Just start out low and slow and use your overides to pick up speed.
10 % at a time till you hit the sweet spot. With a 1/2 dia four flute endmill (carbide)
start at about 1000 RPMs and 8 ipm. Make sure the coolent is on target. Also depth of cut should be 1/4 the dia of the cutter, no more and tool inguagement should be about 55% in a climb cut. Just remember that most types of steel will work harden if you let it get too hot. If the steel starts to change color your pushing it to hard. With alum. the coolent is just taking away the heat so it can be kind of thin. With steel you need more lubracation so you might want to thicken it up a little. Good luck sorry about the spelling.
Be carefull what you wish for, you might get it.