It’s interesting to look at the metallurgy of Gladii found in Europe. They are mostly wrought iron with carbon content at .03%. The edges were sharpened by forging (hammering) or sharpening on a wheel. Most were fabricated by placing strips of iron together in a sandwich. The quality is variable probably due to the skill of European smiths of the time.
The Romans, for the most part, used local smiths to fabricate swords for the army. Tacitus cites a case where Vespasian commanded that “strong cities be picked out so as to get their arms factories busy.” One of the more famous sword factories was located at Rheims.