > 20% nickel (Ni-Resist) Austenitic structure Extremely corrosion resistant Sea water & alkaline media High heat resistance Adjustable thermal coefficient of expansion Nickel contend Max at ~20% Min at ~35% Laminar and spheroidal graphite possible Non-magnetizable Good running properties EN GJSA-XNiCr20-2
Austenitic cast iron materials GJSA x Cylinder block for LNG 35% Nickel Huge temperature difference between suction and pressure valve Housing of turbocharger K16 BorgWarner Temperatures around 1000 C
White cast iron Google Books: Gefüge Der Gusseisenlegierungen White cast iron Malleable iron Chilled iron Whiteheart melleable iron Blackheart malleable iron GJN GJMW GJMB
Google Books: Gefüge Der Gusseisenlegierungen White cast iron x Carbide stabilizing elements (Mn, S) Graphite-free solidified Fe 3 C Perlit and ledeburit (hypoeutectic) White color at the fracture surface Hard and brittle Less applications Intermediate product in steel production Heat treatment for malleable iron Cementite decompose to temper carbon (equiaxed nodular graphite) Temper carbon interrupts matrix less then carbon in grey iron Better mechanical properties
http://www.hitzbleck.de/englisch/products.htm Whiteheart malleable cast iron GJMW Malleablizing in oxygen containing atmosphere 60 to 120 h at 1000 C Cementite decompose to Fe and C Fe 3 C 3Fe + C Carbon diffuses outwards Converts in the surface to CO and CO 2 C + O 2 CO 2 Decarburization depends on wallthickness Max. 8mm for complete decarburization Residual carbon as Temper carbon
Functionally graded http://www.hitzbleck.de/gradienten.htm Surface Graphite-free, ferritic structrue High ductility Excellent machinability Suitability for welding Suitability for surface treatment Transition Ferritic-perlitic structrue with temper carbon Core Perlitic structure with temper carbon High stiffness
Weldability http://www.hitzbleck.de/ Residual carbon content < 0.3% at weld area No preparation and postprocessing All welding methods No hardness increaseing Suitable for connecting complex casted parts with semi-finished products
Cold forming http://www.hitzbleck.de/
http://de.wikipedia.org/wiki/temperguss http://www.msm.cam.ac.uk/phase-trans/2001/adi/cast.iron.html Blackheart malleable cast iron GJMB Malleablizing in neutral atmosphere Inert gas 1 st level of graphitization approx. 20 h at 940-960 C Cementite decompose to Fe and C Fe 3 C 3Fe + C Temper carbon in a austenitic matrix 2 nd level of graphitization Cooling to 700-800 C Eutectoid transformation γ α + C Carbon from austenite diffused to existing temper carbon Cooling rate affects the final matrix
Matrix of GJMB http://de.wikipedia.org/wiki/temperguss Ferritic structure Slow cooling to 700 800 C Stable eutectoid transformation Temper carbon evenly distributed Perlitic structure Fast cooling Metastable solidification to perlite Martensitic structure Very fast cooling Suppressed diffusion Martensite Mixed structure
Chilled iron GJN x http://www.metallographie-ausbildung.de/wasist.html High S and Mn or rapid cooling Surface White iron Graphite-free cementite Ledeburiteutecticum Up to 20 mm Extreme hard and wear resistant Core Grey iron Perlitic structure with laminar graphite
Chilled iron GJN http://www.walzenirle.com/de/walzen/papierindustrie/produktspektrum/standardkalanderwalzen/standard-kalanderwalzen.html http://www.weartechnology.com.my/brochures/castings.pdf Extrealmy wear-resistant Rolls Milling disks Ore crusher Crawler elements Armor plates
