Does anyone know the value for constant in Chvorinov formula, for different materials, for example ductile iron?
Based on Chvorinov's formula, Caine developed equation which is normally used for risering design. Please see the following book for different formulae.
For ductile iron in CO2 moulds, the following equation may be used.
X = 39.44 / (27.78 - Y)
Book Manufacturing Technology, Vol. 1 Foundry, Forming and Welding
Excuse me Nageswara, in the formula, what is X, Y, and the units of each one, please?.
Thanks you.
Chvorinov's formula is an expansion of one directional heat flow to three dimensions. Because of the assumptions made, the value of the exponent changes and the constant becomes mostly empirical. We showed that the solidification time can be written as V^(2/3) k^(4/3) where V and k are volume and shape factor, respectively. You can find the publications here:
https://www.researchgate.net/publication/235909077_The_effect_of_casting_shape_and_size_on_solidification_time_a_new_approach
https://www.researchgate.net/publication/259623403_Statistical_investigation_of_the_effects_of_the_shape_size_and_superheat_on_solidification_times_of_castings
Article The effect of casting shape and size on solidification time:...
Article Statistical investigation of the effects of the shape, size ...
The Chvorinov rule calculates the solidification time of a casting. The dimensions of the casting are charcterised by the volume over surface ratio. The solidification time is proportional to the square of this ratio. The proportionality constant is dependent of the thermophysical properties of the mould material. see eg John Campbell's book Castings (Butterworth)
it is important theory in solidification and you can calculate the solidification time for the case and also the riser and so you can use it to calculate the riser dimensions and number need to have a sound cast
Daniel
X = (Surface area / Volume) of casting/(Surface area/Volume) of riser
Y = Riser volume / casting volume
This equation is used to size the riser for a given casting.
If possible, I need a table with Chvorinov constant values for differents materials.
Thanks you.
Daniel, do not use Chvorinov's rule, it is not accurate. The exponent changes with shapes of the casting.
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