If you're expecting melting, you'd need hundreds, if not thousands of degrees of heat to actually matter to bodies converted to pure metal. And that would have irradiated all around you when you made it, burning your soft flesh very much easier than it could hardened steel.
That aside, energy is energy. It's controllable, raw force. You may be absorbing thick amounts of raw force to use, but when trying to shove it straight into a large mass made for defensive measures such as the metallic form these things carry, you might as well be trying to shoot a pistol into the ground. You may make a scratch with what strength you got, but you're not strong enough to actually matter to it. And that's if the force is focused at one point. Seeing as you scattered the energy to spread it out, you weakened what little damage you could have done.
Reason: I created Harper and Breeder to fight the teachers, so I had designed them with higher levels of power than what the students might be able to contend with.