In defence of Rome: a metallographic investigation of Roman ferrous armour from Northern Britain

Metallographic examination of seven different types of Roman ferrous armour from northern Britain dating between the late first and the early third century has revealed a complexity and variety of structures. Five specimens were made of iron hardened by warm or cold working. One fragment was of medium-carbon steel and one was of iron carburised to steel on the outside surface. Four pieces were made from folding sheets of iron or steel, variously the same piece or different metals, each with a thickness of <1 mm. Hardnesses ranged between 187 and 438 Hv. There was no evidence that the specimens had been quenched hardened or quenched and tempered.