How to select induction heaters for forging or melting work

Though the power factor of our IGBT or MOSFET induction heating machines can be 0.9~0.95, it's hard to calculate the exact power requirement for brazing, jointing, quenching, hardening work, it's often depend on experience.
But there is an empirical formula (experimental formula) for forging or melting work with our induction heaters (MF or RF) to calculate your power requirement as below:

• Power (KW) = Weight (kg) * Temperature (℃) / Time (Second)