Qn r*
S
scr Sc
tb te
Casting cooling rates of ductile iron, respectively at graphite eutectic equilibrium temperature Ts
Critical size of a graphite nucleus Wall thickness of the plate castings
Critical wall thickness below which, chill is formed Carbon saturation
Time at onset of graphite eutectic solidification Time at end of solidification
Tc Ti
tm
Tl Tlγ
Tm Ts
U
Vc W
Z α β
∆H ∆T
∆Tm
∆Tm,n ∆Tsc φ
ε
η λ µ θ σ
σ1 σ2
ξ
Time at maximum undercooling of graphite eutectic Cementite eutectic formation temperature
Initial temperature of cast iron just after pouring into mold
Liquidus temperature of pre-eutectic austenite with maximum composition of carbon
Minimal temperature at onset of eutectic solidification Graphite eutectic equilibrium temperature Eutectic cell growth rate Volume of casting
Wedge angle
Coefficient related to slopes of the solubility lines JE’, E’S’ and BC’ in Fe-C system Latent heat of solidification Degree of undercooling
Maximum undercooling at onset of eutectic solidification for flake graphite cast iron
Maximum undercooling at onset of eutectic solidification for ductile iron
= Ts – Tc
Contraction coefficient of Heat coefficient of metal
Viscosity of the liquid in mushy zone Inter-graphite distance
Growth coefficient of graphite eutectic Wetting angle
Nucleus-melt interfacial energy Substrate-melt interfacial energy Nucleus-substrate interfacial energy Material constant
C, Si and P Content of carbon, silicon & phosphorus in cast iron
Eqn.(16) Eqn. (5)
-
Fig. 2 Fig. 2 Fig. 2
Table 2 -
Liquidus temperature at onset of pre-eutectic austenite solidification Table 2 Table 2 Table 2 -
Width of total chill of wedge (ASTM A367-55T Standard) Parameter
- - -
Eqn. (21) -
Table 2 - -
Eqn. (24) Eqn. (25)
Eqn. (32) -
Eqn. (18) Eqn. (34)
Table 2 Fig. 3 Fig. 3 Fig. 3 Fig. 3 - -
oC/s cm cm cm -
s s s
oC oC oC
oC oC oC
cm/s cm3 cm -
degree oC-1
J/cm3 oC
oC
oC oC
J/(cm3 o N s/cm2 cm
cm/(so degree J/cm2 J/cm2 J/cm2 cmo
C wt. % C) C2 )
REFERENCES
1. Fraś, E., Górny, M., Lopez, H.F., “Chilling Tendency and Nodule Count in Ductile Cast Iron Part I - Theoretical Background,” AFS Transactions, vol.114, pp. 575-594 (2006).
2. Fraś, E., Górny, M., Lopez, H.F., “Chilling Tendency and Nodule Count in Ductile Cast Iron Part II - Experimental Verification,” AFS Transactions, vol.114, pp. 595-603 (2006).
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3. Fraś, E., Górny, M., Lopez, H.F., “The Transition from Gray to White Iron during Solidification, Part I – Theoretical Background,” Metallurgical and Materials Transactions A, vol. 36A, pp. 3075-3082 (2005).
4. Fraś, E., Górny, M., Lopez, H.F., “Eutectic Cell Count, Chilling Tendency and Chill in Flake Graphite Iron, Part II-Experimental,” AFS Transactions, vol. 115, pp. 453- 465 (2007).
5. Nicholas, K.E., “Inoculation and Casting Expansion,” British Cast Iron Research Association Journal, no.1, pp. 103-116 (1961).
International Journal of Metalcasting/Summer 10
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