Some steel is just harder to cut than others, but to have the best chance, I'd slow the saw down and use some cutting oil to keep things cool. Air hardening steels are havoc on blades once you get too hot and they start hardening while you're cutting. It's kind of like a snowball effect. Once they harden, the blade dulls, and then it starts getting even hotter faster, and you're done.
I don't cut a lot of stainless anymore, but for what I do cut (1095 mostly) I put a few drops of cutting oil on the outside of my blade (not the wheel side, for obvious reasons).
A higher tooth count Might help a little bit as well, though you should be ok with 18TPI for what you're cutting.