Brian:
If you search for carbide SS blades becomes hopeless:
Try http://www.mikesworkshop.com/ home of the Flying Dutchman blades, which
IMHO are the best.
Mike's FD Polar blades just might come close to your needs, as they are very
hard steel.
Stick to larger sizes like a #7 or #9. But be aware this is not for thin
stock as teeth per inch is low count.
Slow you saw's strokes per minute down to under 1000 spm. and slow your feed
rate down to match the spm.
Mike is good people. Email him from his web page with your question, and my
suggestion for Polar #9 blades.
Mike just might know of a source where he could supply you with a better
product to try.
Heat is the worst enemy of your cutting / blade life. Heat is caused by
chips not being removed and causing friction. Don't trust just to your dust
collection, get some air blowing / sucking on top also. You must remove the
chips.
Please don't forget, that any sideways pressure on the blade will shorten
the blade life significantly. Always cut such that so that at rest, the
blade does not seek to move forward, or cut sideways.