If I know my mass, Cp, Mp and Ambient I can calculate the number joules required to make the mass of metal reach the Mp. How do I figure time?

Joules are convertable to watthour, I know the wattage of the heater, so then do I just divide the two?

IE: 20Kg, 0.167 J/gm*C, 138C, ambient 20C

Res: 394120J

Converting gives: 109.5 watthour

The heat required to get over the heat of fusion (Hf) is given by:

mass*Hf = 982000J

and conversion gives: 272.78 watthour

So the total required heat to melt 20kg of metal is 382.28 W*hrs

Do I just divide by the wattage? (I know that this is assuming 100% effective transfer of heat, but some assumption is always necessary.)

So a 1000watt heater will take 0.3823hrs? My empirical evidence doesn't support this result.

Even at 20% transfer I get 1.91hrs, still nowhere near the empirical result.

Or is my 1000watt melting pot just really that bad at transfering the heat to the metal?

thanks

Nick

I love materials science!