How to calculate the heating time of induction heating furnace?

The workpiece diameter is 150mm and the length is 400mm, and the length of the sensor is 6000mm. It is heated to 1100-1200 degrees. The production cycle is required to be 90s. How is this production cycle derived?

The workpiece diameter is 150mm and the length is 400mm and the mass is 56kg

P=(0.168×1200℃×56kg)/(0.24×0.65×90s)=804KW