the smelt the harder and more durable the crankcase will be from time to time the smelt is checked in a modern foundry a sample of the molten metal is poured into a crucible containing a small measuring sleeve which in a matter of seconds transmits the temperature profile to a computer in the office the smelt has the perfect composition when the sample cools down in a certain way and then heats up again the enormous heat is no longer generated with fire but with electricity the principle is similar to the way an induction cooker