Upload
yogeshmangulkar
View
220
Download
0
Embed Size (px)
Citation preview
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
1/28
Grey Iron Cylinder InoculantFloat
Joe Licavoli Aaron Lueker
Dan SeguinPaul NelsonTerri Mullen
Andrew Zeagler
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
2/28
Process Grey Iron was cast into many
different cylindrical moldswith varying height; 6,12, and20in
Inoculant was added to themelt to initiate nucleationsites for graphite flakes toform in the solid
The uniformity of flakesaffects the mechanicalproperties of the material
Type D/E Flakes 20 m Scale Bar
Type A/B Flakes 20 m Scale Bar
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
3/28
Initial Defective Iron Sample
The hollow areainside of the solidifiediron sample is where
the Ferro-Silicateinoculant coagulated,leaving it un-reactedwith the iron.
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
4/28
Considerations for the Grey IronCasting Process
Solidification - The cylinder may take too long tosolidify, giving the inoculant the opportunity tofloat
Flotation - The inoculant may flow almostcompletely to the surface before reacting withthe melt
Dissolution - The radius of the inoculant affectsits flotation. Since dissolution affects radius,dissolution may, in turn, affect flotation
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
5/28
Our Groups Problems to solve
Grey Iron Cylinderproblems
Solidification Flotation Dissolution
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
6/28
Solidification
Chvorinovs rule used to determinesolidification time.
Solidification from top determined usingNewtons Law of cooling. Inconsistencies in calculation with reality. Did not account heat flow from sides through
top.
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
7/28
Solidification from Mold Walls
Calculate energy conducted away from themetal to the mold during solidification
Excess energy had two sources From the phase transformation From superheating
This energy had to be conducted away fromthe metal through mold surfaces
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
8/28
Solidification from the Mold Wall
Chvorinovs rule yields the following equationfor time through Fouriers Law of Conduction:
Time comes out to be 8.9 minutes
t s T p M Q t T p 2
T m T o 2
22 A
2 M2
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
9/28
Effect of Pour Temperature
1400 1600 1800520
530
540
ts T p
T
Notice: Not very temperature dependent
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
10/28
Solidification from Top
Heat dissipated by convection through top of mold Modeled using Newtons Law of Cooling
Heat flux found, multiplied by solidification time and
energy liberated to find depth of solidification as afunction of pour temperature
D sol T p qV m
C Metal T p T m A m1
H f Metal t im
D sol 1773K ( ) .529
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
11/28
Inconsistencies
The calculated solidification distance fromthe top was inconsistent with actual results 1.5- 2.5 in reality
Rough estimate from casting
Did not account for heat flow from sides
through top Limited models for heat transfer coefficient in
calculating heat flux
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
12/28
Magmasoft Simulations Modeled solidification to
understand where inoculantswould have the most time to float
Limitations of the universitiesversion of Magmasoft did not
allow for the modeling of the Ironcontaining inoculant particles
Knowing the temperature andgeometries of the un-solidifiedsections as time passes could
allow for a more accuratecalculation of final inoculantdistribution
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
13/28
Cooling Rate Control of Flake Spacing
Flake spacing is controlled bycooling rate
Since the cylinder has a constant
cooling rate, there is uniform flakespacing throughout the cylinder
This would be a good medium toattempt an experiment todetermine the relationship ofinoculant mixing time vs. flakespacing (i.e. fade)
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
14/28
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
15/28
Simulated Inoculant Mixing
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
16/28
Flotation
The inoculant is mixed in with the liquidgrey iron as it is poured into the transfercrucible
From here it is poured into the desiredmold
As the mold solidifies, the particles ofinoculant begin to float because they areless dense than the grey iron
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
17/28
Flotation contd.
The following calculations were used fromexample 3.3 (Gaskell)
Terminal Velocity-
Also the critical radius for flotation can be
found by
R T p L x 9 v t T p L x
2 Metal Inoculent g.
v t T p L x L xt s T p L
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
18/28
Flotation contd. With this data we can also find the Reynolds
number which will show whether the flow islaminar or turbulent
The Reynolds number will be less than 0.1,exhibiting laminar flow. (This confirms that ourequation for terminal velocity is valid)
R e T p L x 2 R T
p L x
v
t T
p L x
Metal
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
19/28
Flotation cont.
Figure F.1 In this figure the
critical particle
radius is found asthe length of thecylinder isincreased 0 0.1 0.2 0.3 0.4 0.55 10
6
1 10 5
1.510 5
2 10 5
2.510 5
2.325 10 5
9.181 10 6
R T p
L x
0.60.015 L
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
20/28
Flotation Results
Flotation problems -Most of the particles
floated to the
surface withoutreacting with thegrey iron melt
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
21/28
Dissolution
Changes in particle diameter may influenceflotation time
Dissolution equation derived from analogous
heat transfer equations in Gaskell
R t
h D Isi Lsi atSI
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
22/28
Dissolution contd.
Equations derived from Gaskell lead tosolution for mass transfer coefficient h D
hD
2 .4 R e T p L x 0.5
.06R e T p L x 2
3
1
poise
2.410 9
.4
s
.25
2 R T p L x DSi
s
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
23/28
Problems with Result
Calculations do not agree with experiment Unavailable ternary phase diagram forced
approximation from binary phase diagram
Viscosity difference is unknown
hD
2 .4 R e T p L x 0.5
.06R e T p L x 2
3
1
poise
2.410 9
.4
1
1
.25
2 R T p L x DSi
R th D Isi Lsi
atSI
Particle radius ~tenths of mm
R = .2363 mm/s
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
24/28
A More Likely Explanation
Interfacial resistance may account fordifferences
Solidification at inoculant surface mayserve as a barrier to further atomicdiffusion
Conclusion: Better numbers andconsideration of interfacial resistancecould accurately model dissolution.
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
25/28
Conclusions Based on solidification model in conjunction withflotation model, inoculant particles in our
particular application would have ample time tofloat.
The flotation of incoculant did in fact lead to thenumerous pores located on the surface of thecylinder.
Dissolution could be a huge factor in removing
inoculant from the molten iron before it floated,but interfacial considerations need to be taken tounderstand the complete dynamics.
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
26/28
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
27/28
References
Metal Casting Handbook For MY4130 byKarl B. RundmanDavid R. Gaskell An Introduction to
Transport Phenomena in MaterialsEngineering
SAH Free Consulting Firm Bring all yourproblems to me, Ill help ya out. unless
yer a union guy The offices of Lord Chadwick Boyle III & Sir
Chester Fairfax.
8/13/2019 2005 Grey Cast Iron Cylinder Presentation
28/28
Questions
?????