Cast steel GS http://www.maschinenbau-wissen.de/skript/werkstofftechnik/stahl-eisen/31-stahlguss Advantages Mechanical properties of steel together with the castability Malleable Wide range of materials Adjusable strengt properties Heat treatment necessary Disadvantages Higher melting point > 1400 C High demands on technology Bad mould-filling capacity More viscouse than cast iron hypoeutectic High shrinkage ~2% Castings without heat treatment unusable Brittle Coarse grain Dendritic
Cast steel GS http://www.voestalpine.com/giesserei_traisen/de/products/foundry_products.html Pelton wheel High strengt Shunting switch G-X120Mn12
http://www.hoffmann-group.com/download/de/zhb_2006_2007/teil/web_pdf/053-093.pdf Classification of nonferrous cast materials Nonferrous cast materials Light metal cast Heavy metal cast Precious metal cast Aluminum casting Magnesium casting Titanium casting Copper casting Pewter casting Lead casting Zinc casting Gold casting Silver casting Platinum casting G-Al G-Mg G-Ti G-Cu G-Sn G-Pb G-Zn G-Au G-Ag G-Pt
http://www.openpr.de/news/278394/aluminiumguss-verdraengt-herkoemmlichen-grau-und-stahlguss.html Aluminum alloy Suitable for complex thin-walled parts High dimensional accuracy Low weight with high rigidity Good strength-weight ratio Smooth surfaces and edges Good machinability High thermal conductivity Good electrical conductivity Corrosion and weathering resistance Several surface treatments possible
http://www.eaa.net/eaa/education/talat/lectures/1501.pdf Aluminum alloy designation system
Aluminum alloy http://www.eaa.net/eaa/education/talat/lectures/1501.pdf
Aluminum alloy xxx Casting alloys Most common 4xxx For die casting 4xxx 5xxx 7xxx For gravity die casting 2xxx 4xxx 5xxx 7xxx
Aluminum alloy http://www.hoffmann-group.com/download/de/zhb_2006_2007/teil/web_pdf/053-093.pdf http://www.msm.cam.ac.uk/phase-trans/abstracts/m7-8.html Al Si (4xxx) Near eutectic (12% Si) Low melting point (576 C) Good fluidity Less shrinkage High strength Hypereutectoid (up to 25% Si) Used as piston alloy Worse fluidity Primary solidification of Si Higher wear resistance due to Si crystals Lower coefficient of expansion
http://mciron.mw.tu-dresden.de/lut/vorlesung/script_ft1/ft1%20vl%20%202%20gu%c3%9ftechnik.pdf Aluminum alloy Hypoeutectic Eutectic Hypereutectic
http://aluminium.matter.org.uk/content/html/eng/default.asp?catid=214&pageid=2144417057 Aluminum alloy - Treatments F Without treatment O Solution annealed Dead soft, low strength T Heat treated H Strain hardened i.e. for non age hardening alloys
Precipitation hardening http://www.hsc.csu.edu.au/engineering_studies/aero_eng/2580/aluminium_alloys.html http://www.azom.com/details.asp?articleid=2540 Before Treatment Precipitates along grain boundaries Solution Heat Treatment Heat above solvus temperature Dissolve any precipitates Alloying elements in solid solution Quench No time to diffuse Supersaturated solid solution
Precipitation hardening http://www.hsc.csu.edu.au/engineering_studies/aero_eng/2580/aluminium_alloys.html http://www.azom.com/details.asp?articleid=2540 Hardening Below solvus temperature Alloying elements diffuses to coherent precipitate clusters Increases strength and hardness Natural ageing Room temperatur Stops after several hours Artificial ageing Precipitation heat treatment Higher hardness then with natural ageing
Precipitation hardening http://www.hsc.csu.edu.au/engineering_studies/aero_eng/2580/aluminium_alloys.html Overageing First partially coherent precipitations Later incoherent precipitations Reduced tensile strength Remember for designing parts with a higher operation temperature! AlCu 2014-T6
