thermal knife power supply (part 2)
0.6V at 20A indicates a resistance of 0.03&ohm;. P=V2R, so for 60W you need to supply 1.34V (at 45A). 

Obviously your transformer is not suitable, however you might be able to modify it to get lower voltage at higher current. Some transformers have a gap between the windings and the core, which you may be able to thread a few turns of thick wire (at least 14AWG) through. If you can get enough turns to produce 1.34V then it should provide the required current. 

If your transformer has no room for extra wire, but has separate bobbins for primary and secondary windings, you could cut off the secondary winding and replace it with your own thicker wire. 

Here's an example:-

How to: High current Microwave oven Transformer

    

To fine tune the power you cauld either tap into several positions on the output winding, or add a variable length of cable to drop the voltage. You only need about 0.012&ohm; to drop 0.4V, which would cut power to the knife by half.