Cooling rate of aluminium casting in water

[frans]

I need to establish the cooling rate of an aluminuim casting weighing say 20 kg starting at 450 deg C immersed into a water bath at 21 deg C. How long to cool down to 50 deg C ?

Maybe someone has experience enough to suggest a reasonable set of assumptions for calculation purposes ? [sig][/sig]

 

[socrates]

Yes; it would appear that assuming the temperature of the water bath is kept constant and the approximate dimensions of your ingots are such that the bootom face lenghth is twice the width and the hight is 4x said width, and the ingots are pure aluminum, then your cooling time; to bring the ingot temperature down from 450 deg C to 50 deg C would be on the order of 347s or 5.78 minutes. In the event that the water were stagnent the amount of heat exhanged to the water would be on the order of 7200 KJ and the time to cool of course would be considerably longer, again assuming that the volume of water is on the order of 20x that of the ingots. In the event that you wish some sort of clarification or my assumptions are simply not what you expected, or I got an answere that you think is totaly wrong feel free to call me at 510 839-4093.
Sincerely,
Dave Sigel, ME