I'd agree with Kong, you should use coolant if at all possible.
HSS partoff blades are "almost useless" when parting off steel. This is because the chip does not get "smooth" until the circumferential speed is above...I dunno..... 300 feet per minute. Since HSS can only stand 100 feet per minute (or less in steel cutting) this presents a bit of a problem.
There are often tool company promotions where they will sell you 10 carbide inserts and give you the blade for free. This might be something to ask about. However, you will have to have your own blade holder, and the typical Armstrong style partoff blade holder might have to be replaced with a new unit designed for carbide insert blades.
Even though carbides should also be flooded for parting, I do use them dry a fair amount of the time in manual machining. You've got to "think positive" and really feed the tool in though. The aim is to make a nice "clockspring chip coil". Stop the cut once in a while, back the tool out and apply some cutting oil to the cut (you'll want to ventilate the fumes). Don't crack your carbide by using little shots of watery coolant. Flood is okay, but now you know why we have a coolant window in a sliding door on the lathe
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)