Precipitation hardening http://www.alumag.de/downloads/innovation%20durch%20aluminiumguss,%20ksm.pdf Differential housing from KSM Castings GmbH Cast-on rivets Connect housing cover with housing bell Clinch rivets directly after quench Artificial ageing for final strength and hardness
Aluminum alloy http://www.alumag.de/downloads/innovation%20durch%20aluminiumguss,%20ksm.pdf Daimler valve body AlSi9Cu3 Wall-thickness: 2-6mm Drafts: 1 (valve core 5 ) BMW integral cross member EN AC - AlMg5Si2Mn Weldable without pre-treatment
http://www.dynacast.com/casting/magnesium/ Magnesium alloy Lightest of all structural metals ~ 1800 kg/m 3 Excellent strength-weight ratio Hexagonal lattice High strength High electrical and thermal conductivity Without Al and Zn Brittle Notch-sensitive Excellent machinability Good damping coefficient Better vibration reduction than Al or GJx
Roos, Maile: Werkstoffkunde für Ingenieure Magnesium alloy Al and Zn Avoid problems with brittleness and notch-sensitivity Mg Increases corrosion resistance Ce and Th Increases high temperature strength Zr Grain refinement Increases strength and formability
http://www.arcraftplasma.com/welding/weldingdata/metalstd.htm Magnesium alloy designation system Two letters for the major alloying elements Two digits for the approximate percentage of the elements May an additional letter for the different alloy modifications Example: AZ91C Approx. 9% Al; approx. 1% Zn; the 3th modification
xx Titanium alloy Very high tensile strength and toughness even at extreme temperatures Light weight Properties depending on phase α phase α+β phase β phase Extreme corrosion resistance Very dense TiO2 layer Biocompatibility Expensive
Titanium alloy http://www.substech.com/dokuwiki/doku.php?id=classification_of_titanium_alloys α phase Good fracture toughness Good creep resistance Not heat-treatable α+β phase High mechanical strength Up to 1000 MPa Heat-treatable Ti6Al4V (50% of world usage) β phase Heat-treatable Very high strength up to 1400 MPa
xx Copper alloy Properties Corrosion resistance Good bearing qualities Attractive appearance Bronze CuSn Brass CuZn Red brass (gunmetal) CuZnSn Aluminium bronze CuAl CuSn11 (50:1) CuAl20 (500:1)
Bronze (CuSn) http://www.kupfer-institut.de/front_frame/frameset.php3?client=1&lang=1&idcat=33&parent=14 Up to 20% Sn 9 12% for casting alloys Nonmagnetic High thermal and electrical conductivity High corrosion resistance Seawater resistance Good wear resistance Good damping coefficient Red brass (CuZnSn) Cheaper due to cheap Zn Similar properties
Brass (CuZn) http://www.kupfer-institut.de/front_frame/pdf/i05_0307.pdf http://www.otto-fuchs.com 5 to 45 % Zn Tensile strength up to 750 MPa No cryogenic embrittlement Good corrosion resistance Depends on alloying element Antimicrobial Used at public places Specialbrass CuZn + other element Impeller for a pump CuZn37Mn3Al2PbSi Multi Cone Synchro System Depends on the application
http://www.kupfer-institut.de/front_frame/frameset.php3?client=1&lang=1&idcat=33&parent=14 Aluminium bronze (CuAl) 9 14% Al High corrosion resistance Seawater resistance Good wear resistance Good cavitation resistance Applications Ship propeller Sliding elements Bearings Chemical industries Gear wheels World largest ship propeller (MMG) CuAl9Ni6Fe5Ma Container ship with 120,000 PS 9,6 m; 131 t
Nickel-base alloy http://www.kupfer-institut.de/front_frame/frameset.php3?client=1&lang=1&idcat=33&parent=14 Pure nickel Ductile and tough face-centered cube crystal structure up to its melting point High resistance against Corrosion environments High temperatures ( 1100 C) High stresses Base for developing specialized alloys Intermetallic phases very high strength alloys low- and high-temperature