We used to cut 6061 all day on a 1/4" 6-tooth blade, at full
speed. The blade lasted as long as it would with wood unless someone
shoved too hard on the metal and stalled the saw, bending and derailing
the blade and cracking it.
I also used to cut thinner 4130 steel sheet on a same sort of
machine, using a 1/2" hacksaw band with 18 tpi, again at full speed.
The teeth round off immediately and the cut is made using the heat
generated by friction. Pretty slow but beats a hand hacksaw. The
pressure against the work has to be just so to get the best travel
rate.

Dan