I obtained a collection of 8 Sorby tools with my lathe. None of them have HSS on the tool steel marked anywhere. They seem pretty tough to grind (I re-profiled a scraper) but the bowl gouge will turn blue fairly easily when sharpening. The bowl gouge also cuts very nicely for the first 2-3 passes when it has a nice bur on it then it quickly dulls. The tools I believe were purchased about 10 years ago. Would tools of this vintage be made from non-HSS? If they were HSS would they have been marked as such back then?

I'm just trying to figure out if I'm expecting too much from an excellent tool, or if I possibly have merely a good tool?