to muddy the waters
I used to install and maintain induction furnaces from 56 pound to 11 tons
the 11 ton ones were 1.5 mega watt units
we used to melt ferrous metals in all of them
but what I do know is that the smallest size one was run at a much higher frequency that the big ones these ran at 50 hz but the smaller one ran at 200 hz this was done because as the size goes down the % goes with it hence the inc. in HZ
all of these furnaces were parallel resonant circuits with water cooled coils , I cannot remember the volts for the small ones but the big ones had a coils voltage of 1kv, the operators just adjusted the cap bank for unity PF
at a small scale you would need to go to a HF source , heating is one thing melting is a different ball game , its the eddy currents that do the work nothing to do with the ferrous properties as iron/steel is none magnetic over a certain temp ( infact you use that property to establish the correct temp for hardening the metal when the magnet will not stick its hot enough )
Stuart