u'amea u'amea e tusa ai ma le fa'aogaina o metotia fa'agaoioiga ua vaevaeina i: fa'amama fa'amama fa'ameamea ma le tipiina o le sila; E tusa ai ma uiga o le tino, e mafai ona vaevaeina i ni ituaiga e lima: ituaiga austenitic, austenite-ferritic type, ferritic type, martensitic type ma precipitation-hardening type.