university of cambridge department of materials science and metallurgy modelling the microstructure...
Post on 19-Dec-2015
219 views
TRANSCRIPT
![Page 1: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/1.jpg)
University of CambridgeDepartment of Materials Science and Metallurgy
Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast Iron
By
Miguel Angel Yescas-Gonzalez
![Page 2: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/2.jpg)
CHEMICAL COMPOSITION OF CAST IRON:Fe C Si Mn P S Mg
val. 3.5 2.5 0.25 0.038 0.015 0.05
Grey cast iron
Ductile cast ironAddition of cerium or magnesium to inducenodularisation of graphite
Only in Ductile iron
No addition of Mg or Ce
Tensile strength: 150-400 MPa
Tensile strength: 350-800 MPa
Elongation: 3-20 %
Elongation: 0 %
![Page 3: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/3.jpg)
Microstructure of Ductile irons
![Page 4: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/4.jpg)
1. Austenitising between 850 and 950 Ctypically for 60 min.
2. Quenching into a salt or oil bath at a temperature in the range 450 - 250 Cusually between 0.5 and 3 hours
3. Cooling to a room temperature
Austempered ductile cast iron (ADI)
A further improvement of ductile cast iron is obtained with anisothermal heat treatment named austempering
![Page 5: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/5.jpg)
Mechanical properties
STRENGTH : equal to or greater than steel
ELONGATION : maintain as cast elongation while double the strength of quenched and tempered ductile iron
TOUGHNESS : better than ductile iron and equal to or better than cast or forged steel
FATIGUE STRENGTH : equal to or better than forged steel.
DAMPING : 5 times greater than steel.
![Page 6: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/6.jpg)
R. Elliott, 1988
![Page 7: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/7.jpg)
ADI has excellent castability, it is possible to obtain near-net shape castings even of ADI has excellent castability, it is possible to obtain near-net shape castings even of high complex parts. high complex parts.
ADI is cheaper than steel forgingsADI is cheaper than steel forgings
ADI has a weight saving of 10% ADI has a weight saving of 10%
Economical advantages and applications
Gears Automotive industry
![Page 8: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/8.jpg)
Processing windowThe bainitic transformation in ductile iron can be described as two stage reaction:
Sage I: Austenite decomposition to bainitic ferrite and carbon enriched austenite
g +Sage II: Further austenite decomposition to ferrite and carbide
g + Carbide
gra
r a
![Page 9: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/9.jpg)
Closed processing window
![Page 10: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/10.jpg)
Microstructure of ADI
Bainite
Retained austenite
Martensite
Carbide
Pearlite
![Page 11: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/11.jpg)
Element Cell boundary Close to graphite Mn 1.73 0.40 Si 1.75 2.45 Mo 0.60 0.07
Element Cell boundary Close to graphite Mn 0.81 0.57 Si 2.31 2.49 Mo 0.16 0.12
Fe-3.5C-2.5Si-0.55Mn-0.15Mo
![Page 12: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/12.jpg)
homogenised at 1000 C for 3 days
Austempered at 350 C for 64 min
o
![Page 13: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/13.jpg)
![Page 14: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/14.jpg)
![Page 15: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/15.jpg)
Variables for modelling include:
C, Mn, Si, Mo, Ni, Cu,
Austenitising temperature and time
Austempering temperature and time
Vg= a + b (%C) + c (%Mn)
Vg= a + b (%C) + c(%Mn) + d (%C x %Mn)
Vg = sin (%C) + tanh (%Mn)
![Page 16: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/16.jpg)
V
TA Mn
INPUT
HIDDEN
OUTPUT
C
g
sum
C x WMn x W
cMn
![Page 17: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/17.jpg)
Modelling with neural networks
a) three different hyperbolic tangents functionsb) combination of two hyperbolic tangents
Hyperbolic tangents
![Page 18: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/18.jpg)
Modelling with neural networks
Microstructural modelfor volume fraction of
retained austenite(V )
NEURAL NETWORKS
DATABASE(Experimental data)
g Input variables
Output or target
h = tanh (S w x + )qijj ji i
![Page 19: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/19.jpg)
![Page 20: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/20.jpg)
Error bars
![Page 21: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/21.jpg)
![Page 22: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/22.jpg)
![Page 23: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/23.jpg)
![Page 24: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/24.jpg)
![Page 25: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/25.jpg)
![Page 26: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/26.jpg)
![Page 27: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/27.jpg)
![Page 28: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/28.jpg)
Physical Model for Retained Austenite
![Page 29: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/29.jpg)
![Page 30: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/30.jpg)
![Page 31: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/31.jpg)
![Page 32: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/32.jpg)
![Page 33: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/33.jpg)
Babu etal. 1993
![Page 34: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/34.jpg)
![Page 35: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/35.jpg)
![Page 36: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/36.jpg)
![Page 37: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/37.jpg)
![Page 38: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/38.jpg)
40 mm
![Page 39: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/39.jpg)
![Page 40: University of Cambridge Department of Materials Science and Metallurgy Modelling The Microstructure and Mechanical Properties of Austempered Ductile Cast](https://reader036.vdocument.in/reader036/viewer/2022062421/56649d385503460f94a10e42/html5/thumbnails/40.jpg)