How to calculate the power required for the medium frequency induction heating furnace to heat 40 and 6 meters in length ?

How to calculate the power required for the medium frequency induction heating furnace to heat 40 and 6 meters in length ?

According to my example below, set into the respective conditions can be calculated: heating the steel to one kilogram in 60 seconds from 25 to 1250 degrees, assuming the efficiency of the heater is 0.5, the power required is: 0.168 × <1250 - 25 >× 1 ÷ 0.24 ÷ 0.5 ÷ 60 = 23.8kW.