Anzaniste -- I don't remember the details (not having run across the ubas designation in many years), but I believe that David is right about it being a currently sexy process designation from many years ago.
Low carbon (i.e. < .30% carbon or lighter carbon content than 1X30 such as 1030) steel is what is normally case hardened. Unless the part is under either repeated impact loading or an abrasive slide loading you can probably just use a tool steel (silver steel on your side of the pond) pin that you heat treated directly. The main advantage of case hardening a part is that you get a very hard surface without the brittleness associated with full-hard, fully-hardened parts.