You could do this without the salt bath, but you would need a molten lead bath.
Lead melts around 325C, just above the Ms temperature. Holding it in the molten lead bath for 15 minutes should be adequate, after which you could air cool. With a sample of that size, you should be able to quench the sample to below 500C before it started to transform. I'd be surprised if you achieved 100% banite, but you should be able to come close; you might find you formed some ferrite. Of course, you have the problems and issues of dealing with molten lead (getting some salt would be easier, in my opinion).
I am curious, though, what are you trying to accomplish?
rp